Paralell battery operation and Loaded VOM questions  
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All Forums >> Radios, Batteries, Clubhouse and more >> Batteries & Chargers >> Paralell battery operation and Loaded VOM questions
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Paralell battery operation and Loaded VOM questions - 4/17/2002 5:54:05 AM   
dan__olson


 

Posts: 28
Joined: 3/30/2002
From: Fort Dodge, IA, USA
Status: offline 		I'm looking to run a backup battery pack in my airplane, but I have a question. Do I need to run a diode on one wire of each battery lead. What I am concerned about is one battery shorting and the other battery dumping it's power into that battery instead of the reciever. Maybe that's not the case however. Another question I have is, how much voltage drop is expected with a load of 500 milliamps on a battery pack? I built an esv with a mutlimeter and a set of light bulbs for a load (thanks Red ), and I am seeing like .6 volts drop with it attached. Is that about normal? What would be minimum flying voltage with that setup? The same 4.8 volts as any other load (I assume this, but want to make sure). Thanks for any help you can provide.
       Post #: 1

Paralell battery operation and Loaded VOM questions - 4/18/2002 1:09:47 AM   
Jazzy



Posts: 1106
Joined: 1/8/2002
From: Erie, PA, USA
Status: offline 		Diode... How would you charge the packs with a diode in the line?
An inline fuse might be in order if you're that worried about it. What size packs are we talking about?
If you have a short in a pack during flight you might see smoke or flames coming from your airplane as it goes down.
I built a digital VM out of a simple meter purchased at a local electrical supply house, one 10 ohm 1 Watt resistor, and a double throw switch. With the switch I can check the batt with or w/out load. The resistor puts about a 330ma load on the pack with a voltage drop of around 0.2V. Six tenths of a volt sounds a bit much to me. Check the resistance of your bulb-string with a meter to make sure of the load.

Jeff

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Aww $#!^.... I left the )@#& transmitter at home!

(in reply to dan__olson)
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Paralell battery operation and Loaded VOM questions - 4/18/2002 2:17:34 AM   
Red Scholefield



Posts: 5042
Joined: 12/8/2001
From: Newberry, FL, USA
Status: offline 		For detailed information on parallel operation see the article at the Battery Clinic. Don't worry about a cell shorting in a pack when you are flying. A charged cell cannot short instantly and cause a problem. It has to be in the discharged state before the short can be established - unless it is from an external source.

Your .6 volt drop is too high. Something is wrong in the circuit or you are using very fine wire.

_____________________________

Red S.
AMA 951 Leader Member
Disclaimer: What I have written here are my thoughts and in no manner shape or form reflect the views of RCU

(in reply to dan__olson)
       Post #: 3

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All Forums >> Radios, Batteries, Clubhouse and more >> Batteries & Chargers >> Paralell battery operation and Loaded VOM questions
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