Battery Test Results
Aug 18, 2022 08:20:59 #
I had to switch meters and start over, but the results are below. This is just one test with only two batteries and one multimeter, but the results are interesting. The nominal voltage is 7.6, and the lowest voltage in the chart below is 8.44, so it's still okay.
Related - I posted about a week ago that the battery in my Z fc went dead after a week. That's not true. After two weeks, the battery is still in good condition. I don't know what happened the first time around.
Related - I posted about a week ago that the battery in my Z fc went dead after a week. That's not true. After two weeks, the battery is still in good condition. I don't know what happened the first time around.
Aug 18, 2022 08:25:21 #
Probably 7.6v under load....
What's the no-load voltage in your car battery that is rated at "12v"?
What's the no-load voltage in your car battery that is rated at "12v"?
Aug 18, 2022 08:29:26 #
Longshadow wrote:
Probably 7.6v under load....
What's the no-load voltage in your car battery that is rated at "12v"?
What's the no-load voltage in your car battery that is rated at "12v"?
Car battery - close to 14v.
Aug 18, 2022 08:33:00 #
So I suppose one has to understand the method used to obtain the "rated voltage".
Aug 18, 2022 09:27:28 #
The li-ion battery when fully charged voltage is about 4.2V so it would be 8.4V for 2 cell pack.
After it discharges to about 80% remaining the voltage would be 3.8-3.7V per cell so it would be either 7.4 or 7.6V. At about 20% remaining the voltage starts to drop further. So the 7.4-7.5V is the range your battery pack voltage will be for most of its operating time.
Besides I suspect your new meter is reading a bit high.
After it discharges to about 80% remaining the voltage would be 3.8-3.7V per cell so it would be either 7.4 or 7.6V. At about 20% remaining the voltage starts to drop further. So the 7.4-7.5V is the range your battery pack voltage will be for most of its operating time.
Besides I suspect your new meter is reading a bit high.
Aug 18, 2022 09:28:30 #
bikinkawboy
Loc: north central Missouri
Actually no load 12V wet cell battery voltage is around 12.5V. Under heavy load like starting something a bit above 11V. The 14.5 voltage is charging voltage. Needs to be at least 10% above battery voltage to charge the battery fully.
Aug 18, 2022 09:42:15 #
bikinkawboy wrote:
Actually no load 12V wet cell battery voltage is around 12.5V. Under heavy load like starting something a bit above 11V. The 14.5 voltage is charging voltage. Needs to be at least 10% above battery voltage to charge the battery fully.
A 12V lead acid battery would measure 13.6V fully charge with no load. But it doesn't stay in this condition for very long. Like you said, a no load voltage would be somewhat higher than 12V most of the time. If no load voltage is less than 12V even 11.9 the battery is considered dead.
Aug 18, 2022 10:10:41 #
TMI! 
My conclusion is that leaving a battery in an unplugged charger will slowly drain the battery. "That is all ye know on earth, and all ye need to know." (John Keats)
My conclusion is that leaving a battery in an unplugged charger will slowly drain the battery. "That is all ye know on earth, and all ye need to know." (John Keats)
Aug 18, 2022 11:54:04 #
jerryc41 wrote:
TMI!
My conclusion is that leaving a battery in an unplugged charger will slowly drain the battery. "That is all ye know on earth, and all ye need to know." (John Keats)
My conclusion is that leaving a battery in an unplugged charger will slowly drain the battery. "That is all ye know on earth, and all ye need to know." (John Keats)
and with your charger the drain is not significant.
Aug 19, 2022 06:35:43 #
jerryc41 wrote:
TMI!
My conclusion is that leaving a battery in an unplugged charger will slowly drain the battery. "That is all ye know on earth, and all ye need to know." (John Keats)
My conclusion is that leaving a battery in an unplugged charger will slowly drain the battery. "That is all ye know on earth, and all ye need to know." (John Keats)
why would you do that? seems dumb to me. I always put them back in their plastic cases when they are charged.
Aug 19, 2022 07:36:53 #
bikinkawboy wrote:
Actually no load 12V wet cell battery voltage is around 12.5V. Under heavy load like starting something a bit above 11V. The 14.5 voltage is charging voltage. Needs to be at least 10% above battery voltage to charge the battery fully.
Truck alternators, such as the very popular Leece-Neville, always had adjustable regulators. 13.7v to 14.2v. If you were running an over-the-road operation where there are fewer stops and starts of the engine you set it to 13.7v for better battery life. For short haul, where you would want quicker recovery, you used 14.2v. All ancient technology now. Back then (70's & 80's) a 105 amp alternator was considered big. Now days most cars have bigger alternators and regulators are a thing of the past. The computer controls charging, in part for fuel mileage and in part to control charging rate to prevent overheating the battery and shortening its life.
Aug 19, 2022 09:20:08 #
foathog wrote:
why would you do that? seems dumb to me. I always put them back in their plastic cases when they are charged.
We learn through experimentation. The battery in the charger is down to 8.35 today.
Aug 19, 2022 09:26:32 #
jerryc41 wrote:
We learn through experimentation. The battery in the charger is down to 8.35 today.
With your result although it's not significant I wouldn't want to leave it in the charger.
Aug 19, 2022 09:28:53 #
BebuLamar wrote:
With your result although it's not significant I wouldn't want to leave it in the charger.
Aug 19, 2022 10:07:19 #
Testing batteries with a multimeter and no load attached, will tell you nothing about the remaining performance of the battery.
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