4 trojans, 2 died, why??

[nothing to lose]

As I mentioned before, I have a battery bank at a remote house and one in my truck. I been charging the one in my truck while driving or at the main house using the grid.

Ok, about a week ago, (the day I drove to Grizzly and got my lathe/mill combo) I charged the truck bank for about 300 miles, or about 6 hours (plus extra). This was about 3 hours,  a few minutes here and there, then 3 hours again, spread out over about 10-12 hours. Not just all at once.

The truck bank is 4 large trojans, about 345 amphrs each, 6 volt. These are wired 2 for 12volt, and both sets of 2 are connected for 12v also. Before starting my long trip I had ran these all a little low charging the bank at the remote house.

My charging methode was simple, jumper cables connected to the first set and the other end to the truck battery. Now all the way there I was watching the amp gauge in the truck, nice good charge being sent. Driving around up there was good charging, and driving home was decent charging though I was running the heater and headlights, plus the batteries should have been getting pretty well charged by then anyway.

No problems then. The next day though I had a dead battery and the truck would not start. Hmm, that was strange, nothing was left on, I still had the cables for the trojans connected also. I should have had about 700amphours reserve on the trojans.

 Well I jumped off the truck, it started, amp gauge showed charging well, and after it ran for awhile I shut it off and it would start up again fine. About 4 hours latter it was dead again. Hmmm.., So I disconnect the cables from the trojans, jump the truck, connect a 40amp smart charger to the trojans. In a few minutes running the truck has plenty of juice to start on it's own and no more problem. The trojans I let charge about 24hours and they showed taking a 2amp charge when I disconnected them (the charger showed 41amps when I started). I have 2 other trojans in the truck (seperate) and I charge those with the smart charger till it shuts off as full.

 Now yester day after all this charging I go to the remote house and connect to the inverter. Dead Trojans, the set of 4! What the heck, my inverter doesn't even see them being there. Ok I connect the other set of 2 and all is well, I have power till late today.

So now I get home and dig out the 50amp load tester and start testing. Nothing has been connected to the set of 4 for over 24 hours now. I first notice hissing (before I do anything), I pop caps looking at water levels and I got batteries bubbling like crazy, water is fine. So I pull the wires connecting them and test. Each set has one battery full charged and holds strong with a 50 amp load tester. Each set has a 4V battery and of course that does not hold any load. These are also opposite ends of the sets. In other words it the first battery in the set on the left, the second battery in the set on the right.  So what I actually have is 2 sets of 10volts each??

What could have caused something wierd like this? These are recycled trojans from a scarp yard, not new ones. But I have been getting great service from them, and now this. The battery in my truck is fine and it would have been the first to get currant from the altenator so I don't think it was that I burned them out overcharging. Also they all got the same amount of bouncing or what ever on the 300 mile drive.

Any ideas?

I will rewire the sets and do some more testing and probably pulse charge the 4v ones again and such, but I found this to be rather strange.

[wooferhound]

What current does your truck charge at

Could possably be, that your truck is charging them to fast and causing the failure...

[nothing to lose]

I don't think that would be it. My 12V truck battery is doing just fine, I would think the trojans wired for 12V would withstand more abuse than a normal auto battery? And I would think I would fry all 4 of them if that were the problem. If these had total capacity it would be near 700amphours for the trojans at 12V also compared to what ever little amount the 12V truck battery would be.

I just got home now and rewired the batteries. Each of the 2 sets had one battery above 6V and one battery at about 4.5V when I just checked them now. So I put the 6V together and hit the 50 amp tester on them, they are holding that load fine it seems. They both hold well as 6V and also together as 12V. Course 50amps isn't that big a load really.

I put the 2 dead ones together and they showed about 10V

I put the charger on them at 40amps, I heard hissing nearly soon as I turned it on.  I took the caps off and I had lots of bubbling in most the cells. I only did that for a minute or so. I set it to 2amps, looked like bubbling and also at 10 amps. Right now I have it pulsing them, I'll see if they come back.

Really curious why that happened.

I have the neg and pos in the center jumped to make the 12V the way they were wired. Then the outer negs are tied between the two sets and the outer pos are tied to connect them. One set it was the battery with positive connection that went dead, the other set it was the battery with the negative connection that went dead. The jumper cables were connected to just one set, outer neg and outer pos.

It's not like I was going neg of one set and pos of the other set with the cables, both were on the same set and the other set was connected to the bolts and wingnuts of the first set.

I suppose I could see frying the both in first set, or all four batts total in both sets, but just the opposite one in each set I don't understand at all!

Hopefully these 2 will come back, but at least I still have the other two working it seems anyway.

[nothing to lose]

 I will check the trucks volts also, not sure what it is.

[halfcrazy]

you say all 4 batteries are tied together for 12 volt but you only hook the jumper cables across the first to not something like positive of the first set and negative of the second set? if all four batteries are hooked together then you should be charging to the 2 corners as to charge them even. i would quicker say the truck alternator may be to big for the 2 trojans what make and model truck is it any idea the output on the alternator? regular car batteries are made for very large current draws and replacements. deep cycles are very touchy about there input amps

[RobC]

Sounds like each battery had a borderline bad cell and they both died on the 300 mile trip. RobC

[wooferhound]

I was just thinking that you bring them down to lower voltage than your truck battery would ever go. Then your truck alternator could be bringing them back to fast.

I'm not exactly sure about what you are doing there. sounds like you have two battery banks. you are using one bank at a remote house, and the other bank is being charged in your truck. Then every so often, you exchange the banks between your house and your truck to keep them charged.

When you put them into the truck, are you hooking up the drained batteries right in with the charged truck battery. Isn't there a tremendous spark when you hook them together like that ?

[RP]

Lead acid battery's don't like to be jostled around too much.  If they were sitting loose in the truck where they could bounce around a bit they might've had some of the material knocked off the plates.  A car battery will always last longer on a car or tractor if its secured.

I think this is the most likely reason for having two batteries fail on the same trip.

[nothing to lose]

Sort of but not exactly.

I have the truck batteries charged and when I get to the house I connect jumper cables to the set at the house. Drawing from both banks at once, also if they will equalize any from the full charged truck ones to the lower charged house ones that happens too since I don't have much load normally at the house. Most of the time it's just about 100 watts of screw in CFL lights (3-5 lights at 15 watts power), sometimes tools and a frig maybe a radio, but not always. Then at night or before leaving I often connect an inverter to the truck bank and run a charger to the house bank to top those off.

I never get any sparks when I connect anything with the jumper cables. I think normally nothing is too deeply discharged, though the house is now.

[nothing to lose]

I been planing to wire them in permanant, have all the stuff not the time.

I would think the way these are wired would be the same as running the pos to a junction bolt and the negs to a bolt and connecting cables to the bolts. letting each battery take what it wants, if these were 12V batteries and they are wired as such.

Perhaps I get the isolator installed I will try negative of one set and positive of the second set. But then I do have a third set, I just didn't have them wired up now.

I think these are Trojan L16p or something like that. I read the label yesterday, 360amps  @20 hours and 299amps @ 5 hours. So 4 Wired for 12V that should be 600amps @ 5 hours. I read charging rates should be low but recharging at the rated amp hours for discharging should not hurt them. I'm sure I did not exceed the 5 hour rating, probably not even close to it.

The truck is a 84 ford F250 351 W (I think), not sure the altenators amps.

[nothing to lose]

Possible, I had them strapped in so they could not slide around or fall over (these are tall thin, not short fat). Maybe I bounced them around a bit too much. But the trip was pretty smooth road, especaily compared to the dirt roads getting to the remote house and back.

I have these pulse charging again now. Been about 18-24hours I geuss so far. Latter I will try charging them up and see what happens and post back on if it worked.

When I changed them around yesterday I had about 10V when I wired the two bad ones together.