wow didn't expect that how did it happen

[Maxxman]

I gave my bl maxx its first run and pulled a wheelie :) and landed on the roof and bent rear body post. flipped it onto its wheels and nothing so looked down and heard a hissing felt the batteries and were boiling hot after less than a minute.

I managed to desolder the plugs on the quark and batteries and they also
leaked over the chassis and were reacted with the polycarbonate shield, (that took a while to figure out), which i used to protect the bottom of the g-maxx chassis from scrapes, it just trapped the leaked battery stuff, not sure what it is, as it did somecrazy thing to the chassis.

e-maxx had 2 ib 7.2 3800 (i was just testing it) quark 125, single speed, feigao 8xl, gearing 20/51
UE drivetrain and strobe slipper.

i think that it happened because of the amp draw but i am not sure.
is it a good idea to use any NImh or Nicads with this set up and if so will it desolder the connectors like it did this time.

[silentbob343]

Originally Posted by Maxxman

I gave my bl maxx its first run and pulled a wheelie:) and landed on the roof and bent rear body post. flipped it onto its wheels and nothing so looked down and heard a hissing felt the batteries and were boiling hot after less than a minute.
[IMG]C:\Documents and Settings\Matt\My Documents\My Pictures\PictureProject\0016[/IMG]

C:\Documents and Settings\Matt\My Documents\My Pictures\PictureProject\0016

[IMG]C:\Documents and Settings\Matt\My Documents\My Pictures\PictureProject\0016[/IMG]

i managed to desolder the plugs on the quark and batteries and they also
leaked over the chassis and were reacted with the polycarbonate shield, (that took a while to figure out), which i used to protect the bottom of the g-maxx chassis from scrapes, it just trapped the leaked battery stuff, not sure what it is, as it did somecrazy thing to the chassis.

[IMG]C:\Documents and Settings\Matt\My Documents\My Pictures\PictureProject\0017[/IMG]

e-maxx had 2 ib 7.2 3800 (i was just testing it) quark 125, single speed, feigao 8xl, gearing 20/51
UE drivetrain and strobe slipper.

i think that it happened because of the amp draw but i am not sure.
is it a good idea to use any NImh or Nicads with this set up and if so will it desolder the connectors like it did this time.

heh you can't use img links to files on your PC, they have to be hosted someplace.

You can upload them as attachments if you can't host them online.

If I had to guess it might have do to the draw with that gearing.

[Maxxman]

yeah i realised that pretty quick
and was going to try the attachments but couldn't decide what picture to use.

it was only at that gearing as i decided to try those packs as opposed to dual 8.4V packs at the last minute.

would i be right in saying that Dual 8.4v packs would be alright with this gearing. If not i have have a 16 tooth mod1 gear that i could use otherwise.

The Quark and 8XL should be a good combo in a maxx. If it were way overgeared, I would imagine that the esc would have protested in someway.

It sounds to me like you had a battery failure, probably due to a short someplace.

The motor leads on the Quark are exposed so something could have slid in there and caused the short. Have you tried it again with a fresh set of batteries?

It takes a lot of heat to desolder a connection. What was it that leaked? Are you saying that the batteries leaked, or did the solder flow off of the joints?

[Maxxman]

no i haven't tried it with new batteries yet as it apart my table.

I bought the batteries a month or two ago and kept them topped up charge wise and this was the first run that they had after i recharged them.

i just had a look and there was nothing between the motor leads and there was some little balls of solder on the chasis plate as well as a strange substance spread out on the bottom of the chassis plate and my polycarbonate gaurd that was attached to it.

i am pretty sure that the battery or batteries leaked as the shrinkwrap on the cell is not there in parts and the metal in exposed. At the other end there are bits of balck over the shrinkwrap, orange lumps on it as well and where the shrink endsin the end of the cell it is black underneath it

[rchippie]

Originally Posted by Maxxman

no i haven't tried it with new batteries yet as it apart my table.

I bought the batteries a month or two ago and kept them topped up charge wise and this was the first run that they had after i recharged them.

i just had a look and there was nothing between the motor leads and there was some little balls of solder on the chasis plate as well as a strange substance spread out on the bottom of the chassis plate and my polycarbonate gaurd that was attached to it.

i am pretty sure that the battery or batteries leaked as the shrinkwrap on the cell is not there in parts and the metal in exposed. At the other end there are bits of balck over the shrinkwrap, orange lumps on it as well and where the shrink endsin the end of the cell it is black underneath it

Buy looking at the pic it looks like your cell shorted against the chassis. This happened to me with a CF chassis & it cought fire. There should have been some clear heat shrink on there. The blue stuff from the factory is not enough to protect the cell.

[Finnster]

Two things:

1. Personally I think the gearing is too high. I ran 15&16/51 on my ERevo w/ emaxx tranny. A 20t is quite a step up form that.

2. That cell is def cooked, and most likely shot. Investigate a bit, but it looks like those 2 cells shorted, esp if this was sitting on a alu chassis.

Hard to tell more than this from the pics and info provided

[Maxxman]

yeah i do think you are right with the gearing but i was going to run 16.8V but then chose 14.4V in the end. didn't think to change pinion as i just wanted to drive it. My bad never mind.

yeah i think it did short out against the aluminuim chassis as you both have mentioned. prolly happened when it landed on the roof.

it didn't have any clear heatshrink on it.

i got it via Mike from Maxamps and because everyone rates their batteries so highly didn't do anything about it.

the picture isn't great but i spent sooooooooooooo long getting it small enough to be sucessfully uploaded i kind of gave up in the end and took it as a victory that i got it on here. So bad at computers.

[Dafni]

+1 for short against the chassis brace.

[Maxxman]

They are in exact place that you don't want them to be, if you run side by side Nicad's or Nimh's,
But all you can do is cover it with an insulator which looks kind of stupid and ugly. Or put heatshrink around the entire pack and hope that work which is what i should have done in the first place but didn't know that i needed to or what would happen if i didn't. I.E. This

[suicideneil]

The learning curve is steep in this hobby, but we all learn from our mistakes.... usually. You can get the shrink wrap stuff from towerhobbies- very cheap & clear, so it doesnt look ugly and does a good job of protecting the cells. I too blew up a cell in a 6 cell pack not too long ago, but that was from pure over gearing in a very heavy truck; its worth having a look at BrianG's speed calculator if you havent already.

[crazyjr]

I had a similar thing happen resulting in a battery explosion. I was runing some 4.4k maxamps 6 celled packs in my G2R revo, after about a minute i saw the truck hesitate for a split second, then about a minute later I saw black smoke pour out and a shotgun like bang, one cell nearly turned itself inside out and others in that pack were leaking, the other pack got real hot but none leaked or vented. I later determined it shorted, because i assumed that maxamps used shrink on the individual cells, when he did not. Did you have heat shrink on the cells for protection?

that is part of the reason i went to lipo's, if something happens its because of the battery or design, not due to a external short

[suicideneil]

Originally Posted by Maxxman

it didn't have any clear heatshrink on it.

Nope.:007:
The maxamp cells are rated highly, but any and all cells require shrink wrap over them to protect the bare connections, and keep them clean/dry/dirt free.

[crazyjr]

sorry missed that

[suicideneil]

Hehehe. Im wondering if its just those two cells that are toast, or whether the whole pack if cooked- would suck if it was .