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Old Mar 20, 2012, 02:13 PM
grfcon is offline
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chronic in training
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Help!

help left my transmitter on all night nimh 8 cell pack


I think the pack is 1600 mah capacity.

how many cycles at .1 amp charge and .5 amp discharge to condition?

how long will a charge cycle take?
I have heard that trickle charge is best to recondition the pack... but some guys
say you have to charge at a higher rate otherwise the charger (turnigy accucel 6)
wont' detect the proper cutoff voltage. is this true?

at what point do I toss the battery pack and get a new one 80% capacity?

thanks,

Gary
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Old Mar 20, 2012, 02:23 PM
mrforsyth is offline
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My advice - Plug your transmitter into the wall charger that came with the transmitter and let it charge for two or three days and all will be right with your world. You can perform a capacity check if you so desire but this is not entirely necessary, in my experience.

Mark
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Old Mar 20, 2012, 03:56 PM
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Like Mark said, don't sweat it. You just found out the advantage of using mimh instead of lipos in your transmitter. Just plug in the wall charger, though I don't thing you need more than 24 hours,and you'll be fine. If you have any doubts, Follow these steps. Plug in the wall charger before you go to bed. Unplug it the next night before you go to bed and let it sit overnight. Then turn on the Tx and leave it on to see how long you can fly before you get to the low voltage alarm.

Joe
Old Mar 20, 2012, 04:27 PM
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Forming charge is 1/10C > that's 160mA for that pack. Anything from 100-200 will be OK.
The AC-6 will not terminate reliably, if at all, at that level.

As the guys said:
1. Be glad you don't use lipo
2. If you have a wall wart (like 100mA) do the division. 1600/100=16 hours + 50% for waste charge to charge fully.
Whatever yours is substitute that output.

It is possible to reverse a cell in a pack by doing something like that. It can ruin the whole pack. Not likely but possible. You'll be able to tell by how it works after charging.
If you killed it, get a Sony Eneloop 2000mA pack, a significant upgrade.
You get a new pack when you don't trust it or are unhappy with the performance. That determination is pretty individual.

If you are good at cobbling things together you can yank the pack, make an adapter, then cycle the pack with the AC-6; I'd use 0.3A d/c and 0.5A charge.
But, that's a pain, easiest to do a slow charge.

Do some reading here to get educated:
Technical Tips for NiCd and NiMH Battery Pack Users
Last edited by flydiver; Mar 20, 2012 at 04:57 PM.
Old Mar 20, 2012, 04:47 PM
Alan Hahn is offline
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Quote:
Originally Posted by JoeSantora View Post
Like Mark said, don't sweat it. You just found out the advantage of using mimh instead of lipos in your transmitter. Just plug in the wall charger, though I don't thing you need more than 24 hours,and you'll be fine. If you have any doubts, Follow these steps. Plug in the wall charger before you go to bed. Unplug it the next night before you go to bed and let it sit overnight. Then turn on the Tx and leave it on to see how long you can fly before you get to the low voltage alarm.

Joe
Yes, the OP should congratulate himself for a wise choice!

If there ever was a killer application for the low-discharge NiMH cell, it was in the role of a transmitter pack.
Old Mar 20, 2012, 10:46 PM
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wait.. it gets better


thanks for the suggestions and the links btw. so I am also cycling a fairly new
pack.. 8 cell sanyo 1650 mah nimh.. and set the low voltage incorrectly.. I thought the charger took a per cell setting ( I had heard .9 volts/cell) and I set it there instead of at 7.2 volts for drain voltage cutoff. next thing I know I see my new pack down to 4. volts!! so took it off reset the chargers correctly and am now cycling two packs at .1 amp charge and .5 amp discharge. I'll let you know how it turns out!
Old Mar 21, 2012, 10:32 AM
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They'll be fine. Those aren't lipos.

mw (Captain Obvious)
Old Mar 21, 2012, 02:32 PM
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Welcome to the real world !!

I agree also - LiPo's are not in my opinion a good Tx power pack. NiMH is much more tolerant.

There's no need to go Enerloop actually as most NiMH over counter are low self discharge nowadays ... I have 2300mAh Grundig NiMH over counter cells in my Tx ... I travel a lot and Tx is only charged when I'm home. I can return home after a trip ... Tx not charged since last home ... and it's fine to go flying.

I also have three forms of charging ............. Futaba M Series old 1980's charger at 50mA that can stay connected indefinitely ..... a Prolux Auto detect charger that charges up to 1A depending on cells state and reverts to 100mA trickle when auto detect shuts of fast charge .... iMax B6 that I have leads to fit Tx and I set to 0.5A for charging at field, (which I only did once after doing same as you - left Tx on all night !! and next day wanted to fly ... so I plugged into car ciggy socket and charged radio on way to flight site !)
Old Mar 21, 2012, 03:31 PM
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Quote:
Originally Posted by grfcon View Post
... some guys say you have to charge at a higher rate otherwise the charger (turnigy accucel 6) wont' detect the proper cutoff voltage. is this true? ...
If you're using a peak-detect charger then they're right: If the charge current is set too low, the charger may not detect the battery's peak. But, if you charge at 1/10C or less, that doesn't really matter because you won't harm the pack by continuing the charge after it's full. That's why mosts posts are recommending the wall-wart simple type of charger that'll take 16 hours or so to charge the pack.
Old Mar 21, 2012, 04:08 PM
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I think most will advise the wall charger not because of its safe rate - but because it's the simplest way to go !

But of course you have to have to be careful of getting safe rated charger .... I've seen chargers offered at too high a rate ... ie 2A ... 3A ...

If you were to connect a 3A charger to a Tx socket - I would be afraid of the Tx wiring frying ! let alone the pack being subjected to too high a rate.

It's generally accepted that ~700mA up to 1A is about max for a Tx socket.
Old Mar 22, 2012, 08:06 AM
The Tug is offline
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If it were a lipo would it have been the fault of the battery or the user?Welcome to the real world.


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