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battery tester

Old 08-21-2008, 08:14 AM
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magnum500
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Default battery tester

lost an airplane today due to a faulty rx battery , there was a volt watch on board it was reading all green . my question is ...
is there a company that makes a good reliable tester ?

R.I.P Cap 580
Old 08-21-2008, 08:26 AM
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fancman
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Default RE: battery tester

ORIGINAL: magnum500

lost an airplane today due to a faulty rx battery , there was a volt watch on board it was reading all green . my question is ...
is there a company that makes a good reliable tester ?

R.I.P Cap 580
I only ever use ESV's to check battery voltage. Such as these:

http://www3.towerhobbies.com/cgi-bin...?&I=LXWW16&P=0

I wouldn't rely on a volt watch.
Old 08-21-2008, 10:26 AM
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Gray Beard
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Default RE: battery tester

I have A couple of volt meters, the one I have in my flight box is an old ACE from Horizon. If you want to spring for the extra bucks Horizon has A meter that is called the DVT, it checks the voltage under load and is also A TACH. Price is 46 bucks though. They also have A very good Variable Load Meter for 40 bucks.
Most the time the volt watch is pretty good, I still always test with A volt meter though before flights but so far other then A battery with A wire short the VW has always been OK as A sight warning for me. The one time I had A bad wire shorting out both the meter and VW said good to go. After the crash the battery was still checking out good until the wire was wiggled like if it was in A plane and under engine vibration then it showed the problem. I have also had A switch go out on me too and then the battery was good.
Just stuff to think about.
Old 08-21-2008, 10:41 AM
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WCB
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Default RE: battery tester

Fancman is right. Check the pack under a realistic load for the type of servos you're using and leave the ESV on there for a few minutes to see if the voltage drops dramatically which is a good indication the battery is going bad. Just because it takes a charge and peaks is no indication that all the cells are ok. Cycle the pack occasionally to make sure it is delivering at least 80% of it's rated capacity. If not, chunk it. Always cycle a new battery. There's nothing more dangerous than a brand new pack. That's about all you can do. I don't think there is anything that is 100% foolproof (except having 2 reciever packs?)
Old 08-21-2008, 03:47 PM
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Default RE: battery tester

I've seen voltwatch show green until you move the sticks then goes to yellow and back to green once the sticks stop moving....
Expanded scale voltmeter for me
Old 08-21-2008, 06:53 PM
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Default RE: battery tester


ORIGINAL: magnum500

lost an airplane today due to a faulty rx battery , there was a volt watch on board it was reading all green . my question is ...
is there a company that makes a good reliable tester ?

R.I.P Cap 580

G'day Mate,
Check these out, http://www.westonuk.co.uk/index_176.htm
I have one in my Katana, they are great.
Old 08-21-2008, 08:18 PM
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magnum500
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Default RE: battery tester

i had a tac/voltmeter from H9 , the tac crapped out so i tossed it , would that test under a load ? thanks to all who have replied , all very good advice .[8D]
Old 08-21-2008, 08:25 PM
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magnum500
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Default RE: battery tester

i have seen that as well . i usually cycle ailerons , tail and elevator at the same time to see if it drops at all , if the volt watch moves at all it does not go up .
Old 08-21-2008, 08:50 PM
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airbusdrvr
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Default RE: battery tester

Futaba make a nice one that checks 4, 5 and 6 cell batts, http://www3.towerhobbies.com/cgi-bin...FUTABA++br2000 . It can also be used to cycle(discharge) a battery pack.
Old 08-22-2008, 11:24 AM
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JohnW
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Default RE: battery tester

For consistency, and accuracy, use a loaded volt meter that places a predefined load on the battery. If the meter doesn't mention loading, or its load size, don't use it. In addition to the reading, check how many mAh your batteries take when charging. Keep notes if you have too. You'll start to see a pattern, i.e., I use ~100mAh per flight; I safely get 5 flights per charge with a loaded voltage of X after the 5th flight. This way, if something is starting to malfunction, you'll notice it right away, i.e. I got my 5 flight voltage after only 3 flights, something is not right.

Moving the sticks around making a control surface move back is not a realistic electrical load (too little load.) This will probably not give a good result when using a non-loaded meter, like a voltwatch.

Two RX packs are not foolproof. They do however reduce the chance of total system failure should one power system malfunction. But it may not protect against all failure modes depending upon the battery you use and the setup employed.
Old 08-24-2008, 05:45 PM
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Jezmo
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Default RE: battery tester

I've had a number fail in the last 25 or 30 yrs and all were checked with a load on them before flight. (In the early days I used an S&O expanded scale voltmeter with a 300 mah load. Later ones were with a Futaba voltmeter with a 1000 mah load.) Each one that failed went open circuit without warning. Most were fairly new and my oldest packs seemed to be the most reliable. (If a pack was going to fail it seemed to do so rather early on in it's life) Certainly the ones made with Sanyo cells faired better. I also cycle my packs and if they show more than a 5% loss from their stated capacity I discard them. Even with these precautions I have been bitten by the battery bug. Redundant packs probably would have saved my planes but I have seen packs go short circuit and in that case nothing would have helped. These days I just use the best batteries I know of (Sanyo) and enjoy. (Yes I still cycle and check with a load capable voltmeter.)
Old 08-24-2008, 06:21 PM
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OldScaleGuy
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Default RE: battery tester

Here you go, this is the one you need.
http://www.rcuniverse.com/market/item.cfm?itemID=427082
Old 08-24-2008, 11:01 PM
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42etus
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Default RE: battery tester

Voltmagic. Absolutly the best there is.

http://www.voltmagic.com/

Paul
Old 08-25-2008, 09:16 AM
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Rodney
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Default RE: battery tester

I have never used the Voltmagic but it appears to be a device very similar to the Voltwatch. IMHO (as a retired EE with many years in the hobby) I believe that the Voltwatch is superior to the loaded voltmeter for most applications although, if used prior to every flight, the loaded voltmeter is nearly as good. The reason is that the Voltwatch (and I would assume the Voltmagic will as well) give you more information. It is using the actual load used in the previous flights so the voltage is quite settled plus when you cycle the sticks you can see if any problems are present due to voltage drop in a switch or wiring or binding servo as, if the lights are cycling or blinking in the yellow region, even momentarily. It is almost as good as having a scope on the battery voltage as it shows up those momentary voltage drops caused by the current surges as when a servo first starts to move. This is especially important if you are using one of the 2.4 GHz systems as they may reboot if you get a voltage drop for just a microsecond or two. Loaded voltmeters do not show up these type of problems which are much more possiable than just a low battery which is also caught by the Voltwatch.

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