Mixing AGM and LiFePo4

[DW SD]

My home alarm battery is 12V and 7Ah AGM. I realize they float this battery for its entire life, unless your power goes out.
Each lasted 6 or 7 years. I think my AGMs in the camper will have a similar experience!
Actually, I've bought 4 more LFP cells and will likely remove 550lbs of lead acid AGMs to save weight and offer some storage space.

I still feel the hybrid is a good one, especially if on a budget. Or you have good AGMs you don't want to waste.

 

[Luthj]

On Marine applications where voltage spikes from a BMS disconnect can damage life sustaining (or just old) equipment, it isn't unusual to see a small lead battery in parallel with the pack, but on the load side of the main disconnect. This battery would never supply any current under normal circumstances, and is just to absorb and transients during a disconnect situation.

 

[Mike H]

On Marine applications where voltage spikes from a BMS disconnect can damage life sustaining (or just old) equipment, it isn't unusual to see a small lead battery in parallel with the pack, but on the load side of the main disconnect. This battery would never supply any current under normal circumstances, and is just to absorb and transients during a disconnect situation.

How would you wire in a lead acid battery in parallel?
Connect the lead acid battery to post 2 on selector switch and lifepo4 battery to 1 on selector switch and then set it to all ?

 

[DW SD]

How would you wire in a lead acid battery in parallel?
Connect the lead acid battery to post 2 on selector switch and lifepo4 battery to 1 on selector switch and then set it to all ?

Yes.
Or with busbars. Or connect @ the posts directly.
I like the idea of switch(es) to isolate.
Lots of ways to do it.
Doug

 

[Mike H]

Yes.
Or with busbars. Or connect @ the posts directly.
I like the idea of switch(es) to isolate.
Lots of ways to do it.
Doug

Great thank you.
I am waiting for my batteries to arrive. Then my project will start. I am trying to keep my SLA battery for my boat motor and lifepo4 for my house bank. Still looking into how to wire it all up.
I am going to use ElectroDacos SBMSO for my bms

 

[Ranchero7]

When you guys combine systems like this do you use two battery monitors? Or is that not feasible/accurate given both sources would be read in available ah calculations?
Thanks!

 

[grizzzman]

Yes on the FLA I run a simple Volts-Amps meter, with that said I do have a system similar to this one. I will install it on the FLA bank. It is capable of controlling a contactor. There will also be a manual override switch on the contactor as a backup control mode.