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Old 07-29-2004, 02:03 PM   #1
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Default Use of Voltmeter

1. My charger has a place to pug in the leeds from a Voltmeter. When I first start charging a 6 cell 3000/3300 mah battery I get a read out in the 7s when the battery has finished charging I get a reading in the high 9s. Do either of these number tell me anything? So far the only use I have found is to tell me roughly how charged the Battery is at the time. Does a particular battery's higher voltage at peak mean anything?
It is my understanding that when the number stops going up the battery is fully charged.

2. I would like to meausre amps but I am not sure how to do it when the battery is charged without heating up an blowing up my voltmeter.

3. I tired to measure voltage while discharging, by hooking my battery up to a 10 bulb battery discharger. I was getting voltage numbers under 6 for the pack and under 1 for individual cells.

4. Is there any way of using a voltmeter to test for the numbers you most frequently see quoted on gp3300 cells, average discharge at 30 amps.
i.e. 1.16, 1.17 etc.

5. Can you use the voltmeter to determine the relative strength of several different batterys when it comes to average amps.

DO yo use a voltmeter ? If so what do you use it for.
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Old 07-29-2004, 02:37 PM   #2
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2. I would like to meausre amps but I am not sure how to do it when the battery is charged without heating up an blowing up my voltmeter
If you want to measure how many amps you battery is taking from the charger, run it inline and on the Amp setting on the Multimeter. If you want to measure from the batteries to the motor, just run it inline and rev, the motor will turn and it will give you an amp reading.

Be careful if it is fused though because Hot winds will pull over 10 amps at full throttle, even with no load.

I use one to check motor efficency, and whether my batteries are charged or not, also whether I need to turn the engine over on the car because the 12 volt is going flat. Jonathan
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Old 07-29-2004, 03:29 PM   #3
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You can also measure the voltage of individual cells by touching the probes to the battery terminals, however this will only work if the pack is "open" and not shrunk wrapped. You can see peak v per cell and also see voltage as the pack is put under load through a discharger.
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Old 07-29-2004, 06:19 PM   #4
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Really good batteries will peak around 9.0 volts or a little more. As th e IR goes up, the peak voltage will also go up. My old NICADS peak at 10 or so volts. My best packs peak at 9.15 or something like that.

I wouldn't mess with amps. A series meter works, but also changes the load. Unless your meter is a good one, it will just pop the fuse anyhow. A hall effect inductive pick up is much better for amps.

I use a volt meter a lot.

To test average volts like the stickers on your matched batteries, you need some more advanced equipment.

Have fun, a volt meter is a great tool.
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