# Report on WalMart Maxx 29 Batteries



## 84bertone (Apr 10, 2008)

Thought I would post an update on the Walmart Maxx 29's that I am using. I have 8 of them in a 2340 lb (total weight) car for 96 volts. Almost all of the mileage is about 10 miles total at any one time with a couple of times out to 20-22 miles. And yes I could go further.

Based on that type of use, I have recharged them about 40 times over the course of 2-3 months. I recharge them individually directly after each use, with a 6 amp charger.

So far they are doing just fine. In fact, they seem to have gotten stronger. That could be a result of cooler weather. They all still read within one tenth of a volt of each other.

Granted, this is not a long term test just yet, so I may wind up being disappointed as some have said about the Maxx 29's. But so far so good.


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## DONEAL (Sep 10, 2008)

84bertone
what was the cost? and the weight? eight 12 v at 2340, that must be total weight ev and batteries?


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## 84bertone (Apr 10, 2008)

The batteries were $74 each for a total cost of $592. They weigh 65lbs each. Yes, that is the total weight of the car, batteries, all components, everything. 2,340 lbs. Fairly light for an EV conversion and still under the Max GVWR for the car so did not have to do any thing to the suspension.


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## TheSGC (Nov 15, 2007)

I haven't finished my EV yet, but I have the MAXX29s. I am wondering if you have the Exide or Johnson Controls version of the Maxx29. While I haven't done anything more than drive up and down the driveway, I am pleased with them so far. I have individual 6 AMP chargers for each battery and they seem to charge them nicely.

What speed were those miles at? I am hoping for a 32 mile range at 40 MPH. But I am trying to get a charge at my destination and hope to take that down to 16-17 miles per charge.


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## gmijackso (Sep 30, 2008)

Please keep us updated on your findings with these batteries. I'm considering them for my project. They're the same price as some golf cart batteries locally, but the Maxx batteries have a longer warranty. I'm very interested in how they hold up, and how the warranty goes if you should have any problems.


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## 84bertone (Apr 10, 2008)

_What speed were those miles at? I am hoping for a 32 mile range at 40 MPH. But I am trying to get a charge at my destination and hope to take that down to 16-17 miles per charge._

Most of it is around the 30-40 mph range with a couple of runs at 50-55 mph. I have twice run for better than 12 miles at 50-55 mph in 4th gear with no problem. I can readily go 25-30 miles at at 30-40 mph. I do drive easy and watch the amps closely.

You did not state what voltage or how many batteries you plan to use or how much weight your ev is. With my setup, I can easily go 16-17 miles and still have plenty left.

I was told that batteries like to be bulk charged. I personally do not believe that and these Maxx 29's respond well to individual charging as you plan to do. As I stated, they still read within one tenth of 1volt. So they are still well equalized.

Since the Maxx 29's are not true deep cycle, golf cart type batteries, I think that the best possible care for them will prevail for the long run.

Some folks have not been happy with these for EV use. All I can do is report my own experience with them and so far they are doing well.

I have the Exide version batteries but I doubt that there is little if any difference between the two versions.


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## TheSGC (Nov 15, 2007)

84bertone said:


> _What speed were those miles at? I am hoping for a 32 mile range at 40 MPH. But I am trying to get a charge at my destination and hope to take that down to 16-17 miles per charge._
> 
> Most of it is around the 30-40 mph range with a couple of runs at 50-55 mph. I have twice run for better than 12 miles at 50-55 mph in 4th gear with no problem. I can readily go 25-30 miles at at 30-40 mph. I do drive easy and watch the amps closely.
> 
> ...



I am having a 96 volt system like yours and an estimated 2500 lbs of EV. I seem to be the only person with the Johnson Controls Maxx29 version. So from your finds so far, my 32 mile range goal isn't impossible. And I do drive back roads and slowly. I also have a good 2 or 3 miles of drive that I am lucky if I get past 25 MPH due to inner city traffic.


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## TexasCotton (Sep 18, 2008)

Nice post on using super Wally world's as a battery supply. Did you pay core cost too? I have been curious and wonder if you could by in quantity from Wal Mart, AutoZone, and PeP Boys? I did have a Maxx battery on my 1997 Ford Ranger and lasted about 4 1/2 years.


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## TheSGC (Nov 15, 2007)

TexasCotton said:


> Nice post on using super Wally world's as a battery supply. Did you pay core cost too? I have been curious and wonder if you could by in quantity from Wal Mart, AutoZone, and PeP Boys? I did have a Maxx battery on my 1997 Ford Ranger and lasted about 4 1/2 years.


I had to go to three Wally Worlds to get mine because none carried enough. I bought one for testing, and then went back two more times to different stores because one had two batteries and the other had the last 5 i needed. And damn, the back of our minivan was riding low.....


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## 84bertone (Apr 10, 2008)

_Nice post on using super Wally world's as a battery supply. Did you pay core cost too? I have been curious and wonder if you could by in quantity from Wal Mart, AutoZone, and PeP Boys? I did have a Maxx battery on my 1997 Ford Ranger and lasted about 4 1/2 years._


No, I did not pay core cost because I had 8 old batteries collected through the years. Yes, I bought all 8 at the same Wal-Mart and they still had one left.

I have to add some important info on my conversion that may be of some significance. I purchased tires that allow me to keep them at 50 psi and I use Amsoil sythetic oil in the gearbox. I do not have hills to contend with. Also, I have a small 12 volt battery for all accessories so they do not draw anything off the pack.

_I am having a 96 volt system like yours and an estimated 2500 lbs of EV. I seem to be the only person with the Johnson Controls Maxx29 version. So from your finds so far, my 32 mile range goal isn't impossible. And I do drive back roads and slowly. I also have a good 2 or 3 miles of drive that I am lucky if I get past 25 MPH due to inner city traffic. _

Well, with what you describe, I think you may be able to do it. Careful driving is important. Easy starts, coasting, and such.


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## TX_Dj (Jul 25, 2008)

It's not uncommon for a new pack to "get stronger" with a few cycles. These are called (by some) as the "break-in" cycles.

I can't explain it, but it takes a few cycles before they "optimize capacity"...

The true test of value for these batteries will be in the overall cycle life.

Traditionally, the cheap "marine deep cycle batteries" tend to die after just a couple hundred cycles at most... which of course means you'll end up paying 2-5 times as much to stay with that battery as you would to buy a "real deep cycle" traction battery to start with.

But, as with everything, YMMV.


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## TheSGC (Nov 15, 2007)

TX_Dj said:


> Traditionally, the cheap "marine deep cycle batteries" tend to die after just a couple hundred cycles at most... which of course means you'll end up paying 2-5 times as much to stay with that battery as you would to buy a "real deep cycle" traction battery to start with.
> quote]
> 
> That's what the 18 month free replacement is for.  I plan on first babying them in their initial 20-30 cycles, and then give them some limited abuse and see how they take it. I went cheap because A) I could afford them and B) the warranty lets me beat the living crap out of them and not care. If Wally World asks, I have a really demanding boat.
> ...


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## TexasCotton (Sep 18, 2008)

I jacked up my "free" replacement with the wally world "Max". Truck would not start and got a lift from a stranger who took me to AutoZone for swap


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## gmijackso (Sep 30, 2008)

TexasCotton said:


> I jacked up my "free" replacement with the wally world "Max". Truck would not start and got a lift from a stranger who took me to AutoZone for swap
> Anyway wally world, autozone, pep boys, and oreally all have or "say" limited lifetime on some of the batterys they sell. So like their top line battery will usually have a 3 to 5 year warranty period with doucumentation.!!!!!


So far in my limited search, the Maxx batteries 18month free replacement has been the longest warranty I could find for a "deep cycle" battery that was at a "standard" store. Many of the 3 - 5 year warranty batteries are standard starting batteries. I have one of the Auto-zone old top of the line starting batteries and it was a 3 year free replacement 5 year pro-rated.

I am considering the Maxx batteries based on the warranty as well. I won't be using the EV much, and the extra warranty should pay for the shorter life span. The way I see it, it's like a laptop warranty. If you're not getting the "free battery replacement" with a month or so left on the warranty, you're wasting a free battery. So, run the Maxx and replace them as the fail, and do your best to replace them all just before the warranty runs out. If they'll last 6 months without needing any replacement, that means you got a 2 year pack that was always almost new.


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## TexasCotton (Sep 18, 2008)

I have best experience with Oreally,Pep Boys, and Wal Mart. Autozone just wants to get you in and back out. The battery warranty and pro rate is nice. Pro rating the battery is a "gimmick" to make the battery sale. I am curious how good the wal mart motorcycle and jet ski batterys last?


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## TexasCotton (Sep 18, 2008)

Wally worlds battery are made by Johnson Control the battery goes by brand name Everlast and Everlast Maxx which some are AGM.


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## TheSGC (Nov 15, 2007)

84bertone, any more updates on your progress with these batteries? I am just breaking mine in and keeping on eye on everything with a PakTrakr.

What are your EV specs? I can't find a Garage entry so I am curious on what you are driving.


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## Killowatt (Jan 3, 2008)

These sound like good batteries, are they deep cycle?


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## Bruce A (Jul 17, 2008)

Got the same Batteries.
http://www.diyelectriccar.com/garage/cars/72


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## armory (Dec 27, 2008)

http://www.ripoffreport.com/reports/0/253/RipOff0253439.htm

I'm not sure about the warranty.


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## 84bertone (Apr 10, 2008)

The Maxx 29's are still doing well. As good as when I installed them and it has now been almost 7 months ago. I have them installed in a 84 X/19 Bertone/Fiat. Total weight of 2340 lbs using a LogiSystems controller. It is a 96 volt system with a Jim Husted motor. I think the verdict is still out as to real long term use on these batteries. But so far, I am satisfied. I have been getting about 20 miles range at 40-45 mph and have had the car to 65 mph.

After reading about failures on the LogiSystems controllers, I contacted LogiSystems and they said to send mine back for updates. However, I have not done that yet but probably will before the warranty runs out even though mine is working fine.


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## Nalgman (Jan 23, 2009)

Hey all, just thought I'd drop my .02 worth in. After reading that the batteries are made by both exide and johnson controls I decided to ask my brother (who worked in automotive in walmart for some years) about them. He told me that our local walmart used to carry only johnson controls batteries and they were great. in more recent years our walmart has shifted to carrying exide batteries, which apparently are not so great. He told me that within six months he'd had more returns of faulty exide batteries than in the previous two years when only johnson controls batteries had been sold.

hope this helps


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## EV59RAG (Oct 6, 2008)

for the OP... any update on your batteries?


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## 84bertone (Apr 10, 2008)

EV59RAG said:


> for the OP... any update on your batteries?


Yes. I can say that they did not fare well in cold weather. Range was cut to almost half in temps of the 40's or lower. Even temps in the 50's affected them considerably. However; once warmer weather appeared, the batteries seem to perform as they did previously. Quite well.

I finally sent the controller back to LogiSystems for the upgrade so have not been able to use the car lately. The controller was working fine but they requested I send it back for rework anyway. I must say that LogiSystems is easy to work with and they back their product. I believe they really do want satisfied customers.


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## TheSGC (Nov 15, 2007)

So what is your official Range on your setup? Have you ever run them dead or is there still power left?

I haven't run mine into the ground yet and the furthest I have driven has been 10 miles in sub 40F weather. I have been using a PakTrakr, but didn't have it setup right until a few weeks ago, and the EV was already off the road for a motor upgrade. (Still waiting on it...)

I see you haven't made a garage entry yet, maybe you should because I am curious on your setup.


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## 84bertone (Apr 10, 2008)

TheSGC said:


> So what is your official Range on your setup? Have you ever run them dead or is there still power left?
> 
> I haven't run mine into the ground yet and the furthest I have driven has been 10 miles in sub 40F weather. I have been using a PakTrakr, but didn't have it setup right until a few weeks ago, and the EV was already off the road for a motor upgrade. (Still waiting on it...)
> 
> I see you haven't made a garage entry yet, maybe you should because I am curious on your setup.


 
The maximum range I have gone is 26 miles. That is mostly in the 35-40 mph range with a couple of miles at 50-55. The ambient air temperature was 80 degrees F. and the total resting voltage of the battery pack read a little better than 96 volts after the run. The chart I have equates that to about 50-55 percent SOC. Also, that was last summer when the batteries were fairly new.

A couple of weeks ago, with the ambient air right at 40 degrees F., I ran the car 16 miles and the batteries were at 86 volts which equates to something around 30 percent SOC. That is the first and last time I will take them that low. I simply made a mistake and took the car too far not realizing how much the colder temperature was depleting the batteries. So........I limped home and doubt that I could have gone another mile. However; I put a charge back on them and the batteries seem to be fine. 

I do not have the PakTrakr. I have a digital gauge across the battery pack mounted in the dash and use that as a guide for SOC. I use a multimeter and keep tabs of each battery (not while driving) to make sure one is not misbehaving.

Sorry about not getting the car on the Garage entry board. I am not that computer savvy but will work on putting it in there.


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## orange4boy (May 1, 2008)

I am using the Johnson Controls 12V marine batteries from Costco. Probably the same batteries. Got a pair for my Auranthetic at end of season for $49 each

A couple of things to watch out for are acid stratification and cell balance. 

The stratification can lead to undercharging because it causes the voltage to read high so you and your charger are fooled. You can check this yourself with an electrolyte tester. Take some cell readings and a voltage reading and note them down. Then put the caps back on and tip the battery over a few times, tipping toward the terminals, to mix up the electrolyte, then take another reading. Voltage may drop and specific gravity may rise. If so, you had some stratification. Too much will cause undercharging and sulfation.

Cell balance. Check your electrolyte readings regularly both before and after discharging to check for low cells. I had one cell in a battery that went down to 50% while the others were still at 80% so my range was cut in half and I almost killed the battery. Now I'm trying to equalize it... still not there. I may kill it trying to save it. 

None of my chargers have been fully charging my batteries so now I have been applying a soak charge manually. What a PITA. This makes buying a good charger worth it. 

Good luck with your EV.


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## TheSGC (Nov 15, 2007)

Just my update: I have over 500 miles on the MAXX29s in my Civic, and I had two go bad. Actually, they weren't getting fully charged and after many miles of driving the would get to 10.5 volts and 7.5 volts while the other were still at 11.2 under 150 AMP load, and 12.00v when letting off the pedal.

I have them replaced and now breaking them in. Used the smart charger and it gave them an equalization charge then normal charge for about 4 hours each at 2 AMPs before becoming "full".

It was not a fault of the batteries, but more fault of my K&W charger. The charging voltage was too low and would not charge them up all the way and that led to sulfation. I just never noticed until I pushed my EV to 16.5 miles, instead of the usual 14 miles. The PakTrakr started to flip out with a 12 volt battery now being 7.5 volts and I had to slow down from 40 MPH to 25 to keep the two in question about 10.5 volts under load.

The charger uses a small POT to change charging voltage and it gets moved around I guess. I have since fixed the problem, but just replaced the batteries instead of trying to work with them. 18 month free replacement came in handy.


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## 84bertone (Apr 10, 2008)

I have better than a years worth of use on the WalMart Maxx 29's. None have failed and they have been recharged about 150 times. They are still performing o.k., although they do not seem to be as robust as they were but this may have nothing to do with the batteries. I have never had to add water to them and fully charged resting voltage on them are all within a couple tenths of a volt of each other.

They are usually charged at about 60-70% SOC and have once been taken to 30%. Most driving is less than 12 miles. 

It may be a true statement to say that these batteries have been babied. The utilization of these batteries may not be representative of the average user. This is simply the way I have used them. All in all I am still satisfied with them but it still remains to be seem how well they will last into the out years. If I get 3-4 years on them, I will consider them a good value. However; I think I will replace them with the new lithium batteries once these quit.


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## TheSGC (Nov 15, 2007)

84bertone said:


> I have better than a years worth of use on the WalMart Maxx 29's. None have failed and they have been recharged about 150 times. They are still performing o.k., although they do not seem to be as robust as they were but this may have nothing to do with the batteries. I have never had to add water to them and fully charged resting voltage on them are all within a couple tenths of a volt of each other.
> 
> They are usually charged at about 60-70% SOC and have once been taken to 30%. Most driving is less than 12 miles.
> 
> It may be a true statement to say that these batteries have been babied. The utilization of these batteries may not be representative of the average user. This is simply the way I have used them. All in all I am still satisfied with them but it still remains to be seem how well they will last into the out years. If I get 3-4 years on them, I will consider them a good value. However; I think I will replace them with the new lithium batteries once these quit.


What is your AMP draw when accelerating and cruising? I can now do 18.5 miles with little effort, but I try to limit cruising AMPs to 80 or less, and accelerate with less than 250 AMPs, usually 150 if possible. My performance isn't great, and I think it's all to do with my weeny controller just eating AMPs. The batteries usually read 95-96+ after letting off the pedal after the 18 miles.


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## 84bertone (Apr 10, 2008)

TheSGC said:


> What is your AMP draw when accelerating and cruising? I can now do 18.5 miles with little effort, but I try to limit cruising AMPs to 80 or less, and accelerate with less than 250 AMPs, usually 150 if possible. My performance isn't great, and I think it's all to do with my weeny controller just eating AMPs. The batteries usually read 95-96+ after letting off the pedal after the 18 miles.


Amp draw is like yours. 80 or less. Acceleration amps is about the same. As for performance, it is not as robust as first was. However; I believe the controller setting is a bit different due to LogiSystems reworking it. I have never really tried to see how the car would accelerate if I reset the controller for a bit more agressive operation. I am content to pretty much at least stick with the flow of traffic. For our use, that is usually under 45mph.


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## TheSGC (Nov 15, 2007)

84bertone said:


> Amp draw is like yours. 80 or less. Acceleration amps is about the same. As for performance, it is not as robust as first was. However; I believe the controller setting is a bit different due to LogiSystems reworking it. I have never really tried to see how the car would accelerate if I reset the controller for a bit more agressive operation. I am content to pretty much at least stick with the flow of traffic. For our use, that is usually under 45mph.


It sounds like your actually performance is a better than mine. Pedal to the floor will get me to about 40-45, 50 if down a hill. When my new Synkromotive comes in I will also add another battery to up the voltage to 108 to keep up with the flow easier. I usually try to maintain 35 MPH, and when inclines come into play that gets messy, so if you can maintain your speeds it must be my controller.


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## 84bertone (Apr 10, 2008)

TheSGC said:


> It sounds like your actually performance is a better than mine. Pedal to the floor will get me to about 40-45, 50 if down a hill. When my new Synkromotive comes in I will also add another battery to up the voltage to 108 to keep up with the flow easier. I usually try to maintain 35 MPH, and when inclines come into play that gets messy, so if you can maintain your speeds it must be my controller.


Yes, I have no problem maintaining speed. The weight of my car is 2340 with me in the car. I have had the car better than 60mph and when I take it to church (7miles away), I cruise quite nicely at 50-55mph. I believe a more robust controller will yield you some surprising results.


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## Salty EV (Jun 8, 2009)

I wonder how the wally world maxx29 compare to the AutoZone Duralast 24MD-DL. I currently have 4 of those in my golf cart that I just started using with the new batteries. I got them since they are only like a mile from my house I believe around $70 a battery. I however will be doing the extreme end and doing full throttle 400amp starts and really be punishing these things since its more of a toy then transportation. They are maintained well though so it will be interesting to see how they last.


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## TheSGC (Nov 15, 2007)

Salty EV said:


> I wonder how the wally world maxx29 compare to the AutoZone Duralast 24MD-DL. I currently have 4 of those in my golf cart that I just started using with the new batteries. I got them since they are only like a mile from my house I believe around $70 a battery. I however will be doing the extreme end and doing full throttle 400amp starts and really be punishing these things since its more of a toy then transportation. They are maintained well though so it will be interesting to see how they last.


Well the Duralast are made by Johnson Controls, who makes my MAXX29s and also 84betone's, so they should be similar in build quality, though the MAXX29 have more capacity and are a larger battery. 

400 AMPs from floodies is pure murder on them. I am surprised they haven't popped on you. 

I keep mine under 1600 at all possible, and never past 300 amps, and when I do I let off the pedal. I can't wait until I get my Synkro, then I will be able to limit the battery current to keep the abuse down to 250 AMPs or maybe even 225 AMPs depending on how it goes.


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## Salty EV (Jun 8, 2009)

TheSGC said:


> Well the Duralast are made by Johnson Controls, who makes my MAXX29s and also 84betone's, so they should be similar in build quality, though the MAXX29 have more capacity and are a larger battery.
> 
> 400 AMPs from floodies is pure murder on them. I am surprised they haven't popped on you.
> 
> I keep mine under 1600 at all possible, and never past 300 amps, and when I do I let off the pedal. I can't wait until I get my Synkro, then I will be able to limit the battery current to keep the abuse down to 250 AMPs or maybe even 225 AMPs depending on how it goes.


Keep in mind the 400amps is only for a few seconds during launch, and after that I just cruise. They are also rated to 575, they are taking it so far, but hey if they pop, thats what warranty if for right


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## TheSGC (Nov 15, 2007)

Just a quick update: The 60F and below temperature has really taken a toll on my range. So i whipped up a quick insulated box from 1" insulation foam board and duck tape. It did wonders for my drive today. My batteries have been at 63F and 58F for the past two morning drives, but today it was 81F and drove great. I probably could make it hotter if I timed my charging just right as the batteries were 92F last night with 10 AMPs going into them.

I also watered them, which took about an hour because the tops are easily accessible. 

On another note, I have changed my controller order from a Synkro to a Zilla, so I should have that in the next month or so.


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## Guest (Sep 10, 2009)

Wow, Jump directly to the Zilla. Might be what Synkro needs to be upgraded to. If the synkro were a 1k amp controller and sold as a beginning controller before upgrading to the zilla it would be good for the Synkro. I have been looking at all the different versions of the Zilla and what a mad house of decisions to make. This or that or this with that and maybe I should buy that just incase I decide I want more later. 

Well, a good choice any way and you will be happy with the Zilla too. What version did you get? At least you will be in the 1k amp range now. Wooooo Hooooo. Glad to see Zilla back but not so glad because I spent money on the Synkro. I do like my Synkro but now the zilla is back................... I will talk with them. 

Pete 

PS. Have not been able to pull 700 amps yet from my controller. It is a nice controller and I give Synkro a full hardy thumbs up for an excellent controller.


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## TheSGC (Nov 15, 2007)

gottdi said:


> Wow, Jump directly to the Zilla. Might be what Synkro needs to be upgraded to. If the synkro were a 1k amp controller and sold as a beginning controller before upgrading to the zilla it would be good for the Synkro. I have been looking at all the different versions of the Zilla and what a mad house of decisions to make. This or that or this with that and maybe I should buy that just incase I decide I want more later.
> 
> Well, a good choice any way and you will be happy with the Zilla too. What version did you get? At least you will be in the 1k amp range now. Wooooo Hooooo. Glad to see Zilla back but not so glad because I spent money on the Synkro. I do like my Synkro but now the zilla is back................... I will talk with them.
> 
> ...


I got the Zilla 1K-LV, and it's going to be a big jump from my 400 AMP Kelly, which really only puts out 180 AMPs when I need the power. I just have to make sure I don't abuse these MAXX29s too much.

I never thought I would ever get a Zilla due to the price, it was just a dream. However, an opportunity arouse and I took it last night to be on the list of the new batch from EV Components. Putting a Zilla in a 96 volt commuter EV that I only take to 35 MPH seems overkill at the moment, but then again I like overkill.


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## Guest (Sep 10, 2009)

Actually I do not think it is overkill. I think your setup is under powered and you will soon want more. I can almost guarantee it. That is the natural progression of things you know. 

Pete 

I went from 72 volts 550 amps to 96 volts and 700 amps and still I want more. For now it will do but another upgrade is going to happen.


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## TheSGC (Nov 15, 2007)

gottdi said:


> Actually I do not think it is overkill. I think your setup is under powered and you will soon want more. I can almost guarantee it. That is the natural progression of things you know.
> 
> Pete
> 
> I went from 72 volts 550 amps to 96 volts and 700 amps and still I want more. For now it will do but another upgrade is going to happen.


I know I want MORE, but my wallet doesn't agree with me. I almost couldn't get the Zilla due to money being sucked for college, then I realized I use that money for gas and I don't use gas anymore!

BTW, it was 48F outside today and 76F in my battery box. I had the EV on a 6 AMP charge over night and that worked out great. I do a 12 AMP charge at school during the day and now a 6 AMP charge at night to prolong battery life and let the actual charging take most of the night.

I am still learning to drive the EV better, I had 40% pack left after 16.5 miles of driving, pretty good over the 30% I had yesterday. And it was colder today. I noticed I burn up a lot of AMPs trying to make it up hills due to the Kelly not giving enough poop to go. I am expecting a range increase of about 2-3 miles with the Zilla properly calibrated to limit battery current to 225 or 250 AMPs peak.


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## TheSGC (Nov 15, 2007)

It's Official: I murdered my battery pack. Really, the Kelly murdered it with only low voltage slow down but no battery current limiting, and my balancer's came too late to the game.

I was on my way home from school today, driving nicely doing 30 MPH and the next thing I know my voltage goes from 94 volts under load down to 78 volts and the Kelly just shuts down and I coast into the nearest parking lot of a middle school. After sitting there for 5 minutes thinking about being 4 miles from home and calling AAA, I find a plug on the side of the school, and the principal allowed me to charge without a problem. After a 20 minute charge, I head home with a Pack voltage of 98.7 volts, 3 miles later, again the cruising voltage of 94 (80 AMPs) drops to 78 and the EV shuts down two streets from my house. I ended up overriding the low voltage shutdown just to make it home, and I just pulled up 6 batteries that need replacing, since I already replaced 2 earlier this month. 

BTW, I have nearly 1,000 miles on this pack and it's been greatly abused. When seems to happen is that I will be driving, only taking 110-150 accelerating, then my transmission will shift and the Kelly starts sucking up 300+ amps, pure murder for the floodies. When fully charged, the batteries dont seem to mind it, but I need that power saved for the overrall trip.

Oh, and a full charge after the 17 miles trip only takes 6.5 hours at 10 AMPs, but its been a little longer now that my balancers actually seem to be doing somethings, just it's not enough about nearly 1,000 miles of abuse.

And yes, I am getting these replaced under warranty, hopefully most of them tonight.


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## TheSGC (Nov 15, 2007)

I replaced all but one of my batteries (Walmart ran out). It turns out that I also need to do an equalization charge on these every 10-15 cycles for proper life span, so I am attempting that on the last battery to see what it does. This particular battery is not only my oldest, but was also one of the strongest of the pack, possible due to some equalization that I did a this past summer when I took it on a camping trip to charge the phones, iPods, etc. 

Still plan on getting it replaced so the pack will be even, but this equalization charge will be a test to see how the process goes. 

I am hoping to start to break in this new pack this weekend, but for now on my Friday/Saturday charges will be equalization charges.


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## jondoh (Sep 8, 2008)

regarding the equalization, i'd also call this cell balancing. You can have this done automatically every time you charge by using voltblochers. go to:

http://www.voltblocher.com

choose the one for lead acid.


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## TheSGC (Nov 15, 2007)

jondoh said:


> regarding the equalization, i'd also call this cell balancing. You can have this done automatically every time you charge by using voltblochers. go to:
> 
> http://www.voltblocher.com
> 
> choose the one for lead acid.


Equalization is slightly different, voltages around 15-15.5 volts per battery, or 2.5v/cell.

I have actually built my own BMS shunts, a little more complicated than a Voltblocher since mine is controller by a PIC processor and programmable, and also serves as a State of Charge meter for each battery. They have only been on the EV for a few days, but the improvement was noticeable immediately during charging. I am still working out the best charging scheme for them, but so far so good.


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## MN Driver (Sep 29, 2009)

Did they ask any questions regarding why you were bringing in multiple batteries for warranty replacement? I don't know what the warranty limitations are but I can't help but think that at some locations they might give you a tough time about replacing multiple batteries at once. Does the free replacement warranty start over with the replacement where you get a new battery if one fails in another 14 months? or do they engrave/pull stickers for the date of the ones being replaced?

I can't help but imagine me bringing back these batteries one at a time to different locations and different days to avoid questions about it. Is the use of the batteries in an EV even against the warranty?

EDIT: You mentioned you would be acclerating at 110-115 amps and then your amp draw would go to 300+ amps when it shifts, can you use the shift lever in your car to select a lower gear so it doesn't upshift on its own so you can shift it later when it will provide an RPM that can provide better efficiency? Most automatics allow you to do this, is yours different?


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## Dave Koller (Nov 15, 2008)

TheSGC said:


> I have actually built my own BMS shunts, a little more complicated than a Voltblocher since mine is controller by a PIC processor and programmable, and also serves as a State of Charge meter for each battery.


Can you share the circuit and software or are you going to keep it as proprietary ? 

I am a fan of single - per battery - charge (if the chargers work) but a single pack charger works well with shunts - SO the interest in all means of automatically shunting around individual batteries is foremost ... 

Thanks!!

Dave


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## TheSGC (Nov 15, 2007)

MN Driver said:


> Did they ask any questions regarding why you were bringing in multiple batteries for warranty replacement? I don't know what the warranty limitations are but I can't help but think that at some locations they might give you a tough time about replacing multiple batteries at once. Does the free replacement warranty start over with the replacement where you get a new battery if one fails in another 14 months? or do they engrave/pull stickers for the date of the ones being replaced?
> 
> I can't help but imagine me bringing back these batteries one at a time to different locations and different days to avoid questions about it. Is the use of the batteries in an EV even against the warranty?
> 
> EDIT: You mentioned you would be acclerating at 110-115 amps and then your amp draw would go to 300+ amps when it shifts, can you use the shift lever in your car to select a lower gear so it doesn't upshift on its own so you can shift it later when it will provide an RPM that can provide better efficiency? Most automatics allow you to do this, is yours different?



I replaced 5 batteries at one store and they didn't ask any real hard questions. They just wanted to know if I was returning them for a refund or for replacement. No, the warranty only exists from the first time you bought them. Or else you would have perpetual warranty. Each battery actually has a manufacturing date on them, which does help with warranty issues. 

I really have no idea if using these in an EV is against warranty, but I doubt it. I just have one more battery to replace, but I need to go to another Walmart since I emptied the local one. 

I can adjust my shift points and force it into 2nd gear, but with my Kelly the top speed in 2nd is about 30 MPH (it should be 50 MPH, but the controller just wont do it unless I am in 3rd, but them top speed is maybe 45 MPH in 3rd. New Zilla should fix that .) 

I really should make a manual on the proper care for these batteries. They need to be charged at 14.8 volts each, and 15.6 volts for equalization. I was usually charging at 14.2-14.4 volts, so not even close to what is really needed. and they do like getting charged at 10-12 AMPs much better than 2-6 AMPs.


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## MN Driver (Sep 29, 2009)

I disagree with the 15.6 volt figure, if you go with that high of voltage you will likely need to add water very frequently to your batteries as they will be gassing quite a bit when charged that high and possibly cause a little bit of grid corrosion each time. A higher voltage like that might work out if the temperatures are very cold but on a hot day you will likely find your new replacements dead quickly.

To equalize them you want to make sure they charge all the way full to 14.8 volts and when the amperage drops to near nothing (usually less than 100ma) you would float charge them around between 13.8volts and 14.1 volts until the total charging time has been 16 hours, or at least 6 hours from when the amperage dropped low if the batteries were very low or your charging was at a low amperage. Running a higher voltage such as 14.8 will prevent the sulphation that probably did your old batteries in. Don't forget to frequently check water levels and make sure the plates never get dry.

Take a good look at this page:
http://www.batteryuniversity.com/partone-13.htm
It discusses the advantages and disadvantages to lower voltage (2.3-2.35 volt per cell) and high voltage charging (2.4-2.45 volts). Since you are cycling these batteries I would recommend 14.8 volt charging and making sure that the batteries receive a complete charge when you get the chance, so if you are charging them at school like you said you were, once you get home you want to make sure they get as charged as possible to best prevent against low SOC sulphation which will essentially insulate your grid plates from the electrolyte.


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## TheSGC (Nov 15, 2007)

Dave Koller said:


> Can you share the circuit and software or are you going to keep it as proprietary ?
> 
> I am a fan of single - per battery - charge (if the chargers work) but a single pack charger works well with shunts - SO the interest in all means of automatically shunting around individual batteries is foremost ...
> 
> ...


I haven't really decided how I want to approach that yet. In my mind I can see a relatively decent product that could come out of it if I can get my act together with proper PCBs and Serial connection between each BMS module so they can talk to each other. But that could change.


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## TheSGC (Nov 15, 2007)

MN Driver said:


> I disagree with the 15.6 volt figure, if you go with that high of voltage you will likely need to add water very frequently to your batteries as they will be gassing quite a bit when charged that high and possibly cause a little bit of grid corrosion each time. A higher voltage like that might work out if the temperatures are very cold but on a hot day you will likely find your new replacements dead quickly.
> 
> To equalize them you want to make sure they charge all the way full to 14.8 volts and when the amperage drops to near nothing (usually less than 100ma) you would float charge them around between 13.8volts and 14.1 volts until the total charging time has been 16 hours, or at least 6 hours from when the amperage dropped low if the batteries were very low or your charging was at a low amperage. Running a higher voltage such as 14.8 will prevent the sulphation that probably did your old batteries in. Don't forget to frequently check water levels and make sure the plates never get dry.
> 
> ...



That page is specifically for VRLA batteries, not floodies. I do fully charge them at home and before I leave school everyday, so that has never been a problem. 

However, they were only getting charged to 14.2 to 14.5, sometimes less by accident. I do check water levels frequently, about every too weeks or when my PakTrakr wants me too. All flooded batteries that I can find (US, Trojan, Excide, Delphi, etc) all say that 15.5-15.6 volts is needed for proper equalization, which should be done every 15-20 cycles.


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## TheSGC (Nov 15, 2007)

I have installed my Zilla and have about 40 miles on the new setup. I have started the process of breaking in my batteries and want at least 100 miles on them before I try anything crazy like long trips or highway speeds.

I will say I am estimating my top speed to be about 55 MPH with my Zilla. I can get up to 45 MPH without any problem, using less than 200 AMPs for acceleration, driving like a crazy man. But for now I have my battery AMPs set to 175 MAX while breaking in the battery pack and that will change to 250 AMPs when the pack settles in as I need that power for climbing a few hills.


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## MN Driver (Sep 29, 2009)

Good to hear, thanks for keeping us updated.


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## Dave Koller (Nov 15, 2008)

David 
I have been lurking on your blog and you say it is too cold to work outside lol - Same here, and now we are getting pelted with a new snow storm! But for your viewing pleasure here is MY garage-in-a-box...


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## TheSGC (Nov 15, 2007)

Dave Koller said:


> David
> I have been lurking on your blog and you say it is too cold to work outside lol - Same here, and now we are getting pelted with a new snow storm! But for your viewing pleasure here is MY garage-in-a-box...


I wish I had a Garage-in-a-box! Your's looks like it's small enough to heat, even if it's just to get the edge off. And it's off the ground, how nice!

I have a new suspension on the way and my neighbor said I could use his garage to install it. He also has all sort of sweet tools, like spring compressors so that will work out.


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## TheSGC (Nov 15, 2007)

So a quick battery update-
It has been freaking cold out (10-30F) and I found that my charger was not fully charging my batteries due to the cold. I had to increase the voltage from 117 to 119.7 volts for my 96 volt pack to compensate for the cold weather. The charger has automatic compensation, but it heats itself up pretty fast and lowers the voltage a little. (It's not the charger's fault, but how I installed it.)

These guys do not like the cold, and I had to remove the top of my insulation to remove my batter balancers I built. I am rebuilding the programs on them so decided to completely remove them as my pack is nicely balanced. Tomorrow I will be sealing my pack back up and doing some more runs and finally getting my suspension system.


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## Dave Koller (Nov 15, 2008)

I am still lurking  AND following your blog once in a while - Dislike this weather also! - Even if I get the Saturn going I am not sure about winter driving - not the cold - not the snow - the [email protected]#$% SALT they overdue on the roads! 

I think the Wally world batteries are suffering no less than the Lifepo4's in the cold... The southern boys had a few surprises in the recent cold snap in the south 

Keep up the posts!!


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## TheSGC (Nov 15, 2007)

Dave Koller said:


> I am still lurking  AND following your blog once in a while - Dislike this weather also! - Even if I get the Saturn going I am not sure about winter driving - not the cold - not the snow - the [email protected]#$% SALT they overdue on the roads!
> 
> I think the Wally world batteries are suffering no less than the Lifepo4's in the cold... The southern boys had a few surprises in the recent cold snap in the south
> 
> Keep up the posts!!


They definitely work better warm/hot. I usually do two runs a day and the second run is always better, mainly because they are a good 30 degrees F higher than the first run. I have no real problem with the salt, just this darn cold. I am thinking about battery blankets with my insulation. I found some KATs blankets at Amazon.com that I might try. I don't need one for each battery, but maybe 2 or 3 for the whole pack.


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## Stunt Driver (May 14, 2009)

Joined the club.

4 of MAXX29 from Portland Wallmart. Runnign for 3 months so far, will keep track. Cold weather (25F) decreased range almost in half.


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## DONEAL (Sep 10, 2008)

How do you calculate the dod?
I have 12 maxx 29 and at full state of charge is 158.7 after 1 hour of being disconnected from the charger.
Drove 10 miles where 148.3 and after they rested for 2 hours they were back up to 151.4 
Note the 10 miles was at about an avg. of 55 mph


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## TheSGC (Nov 15, 2007)

DONEAL said:


> How do you calculate the dod?
> I have 12 maxx 29 and at full state of charge is 158.7 after 1 hour of being disconnected from the charger.
> Drove 10 miles where 148.3 and after they rested for 2 hours they were back up to 151.4
> Note the 10 miles was at about an avg. of 55 mph


I have been using a PakTrakr as the primary guide for my DoD, but I also use a Depth of Charge chart I found online: http://www.windsun.com/Batteries/Battery_FAQ.htm#Battery Voltages

Last night I finally figured out how to do an Equalizing charge on my MAXX29s. I am supposed to be equalizing them every 25 cycles, according to my sources, and after 50 cycles it's blatantly obvious it's needed because I routinely drive my batteries down to 65% DoD. 

The equalizing charge required is 15.6 volts +- temperature compensation, so yesterday I made a small unit that took the input from an IBM notebook charger and set it to 15.8 volts cause it's freaking cold here. I have a spare MAXX29 that I have been using for testing after I pulled it from my EV back in September because it was "sulfated" according to my smart charger, and I have used it MANY times since them, but the charger will end with a FLOAT/Sulfated instead of FULL because of that. Last night I fully charged that battery, then added my Equalizer for 1 hour, drained it again this morning and fully charged it again and the charger said FULL!

I am now Equalizing the batteries in my EV because they have about 20 cycles on them, and were used infrequently since October due to having to source replacement parts for my Civic EV.


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## TheSGC (Nov 15, 2007)

I have gathered enough data to say that temperature has a profound effect on the batteries, almost linear. At 82F I have full 100% capacity and can reach 20 miles to 80% Depth of Charge, at 32F I have 50% range capacity and can only go 10 miles to 80% Depth of Charge. So for every 1F below 82F, I lose 1% of capacity/range and for every 1F above 82F I gain 1% of capacity/range. 

My one way commute is 16.8 mile, so if I want 17 miles to be safe, that means my batteries need to be at least 67F to make it to my destination before I charge. Back in October I had a few days that the morning temperature was about 60F for my batteries, and my last 1.2 miles were pretty bad, down to a snails pace to keep the batteries happy.

I am looking into battery heating pads to get my pack up above 67F all year round, ideally 70F.


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## Stunt Driver (May 14, 2009)

Have tried to replace failing MAXX29 in Wallmart - and got refusal!!

One of my batteries lost 50% of capacity, but at wallmart they checked CCA and since CCA was above nominal - refused to replace it.

Moreover, they have checked CCA at room temperature.


So I am reluctant to buy remaining batteries at wallmart now. Costco may be a better option.


Any recomendations? Should I short the battery for a few days to make it fail CCA test?


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## TheSGC (Nov 15, 2007)

Stunt Driver said:


> Have tried to replace failing MAXX29 in Wallmart - and got refusal!!
> 
> One of my batteries lost 50% of capacity, but at wallmart they checked CCA and since CCA was above nominal - refused to replace it.
> 
> ...


How has it lost 50% of it's capacity? What were you using it in, etc. It probably just needs an equalization charge for a few hours, it did wonders to my batteries that I thought were failing. My PakTrakr detected two "failing" batteries, that are also the batteries the PakTrakr remotes are connected to, and they were severely undercharged compared to my others. The PakTrakr has been sucking them down, so this afternoon those too are getting some special care to bring them back up. I have been working on a scheme to bring the MAXX29 back up to spec, and it worked great on my test battery, I just need to try it to my EV this afternoon. I am even writing a paper thing on what I have been doing and what I have found.


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## Dave Koller (Nov 15, 2008)

TheSGC said:


> I have been working on a scheme to bring the MAXX29 back up to spec, and it worked great on my test battery, I just need to try it to my EV this afternoon. I am even writing a paper thing on what I have been doing and what I have found.


David:
I am interested in that! Keep me posted .....


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## orange4boy (May 1, 2008)

Costco refunded me for one of my 12V deep cycle batteries that had a bad cell within the first year. I bought them on seasonal clearance for 1/2 price but they refunded me the full price! I told them it had a bad cell and they didn't even check it.

They are the ones made by Johnson Controls.


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## Stunt Driver (May 14, 2009)

mine is actually going bad. Initial reason was poor contact with charger, but it's been undercharged for too long.
Each of my batteries is on it's own charger, so they get full cahrge every time, perfect balancing.

This one lasts for 4 miles before under load voltage drops below 10 volts. Other batteries last up to 8 miles (if I charge the bad one at 4 miles, and do not charge other batts). I can monitor individual voltages.


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## TheSGC (Nov 15, 2007)

Stunt Driver said:


> mine is actually going bad. Initial reason was poor contact with charger, but it's been undercharged for too long.
> Each of my batteries is on it's own charger, so they get full cahrge every time, perfect balancing.
> 
> This one lasts for 4 miles before under load voltage drops below 10 volts. Other batteries last up to 8 miles (if I charge the bad one at 4 miles, and do not charge other batts). I can monitor individual voltages.


Your charger most likely doesn't equalize, and the under charging creates sulfation, which equalization helps eliminate, according to Trojan Battery.

Mine did the same thing, would drop to 9.6 volts under load after 3.5 miles. An hours on the equalizer, and a charge cycle later, and it was happy with the others at 11.2 volts under load at that same 3.5 miles. Of course, I let the EV sit again for two weeks and my PakTrakr drained it much lower than the others, so it's doesn't fully charge with the rest of my pack, so I am bringing it up to spec right now. I actually have to do this two both batteries that house PakTrakr remotes power, ugh.

EDIT: I should also mention I drive a 4.8 mile test route, and my normal EV commute is 16.8 miles one way, with full charging at destination.


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## TheSGC (Nov 15, 2007)

Dave Koller said:


> David:
> I am interested in that! Keep me posted .....


I am getting more data, but I have like 3 pages full of notes that I am trying to organize into a readable, understandable paper, hopefully with graphs and data tables.


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## Stunt Driver (May 14, 2009)

my chargers take voltage up to 16v, and then drop to 15.5 and sit there for hour or so. And that is every charge.

For a test I have put that battery on 16.2 v overnight - battery got very warm by morning, but didn't get better.

So I still believe it lost capacity, probalby due to sulfation, but it looks rather irreversible now. 


Problem is in different field - Wallmart is VERY RELUCTANT to swap batteries at least in Portland.


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## TheSGC (Nov 15, 2007)

Stunt Driver said:


> my chargers take voltage up to 16v, and then drop to 15.5 and sit there for hour or so. And that is every charge.
> 
> For a test I have put that battery on 16.2 v overnight - battery got very warm by morning, but didn't get better.
> 
> ...


Charging to 15.5 volts every charge has been known to kill batteries. 15.5 volts is only supposed to occur every now and then, with 14.8 volts being the nominal charge.

How many miles/charge cycles did you get out of it?

I guess your should put on some load until the battery is so dead it barely registers. Of course, they then could just charge it up again, like they are threatening to do up here in New England this coming year.


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## Stunt Driver (May 14, 2009)

I was putting chargers to "Gel" mode sometimes, where they don't take voltage above 14.4v , but batteries definitely had alot of equalizations.

Used it since september, probably 100 cycle at most. Since i wasn't monitoring individual voltages initially - not sure for how long that one battery was undercharged.

BUT, since my chargers show voltage when plugged in - it was never below 11.9v idle (after minimal resting voltage). While at load it has gone to around 9v. Seems like a deep cycle battery should handle this ok?


So maybe it is not be, but the battery actually did fail prematurely?


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## TheSGC (Nov 15, 2007)

Stunt Driver said:


> I was putting chargers to "Gel" mode sometimes, where they don't take voltage above 14.4v , but batteries definitely had alot of equalizations.
> 
> Used it since september, probably 100 cycle at most. Since i wasn't monitoring individual voltages initially - not sure for how long that one battery was undercharged.
> 
> ...


I guess the real question is what kind of load was it under when it hits 9v? I have been adjusting my Zilla for my commute, and I have been told that I should have 9.6 volts as my Low Voltage Cutout for acceleration up hills, etc, as long as the battery comes above 10.5 volts while under "normal" resting. During the summer weather, I usually don't get voltages even close to 10.5v under acceleration or load until my last mile, and that's only when I am climbing hills. 

I found out today that my two batteries batteries that house the PakTrakr remotes are only getting charged to 80% when the rest of my pack is full. I haven't driven the EV much, so there is no damage, but it does line up with those batteries showing 20% less voltage under load compared to the others. I didn't bother to think of this, so I just threw on my Equalizer and left it on for an hour, and the next runs were better, but only like 5% because the Equalizer is only 4 AMPs. I have also had other loads that added onto the PakTrakr, such as my experimental BMS, that didn't help with drain.


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## Stunt Driver (May 14, 2009)

After 4 miles bad battery starts to sag below 9v under 70-100Amps. And it's really empty by then, because if I continue driving - it will go to 4-5volts in next mile, while other batts are still holding close to 11v at the same loads.

I was also watching other batts to be above or very close to 12v when I let go of the pedal. So they are in much better shape now,compared to bad one. 
What do you mean by 10.5v under normal resting? Meaning no load or how many apms?


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## TheSGC (Nov 15, 2007)

Stunt Driver said:


> After 4 miles bad battery starts to sag below 9v under 70-100Amps. And it's really empty by then, because if I continue driving - it will go to 4-5volts in next mile, while other batts are still holding close to 11v at the same loads.
> 
> I was also watching other batts to be above or very close to 12v when I let go of the pedal. So they are in much better shape now,compared to bad one.
> What do you mean by 10.5v under normal resting? Meaning no load or how many apms?


I consider normal resting like 15 minutes after the load is off the batteries. (15 minutes after the EV is off) The MAXX29 are supposed to be designed to go down to 7.2 volts under HEAVY load (875+ AMPS when fully charged) so it may be OK if voltages get that low for a few seconds towards the end of the commute, but keeping the batteries above 10.5 volts under a 75 AMP load is probably the best thing to do.


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## Stunt Driver (May 14, 2009)

> as long as the battery comes above 10.5 volts while under "normal" resting.


Come again, so do you keep your batteries above 10.5v under 75Amps or at idle?


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## orange4boy (May 1, 2008)

Have you checked the electrolyte in the weak battery cells? A bad cell can cause those symptoms. If the batteries are fairly new then it's probably a defect.

If a really long trickle charge after equalizing for a few hours does not bring it back then you can bring in your electrolyte tester to the Wartmole and show them that.

The one I returned had exactly the same symptoms as yours and had one cell that was dead and wouldn't take a charge. The battery showed normal voltage after charging but crashed quickly.


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## TheSGC (Nov 15, 2007)

Stunt Driver said:


> Come again, so do you keep your batteries above 10.5v under 75Amps or at idle?


It really depends how far I have drained my pack. Above 50% capacity, I will not let my batteries go below 10.5 under acceleration loads, which is usually more than 150 AMPs. Below 50%, I will let the batteries get between 10-10.5 volts at around 75+ AMPs just to keep the EV up with traffic, and if I am desperate, I will let them go as low as 9.6 volts, but I only had that happen once as a last ditch effort to not get over run by a transit bus merging up a hill.

At idle, the battery must come up above 10.5 volts (after 15 minutes in my books) or else the battery is in danger of cell reversal.


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## TheSGC (Nov 15, 2007)

I have installed my Farnam battery heater pads, and WHAT A DIFFERENCE!

With my batteries at 75F, I took a few trips yesterday and I was able to pull 265 AMPS without my pack voltage falling below 86 volts up a hill! The voltage sag is minimal, like it usually is on a nice summer day. I am really surprised on how temperature affects performance on these batteries, but that seems to be the common theme with lead acid and cold weather.

My EV is one step closer to being a full time, all year driver! I am still working on paper on these batteries, and so far my tricks/process for maintenance seems to be showing itself nicely.


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## Dave Koller (Nov 15, 2008)

TheSGC said:


> I have installed my Farnam battery heater pads, and WHAT A DIFFERENCE!
> 
> With my batteries at 75F, I took a few trips yesterday and I was able to pull 265 AMPS without my pack voltage falling below 86 volts up a hill! The voltage sag is minimal, like it usually is on a nice summer day. I am really surprised on how temperature affects performance on these batteries, but that seems to be the common theme with lead acid and cold weather.
> 
> My EV is one step closer to being a full time, all year driver! I am still working on paper on these batteries, and so far my tricks/process for maintenance seems to be showing itself nicely.


Now that is good to hear!! 

Now what kind of distance can you get from them?


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## TheSGC (Nov 15, 2007)

Dave Koller said:


> Now that is good to hear!!
> 
> Now what kind of distance can you get from them?


I am guessing 20 or so miles with all these hills, with that coming from my PakTrakr State of Charge. It takes a good 500 miles to break these suckers in, and I only have about 150 miles on them, so full performance won't happen for a while, but I will start to lengthen my drives, with the next one being 10 or so miles.


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## Dave Koller (Nov 15, 2008)

I went to your blog to see more - all your heating is done during charge with AC? With all that insulation it should hold for most trips in freezing weather!

Keep up the great pictures there


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## DONEAL (Sep 10, 2008)

I can make a small report on my Maxx-29 batteries. They seem to be holding up real good so far. I have 236 ev miles logged so it is still early. 
I’ve added an update on my build thread http://www.diyelectriccar.com/forums/showthread.php/1992-s-10-chevrolet-build-38834p6.html


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## TheSGC (Nov 15, 2007)

Dave Koller said:


> I went to your blog to see more - all your heating is done during charge with AC? With all that insulation it should hold for most trips in freezing weather!
> 
> Keep up the great pictures there


Yep, all my battery heating is done with AC power. When the EV is driving, the batteries stay warm, and once I get to my destination they get thrown back on the charger and stay nice and warm.

I had the heater's off last night and with my batteries at 63F they were not nearly as happy and they are at 75F.


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## TheSGC (Nov 15, 2007)

Time for an update:

I have 350 miles on this pack (1350 miles total on EV) and I have been experiencing two "low" batteries according to my PakTrakr. I can drive 12-13 mile perfectly fine, then batteries 1 and 2 go real low when under load, then pop up once I let off the pedal. I have been going crazy over it for the past two weeks, and have even started looking into a higher capacity pack. Well, this evening something hit me while I was reading another EV'ers blog: I am basing all my information on my Paktrakr, and that may not be working properly. 

I am using two PakTrakr remotes, so tomorrow I am going to switch them and see if that changes anything when I do a 12-13 mile drive. 

A few months ago I removed all my batteries when I installed my heater pads, and I check the SG and they were all basically the same (+/-0.005 of each other) so my logic says they are all in the same condition.


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## JRoque (Mar 9, 2010)

> I can drive 12-13 mile perfectly fine, then batteries 1 and 2 go real low when under load, then pop up once I let off the pedal.


Hi. Could the sag be due to bad connection between bat #2 and #3? If bat is suspect, can they be swapped with others on the string to check?

JR


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## TheSGC (Nov 15, 2007)

JRoque said:


> Hi. Could the sag be due to bad connection between bat #2 and #3? If bat is suspect, can they be swapped with others on the string to check?
> 
> JR


I could try that, or try swapping cables, which would be easier. One thing I do know is that batteries 1 and 2 use the same PakTrakr wires, so if something is wrong, they could report bad readings? I'll am also going to do a full record of my next run using my Zilla and see if the pack voltage from the Paktrakr and the Zilla match under load. If the Zilla reads higher, then there is something funky with my PakTrakr.


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## Dave Koller (Nov 15, 2008)

TheSGC said:


> I could try that, or try swapping cables, which would be easier. One thing I do know is that batteries 1 and 2 use the same PakTrakr wires, so if something is wrong, they could report bad readings? I'll am also going to do a full record of my next run using my Zilla and see if the pack voltage from the Paktrakr and the Zilla match under load. If the Zilla reads higher, then there is something funky with my PakTrakr.


Are 1 & 2 closest to the motor? Hence, the most RF introduced. The leads are not shielded (as of other references by owners) on the Pak Trakr. Twisting Pairs on everything seems to be a "quick fix". Got a scope?


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## TheSGC (Nov 15, 2007)

Dave Koller said:


> Are 1 & 2 closest to the motor? Hence, the most RF introduced. The leads are not shielded (as of other references by owners) on the Pak Trakr. Twisting Pairs on everything seems to be a "quick fix". Got a scope?


All the batteries are in the trunk, but the two batteries in question do are next to both high voltage cables and have the paktakr remote ontop of the battey. And yes, I do have a scope that I might pull out and play with.


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## TheSGC (Nov 15, 2007)

I swapped the remotes and did a test today, and I did see a little difference on the PakTrakr. But the real interesting thing I found was that the cable that goes from battery 1 to 2 was HOT! The PakTrakr remote was resting ontop of it, and when I decided to check the PakTrakr during charging (after 3 hours) it was 104F! It also has 9x the voltage drop than the others at 2 AMPs charging current! I am going to let the charging finish and then remove the cable and replace it with one of my spares. I have at least 4 spares here that I will pull out and check the resistance of them.


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## Dave Koller (Nov 15, 2008)

Ah hah !!! Lol


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## TheSGC (Nov 15, 2007)

Dave Koller said:


> Ah hah !!! Lol


Yeah, when you get EV Tunnel Vision it's real easy to over look the simple things, like power cables. I am going to have to make a checklist of what to check when things go wrong.

I didn't get to go out and do my full test yet, but I did get around to do 3.7 miles and I did see an improvement in the two batteries. Tomorrow or Saturday I will get to do a full test and see if there is any real improvement. If I can get a solid 14 miles, my dad will take the EV to work to save some money from filling the huge tank of his minivan, over $45 a week.


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## Dave Koller (Nov 15, 2008)

OK David! 

Question for you. 

Did you hex crimp the cables or hammer-slam and did you use no-ox ? Mine are double hex crimped, no No-ox, and used heat shrink with adhesive type..

Since you have become a "don't do it this way" and blazed a trail - Lurkers would like to know!


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## TheSGC (Nov 15, 2007)

Dave Koller said:


> OK David!
> 
> Question for you.
> 
> ...


Well, I never made these cables. I got them from another EV'er who's S-10 was taken off the road due to a dead controller and then I got all the EV components, including cables, motor, DC/DC, contactors. 

I do believe these cables were crimped AND soldered, so they are good stuff, but they did have over 10 years of corrosion on them that I didn't do a good enough job removing on a few of them. I spent a bit of time with heavy grit sand paper cleaning a few cables, and they came out nice and shiny.

I think a big part of my problems is that I like to try so many things, usually whatever is the quickest of work up from there. There is also a part of me that always wants to do something because if my EV was completed, I wouldn't know what to do with myself.


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## Dave Koller (Nov 15, 2008)

Got ya...
I think the INTERNAL condition may have some corrosion on the INSIDE...

Glad you found this - makes one think!

I see you are on also.. lol just got back from a track meet at HS...


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## TheSGC (Nov 15, 2007)

Dave Koller said:


> Got ya...
> I think the INTERNAL condition may have some corrosion on the INSIDE...
> 
> Glad you found this - makes one think!
> ...


Yep, the inside of the terminal was not too pretty. I will try and post some pictures this weekend of the cables as I got them, what they looked like when I cleaned them up, and the connection ends of the "Hot" one.


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## Dave Koller (Nov 15, 2008)

Ok - I meant it my be on the inside of the wire to lug... After ten years! But if it is better than great cause it would be a tough one to get into the wire !!


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## TheSGC (Nov 15, 2007)

The battery was a little better today, but not by a whole lot. I decided to do an equalizing charge for 3.5 hours after normal charging finished and I will try driving again tomorrow. 

I am finding that one should not pull more than 1.75C from flooded lead acid, which translates to no more than 218 AMPs from the MAXX29s, and I punch 265 AMPs from them every few miles for hills and intense acceleration. My old Kelly could barely pull 180-210 AMPs from the batteries, so they were pretty happy. Hill's really sucked, but they stood up. Now with the Zilla I have the power to zip around, but the batteries are crying when I accelerate.


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## JRoque (Mar 9, 2010)

Hey SGC, can you live with a little less total voltage? If you're running right now at 144V, can you live with, say, 96V in terms of speed? If you can, you might want to consider taking a few of your bats from the series string and paralleling them. For example, if you're running 12V bats for a total of 144V - which gives good speed, taking 4 of those batteries and paralleling them on the last battery before going to the controller will give you a bit more current while sacrificing speed somewhat.

Beyond this, has anyone consider splitting their pack in two and dynamically configuring between series and parallel during acceleration? There will be a few contactors in the system but it would work like this: you start out at slow speed with half your voltage, twice the current for lots of torque and hill climbing ability. Once you've reach the top speed of your halved pack, you then configure it to series and add more speed. There will be a "bump" in there while the contactors switch things around but it wouldn't be half as bad as shifting to your highest gear.

Regards,
JR


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## TheSGC (Nov 15, 2007)

JRoque said:


> Hey SGC, can you live with a little less total voltage? If you're running right now at 144V, can you live with, say, 96V in terms of speed? If you can, you might want to consider taking a few of your bats from the series string and paralleling them. For example, if you're running 12V bats for a total of 144V - which gives good speed, taking 4 of those batteries and paralleling them on the last battery before going to the controller will give you a bit more current while sacrificing speed somewhat.
> 
> Beyond this, has anyone consider splitting their pack in two and dynamically configuring between series and parallel during acceleration? There will be a few contactors in the system but it would work like this: you start out at slow speed with half your voltage, twice the current for lots of torque and hill climbing ability. Once you've reach the top speed of your halved pack, you then configure it to series and add more speed. There will be a "bump" in there while the contactors switch things around but it wouldn't be half as bad as shifting to your highest gear.
> 
> ...


I am currently running a single string at 96 volts. I thought about doubling up, but it doesn't seem feasible space wise. If I had 144 volts I would be all set, my 265 AMP @96v draw up hills would be a measly 177 AMPs @144v, perfectly within the MAXX29 capabilities. However, it cost me a lot less to completely upgrade to an 8VGC and stay at 96 volts than to upgrade to 144 volts. If I wanted to increase my voltage, I would need a new circuit breaker, new DC/DC and a new charger. 

My pack now has over 1400 miles on it, and I am noticing somewhat better charging voltages on each battery. When I did my equalization charge today, they were all around 15.6 volts and sucking up 3-2 AMPs for 3.5 hours. I hope to see some improvement tomorrow, but I think I need to leave the EV on the charger for more equalizing charges over the next week or so after each drive to help.


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## TheSGC (Nov 15, 2007)

I have about 150 cycles on my pack and nearing 1500 miles. I have found a few interesting things, one being that the MAXX29 should have less than 200 AMPs max current drawn from them for best range, with normal cruising under 85 AMPs. 

I have been experiencing major voltage sag after 12.4 miles, so I decided to do a test. I have had my Zilla set to 265 battery AMPs max and 500 motor AMPs max, so I decided to adjust it to what my old Kelly used to be. (And also the last time I could drive 16+ miles repeatedly) So I set battery AMPs to ~180 and motor AMPs to 200 and drove. I could go 16 miles and didn't experience any battery issues, but my performance was terrible on acceleration and hills, just like it was before I got my Zilla. I also was easy on the pedal and kept the cruising well under 85 AMPs.

Due to this I am upgrading my pack to 8 volters but I am still going to keep my MAXX29 pack around because it is still in great condition and it would be a waste to use it as core charge. As of this afternoon I have 1461 miles on this pack and I want to get at least 1500 miles before I replace it this coming weekend/next week.


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## JRoque (Mar 9, 2010)

Hey but why the steep change in current limit? If you suspect the battery discharge curve knee gets too sharp with the heavy amp draining, current limiting like you did is great. But I think you went too steep with the motor amp cut and that's why your acceleration is suffering. After all, if you're limiting what you drain out of the battery, having a motor limit that's much higher will get you great low RPM torque (ie: low controller voltage to motor) while still protecting the batteries to the max you already set.

The way I look at the current limits is: battery amps protect your batteries, motor amps protect your wiring/windings. 

JR


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## TheSGC (Nov 15, 2007)

JRoque said:


> Hey but why the steep change in current limit? If you suspect the battery discharge curve knee gets too sharp with the heavy amp draining, current limiting like you did is great. But I think you went too steep with the motor amp cut and that's why your acceleration is suffering. After all, if you're limiting what you drain out of the battery, having a motor limit that's much higher will get you great low RPM torque (ie: low controller voltage to motor) while still protecting the batteries to the max you already set.
> 
> The way I look at the current limits is: battery amps protect your batteries, motor amps protect your wiring/windings.
> 
> JR


I could try it, but I know that I need a minimum of 25.4 KW to travel up these 6-12% grade hills at 35 MPH and that is were most of my problems lie. I usually average less than 180 motor amps and 150 battery amps while accelerating, according to my Zilla DAQ. If I had 144 or even 156 volts of these batteries, I probably would never need more than 180 AMPs peak from them! This afternoon I will adjust it to 500 motor amps and 200 battery amps a see what that does.


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## octagondd (Jan 27, 2010)

What DOD have you gone to on a regular basis? Do you think they can handle 70-75% or better to stick down closer to 50%.


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## TheSGC (Nov 15, 2007)

octagondd said:


> What DOD have you gone to on a regular basis? Do you think they can handle 70-75% or better to stick down closer to 50%.


I usually have been pounding them down to 65-70% DoD each time I went out, 17 miles. I have found the current draw is really what matters. These suckers should be kept under 220 AMPs peak, and with a 144 volt system that is easily doable. I routinely need 265 AMPs for 30-40 seconds at the beginning and end of my commute, and past 50% DoD that voltage sages pretty low, like down to 10.75 volts a battery at 65% DoD pulling 265+ AMPs to climb hills. 

That past few weeks I have only gone down 25-30% DoD around town, 6-7 miles of errands. Since I am replacing this pack in the coming week, I have removed most of the safety current limiting on my Zilla and just have been enjoying pedal smashing my EV. I keep up with hilly traffic no problem, cruising at 85-125 AMPs @40 MPH and I go no farther than 10 miles.


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## Stunt Driver (May 14, 2009)

I have to say NO to MAXX29.
Mine loose capacity after 3-4 months, so 100-120 cycles.
I chanrge CV up to 14.5v.

What is your charge method? Could that be the readon?


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## TheSGC (Nov 15, 2007)

Stunt Driver said:


> I have to say NO to MAXX29.
> Mine loose capacity after 3-4 months, so 100-120 cycles.
> I chanrge CV up to 14.5v.
> 
> What is your charge method? Could that be the readon?


I have a K&W BC-20, old skool charger that will dump 10 AMPs into the batteries until they reach 14.5v, then trickle down to 1-2 AMPs and I shut it off. I have since upgrade to a higher capacity pack, but I still have my MAXX29s, and they are being reconfigured into a dumping station for my EV when I get the time to do it.


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## 84bertone (Apr 10, 2008)

84bertone said:


> Thought I would post an update on the Walmart Maxx 29's that I am using. I have 8 of them in a 2340 lb (total weight) car for 96 volts. Almost all of the mileage is about 10 miles total at any one time with a couple of times out to 20-22 miles. And yes I could go further.
> 
> Based on that type of use, I have recharged them about 40 times over the course of 2-3 months. I recharge them individually directly after each use, with a 6 amp charger.
> 
> ...


Above is my initial post to this thread and this is my final post concerning my experience with the WalMart Maxx-29's.

After about 2.5 years, driving distances of mostly under 10 miles before recharge, and a couple of thousand miles, 2 of the Maxx-29's are done. The others are hardly useable so for all practical purposes the pack is dead. 

I have taken the car off the road for now and will upgrade to Lithium. But not until I can figure out what's what in the Lithium battery business.

By the way, I still have the LogiSystems controller and it still works well. It has never given me any trouble. I do keep it cool with fans. Heat kills electronics.


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## rfhendrix (Jan 24, 2011)

Does anyone think that Trojan batteries will last twice as long? They cost about double so I was just wondering...


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## Guest (Feb 22, 2011)

No doubt about it. Trojan's are not even in the same class as walmart batteries.

Pete


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## rfhendrix (Jan 24, 2011)

gottdi said:


> No doubt about it. Trojan's are not even in the same class as walmart batteries.
> 
> Pete


Thanks. Just for fun, with all things being equal and a Walmart battery lasting 2 years how many years would a Trojan battery last?


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## Guest (Feb 23, 2011)

Problem is there is no all things being equal. Life depends upon how you care for them and how hard you run them and how often and how deep you run them. But I can assure you that Trojans are very high quality and very good batteries. Walmart cheep-o marine 12 volt deep cycle batteries are good for trolling motors on your boat. Period. They are not designed for vehicles like Golf Carts or cars. I used GC2Energizer 6 volt flooded batteries for my Ghia and those are not even up to the standard of a Trojan. Get true Golf Cart batteries and stick with 6 or 8 volt batteries and not the 12. Lead acid batteries will not get you much distance either. Now if you drive the speeds of a golf cart then you may get some reasonable distance. But if that is how you drive then go get a Gem or something that is nice and already done. If you convert and if you at all can go with lithium batteries. 

Pete


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## rfhendrix (Jan 24, 2011)

Right. Now all I need is the money.


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## Guest (Feb 23, 2011)

Thats about what most of us need. In the end lithiums are cheaper. Get good ones.


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## Ziggythewiz (May 16, 2010)

Update on my marine floodies (29DCs): After about 10 months of use they need to be replaced. They have less than half their original range.

Unfortunately, Sams Club tests them for CCAs (these things put out plenty even if empty) instead of actual capacity, so they say they're all in great shape.

Unless you have bad cells or blown posts the 30 month warranty is worthless.


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## Shane Jackson (Sep 28, 2011)

Ziggythewiz said:


> Update on my marine floodies (29DCs): After about 10 months of use they need to be replaced. They have less than half their original range.
> 
> Unfortunately, Sams Club tests them for CCAs (these things put out plenty even if empty) instead of actual capacity, so they say they're all in great shape.
> 
> Unless you have bad cells or blown posts the 30 month warranty is worthless.


That's funny as I have exchanged several batteries over the years at Sam's and I have never had them even test them......


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## Ziggythewiz (May 16, 2010)

Yeah, just depends which idiot you get at the counter.

The first one i took back they didn't test, but it would have tested bad.

The others they've tested with a diagnostic station at one location, and a glorified multimeter at another that supposedly pulls over 800 CCAs.

If you try to replace a bunch at once though, I'm sure someone will test them.


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## MN Driver (Sep 29, 2009)

Might depend on the location you go to, I had a guy at my local Sam's tell me to just bring my battery back a few months before the free replacement period neds and you'll get a new one. I've got a buddy who has done exactly that with the battery in his car. Probably a bit different if you are bringing back a bunch of them or if you've got a receipt with 12 batteries on it and a few are already marked as replaced, or however they do it.

Worse case if they test fine, couldn't you just deep cycle them at the bottom of their SOC range a bunch of times until you know they'll fail?


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## Ziggythewiz (May 16, 2010)

MN Driver said:


> Worse case if they test fine, couldn't you just deep cycle them at the bottom of their SOC range a bunch of times until you know they'll fail?


Guess it all depends on the location. At mine they probably won't fail, ever, without extreme abuse. The tester at the first place was a garage unit, so I didn't see that one run, but at the second they used a handheld unit with maybe 12 or 14 gauge cables and ran a 2 second test that indicated they can put out 800 CCAs. They pass at over 625. I played around with one battery and it could put out over 700 CAs with no electrolyte in it. They don't use a real load test, so even a surface charge is enough to pass.


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