Thread: LiFePO4 or Lead Crystal to replace AGM?

Good suggestion Drivesafe, I'll try that thanks.

Hi, I made the leap to LiFePo4 in my van about a year ago, I did a major upgrade to the complete system. My very strong advice is that it has to be regarded as a system change, not a battery change, and along with it a paradigm change in how you utilise your electrical energy storage. LiFeP04 is just fantastic, it's ability to supply high current draw and maintain 13V while doing it for extended periods of time is the first in a long list of advantages over Sealed Lead Acid (SLA), and the paradigm change is that you have to use them differently, they are not SLA, do not use them like you use SLA. So here is the trap, there is a lot of poor information out there so do your research and make up your own mind, it is your money, and usually quite a lot of it.

Peter

Hi Peter, thanks. Could you maybe expand a little on what you have said. Did you have the system fitted professionally or did you fit it yourself? Does your van have combination charger/inverter devices? Do you charge the batteries with the tug while driving? How much solar do you have & what size LiFePo4 pack did you fit?

Originally Posted by Milton477

Hi Peter, thanks. Could you maybe expand a little on what you have said. Did you have the system fitted professionally or did you fit it yourself? Does your van have combination charger/inverter devices? Do you charge the batteries with the tug while driving? How much solar do you have & what size LiFePo4 pack did you fit?

I fitted the whole system myself, 300Ah LiFeP04 battery (with BMS), Victron Energy Multiplus 3000w inverter/charger [fully programmable with dedicated voltage sensing, I can not understate how important dedicated voltage sense is] Victron Energy 100/50 solar controller, [again fully programmable] 840w solar panels [simply] and VE battery monitor, most importantly a programmable low voltage cut off protection for the battery from Intervolt. You must not rely on the battery management system cut off to provide a low voltage safety cut off point for the system, it's only there as a OMG panic stations savior.

I can be using the microwave or coffee machine (a George job) the inverter is pulling 120 to 130A, turn on the van water pump, TV, lights whatever and not so much as a micro hiccup. I do not charge from the D4, absolutely no need.

Peter

Hi Peter and the total cost was?

Originally Posted by PeterJ

I fitted the whole system myself, 300Ah LiFeP04 battery (with BMS), Victron Energy Multiplus 3000w inverter/charger [fully programmable with dedicated voltage sensing, I can not understate how important dedicated voltage sense is] Victron Energy 100/50 solar controller, [again fully programmable] 840w solar panels [simply] and VE battery monitor, most importantly a programmable low voltage cut off protection for the battery from Intervolt. You must not rely on the battery management system cut off to provide a low voltage safety cut off point for the system, it's only there as a OMG panic stations savior.

I can be using the microwave or coffee machine (a George job) the inverter is pulling 120 to 130A, turn on the van water pump, TV, lights whatever and not so much as a micro hiccup. I do not charge from the D4, absolutely no need.

Peter

Thanks Peter, well done building it yourself. Some food for thought there. I take it you bought the battery complete with BMS rather than assembling the battery + BMS yourself. I am considering building from scratch.

Yes the issue of cost is always the biggie, but I have some specific requirements that I wanted to accommodate and simply did not want to do the generator thing, the answer is approx $10k, remembering that a lot of that is on equipment that anyone could spec into a FLA system or for that matter Lead Crystal. I have no exposure to Lead Crystal at all so can not comment about them.

I was going to build my own battery initially, CALB cells, build my own mounting box (compression plate) and use a commercial BMS but I became aware of a "sale" that included exactly what I wanted and when I did the numbers there was not a real lot in it. There was also a bit of a time issue for me at that point and the process of top balancing the individual cells, assembly and then running base line capacity checks was going to take a while.

I did a base line check on my battery and without boring you to tears I charged it to 14.02 (no load, about 13.7 loaded) and set my cut off at 11.8V (loaded). I hooked up a 750W bar heater to the inverter and turned it on. 4 hours and 43 minutes later it hit the low voltage cut. The Victron Energy battery monitor indicated 288Ah from a nominal 300Ah capacity and when you factor in the inverter efficiency I was very happy with the result. I run much more conservative cut out ordinarily but there you go.

Thanks Peter. Does the Victron Energy 100/50 solar controller charge the batteries direct or through the Multiplus?