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-   -   AR9100 uneven battery use (https://www.rcuniverse.com/forum/jr-radio-spektrum-radios-116/8598117-ar9100-uneven-battery-use.html)

ulfsve 03-20-2009 03:35 PM

AR9100 uneven battery use
 
Hi,

I flew for the first time with new QQ 86" yak (50cc) where I'm using AR9100. I have 2 1800mAh LiPo with Spektrum power regulators.
Since it where first flight and first run for DA50 I did some running in before flight then I made 2 flights. In total equalling to perhaps four 12 minute flights.
When I charge LiPos the first one takes 270mAh and the second one 725mAh. Both batteries where new and fully charged.
Is this OK? shouldn't both get equally drained?
Is the consumption normal?
Any comments from other users of this config?


Best Regards,

Ulf Svensson
Sweden

KC36330 03-21-2009 09:40 PM

RE: AR9100 uneven battery use
 


ORIGINAL: ulfsve

.............with Spektrum power regulators...........
the battery with the higher consumption is connected to a regulator that has a somewhat higher output voltage from it, it's a common problem when using regulators that share a common bus on their output.

ulfsve 03-22-2009 04:09 AM

RE: AR9100 uneven battery use
 
Thanks.

This seems to be the case. One outputs 6.09V and the other 6.04V
Is this a problem or will it fix itself in the end?
Will one be totally drained befor the first is really used?

It is a bit strange though since both have been used.

Have anybody else used this configuration?

//Ulf

KC36330 03-22-2009 07:36 AM

RE: AR9100 uneven battery use
 
one will pretty much drain till the regulator cuts off due to low voltage. bad thing is this is well below the minimum voltage you should drain a Lithium battery. if you're going to use this type setup you should use a SmartFly Batshare and only one regulator.

ulfsve 03-22-2009 08:32 AM

RE: AR9100 uneven battery use
 
Yeah, this is what is worrying me.

But I did some additional testing. The AR9100 has one blue led for each battery showing usage.
At idle only the one coming from line with regulator with lowest voltage is used. When I start to move servos the other one also will light showing usage from both.
One "dirty" fix is to fly 5 flights and then switch batteries, that should work but should not be necessary.

Spektrum sells this configuration so it should work together it would be interesting to have some official statement from Spektrum.

//Ulf

KC36330 03-22-2009 03:10 PM

RE: AR9100 uneven battery use
 


ORIGINAL: ulfsve

Spektrum sells this configuration so it should work together it would be interesting to have some official statement from Spektrum.

//Ulf
they have, it's in the manual for the AR9100.


Using Dual Voltage Regulators
Spektrum offers a 10-amp (16-amp peak) 6.0-volt regulator (SPMVR6010)
specifically designed for use with the AR9100 PowerSafe. Important:
When using two batteries powered through two regulators, each regulator
operates independently and it’s common for one battery to be discharged
at a slightly higher rate depending on the condition of the battery (internal
resistance, voltage, etc.) and the tolerance of the regulators. This causes
one battery to discharge before the other and it’s important to check each
battery using a loaded battery tester (HAN171) at a recommended 1-amp
load before each flight monitoring the voltage of each pack and recharging
when the weakest pack reaches 40% capacity.

ulfsve 03-22-2009 03:15 PM

RE: AR9100 uneven battery use
 
Thanks,

I missed this.
So I think I will have to switch cables then after 3-4 flights.

Next time I will get servos operating directly on 2S LiPos.

//Ulf


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