AGM to Lithium Upgrade (12v)

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Eric M. asked Apr 19, '22

AGM to Lithium Upgrade (12v)

Has anyone moved from AGM to Lithium batteries? About to swap my 3x200ah AGM for 2x300ah LiFePO4 parallel, and want to be sure I'm understanding the upgrade and hear experiences...

I'm in a custom van, mostly charging with 700w solar + 100 | 50 Victron MPPT, a 30a Orion, and occasional grid charge from my 12 | 2000 MultiPlus. They're hooked to a VenusOS RPI (Cerbo) with a SmartShunt and temperature monitoring. All 3 charge devices have Lithium settings, and the batteries will have internal BMS. Am I missing another piece to this configuration - for lithium - like an external BMS or voltage disconnect?

Also, anyone who's done this upgrade, with the same AH capacity I know I can draw the batteries much lower, but has anyone experienced the differences in charging speeds? My AGM batteries spend most of their life in absorption, rarely accepting the full solar available even in bulk, unless I'm using my electric cooktop, which decimates my AGM's. Hoping this will change with Lithium.

Thanks for any advice or experience!

Lithium Battery

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2 |3000

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pwfarnell commented · Apr 20, 2022 at 08:24 AM

You need to know which model of batteries you will use and what the internal BMS does and the charging voltages before advice can be given on other aspects of the system.

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Answer 1 · 2022-04-20T00:47:43Z

Sarah answered · Apr 20, 2022 at 12:47 AM

Hi @Eric M. it looks like you have the makings of a good install. Provided you have reasonable quality batteries your config sounds good. Just make sure you double check the discharge rates for the batteries and the cooktop as many 'cost effective' internal BMS batteries have a relatiely low discharge rate. It will also be a good time to check that your fuses and cables are appropriate spec'd.

As far as the charging rates are concerned you will notice a big difference between Lithium and AGM - check the battery specs that you are purchasing for the exact charge rates - with your config you should see a full charge coming out of the solar panels given sufficient sunlight.

Sarah

2 |3000

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