Testing Household Batteries

[etherhuffer]

So, with the help of YouTube I find that to test a battery properly, you add a resistor in line when checking voltage. Pretty cool, the load gives away a bad battery where simply voltage checking does not. My small multimeter only has 1.5 and 9V battery check settings. Has anyone tried this on 18V battery packs? I have a handheld vacuum, just got a new NiMH battery pack about a year ago, already not working. Charger puts out correct voltage. If I add a resistor in line, should I be able to test a battery pack in manner of single battery?

 

[Max]

If you measure a battery pack you get a sum of all of the cells. If everything is good you can see the total voltage and say it’s roughly ok. But if the total is not right you need to look at each cell individually to find the bad one(s).

BTW, putting a resistor in line implies a series resistor for the load and that is not correct. The load resistor should be in parallel to the battery. The load resistor needs to have the right resistance to draw the rated current from the battery, and the right wattage to safely dissipate the power from the battery.

 

[dogdog]

So, with the help of YouTube I find that to test a battery properly, you add a resistor in line when checking voltage. Pretty cool, the load gives away a bad battery where simply voltage checking does not. My small multimeter only has 1.5 and 9V battery check settings. Has anyone tried this on 18V battery packs? I have a handheld vacuum, just got a new NiMH battery pack about a year ago, already not working. Charger puts out correct voltage. If I add a resistor in line, should I be able to test a battery pack in manner of single battery?

What’s the logic in adding a resistor inline?
Pointless for a multimeter that have high impedance.

 

[etherhuffer]

The YouTube video I picked that up on stated the purpose was to add a load, as just testing voltage alone would not be sufficient. This problem actually solved itself late last night. I checked each cell in the battery pack, all were good. Tore open the vacuum and located switch that turns it on. Lo and behold a circuit board. I cleaned up the board and switch with DeOxit. Put all back together and it ran fine for 5 secs before the board/switch emitted smoke and died. Diagnosis complete-buy new vacuum!

 

[Max]

The YouTube video I picked that up on stated the purpose was to add a load, as just testing voltage alone would not be sufficient. This problem actually solved itself late last night. I checked each cell in the battery pack, all were good. Tore open the vacuum and located switch that turns it on. Lo and behold a circuit board. I cleaned up the board and switch with DeOxit. Put all back together and it ran fine for 5 secs before the board/switch emitted smoke and died. Diagnosis complete-buy new vacuum!

Sorry to hear the board smoked. Deoxit is something that should be used sparingly on switch contacts only.

 

[etherhuffer]

Sorry to hear the board smoked. Deoxit is something that should be used sparingly on switch contacts only.

I likely should have used just alcohol. In the old days there was freon in a can but have not looked for that in years.

 

[engineer2]

Diagnosis complete-buy new vacuum!

What tool platform are you on and do they make a vacuum that will work for you? That way your lithium ion batteries can be shared.

I bought the little Makita 18V stick vacuum on a whim and we use it all the time for kitchen crumbs and pet hair.

 

[etherhuffer]

What tool platform are you on and do they make a vacuum that will work for you? That way your lithium ion batteries can be shared.

I bought the little Makita 18V stick vacuum on a whim and we use it all the time for kitchen crumbs and pet hair.

None right now. The Mrs says next vacuum will be quiet and hold a charge, but that was it. I should look to see what 18V batteries they use.

 

[engineer2]

We were thinking about buying a more heavy duty battery-powered vacuum. Read the online reviews!
We were going to buy a Dyson, but there were too many reports of battery problems.