Checking the Charge on a Battery

[VJLarson]

What setting on an OHM meter do you use to check the charge of a battery?

Thank you.

 

[JackandJanet]

You DO NOT use the "Ohm" range to check the battery charge. The Ohm range is for checking resistance in an UNPOWERED circuit or component.

You will set the multimeter to the DC voltage range. Some will automatically adjust for different voltages, but in some you have to set the range to a value that is a bit above the battery voltage. This is often the 20 V DC setting.

Then, you connect the common lead of the multimeter to the negative post of the battery and the positive lead of the multimeter to the positive post. A fully charged battery in a "resting state" will normally read about 12.7V. When I say "resting state", I mean that nothing is turned on and that the battery has been removed from any charging source for a significant time (about 6 hours).

A lower voltage reading indicates the battery is not at a fully charged state. 12.5V indicates an 80% charge state, 12.2V is 60% and so on.

If the battery reads higher than 12.7V, it has not rested long enough since being charged.

Multimeters come with an instruction booklet that tells you how to use them. Use it!

- Jack

 

[VJLarson]

Jack,
Thank you. I was asking the question for my husband and apparently we used the word OHM meter incorrectly. I'm very sorry about that. In spite of apparently frustrating you, you were very kind in giving us such good information and direction. I have printed it out but we will also look for the instruction booklet that apparently came with our multimeter and we will "use it!"

Thanks for your help and I'll try not to ask anymore questions.

Vicki

 

[JackandJanet]

Vicki! NO! I'm sorry if I sounded condescending or cross with you! I tend to do that without meaning to at times. I was just horrified at the thought of you connecting the Ohm function across a battery. That would fry the multimeter I think. Please, DON'T stop asking questions!

Here's a good link to instructions for using a multimeter: 3 Ways to Use a Multimeter: Measuring Ohms, Volts and Amps It shows an analog one (has a needle on a scale) but the digital ones work the same. You could probably find one for your brand, if you looked.

And, here's a link to a battery charge state chart for different kinds of batteries: Battery State-Of-Charge Chart For Voltage & Specific Gravity

It's amazing what you can find on the internet - some of it is actually TRUE!

- Jack

 

[VJLarson]

Jack,
Thanks again for all the information and for the links. They were very helpful and it's much appreciated.

We are leaving next week for the desert in northern Nevada and we are trying to be as informed and prepared as possible. We've done a lot of dry camping but this is the first time we've gone boon docking so far out in the middle of nowhere, with no service, and miles from any town.

Thanks again.
Vicki

 

[sam-HILO]

Asking questions

I always post and many times have to ask DH for the correct wording. Don't worry about asking questions. We all love to help and can always learn something no matter how many years we have owned RVS.