still learning 32 cell 24v

[pyrochild:)]

im looking to get a 24v system, im starting with 16 cells shooting for 24v. ill add the next 16 when its time to make the jump to fully off grid. what i want to know, is there a down side to routing 2p8s? i plan on top balancing. but i am still new to all things solar. including diy battery. would it be better to just have 4 bms (8s) when the system is completed? additionally, if i have 4 bms. do i need to do anything to sync each bms to each other. or does the power just know what battery to go?

 

[Rednecktek]

Howdy neighbor! There are Pro's and Con's both ways:

2p8s Pro's -
Single BMS keeps all the cells in balance, cheaper to build (less BMS's), single battery footprint.

2p8s Con's -
Single point of failure, HEAVY!, larger footprint for two batteries.

Having separate complete batteries gives you an operational system if anything goes wrong, you just need to have multiple BMS's and multiple boxes. If your batteries are all connected up to bus bars with equal length wires there shouldn't be any real balancing issues. As for power, it'll be a pretty even spread where both batteries will absorb 1/2 the available charge naturally and if one were "deader" than the other, it will draw the lion's share of the current. I've seen this in my batteries for my camper where one tends to do more work than the other for some strange reason, but also takes more charge when the sun comes out. In the end both batteries will hit full about the same time so it all works out.

 

[Q-Dog]

Downside to pairing cells is you cannot monitor individual cells when you pair them together, if that matters to you.

For redundancy I would build 8s batteries and a BMS for each.

When you parallel batteries, physics determines how each battery charges. If you have 4 equal batteries they should balance on their own. Unequal batteries can work too, but it really depends on how unequal they are, and how hard you use them.

 

[pyrochild:)]

is there a place yall would recommend to find cells? the only site i have been recommended is sun fun kits but the eve lf304 is outta stock.

 

[Rednecktek]

Docan or batteryhookup

 

[pyrochild:)]

Docan or batteryhookup

That was so fast. I didnt expect a reply till tomorrow. But thanks! I found the ones I wanted!

 

[Rednecktek]

Some of us don't waste time with silly things like sleep.

 

[DIYrich]

is there a place yall would recommend to find cells? the only site i have been recommended is sun fun kits but the eve lf304 is outta stock.

LifePO4 Prismatic Cells

Discover our collection of high energy density LiFePO4 prismatic cells with long lifespan, high safety, and low cost of ownership. Ideal for electric vehicles, solar energy systems, and backup power systems.

www.18650batterystore.com

With that many cells, why not a 48v system?

 

[pyrochild:)]

LifePO4 Prismatic Cells

Discover our collection of high energy density LiFePO4 prismatic cells with long lifespan, high safety, and low cost of ownership. Ideal for electric vehicles, solar energy systems, and backup power systems.

www.18650batterystore.com

With that many cells, why not a 48v system?

well im starting with 8, then ill move to 16. then 32. but if i do it right 1 inverter for the whole system. rather then upgrade later.

 

[DIYrich]

well im starting with 8, then ill move to 16. then 32. but if i do it right 1 inverter for the whole system. rather then upgrade later.

Buy an 8-17 or 8-24 bms.

What multiple voltage inverter are you thinking of?