Swapping Sealed Lead-Acid for LiFePo4

[Nigel s]

We currently have a system that uses 4* 250w panels, 2s to P into a Victron 100 | 50 CC, 2000w inverter. Our use is (well) below average; we have LED lights, Internet and fridge, charge phones etc., a washing machine, minimal use of tools (I have a 3500w generator for drills and stuff). The batteries are 2* 12v 250Ah in series that have reached the end of life. About an hour after charging has stopped they are dropping from 25 to 23 (even lower if I forget to look), at which point I turn off the inverter until morning; they reach a float of only 26.6 now. They are five years old, have done about 500 cycles, but for the last year we have probably over-used them because we had a separate small system to run the freezer and THAT battery cracked (no idea why; I decided to put the freezer on 2* 270w panels with a 1000w inverter so we could use the spare capacity as a redundancy feature for Internet/lights at least in the event of a home bank fault) so we had to add the freezer to our ‘home bank’. We’ve now had a little influx of money and I’ve bought an AGM 120Ah battery for the freezer (it lives outside in an insulated cabinet but can still get cold) and it’s all good. I’ve also decided to buy 2* 12v 280Ah LiFePo4 batteries to do a swap-out with the almost dead ones. The Victron has a setting for LiFePo4 which I will apply, and before I swap them, I’ll check SoC and charge them with a generator/charger.

…my question is; This will be the second time I’ve replaced the batteries, the first time from simple LA to what we have now…is there anything that I don’t know that I should before I do the new swap and change the Victron to the LiFePo4 setting?

[Bala]

Just few things to be aware of. Assuming they are an off the shelf batertwith built in bms.

Make sure the manufacturer states they can be run in parallel.

Make sure the settings in the charge controller match manufacturers specs.

There should be a voltage cut out for the batteries. If they do cut out on low voltage you need to know how to get tgem going again. Its common to need a non smart charger.

i have 2 12v lithium systems in vehicles. I run a low v disconnect set to above the battery bms disconnect so if I do run low I can just start charge and all is well.