How to measure a charge in a lipo pack - RC Groups
Sep 14, 2006, 09:53 PM
Registered User
Help!

# How to measure a charge in a lipo pack

The question sounds like commonsense, and maybe it is, but I am confused. It all starts with a 3 cell 1300 11.1 volt pack that I can't get to charge on my DN Power balancing charger. I know my charger has a safe guard built in to NOT charge if a cell is below 2.7volts. How can I tell this on my 3 cell pack? I have a volt meter, and when I measure the overall of the pack using the plug that I attach to my speed controller I get 9.82 volts. Assuming this is divided out my all 3 cells I would have roughly 3.27 per cell. Could this just be 2 highly charged cells and one bad one? Either way the pack has a balancing plug attached to it. How do I read in each cell independently? What does the red,blue,yellow, and black cables mean?

End the end this is a new pack that has only been bench tested, and I want to charge it up! Help!

Thanks (newbie converting from brush/nimh to brusheless/lipo)
Last edited by camxbad; Sep 14, 2006 at 10:02 PM.
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 Sep 14, 2006, 10:19 PM The Great Santini Since you mention common sense, look at this info on wiring of the pack: http://www.commonsenserc.com/page.ph...2c7bce9ae3b5d2
 Sep 14, 2006, 10:39 PM Registered User Interesting...never seen that part of their site before. So, blue and black are the positive/negative for cell one. When I hit it against my volt meter I am getting around 6.49? Is this because it is trying to pull voltage from a neighboring cell?
 Sep 14, 2006, 11:01 PM so i rewired it... Well usually red is at the positive terminal and black at the far negative terminal of course. Your blue-to-black is obviously measuring two cells, which means those two are 3.25V each or so. (Wire colors change... always best to figure out how your battery is really wired.) So what's blue-to-red (the other cell), and yellow-to-blue, and black-to-yellow?
Sep 15, 2006, 12:37 PM
Permanently Banned

# All Balance Leads R the Same

one side blk or red colored is either + or -, the adjacent lead and COMMON will read 3.7, 7.4. and 11.1 on the last lead, there is always 3.7V between any two adjacent leads

important thing to remember is to always remember to use the proper reversing adaptor which is supplied with DN Power 3S 2150 15C packs
 Sep 15, 2006, 12:39 PM Southern Pride Different vedors use different colors . https://www.rcgroups.com/forums/show...64&postcount=6
 Sep 15, 2006, 01:10 PM Permanently Banned amazing how some MFRs can't follow a simple color code black=0, common-0v , brown =cell 1-3.7V, red=cell 2-7.7v, orange=cell 3-11.1v, yellow=cell 4-14.8v, green= cell 5-18.5v, blue = cell 6-22.2v maybe they should GO BACK TO SCHOOL OR SELL HOT DOGS
 Sep 15, 2006, 01:21 PM so i rewired it... Back to school special, buy 2 batteries get a hotdog half off?
Sep 15, 2006, 01:43 PM
Sky Pilot
Quote:
 Originally Posted by camxbad Interesting...never seen that part of their site before. So, blue and black are the positive/negative for cell one. When I hit it against my volt meter I am getting around 6.49? Is this because it is trying to pull voltage from a neighboring cell?
Hi camxbad,

So, if you have 6.49v for two cells the third cell must be 9.82v - 6.49 = 3.33v. I have found that if you measure the adjacent terminals on most balance taps, it will give you the indivdual cell charge.

I'm not sure if this is recomended but it worked for me on one battery pack that I had mistakenly left plugged in on one of my planes. It went below the minimum that the charger would accept. What I did was to put the charger on NiCad charge for a few seconds until it brought up the pack voltage enough for the charger to allow it to charge as a lipo. Like I said, it only took a few seconds to achieve this. I then switched the charger back to LiPo and it charged as normal. I haven't had any problems with that pack so for but it could be that I'm lucky. IT was a fairly new pack.

Blessings, Terry
 Sep 16, 2006, 12:06 PM Registered User Great advice on figuring out the charge! Hall Woo was the winner though....I wasn't using the supplied reversing cable with the DN charger....hooked it up and wam! working! Thanks again for the advice -Cam

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