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Be careful of adapters

Old 05-30-2017, 06:58 PM
  #1  
SoCal Perky
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Unhappy Be careful of adapters

Hello,
I recently ordered a wiring adapter from my online shop whom I buy alot of R/C stuff from. I was using it on a parallel charging board with 2 other LiPo's already connected. When I plugged the third battery into the adapter, pop-sizzle-sizzle. The polarity of the adapter was backwards. From now on, I will be checking the wiring of everything possible before using anything no matter where I get it from, new or used. I did notify the shop of what happened and they did think me for bringing it to their attention and gave me a small store credit. Hopefully they will check their stock and make sure they don't sell anymore adapters with reversed polarity.

I guess the point is not to take anything for granted when it comes to electronics or electrical in our hobby. Be Careful Out There...

Perry
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Last edited by crxmanpat; 05-31-2017 at 12:58 AM.
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Old 05-30-2017, 07:35 PM
  #2  
ron_van_sommeren
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Don't forget to check polarity of new batteries as well. It happens ...
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Old 05-30-2017, 07:48 PM
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dereckbc
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Sorry about your trouble. However it does not even take a reverse polarity to fry a parallel charging board. All it takes is two batteries at a different SOC will do that. There is nothing to limit the current between batteries. The battery with a higher SOC will discharge into the battery with a lower SOC, and with nothing to limit the current will resort in burnt wiring and/or circuit board traces burnt up when the batteries equalize.
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Old 05-30-2017, 11:41 PM
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birdDog
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I would check the balancing circuits on the para board . Make sure you didn't smoke some of them. They are rather delicate.
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Old 05-31-2017, 12:58 AM
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I hate T-connectors for just this reason. So many times I've caught myself soldering one up backwards. But so far I've been lucky and caught every one.

And agreed with what birdog said about the parallel board. Make sure none of the balance traces got fried. I've done that a few times just plugging in the balance lead backwards.
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Old 05-31-2017, 04:22 AM
  #6  
dereckbc
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Originally Posted by birdDog View Post
I would check the balancing circuits on the para board . Make sure you didn't smoke some of them. They are rather delicate.
That goes without saying to some extent. The Balance Circuit traces are designed for milli-amps. Put a battery in parallel with a different SOC, and you will be 10's to hundred of amps flowing on the circuit traces and will burn them up. They will act just like a fuse and open circuit.

As an EE with 40 plus years of experience working with batteries, using a parallel board is just nucking futs.

If you run a simulator or math model makes it real clear what the problem is. Using a realistic possibility of say 2 x 3S 2200 mah 25C batteries. Each battery Internal resistance is roughly .015 Ohms. Now say one battery voltage is 11.1 volts and the other is 11.6 volts and you connect them in parallel. Equalization current is 33 amps. Not a problem for the battery wiring, but a serious problem for the Parallel Board circuit traces, especially the Balance Circuit Traces. They would not exist anymore and be gone with that puff of smoke you seen.
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Old 05-31-2017, 11:40 AM
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birdDog
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It goes without saying...to an electrical engineer.

I have been para charging for three seasons, with no problems. It takes attention to voltages and occasionally staggered connections.

Step one in para charging is, and always has been, similar starting voltages.
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Old 05-31-2017, 03:31 PM
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My only issue with using para boards is that I've shorted my Deans board twice by trying to plug in the balance taps. It was difficult to get those in sometimes as the wire leads are only 2" long on some of the packs. My solution was to buy 8" balance tap extension leads. I've not shorted a board since then.
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Old 05-31-2017, 07:52 PM
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dereckbc
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Originally Posted by birdDog View Post
It goes without saying...to an electrical engineer.

I have been para charging for three seasons, with no problems. It takes attention to voltages and occasionally staggered connections.

Step one in para charging is, and always has been, similar starting voltages.
That is a little vague. Yes it can be done if you know exactly what you are doing.

Saying similar voltages does not mean anything. I see recommendations of 0.1 vpc which is fine for say a 2200 mah battery, and if it is 3S = .3 volts or less and that limits you to roughly 11 amps equalizing current. That is fine on the main connector wiring say the EC3, not so much on the Balance Plug wiring and circuit traces on a Para Board.

However .1 vpc does not work on say a 5000 mah as now EQ currents are up to 25 amps. No problem on the main plug wiring, but Balance Plug wires and circuit traces are smoked. Now you are talking less than .05 vpc or .15 volts on a 3S battery.

There is no way a vendor that can make Para Boards safe for Joe Blow consumer. At least not one they could afford. Even if you know what you are doing, odds are you will miss something and eventually burn a Para Board up.

As for myself, I do it the smart way. I just buy a multi-port charger. Cost more but Joe Consumer proof, and I know what I am doing.
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Old 05-31-2017, 11:28 PM
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Anybody that does not know exactly what they are doing should not be para charging.

I'm not familiar with a multi-port that will push four 4000mAh 6s at 3c rate, as I currently do while field charging with a $17 deans style para board.

crxmanpat, balance leads are always the first to plug in and the first to unplug, followed by the specific batteries discharge lead, of course. And yes, I managed to bump a t-plug discharge lead in reversed polarity after the balance tap was hooked up. Smoked the traces. Now I watch the PL8 IR readings to ensure all leads are working, as well as occasional continuity checks.

Last edited by birdDog; 06-01-2017 at 02:23 AM.
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Old 06-02-2017, 03:18 AM
  #11  
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Originally Posted by birdDog View Post
Anybody that does not know exactly what they are doing should not be para charging.
I agree. Very few do. I do understand more than most and will not do it.

Originally Posted by birdDog View Post
I'm not familiar with a multi-port that will push four 4000mAh 6s at 3c rate
Nor do I, nor would I ever charge faster than 1C. But that is just me.
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