How to safely open turnigy 4s 5000mah hard case packs

They seem to keep restocking these lately so figure I would make a thread about how I open them. It is quick and safe and takes just a few minutes a pack.



This is the bit you will need to do it safely. The saw is not against the grain when it spins so it won't dig into the plastic. Unfortunately I threw away the packaging so I don't know the number of it but should be at any hardware store that has dremel stuff. Wrap the stem in kapton tape until there is about 1mm of the saw exposed. The plastic is just over 1mm thick so this keeps it from going too far in.


Cut three corners then pry up with a small flat head screw driver breaking free any extra plastic.





It is assembled as 2x 2s1p(crimp welded together) packs so you can unsolder them making 2x 2s1p packs or just leave them together.

Keep those cases. They work great for the end covers, so when you compress with electrical tape the end cells stay square instead of mashing to create rounded corners like shrink does.

John in CR said:

Keep those cases. They work great for the end covers, so when you compress with electrical tape the end cells stay square instead of mashing to create rounded corners like shrink does.

Click to expand...

Good idea!

silviasol said:

The saw is not against the grain when it spins so it won't dig into the plastic. Unfortunately I threw away the packaging so I don't know the number of it but should be at any hardware store that has dremel stuff. Wrap the stem in kapton tape until there is about 1mm of the saw exposed. The plastic is just over 1mm thick so this keeps it from going too far in.

Click to expand...

Exactly what I was looking to do. Would you by any chance have another picture or reference to that Dremel saw and how it is used? I'm thinking of looking for one, but just can't tell from the pic exactly what I'm looking for.

Many thanks!

It's been a few years and maybe they've changed the cases, but I remember opening mine quite easily and safely with a razor knife. Just get the tip under the overlapping edge where the 2 pieces join, and then with the blade parallel with the side so it pries the side out slightly from the cell just run the blade carefully down the each long length. Once the sides are loose just get one end done and the other will pop off when the top is lifted at the other end.

The way i opened them was smash one of the corners on wire exit end against the table or floor, holding it by the bigger of 2 case pieces (the one that has wire exits). Start gently and hit it harder and harder until it disintegrates. The hit has to be just strong enough, so that the 2 pieces of plastic that form the case crack apart from each other. Since most of the shock would transfer thru the pcb, the cells should be okay. Of course a more delicate way is prefered but in my experience the cells have been robust enough to be treated like this. I tried razor knife too but the risk of piercing the cells has prevented me from using this method.

I have built and ripped down quite a few packs..

The number #1 thing that gets me if I am being lazy...
Shorting a hot solder on the end of the pack.. Molten solder explodes, Dont need that solder sucker any more :O
I suggest wearing eye protection when de-soldering the pack :lol:

i do not recommend using a knife unless you can see where it is cutting. it is too easy to slip it into the side of the pouch.

i did not use a dremel, i used my table saw and set the kerf to be only as deep as the thickness of the plastic.

first i cut all the way around the top as close to the top as i could so it would clear any wires underneath. do the first cut slow and take it back off the saw as soon as it starts to examine the depth of the cut to insure you don't cut all the way through, then adjust the kerf a little deeper until it cuts through but leaves a mounds of melted plastic on the back side, that will make it free up.

then cut down the joint on the side. it should be in the middle so where you are cutting will be between pouches, but the depth of the kerf will keep you from hitting the pouch. then it pops open after you cut along the sides. maybe a little help with a screwdriver or plastic guitar pick like you use to open the laptop cases. BOL

dilkes said:

silviasol said:

The saw is not against the grain when it spins so it won't dig into the plastic. Unfortunately I threw away the packaging so I don't know the number of it but should be at any hardware store that has dremel stuff. Wrap the stem in kapton tape until there is about 1mm of the saw exposed. The plastic is just over 1mm thick so this keeps it from going too far in.

Click to expand...

Exactly what I was looking to do. Would you by any chance have another picture or reference to that Dremel saw and how it is used? I'm thinking of looking for one, but just can't tell from the pic exactly what I'm looking for.

Many thanks!

Click to expand...

I can't find it but I think it is this one

http://www.homedepot.com/p/Dremel-3-8-in-High-Speed-Cutter-199/100531863?N=5yc1vZgrZc1xy#specifications

if you decide that the 4S hardcase packs are the solution because they are cheaper, consider the fact that the pouches inside the hardcase packs are about 10% lighter in weight than the same 5Ah lipoly packs.

that accounts for the 10% difference in price imo. you just get smaller/lighter pouches in the hardcase packs.