# Thunder Power 820cd charger question..



## RCMits (Jan 1, 1970)

Before sending the unit to be checked by TP, maybe someone can tell me if they have experienced this.. 

I have a new TP 820cd charger. When charging a 1-cell battery, even with the "cut off" set to 4.24, the charger on-screen display will show 4.179, and stop. When tested on a voltmeter after, the battery shows about 4.168. I tested with a different 610c charger, and it was able to bump it up to 4.19+ and always peaked around 4.2x.

It has the latest firmware 3.9 and I thought maybe it was a bad power supply or voltage from from the power source. I tried both a 14 amp radio shack, a 24 amp Protek, and a 30 amp bulldog power supply. Maybe because the AC line I used this weekend had ALOT of people daisy chained on it I got this low peak, but when I got home I tested a couple of batteries and they all show stuck at 4.179.

Now, if I toggle the sensitivity from 4.22 up to .24, and back down to 4.22, it'll put a couple more mah in.. but it never gets close to 4.2x

Any ideas?

Do I have something set wrong?

I am impressed how well and fast it charges, and the buttons and everything is so easy to use. just wondering why.. 

Anyone else??


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## kmberie (Dec 15, 2005)

I have an 820 that does the same thing only mine stops 4.10, if I power cycle it a couple times I can finally get it to charge to 4.2x 

Maybe we should post in Thunder Power product support to see if anyone has a solution. I have never updated my firmware since I purchased last winter, though it was something I was going to try.

Kevin


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## RCMits (Jan 1, 1970)

Of course, i can just send it in to have TP check it.. but I'm baffled.
I didn't want to "muck" up the TP page for the motors with a charger question.
Oddness..


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## THE DARKSIDE (Oct 7, 2001)

Yep. I also am having the same problem with the off-charge voltage listed at 4.197. I tried outsmarting the charger by bumping it to 4.24, but then it would overcharge the pack and it would not pass the volt meter in the tech area. Curious as to a fix for this

-E


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## VegasJim (Apr 15, 2003)

Mits - As I explained to you ate the West Coast Oval nats, I was not sure what was going on and to send me the charger to find out. We have not had this complaint so i wanted to check it out. It could just be a componit that lost calibration. but I need to look at it here. 

For anyone else that is having problems please use the support line or RMA system as we can not diagnoss problem completely over the phone.


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## RCMits (Jan 1, 1970)

yes yes  I know Jim, but I thought I'd ask if anyone else had a similar issue ...Always need to ask, just in case I was doing something wrong with the settings. It is a great product.
That way too, if others experience the same problem, maybe it was a manufacturing issues, calibration etc.. and TP can see maybe if there is a certain "production" run that had these problems.
Thank you as always Jim.


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## SuperTruck (Nov 27, 2010)

yes mine does it as well....stops at 4.20 although its set to 4.23 didnt do it at first, but has been doing it for a few months now, and only on port 1. Im just not thrilled about the 3 weeks of down time if i send it in:-(


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## kmberie (Dec 15, 2005)

Just so we are clear mine does not seem to be a calibration thing where it does not charge to 4.20 or 4.22 I could care less about the .02 of a volt but mine will actually switch over to the CV at 4.10 and the amperage starts dropping and I end up with a fully charged pack only at 4.10v. If i power cycle the charger a couple time I can get it to work fine. It does it on all cell types including my LiFe receiver packs they top out at exactly one 10th of a volt low, not a hundredth, a tenth. Again after power cycling a couple times it is fine for the day.

Jim if I send in what is the turnaround time? Sorta right in the middle of racing season so would like to not be without it for too long. And honestly I can deal with it if it just needs a power cycle or 2 when I first connect it. I have one GFX but hard to keep up with 2 or 3 cars and receiver packs.

Thanks for your support!


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