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Author Topic: Funny Goings On in the Old Tin Battery Shed ...  (Read 9902 times)
Eleanor
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« Reply #15 on: October 24, 2009, 11:52:20 AM »

Merkland, I've been wondering about this as they do seem to be almost mirror images of each other. I woke up this morning and realised I was probably being a bit of a dimwit yesterday with the battery charging. Looking back at the data I think the batteries would have been in float mode and not equalising as the voltage was very quickly at about 14.4V. Fairly obvious really in retrospect  wackoold.

I'm not sure now how I'm going to be able to give an equalisation charge to individual batteries as the only charger we've got that will do 15V+ is the 50A Victron. I suppose I could leave one battery floating on the little 3A charger but I'm not sure I can wait that long on the off chance that it may make a difference.

I'm tempted to try Merklands suggestion and then try an equalisation charge on the whole bank. Or is this a really bad idea? Fortunately it is only a leisure bank so if it all goes wrong we'll just get another eight batteries. I don't feel experienced enough to splash out on the expensive ones yet. We'll be back on wind power shortly so hopefully things will improve.

I'm in two minds whether to do the capacity test now. I suppose I was thinking that if battery 2 really is a dud it would just give up after a while with battery 1 keeping going. Going down this road will inevitably result in having to test all the batteries which which is a lot of work and recharging with only a generator.

Probably best to think a bit more .. thanks to all for their suggestions. Martin they have had hours and hours of bubbling. I measured SGs on the whole bank over 2 hours when they have been bubbling and after the initial rise it makes no difference. Batteries 1 and 2 have each had an additional 3 hours of bubbling but only at 14.5V. The remaining six batteries have been at 30V while I've been charging the individual batteries or the generator has run so they have probably had about ten hours at 30V. I'll go now and have a quick measure of the SGs. It's possible they may have improved while I've been messing about with the other two. It would be good if they have. I'll have a look at the Smart Gauge wiring, thanks. I'm starting to think that the clean slate approach is going to best and then look at the existing batteries when we have more generating capacity.

Justme, thanks for your post. I'm going to check the SGs on the six batteries to see if there has been any improvement. I'll have a look at  making the "good" batteries into a bank. I think it will probably only be a temporary solution. I'm starting to think I'm probably flogging a dead horse ....
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Stuart
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« Reply #16 on: October 24, 2009, 01:22:10 PM »

Eleanor,
looks like you have some a few dodgy cells. They will pull the performance of the rest of the bank down as in parallel they rob charge from adjacent cells to charge themselves.
if you bank is 440Ah 48V on a 20hour discharge rate you will need (440/20*48) just over a Kw of load. Get them connected up and measure each cell voltage while there under load. The dodgy cells will read below 12V
we have the same problems as we use 48 cell strings to get 110V in series the poor cells warm up as there being resistive, often spectacular
Below is a very good website full of information on how to store, charge and discharge different types of batteries
defiantly worth reading thoroughly as charging batteries at high currents and voltages is very bad for them!
there is a charge on charge method for SLA cells and a equalisation charge you can do but as the text should explain it is only for a limited time. and only 100mV more!

http://www.batteryuniversity.com/partone-13.htm
http://www.batteryuniversity.com/parttwo-35.htm

good luck.
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Eleanor
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« Reply #17 on: October 24, 2009, 03:30:49 PM »

Stuart, thanks. Our leisure bank is at 24V and I'm fairly convinced now (I wasn't to start with) that some of the cells in batteries 2, 4, 6 and 7 are duds  Sad after doing the test you suggested earlier. I realised after posting that of course float charge is much lower, I think I've spent too much time in the tin shed and am totally confusing myself! I've only been charging the bank at 15V for about 2 hrs at a time (not 10 hours at once!) and the current is limited by the Victron charger. I wouldn't charge them so often normally but these are desperate times! Having read the info it seems that the 14.5V that the 15A 12V charger was giving the individual 110Ah batteries is enough for an equalisation charge. The more I read about this battery charging lark the more I realise how little I know  Roll Eyes

Anyway, decisions have been made  police I think .... for now .... possibly ... until someone suggests something else ...  facepalm

1. I'm going to take Justme's advice and make the best batteries into a 220 Ah bank
2. Get a new 440Ah bank of leisure batteries  horror to continue practicing on for a few more months. We'll be back on wind power in a few days and a dodgy 220Ah bank isn't going to be good enough. We can put in place a proper regime of battery charging and care before we make the leap to individual cells and a bigger bank. Perhaps as suggested by Billi we have been generally undercharging leading to sulphation in some of the cells.

3. I'm interested to see how the Smart Gauge performs so I think we may have to buy one and set it up against the Victron battery monitor. Presumably when we get a new battery bank in a few months we can wipe the memory?  Huh
4. When we have more generating capacity we can see if any of the "duds" can be revived  fight
5. Buy a temperature compensating hydrometer and measure SG every week - it doesn't take very long to do  stir

6. I haven't looked at the Smart Gauge site yet to see how they wire the bank differently - will do that later on today.

7. Get the battery monitor software so we can log the voltages and currents to get a better idea of how the battery is being charged/discharged. Lots of other things to measure too  police

Thanks to all for help and suggestions  Cool I'll report on what happens later  help
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« Reply #18 on: October 24, 2009, 03:51:28 PM »


2. Get a new 440Ah bank of leisure batteries  horror to continue practicing on for a few more months. We'll be back on wind power in a few days and a dodgy 220Ah bank isn't going to be good enough. We can put in place a proper regime of battery charging and care before we make the leap to individual cells and a bigger bank. Perhaps as suggested by Billi we have been generally undercharging leading to sulphation in some of the cells.

Don't know how much you're paying for the leisure cells, but there are quite a few sets of used forklift batteries being sold on ebay.  Surely those are a better bet than continuing to buy new leisure cells every few years/months?  If it were me, I'd prefer to practice on a rugged old set, rather than a flimsy new one.
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« Reply #19 on: October 24, 2009, 03:55:22 PM »



2. Get a new 440Ah bank of leisure batteries  horror to continue practicing on for a few more months. We'll be back on wind power in a few days and a dodgy 220Ah bank isn't going to be good enough. We can put in place a proper regime of battery charging and care before we make the leap to individual cells and a bigger bank. Perhaps as suggested by Billi we have been generally undercharging leading to sulphation in some of the cells.

3. I'm interested to see how the Smart Gauge performs so I think we may have to buy one and set it up against the Victron battery monitor. Presumably when we get a new battery bank in a few months we can wipe the memory?  Huh

4. When we have more generating capacity we can see if any of the "duds" can be revived  fight

6. I haven't looked at the Smart Gauge site yet to see how they wire the bank differently - will do that later on today.


2, Why spend out on them? Get a forklift / 2v cell set up.

3, Join the canal boat forum & then buy one from canal shop man you might get a discount

4, worth trying but good luck

6, do it soon cos the site "might" be going off soon as they have just been bought out.
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Eleanor
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« Reply #20 on: October 24, 2009, 04:30:05 PM »

Thanks both, I have to say that the forklift option is the one I've been considering as you do seem to get a lot more for each spent. I'll have a look on Ebay and Canal Boat forum. I think if we go for them it would probably be from new as I think I would want to know that we are starting out with a good set. I suppose the reason for buying another set of leisure batteries is that they are readily available and it delays the decision a bit longer (probably the real reason  Roll Eyes). Also, getting things delivered here "from Down South" can be awkward and expensive. I think you are right, we have probably outgrown leisure batteries and I should look in Inverness for forklift batteries and compare the prices with having them delivered from further afield.

Justme, the likelihood of us ever getting around to trying to revive the duds is probably pretty remote in reality. Perhaps I should just flog 'em on Fleabay  Grin
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« Reply #21 on: October 24, 2009, 05:00:28 PM »

"carefully run-in" Grin
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Eleanor
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« Reply #22 on: October 25, 2009, 01:19:32 AM »

"carefully run-in" Grin

I prefer the phrase "Carefully and thoroughly inspected"  police

Personally, I'd go for "give 'em a good bubble" as whole banks a go - charge them right up, and leave them fizzing for a couple of hours, it isn't called an equalisation charge for nothing..... then I'd implement the wiring regime as suggested on the Smart Guage site - it may look messy, but the maths makes a lot of sense.........

Martin, I've had a look at battery wiring on the Smart Gauge site and I have a feeling that we have been there before. I could be wrong but I think we are Method 3 and I do recall TSOM wittering on about the importance of getting all the wires the same length.

http://www.smartgauge.co.uk/batt_con.html

I've been having a think about Stuart's post and I'm beginning to come to the conclusion that part of the problem is due to overcharging as three of the failed batteries are connected to the positive bus bar. When it first happened I did have visions of buckled plates and shorted cells. I imagine that the fourth one which was connected to the negative bus bar just died of something else or couldn't live without the others. Or more likely was murdered like the rest of them but just in a different way stir It just makes me glad that we found all this out on a leisure bank  Grin. I think we've covered most ways of killing a battery bank, if anyone has any other suggestions we'll be pleased to oblige  Roll Eyes
« Last Edit: October 25, 2009, 01:05:47 AM by Eleanor » Logged

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Alan
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« Reply #23 on: October 25, 2009, 08:08:50 AM »


Quote " I think we've covered most ways of killing a battery bank, if anyone has any other suggestions we'll be pleased to oblige  "



You could also top them up with salt water.
Batteries will then give off Chlorine gas.

Best to make a new home for the Dog & Cat first.

Regards

Alan
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Stuart
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« Reply #24 on: October 25, 2009, 09:33:16 AM »

Yes get a bank of series conected high capacity cells if you can.
Shame i didn't get that job as a UPS engineer the other month, that could have be 'useful'
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« Reply #25 on: October 25, 2009, 06:16:59 PM »

Just came home 2 minutes too late these Solar cell batteries   went for EUR 2,05 on an ebay auction http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&item=250511870835

12 cells C10  600 ah two years old  and two cells not good , others still 2.1 volt

 banghead banghead banghead banghead banghead

If the transport and logistics would be easier i would buy all of these occasions

Billi

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Eleanor
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« Reply #26 on: October 26, 2009, 10:53:42 PM »


Quote " I think we've covered most ways of killing a battery bank, if anyone has any other suggestions we'll be pleased to oblige  "



You could also top them up with salt water.
Batteries will then give off Chlorine gas.

Best to make a new home for the Dog & Cat first.

Regards

 
Alan

Good one. Not one I'd thought of. Have you tried it?  Shocked I imagine that accidentally dropping the baking soda you were keeping handy for spills into the cells wouldn't help much either. I suppose you would be able to replace the electrolyte if you knew the SG when it happened stir I think I may give both of those a miss!

Billi, if you see anything "suitable" I'd be interested. I think you know the problems of logistics where you are. Stuart, UPS engineer sounds like a good job. I imagine you would find a lot of cells needing replacing, I just can't think what you would do with them all  Roll Eyes
« Last Edit: October 26, 2009, 10:56:33 PM by Eleanor » Logged

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« Reply #27 on: November 05, 2009, 07:53:58 PM »

Sorry to hear of your battery woes Eleanor...  I started out with 4x 110Ah leisure batteries all in parallel but converted to 24V so that I'd only have two strings in parallel and they have been ok at balancing.  Then I got a deal on some gel 180Ah 6V batts and so now I've only got a single series string so shouldn't have any serious balancing probs.

When I upgrade again, I'll probably go for 12x used 2V cells.  I can't lift more than about 40kg by myself and if you get 2V cells you can swap out duff ones more easily.

I wonder if anyone's tried a NiMH pack from a crashed Prius from a scrappy...  You'd need a special charger but you wouldn't have to worry about killing the cells by over-discharge.  They are 201V 6.5Ah.
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« Reply #28 on: February 20, 2010, 07:52:52 PM »

hi i have just installed a new forklift battery from Hopecke 24v 625ah C5 with aqua tops central filling system and air lift electrolyte mixing system cost 2050euros delivered, food for thought
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« Reply #29 on: March 08, 2010, 12:23:27 AM »

Eleanor
I think the equalisation charge is a good place to start, many forklifts do a full-charge and then an equalisation charge afterwards every time.

It could be sulphate. Interesting that the batteries aren't very old. Last year I bought a small battery for a quad, obviously not banked but stick with me, it was supplied with the acid in a bottle and vacuum stoppers in the breathers. I followed the flooding instructions to the letter, charged it at the correct rate, everything looked fine so I installed it. Then, after a couple of days, it wouldn't start the machine. On re-charge the voltage went to a silly level above the 13.9v expected. I couldn't explain it and neither could the supplier. To all outward appearances the battery looked like it was old!! Anyway, my guess was that the plates had sulphated or oxidised.

Here's the punch line, and there is a cure, I charged the battery for a short time (1 hour) each morning and left the lights on (no engine) for less time each night for several days. Low-and-behold, the battery improved and would hold its charge much longer. Then, over time, under normal use, it has come up to spec. Possibly yours may have a similar complaint.

There's all sort of cures for cleaning plates - high frequency or pulse circuits - but I have no experience of these. Some say anti-sulphation tablets work well - I don't know, and they look a bit pricey to me.

Banked batteries are a pain but they are necessary. In your position, I would want to see each battery performing correctly for a while on its own out of the bank. Then, when all is ok, join them up again and keep your fingers crossed. I think there is more art than science where batteries are concerned!

Guy

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