# I hate floodies



## racunniff (Jan 14, 2009)

Grr. While watering the volt914's batteries today, I noticed something strange. Since it is hot outside, I was wearing shorts instead of jeans. Anyway, as I was wiping up some spilled water on a battery, my leg happened to brush up against the license plate and I felt the Tingle of Doom. "How weird" I thought. And then did it on purpose to see if it would happen again. Yep. So, I broke out the voltmeter and found a +55V potential difference between that battery and the licence plate. "Oh, crap" I thought. "A worn out wire somewhere." 

So, I traced back the string of batteries. +47V, +39V... +4V (!). That's not a multiple of 8! Going to the next battery got me -4V as you would probably guess. This battery, as all of them, has a patina of battery acid on top (I had not yet gotten around to watering and cleaning it). I wiped the top of that battery down very well, and still had the 4V difference. So, just on a hunch, I put the positive terminal of my voltmeter on the *plastic* on top of the battery. And, sure enough - a 4V potential difference between the plastic top and the car body! 

So, my theory is that perhaps somehow the plastic has become impregnated with lead/sulfuric acid mix, and acid dripped down the side is creating a current path to the chassis.

Any thoughts? This is likely to accelerate moving to either AGM or LiFePo...


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## Tesseract (Sep 27, 2008)

racunniff said:


> ..
> So, my theory is that perhaps somehow the plastic has become impregnated with lead/sulfuric acid mix, and acid dripped down the side is creating a current path to the chassis.


The plastic isn't getting impregnated with acid or lead or anything else, the acid is simply leaving a conductive trail from one or more terminals to the vehicle chassis. This is just a fact of life with flooded cell batteries. It's not a big deal on a 36V golf cart; it *is* a big deal on a 120V+ EV. 

A lot of the bad habits in the EV world came from practices in the golf cart world that are tolerable because of the much lower operating voltage.


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## etischer (Jun 16, 2008)

are you sure it is not ac voltage from your charger that you are feeling, it may not be isolated from ground


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## racunniff (Jan 14, 2009)

etischer said:


> are you sure it is not ac voltage from your charger that you are feeling, it may not be isolated from ground


Yes, I'm sure - it was not plugged in at the time. Plus, the fact that the voltage changed going up & down the battery pack was pretty convincing


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## racunniff (Jan 14, 2009)

Tesseract said:


> The plastic isn't getting impregnated with acid or lead or anything else, the acid is simply leaving a conductive trail from one or more terminals to the vehicle chassis. This is just a fact of life with flooded cell batteries. It's not a big deal on a 36V golf cart; it *is* a big deal on a 120V+ EV.
> 
> A lot of the bad habits in the EV world came from practices in the golf cart world that are tolerable because of the much lower operating voltage.


Hmm. So far, I've just been wiping the tops of the batteries off when I water. Clearly inadequate. Any suggestions on techniques to completely remove the conductive path? I think I saw someone suggesting a baking soda solution...

I've already filled the bottoms of the boxes with baking soda, FWIW.

At this point, despite the cost advantages, I am not recommending flooded batteries to any DIY converters. AGM with BMS (zener diode regulators and individual battery monitoring) at a minimum.


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## Tesseract (Sep 27, 2008)

racunniff said:


> Hmm. So far, I've just been wiping the tops of the batteries off when I water. Clearly inadequate. Any suggestions on techniques to completely remove the conductive path?...


Try wiping down the battery tops with a baking soda solution (not much - say a few teaspoons dissolved in a cup of hot water) rather than plain water. Another idea I had at about the same time as Amberwolf here, is to try running a bead of silicone caulk around the perimeter of the cell caps to create a "dam" to trap any spilled acid. Or perhaps around each terminal... this is more or less an adaptation of the much more messy practice others do of smearing vaseline around the caps, but with no tendency to melt and/or trap dirt.


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## rillip3 (Jun 19, 2009)

Are the batteries getting too warm? I'm not sure what the climate or conditions are like there, maybe it's setting in the sun, etc. and that's causing the bubbling? 

Have you considered just putting a rubber or absorbant mat or the like between the battery and the frame? It doesn't solve the battery issue but you won't get shocked anymore.

It might be a good idea to try and hook up the pack so that it can come out in a block for servicing. I realize it's probably too late for that now, but in the future or for someone else's conversion, making it so you can take out the batteries easily for watering seems like it would avoid this issue as well.


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## rfengineers (Jun 2, 2008)

What you are experiencing is a fact-of-life when living with FLA batteries. The caps are vented and when the batteries are charged or discharged a cloud of acid forms around the caps. Over time this mist will deposit more and more electrolyte on the top and sides of the battery. The result is a low current path to the car body. To keep things under control in my EV I remove all the batteries and wash them down with a weak basic solution every 6-weeks or so. If anyone else has figured out a better maintenance method please share it with the rest of us!


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## jaspersk (Jun 26, 2008)

rfengineers said:


> What you are experiencing is a fact-of-life when living with FLA batteries. The caps are vented and when the batteries are charged or discharged a cloud of acid forms around the caps. Over time this mist will deposit more and more electrolyte on the top and sides of the battery. The result is a low current path to the car body. To keep things under control in my EV I remove all the batteries and wash them down with a weak basic solution every 6-weeks or so. If anyone else has figured out a better maintenance method please share it with the rest of us!


I read a story on EVDL of a guy being able to see small sparking on the tops of the batteries in pitch dark due to battery acid on the top of the battery conducting current. As a newbie this worried me, so I painted all of my battery tie downs with Glyptal 1201. It is insulating paint primarily use in the motor repair business. It is not super strong unless you can bake it on but it insulates well.

Fortunately, I have been running my car for 4 months now and haven't had much battery acid out on the top of the batteries. When I fill them, I don't go all the way to the top but I check them often enough to make sure they never expose the lead plates. I suspect that is why I haven't had much acid on the top of the battery. Is this easier to manage by just not filling your batteries so high?


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## rfengineers (Jun 2, 2008)

jaspersk said:


> I read a story on EVDL of a guy being able to see small sparking on the tops of the batteries in pitch dark due to battery acid on the top of the battery conducting current. As a newbie this worried me, so I painted all of my battery tie downs with Glyptal 1201. It is insulating paint primarily use in the motor repair business. It is not super strong unless you can bake it on but it insulates well.
> 
> Fortunately, I have been running my car for 4 months now and haven't had much battery acid out on the top of the batteries. When I fill them, I don't go all the way to the top but I check them often enough to make sure they never expose the lead plates. I suspect that is why I haven't had much acid on the top of the battery. Is this easier to manage by just not filling your batteries so high?


I'm not talking about fluid coming out of the vents. That is abnormal and usually caused by overfilling the cell. I am referring to the acid mist that always forms around the top of the battery. As far as I know this is normal for any vented FLA cell.


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## jaspersk (Jun 26, 2008)

rfengineers said:


> I'm not talking about fluid coming out of the vents. That is abnormal and usually caused by overfilling the cell. I am referring to the acid mist that always forms around the top of the battery. As far as I know this is normal for any vented FLA cell.


I don't know but my batteries are almost always dry. There is no mist that I can see. If I take a cap off while they are gasing, I will get tiny droplets up on top, but as long as the cap is on, I don't see that. Maybe I am not watering mine enough?


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## JRP3 (Mar 7, 2008)

I know many people have successfully used floodies, but they aren't my style, too much hassle. AGM or lithium for me.


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## rfengineers (Jun 2, 2008)

jaspersk said:


> I don't know but my batteries are almost always dry. There is no mist that I can see. If I take a cap off while they are gasing, I will get tiny droplets up on top, but as long as the cap is on, I don't see that. Maybe I am not watering mine enough?


The mist is not normally visible. There are special tools made, usually using ultraviolet light, that can can be used to see the cloud.
Check with your battery manufacturer about water levels in your cells. Mine (US Battery) says to keep the level about 1/4-inch below the plastic tab inside the cell. If you look inside one of my battery's cells you will see a split plastic "collar" extending down towards the plates. There is a "bump" or tab at the bottom of the collar. The fluid level should be about 0.25-inches below that bump.


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## Guest (Jul 13, 2009)

Gotta be the type of charging going on. My charger works perfect and the tops of my batteries are also dry. Also seems like maybe the tops are off while charging too. Can't understand why the tops would be so wet unless the caps are leaking and much of that is from splashing around while driving and not from charging. Also don't over fill your batteries. Just thinking about all this. 

Pete


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## 86Honda (Apr 15, 2009)

Reducing the water level in the cells helped my shorting problem some, as did tightening the caps well. But acid still spit out of the vents eventually, causing the short. Using battery mats and plywood to isolate the batteries didn't help - the current always found a way. Washing them down with baking soda water would help for a while. I let them air dry before charging and that left a residue of baking soda on the battery tops, which also helped some. Now I am getting internal shorts in the batteries, so replacement seems to be the only answer for that.


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## idoco (Nov 19, 2008)

Someone on the EVDL list suggested using Windex. It has ammonia in it which neutralizes the acid.

I had a similar situation where I traced it to one battery. Wiped it down with Windex and solved the problem.

Another way to prevent the problem is to make sure your batteries are in insulated battery boxes that prevent any path to ground. 

Idoco


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## racunniff (Jan 14, 2009)

idoco said:


> Another way to prevent the problem is to make sure your batteries are in insulated battery boxes that prevent any path to ground.
> 
> Idoco


Good advice. Unfortunately, mine *are* in insulated battery boxes. But acid will find a way...


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## jaspersk (Jun 26, 2008)

I checked my car when I got home. If I lick my fingers and touch the most positive terminal and ground, I get a small shock but it only lasts for a fraction of a second. I can hold my finger on but the shock doesn't continue. It is sort of like discharging a capacitor. If I lift my finger for a few seconds and touch the post, I get the same small short shock. My Fluke reads almost the full pack voltage but I only measure a continuous 0.070mA when I short the most positive to ground with the Fluke. That is pretty much nothing, but still something. The most negative battery to ground gives me nothing. So I disconnected the power cable at the most negative battery thinking it was in the controller or charger. However, I still read the same 0.070mA from 120V terminal to ground even with my most negative battery completely disconnected.

I tried cleaning the terminals on the first 6 batteries and it dropped to 0.065mA but that might just be measurement error.

A question for the original poster would be whether that small tingle continued or did it go away. I guess I am seeing the same phenomena even though I thought my battery tops were dry but it really isn't that bad of a short. It just seems bad because the car acts a bit like a capacitor but really there is still pretty high resistance there. I am not sure that small of a current matters but I'll continue to monitor it more closely now.

I have been considering grounding my pack to the chassis through a resistor and monitoring current in the resistor so I would have an alarm if a ground fault occurred. (Many manufacturing plants have high resistance grounded systems with alarms so they can continue to run if a motor develops a dead short to ground). Maybe I'll move that idea up on the priority list of things to work on.


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## racunniff (Jan 14, 2009)

jaspersk said:


> A question for the original poster would be whether that small tingle continued or did it go away. I guess I am seeing the same phenomena even though I thought my battery tops were dry but it really isn't that bad of a short. It just seems bad because the car acts a bit like a capacitor but really there is still pretty high resistance there. I am not sure that small of a current matters but I'll continue to monitor it more closely now.
> 
> I have been considering grounding my pack to the chassis through a resistor and monitoring current in the resistor so I would have an alarm if a ground fault occurred. (Many manufacturing plants have high resistance grounded systems with alarms so they can continue to run if a motor develops a dead short to ground). Maybe I'll move that idea up on the priority list of things to work on.


The tingle continued. I like the ground fault alarm idea - do you have a set of components in mind? This seems like a good idea even in a non-flooded EV (you hate for your first indication of a ground loop to be an electrocution...)


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## ZEVUtah (Apr 10, 2008)

racunniff said:


> Grr. While watering the volt914's batteries today, I noticed something strange. Since it is hot outside, I was wearing shorts instead of jeans. Anyway, as I was wiping up some spilled water on a battery, my leg happened to brush up against the license plate and I felt the Tingle of Doom. "How weird" I thought. And then did it on purpose to see if it would happen again. Yep. So, I broke out the voltmeter and found a +55V potential difference between that battery and the licence plate. "Oh, crap" I thought. "A worn out wire somewhere."
> 
> .


I 2nd the comment on how I hate floodies. When I looked at your web site I saw that the batteries are in plastic boxes. I would have thought that would prevent them shorting out to the car body. 

Are the tie down straps insulated. I wrapped my tie bars with 3 or 4 layers of heavy tape. 

One other thought is the Zivan charger. I started out with one of these and switched to a Rusco recently. My water usage is now much less than with the Zivan. I check the water level monthly and it seems water usage is only about 1/4 of what it used to be.

Nice looking car by the way.

KJD

http://www.evalbum.com/2058 
http://www.zevutah.com


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## Coley (Jul 26, 2007)

I got rid of all the watering/cleaning crap, when I went to Gels.

So much better and a lot less work. Now I have to just dust them off once in a while.

Mounted a small voltmeter on one battery, with double face tape, to monitor the 14.4 or so charging rate. Everything is as dry as a bone....


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## dtbaker (Jan 5, 2008)

ZEVUtah said:


> One other thought is the Zivan charger. I started out with one of these and switched to a Rusco recently. My water usage is now much less than with the Zivan. I check the water level monthly and it seems water usage is only about 1/4 of what it used to be.
> http://www.zevutah.com


caught my eye.... I have a Zivan charger, but don't really seem to have much mist or water use. I only have had to add 1/4" of water every 3rd month. My rear box which is enclosed does seem to build up a slimy condensation of some kind, but it doesn't appear to affect anything.

I wonder if the rusco does less or fewer over-voltage balance cycles?


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## Tesseract (Sep 27, 2008)

FWIW, I pulled this from the EVDL:



> To: Lee Hart,
> 
> About a month ago I posted a message about acid spills grounding out my
> charger. You suggested the following:
> ...


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## speculawyer (Feb 10, 2009)

racunniff said:


> Any thoughts? This is likely to accelerate moving to either AGM or *LiFePo*...


Go LiFePO4. I'm really starting to think that lead-acid batteries are just really not worth it for EVs anymore.


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## dtbaker (Jan 5, 2008)

speculawyer said:


> Go LiFePO4. I'm really starting to think that lead-acid batteries are just really not worth it for EVs anymore.


based on what? cost analysis?
near as I can figure the 'cycle cost' of FLA for a 10kWhr pack is about $2.25 with the amortized cost of pack replacement after 700 cycles, and the Li would be closer to $5/cycle at 3000 cycles.... not even counting the extra cost of BMS up front.


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## JRP3 (Mar 7, 2008)

Seems as if a lot of floodies don't even make half that many cycles.


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## dtbaker (Jan 5, 2008)

JRP3 said:


> Seems as if a lot of floodies don't even make half that many cycles.


we'll see.... I couldn't find many or any 'real life' reports on how long a full pack of matched floodies last if treated well and usually discharged 50% DOD for instance.....

nor could I find any ACTUAL use cycle reports on current Li chemistry....


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## JRP3 (Mar 7, 2008)

I wouldn't think there would be any real world life cycle data for LiFePO4, none should have come close to the end of their life yet.


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## dtbaker (Jan 5, 2008)

JRP3 said:


> I wouldn't think there would be any real world life cycle data for LiFePO4, none should have come close to the end of their life yet.


I wonder when the 'currently available' chemistry and manufacture design from Thundersky and others came on the market and was first put in an EV? You think it was that guy in AU? I am wondering when we can expect to start seeing end-of-life stories....


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## Guest (Jul 22, 2009)

dtbaker said:


> I wonder when the 'currently available' chemistry and manufacture design from Thundersky and others came on the market and was first put in an EV? You think it was that guy in AU? I am wondering when we can expect to start seeing end-of-life stories....


Hopefully not for some time to come! If we start hearing of end of life now it would kill any chance lithium would be successful. Rumors abound so watch the real world info as it comes in. That is the best we can do or expect. If you decide to jump on the band wagon more power to you and we all hope those will last the full expected life and hope for even better. 

Pete


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## Guest (Jul 22, 2009)

dtbaker said:


> we'll see.... I couldn't find many or any 'real life' reports on how long a full pack of matched floodies last if treated well and usually discharged 50% DOD for instance.....
> 
> nor could I find any ACTUAL use cycle reports on current Li chemistry....


Well cared for may last up to 5 years at 50% or less discharge. Lead batteries can last a bit but you must be ready to do some work. Like the old VW's, you need to do upkeep. 

Pete


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