BK 9920 on 6s? - RC-Monster Forums

BL_RV0 · **BK 9920 on 6s? -** 01.16.2009, 11:29 PM

Do you think it would work? I want to go HV in my rustler...

Metallover · 01.16.2009, 11:51 PM

Got you a new avatar...

BL_RV0 · 01.16.2009, 11:55 PM

Metallover · 01.16.2009, 11:57 PM

Found this on google but didn't read through it.
http://www.rc-monster.com/forum/showthread.php?p=138734

BL_RV0 · 01.17.2009, 12:15 AM

Sweet, thanks. Basically the impression I got from that thread is that if I don't run it over 24v (IE not fully charged) I should be fine.

BrianG · 01.17.2009, 12:25 AM

Quote:

Originally Posted by othello

The german manual can be found here. I know this won't be of much use for you. But there is a note concerning using the BK ESCs at their maximum rated voltage:

Basic translation:
Be carefull when using the max cell count (20 cells) that you won't use them fresh from the charger. Those cells could be above 1.2V.

So the max voltage should not exceed 20x1.2V = 24v. A 6s lipo is at 25,2v fresh from the charger. This could mean trouble. As they also state that they can determine the max voltage the ESC was subjected to when you send it back to BK. Guess it's at your own risk. I know at least of one guy in germany who fried his BK 9920 with 6s lipos. Not on his firt run, but after a while. If i were you i would only use it with 5s max. It's never a good idea to push Esc to their voltage and/or amp limit.

Hmm, this would make me not want to run 6s. 24v is 4v@6s. So you'd have to adjust the CC/CV threshold to 4v to ensure that it works ok. Still, I'd go no higher than 5s to be safe.

lincpimp · 01.17.2009, 12:28 AM

Quote:

Originally Posted by BrianG

Hmm, this would make me not want to run 6s. 24v is 4v@6s. So you'd have to adjust the CC/CV threshold to 4v to ensure that it works ok. Still, I'd go no higher than 5s to be safe.

5s is about the max... I ran a 2wd emaxx with a 9920 and a 15l. Woked great, and i saw no reason to run any more voltage.

I still have the 9920 and 15l if anyone is interested... I will let them go cheap...

BL_RV0 · 01.17.2009, 12:32 AM

I don't have any 5s lipos though.

Metallover · 01.17.2009, 12:34 AM

http://www.rcuniverse.com/market/item.cfm?itemId=474469
there's your 5s lipo. Flightpower FTW!

BL_RV0 · 01.17.2009, 12:36 AM

I don't have enough money for that. I have to buy the motor for this conversion and the BEC. I think I have everything else.

Arct1k · 01.17.2009, 10:51 AM

The 9920 was free IIRC ;)

BL_RV0 · 01.17.2009, 12:12 PM

Yes it was- and a BIG thanks to Arct1k for "paying it forward!"