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Old Sep 04, 2014, 12:57 PM
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v977 5x 520 mah Battery - Charger Potentially Dangerous!

http://www.tmart.com/Wltoys-V977-V93...t_p250064.html

Anyone who has got this set of batterys that come with the little USB charger. Keep an eye on your batteries.

The first time i used it not trusting it i kept an eye on voltages. I had 1 battery hooked up and after the light came on mayeb 5 minutes as i didnt notice, checked on a muiltimeter and the battery votlage was 4.24v!

After that, when i was charging all 5 seemingly taking a while (over 2 hours) i checked 1 battery. it was at 4.19. fine leave it another 15-20 minutes.... Light still not come on.. Check battery 4.21v. I check the rest and all at 4.21

I dont know if this charger actually cuts of the power or if it just turns on the light but i do not trust it.

If it doesnt cut off then you could find yourself with batteries that not only will be damaged but risk exploding!
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Old Sep 04, 2014, 11:59 PM
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FyreSG's Avatar
United States, CA, Monterey
Joined Apr 2012
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Parallel charging

It is just a parallel charging harness connected to a USB charger. I have been using one (without the USB charger) for a long time, but I connect mine to a computerized charger via JST-to-banana cable.

Over or under charging is common for USB chargers. They are made up of cheap components are are not calibrated. If you want precision, you need a computerized charger. Often, it lets you calibrate / fine tune the full charge level i.e. 4.20V. If you want full precision while charging multiple batteries, don't charge them in parallel. There are 3S-to-3x1S charging harnesses for such purposes. The computer will monitor each 1S cell of the 3S combo to prevent anyone from over charging.

The "fault" you have highlighted does not lie with the charger, but the fact that different batteries have different internal resistances. This results in uneven charging. While this is considered "normal", it may not be acceptable to some users.

Unplug the charger from the power source and allow the batteries to equalize the charge amongst themselves. They should have the same voltage after a few minutes.
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Last edited by FyreSG; Sep 05, 2014 at 12:07 AM.
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Old Sep 05, 2014, 05:03 AM
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Quote:
Originally Posted by FyreSG View Post
It is just a parallel charging harness connected to a USB charger. I have been using one (without the USB charger) for a long time, but I connect mine to a computerized charger via JST-to-banana cable.

Over or under charging is common for USB chargers. They are made up of cheap components are are not calibrated. If you want precision, you need a computerized charger. Often, it lets you calibrate / fine tune the full charge level i.e. 4.20V. If you want full precision while charging multiple batteries, don't charge them in parallel. There are 3S-to-3x1S charging harnesses for such purposes. The computer will monitor each 1S cell of the 3S combo to prevent anyone from over charging.

The "fault" you have highlighted does not lie with the charger, but the fact that different batteries have different internal resistances. This results in uneven charging. While this is considered "normal", it may not be acceptable to some users.

Unplug the charger from the power source and allow the batteries to equalize the charge amongst themselves. They should have the same voltage after a few minutes.
The charger that came with my v977 charges fine, it shuts off when charge is complete . Both batteries will meter 4.20v

This other charger im not sure if it even shuts of so i see that as potentially dangerous, maybe its charging to 4.24 before shutting of but i really dont want to risk leaving it plugged in to see if the voltage still rises.

What you said all makes sense, though it did manage to charge all the batteries to the same voltage despite not being a balance charger.

Anyway this is just to warn other people that this charger may damage batteries or at worst could caus an accident so to keep an eye on it.
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Old Sep 05, 2014, 10:42 AM
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Joined Feb 2007
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4.2 is pretty strong charge. Over that is over charge.
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Old Sep 05, 2014, 10:59 AM
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France, RA, Lyon
Joined Oct 2013
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Quote:
Originally Posted by dankar04 View Post
4.2 is pretty strong charge. Over that is over charge.
It is the max charge. Imax B6 charges @ 4.2, and then stops (4.19 exactly). I always charge @4.2, and then they go down to 3.75 / 3.8 after flight
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Old Jan 07, 2015, 12:21 AM
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I would NOT suggest using the parallel cable when charging more than one Lipo Cell as the USB portion has a charging circuit using a single MCP73831 which is only designed to supply a maximum of 500mA of charging current for ONE CELL ONLY.

I Repeat, the MCP73831 (and it's clones) are NOT designed to charge cells in parallel!

In fact, the MCP73831 Clone used in the USB charger portion is charging the cells to 4.4 volts which will vastly reduce cell life!

Get the 5-way charger found on ebay, it has five MCP73831 charging circuits, so each cell will get charged properly, and you avoid overcharging the cells with the least discharge which is what happens when you charge them in parallel with a single MCP73831.

Throw away the parallel cable, and the USB charger cable that came with it, they will not properly charge your cells, and they will damage them.
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Old Feb 12, 2015, 05:58 PM
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United Kingdom, England, Egham
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Hi,

What's the battery connector on the V977 called? It's hard to look for cables without knowing its official name.

Thanks.
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Old Feb 13, 2015, 08:40 AM
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it's OK I've just found out they're called micro losi
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Old Feb 18, 2015, 01:57 AM
Crash and learn
United States, PA
Joined Dec 2011
1,996 Posts
Five LEDs, likely five chargers, one for each battery
Five Ports Balance USB Charger for V977 V930 3.7V Batteries
http://www.banggood.com/Five-Ports-B...-p-967816.html

I have one similar to this for V911-Pro and it does act like four independent chargers.
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Last edited by Ribble; Feb 18, 2015 at 02:03 AM.
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