Mother's Batteries are Kaput

[CaliforniaCurmudgeon]

My Mom called because here batteries are kaput. I have not personally checked them and I am ~5 hours drive away.

She asked me to look for replacement batteries. I am looking for advice and suggestions.

I am a complete novice, and don't plan to be the one putting in the replacements.

She currently has 8 6v Deep Cycle batteries. They look like Golf Cart batteries to me. The person helping her today is not an electrician thinks they are wired in two banks of 24v. There is a electrician familiar with solar who comes around and does work in the area, but if he is the only one coming out to you it is $250 travel, and he has been supposed to come look at it when in the area for a while now. When I look at the picture they sent and trace the wires I am not sure they aren't wired together as 48v. The MPPT appears to support both 24v and 48v systems and could support LifePO4 batteries if I read its manual right.

She is running lights, StarLink, TV, smartphone, and refrigerator. Everything else is propane - hot water, stove, and heat. She has a backup generator as well.

My thoughts -

• Replace as like for like as possible - looking at about $2000 from what I have seen. If I recall correctly you aren't really supposed to bring these deep cycles below 50% so of the 10,800 wh she only has 5400 wh usable
• If 24v replace with 1 or 2 24v LifePO4 200AH battery either rack mount or like the current ones but raise them off the ground $1500-2000
• If 48v replace with 1 or 2 48v LifePO4 100AH $1500-2000
• Replace the whole setup with an all-in-one inverter/charge controller/etc and new LifePO4 batteries.

Here are some images:

 

[chrisski]

The is definitely set up 4S2P, I wish the pic was good enough to read the label, but since each battery has 3 caps, I agree they're 6 volts, for two 24 volt batteries.

I recommend replacing them with either the same batteries, or 6 volt deep cycle batteries with the same terminals, or going with a GC2 sized trojan batteries. Same batteries and terminals means the last cables can be reused. Flooded Lead Acids has a few different types of connections, and keeping the connections the same lets you reuse the wires. Clipping and adding connectors takes time and any copper wire needing purchased is pricey.

-The batteries there may not be the best, but there's something to be said about getting Mom's system who is 5 hours away up and running quickly with over the counter parts.
-The Trojan Solar SPRE GC2 Batteries are what I used were a good deep cycle lead Acid batterybut those were not local and were delivered from the next state over. You'd probably need to purchase more of that thick wire at $4.50 - $5.50 per foot, with connectors around $5 per cable, and the crimper is pricey if you don't have it.
-Also, how these batteries died would drive how I got the new ones; if they are abused, I'd go cheaper, but if these last batteries lasted years, I'd lean towards the Trojans.
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The batteries could be wired better. This is a good read:

SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank

The batteries are now wired to pull more power from the bank closes to the left wall on the bottom pic. Putting the red battery cable in the bottom pick on the right bank bottom battery positive terminal would help.
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Possible the batteries could be recovered, but this may be more work than it's worth. Its a lot of work and could be difficult to talk her through. IME a lead acid battery depleted to a low state of charge once could really effect it.

 

[seneysolar]

Thats 24V system for sure.

If nobody is around for regular maintenance, id look at Full River sealed, maybe just 4 of the DC400. You have cable to do 8 but these are 400ah instead of golf carts that are maybe 220ah.

No need for new equipment, you have quality stuff, just keep those cables clean.

DC400-6 (Grp L16) Battery

Get free shipping on Fullriver Deep Cycle DC400-6 Batteries

thebatterydude.com

 

[Rocketman]

The first picture shows the eight batteries, but also shows 2+ at the bottom - are there more batteries?

 

[Rocketman]

If you want to move to lithium here are some things that need looked into:

You need to adjust everything to lithium charging…
The inverter
The Solar Charge Controller
The battery monitor

It is a Magna Sine brands, unfortunately I don’t know much about that brand and if these particular units are lithium compatible- maybe someone else may know.

Also does this area (where the batteries are) ever get below 35 F?

Good Luck