Discussion in 'Electrical' started by Kenerator, May 20, 2019.
After running for about 10 minutes, I turned it off and restarted like nothing wrong.
When you get home you can load test the battery without taking to a parts store. Just have a charger ready to charge it back up if you need to get a new battery.
Thanks to everyone for the input.
Stamp, what is your method of load testing? I have a charger.
Aside from testing the output voltage with a volt meter, are there any other tests I can do to test for a failing alternator?
Battery is 5 yrs old. I'm thinking just replace it for good measure. We tow a boat in the heat of summer and I'd hate to have a marginal battery under the hood.
Thank goodness it's not raining like it was yesterday!
See, you didn't say that part about the battery in your post. You made it sound like it was fairly new, you cleaned the cables a month back. 5 years is at the limit, some these days act up sooner. I'd replace the battery, let them check the charging where you buy it. As always, ask for a new one from back of rack. Those are the newest grp 65's. They might argue about that, but insist, it's your $.
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Normally you load test a fully charged battery at 1/2 the CCA rating for 15 seconds at 80F and read the ending battery voltage. Since most of us don't have the equipment to put a 400-500 amp load on the battery we can use the next best thing - the starter. It will usually draw between 300-400 amps once the engine is turning.
To do this you need to disable the fuel or spark - fuel is easiest. Remove the fuse for the fuel pump.
Connect your voltmeter to the battery terminals (should be clean and tight to the post) set meter to volts dc.
Crank engine for 25 seconds while watching the battery voltage. Let the starter cool for 2 minutes (important - allows the brushes and commutator to cool off some, it will get warm/hot). Crank the engine again for 25 seconds. If the battery voltage drops below 10.5 volts at any time during either cranking cycle the battery is low on cranking amps and should be replaced. You would adjust the voltage threshold based on ambient temps - cold temp the ending voltage is lower.
If it is, charge the battery back up, reinsert the fuel pump fuse and go by another battery. I recommend a maintenance free battery over the vented wet cell. These have no maintenance issues with corrosion on the posts.
That is good news, Ken. But that doesn't mean it will start again on its own battery power. You need to load test the battery and charging system.
I replaced the battery with a new Interstate battery from Costco. $94.00. Also tested the alternator with a volt meter. At 1500-1800 RPM it read a steady 14.2 volts no electrical on and a steady 13.9 with the air cond, rear air, high beams, interior lights and the radio turned on. Measured between the + and - on the battery. I ran out of light and time, so I'll test between the alternator + and ground this weekend.
Thanks again to moose, stamp and Don for your insights and assistance.
Nice job on the Costco battery purchase, Ken. I think Costco only carries Interstate now, and it is the best battery deal.
By your electrical measurement readings, it would appear the charging system is normal, and the culprit was a faulty battery.
FYI: Interstate does not manufacture a battery. It is just a marketing company.
The Interstate battery is made by Johnson Controls, as are many other batteries.
Good thing about Costco also is they never fight with you on a return. Everybody else seems to.
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Steve, if we could only convince Costco to install the batteries they sell.
A battery change is a big deal for me now.
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