Test: Alternator vs. no alternator = 10% MPG gain @ 70 km/h

[ecomodded]

Very nice gains. Its now a solar hybrid !

[vacationtime247]

Got this update in my email. Was thinking about doing this on my diesel tempo. Should only need the battery for keeping the ip on, brakes and lights. It's an odd set up. Serpentine belt runs from the crank pulley to the a/c to the p/s to the idler pulley back to the crank. Alternator has a seperate belt ran off the power steering. Take off the serpentine belt before work and put it back on for the ride home. Think the major draw from the battery would be the lights on the way home. Come to think of it, I'm gonna try it right now.
VT247

[vacationtime247]

Alright. That was quick. Took me longer to get it in the garage, find the right tools and test the volts on the battery than to disconnect the serpentine belt. Think I can take it off or put it on in less than 10 minutes. Just needed a 13 mm & 10 mm wrench. Disconnected the air intake heater too. Think it would draw to much off the battery. Think I'll try a 1 day off 1 day on as to not completely discharge the battery and kill it. Guess that will all be determined by the amount of voltage drop I get with my back and forth. It's 17 miles each way. Hopefully it will make the trip back and forth without me having to hook up the belt at work. But, just in case, I'm taking them with me along with a dvom.
VT247

[oil pan 4]

Originally Posted by steffen707

I thought if you had a deep cycle battery this wouldn't be a problem, because they are designed to be depleated and then recharged?

To a deep cycle battery 50% total discharge is considered depleated.

Originally Posted by steffen707

They seem to say that zero is 10.5volts, 30% left is 11.75, 80% is 12.42.

What that means is there is 0% useable power left at 10.5 volts.
If for some reason you were going to run the battery down to 0 then when you hit 10.5 volts you have used about half the total power inside the battery. But there is no reason to do this.

[steffen707]

Originally Posted by oil pan 4

To a deep cycle battery 50% total discharge is considered depleated.



What that means is there is 0% useable power left at 10.5 volts.
If for some reason you were going to run the battery down to 0 then when you hit 10.5 volts you have used about half the total power inside the battery. But there is no reason to do this.

Okay I thought the definition of depleated was zero power left.

[oil pan 4]

I have found that using LiFePO4 batteries in a vehicle you may want to charge limit your lithium battery bank.
The alternator belt on my truck is plenty tight and on cool mornings when I have to glow plug it and crank it for more than 3 seconds the lithium batteries draw so much power after start up they can make a tight v-belt slip squeak.

If you were to do an alternator disable and then try to charge these kinds of batteries by reenableing the alternator you might burn it out, since most car alternators are only ment to charge a battery used for starting and power the cars electrical system.

Or you could burn up the battery charging wire.
This happened this happened in my truck, after cranking and cranking then fireing it up on a real cold morning, it burned up its factory 12-14ga battery charging wire. To fix this I put a heavy duty alternator in and rewired the alt with an 8ga cable with soldered ends. Problem solved.

[oil pan 4]

Originally Posted by steffen707

Okay I thought the definition of depleated was zero power left.

Battery ratings are tricky like this. You have to know what you are looking for and know how to read between the lines.

[steffen707]

Originally Posted by vacationtime247

Alright. That was quick. Took me longer to get it in the garage, find the right tools and test the volts on the battery than to disconnect the serpentine belt. Think I can take it off or put it on in less than 10 minutes. Just needed a 13 mm & 10 mm wrench. Disconnected the air intake heater too. Think it would draw to much off the battery. Think I'll try a 1 day off 1 day on as to not completely discharge the battery and kill it. Guess that will all be determined by the amount of voltage drop I get with my back and forth. It's 17 miles each way. Hopefully it will make the trip back and forth without me having to hook up the belt at work. But, just in case, I'm taking them with me along with a dvom.
VT247

This mod was described to me as having a cancelling effect if you depleat the battery one day, then use the car's alternator to charge the battery back up the next. The alternator will probably have to work harder on day 2, then it would if you left it on during day 1 and day 2.

The only way this nets you a gain is if you charge from the grid where electricity is cheaper than vehicle generated electricity.

You should only charge from the car if you're in a situation where you don't have enough battery to get home, or if you're running the battery too low and might hurt it.

[steffen707]

Originally Posted by oil pan 4

it burned up its factory 12-14ga battery charging wire.

That sounds SUPER DUPER tiny for a battery charging wire. I'll have to measure my stock honda wire, but I know its way bigger than that.

[deathtrain]

Originally Posted by steffen707

This mod was described to me as having a cancelling effect if you depleat the battery one day, then use the car's alternator to charge the battery back up the next. The alternator will probably have to work harder on day 2, then it would if you left it on during day 1 and day 2.

The only way this nets you a gain is if you charge from the grid where electricity is cheaper than vehicle generated electricity.

You should only charge from the car if you're in a situation where you don't have enough battery to get home, or if you're running the battery too low and might hurt it.

correct.