Battery condition

[chinook35]

Here’s something interesting   I pulled my batteries in the fall and have them inside. I always put them on charge to get them up to the top. I got a reading on a multimeter that showed both batteries needed replacing. I used a different multimeter and got good resting voltage. So I bought a battery tester ( should have one anyway )  now the good part. I tested both batteries using the studs  said replace on both.  I retested using the posts and both batteries tested good. Did test twice to verify   I use the posts for starting and the studs for electronics   Go figure. The $35 dollar tester saved me $200 +

[lrg355]

Interesting.  Perhaps not good contact or hidden corrosion on the steel screw terminals.  Does the battery tester just clamp on ?   If I't does try a ring terminal with a short piece of cable screwed tightly to  the threaded stud.  Clamp to  the cable for better contact. 

[Bozeman Bob]

Voltage and amperage are two different animals. I can put 8 D cell  volt batteries in a series and get 12 volts , not going to start your engine . A multimeter is pretty much useless in giving you the actual condition , it's all about the amps . How many amps does your starter draw ?  I have a good idea , do you ? 

[chinook35]

23 minutes ago, Bozeman Bob said:

Voltage and amperage are two different animals. I can put 8 D cell  volt batteries in a series and get 12 volts , not going to start your engine . A multimeter is pretty much useless in giving you the actual condition , it's all about the amps . How many amps does your starter draw ?  I have a good idea , do you ? 

As stated  the batteries are out of the boat   The starter and starting have never been an issue. I wanted to check the condition of the batteries before trouble starts. A fully charged battery at rest should read 12.6 volts or higher   I was getting low voltage readings on 1 multimeter and good readings on another. Now have a new multimeter that verified the low reading meter was junk   I bought a load test battery tester.  It shows good batteries. The stud problem was loose nuts. Tighten them up and it’s all good. Starter draw is an indication of starter condition. Wear on end bearings , worn brushes , starter drive.  No two will have the same value. 

[Shakemsam]

The only accurate way to test a battery is while it is under load..IMO

[chinook35]

I say again. I bought a battery load tester. It places a load on a battery ( in vehicle or out ) to test for weak cells.  The multimeter voltage can only tell the state of charge   It can determine if a battery is capable of holding a charge while at rest. If it can’t maintain a full charge it would be useful as an anchor 

[Bozeman Bob]

In the 40 years of selling tools and equipment to garages I have never ever witnessed a mechanic use a multi meter to check a battery , even if they did not have a load tester. As a matter of fact I just left a shop where they had a battery that showed 12.6  , put a load tester on it and that showed 62 amps out of a 200 amp battery. Not going to work on a starter that draws more than that number . 

 

Edited December 13, 2022 by Bozeman Bob

[lost a lure]

I hope you guys are better at fishing than troubleshooting electrical.

[chinook35]

Thanks for your worthless comment  

[sherman brown]

a lead acid battery can be low on water and still show good when tested without doing a load test. this just shows the amount of water is charged. but when trying to start a motor is doesn't start. or put it on a load test and it will show bad every time.

 

we made the mistake of going to Erie with 2 batteries that had been on the onboard charger all winter and showed fully charged. we docked the boat and plugged up the charger and it showed fully charged the next morning and the motor started great. but we were having problems and shut it down. when we started to go the motor would only crank over real slow then stop. we found the fluid level to be very low and about 1" or more below the plates in the battery. even though we filled these batteries with distilled water and tried charging them it didn't help.

 

the moral is if your motor doesn't start out on Erie you better have towing insurance through boatus.com with trailer assist for around 100.00 per year or have a good kicker. we had a mercury 9.9 4 stroke, so we trolled where we broke down but just wasn't far enough out to catch many fish. then we used it to get back in.

[lost a lure]

8 hours ago, chinook35 said:

Thanks for your worthless comment  

Lighten up, Francis

[chinook35]

Ok  karen

[KoenFischer]

That's quite an interesting battery story you've shared here! It just goes to show how nuanced dealing with batteries can be. Having a battery tester on hand is indeed a wise move for any boat owner, and your experience is a perfect example of why.It's fascinating how different testing methods can yield contrasting results. Your $35 battery tester turned out to be a valuable tool that saved you a significant amount of money. That's a win in my book!Batteries can sometimes be a bit finicky, and your story highlights the importance of thorough testing. For anyone in need of battery solutions, tech-battery is a great resource to explore. Thanks for sharing your experience, even if it's been a year.

Edited November 15, 2023 by KoenFischer