RCA charger connector snapped and stuck in battery charger connector

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NeedForSpeed   100 mW

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RCA charger connector snapped and stuck in battery charger connector

Post by NeedForSpeed » Mar 12 2018 5:15pm

The title sums this up. I plugged in the charger to my 72v Li-ion without it powered on and it made a massive spark, and when I pulled them apart, the male RCA monster connector from the charger snapped off and is now stuck in the battery's female connector.

Recommendations of what should I do?

After this incident, I'm a little wary of putting a new connector on the battery, fearful that the wires will touch when removing the old connector since I've never done that before. Anyone have recommendations how to take care of this? I was thinking of cutting one of the wires first, tape it off, then cut the other. Does it matter what order? Positive or negative?

Ditto with the charger connector.

While I'm at it, is there a connector people recommend over RCA since I'm doing this all over? Maybe something covered in lots of rubber so I don't turn my thumb black with soot :)
Custom Build
- Crystalyte TC-100
- Kelly KEB72601
- Battery: 72v 20ah, custom build, 20s8p, Samsung 25R ~150amp continuous
- EM3EV frame
- RockShox Domain RC 27.5" 200mm
- DNM rear suspension 220mm 550 lbs
- Magura MT5E Carbotecture Disc Brake w/motor cutoff
- Magura Storm HC Front Rotor 203mm
- Shimano SM-RT56 Rear Rotor 180mm

markz   100 GW

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Re: RCA charger connector snapped and stuck in battery charger connector

Post by markz » Mar 12 2018 5:35pm

Can you take pictures?

NeedForSpeed   100 mW

100 mW
Posts: 40
Joined: Dec 31 2017 12:25pm

Re: RCA charger connector snapped and stuck in battery charger connector

Post by NeedForSpeed » Mar 12 2018 5:55pm

Sure

Battery female:
battery1.jpg
battery2.jpg
Charger male:
charger1.jpg
charger1.jpg (144.23 KiB) Viewed 578 times
charger2.jpg
Custom Build
- Crystalyte TC-100
- Kelly KEB72601
- Battery: 72v 20ah, custom build, 20s8p, Samsung 25R ~150amp continuous
- EM3EV frame
- RockShox Domain RC 27.5" 200mm
- DNM rear suspension 220mm 550 lbs
- Magura MT5E Carbotecture Disc Brake w/motor cutoff
- Magura Storm HC Front Rotor 203mm
- Shimano SM-RT56 Rear Rotor 180mm

Voltron   1 MW

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Location: Santa Barbara CA

Re: RCA charger connector snapped and stuck in battery charger connector

Post by Voltron » Mar 12 2018 9:36pm

Thats a bummer... but the order you cut them apart doesn't matter. For the charging something like an Anderson Powerpole usually works pretty well, but there are many, all better than the RCA. I personally wouldn't spend the time trying to get the broken piece out.... practice on the charger connector first, as it won''t be live while you're messing with it like the battery will be.

Were you plugging the charger in to the wall or the battery first?

NeedForSpeed   100 mW

100 mW
Posts: 40
Joined: Dec 31 2017 12:25pm

Re: RCA charger connector snapped and stuck in battery charger connector

Post by NeedForSpeed » Mar 12 2018 9:55pm

The charger for this battery has an on/off switch, every time I charged it previously (a dozen times or so), I plugged the charger into the outlet, then into the battery (which gave a slight spark), then turned the switch on. I still don't know the correct order, but given this current situation, it seems to me I should have switched the charger on before connecting to the battery?

With a different charger for another battery I have, there is no on/off, so I always just plugged the charger into the outlet first, then into the battery, never had any issues with that one.
Custom Build
- Crystalyte TC-100
- Kelly KEB72601
- Battery: 72v 20ah, custom build, 20s8p, Samsung 25R ~150amp continuous
- EM3EV frame
- RockShox Domain RC 27.5" 200mm
- DNM rear suspension 220mm 550 lbs
- Magura MT5E Carbotecture Disc Brake w/motor cutoff
- Magura Storm HC Front Rotor 203mm
- Shimano SM-RT56 Rear Rotor 180mm

Voltron   1 MW

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Location: Santa Barbara CA

Re: RCA charger connector snapped and stuck in battery charger connector

Post by Voltron » Mar 13 2018 12:35am

Its a guess, but it might not have been anything to do with your plug in procedure. That kind of plug doesn't have a lot of separation between pos and neg.. It might have just jumped the air gap.

I had that happen on my fully charged 72v pack... I was unplugging it one time and the plug brushed past the aluminum of the battery rack and instantly put a gouge about an inch and a half long in it. The plug was insulated at the end, but not quite enough..
spark.jpg
spark.jpg (69.92 KiB) Viewed 534 times
Thats black carbon around the gouge....

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fechter   100 GW

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Re: RCA charger connector snapped and stuck in battery charger connector

Post by fechter » Mar 13 2018 3:22pm

I agree RCA connectors are not well suited to battery charging. I would use Andersons or XT-60s.

The damaged connector can come apart by unscrewing the knurled body from the end. Sometimes they are glued together so may be take some force to separate.
Fried battery2.jpg
Fried battery2.jpg (39.96 KiB) Viewed 503 times
Once you get the shell unscrewed, the wire connections should be accessible inside.

Agree it doesn't matter which wire gets disconnected first, but just be super careful not to let the two touch. It would be good if there was a way to disconnect the wire at the pack end first. If this is not possible, pick the wire with the most slack, cut it, and immediately tape the end to keep it safe.

The sequence does make a difference in most setups. If the charger is turned off when plugged into the pack, the pack will suddenly charge the output capacitors in the charger, which makes a big spark. The spark can damage the contacts. If the charger is turned on first, the caps are charged, so there is only the voltage difference between the pack and the charger, which makes a much smaller spark.
"One test is worth a thousand opinions"

NeedForSpeed   100 mW

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Posts: 40
Joined: Dec 31 2017 12:25pm

Re: RCA charger connector snapped and stuck in battery charger connector

Post by NeedForSpeed » Mar 14 2018 10:04pm

Thanks for all the advice, very helpful. Got everything disassembled and replaced with Anderson PPs since I already had some. Everything went smooth, and zero spark with new connection. Charging as we speak :D

Some pics -

Battery before - disassembled a bit
Image uploaded from iOS (1).jpg
After -
Image uploaded from iOS (2).jpg
Image uploaded from iOS (3).jpg
Custom Build
- Crystalyte TC-100
- Kelly KEB72601
- Battery: 72v 20ah, custom build, 20s8p, Samsung 25R ~150amp continuous
- EM3EV frame
- RockShox Domain RC 27.5" 200mm
- DNM rear suspension 220mm 550 lbs
- Magura MT5E Carbotecture Disc Brake w/motor cutoff
- Magura Storm HC Front Rotor 203mm
- Shimano SM-RT56 Rear Rotor 180mm

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fechter   100 GW

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Joined: Dec 31 2006 3:23pm
Location: California Bay Area, USA

Re: RCA charger connector snapped and stuck in battery charger connector

Post by fechter » Mar 14 2018 11:27pm

Much better :!:
"One test is worth a thousand opinions"

Voltron   1 MW

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Re: RCA charger connector snapped and stuck in battery charger connector

Post by Voltron » Mar 15 2018 7:39am

Better! And maybe being a nitpicker... but real heatshrink would be safer.. sometimes electric tape gets weird after a while and slides out of place.

Also, without the little roll pin that goes in the hole between the red and black plugs, one can back out just enough to get a bad connection and get hot.

I just had one melt down on one of my chargers that a gf was using, and who hadn't notice one half of the plug backing out a little... she didn't notice the droopy warped plastic housing of the plug for however long either that immediately caught my eye when I borrowed her bike, but thats another story :roll:

Sometimes the plugs wedge together enough the pin isn't needed, but sometimes not...

NeedForSpeed   100 mW

100 mW
Posts: 40
Joined: Dec 31 2017 12:25pm

Re: RCA charger connector snapped and stuck in battery charger connector

Post by NeedForSpeed » Mar 16 2018 12:45pm

Thanks yea that's good advice. I have some heat shrink, but forgot to put it on before putting everything together, and what I have is a little too narrow, I'll probably buy some bigger heat shrink soon to replace the tape before it gets too sticky.

I do have small pins in the Anderson PPs, so they're nice and tight.
Custom Build
- Crystalyte TC-100
- Kelly KEB72601
- Battery: 72v 20ah, custom build, 20s8p, Samsung 25R ~150amp continuous
- EM3EV frame
- RockShox Domain RC 27.5" 200mm
- DNM rear suspension 220mm 550 lbs
- Magura MT5E Carbotecture Disc Brake w/motor cutoff
- Magura Storm HC Front Rotor 203mm
- Shimano SM-RT56 Rear Rotor 180mm

Voltron   1 MW

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Joined: May 02 2013 4:53pm
Location: Santa Barbara CA

Re: RCA charger connector snapped and stuck in battery charger connector

Post by Voltron » Mar 17 2018 4:50am

Can you re-separate the plugs temporarily and line one up behind the other to get the heat shrink on?

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