Burning Plastic while charging

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Measton
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Burning Plastic while charging

ON two recent occasions I've noticed the smell of what I believe is burning plastic after leaving the charger on overnight. The batteries work fine, I did 25miles yesterday w/o a problem. I think that 1 of my two chargers may have a problem determining when the battery charge is full. It seems to continue to run long after the scooter should be fully charged. The charger is not hot but the lights remain red. The floor of the storage compartment seems warm, I believe the batteries are getting hot and causing the problem possibly because the charger is not shutting off. Has anyone else had such a problem? I'm going to try it again with my other charger to see if it is charger specific.

Thanks

Measton
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Re: Burning Plastic while charging

Well after further reading it sounds like thermal runaway. Next step is to see if my batteries are shot.
New set of questions
1. Ways to prevent thermal runaway? It seems like one could make a thermal cut off switch that would cut off juice to the charger.
2. Does thermal runaway prevent the battery voltage to rise high enough to shut off the charger?
3. If the batteries still function will they be prone to problems riding or charging in the future?

davew
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Re: Burning Plastic while charging

What sort of batteries are you using? Most NiMH and LiIon batteries have thermal protection built in. It's the third wire on the charger that goes to a sensor buried in the pack.

"we must be the change we wish to see in the world"

mf70
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Re: Burning Plastic while charging

Have a look at
http://visforvoltage.org/forum/6763-exploded-my-batteries-my-xb-600

And track the smell down! It won't get better on its own.

Measton
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Re: Burning Plastic while charging

It has the original Emax batteries which I believe were a ?? silicon gell lead acid battery. It looks like the scooter will still run, not sure if the range is decreased or not. I suspect once this sort of thing happens that the risk of it happening again goes up. It wasn't that hot when I charged the scooter. My current plan is creating more ventilation and possibly using a fan, and not charging it overnight, but if anyone else has advice I'm all ears.

sixpax2k9
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Re: Burning Plastic while charging

same advice as to anyone with this problem..... Use a voltmeter to check every battery to make sure all are ok. If you have a 12V charger, charge them individually first, then connect again. check the output of the charger as I have seen chargers increase in voltage for no reason...... I have a 60V charger that charged at 69V (normal), for no reason that I know of it started outputting a Voltage of 72-73V. Thus the 60V pack could never theoretically achieve said voltage so the charger never shut off. If I had not noticed this happening I am sure my batteries would be messed up big time!!!!!

more than likely you have 1 battery that is undercharged, keeping the series pack undercharged. Thus there are 3 or so batteries being severely overcharged because the one battery is so undercharged the "pack" never reaches its cutoff point and stops charging.

Dave ; Tennessee
XB-600.

antiscab
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Re: Burning Plastic while charging

Hi Measton,

+1 thermal runaway.

the original charger for my emax 90s did the same thing, the one time i used it (original batteries were expendable)

id suggest not spending any money on keeping your lead/silicon batteries going.

the original charger is no good for charging lead batteries (no temp compensation) but is good for lithium batteries (when used with a BMS).
i know the new emax frame (which is exactly the same for *all* models) can fit around 28 TS 40AH cells. without modification.
16 cells will give you the same performance (and lighter weight) as what is advertised for the silicon models.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
conversion

PJD
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Re: Burning Plastic while charging

Couple comments,

Regarding sixpaxs comment, 72 to 73 volts (about 2.4 volts per cell) is a normal maximum charge voltage for a 60 volt lead acid pack for moderate to temperatures. It is a bit high for hot weather.

As Matt mentioned, the have been plenty of reports of e-max chargers malfunctioning and badly overcharging and ruining the stock silicone cells - which are very intolerant of overcharging.

Matt, How are you fitting 28 TS 40AH cells in your e-max? are you using the space under the seat?

antiscab
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Re: Burning Plastic while charging

Matt, How are you fitting 28 TS 40AH cells in your e-max? are you using the space under the seat?

I am referring to the current model emax, the frame used for the 90s and 110s.
the battery box is *huge*.
in stock form the space under the seat is approx half that of the original emax sport.

next year a new emax scooter based on a new frame will be released, with an even larger battery box.
This is to facilitate the 190L, with 45 mile range at 60mph (25 x 90AH cells)

Im at the factory in Wuxi, Jiangsu province, China now.
Having a look around the factory, the quality has improved massively since the emax sport debacle (failure rates on all components <0.5%)

its a shame none of their current scooters can do better than 50kmh (real) in stock form.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
conversion

Measton
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Re: Burning Plastic while charging

i haven't checked the batteries yet, but I'm leaning more toward the charger as I was able to charge with the other charger and it shut off. I'll try some of the diagnostics above. Thanks.

Measton
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Re: Burning Plastic while charging

pulled the lid
4 batteries bulging pretty well
The other 4 look OK. I think there are two parallel strings and one fried.
Still haven't checked the voltage.
I'm mostly using it to run to the hardware store a couple miles a way and it still has plenty of juice for that so I'll run these until it won't make that run and then I'll replace them all. I suspect they are all damaged.

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