Hello, I'm trying to find out if it's ok to charge a FLA engine starting battery with a lithium battery charger.

My RV uses a 12v lithium-iron battery, and has a charger with a lithium profile. This charger has a secondary 4A output for charging the engine battery. But I've discovered this 4A output uses the same profile as the main charger, which is set to lithium. Is it ok to connect this 4A output to my engine battery? I would use it to keep my engine battery topped off while parked for extended periods in my driveway or while camping.

The lithium battery system resting voltage is around 13.6. That should be perfectly fine for a FLA battery, right? It does go up to 14.4 for a short time, I think that should fine, too? Remember it's on a 4A limited output, so I don't think it would necessarily bring the FLA battery up to 14.4.

The manual says:

Two DC outputs for charging two batteries
The main DC terminal can supply the full output current. The second output, intended for charging a starter battery, is limited to 4 A and has a slightly lower output voltage (12 V and 24 V models only).

 

I found this comparison.

 

That should be perfectly fine for a FLA battery, right? It does go up to 14.4 for a short time, I think that should fine, too? Remember it's on a 4A limited output, so I don't think it would necessarily bring the FLA battery up to 14.4.

I don't see how you could think a charger for a different battery chemistry would be okay for lead acid. If I wanted a maintainer for lead acid batteries, I'd buy one. I have 4...

The maintainers I have use an equalizing voltage of 15.7V.
https://batteryuniversity.com/article/bu-404-what-is-equalizing-charge