With a couple of days running the Li-Fe, I'm seeing a 10% improvement in economy. MPGuino was sitting on just under 6l/100km for the tank, now sitting at 5.5 (tank data reset with the battery disconnect).
I hooked up my battery charger to see how full the alt is keeping the battery.
With a Pb, it would take about 20mins to charge to full even if you connected the charger immediately after turning off the engine. That's about 2Ah on my charger. In normal use, I'd connect the charger about once a week, it took about 4hours to bring the battery up to float (~30Ah).
So I connected my Li-Fe to the charger, stood there as it settled into the appropriate charge mode, and it was done within 2 mins!
I think it's clear then why the alt has less work to do. Pb batteries need to be kept full for maximum life but unfortunately their charge efficiency drops to 50% as they reach that point - a lot of wasted energy. What's really disappointing is that OEM's still aren't offering this tech in any numbers, the real world fuel savings should justify the expense for at least the 'ECO' versions of ICE cars.
PS: I have this 12v Automotive LiFe charger:
https://no.co/g7200
Much easier than messing with hobby chargers
