Charging while driving - max performance

bob.hansen@yahoo.com

I built a "Mutant Vehicle" for burning man based on an EZGO cargo carrier. I have a load of LEDs on the vehicle for night time use - all powered by a Honda 2000 generator. I have been charging the cart batteries while driving which increases my range considerably (we drive, stop for 15 minutes, drive etc.) Works well but doesn't always keep up with the battery draw down if I'm driving more than stopping. Question: My charger puts out 20 amps at 36V - (720W). The LEDs don't pull a lot of power so I have lots of extra watts in the generator. Can I add a 2nd charger in parallel to take additional load off the batteries when I'm driving? I'm guessing the chargers are current and voltage limited so shouldn't cause a problem when car was not driving. Thanks much.

BGW

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JohnnieB

Two chargers in parallel is possible, but complicated.

The recommended max charge rate is in the 10% to 13% range of the Amp-Hour capacity at the 20hr rate. If you have a 36V battery pack made up from 225AH, the max charging amps will be in the 22.5A to 29.25A range.

However, while cruising a typical cart draws from about 50A to 75A, so the net charge rate WHILE DRIVING will be whatever the chargers put out less what the cart is using. If one of the chargers was rigged so it only fed amps to the battery pack while the motor was drawing amps, the max recommended charge rate shouldn't be exceeded.

Also, one or both of the chargers will have to be connected via a steering diode so there is no back-feed path through the chargers. (Unless the output voltage off both chargers are absolutely identical, the charger with the higher output voltage will back feed amps through the charger with lower output voltage, which may cause some smoke and fire.)

Basically, with a relay to turn the second charger on/off tied into the solenoid activation circuit and one or two 50A/100V diodes, you might be able get some more run time.

As for completely keeping up with the amp draw by the motor, your 2kW generator can't do it. With a stock controller, motor and 36V battery pack, my cart used about 2.8kW to travel 13 miles over mixed terrain and neither battery chargers nor battery charging is 100% efficient.

mattadata

Can you post some photos of this mutant?


Sent from my iPhone using Tapatalk

bob.hansen@yahoo.com

Great Information - thanks - a bit complex but the diode / relay concept sounds doable (a relay rated for >20amps for sure). Sorry - don't think I can post an image for 7 days since I just joined the forum.

bob.hansen@yahoo.com

More details on the mutant - it's carrying maybe 400lbs of stuff (large juke box, two amp/speakers, generator, two wwII drop tanks painted like rockets and a rolling stone lips and tongue front end) - and it will carry 12 people. It's rated for 3000lbs but all that weight does limit my range. You can see an old photo at the web site lotushocuspocus.com/rocketnroll

cgtech

Wait, arent you supposed to be using a giant pile of solar panels at burning man?

bob.hansen@yahoo.com

Well, that would be perfect, and some camps actually make that work but . . . the Mutant Vehicles are kinda power hungry. There's one car out there that goes through $40K worth of propane for their flame effect - and none of that is used to move the vehicle ;^)

Gregorio

Do it like Duck Flambe. Pick up a bunch of scantily clad women and use pedal power!

Seriously, what about another battery pack? Lithium is very light weight and it would be much less complicated that two chargers, no?

sformal

...or simply go to a petrol cart?

mutant

i would love to see that at "burning man".......does not petrol burn?...burning man?? seems logical:mrgree n: