Kyleservicetechs 80 Amp Supply Updated
 

A previous thread shows my Auto alternator setup powered by a 3.5 Hp Briggs engine. The output of that alternator was limited by the engine. Anything over 40 amps, and the Briggs engine stalled out.

Last weekend, Harbor Freight had their 212 cc gas engine on sale for $99.00. Picked one up, along with a $19.99 extended two year warranty. Warranty indicates if anything goes wrong with this engine, they give you a brand new out of box engine.

After a few days of work, the attached photos show the results. The unit gained 13 pounds of weight over the Briggs engine due to the heavier Harbor Freight engine. Total weight is 56 pounds, still less than one 120 ampere hour deep cycle battery.

The little box has Anderson Power Pole connectors wired all in parallel for connection to the battery, alternator, and one or two chargers. The box also contains a microcontroller that delays powering up the alternator for 30 seconds while starting the engine. The microcontroller also keeps count of the number of charge cycles, and kills the engine after 20 minutes.

Now, we need to wait for a good day at the field to try it out!

03-13-2012 Update Field Trials!
Take a look at the new photos at the field. The control box was moved to a much lower vibration location. This setup puts out 52 Amps with absolutely no problems. The Cellpro Powerlab 8 charger is programmed for 28 Amps charge rate to the 6S4P A123 battery pack. Recharge time is about 16 minutes or so.
The extra black box on top of the black case is my home built high current A123 balancing system for the "other"parallel battery pack. This balancer also displays the individual cell voltage on all six series cells.

Looks nice, The only thing missing is a belt guard, to save the finngers. Think Safety!

Yup, got the sheet metal, just need to bend it up to make a belt guard.

Whats that cap for under the handle......Oh thats where the GAS goes!!!!!!!!
I guess if we take it out of the plane it still has to go somewhere. Anyone hookup a Solar Charger or Inverter System that will charge the bigger batteries.
Harbor freight also has some small cheap gensets if you don't want to build your own. I've seen these ready to go on sale for $100.

Yeah, I've gone the route of two 120 Ampere Hour deep cycle batteries in parallel for charging them 24 A123 cells in my Big Stick. Problem is the Cellpro Powerlab 8 charger is pulling 54 Amps out of the 12 Volt battery setup. That's way beyond what those deep cycle batteries are rated for, and I've found that it really kills those lead acid batteries. I got less than a year service out of two in parallel before they were crap.

As for the gensets, you can't use their 12 volt DC output, its not pure DC. So that requires a 120 VAC to 12 VDC power supply that for me, puts out 60 Amps. One of those will cost over $300, plus the $100 for the genset.

A real concern is these gensets often use an inverter inside them to provide the 120 VAC. Don't know if those inverters can handle the very high peak currents pulled by these AC/DC power supplies during their normal operation.