Over-charging the battery to ease alternator load

[Cobb]

At one time I use to precharge my starter battery in my Honda. It lasted like 7 miles or so. I swear some company makde 14 volt batteries, alternators and chargers for racing applications if not audio competation, but I can not find them.

Yeah, rig up a switch to the bottom of your gas petal so when you floor it your head lights dim. No, seriously, a full load on an alt is like 3 hp taken from your engine. Rig it so it only works when you push a switch like when engine braking or the voltage falls below 12.4 volts or something. Thats what Honda does and has been doing sofor years by way of their ELD.

[brucepick]

Most of the MPG lost in a alternator is from
1) Providing current to run the car: Computer, fuel pump, headlights, more
- - - These are easily seen when watching voltage drop on a car running only on a deep cycle battery without alternator. Voltage drops as each item is added.

2) Waste heat loss due to keeping the battery at approx 14.x volts steadily.

3) Drive belt friction and alternator rotating bearing drag

[brucepick]

Originally Posted by Cobb

... I swear some company made 14 volt batteries, alternators and chargers for racing applications if not audio competition, but I can not find them...

I found them. It's the XSP-D1400; you can google for it. It's an AGM battery. About $260 plus shipping. The charger is $200. Charger link. I searched long and hard, could not find another 14V battery or charger available, or a significantly better price either.

With the battery plus charger plus shipping totaling about $500, I decided that was too much money for a lead-acid chemistry battery, at least for my money.

[topcat]

Thanks for the great ideas here. I was looking for something simple and not too invasive. I like the idea of the alternator kill switch, only turning it on during braking or when volts drop too far. But I could not see any "prior art" for my Toyota 1ZZ-FE engine.

I think I will go with the fly-lead connection to the battery, next to my block heater connector. I will try the CTEK charger in "frost" mode where it charges up to 14.7V to try to get a bit more "juice" into the battery. This seems to be least invasive, and least extra weight to carry around.