Complete Guide to Lithium Polymer Batteries and LiPo Failure Reports - Page 51 - RC Groups
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Mar 26, 2010, 06:06 PM
Physics hate's my ideas
GreenAce92's Avatar
Netherlands! Oh boy haha... it would probably kill to ship haha
I would be interested in trying, I'm a fiddler (when will he learn!) but yeah shipping is probably a no go. Thanks for the idea or attempt though! I appreciate it! I am in need of a lipo charger at the moment lol, my little parkzone charger died
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Mar 26, 2010, 07:01 PM
Tally Ho!
kusunokimasahige's Avatar
Well this thing is really strange since it charged up untill yesterday and then it started to act funny...

KM
Mar 26, 2010, 07:04 PM
Physics hate's my ideas
GreenAce92's Avatar
Huh.... well if it is possible I suppose we could see what's up... why don't you want to fiddle with it? Green's not too much of a worry? Or are ya smart and quitting while you're ahead? haha (hence fires etc...)
Mar 26, 2010, 07:22 PM
Tally Ho!
kusunokimasahige's Avatar
LOL i hardly know anything about electrics and electronics, i teach history for a profession...

Ill see what it would cost to send the thing to the US, however i dont know yet which cables i can send with it since i dont yet know what the Utramat 14 of Graupner needs, will get that one coming tuesday...

I also tried the storage function just now, also same error.

KM
Mar 26, 2010, 07:26 PM
Physics hate's my ideas
GreenAce92's Avatar
Huh found absolutely nothing on the web? Perhaps a minor short somewhere or a burnt out part? Can you see or "smell" haha any physical damage?
BTW history eh? Nice
Mar 26, 2010, 07:41 PM
Tally Ho!
kusunokimasahige's Avatar
Nope i checked, no smell of any burnt out part, zilch !! also on the net, nowhere to be found is this problem, as Yoda used to say....

KM
Mar 26, 2010, 07:46 PM
Physics hate's my ideas
GreenAce92's Avatar
Haha fan of star wars too? Neat! Haha
Mar 27, 2010, 06:19 AM
Registered User
Axesea's Avatar
I've got a question which may have already been answered, but my internet connection is a poor one and searching for the answer is going to take a few days if not longer. So I apologize for not searching for it if it's already been answered.
I've been out of the hobby for a while and I need to refresh my memory about a 10s, 8000mah @ 37vdc lipo I have. It has been stored at 80% capacity for over a year. I'm not going to use this as a flight battery due to it's age, but I want to get my head thinking in battery logic again. (I'm going to order some new batteries to use.)
I want to discharge/recharge it a few times just to see what the capacity is after sitting for a long time.
This battery is made from two 5s3p, 18.5v battery packs wired in series to get the 37v. From my notes, I charge this at a cell count of 5s instead of 10s. I'm presuming this is because it is two separate packs connected in series, but each one still has it's balancing connection so each pack of 5 is balancing themselves at the 5s charging configuration.

I just bought an Ultramat 17 charger by Graupner. In the "warnings and safety notes" they are saying not to charge "batteries consisting of parallel-wired cells".

Question: How does this work out in large capacity packs that consist of batteries in connected both in series and parallel to form a pack?

In the charger I set the cell count to 5 to charge them, even though the charger indicates there are 9 cells. This is not accurate as the "circuit is not able to reliably detect more then 3 cells."

Question: To discharge the 10s battery pack do I adjust the cell count to 10s or leave it at 5s the same as charging?

I'm going to send them an inquiry, but their method of contact is snail-mail and it is a weekend!
Thanks for any input.
Mar 27, 2010, 10:44 AM
Space Coast USA
hoppy's Avatar
You have many options-
Here's one.
Charge and discharge each 5s3p pack separately as a 5 cell pack if you can.
You can't charge a 10s pack on a 5s setting if that was what you were trying.

The parallel cells in each 5s3p will self balance.

Before doing anything I would check the voltage of each series cell to see what the current condition is and than make a decision.
Mar 28, 2010, 11:52 AM
just keep flying!!! :))
hi guys, i tried to understand but i cannot

I have a battery 1300mAh 3-cell 20C

So how can i understand how long it will last???
And if it would be 30C it would last longer?

Any help appreciated
Mar 28, 2010, 12:06 PM
That's a funny word
Divide the total capacity by the current to get the time. Many like to limit to 80% of labeled capacity. If all else is equal a 30C will last no longer than a 20C, as it is a figure describing the max current capability of the cell.

Your 1300 mah pack may look like this:

1300 / 13 amps = .1 hrs or 6 minutes
If you use an 80% figure then it is .08 hrs or 4.8 minutes

1.3 amps would last an hr.
Mar 28, 2010, 12:38 PM
just keep flying!!! :))
thank you very very much, now i think i understand how they work.
really helpfull.
So if i have 5.2 amps the battery will be fully discharged in 15 minutes if i understand right.
Only one question though.
How can i measure how many amps i am using? It has to do with my motor? ESC? and maybe how much throttle i am using?
Last edited by maestros; Mar 28, 2010 at 12:44 PM.
Mar 28, 2010, 03:39 PM
Physics hate's my ideas
GreenAce92's Avatar
Wattmeter I believe. Something to do with the esc and motor connection
Mar 28, 2010, 04:18 PM
...the wind usually blows
av8r's Avatar
I've used one of these for years.
Last edited by av8r; Mar 28, 2010 at 08:25 PM. Reason: Link didn't work
Mar 28, 2010, 04:19 PM
Space Coast USA
hoppy's Avatar
Quote:
Originally Posted by maestros
How can i measure how many amps i am using? It has to do with my motor? ESC? and maybe how much throttle i am using?
The propeller determines the load (amp draw) of your system. Larger propeller=more amps, smaller propeller=less amps. The correct sized prop will draw the max (or less) amount of amps the motor is rated for. The ESC and battery are selected based on that amount of current draw.


You need one of these or something similar to measure amp draw.
http://www.hobbycity.com/hobbycity/s...E_Warehouse%29