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Old 11-18-2011, 04:24 PM
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gphil
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Default Batteries

I was wondering just how long the batteries hold a charge in the radio trans and in the planes receiver. I try to fly each weekend and have been charging the units overnight on Friday. Is this necessary or will they hold a charg e longer than that. Last week my trainner did not come so I just practiced taxing so little or now use on the batts. However it is getting real cool in the nights here and that is hard on a battery. Next question is just what type lower cost volt ohm meter would work on checking the above mentioned? I would just hate to lose a plane because of a dead radio or worse. Thanks and will be looking at the site. gphil
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Old 11-18-2011, 04:34 PM
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Default RE: Batteries

Nickel metal hydride (NiMh) batteries can self-discharge as much as 1% per day. So 30 days after they are charged they could be discharged by 30 percent. NiCd is not as bad. Lithium batteries hardly self discharge at all. Charge in November, fly the next spring.

Harbor Freight sells their multi-meters (to check volts, current, resistance, etc) for $1.99 most every day. that particular item is almost always on special price. You need to put some "load" on the battery to get a better reading.
So I solder a resistor in parallel to the meter. You could also solder in a small light bulb (like a automotive tail light bulb). If you don't want to make something yourself, then get a "loaded voltmeter" from the hobby shop.

Something like this is fine: http://www3.towerhobbies.com/cgi-bin...?&I=LXWDZ5&P=7 for $8.99
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Old 11-18-2011, 05:23 PM
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gphil
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Default RE: Batteries

Thank you much for the information.    I have muddled things out all my life trying not to seem inept but going to ask questions from now on regardless.   Some may be stupid to some but learning for me.   Thanks once more.   Being new to this forum, I hate to ask questions that have been asked a thousand times that is  pesty to some.  Is there a dialog box one can type in and maybe get a good answer sooner?  Here again it may be in plain sight but so far I haven't seen it.   Apologize for the long post here moderator.  gphil
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Old 11-18-2011, 06:06 PM
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Edwin
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Default RE: Batteries

You should have a ESV, Expanded Scale Voltmeter. This meter will put about 250ma to 300ma load on your battery. That will give you a better check of your battery. A loaded battery will read different than an unloaded battery. I like to check my batteries before and after each flight. This gives me an idea how much is being used, and if you see more current drain than normal, a heads up on a pending problem.
Edwin
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Just ask your question and dont worry about what others think. Theres plenty of people here to help.
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Old 11-19-2011, 05:17 AM
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Default RE: Batteries

G'day

Lately I have been using Sanyo Eneloop batteries in my receiver packs and even in some transmitters. Here in Australia they are available made up into 4 and 5 cell receiver packs in various sizes (800 mAh AAA cells and 2000 mAh AA cells) and shapes (flat, square etc) and as 6 and 8 cell transmitter packs with the correct connectors for JR/Spektrum, Hitec and Futaba equipment. The big advantage of the Eneloop cells is their extremely low self discharge rate. Even after three years storage, an Eneloop will still hold 75% of its original charge.

They also come fully charged and can be used immediately without charging though a couple of cycles gets them fully working to their maximum capacity.

More info is available at sanyo.com/eneloop

If there is a downside to the Eneloop it is that they are not suitable for fast charging and can be damaged by overcharging but I have found that the chargers supplied with my various radios charge them perfectly. I also use a Swallow charger to charge them at 200mAh which gives a thorough charge but slowly and does not overcharge them.

I am sure someone in the US is making them into receiver and transmitter packs. Our local importer does so if you get stuck, they are widely available here in Australia.

Mike in Oz

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Old 11-19-2011, 06:53 AM
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Default RE: Batteries

Batteries Plus here in Jackson TN sells them and their tech shop can build any configuration you desire you do have to supply the correct plug. I would bet that allmost all the Batteries Plus can do the same. The Eneloop is basically a NiMh with upgraded chemestry. Mine stay charged for months, I use 4.8 volt 2700 Mah and love them.

Gary
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Old 11-19-2011, 07:11 AM
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Default RE: Batteries

My Eneloop transmitter pack went bad in 11 months. I really tried to follow everything i was told. The battery company told me i had to hold the battery and if it got to hot to stop the charge. OK, who is going to stand there with a 2000ma pack and charge it slow and hold it in your hand all night to see if it gets hot. $50 bucks down the drain. I never charged it fast and used a peck detector charger at only 600ma. I was told I could charge from 120ma to 1amp. Dennis
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Old 11-19-2011, 07:15 AM
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Default RE: Batteries

Trying to avoid the previous night charging chores has been has been like the search for Shangrila of most modelers since the begining of RC flight.

Yes there are methods and fast chargers, cigarette lighter adapters for you car (charging on the drive to the field) as well as new battery technology But and this is a big 'But' you would do well as a new flyer to delvelop the habit right now of always doing slow overnight charges of all your batterys before each outing everytime.

This also has the tremendous advantage of allowing you to do a careful preflight of your airplane while you are doing the choirs.

Many airplanes are lost on early flights simply because they do not understand good charging habits or are simply in to big of a hurry.

I agree with Edwin do not be embarased to ask questions, that is the intelligent thing to do.

John
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Old 11-19-2011, 07:33 AM
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Default RE: Batteries

Those that do the slow over night charge on NiCad or NiMh are usually rewarded with a much longer battery life (more charge/discharge cycles) than those fast charge. While fast charge is convenient for those impatient ones, it is always hard on the batteries. Eneloops should not be fast charged ever. You will find that the Eneloops will provide the most reliable and long term life than any of the other batteries for use in transmitters. They hold a charge as well as LiPo's and will not be destroyed if you discharge them to deeply.
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Old 11-19-2011, 08:02 AM
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Default RE: Batteries

Hi!
all NiMH batteries should be slow charged! That means chargin at a rate of 0,1C for 14-20 hours! In your case 200mAh for 14-20 hours using a simple wall charger
Charging a 2000mAh pack at 600mAh using a peak charger (Which isn't optimal for charging a NiMH pack because they all false peakt) is asking for trouble!
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Old 11-19-2011, 11:27 AM
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That proved to be true, but following the instructions I split the difference at 600ma. I was also told that the wall chargers can over charge as well, so it seems to me that there is a no win situation. I'll use a Life from now on. In the past I had a JR 10X and it 15 years I only had to replace the battery once. Dennis
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Old 11-19-2011, 02:42 PM
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Default RE: Batteries

That's good advice above.I used to do a rushed charge session at one amp the night before flying with a swallow acdc charger.I use eneloop five cell 6 volt packs and in about two hours i could charge the tx(yes!),two flight packs,two glo sticks and both of my 7.4 volt rotostart batteries which i thought was good going over a beer or two.Now i do the glo sticks and starter battery during the week if they need it and the tx saturday arvo.Overnight charge for the rx pack then unplug sunday morning before going to the field.At .01 of an amp it takes a lot longer but the beer seems to taste better
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