Batteries in the cabin

[nicklee]

Thank you. I'll pay attention to the battery temperature.

 

[ean_p]

Are you UK based?
I can't see it being a problem if you battery box benefits from cooling from the hull. My battery box is under the saloon seat on the starboard side. We have our old lead bank and the new lithium battery adjacent, in seperate boxes. The lead bank( 4xTrojan T105RE) are on permanent float by vertue of a Victron orion. Ditto the generator battery. They sit at a constant 30degC. The lithium battery is being charged by solar, up to 28A at 24v and being discharged at upto 1800w when running the watermaker, immersion heater or induction hob. The ambient air temperature today is 30degC and the water temperature is the same. Current lithium battery temperature is 31degC just after midday. It will drop to about 30degC over night if I leave the little computer fan running. The BMS does get hotter. It goes up to circa 40degC when we are cooking or making water. If you use drop in batteries with the BMS in the battery case, then the heat from the BMS will heat the battery cells. This may hold the battery temperature up more than a DIY battery where the BMS is in a larger box and there is an opportunity for heat to be lost to the surroundings.
When I was using my Trojans as the main house bank, in this hot environment, they would often hit 35degC under normal solar charging unless I left the battery box lid off. They would still hit 33degC. The low resistance of lithium really helps

The fitment is in our camper van as a 'trial' exercise. As such it'll still be fitted into what is effectively a locker under a bench seat. Unfortunately it won't be relieved with the presence of a 'cool' hull skin close by!
In the UK and North EU they'll be no issues but as the van is certain to venture into the south of the EU and quite likely Morocco, then the chance of ambient shade temps in the middle 30's and into the 40's is almost a given. Ventilation if it becomes necessary will be a floor vent with a fan or fans pushing the locker air out of the side wall . Intuition tells me its better to push the air outside then to push the air inside.....!

 

[geem]

The fitment is in our camper van as a 'trial' exercise. As such it'll still be fitted into what is effectively a locker under a bench seat. Unfortunately it won't be relieved with the presence of a 'cool' hull skin close by!
In the UK and North EU they'll be no issues but as the van is certain to venture into the south of the EU and quite likely Morocco, then the chance of ambient shade temps in the middle 30's and into the 40's is almost a given. Ventilation if it becomes necessary will be a floor vent with a fan or fans pushing the locker air out of the side wall . Intuition tells me its better to push the air outside then to push the air inside.....!

Which way to push/pull the ventilation air will depend on day or nighttime. Often its cooler at night, obviously hotter during the day.
We are in pretty constant hot conditions 24/7 here in the Caribbean summer. I run 4 computer fans cooling my Victron MPPTS and B2Bs as well as my batteries. Mr Google suggests 35degC in the Moroccan interior during the day and circa 22degC at night. Fairly typical Med sort of summer weather.
Taking advantage of night time cooling might be something you want to consider.
If you leave the van parked up during the day with windows closed, it's likely to get way beyond the outside air temperature.
It's not so easy keeping the lithium at a reasonable temperature in a van in hot weather.