# BIG FLA overcharge and following waterloss



## jockepocke (Nov 24, 2009)

I put my kelly charger in "balanced"(equalize)-mode last night, left it overnight, and checked batteries this morning, only to find them really hot (the hottest about 50°C) and with massive waterlosses. The batteries are insulated in my car as the weather is -15°. I could smell sulphuric acid fumes. According to the charger manual, the charger should shut off to prevent battery damage in this mode, but apparently this does not seem to have worked here. (At least I think that is what they say, their English is terrible...)

Fortunately, the cells which lost the most water still had just enough to reach the top of the plates, but only just enough. In the worst cases the plates were probably ~1 mm above water level, but the surface tension keept them wet. No dry plates that is. 

I filled up the batteries with distilled water, but had just not enough water, so the last batteries got a little less than the others (still well enough water in all of them now, though).

My questions are: May there be any damage to the batteries, eg loss of acid, or damaged lead plates, or maybe overtemperature? 

Should I avoid driving until I have filled up water in the last cells to the same level as the others?


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## yarross (Jan 7, 2009)

jockepocke said:


> My questions are: May there be any damage to the batteries, eg loss of acid, or damaged lead plates, or maybe overtemperature?


High temperatures and excessive charging may make your positive plates prematurely get worn.


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## jockepocke (Nov 24, 2009)

yarross said:


> High temperatures and excessive charging may make your positive plates prematurely get worn.


Ok, that is expected! But you do not think there is any direct damage done? That I need to refill acid etc? Or can I just drive as normal?


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## Guest (Feb 1, 2010)

Doubtful you need to replace acid. What you lost was water, not acid. Some may have been lost but very minimal and usually not enough to even notice with SG testing. Fill them up and keep going. What's up with the charger? Maybe you should check all your cells too. 

Pete


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## Guest (Feb 1, 2010)

Check the SG in each cell is what I mean to check.


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## rmay635703 (Oct 23, 2008)

Check all your battery voltages before going on your trip (specific gravity is best if you have a hydrometer), if one battery/cell is quite a bit lower best to take it out of the string and do a discharge/recharge test on it individually. 

If nothing seems dramatically out of the ordinary Perhaps drive a bit less distance on the next trip and monitor the charger on the next charge, keep a multimeter honed in on it to see what voltage your pack is seeing, if the voltage is OK it is possible one of your cells is shorted out which will quickly wear out surrounding batteries.

Also for future reference, If you check inside the batteries right after the bubbling starts up good and strong (unplug charger first) you can visably see what cells aren't charging, also you can check the SG of the cells with a hydrometer 

Good Luck
Ryan


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## dtbaker (Jan 5, 2008)

just one overcharge, without driving dry, probably no big lasting damage..... fill to correct levels ASAP with distilled water while its fully charged.

Consider installing a watering system to make watering easy and consistant, and ya gotta figure out why that charger didn't shut down. If you have a couple batteries showing significantly lower than the rest, the charger may not have hit the high v trigger and just kept charging...

how many cycles do you think you have on the pack? at what average %DOD? What kind of batteries?


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## jockepocke (Nov 24, 2009)

The batteries are traction (deep cycle) FLA, manufacturer Crown. The charger is made for deep cycle FLA. The batteries are quite new, probably only about 10 cycles, at maybe 50 % DOD. 

In normal mode the charging works fine, and the system voltage is 120 volt. At full charge, without float charge, the pack will reach 127 volt, as supposed to. 

I have filled every cell, there seems to be approximately the same waterloss in all cells, which I consider is an indication that they are all OK. I will check each batteries voltage, but I have no hygrometer. May there be any problem with a different water level in some cells (I will have more distilled water tomorrow to fill up them all)? I know the dilution will be different according to water level. 

I also checked bpt of sulphuric acid, 279,6°C (with water at 100°C) so, as you said, probably no acid was lost. I could, however, smell acid fumes. 

I do not think there is anything wrong with neither charger nor batteries, I have read the manual for the charger some more times, and it seems there is only a time shut off in the balanced charge mode, after 12 hours. As the batteries were quite well charged I reckon they just got too much power... Seems like I will have to monitor every equalizing charge from now on. 

I recommend Kelly to write a new manual though, almost impossible to read... "When can accept the voltage rise to the battery when highest voltage then entered the sixth section of constant voltage to charge..."


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## dtbaker (Jan 5, 2008)

it is 'normal' to have some acid fumes after a equalization charge when the batteries 'gas' a little... but that stage should NOT last 12 hours. Typically, after a CV stage when amps have dropped off to 1 or 2, and 3-stage curve may set an 'equalization' voltage but should drop back to a trickle as soon as it is reached.

After a few more cycles you'll have a good idea how many kWhr you have to put back in per mile, and you might wanna plan your charge times so you can be around when the charge SHOULD be ending...

And a word on checking SG; I have yet to hear a good reason for doing this rather than MAYBE just checking individual voltages once in a while to make sure one battery isn't completely out of line with others signaling failure. You're not supposed to add acid EVER, so why bother checking it?! Just make sure the water levels are good.


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## MN Driver (Sep 29, 2009)

dtbaker said:


> so why bother checking it?! Just make sure the water levels are good.


The reason to check specific gravity is that voltage can lie and SG is the ideal way to determine state of charge. Sometimes it can help identify issues that voltage won't find, such as if your expected voltage and specific gravity don't seem to coincide the way they should it could mean you have acid stratification causing the voltage to appear higher than the real state of charge is and the undercharging will damage the cell over time.

In most cases it isn't necessary and getting away without it is something pretty much everyone here does as voltage is usually 'good enough' for most people. I don't use flooded since my small scale stuff is AGM and only 36 volts, so I don't really get the choice as my cells are sealed but I'd check if I had around ~12 floodies at least once and awhile to make sure nothing is awry but then again I check tire pressure even though it stays above minimum spec for months at a time for me since I go a little over spec in the first place, that's just the way I do things.


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## jockepocke (Nov 24, 2009)

Ok, I just checked the battery voltages. The lowest is at 12,68 V, while the highest is at 13,07 V. (Biggest difference is 0,39 V.) The higher voltages were recorded at the batteries that have a little less water than the others. Can there be any connection? These batteries are probably better insulated as well. 

I will fill up water to the same level in all of them, drive some kilometres to get rid of the surface charge, and check voltages again to see if there are still fluctuations.


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## rmay635703 (Oct 23, 2008)

jockepocke said:


> Ok, I just checked the battery voltages. The lowest is at 12,68 V, while the highest is at 13,07 V. (Biggest difference is 0,39 V.) The higher voltages were recorded at the batteries that have a little less water than the others. Can there be any connection? These batteries are probably better insulated as well.


Yes that is a sign your batteries are out of balance. Good idea to keep them watered properly not too high, not too low.

Something not usually mentioned here is that FLA batteries are like tires you inflate tires, you rotate tires and if one tire is flat you can't drive.

If your batteries are in fairly dramatically different positions that result in significant heat variations it isn't a bad bet to rotate them every 3-6months. Those of us who have logged more than 5 years on a pack usually have done more maintenance than normal and depending on how you do it, maintenance can definately result in better battery life.

I don't believe in being extremely anal when not warranted but when you notice a problem it is definately warranted to keep on eye on everything and determine where the fault is. In my case when I found one low battery in my string last year and one next to it with a low cell; I kept a voltmeter honed on just the "bad" set to determine my new max range. I then did discharge and desulphating cycling on that pair when I had time. Those 2 came back somewhat, but then one next to them started having the same behavior. Needless to say very old packs can become more work than they are worth.

But if I didn't keep an eye on the batteries that were drifting further and further down my pack would have had to been replaced early last year instead of this year.

Perhaps if I would have been more vigilant I may have gotten one more year but on one trip I decided to get home as opposed to save the pack and that did in 6 of my 9 batteries, they still work but are at very low capacity now. Ah well.



jockepocke said:


> I will fill up water to the same level in all of them, drive some kilometres to get rid of the surface charge, and check voltages again to see if there are still fluctuations.


Good idea


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## MN Driver (Sep 29, 2009)

Since the acid content doesn't go down when the water level is lower, the water/acid mix is more acidic with less water, which does have an effect on voltage.


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## jockepocke (Nov 24, 2009)

Ok, so now the batteries have hade the same water level for a couple of days, and I have driven short ranges. I measured voltages this morning. The batteries were fully charged and had some floating charge left. I applied a 4 amp load to the batteries during the whole testing (the motor field). The highest charge was now in one of the batteries up front, at 12,88 v. The lowest charge was found in one of the batteries that previously had one of the highest, and was at 12,76 v. The maximum difference is 0,12 v. Is this an acceptable difference? Compare this to the difference of 0,35 v maximum before. 

Will I get a more accurate measurement if I drive some kilometers to remove the floating charge, then let the batteries rest for a while and then measure?


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## jockepocke (Nov 24, 2009)

Ok, this is not good at all. I just drove a bit today, and noticed a sudden serious voltage sag, from 120 to 88 or something. I went home and checked the batteries. Most of them were between 12,4 v to 12,6 volt, however one battery was down to 10,35 v and two other to 11,5 v and a fourth to 11,0 v! How could this have happened? They were balanced before... 

Is it possible that I got some bad batteries? I noticed some of them were quite discharged and needed some water when I got them... 

And what do I do now? I have plugged in the charger, and when it indicates full battery I will run equalizing charge for about an hour or so... What more should I do? The batteries had a temperature above +15°C.


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## dtbaker (Jan 5, 2008)

jockepocke said:


> Most of them were between 12,4 v to 12,6 volt, however one battery was down to 10,35 v and two other to 11,5 v and a fourth to 11,0 v!
> 
> Is it possible that I got some bad batteries? I noticed some of them were quite discharged and needed some water when I got them...


this is not sounding very good....
Were these all *supposed* to be new batteries from the same batch? Sounds like some were old or sitting on the shelf for a long time.

You could try some 'manual equalization' by using an external 12v charger on the low batteries independantly to get them up even with the others.


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## jockepocke (Nov 24, 2009)

dtbaker said:


> this is not sounding very good....
> Were these all *supposed* to be new batteries from the same batch? Sounds like some were old or sitting on the shelf for a long time.
> 
> You could try some 'manual equalization' by using an external 12v charger on the low batteries independantly to get them up even with the others.



I do not really know about the condition, but I assumed I would get good batteries as I bought them first hand from a company. I got them driven to my house. If the same batteries remain in bad condition I will call them. 

I was thinking about manual equalizing, but I only have a 2 A charger... Better than nothing at least.

Is this something I can fix, by trying to check and equalize the batteries, or will I always have some bad cells?


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## dtbaker (Jan 5, 2008)

Sounds like you got some old batteries from a different batch.... which would also explain the initial long overcharge at equalization voltage if the pack voltage couldn't quite get up to where it needed to be to 'finish'; the older batteries couldn't accept the charge and the newer ones boiled....

I'd try manual charge on the low batteries , then charge pack.... try a couple cycles. If the same batteries are low, then replace them sooner rather than later so that your OTHER batteries aren't mismatched with the replacements too badly.


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## jockepocke (Nov 24, 2009)

dtbaker said:


> Sounds like you got some old batteries from a different batch.... which would also explain the initial long overcharge at equalization voltage if the pack voltage couldn't quite get up to where it needed to be to 'finish'; the older batteries couldn't accept the charge and the newer ones boiled....
> 
> I'd try manual charge on the low batteries , then charge pack.... try a couple cycles. If the same batteries are low, then replace them sooner rather than later so that your OTHER batteries aren't mismatched with the replacements too badly.



I have charged the weak batteries with a separate charger now, and driven a little bit. It seems to ok until a certain point. Fully charged the batteries have quite similar voltages, but only when discharged this big difference is visible. I have been told this is likely because some batteries are weak, and can deliver a much lower amp-hours than the others, thus discharging faster (so the voltage difference is only visible when discharged). 

I will run some more tests to see if these batteries are constantly weak. If so, I will demand new ones from the company. 

Can I save a bad battery somehow, or must I replace it?


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## rmay635703 (Oct 23, 2008)

jockepocke said:


> I will run some more tests to see if these batteries are constantly weak. If so, I will demand new ones from the company.
> 
> Can I save a bad battery somehow, or must I replace it?


I would demand new ones before taking the HUGE effort of fixing up a battery. Generally fixing batteries is best left to folks who like to tinker with the batteries more than use their EV.

If it turns out you absolutely cannot get the battery replaced and you are willing to do a lot of maintenance due to imbalanced batteries, there are a few things that ssslllooowwwly bring back sulphated batteries.

First you need to check the troublesome battery, generally most every 12v battery failure is a shorted cell, which is NOT repairable without extreme effort and even then very likely to fail again if fixed. To check for shorts get the troublesome battery up to equalizing voltages and visually see if all the cells are bubbling, if one is not, likely its failed, same goes if you check SG and find one is much lower.

If all cells function, you have a few choices, 

the most hands off is to run a multiple sets of hard & heavy charge and discharge cycles to try to blow off sulphation, these can be accompanied by a pulse desulphator (or use a desulphator alone like alastairs) to speed up this process.

If that is not an option, you can dump the acid (drain it all out and save)
Then fill with plain distilled water and trickle charge until the SG of the water stops increasing (sulphation dissolves in plain water) Again this process can be sped up using a pulse desulphator or EDTA
Once the sulphation is dissolved, dump the distilled water and save it for adding to batteries with weak cells.
Next step is to bring up the SG of the acid you drained to the stock SG recommend by the manufacturer, generally acid from a weak battery will be weaker than required resulting in poor range and possibly freezing.
Add the acid back in once at the proper SG, do a slow charge, discharge and repeat several times to set the battery. It should perform like new

PS the method above is actually from the US government.

There are also other things you can do if your lazy but they don't work well and cause problems with your battery.

I know because I have done most every one of them, my trojans have almost no lead left in them and are failing due to simple decomposition! But I have a feeling I have the most miles on any T-875 in this group 

Good Luck
Ryan


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## jockepocke (Nov 24, 2009)

Ok I just checked the bat batty while charging. Every cell was bubbling at least. I have talked to the company, and they agreed to give me new batteries if they are bad. If I cannot fix this battery soon I will have them run a load test on the bad batteries, and if it is indeed bad and not just undercharged for some reason I will have new one(s) for free. 

I have charged the bad one with a 2 A charger some days now, I will drive the car with a voltmeter on the bad one to see the voltage drop compared to average. 

Always nice to be dealing with a nice company!


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## jockepocke (Nov 24, 2009)

I have not been active for a period of time now, and I apologize. Has been alot to do in my private life, and starting university has taken som time too... 

Anyways, I have contacted the Swedish company that sold me these bad cells, and after a couple of months of arguing they agreed to test them all. Apparently they were indeed bad, and they have sent them back to the manufacturer, so I will have to wait even further before I have them back. But with good batteries my range will hopefully increase from about 6 km to 30 km. I have also bough 10 individual chargers @1 A to keep them balanced. 

*The extensive gasing of the batteries during the overcharge was most likely due to bad cells in some batteries! *


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