JohnP2

One thing I'm sill learning are the different battery types/setups. To date, I've only used AA batteries for everything (save for the 7.2 nimh for my Savaage's roto-start). Because the D8T won't accept AA batteries, I shelled out 30 bucks for a new 1700 mah OFNA hump pack. It worked fine, and decided to charge it tonight due to it going to below 5.2 volts. I put it on the new DurartraxOnyx100 charger I have, set it to the correctcurrent (per the instructions and mahvalue of the battery). About an hour later, I see it is on trickle charge, so decided to plug it back in.

POOF! As soon as I plugged it in, a spark and then smoke from my battery housing. I opened my battery housing and the hump pack was melted somewhat were the wires connect. I decided to touch it, and then the flames started! I'm thinking "this can't be good". Of course now when Iplug it in- nothing.

My question: is this servicable, or have I screwed the pooch here? In other words can I fix this, or is the battery literally fried? Also, does anyone know what caused it? I assume it was "over-charged", but the charge current was on 2A (which per the instructions was in range for the mah value).

I'm kinda hoping it will cool off and then work tomorrow, but not holding tight to that wish. ;-(

echthelion

oh man did you walk under a ladder or break a mirror?

i never charge my hump packs over 0.8amps i like to charge nice and slow
if i was you id buy a better charger... buying one that does more then you need saves you money in the long run.

ive been using this for 6months and im very happy. http://www.amainhobbies.com/product_...rger-6S-6A-50W

i did what you did and got a cheaper charger to do what i needed at the time but after awhile i out grew

HerrSavage

Very good advice.

I just bought a cheap charger for getting started with lipos, and as almost always with RC, it would probably have been better to spend a bit more up front..

My guess is your battery is toast. Get a new one and charge it at lower power..

nitrosportsandrunner

post pics of battery!
but it does sound like its done for.
Its possible the battery was defective to start with.
There could have been a bad cell or connection.
It is rare to catch a nimh pack on fire. Generally, this only happens if they are overcharged/charged too fast or are put on a model which trys to draw too much current from them.

JohnP2

It was kinda cool seeing it flame up like it did. If it's toast, at least I got a bit of a show.

A few things:

1. I got this at my LHS. I will be taking it back.
2. Don't think my charger is "cheap". It's not high-end, but my LHS guy recommended it, AND he charged the exact battery for me using the same charger before I left. It certainly should not be low-end enough to start blowing up batteries.
3. My LHS guy told me to charge it on current 1A. However, I went by the instructions and charged it on 2A. I KNEW I should have listened to my guy.

This one I will fight however, even if I have to go through OFNA. When things are ID10T errors, I admit it. However, I went exactly per the instructions. What sucks is this happened right during the break in process. Now I need to pull the five cell from the Losi 8ight and hope it works just so I can continue

t-max97

My Feedback: (9)

It was on trickle charge an hour later because it was done charging, you over charged it.

JohnP2

Help me better understand this. It was not on trickle charge for an hour. I checked it about ever 10 minutes and took it out once Isaw it was in trickle mode, so it was not on trickle for more than 10 minutes at the most.

I asked the LHS guy if "the charger will stop charging when it's complete" and he affirmed, stating it would just slow charge and be fine. Even the instructions stated once it reaches its peak, "fast charge" will stop, and trickle charge will begin, indicating the battery is ready for use at any time.

Thus if,
1. Trickle charge indicates charging is complete
2. Once it begins trickle charge you've over-charged it
That makes no sense. I'd think you would get more than 10 minutes of trickle charge before you fry it, wouldn't you? If not, you have to just "guess" and take it out before it goes into trickle mode. Anyway, it will be interesting to see how my LHS reacts for returns. I know the guys fairly well, so we'll see. I've even dontated un-opened parts that I don't need to them, so I hope they give me a break. I don't mind shelling out bucks for replacement parts if i was the cause, but in this instance I followed the instructions.

Thanks!

nitroexpress

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nitroexpress

The Onyx100 seems to limit itself to charge rates of 1A/2A/4A. This is really a inappropriate restriction.

Your battery failed, not because of overcharging, but was fried by the high rate of charge. 2A might be OK for a 2100mah battery, but your pushing it for a 1600mah battery. Silly DuraTrax. Personally, I wouldnever have a DuraTrax product. Had one of their chargers years ago and it had problems. I wouldn't surprise me if the Onyx had an inaccurate voltage cutoff circuit. But without a meter onthe charger, who knows what it is doing.Keep to a 1A charge rate and you should (maybe)be fine. Personally,I'd feel safer with a HobbyWing charger for just a few bucks more.

JohnP2

Yea, I've learned regardless of the instructions, I will stick with the !A for this battery. Anyway, below is a pic of it. I've not had a chance to mess with it today to see if it still works. The flame shot up when I touched the red wires (while it was smoking). Flame shot up over and inch.

Or, should I even mess with it. Don't want to harm the receiver...or myself. ;-)

echthelion

id say its as dead as you can get

nitroexpress

It's too charred to trust. Dump it.

Ttowntoolman

Damn dude, that thing looks smoked! I would agree, the charge rate most likely too high, melted wires, dead short! I usually charge all my hump type reciever packs at half the rate of normal cells. 1600 mah pack gets 0.8 amp just to be safe never had an issue. The last hump pack I purchased new had a note on the package that 1.0 max charge amperage......

Now is your chance to rethink this hump pack thing.........if you choose to purchase a pack with only one lead on it you will need to take you ride apart to charge the hump pack. Unless of coarse you wire in another lead you can access from the outside for charging. I just purchase the pack with two leads and leave one hanging out..... Tower part#LXYZZ0 I am not saying this is the best pack at all, just using it as an example. Yea, that is the latest pack I did purchase.

nitroexpress

No need to remove the receiver battery for charging. Replace the power switch with one that has a charge lead. It's pretty much a standard upgrade.

supertib

charging at 2 amps wont do that...... compressing the battery too much to fit into he battery box will ! my guess is something got pressed together that shouldn't be pressed together...... I have charged small hgump pack higher then 2 amps with no issues...Not that I recommend it, but charging at 2 amps will not result in fire..... something else has mechanically happened to that battery to short it out....

hunt2010

I must say something about Duratrax even though im an AE man, Ive been using Duratrax products for years and had very little problems with their products, they also have great customer service. As for your charging problem, Ive had that same charger wit no issues at all. I do believe you over charged it while it was in trickle by trying to put to much juice in the battery when it was already charged, Its ok to charge at 2.0 amps with a 1700mah batt. for a quicker charge but sucks the life out the battery in the long run. I usally charge at the batt.mah and no higher. Charging your batt, at 1amp or 1.7amp would be best, I would try to get it replaced or trash it cause you fried it ,before you burn your house down and breathing those toxic fumes those batterys give off. Its just part of the hobby, we all did something crazy at one time.

JohnP2

Yea, it was a scene man, when it blew up. I just stood there with failed smile.

I do have a lead coming from the charger I can use to charge the battery (I figured that out the minute I installed it).

The trick is that the hump pack just BARELY fits in the battery casing. No room for wire at all. Neal, you might be onto something, as mentioned, it BARELY fit.-AND I kept an eye on the charge and went per instructions. What alternatives are there if it won't fit?

Thus I rewired everything so that all leads go to the receiver housing, where there is plenty of room. All I do is unclip the receiver case top, and then plug it into my lead coming from the charger.

Of course I've learned now to set it to 1A.

Question: In the event I accidently over-charge (or feel it is over-charged, I'm paranoid now), is there a method to de-charge it? Other than leaving it out in a cold environment?

Thanks!

echthelion

chargers like the one i linked have a discharge function and of course because it has a screen you can see how much mah you put into it

t-max97

My Feedback: (9)

I must have read it wrong I thought you said once it started trickle you restarted the charge again. And no I dont think a 10 minute trickle would hurt it. I have two duratrax onyx chargers that work great and I havent had a problem yet and Ive had one of them for two years.

EDIT- Yeah when you said I plugged it back in i thought you meant back in the charger.

phmaximus

It looks like its been charged over 1c and has been over charged, damm that battery would of been hot...

I allways charge my nimh battery packs with a thermometer and out of the vehicle.

check this I found, I agree with this....

This is a good reminder that even NiMHs can start a fire. A couple of things to keep in mind. Lots of people are using the higher capacity NiMH cells. The way they do this is to use thinner material inside. This makes the cell far less robust than say a Sub-C cell is. They are less tolerant of overcharging, fast charging, and vibration.

Under no circumstances should a NiMH ever be charged at greater than 1C (I'm talking about RX/TX packs) and if you can charge a bit slower, that is better. I typically charge at C/2 (1/2 the rated capacity). I also will cycle the packs down and slow charge at C/10 every once in a while. This will rebalance the cells.

Cells typically let go because they have gotten way out of balance during repeated uses. An occasional discharge and slow charge can help with this.

Fire is a great thing, but not from your battery pack!!

The Mad Modder

Had something like that happen to me once. I was charging a novak mini pack with a Losi mini peak charger. Apparently this particular charger wouldn't stop trickle charging; accidentally left it charging overnight and found a similarly well toasted battery the next morning. It warped the battery box of the truck it was in, too.

cummins driver

My Feedback: (31)

I dont think what happened had anything to do with charging at 2 amps.

I would reccomend not charging receiver batteries at over 1 amp, but regardless, I have charged them at 2 amps before as well with never an issue. If you charger a nickel type battery too fast you will know it because the battery will get hot while charging. Warm is fine, hot is not good.

Your charger will not overcharge the battery. You never need to worry about discharging. If you charge on too high of an amp rating, the battery gets filled much faster and will get hotter than it should, but the charger will still cut off at the voltage it should cut off at. Many times charging on higher amp ratings causes the charger to shut down faster because the voltage spikes faster and then settles back down some when the charger quits charging.

That battery shorted somehow in my opinion. Bare wires touched somewhere or something of that nature IMO.

Oh and one more thing.. You can let a battery trickle charge from now on with no harm. Trickle charge simply maintains the state of charge the battery has once it is done.

Eric

rcacro

I second what Eric said! Charging at 2 amps did not cause the problem. The wires to the battery terminals shorted somewhere. The point where the melting started on the wires is where the short was.

John W.

mattster1971

That sucks John, If the battery was charged based on its requirements I cant imagine you over charged it. I agree with some of the comments above that think it was a short in the pack somewhere. I love my little charger which I use exclusively for the rx packs. It lets me choose on screen the type, number, and then determines automatically the rate of charge, usually 1.2 or less and then off it goes and beeps nonstop when done until I remove it from the charger. I have yet to have any difficulties with it. I would return the pack to the store for an exchange. God does not want you to run that new Truggy John. Sell it now! Just kidding.

nitroexpress

I agree that it could have been a short, but where and what caused it? The batteryonly flamedwhen it was plugged in (to the on/off switch or direct to the receiver?) and this was after the charging was complete.The battery box was closed, so any damage from the charge would have been hidden..Is the point of maximum melt on the batterythe area of the short or just the weakest area when max amps were drawn by a possibly shorted on/off switch?

Can a charger malfunction be ruled out? Maybe the charger didn't really shut down at full charge. It could have damaged the battery wiring (hiddenand enclosed tightly in the battery box) No matter what the brand of charger, I'd always want a display so thatthe actual charger operation can be checked.