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Old Apr 21, 2012, 08:52 PM
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Jim Frahm's Avatar
USA, WA, Spokane
Joined Nov 2003
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Hobbico Volt Watch 2 shorting issues

Hello All!

I'm not sure if this is the best place for this but since I'm a glider pilot I figured this is a good start.

I've been using the Volt Watch 2 on-board battery monitors for years without any issues. Last year a friend of mine said he lost power to his glider due to a volt watch shorting out and draining his RX battery. I decided to check the 6 I had in use and I found 3 of them that had the potential to short if the wires were moved or bumped in the right, or wrong position depending on how you look at it. I removed the clear shrink wrap and ID plate and then de-soldered the leads. To prevent a possible short I added liquid tape after installing a new set of leads. I also checked the voltage needed to light each LED and added a label to identify the voltage at each one. See photos.

Anyway, I wanted to get the word out to anyone using these monitors and ask that you check yours before this $12 item destroys your $2000 plane.

Happy flying!

Jim
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Old Apr 21, 2012, 09:04 PM
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United States, CA, Torrance
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Strong work Jim!
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Old Apr 21, 2012, 10:48 PM
Thanks CB, WD x2, T, DC
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United States, OR, Silverton
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Sano
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Old Apr 21, 2012, 11:19 PM
Sink Stinks
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Orange County, CA
Joined Aug 2004
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I never use things like for this exact reason. One more thing to fail. Especially since it is not required for flight in the first place.
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Old Apr 21, 2012, 11:45 PM
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Joined Jul 2007
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Jim speaks the truth...I was the one who lost a brand new 4.0 spread tow Xplorer...68 oz...X tail due to this issue. That ship was perfect and setup beautifully. I was pounding the competition with that beauty and its all a pile of carbon shards now.

Voltwatch had little to say on the topic. The product should not be in your ships unless its seriously modified. Just grab it by the leads next to the board and gently squeeze - nothing crazy but ill bet your shorts...now consider contest landings bumps and launches and ask yourself how safe is this product.
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Old Apr 22, 2012, 10:39 PM
Which way is it going now
mstone's Avatar
Australia, SA, Golden Grove
Joined Mar 2003
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The Hextronics unit, also sold under other names, has a similar problem and has destroyed at least one plane that I know of.
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Old Apr 22, 2012, 10:55 PM
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I have decided that the while convenient to be able to look at blinky green yellow and red lights I cant see it from the air so why does it need to be on the plane? what is really adding vlaue here when I can plug it into the plane between flights and check on the ground if I really need to...so I tore them all out and chucked them in the trash. I typically find that in an hour an enloope pack will discharge about 500-600 Mah out of the available 1950 or so. based ont hat I charge every 1.25 hours and I am well within the window. If I want to get paranoid I can wire up something for an inline check and test it on the gorund. One less point of failure.

The troubling point wiht these products is that the pole locations of these leads could have easily been located further apart and resolved the problem...
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Old Apr 23, 2012, 08:24 PM
Detail Freak
target's Avatar
Harbor City, CA
Joined Oct 2003
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I saw one of those things smoke in a buddies plane (on the ground).
I will never use one, instead, I will plug in (a loaded ESV) between flights. I feel that is a safer option.

Glad you posted this, Jim. Its a good heads up as I know that some people won't fly a plane without one of them in it.

R,
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Old Apr 23, 2012, 08:46 PM
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Yorba Linda, Ca.
Joined Oct 2003
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Yeap....

Quote:
Originally Posted by target View Post
I saw one of those things smoke in a buddies plane (on the ground).
I will never use one, instead, I will plug in (a loaded ESV) between flights. I feel that is a safer option.

Glad you posted this, Jim. Its a good heads up as I know that some people won't fly a plane without one of them in it.

R,
Target
Great thread.
I agree, I have had more than one with suspect wiring. I stopped using them years ago.
Checking with a loaded volt meter is one way of knowing how much juice you have left in the batteries.
I prefer charging between rounds with a lead acid battery as a power source and a good read out charger. This method tells you how much you put back in and a very good way to learn the discharge of your batteries under fire.

Less is sometimes more.
I suppose those on board voltmeters have a place, I just do not favor them.

Alan
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Old Apr 25, 2012, 01:38 AM
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You know something, I also find that the plate with the markings which is heat shrunk very tightly to the board is bare aluminum on the underside...about 1 mm above the 2 contacts which are already to close to each other.
The manufacture probably doesn't know aluminum is a very good conductor
Pretty scary!

Chris
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Old Apr 25, 2012, 03:10 AM
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SkellefteŚ, Sweden
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I discovered Volt Magic, not so long ago. Much, much better, with useful features. Check out voltmagic.com

/Ville
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Old Apr 25, 2012, 09:13 AM
Detail Freak
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Harbor City, CA
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That still has the same design with the wires going into the board right next to each other....

R,
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Old Apr 25, 2012, 10:16 AM
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Quote:
Originally Posted by liukku View Post
I discovered Volt Magic, not so long ago. Much, much better, with useful features. Check out voltmagic.com

/Ville
I had some of those as well - Target is right same design flaw - grab the leads by the board squeeze and then put your fingers on ice...
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Old Apr 25, 2012, 10:40 AM
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Norway
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Quote:
Originally Posted by webbsolution View Post
I had some of those as well - Target is right same design flaw - grab the leads by the board squeeze and then put your fingers on ice...
I donít know, to me the VoltMagic seems much better.
The problem with the one in the first post is that the wires are simply soldered onto the board without any stress relief (or whatever itís called) to avoid movement of the wire at the solder point. Doesnít need many time of moving back and forth before a wire breaks at the solder point.
On the VoltMagic the cable enters at the back of the PCB, looped through a tight slot, before itís soldered onto the front of the PCB. This seems firm enough to avoid any movement of the wires at the breakage point.
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Old Apr 25, 2012, 11:28 AM
mostly gliders
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SkellefteŚ, Sweden
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Quote:
Originally Posted by webbsolution View Post
I had some of those as well - Target is right same design flaw - grab the leads by the board squeeze and then put your fingers on ice...
I use to improve strain relief with contact adhesive.
Our electronic gadgets are not designed for excessive use of force by pushing and squeezing the stuff, but of course they should withstand normal but careful handling.

/Ville
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