The thing I really like about the iota chargers is you can feed them anything from 90 volts to 180 volts, AC or DC and they put out a rock steady 13.4 or 14.4 volts DC. I didn't believe it at first but someone who dug in to the unit tried and now uses it on his electric truck to charge a 12v battery from his traction pack for all the old existing 12v items.
I bet a 35 amp switching Vector charger will operate over such a wide range of input voltage as well and they sell for about $65 - I have a bunch of them. My point is that with a $3.00 transistor and a decent core with a bunch of turns of wire and a few bucks of components you could build a switcher to drop any DC battery voltage down to 14 volts at a pretty decent current. That iota charge controller doesn't list any current levels but it looks like it should work pretty well in bulk mode while you are driving.
Nice thing about an electric water pump is that you can continue to get heat from the heater with the engine off like when stopped at a light with engine off and regulate the pump speed (wasted energy) increasing it when it is needed like when you are burning a lot of gas and not a function of engine RPM so that lugging it on a hot day you could run the water pump faster for more cooling etc.
I had know it was bad since I bought the car a few months ago , and as its getting colder (and batteries dont like cold) the big block 1 litre engine has been getting slower and slower to crank up and fire.
The battery's capacity is suitable for engines over 2 times that size , so for it to be struggling to turn the small engine I knew it was dead.
I have been noticing the car was a little down on power as well compared to when I bought it.
Amazingly when I repalced the battery engine power is back to normal again.
Ime supposing that the dead battery was always under volatage and wanting a full charge and that the power loss was from a full loaded alternator.
Unfortunately it will probably show up in this tank full FE test. , but interesting anyway the effect of the alternator on power and FE.
Oh, one thing I use a lot is a Deltran water proof battery tender. It charges at a lowly 800 mA up to 14.6v and then drops back to 13.2v float. I would strongly recommend one of these (or a larger version) if your messing with a disconnected alt. The battery will die a quick death cycling it without a good true full charge. I use this charger on our van, I suspect the alternator is a bit off in the van and never full charges the battery.
On the wagon the Deltran will show a full charge in 30 minutes and the van takes 4-6 hours.
Even running the alternator as normal the cars starts much quicker in winter and I figure it doesn't have to run the alternator as hard to get the battery charged back up after sitting a while since it starts ?full?.
Even a solar charger would likely work in most cases for this "topping off" of the battery
Definately Brock - most electrical systems if not run for hours will not charge the battery as much as it needs. A new battery should be charged at a slow rate for about a week before it really gets the self discharge down to under 0.1 amps. Deltran makes some really great chargers . . . just wished they made a really high output current version.