Oops - Futaba 6ex 2.4 Ghz

[BB]

Advice needed forumnites.

 

Went flying yesturday.  Came home and packed everything away as usual ! NOT.  Left my TX switched on !  There were a few spots of rain at the patch, and when I got home I took it out of its case.  I must have switched it on to check it, but forgot to turn it off !

 

When I checked it this morning, there was no reading on the display.  Knowing that the failsafe would have kicked in I wasn't too worried.  However, on a full charge it normaly shows 11.4 v. 

 

I've connected to the normal Futaba charger (150 Mah) but after 7 hours its still only showing 10.4 v's.

 

The battery is an Overlander 2000 Nimah Mha.

 

Question for you guys is should I recondition the battery.  I have a Graupner 16  charger.

 

BB

 

P.S. the weather is kak in Essex.  So no flying today.

[birdy]

well my 6ex's charger goes at 70ma, therefore, assuming you have the same charger, that would men that you have only put in 490mah, a quarter of the batteries' capacity. I would leave it on charge for abit longer if I were you, but that's assuming you completely depleted the battery. 

If the battery was fully charged before you went, then you should be able to see how much battery was used (look in the instructoins for current use), by working out rougly how long you left it.

 

hope this helps and your batteries are OK,

 

birdy 

[Tim Mackey]

He says his charger is 150mah, so at that rate 7 hrs will pump in around 1A, about half the capacity.

Leave it charging another 7 hours and see how it goes, if in doubt, get one of those nice Vapex Instants / Sanyo Eneloops and replace it for peace of mind.

It should be OK actually, as nimhs are far more tolerant of deep discharge than lipo.

[birdy]

Ooops, should have read it more carefully...

[Peter Beeney]

 

    Without wishing to differ or detract from Timbo’s and Birdy’s posts, may I offer a slightly different perspective? This how I might see this situation.    

      The formula for charging nickel batteries is thus:

    C + 50% ÷ charge rate. This will give you the charging time in hours. So in this case;

    2000mAh + 1000mAh = 3000mAh ÷ 150mA = 20 hours.

    Having said that, the voltage usually rises very quickly on these types, that’s why an open circuit voltage is a useless indicator of the state of charge. It may be possible that the Futaba charger was thrown off course a bit by the higher internal impedance of the cells when they are flat, and has in fact hardly charged the pack at all! I’ve seen it happen!
    If your Graupner charger gives you a readout of what you put in, in mAh, then that would be a better idea. I presume it’s a fast charger?, in which case I’d use something like a 1 amp rate. But even the the best of chargers can sometimes get thrown by deeply discharged packs, I’ve seen this happen, too.
    If the Graupner has a discharge facility, discharge the pack, to find out what you actually did put in, theoretically 150mAh × 7 = 1050mAh, then recharge, making sure that you replace at least 2000mAh. You can’t get out what you don’t put in.

    At some point, when you’ve time and it’s fully charged, give it a discharge to make sure that it has a reasonable capacity. Like wot I’ve been saying for years. Perhaps it’s not quite so important on your tx, it’s highly likely that’s got a low volt alarm, but certainly on your rx pack.

    Hope this makes sense.            PB                                                                                           

[BB]

Thanks for the advice sirs.  The charger has been connected since this morning and the battery is now fully charged.

 

I wasn't worried about a deep discharge state as the 6ex has a built in low voltage failsafe that kicked in.

 

Though at some stage in the near future I may cycle the battery anyway.  Just to make sure its operating at best capacity.

 

BB