Emag battery failure

[chops]

Bought an emag here about a month ago. After some charging and tuning it shot great. Ended up sending the frame and trigger off to get anodized since they were raw. (All other parts stayed with me) After reassembling the gun, the board lit up and the noid clicked as usual. I put the gun aside and charged up the battery. After the battery was done charging I reconnected it to the gun and smelled burning. It was extremely hot but luckily I was able to get it out of the housing quickly. It smoked outside for a few minutes but never fully combusted.

After some confused swearing I went back to the charger and found that it is outputting 26 volts. I'm no electronics expert but this is more than likely what killed the battery right?

What can I do to get the gun up and running again? I'm guessing the board is toast but hopefully the solenoid and hall effect are fine? Sci-Fi board seems like an easy option but where would I source a battery and charger nowadays? Maybe this is a sign I should just shoot mechanical..

[Jordan]

Not an Emag expert here but it is an 18v battery so I'm not super worried about your charger... I routinely charge automotive batteries at 16 to 18 V - they're 12V batteries - and alternators run at 14v, nominally, without causing issues with a 12V battery in the system.

Sounds like you have a bad connection somewhere causing a short.

Batteries are available from knownothingmags on AO, and Tunaman has chargers AFAIK, also on AO.

[Grendel]

If that is an original Emag battery I am surprised it lasted this long.

As Jordan said this is most likely a short and the short is most likely internal to the battery between jelly roll layers. That junction shunted too much current during charging and caused "thermal runaway". Testing a charger open circuit (not connected to a charging load) is not a good test of a charger and is almost meaningless. A charger meant for an 18VDC rated battery I would not surprise me to read 26VDC open circuit and I really would not be overly concerned at 34VDC open circuit. I will admit I do not have a lot of direct experience with Emags hopefully someone like superman will chime in who have way more experience with Emag batteries then I do but I do know batteries and charging circuits and when you have a battery catch on fire it usually is an issue with the battery by a far margin then a faulty charger.

[superman]

I would start by reaching out to ryan mingo as he is the one that makes those packs.

[Mini-Xmag]

Or you buy a new battery pack off the AGD website

[cougar20th]

Ill start with saying I completely disassemble my emag after every game. And clean it. Every part comes out. And i made one huge easy mistake that ended with the same results as yours. Im saying it this way because you recntly built the your gun.

In the spring while down in Baltimore for a game I cooked my battery. Yes I got it out of the housing. Otherwise theu would have seen a grown man cry. I found on disassembly of the gun after the incident that I had missed putting the plastic washer back on the inside of the frame where the nut for the positive battery connection is. This allowed for a immediate short.

Also make sure you have the plastic flanged spacer on the positive stud.

While I was scrambling to get my battery out of the gun it melted the wires on the battery and continued to short. Once out of the gun and on the ground it continued to burn for a half hour.


Washer inside frame




Flanged spacer. Flange on outside of frame

[Jordan]

I hate this battery setup for that reason.

[chops]

Turns out I'm an idiot on multiple levels.

I indeed missed putting that plastic washer back on the inside of the gun.



Also good point made about the charger being measured open circuit. 26V measured in that manner definitely does not imply 26v in the battery.

Is it possible to get the negative stud replaced on the frame? Mine is reduced quite a bit - I'm guessing a result from the recent anodizing?



Big thanks all around for getting this sorted. I'll try to reach out on AO to get a new battery.

[cougar20th]

Your not a idiot for forgetting the washer. It's a easy thing to miss. I've done it a couple times. But had always caught myself before it did it the time I shorted the battery.

I say try a new battery and see what your board does. I use a reflex board and it survived. Don't know if a agd board will.

[cougar20th]

I would contact tunaman on AO about the negative stud. I'm sure he has had to deal with them before.

[freedom]

for everyone that's mentioned tuna, he's the guy i would try and find. he's north jersey unless he's moved...

[cougar20th]

Tunas the man.

[superman]

Pretty sure i have a negative stud kicking around.

[SR_matt]

yeah I would echo that the charger testing on an open circuit probably doesn't tell much. if an 18 volt cell was actually charged to 26 volts I would expect it would have had a non passive failure on the charger. 18 volts is just the nominal voltage and it charges to about 21 volts for a full charge, 20+% overage would make it very, very unhappy very fast. not saying its impossible to fail after charging but yeah, I would be skeptical that it was necessarily the charger.

[tunaman5]

The AGD spec says not to re-use the negative battery terminal. The twisted "threads" get filled with aluminum and anno when pressing it in. I have found that you "can" re use them if you clean out the junk before pressing it back in.

[tunaman5]

The battery charger does indeed put out 20-26 volts which is normal.

[chops]

The AGD spec says not to re-use the negative battery terminal. The twisted "threads" get filled with aluminum and anno when pressing it in. I have found that you "can" re use them if you clean out the junk before pressing it back in.

Any tips for removing and replacing the terminal? I'm imagining a vise and punch type situation?

By the way, my Emag is this one. Ended up getting that frame anodized.

[chops]

Good news is that my Emag is powered up again. Battery from knownothingmags and a battery stud from bearded got my emag booted up again.

Bad news is that the hall sensor connectors snapped off at the sensor end and AGD can't find any more harnesses 😢 Anyone happen to know what type of hall effect sensor the Emag uses? I tried an A3144 type but it doesn't seem to be working. The connector for the hall looks like a JST SH 1.0mm so I guess I'll make a handful of them if I can figure out which sensor is needed.

[tunaman5]

Good news is that my Emag is powered up again. Battery from knownothingmags and a battery stud from bearded got my emag booted up again.

Bad news is that the hall sensor connectors snapped off at the sensor end and AGD can't find any more harnesses 😢 Anyone happen to know what type of hall effect sensor the Emag uses? I tried an A3144 type but it doesn't seem to be working. The connector for the hall looks like a JST SH 1.0mm so I guess I'll make a handful of them if I can figure out which sensor is needed.

The hall effect switch in an Emag was custom made at AGD and you wont find it anywhere. I have a couple left and then they are gone forever. The connector is NOT a JST. They are 1.25mm Molex and you need a 200.00 crimper to use them. Send me an email at tunaman5@verizon.net

[chops]

The hall effect switch in an Emag was custom made at AGD and you wont find it anywhere. I have a couple left and then they are gone forever. The connector is NOT a JST. They are 1.25mm Molex and you need a 200.00 crimper to use them. Send me an email at tunaman5@verizon.net

Sending you an email about acquiring a HES.

Yep - I learned the hard way that those connecters aren't JST SH. Ended up finding some pre-crimped Molex ones and I soldered on an A3144 hall sensor. Even with the trigger magnet all the way backed out, the HES was triggering without pulling the magnet closer. When the sensor was a bit further back without the plastic housing, the trigger did operate correctly. I imagine there's a sensor out there that's the right sensitivity for the Emag but no idea what to look for.