Parallel 325 ah Trojan bank with 435 ah Trojan Bank: how bad is this idea?

[hammick]

I am buying my neighbor's 48v bank of Trojan L16H-AC batteries (eight batteries). They are 435 ah and I'm getting the interconnects and a nice custom made cabinet. Paying the scrap value of $350. These batteries are approx 3 years old but haven't been babied. I'm going to charge them all separately with a 6 volt 20 amp charger to see if the specific gravities are where they should be.

Our current bank is Trojan L16RE-A batteries 325 ah that are five years old (eight batteries in series). They are in good shape.

This Spring we added a second refrigerator and if I want to run both fridges during the winter I will have to take my 325 ah bank down to 60% SOC or lower which I don't want to do. If the 435 ah bank I am buying are in good shape I will switch to those and probably sell my current bank or keep them on a float charge. If they are trashed I'll sell them for the scrap value.

If I parallel the two banks together will I damage the 325 ah bank? I know this is not recommended or ideal but if both banks are fully charged before I put them together can I do this without hurting the batteries?

I'd like to get five more years without buying batteries and then switch to LifePO4.

Thanks.

[Mike90250]

use a voltmeter and charge both banks to the same voltage, and at that moment, connect them together. No sparks (unless you make a mistake)

Parallel - they will last as long as the weakest battery. You have 3 year old, well used batteries. How long they last, depends on how deep the cycles were and how you treat them in the future. Look to the warranty of the batteries, if they were 3 year warranty, getting 4 or 5 would be great. Getting 5 more years from them now, is iffy in my opinion.

[hammick]

use a voltmeter and charge both banks to the same voltage, and at that moment, connect them together. No sparks (unless you make a mistake)

Parallel - they will last as long as the weakest battery. You have 3 year old, well used batteries. How long they last, depends on how deep the cycles were and how you treat them in the future. Look to the warranty of the batteries, if they were 3 year warranty, getting 4 or 5 would be great. Getting 5 more years from them now, is iffy in my opinion.

Thanks Mike. So it sounds like they won't make my 325ah bank which is five years old but shallow cycles (except for a month last winter when panels were covered with snow) deteriorate any quicker? I'm picking up these 435ah batteries today and charging them to see their condition. Turns out a faulty fridge was the issue with their system.

[hammick]

Got the batteries today. 7 out of 8 were between 6.14 and 6.22 volts. One was in the mid 4 volt range and isn't taking a charge. I think it has one bad cell. I'm going to see what kind of specific gravities I can get out the other 7 before I decide if I will scrap them all or replace the one bad one. Ideally I'd like to find a used 435ah L16 Trojan. I think a new one would just cause problems with the other batteries.

[Sunking]

Got the batteries today. 7 out of 8 were between 6.14 and 6.22 volts. One was in the mid 4 volt range and isn't taking a charge. I think it has one bad cell. I'm going to see what kind of specific gravities I can get out the other 7 before I decide if I will scrap them all or replace the one bad one. Ideally I'd like to find a used 435ah L16 Trojan. I think a new one would just cause problems with the other batteries.

Save yourself a lot of heartache, stop the wallet from bleeding any more, take your loses, learn your lesson, and move on. The batteries were abused causing one too fail already. and the other 7 are close behind.You would just be throwing more money away buying either a new or used cell. Afraid the only happy party in the transaction was the seller. If he/she had traded the cores for new ones would have only received $20 credit for each cell or $160. He/she came out way ahead and did not have to move or ship them. Sounds like you rolled the dice and came up with Snake Eyes.

[hammick]

Save yourself a lot of heartache, stop the wallet from bleeding any more, take your loses, learn your lesson, and move on. The batteries were abused causing one too fail already. and the other 7 are close behind.You would just be throwing more money away buying either a new or used cell. Afraid the only happy party in the transaction was the seller. If he/she had traded the cores for new ones would have only received $20 credit for each cell or $160. He/she came out way ahead and did not have to move or ship them. Sounds like you rolled the dice and came up with Snake Eyes.

The scrap value of these batteries is $350. I'm not that concerned if I have to scrap them. I have pallet forks for my tractor and the scrap place will unload them from my truck. Bought them from a good friend/neighbor so I would have hauled them into town for free had she asked. Plus they bought the $8,000 Eclipse LifeP04 battery and I will get to see if it performs as well as they claim. I'm trying to buy a couple years before I go LifeP04.

[littleharbor]

Last time I scrapped my batteries they were paying 38 cents a pound. I got $38.00 a battery x 8. Pleasantly surprised.

[hammick]

Last time I scrapped my batteries they were paying 38 cents a pound. I got $38.00 a battery x 8. Pleasantly surprised.

Thanks for the info Littleharbor. Was that at a battery place or a recycling center? The highest I've found so far is .23 per lb. and that's only if I scrap more than 3.

[Sunking]

Hammick when you go off grid, money is no object. That is why you went off grid in the first place was to loose money. Start throwing more money at it.You will do that for as long as you are of-grid. Enjoy spending all that money. You do not need it. Ask Bernie and Joe, they will agree.

[hammick]

Hammick when you go off grid, money is no object. That is why you went off grid in the first place was to loose money. Start throwing more money at it.You will do that for as long as you are of-grid. Enjoy spending all that money. You do not need it. Ask Bernie and Joe, they will agree.

Sunking don't be an off grid hater just because you love the suburbs. Some people go off grid to live at the base of the mountains with a good amount of land, wildlife everywhere, and great three season climate. We are those some people.

They will never bring power up here. I made sure of that before I put the solar in. If they did I would sell and buy somewhere else. Power brings people which brings more cars, ATVs, dirt bikes, dust, etc.

I don't know Bernie or Joe but tell them hello.

Now tell me how to safely bring back a dead cell in a Trojan L16 so I can buy a few more years before I go LifeP04. The other 7 batteries are recovering nicely. I already have 4 of them at proper specific gravities.

I dumped the acid out of the dead cell into a clean bucket. Rinsed the cell thoroughly with a hose. Made sure all the water was out and put the acid back in using a strainer funnel. No go. It's still dead. Pretty sure the plates go exposed for an amount of time. The other two cells are at full specific gravity.

I'm not comfortable trying the reverse polarity trick or sticking a copper wire in the dead cell to get it boiling with a charger. I like my eyesight. I might try the epsom salt trick that is all over Youtube. Maybe a NOCO Genius 10a charger with desulphate mode since I could use another charger the toys.

The local Trojan supplier has their eye out for a used 435 ah L16. They agree that putting a new one in with three year old abused batteries is a bad idea.

Sunking it's time you start having a positive attitude. All that negativity is going to put you in an early grave

[littleharbor]

Thanks for the info Littleharbor. Was that at a battery place or a recycling center? The highest I've found so far is .23 per lb. and that's only if I scrap more than 3.

A battery recycling yard.

[Sunking]

Now tell me how to safely bring back a dead cell in a Trojan L16

I can't bring the dead back. I understand your situation. Good luck finding a used one. Tip, it does not have to be a Trojan L16 for temporary band-aids. You just need help crossing the finish line.

Figure out how to get in touch with me. I got an idea for you.

[hammick]

I can't bring the dead back. I understand your situation. Good luck finding a used one. Tip, it does not have to be a Trojan L16 for temporary band-aids. You just need help crossing the finish line.

Figure out how to get in touch with me. I got an idea for you.

Well for the life I me I cannot figure out how to send PM on this site but my email is

Thanks.

Email removed for posters security

[Mike90250]

because of spammers, PM's were disabled several years ago, sorry

[paulcheung]

To OP,
If I were you, I just go and buy 2 new 6volt 225AH golf cart battery and parallel them, and put them with other 7 to help to get few more years if lucky enough.
Cheers.