Solar size compared to battery bank size?

[reubenray]

Will the solar panel size decide what size or how many batteries will work? I have a 370 watt solar panel with a single AGM Group 24 battery. Also aren't LifePO4 batteries susceptible to being damaged in freezing temperatures?

[Country Campers]

reubenray

I have moved your post out to its own thread. This will help this discussion and the other stay on track.

Brian

[ncitro]

Will the solar panel size decide what size or how many batteries will work? I have a 370 watt solar panel with a single AGM Group 24 battery. Also aren't LifePO4 batteries susceptible to being damaged in freezing temperatures?

Most modern LiFePO4 batteries designed for RV use have a BMS that limits charging below freezing to protect the cells, and use below 0F (I think, I do not camp that cold). Verify with the specific battery you are considering.

The solar panel size determines how fast your batteries will charge. They are basically a sun powered battery charger. More batteries does not affect that, other than you have more to deplete that would need to be charged. You size the whole system (number of batteries and amount of solar) based on your usage.

[TucsonJim]

Neil gave some great info. I'm using four Li Time 230 amp hour batteries. Here are the temperature specifications for my specific batteries:

Charging: 32°F to 122°F (0C to 50C)
Discharging: -4°F to 140°F (-20C to 60C)
Storage: 14°F to 122°F (-10C to 50C)

I do have a Battery Management System that shuts off charging at 32°F. But I also have a thermometer near the batteries that I monitor if the temps start plummeting. You can use them with no issues during cold weather as long as the temp doesn't drop below -4°F. But lead acid (including AGM) batteries have their own peculiarities at low temperature, especially if they are approaching full discharge.

If you have a 370 watt panel, you can expect to get approximately 220-240 watts on a sunny day in the Southern USA during winter months. And you should yield in excess of 300 watts on a summer day.
220 watts on a winter day will provide enough power to fully recharge an AGM battery. 300+ watts should allow you to recharge two depleted AGM batteries in the summer.

On my system, my 2000 watts of panels provided a maximum of 1200 watts last week in Southern Arizona on a cool winter day.

Jim