# Battery popping (short?) question



## Duncan (Dec 8, 2008)

Hi Nobrush

I suspect that you have reached the end of your cells life 
Lead acids have a life - then they die 
Most people get about 18months!

Its probably time to take your car off the road and do a bit of work on it,
As an engineer you should be able to get up to speed pretty quickly

First job is to do an inventory - what have you got? - what is working fine?

Then make up a plan 
(1) - Just get it going - probably replace the batteries check the wiring
(2) - Make it better

5 years ago Lead Acids were almost the only game in town, Lithium is now affordable, much lighter, and lasts a lot longer


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## dougingraham (Jul 26, 2011)

Sounds like you have a shorted cell in one of the Lead Acid batteries. This was probably why your charger was not shutting off. Lead Acid have a short life. They are expensive for the life you get out of them but cheap up front. Shorted and open cells are common failures for Lead Acid.

Measure the voltage of each battery and you will probably find the one that is sick is the same one you are having problems with although you might find that you have several that are weak. You can sometimes remove the sick battery and install a jumper across where that battery was and continue to use the car at a reduced range and performance level but you will need to make changes to the charger and sometimes the motor controller.

I would suggest you replace them with lithiums. If you give us the particulars of the car we can suggest a course of action. By particulars, what does it weigh (what kind of car), current pack voltage and battery type, motor/controller/charger range requirement (not pie in the sky range but what you really need.)

Best Wishes!


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## nobrush (Jan 23, 2014)

So first off- you guys are awesome- I'm stoked that there's so much quick feedback that I was contemplating just trying to sell the car as is but now I'll try and stick with it with a bit of research. I'd like to limp it along at first if possible as my company just got bought out and they only kept a few of us (i got really lucky) so who knows if that is longer than 2 years even though they tell us it is. 

The spec's- 
-96 Geo metro- 3000lbs as it lies now; converted with lead acid (the rear seats were removed, headliner, etc. to lighten it and frame was beefed up a little also) 
-Kelly 96V/12A Charger HWC4B (it did blow a integrated 20amp fuse which I replaced with a fuse holder that comes out of the vent grate for easy access and was probably due to that battery going out) 
- Motor D&D ES-31B 72-144 VDC Series Wound Single Shaft - 12hp Cont @ 96 Volts -not sure if it's brush-less (I've been told not to have it at 400 amps for very long so I try and keep it under 300)
- Kelly controller- KDH09501- 24.96V 500A stamped on side - booklet states "10 sec. boost 500 amps, 1 minute current 400A, continious current 200A, Nominal voltage 24V-96V, Max. oper. voltage 18-120V
- (16) 6V Crown 20Hr rate 245 deep cycle lead-acid batteries making up a 96V system (I can get used 6 volt batteries for $55 here in town but it sounds like that may not be the best idea from what you're saying)

I live 12 miles from work but there are some hills- the biggest is on the way home there's about a 1000' road I need to climb- I am able currently charge for free at home (flat rate electric bill) and at work which helps

I'd like to try that jumper idea that I'm guessing mean I can just skip over that battery and have a 90V system? I thought it might damage something in the system but if you say it's ok I'm game to try at this point. I don't mind reducing my range a little bit as when I get home I have about %70-%80. 

I'm interested in pricing the LiPo's but that sounds like I'd have to put in a different controller & charger which is probably another $1000 on top of the Lithium pack.

I'm currently charging up the back with multiple 12V chargers at 2amps double up the batteries in series- then I'll let it sit for a day and then measure voltage to see which ones are strong and weak although currently all I know is 6.45V is full-


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## madderscience (Jun 28, 2008)

prior posters are right, your lead acid batteries are likely DOA.

FWIW, I am not sure Deionized water and Distilled water are the same thing. you want to add distilled water to FLA batteries. Deionized may not be what you think.

In San francisco there has got to be an active EVA (electric vehicle association) chapter. Find and join them to get some hands on feedback.

With a conversion, You have got a bit of a mental challenge living on top of a hill, as it requires you to ensure you have a certain amount of oomph left in the tank in order to make it home, as you can't coast home on fumes (so to speak) like those of us who live in a valley. you will need to figure out how much energy you need to climb the hill, then develop the discipline to not try to get up that hill unless you know you have enough power left. A production EV will shut itself down before things are damaged, a conversion may not. Ensure your car has the instrumentation to know exactly what your battery capacity is, how much you have left, and how fast you are using it. Any modern BMS will do that, and you will need a BMS with lithium anyway.

Your Geo will probably lose 500 pounds or more going to lithium, depending on what the setup is now. I'm basing this on the presumption that the car without batteries probably weighs in around 2000lbs. 

While saving up for the lithium plunge, go through every part of the high voltage and high current system and look for bad connections, undersized wires, loose or corroded connections, and any short cuts the builder/prior owner made. Any one of these could also be causing erratic contact. You will have to redo a lot of this anyway going to lithium.

Typically with LiFePO4 lithium, half the weight of lead acid will give you double the range that the lead acid gave when new, with the bonus weight reduction. If you started out with a 120V, 200AH lead pack, a good lithium replacement would be a 120V (or 144v if your controller will take it) of 130AH cells. It is always good policy to run the highest voltage pack you can which the controller will handle. Make upgrades elsewhere as needed to accomodate. You will need a new charger most likely anyway with lithium; most other costs should not be too much.

Good luck.


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## Duncan (Dec 8, 2008)

Deionized water should be the same as distilled water 
(as far as batteries are concerned)

BUT - that assumes that the ion exchange resin used was OK
On the other hand I have seen some very dubious "distilled water" 

Either should be OK if it is from a decent source and not contaminated before use


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## dougingraham (Jul 26, 2011)

nobrush said:


> I'd like to try that jumper idea that I'm guessing mean I can just skip over that battery and have a 90V system? I thought it might damage something in the system but if you say it's ok I'm game to try at this point. I don't mind reducing my range a little bit as when I get home I have about %70-%80.


Removing one 6v battery will lower your voltage by ~6 volts. This will reduce your theoretical range by at least 4% because you have removed 4% of the energy you are carrying around. The range reduction will be a little worse than this because you will be pulling more current from the batteries to make up for the loss in voltage and higher currents will decrease battery efficiency. You may notice that it seems to run out of power in a particular gear sooner. This is because of the lower voltage. On the other hand you have been driving it with a bad cell which can cause worse voltage drop than you will see by removing one battery. We won't know until you try it.

As far as the controller is concerned the battery will look like a partially depleted pack. The voltage will be a little low. If there is a setting for low pack voltage to protect the battery then it will trigger early and stop you from driving out the full range. I don't know anything about the Kelly controllers so that is just a comment.



nobrush said:


> I'm currently charging up the back with multiple 12V chargers at 2amps double up the batteries in series- then I'll let it sit for a day and then measure voltage to see which ones are strong and weak although currently all I know is 6.45V is full-


If you remove one battery you will have an odd number so you will need a 6 volt charger for one of the batteries. Maybe your chargers have a switch to select 6V.

If it were my car I would upgrade the pack to the maximum voltage the controller will allow. You indicated 120 volts so this is probably equivalent to about 36 lithium cells. If the 245 is AH on your 6 volt batteries then you probably get about half that in actual use with a 1 hour rate. This means your existing pack is 11.8 kwh. A pack that size on a 3000 lb car would give an estimated range of 39 miles when the pack is brand new. You should only use half of that at most if you want the pack to last even 2 years so consider the actual range to be about 20 miles. If you put in a pack of Lithium cells using 60AH cells you would have 6.9 kwh. Since the vehicle is going to be around 800 lbs lighter with this smaller pack of lithiums this would give an estimated range of 31 miles of which it is safe to use about 80% so this makes your actual usable range about 25 miles and it should last at least 8 years and probably more than 10. Probably the only thing you would need to buy apart from the batteries is a new charger. My preference would be to use 100AH cells which would give you an 11.5 kwh pack and an estimated range of 46 miles and recommended range of 37.

As always your mileage may vary.

Best Wishes!


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## nobrush (Jan 23, 2014)

That's amazing if I can get 8-10 years out of a set of batteries- that's what I"m talking about. It's economical then and cheaper than gas, which isn't the only reason I'm doing this obviously but it makes my cheap side happier. So can I charge the pack with one or two batteries less without damaging the charger? I'm thinking about take 2 batteries out, and am not too worried about driving the pack "into the ground" so much at this point. I was going to buy replacement batteries but it seems like that money would be better spent on switching it over into LiPo4. I just want to make sure that I don't mess anything up in the meantime. It is cool if I could use the same controller though.


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## nobrush (Jan 23, 2014)

Just to clarify- It's a 96 volt system. From what someone else said, I should need around 30 LiPo4 batteries.


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## dougingraham (Jul 26, 2011)

nobrush said:


> That's amazing if I can get 8-10 years out of a set of batteries- that's what I"m talking about. It's economical then and cheaper than gas, which isn't the only reason I'm doing this obviously but it makes my cheap side happier.


Yes. If I drove 30 miles per day instead of only an average of 12 my savings compared to gasoline would pay for my batteries in a little less than 3 years instead of 6 years. I get about 30 miles per dollar spent on electricity. When the car was ICE powered I got 5.33 miles per dollar spend on gasoline. Long term Lead Acid are not cost effective conpared to Lithium but still cost effective when compared to gasoline.



nobrush said:


> So can I charge the pack with one or two batteries less without damaging the charger? I'm thinking about take 2 batteries out, and am not too worried about driving the pack "into the ground" so much at this point. I was going to buy replacement batteries but it seems like that money would be better spent on switching it over into LiPo4. I just want to make sure that I don't mess anything up in the meantime. It is cool if I could use the same controller though.


My impression was that you are using separate 12 volt style automotive chargers and charging pairs of 6 volt batteries to get 12 volts. How could removing one 6 volt batter damage the charging of the other 14 (7 pairs)? The only change would be charging the single 6 volt battery. And you would need a 6V charger to do that one.

If you meant damaging the speed control, then the answer is no, you wont hurt it. The controller will operate down to 18 volts from your specs.


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## nobrush (Jan 23, 2014)

Sorry, I must not have mentioned it earlier in this post- but I have an onboard Kelly 96V charger. I just was at my dads and was trying to figure out a way to pull less energy thru one outlet as I partially melted one of his plugs. I think it was because the cord had a bad connection and haven't had issues after fixing it. So my question is, will I damage either the engine or the onboard 96V charger when using a battery pack with less batteries than it was originally designed to run on?


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## dougingraham (Jul 26, 2011)

Unless you can turn down the output of the Kelly 96 volt charger to an appropriate voltage for the reduced voltage battery you will be trying to cook the batteries. The charger will never turn itself off. I can't see any other thing at risk here. If you have been using this charger with a shorted cell it probably was not turning off and trying to overcharge the batteries. Look at the charger manual and see if there is a way to adjust the output voltage to match the 90 volts.


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## nobrush (Jan 23, 2014)

So there's no way to change the voltage output of the charger. I was wondering if just to try and get by for now, while I research LiPo4 a battery pack conversion, if I can put in a used 220rate battery when the rest are 245 rate (both are 6V deep cycle) in the pack without damaging any of the electronics?


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## dougingraham (Jul 26, 2011)

nobrush said:


> So there's no way to change the voltage output of the charger. I was wondering if just to try and get by for now, while I research LiPo4 a battery pack conversion, if I can put in a used 220rate battery when the rest are 245 rate (both are 6V deep cycle) in the pack without damaging any of the electronics?


This will not be optimum but I can't see there being any risk to the electronics, just the batteries. Mismatched batteries are not a good idea but your batts are already not in the best of shape so I don't see this as being an awful thing to do to tide you over for a while.

Good Luck!


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## crackerjackz (Jun 26, 2009)

dougingraham said:


> This will not be optimum but I can't see there being any risk to the electronics, just the batteries. Mismatched batteries are not a good idea but your batts are already not in the best of shape so I don't see this as being an awful thing to do to tide you over for a while.
> 
> 
> 
> Good Luck!



I second this 100 % ..


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## nobrush (Jan 23, 2014)

So I'm guessing the reason they're not a good idea is because of the efficiency of the pack right, not safety issues?


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## dougingraham (Jul 26, 2011)

nobrush said:


> So I'm guessing the reason they're not a good idea is because of the efficiency of the pack right, not safety issues?


When the batteries are all new and the same they all behave the same. You charge them up and with Lead Acid you have a top balanced pack. As long as you don't discharge more than about half of the weakest cell you will do well. When you mismatch stuff you still charge up and have a top balanced battery. But different manufacturers batteries behave differently so you can kill a different battery by accident. It probably doesn't matter because the pack is already questionable. When you have one battery fail there will be others not too far behind. The replacement battery is a different manufacturer and age and it could be far better than the other batteries in the pack or it could be worse. With used stuff you can't tell. If you can get the car back on the road for a couple hundred dollars and it suits your needs then do it. Start saving for a Lithium upgrade. Right now it costs me about 1/6 of what it would cost if I was buying gasoline. And that is with gas at about $2.80 per gallon. You don't have to drive too many miles to pay for the batteries with the savings from not buying gasoline.


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## nobrush (Jan 23, 2014)

Thanks Doug, I figured as much. Can you suggest any good places to research Lithium batteries, brands that you think are quality, conversions from Lead to Lithium, etc? I think someone may have mentioned it
but I'm guessing I can still keep the controller.


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## dougingraham (Jul 26, 2011)

nobrush said:


> Thanks Doug, I figured as much. Can you suggest any good places to research Lithium batteries, brands that you think are quality, conversions from Lead to Lithium, etc? I think someone may have mentioned it
> but I'm guessing I can still keep the controller.


Look at the wiki. Check out the Vendors on the right side of the screen. Check out EVTV.ME videos and store.

There are several threads where people have swapped out to lithium. You can read through those.

I would increase the voltage to the max the controller will handle. Probably 144 volts. This would be a max of around 42 cells. To be safe maybe just use 40 cells. Your vehicle is going to be around 800 lbs lighter when you switch to lithium unless I have misjudged what you have for lead acid. It will also take about 1/3 the space so you will get some storage space back as well.

If I was doing this today I would use the CALB CA100 series cells (Grey case) and I would buy them from the EVTV store because they come with the inter cell straps and stainless bolts and special lockwashers. Not having to screw around buying all the extras bits you need anyway saves a lot of hassles.

Best Wishes!


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## nobrush (Jan 23, 2014)

I found the EVTV.ME site, but I looked up http://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery and there isn't any vendors on the right side of the screen. Is that the wrong link?

What is the purpose of maxing out the controller (or close to it), just to max out range? 

My round trip is 24miles with a hill, so I don't need the most range, but I'm guessing they degrade a bit over time like lead but not as much.


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## Duncan (Dec 8, 2008)

nobrush said:


> What is the purpose of maxing out the controller (or close to it), just to max out range? .



Hi,
Your controller acts as a power in - power out device

150v battery x 100amps battery = 15v motor x 1000amps motor
(for starting - as the motor revs build you need more motor volts)
150v battery x 300amps battery = 45v motor x 1000amps motor
(at about 1000 rpm ish) 

This means that for any condition increasing the battery voltage *reduces* the battery current

Which is a good thing for battery life and also for losses


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## nobrush (Jan 23, 2014)

So I tried to put in a refurbished battery but it was charging at 8+ amps when everything else was charging correctly. Due to this, I think I've decided to give up with lead acid as I don't want to fry that battery quickly. Now it's time to figure out lithium

As far as having 40 batteries, vs. 30, I appreciate your input & what you're saying, but there has to be a point of diminishing returns right, or am I missing something? At the rough price of about $130/piece (not including shipping), that's $1300 more (or %25 more) when I don't need the range. From what people have said on here, is that the batteries will last about 8-10 years. I'm wondering how much longer that will help them last, and even if it does, that far down the road I'm guessing that the technology will get much better/cheaper as it has in the past 5 years from what it sounds like. 

I could be totally off base- but that's my impression.


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## dougingraham (Jul 26, 2011)

nobrush said:


> So I tried to put in a refurbished battery but it was charging at 8+ amps when everything else was charging correctly. Due to this, I think I've decided to give up with lead acid as I don't want to fry that battery quickly. Now it's time to figure out lithium


You need to balance all the parts of your battery. The new battery will be at a different state of charge from the old portions. Charge all the parts individually before you assemble it in to a pack so the state of charge of all the pieces is the same. After that you might see some difference in voltage because the replacement battery is a different brand or even just a different age but for the most part they will arrive at full charge at about the same time.



nobrush said:


> As far as having 40 batteries, vs. 30, I appreciate your input & what you're saying, but there has to be a point of diminishing returns right, or am I missing something? At the rough price of about $130/piece (not including shipping), that's $1300 more (or %25 more) when I don't need the range. From what people have said on here, is that the batteries will last about 8-10 years. I'm wondering how much longer that will help them last, and even if it does, that far down the road I'm guessing that the technology will get much better/cheaper as it has in the past 5 years from what it sounds like.
> 
> I could be totally off base- but that's my impression.


40 cells gives a nominal voltage of 128 volts.

30 cells gives a nominal voltage of 96 volts.

What you will experience is a limited torque band. About 3/4 as wide as with the higher voltage. This means you will have to shift sooner and will limit the top speed in the highest gear. This also affects the load on the batteries when the motor RPMs are low. This is because the controller and motor work as a team. The higher voltage at the battery is converted to current at low RPM. The battery is under less stress in all driving regimes except for when the motor controller is on 100%. This usually is a short period of time during hard acceleration. You would be better off keeping the 40 cells (128 volts) and reducing to 60AH size cells to cut your costs. The downside of 60AH cells is that your battery current should be kept to an average of around 180 amps. You can exceed this for a few seconds at a time going up to 600 amps. With 100AH cells this average current would be 300 amps and the peak current on the batteries would be 1000 amps. Your controller won't do that anyway.

Now it won't hurt to get 30 cells today and drive the car. You can always add in the extras later.


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