Bubblehead

Are there any ROAR approved chargers? I was told tonight that my charger is NOT legal, because my batteries off the charger was 8.5V. I'm new to LIPO's and all I did was set my charger to LIPO and start charging the LCD displayed 8.4V.

Andy Koback

iTrader: (280)

I don't know what the ROAR rules are regarding this issue but in the BRL League, (Oval) batteries can't read more than 8.44 volts for 2 cell and 4.22 volts for 1 cell at race check-in. Check with your local track directer and see what he says.

Bubblehead

Andy, If you went to tech and your batteries were 8.46V, what would you do to get your batteries to 8.44V?

CarbonJoe

There isn't such a thing. Approved motors, batteries, bodies, yes. Chargers, no.

http://www.roarracing.com/?page_id=14

ROAR rules for 2010 state that the maximum voltage for LiPo is 8.40v for 2s, 4.20v for 1s. No wiggle room anymore. Also, a maximum charge rate of 1C.

CarbonJoe

Turn on your car and yank the throttle until you meet the rules. However, at some ROAR races, they may DQ you if you are over voltage when you come to the tech table. What I suggest is to have your own volt meter, and "calibrate" it to what the official meter reads. For example, if the official meter reads your pack at 8.42 volts, but your meter reads 8.40 volts, you better make sure before you go to tech your meter reads 8.38 volts (0.02v "offset" from the official meter).

Still Bill

iTrader: (16)

What charger do you have? Some higher end units are adjustable.

Chaz955i

iTrader: (5)

Joe, I'm using a charger similar to the small HobbyKing you have. Is there a way to set the max voltage or is it a matter of using a meter and running some off to make sure the charge is not to high?

Bubblehead

I was looking at the rules and it states 6 Nimh or 2s Lipo. Is there any mixing of batteries? Nimh running with Lipo

CarbonJoe

I just looked at the manual and didn't see anything to adjust or calibrate the cutoff voltage.

Bubblehead

It's a Thunder Power TP-610C.

CarbonJoe

To power the motor, bad idea! You could damage the LiPo...

Lots of people use different types between the main pack and the Rx pack.

Bubblehead

What I mean can I have Nimh in my car and you have Lipo's in your car?

Still Bill

iTrader: (16)

Hmmmm...TP makes good products so I am a bit surprised.

The online manual says that you can indicate percentage of charge. You could cut down on the charge that way. Read your manual for details.

Another thought is for you to check the voltage with another multi-meter. Theirs could be wrong.

Bill

CarbonJoe

Most bigger races don't allow that. One type only. Local clubs may allow that.

Ron Goetter

iTrader: (17)

You can turn off competition mode to lower finish charge voltage back to 8.40.

I would defiantly check your battery voltage with another multimeter to. I've seen multimeter be off by more then .10 before.