Electric water pump, worth while?

[oil pan 4]

LiFePO4 do not do well in the cold. Been there done that.
I have gone from lead acid to LiFePO4 and back to lead acid, specifically AGM type.

[OliverSedlacek]

Went lithium battery 5-6 years ago and cranking is much improved over lead acid, even down to below 0 celsius. Had a lead acid leak on me and corrode a chassis tube, and the weight saving was a super low cost performance boost.

[oil pan 4]

AGM don't leak.
0c is nothing. That's about when I started noticing the cold numbing effect. When it gets down to more like 0f, aka real cold, they will struggle to put out amps and charging them when they are that cold damages them.

[Ecky]

One thing to consider is how you're powering your electric water pump. If it's alternator-produced electricity, that's an automatic -50% efficiency vs something mechanically driven. Certainly, mechanical water pumps waste energy by pumping more water than they need to, but I have my doubts that an electric one running on a conventional 12v system would be any better.

The only mainstream mass produced engine I'm aware of that uses an electric water pump is on Toyota's latest hybrid engine (e.g. 4th gen Prius). This is powered by the high voltage system, and producing the energy to run it is less wasteful.

[Blacktree]

A lot of BMWs have electric water pumps, as well. And ironically, it's a common failure point.