Digital voltmeter
 

Hi guys,

After all the horror stories about drained batteries on this website and at the field I want to buy me some protection..

I might buy this http://www.horizonhobby.com/Shop/ByC...?ProdID=HAN111 it's a Digital Voltmeter/Tachometer. Do you recommend this? I heard it's a little less accurate... but hey, it's 2 in one right! :-) The tach would be kinda neat to have for the future...

And how do I measure if it's safe to fly or not... how much voltage should it indicate when it's fully charged and when it's not safe to fly?

I have a JR Quattro, 4 cell batteray 600 mah.

RE: Digital voltmeter
 

The 2 in 1 meter is about the same price as buying the voltmeter and tach separately, but it does result in space saving in your field box. I don't think you will go wrong with the combo.

DaveB

RE: Digital voltmeter
 

The meter does put a load on the batterys so you get a more accurate reading vs. get a high floating voltage reading and thats what you want. If you don't mind seperate tach and meter you could also look at the Hobbico meter. Its similiar and tells you if its safe to fly or if its time to recharge. Check out the link below to look at it. I also use a Super Test battery tester now and then to find out exactly how good the batterys are doing.
http://www2.towerhobbies.com/cgi-bin...&I=LXWW16&P=ML
http://www.californiasailplanes.com/supertest.html[8D]

RE: Digital voltmeter
 

I've had a DVT for about 2 years and still works great. I recommend it. It does put a load on the battery. Save space also. Just have to keep up with the wire for the voltage checking, but no big deal.

RE: Digital voltmeter
 

I have had mine for over 2 years now and recommend it as well. I check the voltage on my planes between every flight and have yet to have a problem.

RE: Digital voltmeter
 

I've got the same DVT and it's great. When you are checking your batteries you want a meter that puts a load on the batteries. The batteries we use are a strange in ways. Using a standard voltmeter (without a load) it's possible that a battery can read good, but when a load is put on it (actually using it in flight) the voltage can drop to almost nothing and you lose your plane. The DVT puts a 300 Mah load on the battery pack it's checking. This is pretty close the normal usage load that will be on the pack during flight, and is enough to cause bad cells to drop to low voltage under a load. Very very good insurance.

As for how low. The actual lowest voltage is 4.8v. Each cell in a pack has a minimum voltage of 1.2v, and 4 cells times 1.2v equals 4.8v. (FYI, max voltage per cell is 1.5v. for a total pack voltage of 6v) The receiver is designed to operate from 4.8v and up. Below 4.8v and the receiver won't work properly. My rule of thumb when I fly is 4.9v checked with a load. Below that and I wouldn't fly. It's not worth risking your plane just to get a couple more minutes of flight in, IMHO. Better to go home, recharge, and fly again another day. I use 1600 MaH NiMH packs and I usually get 5-8 10-15 minute flights on a flying day. Plenty of stick time for me. :D ;)

Hope this helps

Ken

RE: Digital voltmeter
 

Thanks guys! Very good info!

RE: Digital voltmeter
 

That one is a keeper -- it works very well.