How can I test the output of a 12v battery charger?
I have 4 chargers and all of them test to “0” volts with VTM on the leads----no battery connected.
Connect to the battery and take a reading with a multimeter
What did battery read before connecting charger to outlet
What does it read now plugged in
The difference is your output
Should help you
I got a multimeter at Harbor Freight reasonable price that’s nice to check AA and AAA batteries found in a drawer
1- battery reads 11.8
2- battery + charger reads 11.8
3 - no voltage read on charger alone.
4- no voltage read on 4 different chargers w/o battery
With “main” charger the battery still dead’s 11.8 after 24 hrs.
I have another charger on it now. Will see what happens tomorrow.
Hook your battery charger to your batterie. Pinch your voltmeter in the clamps. With your charger unplugged. Get your reading then plug your battery charger in. Should be an increase.
Most newer battery chargers are JUNK, right out of the box! They operate off of a cheesy circuit board, instead of the older wrapped wire system. Just the difference in weight tells the story.
That being said, an easy test would be to turn the charger on, set it to the 2 amp setting. Test the leads with a multi-meter, as previously suggested. You should be reading 2 amps. Try the same on the 10 amp setting, you should read 10 amps. Quite simple.
Dr, sure you have power at outlet?
most newer chargers will not send an output charge if it doesn’t detect some voltage, keeps from blowing up an internal shorted battery. With teh charger hooked up, it should show an increase in voltage from not having the charger connected. Sometimes you have to trick them with another battery and jumper cables to get them to start charging. If you have a smart charger, your battery voltage may not be low enough for it to decide to start charging
There doesn’t seem a good/easy way to check.
The newer digital multimeters can measure down to 1/100 volt. Using one of these allows you to tell the state of a charge. 11.65 volts means the battery is DEAD 0% charge. 12.45 means 70% charged and 12.75 is a 100% charge. Some newer chargers will not “start charging” a stone-dead battery. I have used a motorcycle battery connected to the dead one to get the charger to start working.
Thank you… charger is dead- 0.0 volt increase when attached to battery. Hooked battery to Battery Tender and got voltage increase… up to 13.1V
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