Tips for rejuvinating tired lead acid batteries

[MB]

My Trojan T-125 lead acid batteries have been getting weak for a while. Over the past couple of nights, my car hasn't been plugged in at night so the batteries have been allowed to go cold.

The car was plugged back in yesterday but it looks like five out of eight of my batteries have pretty much given up the ghost. After three miles of driving, the voltages were down to 1-2v on five batteries

Anyone got any tips on what I can do to rejuvinate them and get them firing on four cylinders again, or is this the end of the road for this set of batteries?

[ChrisB]

Really depends how many cycles they have done Mike

If they have reached the end of their life then they have reached the end of their life I'm afraid

You might find keeping them warm will extend them a tadge, I've heard that some folks have torn up old Electric blankets and removed the heating wires out of them and used them as Battery heaters, I took an old blanket apart once took me ages and was a real fiddle.

Might be worth trying to keep them warm during the charge cycles and thus during the discharge cycle ??

Theres loads of "dope's" and other such electronical gadgets out there but I've not ever seen any of them work on batteries that have become terminal due to their cycle life being all used up.

Me thinks as its Christmas a nice set of Li-po's are order of the day

ChrisB

[MB]

They've done 612 cycles, although the vast majority of those are from around a 50%-60% SOC.

Lithiums are out of the question with my finances at the moment though. I was considering buying a donkey and converting the G-Wiz into a trap...

[ChrisB]

Not sure about the donkey idea think of the smell

mmm 612 isnt that many really but then not knowing how hard they have been worked its hard to say, if your pulling current out of them above their C rating then it wouldnt surprise me if they have started to keel over

Tricky one really, I presume they are all nicely watered up and you have CHECKED this and not just gone on the auto watering device I think the G-wiz uses ??

So what are we saying you've got about 18k miles out of them working on an average of say 30miles per cycle ?? not bad really. be intersting to see what your recharge costs are and the cost of the batteries orginally and then add them together and find the equivilant if you have been using petrol/deisel ?

I did that some time ago with my Fiesta and it actually worked out more expensive but then fuel was a lot cheaper then and I only worked on 500 cycles.

There was a chap on here that was doing something with pulse rejuvinators I seem to remember, he was in Reading I think ?? but I feel thats only any good if they are suphated, I feel yours could be due to lose of active material

Always the worse bit when the batts die in EV's, but you have to remember its like buying all your fuel up front

ChrisB

[MB]

I've had around 6,500 miles use out of the batteries. I have been checking the water levels reasonably regularly and I'll be pulling the thing apart tomorrow to have another physical check. Every time I have done this in the past the water levels have been up as high as they should have been.

I'm trying to find out the C ratings for the Trojan T-125s. The G-Wiz tends to pull 110 amps out of the batteries when cruising flat out with up to 368 amps peak.

I must admit, I'm wary of going for another set of Trojans because they don't seem to have been as reliable as the batteries used in earlier G-Wiz's.

[ChrisB]

Trojan ratings are here http://www.trojan-battery.com/Products/T-1256V.aspx

Looks they are 195 @ 5hr so you are really working them outside their range.

This is always the problem I've found its very hard to keep batteries in EV's within their rated output I think this is where Li-ions win is they are able to supply much high outputs.

Takes me back to the old Bedford CF vans with their Chloride 205's in them, their average @ 30-40mph was about 30-40amps due to it being a 216volt system and thus would fall within the 40 odd amps of the 205's.
I think this was why the vans seemed to go on for so long and that even if you dug one out of a field you could still recover 40% capacity out of the batteries, sheerly due to the fact the batteries where never worked that hard. Then again it did carry a ton of them

Be interesting to see what the specific gravity is like on the dead cells and the others , I'm not sure how the auto watering works on the trojan/G-wizz , I dont suppose theres any risk of it "washing" the electrolyte out of the cells ?? or doesnt it work on a through put type system ?

ChrisB

[MB]

Well, I didn't get as far as checking the watering system this afternoon.

I went out to the car and took it for an 18 mile drive. One of the other members of the G-Wiz Owners Club has written a piece of software to interrogate the Curtis Controller and show what is going on with the batteries. I ran the software whilst I was driving. It warned me when I was overstressing any one of the batteries, or the entire pack, which meant I could back off momentarily and allow the batteries to recover.

I've now put the batteries on another equalisation charge and I'll water it again tomorrow morning. From past experience I know that this process normally gets the batteries back up to speed again, so hopefully I'm over my wobble!