Would it be ok to combine Lifepo and AGM just for emergency battery parallel? This would be a momentary switch and only used in emergency situation to start the engine.
Depends on how much of an emergency it is. There’s a really big chance you will damage your system.
Thank you for feedback. Very curious, in what way would it damage the system? We have 4 - 12v 200amp NG LIfepoe with a smart BMS, Cebo Gx, etc, and one AGM start battery power a little Yanmar 3 cylinder. If that helps.
Depends on the setup and the voltages but when you connect the 2 systems one is going to charge the other unless voltages are equal. Maybe the cable, fuse, batteries and BMS involved can take it, maybe not. Especially the lithium batteries can deliver a lot of power.
Check out Victron’s Cyrix-Li-ct 12/24-230.