Alternatives to the alternator

[Noel]

Car electronics want and expect around 13.8 vdc.... if you run for say, half hour with no alternator, your going to be dipping into 12.4~ range,,,, this is bad for the battery, and not good for electronics.

A transformer (DC-DC converter) could be used to bump up a deep cycle battery,... as you draw from it... up to a constant 13.8vdc

accomplishing this is possible with items many already have... a 4-600 watt inverter, and a 40amp battery charger.

Get to your location, and charge the deep cycle.

Originally Posted by CobraBall

Noel.

"DC-DC converter"

Convert DC what to DC what?

CB

[whitevette]

Originally Posted by dcb

Uhh... your diodes are CONSTANTLY cycled while the alternator is putting out juice. I don't think your friend thinking correctly if he doesn't think a couple horsepower wouldn't make a noticeable impact on mpg. Given that a beetle takes 12 hp to maintain 55mph, 2 hp is HUGE!!!

Yes, the diodes are constantly cycled...back & forth between battery voltage and alternator voltage(regulated). But slammed between zero and 14+?
I think he used 2 HP as an illustration... to make a point. I know it doesn't take much at all to give my ScanGauge the jitters. Now I'm skeered! I think I'll pass....

[dcb]

Sorry you got skeered. Lots of good ideas get killed by would be know-it-alls everyday.

[modmonster]

i think its a great idea. car electrics should be able to take switching on and off because thats what happens when you turn on and off you car!

the only bad thing might be if you lose the radio code when tinkering.

[modmonster]

i know lots about batteries - i have custom built electric bikes.

for this application it is easiest to get cheap deep cycle batteries. however it would be best long term to go for nicd or nimh batterys.

it might be good to leave the normal battery untotched and have a relay system that disconnects alternator and switches to auxillery battery with one button press. then if you mess up you can always switch back to the normal battery.

[orange4boy]

[QUOTE=CobraBall;54588]Magnetos are great if you are operating a race car, but not very reliable in a street vehicle. Besides to stop the darn engine you must have a grounded kill switch to stop the thang from running. You turn off the key and it will still run. Really, really, safe......not!




They are used universally in light aircraft engines although they usually have two in case of failure.

[CobraBall]

Originally Posted by orange4boy

They are used universally in light aircraft engines although they usually have two in case of failure.

True and..

"...the vast majority of aircraft with piston engines are using magnetos as their sole ignition source. In spite of over 100 years of experience with magnetos, extensive certifications of aircraft magnetos and quality control requirements by the federal authorities, they still fail or require maintenance, more often than any other part of an aircraft engine. Slick Service Bulletin 2-80 states that 4200 and 6200 series magnetos now being produced should be inspected externally every 100 hrs. and internally every 500 hrs. Parts subject to wear should be replaced as necessary at this time, magneto shaft bearings must be replaced every 1000 hrs." SOURCE: Electronic Ignition for Aircraft