Combining Lead Acid and Lifpo4 batteries

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Oil Gypsy

Veteran Member
Sep 25, 2019
Vessel Name
Vessel Make
Grand Banks 36 Classic #248
I’m just installing a new power inverter and 4 lithium batteries, my existing system consists of 4 lead acid batteries. I would like to keep the lead acid batteries as they are relatively new and use them for engine starting and as a back up for the lithium batteries. I am going to use the lithium batteries to power the inverter/AC loads.

I have a twin engine set up and would like the both sets of batteries to be charged from the engines, I am also going to fit 400w of solar charging, primarily to keep the lithium batteries charged.

To me electricity is akin to magic, designing my own circuits is a quick road to disaster, fried components and smokey cables. Ive spent hours looking for diagrams for similar systems on the internet with no success. As a last gasp I would like to know if anyone else has a similar set up or knows of the whereabouts a wiring diagram that would meet my situation.

Given the knowledge level you describe, I think you need to get professional assistance. Any example drawings will be specific to a particular boat and its particular electrical system. Figuring out what parts are applicable and which are not, and adapting all that to the specifics of your boat and your usage is the help you need, and it requires an in-depth look at your existing electrical system.

I see you are in Canada, but not sure where. Jeff Cote at Pacific Yacht System seems to have a good reputation at least for his videos and lectures. Presumably his actual work is as good, so he's one option. Others may be able to provide additional suggestions.
A good place to start is the YouTube vids at Emily & Clark’s Adventures. Clark has been doing this for sometime and has developed some hardware to let LiFe & FLA work together.
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