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Old May 18, 2001, 06:13 AM
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NY
Joined Dec 2000
235 Posts
Transmitter bat. charge ?

If I replace the nicad's in my transmitter with Nmhi can I still use the wall charger that came with the radio?
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Old May 18, 2001, 09:28 AM
AMA 697691
Rochester, NY, USA
Joined Aug 2000
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You bet! The stock wall chargers are typically a slow charge or C/10 rate.
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Old May 18, 2001, 09:59 AM
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Rhode Island
Joined Oct 2000
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Keep in mind, though, that if you replace a 600mah pack with a 1500mah pack, you've effectively converted the charger from a C/10 to a C/25 and your 15 hour charge times will now take 37 1/2 hours.
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Old May 19, 2001, 03:19 PM
Senior Member
Dallas, Texas, USA
Joined Feb 2000
363 Posts
Also, although not that critical since most of us charge our transmitters right before we fly - NiMh's have a shorter shelf life on a charge. Basically they self discharge about twice as fast as Nicad's. So don't charge your transmitter on Monday, and then go flying on Saturday or the following week and expect them to be "fully charged". However, when you charge them before you fly, you will get significantly longer run times on your transmitter. ie, NiMh 1700's will run your transmitter practically all day.

Cash
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Old May 19, 2001, 07:48 PM
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Austin, Texas USA
Joined Mar 2001
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Yes, NIMH will self discharge faster than nicads. But even if they are only half full by Saturday, you will still have 800 mah of juice!
Oh boy, what have I started. This could go on for weeks...

Personally, I use Sanyo 1600 NIMH cells in a brick pack in my Hitec transmitters. They are rated 1600 mah and I use them for Speed 400 motor packs, also, where I charge them in half an hour at around 3 amps.
We sell these brick style packs for $24 on Sale right now, and they are very high quality.
Traditionally, NIMH do have a high discharge rate. But I have found these cells to hold their charge very, very well. I will peak my motor pack at the field after charging it several days previously, and it only takes a minute or so. NIMH used to have a daily 3% self discharge rate. But these Sanyo cells seem to be much lower.
My Hitec TX charger is 55 mah. So a 30 hour charge from the wall is required for the NIMH packs. But you can always fast charge them using your peak charger.

Shawn
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Old May 21, 2001, 01:39 AM
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Auckland New Zealand
Joined Mar 2001
386 Posts
As posted above, you can use the wall charger, but it is a long slow process if the batteries are well down. However the greater capacity means you probably only ever half discharge them, & because they don't suffer from memory effect you can put them back on charge from any state.
NiMH tend to prefer to be charged at C rather than C/10, so in theory you should charge on your fast charger at 1.6 amps for 1600 cells. But your transmitter may have a 1 amp diode in series with the charge line, so it is safer to charge at 0.5 - 0.8 amps, a good compromise between speed & safety. In theory a flat 1600 pack would be fully charged in 2 hours at .8 amps.

Make up an adaptor from your fast charger to the transmitter socket & make sure you get the polarity right before you connect.
Check the polarity from you wall chargers lead.
I think Futaba have + in the middle of the socket, while JR have - in the middle. not sure about Hitech.

[This message has been edited by Keithw (edited 05-21-2001).]
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Old May 21, 2001, 03:56 AM
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United States, CA, Bear Valley Springs
Joined Feb 2000
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I got a male Tx battery plug from Hitec and made an adapter with it with Sermos on the other end. Now I just plug the adapter directly into the Tx pack and hook up to the charger. Seein's how I seem to have a penchant for accidentally leaving my Tx on, it's saved a few trips already by being able to fast charge my Tx.

mw
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