Always...ALWAYS Verify Your Charing Current PSA

[Monkey Wrench]

Bought a new charger...got a little ahead of myself and did not notice my charging current for a six cell NiMH pack was set to 15A instead of 1.4A.

So this happened!

 

[tntpoof]

did you have the marshmallows handy with chocolate grams?Always check check and recheck during charge.

 

[bill_delong]

"Charing" current... literally!

Man that sucks!

When I was a kid back in the 80's we didn't have any fancy chargers to limit the current. We used mini jumper cables and hooked up our NiCd packs directly to a full size12V car battery. We knew it was fully charged in about 5-10 min when the pack got warm then manually disconnected the jumper charge cable. No doubt I was pushing more than 14A into a 600mAh NiCd, basically this was the "charge cable" we used here:

Then they started to come out with a fancy timer but current was in the 4A range with a 15 min max:

eventually they would release current peak detection chargers later on which was incredibly safer but limited to 1C charge rates, boo

 

[Jamr]

Where are the temp sensors battery charging manufacturing companies?
I guess they are waiting for someone to die and a hefty law suit to add them.

Glad no one was hurt. Any damage to home or area?

 

[Doom!]

I'm sure that smelled pleasant. Sorry about the battery, but at least it wasn't worse.

 

[Monkey Wrench]

did you have the marshmallows handy with chocolate grams?Always check check and recheck during charge.

Hah! No, and thankfully just left a scar on an old card table. Lesson learned for sure!

Where are the temp sensors battery charging manufacturing companies?
I guess they are waiting for someone to die and a hefty law suit to add them.

Glad no one was hurt. Any damage to home or area?

No, thankfully! Just a nasty smell, a pissed wife and a charred card table.
Just me going all "Tommy Boy" on the new charger and not paying attention. Need to slow down and read the entire manual!

That said, charged another pack at 1.4A and even it got a bit warm. I never noticed that on my old charger, but it may be that the old one never charged at that rate. That normal it gets a bit warm as it charges?

 

[Chubaka]

Sorry to hear that. On the positive you didn't lose your house....

 

[Tunedfrog]

I'm so glad you didn't burn anything down other than the battery.

 

[Greywolf74]

It should get a little warm but the warmer it gets the more it shortens the life span. Ideally you want to charge NiXX packs with a temp sensor so the charger can regulate the current based on the packs temp. This will ensure you get a full charge that wont prematurely shorten the packs life span. If you're not using a temp sensor I wouldnt charge a nickle pack at more than 1/2C and if I have time to spare 1/4C

 

[tudordewolf]

Where are the temp sensors battery charging manufacturing companies?

SkyRC's B6 and its derivatives (B6 mini, B6AC) have an optional external temperature sensor you can use to terminate a charge. It comes with a Velcro strap so it's easy to wrap around the battery.

 

[Greywolf74]

Virtually all chargers come with a temp sensor port, just most of them dont come with the sensor, you have to buy it separately

 

[Monkey Wrench]

It should get a little warm but the warmer it gets the more it shortens the life span. Ideally you want to charge NiXX packs with a temp sensor so the charger can regulate the current based on the packs temp. This will ensure you get a full charge that wont prematurely shorten the packs life span. If you're not using a temp sensor I wouldnt charge a nickle pack at more than 1/2C and if I have time to spare 1/4C

Sorry @Greywolf74 , but what do you mean 1/2C and 1/4C? I probably should know that, but....

 

[Greywolf74]

Sorry @Greywolf74 , but what do you mean 1/2C and 1/4C? I probably should know that, but....

If the pack was a 1600mAh pack then 1C would be 1.6A, 1/2C would be .8A and 1/4C would be .4A.

The C rate at which to charge NiXX packs kind of depends on the size of the cells too. a big 3000mAh pack you use in a car will charge fine at 1/2C but if your trying to charge a 4AA 1600mAh receiver pack I wouldnt go above 1/4C. The smaller cells get hot faster. I've found that if you try and charge NiXX packs too fast they'll either get to hot (think shortened life span) or they'll hit a false delta peak and the charger will stop charging them prematurely thinking they are done charging when they really arent.

 

[Monkey Wrench]

If the pack was a 1600mAh pack then 1C would be 1.6A, 1/2C would be .8A and 1/4C would be .4A.

The C rate at which to charge NiXX packs kind of depends on the size of the cells too. a big 3000mAh pack you use in a car will charge fine at 1/2C but if your trying to charge a 4AA 1600mAh receiver pack I wouldnt go above 1/4C. The smaller cells get hot faster. I've found that if you try and charge NiXX packs too fast they'll either get to hot (thinking shortened life span) or they'll hit a false delta peak and the charge will stop charging them prematurely thinking they are done charging when they really arent.

Ah, gotcha. These are smaller 6 cell packs going into a RC18T. 1600 MaH