Battery venting

[drtbreau]

I’m trying to design my solar and electrical system. I’ve decided on starting with 2 lithium batteries. I’m thinking about building a cabinet behind the captains chair for my electrical. My question is do I need to account for any venting for the batteries? How far do they need to be away from an oven or other heat source?

[PNW_Steve]

Lithium batteries do not require venting.

I would recommend keeping an ABC rated fire extinguisher handy though.

[dzl_]

Originally Posted by drtbreau

My question is do I need to account for any venting for the batteries?

My understanding is venting (verb) would only occur in the case of catastrophic failure. LiFePO4 batteries do not need to be ventilation in the same way that a flooded lead acid battery does.

I’m trying to design my solar and electrical system. I’ve decided on starting with 2 lithium batteries. I’m thinking about building a cabinet behind the captains chair for my electrical.

Originally Posted by drtbreau

How far do they need to be away from an oven or other heat source?

You are unlikely to get a precise answer to this.

The general answer is that heat is one of--if not the--biggest factors harming LFP cycle life. The rule of thumb is LFP prefers roughly the same temperature range that you prefer (ideally in the ballpark of 50ish to 85ish, but 32 to somewhere around 105+/-10 would be acceptable).

The only one of these numbers that is a hard limit is 32*F, and even that is slightly malleable. The rest are general guidelines.

[dzl_]

I suggest this short article as a good introductory primer to how to take care of LFP batteries.


Here are some bottom line takeaways:

To sum up, for long and happy LFP battery life, in order of importance, you should be mindful of the following:

1. Keep the battery temperature under 45 Centigrade (under 30C if possible)
2. Keep charge and discharge currents under 0.5C (0.2C preferred)
3. Keep battery temperature above 0 Centigrade when discharging if possible
4. Do not cycle below 10% – 15% SOC unless you really need to
5. Do not float the battery at 100% SOC if possible
6. Do not charge to 100% SOC if you do not need it

[john61ct]

Overall best life span, cooler is always better than warmer

when not being cycled right down near freezing is best.

However while in use, discharging performance is best when warm, if high C-rates are needed.

And for charging, also if high C-rates are needed, then warmer the better.

If low rates like under 0.4C, then down into sweater weather, no problem.