Planning of a DIY LiFePO4 battery - air conditioned
Hi,
since a couple of weeks, I'm thinking and planning about building my own LiFePO4 battery to replace my two "old" lead acid 100AH AGM group 24 batteries (installed below the stairs) for my 2020 Entegra Odyssey 26D.
I would like to stay below $1,000 for the whole project and try to design the battery in a way that it would automatically heat and cool itself, depending of the ambient temperature to maximize life time and prevent damage. I don't want to move the battery to the inside of the coach because of space reasons, so it must fit in existing battery space. Later I think about adding solar, but first the new battery has to be build.
So far I've a battery design with the following components in my head:
- 4x EVE 280k, 3.2V, 280AH grade A cells (from an US distributor - about $540)
- JBD BMS 4S 12V 200A (about $125)
- TEC1-12706 peltier cooler/heater with two headsinks and two fans, max. 70 watts (about $25)
- 2x digital temperature controller XH-W3001 (about $10)
- 2x SPDT and 1x DPDT relay to control the peltier/fans with the temperature controllers
- Renogy 500A shunt mounted on the battery (display mounted inside the rig) - (I already have that - costs about $75)
- 300A circuit breaker (about $20)
- CellMeter8 battery cell monitor ($14)
Some additional design considerations:
- Everything should be mounted in/at a wooden box made from 1/4" thick plywood (<=7.5" width, <=14.5" heigth, <=22" length).
- the peltier heatsink located inside of the battery needs a small funnel underneath with a pipe to get rid of the condensate water if cooled
- the DPDT relay is required to change the polarity of the peltier to choose between cooling and heating
- the two SPDT relays are required in XOR to only active the peltier if either of the heat or cool thermostat is active, but NOT if both are active by mistake!
- the conditioned airflow of the pletier (directed via a plexiglass sheet) runs over, under and one end of the battery (too less space on the side of the cells)
Here is the planned schema:
The battery should look like this:
I would be interested in your opinions and suggestions for improvements!
Thanks in advance,
Frank
since a couple of weeks, I'm thinking and planning about building my own LiFePO4 battery to replace my two "old" lead acid 100AH AGM group 24 batteries (installed below the stairs) for my 2020 Entegra Odyssey 26D.
I would like to stay below $1,000 for the whole project and try to design the battery in a way that it would automatically heat and cool itself, depending of the ambient temperature to maximize life time and prevent damage. I don't want to move the battery to the inside of the coach because of space reasons, so it must fit in existing battery space. Later I think about adding solar, but first the new battery has to be build.
So far I've a battery design with the following components in my head:
- 4x EVE 280k, 3.2V, 280AH grade A cells (from an US distributor - about $540)
- JBD BMS 4S 12V 200A (about $125)
- TEC1-12706 peltier cooler/heater with two headsinks and two fans, max. 70 watts (about $25)
- 2x digital temperature controller XH-W3001 (about $10)
- 2x SPDT and 1x DPDT relay to control the peltier/fans with the temperature controllers
- Renogy 500A shunt mounted on the battery (display mounted inside the rig) - (I already have that - costs about $75)
- 300A circuit breaker (about $20)
- CellMeter8 battery cell monitor ($14)
Some additional design considerations:
- Everything should be mounted in/at a wooden box made from 1/4" thick plywood (<=7.5" width, <=14.5" heigth, <=22" length).
- the peltier heatsink located inside of the battery needs a small funnel underneath with a pipe to get rid of the condensate water if cooled
- the DPDT relay is required to change the polarity of the peltier to choose between cooling and heating
- the two SPDT relays are required in XOR to only active the peltier if either of the heat or cool thermostat is active, but NOT if both are active by mistake!
- the conditioned airflow of the pletier (directed via a plexiglass sheet) runs over, under and one end of the battery (too less space on the side of the cells)
Here is the planned schema:
The battery should look like this:
I would be interested in your opinions and suggestions for improvements!
Thanks in advance,
Frank
