Dynamite Reaction failure?

[swampguts]

Let me preface this with the fact that I'm new to lipo and RC in general. I've had two Dynamite packs have the middle wire on the balance lead pull out from the pack while driving a Granite Voltage. I don't know how common this is, if it's Dynamite or me, or if it's fixable, but if I connect to my charger with that lead all kinds of alarms start going off. And obviously I can't see if the cells are getting wonky. They are less than three months old.

It's weird, I have the same batteries in my new Outcast, no issue so far. I like the performance, and the size is perfect for both Arrma trays, but if this is common to Dynamite or RC in general I'm at a loss.

Is there any fix for this? Anyone else experiencing this?

 

[olds97_lss]

A buddy of mine used to have it happen all the time on his gens-ace-r-spam packs in his talion. I don't know if later talions have the balance plug slot that my outcast has or not, but his packs had those big "protection" plugs on it, so they wouldn't fit in there anyway even if he did have it. Instead of strapping the balance taps down, he just let them flop around. Well, they are made of wire. Wire can only bend so many times before it breaks, and usually, it breaks where it's soldered because the wire is hard there, which is right at the battery tabs. I resoldered his balance leads probably 6 times last summer. He refused to get some velcro and wrap the ends of the packs to hold down the balance taps.

On my outcast, I use the little balance plug holder. On my ERBE/SavageFlux, the balance wire goes inside the battery box and is tucked away, so it doesn't move around much. In my smaller trucks though, it would flop around like an idiot, so I'd wrap the end of the pack with velcro to hold that wire down, then I'd put the pack in the truck.

So far, in 2 years I've only had 1 end get ripped off. It was when the battery door of my erevo popped open in a crash and the pack came out, the plug got hung up inside the battery box and ripped off.

 

[swampguts]

So repair is possible? How safe is that? I just crack open the hardcase? Sorry for all the questions, I'm just nervous. Haha.

 

[olds97_lss]

It's harder with a hard case... with a soft pack, you just have to cut through the wrap and tape, then clean the joint, solder it and retape it with gorilla tape as best as you can.

The hard cases are either glued or ultrasonically welded (plastic is melted). So, getting into them is harder... not sure what I'd recommend.

I had SMC lipo's that I tore apart to make 3S packs out of old 2S packs. It's a nerve wracking thing to cut at a plastic case knowing if you go 1mm too deep, your cutting into a hermetically sealed chemical pouch (lipo cell). But I don't know another way to "fix" it. In the end, your going to have to tape the case back together. For myself it was worth the risk vs throwing the packs away.

Now, I'm not saying do this, but... I used a thin dremel cutting wheel on relatively low speed with very light pressure to work my way around the seam of the case. Grind a little, look for shiny, grind a little, look for shiny. When you see shiny, stop, that's the lipo cell. Then do the next inch or so. Work your way around it.

My packs had double sided tape on the top/bottom of the cells themselves, so they were adhered to the case halves. Required some pulling to get the case off even after cutting all the way around. Then you fiddle with the tape/sponge bits to near the wires to get at the cell tabs. Clean it off the best you can with a bit of DA and a q-tip, figure out which tab you need to solder to, put a little flux on it and strip the tip of the wire to flux/tin it. Then solder it back where it goes.

Then put the sponge bits/tape back how they were as best as you can, wrap it with at least one wrap of gorilla tape, then put the case back together and wrap it with a few wraps of tape.

This was one I built out of my 2S packs before I put the sponge bits and tape on it:

The top one is the end result:

The top one here is what I started with (except they were older 7200mah):

The middle one is a hobbystar 54003S and the bottom one is the 7200mah 3S pack I built.

On the plus side, once you do it, if they break off again, it will be easier to get to it to fix it next time.

 

[swampguts]

I don't know if you can make it out, but it looks like it's just little tabs holding it together.

 

[olds97_lss]

Well, that would make it a lot easier. Poke at it with something, just be careful to not go all they way through. Squeeze it hard at the seam to see if it gives/pops/cracks. If it's glued/melted, it likely won't pop/crack. If it's just clipped together, then it will give some.

 

[swampguts]

Okay. You've convinced me to try it. I think I have a couple free hours tomorrow afternoon, so I'll pick up an iron, solder, and flux. Anything you recommend I practice on before I try my hand at this?

 

[olds97_lss]

Okay. You've convinced me to try it. I think I have a couple free hours tomorrow afternoon, so I'll pick up an iron, solder, and flux. Anything you recommend I practice on before I try my hand at this?

Someone else's lipos?

Get an iron that is 60W or more. May not need it for the balance wire, but it may come in handy later for soldering plugs on. Much less than 60W won't touch AWG10 wire or the solder that comes on the main lipo tabs. I got a cheap 100W for the big stuff and a cheap amazon admustable 60W for smaller stuff. Spent about $45 for both of them. I should get a variable power switch thing for the 100w as it works better since it retains a lot of heat.

 

[JDM]

Had same problem with Dynamite batter 3s lipo. When i plugged it up to charge the charger said reverse polarity. I opened it up and one of the tabs to the cell is loose. It works if I hold it all together a certain way. Called Horizon they are letting me buy a new one at there cost.

 

[swampguts]

It was literally just snapped together. I'll post some pictures later. There's about 5/8 of an inch of wiggle room for the cells inside the case, lengthwise. Is that normal?

 

[olds97_lss]

It was literally just snapped together. I'll post some pictures later. There's about 5/8 of an inch of wiggle room for the cells inside the case, lengthwise. Is that normal?

I don't know what's normal, but there's open space in my SMC hard cases. They keep it from banging around in there by using double sided tape or adhesive to glue the top and bottom cells to the case itself. The cells are also all glued together. So, nothing in there moves around even with the space.