Lithium with lead in a house bank -Is this a valid strategy and worth your time?

[alaskanviking]

I stumbled on these videos tonight, essentially combining lead acid and lithium into the house bank. He makes some interesting points, and has peaked my curiosity.

Specifically the advantage of having the lead in the system to protect the alternator if the lithium BMS takes it off line, makes sense.

I don't agree nessesarily that the lithium can't supply a large high amp load without damaging itself. However I believe there is an advantage of using a lead starter battery for a starter or windless ect. Over lithium I don't know.

I also don't like his setup, in the first video with mostly lead acid and just enough lithium to get through the night. I simply do not have the space for decent capacity using lead acid. The same space yields 1000+ah in lithium. My goals are similar, bank sized to last 3-5 days roughly.

In my 24v system, I'm thinking this would equate to 4 gc2 6v lead acids and roughly 700-800ah of lithium in the space available.

Is what he says in the video a viable strategy? Is it worth the space premium to use some lead, which means you cant have as big of a lithium bank in the same space?

If so... What would be recommended setup or best practices? I get the feeling there may be something here worth taking a deep dive into. The second video is probably the most relevant to most of us.

Can you connect to a starter bank with an ACR, which in theory lets you do this and prevents draining your starter batteries? Can you use a zero loss battery isolator like a victron Argo to charge the different parts of the system?

Can you use a separate ac charger to charge the different parts of the bank, ie contact a charger only to the lead acid batterys?


https://youtu.be/tAuPfgZgXec
Big lead bank with lithium

https://youtu.be/sqT27KbxRec
Big lithium bank with lead

[smac999]

the one I set up recently had a single group 31 lead acid with a few lithium. with them on a 1-2-all swtich. while motoring switch on both and house bank is both banks so if internal BMS opens the lead will keep going and save the alt. at the dock the switch goes to lead only. chargers and loads on lead only so the lead floats at dock and not lithuim. it's also a small backup for when the lithuim fails. every lithium bank I've seen has failed or had a problem at some point. including namebrand mastervolt and victron ones etc. I would never run a lithium house bank without a backup. and i would always have separate lead battery for engine starting as well. so always 3 banks.

internal BMS batteries can not give high loads to start engines, run bowthrusters etc.

previous setup had a lithium house, lead start, lead bow thruster. external bms so not worried about alt. but the house panel feed had a 1-2 (no all) swtich between lithium house and bow thruster bank for backup house power if the lithium failed

[ahun]

My concerns exactly. I need to run the anchor windlass from the house bank. My lead crystal batteries died and I am thinking of lithium, but they have really low discharge rates. This might be the solution? Hopefully others will chime in with opposing opinion to highlight possible downfalls.

[alaskanviking]

I like the idea of using 1-2-all switches between banks, however I think there is a danger issue that's possible if the lead acid isn't charged and you connect them at the switch. It would surge electricity into the lead acid at a faster rate than they can accept.

Maybe a second switch with a resistor or something. If it's just you controlling Its probably not an issue. I think this is a good idea regardless, but I need to think on it a bit for the best way to wire it up