I'm looking to upgrade to a 48V solar system as I plan to install eight 430W panels, which makes 12V impractical for future expansions. I've found some cost-effective 48V battery options, like rack mount 100Ah batteries for between $600 and $850, but I also have the option to buy 16 raw 330Ah cells for around $1450, which would leave me some budget for a decent BMS.
While 12V batteries in series seem cheaper (four 280Ah LiFePO4 batteries for just under $1200), I'm worried about balancing issues with that setup. I've read mixed opinions about using battery balancers, as many claim they drain power and don't really do a great job. So now I'm wondering whether it's better to go with 12V batteries and employ an active balancer or just strip the cells to create a 16S 48V configuration with a dedicated BMS.
If you have any experience with this or insights on battery balancing and the benefits/drawbacks of making my own battery, I'd appreciate your advice! Thanks!
4 Answers
When it comes to using 12V batteries, definitely make sure they can handle being in series for a 48V system. Not all of them are suitable for this, especially if the BMS isn't designed for that voltage. If you decide to make your own battery pack, remember to compress the cells correctly and house everything in a metal enclosure. Also, using the appropriate fuses and ensuring the terminals are torqued to specs can prevent a lot of common issues.
Great points! I think using a premade enclosure might help with safety and organization. I'm careful about connections too; I have a digital torque wrench just for my setups!
Consider the eco-worthy 48V rack battery as a solid option. After factoring in all the costs of cables, a BMS, and the breakers for the 12V setup, you might find the 48V system to be more cost-effective and practical in the long run. Plus, saving space and having a simpler setup could be worth it.
I'd recommend going with the prismatic cells if you can. I had a frustrating experience with a 4S series using batteries from a brand that suggested it was fine, but I noticed they weren't balancing properly – one always ended up charging quicker than the rest. It might be worth it to pull the cells and manage your own setup rather than dealing with unpredictable balancing issues.
Yeah, I've read that balancing can be a real pain with multiple batteries, especially if they're different ages or models. Going DIY might allow you more control over that.
That's good to know! The 12V batteries I'm considering actually use EVE 280Ah prismatic cells, which are the same ones I'd probably get if I bought raw cells. I’ll definitely keep the enclosure and terminal specifications in mind.