Li-on Battery Dilemma

[Madman]

I noticed that one of my 14.8 volt Li-on batteries seems to have lost is power. It was powering a 12 volt bilge fan that I have rigged up on a flat car to blow leaves off of the track. Yesterday, while operating said device, the fan suddenly stopped. I figured that the battery ran out of juice. So I placed it on the charger, but the green light of the charger stayed green, instead of going red for the charging mode. I checked the voltage this morning with a meter, and it read 16.8 volts. Somewhat higher than the batteries original rating. Then I hooked it up to the fan and nothing happened. Only a slight turn of the blades each time I switched on the fan, then nothing. These batteries have the PCB protection circuit board to gaurd against over discharging. Or that's what I thought it was supposed to do.
Can anyone enlighten me here?

 

[Del Tapparo]

Dan - I haven't had any Li-Ion batteries reach end of life yet, so I'm not sure what happens. At 16.8V, the charger thinks the battery is fully charged, and it is. It just may not be able to handle the load anymore. Try running something else with it that doesn't require so much current. Perhaps the fan needs some maintenance?

 

[nicebutdim]

Try something else to test the output, another fan or motor or something similar. They fan may have died.

 

[Gizzy]

Fan seized? Or as it's a 12V fan, maybe the windings have failed.

Check the fan with an ohmmeter.

Try connect a suitable lamp (i.e. from a car) to your battery and leave for an hour or two, then check the voltage again....

 

[Madman]

OK, I drained the battery by hooking up three 12 Volt lamps. It powered them for a day and a half. When the lamps were no longer lit, I took a reading of the voltage being produced by the battery. It read somewhere around 10+ volts. This is where the PCB is supposed to cut power, which it did. I then re-charged the battery overnight. This morning I tried the charged battery on the same bilge fan with the same results as before. It barely turns the fan blades over, then they stop. Could this be a dead Li-On battery?

 

[coyote97]

hi madman,



i agree with the others:

either the fan never worked properly because it takes too much current,

OR the fan got a defect while operating

But running 3 lamps for more than a day (okokok...it depends on WHAT lamps, but even small 2W-lamps are well run by a small accu over 1,5 days...) does NOT point on a defect of the accu.
It seems that it has its capacity and works on "normal" conditions.

so, give the fan a try:
perhaps u have a stationary transformer (an old lgb or whatever), main thing is that you can bring out some voltage up to 12 or 13 Volts.
Fit the cables of the fan on it and give it a testrun.

When the fan doesnt blow, u shouldnt go on the search for an accu-defect......


I fear, that u may have done a construction-fault.
A fan that really blows out leaves and dirt will take quite an amount of current. I think this might be too much for the accu-pac.

an old fan out of a computer wont take much, but it wont blow leaves, either.


Greetings

Frank

 

[Madman]

I placed the battery in question into one of my battery cars. It drove the loco perfectly. I agree that the fan may be asking for too much power in the way of amperage. However, previously, the same battery operated the fan well. Could the fan have done some damage to the battery? The fan is in good working order.