FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Could you provide a link to the Batteries?
anyone wanna help me convert my 12v diagram to 24?
- Thread starter starchy
- Start date
pretty much these:
bigbattery.com
12V OWL - LiFePO4 -170Ah - 2.17kWh - BigBattery.com
The BigBattery 12V 2.17kWh LiFePO4 OWL is cost-effective and the perfect lithium rv battery for vans and RVs, with new LFP cells for the safest lithium chemistry available today.
bigbattery.com
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
OOPS.... Houston, we have a problem.
I found this in the spec:
You can't build a 24V system out of these batteries because they can not be put in series!
I found this in the spec:
You can't build a 24V system out of these batteries because they can not be put in series!
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
It is most likely a restriction of the BMS. When a BMS shuts off, the voltage of the total system appears across the FETs of the BMS. In order for a 12V BMS to handle 24V, the FETs have to be designed for 24V and that adds cost.
Have you already purchased the batteries?
i'll be waiting until monday for a response from BigBattery but according to a .pdf they sent me a while back i can run what i have in series:
"This battery can be connected in parallel up to eight times and can be connected
in series twice (for 24V), as long as the total amount of these batteries in your
configuration never exceeds eight total batteries."
still not sure how to go about doing so with these anderson connectors.
"This battery can be connected in parallel up to eight times and can be connected
in series twice (for 24V), as long as the total amount of these batteries in your
configuration never exceeds eight total batteries."
still not sure how to go about doing so with these anderson connectors.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Don't you love the clarity, precision, and consistency of documentation from tech companies? 
Either way, you are probably going to have to make up some custom cabling with Anderson Plugs.
Are there one or two Anderson plugs on the batteries? I can't tell from the pics.
Either way, you are probably going to have to make up some custom cabling with Anderson Plugs.
got contradictory responses from them yesterday. most recent was they no longer recommend series connections and you void the warranty in so doing. maybe i should just adapt this diagram to a 12v system. i guess the main reason i was gonna go 24 is this whole "series is better for the long term health of the batteries" notion.
John Frum
Tell me your problems
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Who said that?
ok, well if i'm going back down to 12 i guess it'll look something like this. i guess i need to size down the fuses. i'm a little confused about the formula for that. also, can i size down the wire to the batteries? these anderson connectors are pricey and i'm not even sure these batteries accomodate 4/0. also, according to prowse the wire to the inverter should be 4/0. (image from his book)
