Replacing a lead acid 12v 250Ah battery

Hi,

I am looking for advices on what is the best option to replace a 12v 250Ah lead acid batteryto power an astronomy observatory that has almost only 12v equipment. what would be the preferred approach from your point of view? 4s100p, 7s50p or 13s25p packs? with 2500mAh batteries and does it really worth it if I can find a new lead acid one for $200??

Thank!

Use 4S LiFePo4 (Lithium Iron Phosphate) if you can - that gives perfect voltage replacement for 12V lead acid. Otherwise for Li-Ion Id go with 7s50p with a 24V -> 12V buck converter. Those are readily available.

Thanks!

my understanding is that you cannot really use more than half of the capacity of a lead acid battery without starting to damage it, so if it was a 250Ah lead acid would I have a correct assumption to replace it by a 12V 125Ah li-ion or LiFePo4 battery which will be only 62.5Ah for a 24V 7s pack ?

With Lead Acid, yeah the DoD is about 50%. With LiIon you can go closer to 80% and still be ok.

As far as Ah ratings, I would stay with the 250Ah or close or more instead of going smaller. The reason is because you can get cells with 2500mAh ratings if you buy new and you will get better/longer power life.

LiFePo4 would be better as you'd not need any special buck converter to compensate for over voltage to the equipment.


Does the equipment run on 12V or 24V? I'm guessing 24V.

As far as being worth it. I would say yes. For one, the weight would be a lot less. You can run a long time on battery. And you can charge them back up faster.

Lithium cells apart from LiFePO aren't usable for 12V, so you can either use new lead acid batteries, get a 12V LiFePO battery or use any other lithium battery and a DC-DC converter. If you're on a strict budget then get new lead acid batteries. If you can afford it then get LiFePO batteries.