Battery concern

[wibblywobbly]

There was a discussion on here a while back about the cheap Nimh batteries that were on Ebay, which do not appear to be anything like the Mah rating that is on the label. I have 3 of the 5000mah ones and none of them will run a tank for more than 20 mins.

I have literally just come off the phone from chatting to a friend, he happened to have one on charge while I was talking to him, all of a sudden he yells, and the phone goes dead. The battery had caught fire while we were talking and he had to grab it and throw it out of the window!

I have never heard of an Nimh going up in smoke before. If he had left that on charge and gone out... ??

The moral of the story is...if something looks too good to be true, it probably is.

[mike1268]

Yep, I've got 3 also. Silver grey ones. Only charge to about 1000 and are meant to be 5000's. If this is happening with NIMH, I'm never buying a LIPO from ebay ... lol

[ausf]

I've been making my own NiMH packs by getting the individual cells with tabs and soldering them together.

They're all 1.2 volts, but the size can range from AAA to C, so you can really design something for tight spots if you want. The capacities I buy range from 1800 to 5000 and a quality cell like Tenergy can be found in the $2-4 range.

I suspect there are people out there using low quality, low capacity cells and making up packs, calling whatever you want to hear.

[atcttge]

I have two of those 6800mAH I think NiMHs from eBay, yes the grey ones. I had already purchased those before reading one of the vendor warning discussions here. Since then, I only charge these at half the capacity. Now that I'm using LiPos, I only use these NiMHs for testing electronics, spray painting sprockets, and such....

I thought the prices of those batteries were a good deal. Until I found a legit RC shop near home that sells legit LiPos at the same capacity as those fraud eBay NiMHs at a cheaper price.

[SteelBird]

I have a question regarding battery. I have two tanks with 3 battery packs, two of them are stock battery with one NiMH and one Li-ion, the other is an after market 4500mah. I don't like to remove battery for each charge. So, I made a charging port on the tank's rear panel, and charge directly. I never remove the battery since then. That's the story of the NiMH battery; however, my new tank has a stock Li-ion battery. I'd like to know if it is good/safe to keep the Li-ion battery inside the tank all the time?

[mike1268]

Any lithium based battery should really be charged in a fire resistant bag/box. When they choose to burn out, there is no stopping them. Some people user metal boxes, like an old ammo box. I use a fire safe with is a fire proof bag. it wont stop it damaging the surface you are charging on, but it will help to contain the fire if it should happen.