I took both of my batteries up to Advance Auto to get load tested because my multi-meter was showing them sitting at 12.0 and 12.1 while the analog meter on my load tester was showing them sitting at 13.0 and 13.1 and they are load testing fine on that gauge too, so there was a full volt discrepancy between the two. I didn't know which one was incorrect/correct so I figured I'd let Advance Auto be the tie breaker.
They hooked their load tester and before they did any testing one battery showed at 12.8 and the other at 12.7, so I know my multi-meter is most likely shot as the load tester was closer. So the voltage is perfect for both batteries, but then they did the load test.
The batteries are rated at 1100 MCA, so that's what they punch into the machine, then it does a load test. For one it said the actual MCA was 856 and the Result was to Replace Battery, and the second one load tested at 861 MCA and the obviously the result was the same.
So now my question is do I replace these batteries because the MCA tested low? 856 and 861 doesn't seem too bad to me and my engine has no problem at all starting and firing right off. As mentioned earlier I've tested specific gravity on all cells with a hydrometer on both batteries and they all test Good, no shorted or low cells, all are exactly the same.
I figure 1100 MCA is probably not true unless the battery is brand new (and maybe not even then) and since I think these batteries sat for a year and were never charged properly until I got them, they may be a little weak but again that MCA doesn't seem too bad to me. I assume the Amp Hr rating has gone down as well on these batteries, correct? I don't know the age of the batteries as there is no sticker on them that shows it.
What would you guys do, replace these or keep them? Will having the lower MCA affect/hurt my alternator at all, or is it strictly the cranking amperage that is affected. 12.7V and 12.8V seems pretty perfect to me, so I'm not sure if that's all that will affect the alternator or if the MCA will also.
Thanks again for all of the answers and any and all input is appreciated. Trying to learn as much about batteries as I can.
They hooked their load tester and before they did any testing one battery showed at 12.8 and the other at 12.7, so I know my multi-meter is most likely shot as the load tester was closer. So the voltage is perfect for both batteries, but then they did the load test.
The batteries are rated at 1100 MCA, so that's what they punch into the machine, then it does a load test. For one it said the actual MCA was 856 and the Result was to Replace Battery, and the second one load tested at 861 MCA and the obviously the result was the same.
So now my question is do I replace these batteries because the MCA tested low? 856 and 861 doesn't seem too bad to me and my engine has no problem at all starting and firing right off. As mentioned earlier I've tested specific gravity on all cells with a hydrometer on both batteries and they all test Good, no shorted or low cells, all are exactly the same.
I figure 1100 MCA is probably not true unless the battery is brand new (and maybe not even then) and since I think these batteries sat for a year and were never charged properly until I got them, they may be a little weak but again that MCA doesn't seem too bad to me. I assume the Amp Hr rating has gone down as well on these batteries, correct? I don't know the age of the batteries as there is no sticker on them that shows it.
What would you guys do, replace these or keep them? Will having the lower MCA affect/hurt my alternator at all, or is it strictly the cranking amperage that is affected. 12.7V and 12.8V seems pretty perfect to me, so I'm not sure if that's all that will affect the alternator or if the MCA will also.
Thanks again for all of the answers and any and all input is appreciated. Trying to learn as much about batteries as I can.