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paul-f asked

Recommendations for Battery Upgrade - Lead Acid to Gel

Hi, hope you are all well? I am looking for someone to point me in the right direction of how to approach and where to find some upgraded batteries for my off-grid system please.

I have a BlueSolar MPPT 150v / 70A, Quattro 48i/10000/140 inverter and 20 batteries that I'm told provide 11.98 amp hours at 48v. Also have a CCGX that I use for (basic) remote access.

At present there aren't any issues with the batteries and they seem to keep their charge as well as they have ever done, but they have been in a few years and when I bought this place I knew they would need replacing sometime.

Any help and advice on which batteries to get and where to get them please? I don't have a limitless budget but don't want to do it on a shoestring as I want them to last.

Also, would there be a need to amend / upgrade any of the existing kit if and when the batteries were replaced?

Someone who works on a large hydro project suggested to me that gel rather than lead-acid would be the way forwards.

Any help, advice or general shoving in the right direction would be much appreciated.

Please note though, I inherited this system and I far from a novice let alone an expert, so it will have to be in words of two or less syllables if I am going to grasp it!

Very much appreciated.

Paul (UK)





48v batterylead-acid
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2 Answers
Paul B avatar image
Paul B answered ·

These days only install Lithium Phosphate batteries

you only ruffly need 1/2 the number of batteries as you can discharge these by 90% without damage (in comparison fo LAs) and there cycle life is way way more.

cost wise when you take into account only 1/2 the qty is needed for the SAME usable stored power they are usually cheaper

and thats if you cycle the LAs you currently have to 50% SOC if you are gental with your LAs and only go down by 20% SOC - then you really only need 1/4 the number /size of LiFePo4 Batteries

Myself I would never use LA style of batteries in a OFF GRID system these days


do the sums and your research on battery types The Quattro is compatible with the LiFePo4 batteries.

There are SO many other advantages of LiFePo4


There recharge time discharge and power allowed, there are just massive differences

IE here is just one

discharging any Lead Acid Battery by say 100A/Hrs then you have to add back 125 A/Hs to refill it and that usually take min 4hrs

With LiFePo4 you take 100 A/H out and only have to put back 105 A/H this can be done in 30min or less depending on charger and bank size

thats a 20% savings or 20% more solar you get all for free - Let alone generator run time considerations if applicable






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marekp avatar image marekp commented ·

I would add that LA battery needs to be kept in well ventilated room because of the hydrogen emitted during charging.

LiFePO4 battery is much safer in that regard.


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seb71 avatar image
seb71 answered ·

I would also say to look into LiFePO4.

But first do some research about them, so that you better understand what would you need (in terms of capacity, manufacturer, etc.) and what the limitations are.

Also, if the existing batteries are still providing the required energy, normally I would say to wait with the replacement. But now that all the money printers go brrrr, it might be more prudent to not wait much longer.

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