Zippy Flightmax Lipo??

[jsr]

They're fine batteries. Just AVOID the 4000mAh Flightmax 2s Hardcase ones. Those are ok if your application won't demand more than 50-60A continuous, but the terrible soldering makes them far below their rated "100A". Stay away from those and you should be fine. I ordered 6 packs and ALL 6 packs opened circuited.

[Metallover]

Originally Posted by jsr

They're fine batteries. Just AVOID the 4000mAh Flightmax 4s Hardcase ones. Those are ok if your application won't demand more than 50-60A continuous, but the terrible soldering makes them far below their rated "100A". Stay away from those and you should be fine. I ordered 6 packs and ALL 6 packs opened circuited.

Are you talking about the 2s? I've never seen the 4s..... The soldering issue is supposed to be fixed also...

[lincpimp]

Originally Posted by jsr

They're fine batteries. Just AVOID the 4000mAh Flightmax ss Hardcase ones. Those are ok if your application won't demand more than 50-60A continuous, but the terrible soldering makes them far below their rated "100A". Stay away from those and you should be fine. I ordered 6 packs and ALL 6 packs opened circuited.

Did you fix them? Or send them back? I would like to see the internals of those packs...

I ordered 4 of the 5000 2s 20C packs. 1 has a bad cell that I'm trying to revive. The good packs are nice, but you're screwed for returns. HC will not do anything at all without returning the pack... on your own dime.

[jsr]

Originally Posted by lincpimp

Did you fix them? Or send them back? I would like to see the internals of those packs...

Yeah, I opened up the hardcase on every pack and resoldered the cells. After doing so, most of them continue to re-open under any load near their "100A" rating. Since then, I use them for setups that don't draw as much current, but I've had them open on a 60A setup (that never got past just warm, so I doubt it was even drawing 60A). The tabs on the cells does not allow solder to wet. This was the case when they were first put together and also when I resoldered them. I even sanded down one of the cell tabs that didn't wet well to get clean metal and it still wouldn't take solder. Because the tabs don't wet solder very well, most of the joints that opened were because the factory knew this and all they did was blob enough solder so that it made a pressure joint against the tab (meaning the solder blob just pressed against the cell tab to make electrical contact). Any mechanical vibration (like in a RC truck) or heavy thermal stress (like big current draws heating up a crappy high-resistance electrical connection) would easily open a pressure connection. I took a picture of the solder joint before, but am too lazy to find it. I posted it on RCU or somewhere.

[squeeforever]

Originally Posted by jsr

Yeah, I opened up the hardcase on every pack and resoldered the cells. After doing so, most of them continue to re-open under any load near their "100A" rating. Since then, I use them for setups that don't draw as much current, but I've had them open on a 60A setup (that never got past just warm, so I doubt it was even drawing 60A). The tabs on the cells does not allow solder to wet. This was the case when they were first put together and also when I resoldered them. I even sanded down one of the cell tabs that didn't wet well to get clean metal and it still wouldn't take solder. Because the tabs don't wet solder very well, most of the joints that opened were because the factory knew this and all they did was blob enough solder so that it made a pressure joint against the tab (meaning the solder blob just pressed against the cell tab to make electrical contact). Any mechanical vibration (like in a RC truck) or heavy thermal stress (like big current draws heating up a crappy high-resistance electrical connection) would easily open a pressure connection. I took a picture of the solder joint before, but am too lazy to find it. I posted it on RCU or somewhere.

Thats because your not using the right type of solder and I'm gonna guess your not using flux as well...

[phildogg]

Originally Posted by jsr

They're fine batteries. Just AVOID the 4000mAh Flightmax 2s Hardcase ones. Those are ok if your application won't demand more than 50-60A continuous, but the terrible soldering makes them far below their rated "100A". Stay away from those and you should be fine. I ordered 6 packs and ALL 6 packs opened circuited.

I bought 4 of the 2s 4000 25c hardcase (new version with better solder ) They run great for me.. I have run them in my 1/8 ofna buggy with mmm/2200 combo on 4s and they performed great.. runs right around 40 mph with them.. never run hot either. great in the rustler also.. mine are the ones tey have now seems they fixed the solder issue and made a update on the site about it.
phil
phil

[Jason]

I ordered these one for my slash :

http://www.hobbycity.com/hobbycity/s...idProduct=8583