Hello Everyone,
I'm new to the forum. I have a 2001 Accord V6 with the 3.0L engine with 128k miles on it. I bought it last year from my niece. I had to buy a new battery the day I bought it. So the battery is 13 months old. Never had a problem with the battery until yesterday. I was sitting in a parking lot with the engine off but with the key in the on position to charge my phone while listening to the radio. Nothing unusual for me. I've slept in the car overnight with a usb fan on, radio playing and phones charging and woke up and it started right up. However yesterday after sitting for 45 mins I went to start the car and all it did was click. I checked the voltage and it was 11.9V. A guy gave me a jump and off I went. I had a hour commute home. No issues.

This morning the car started normal. Made my hour plus commute. I was sitting in a parking lot with the car running. I noticed the SRS and check engine light came on but was very dim and then the car died. I tried to start it and nothing but clicking. Checked voltage and it was 10.2 volts. I tightend the terminals and the voltage stayed the same. Someone gave me a jump and it fired right up. I started my commute home and about 20 minutes later those 2 lights came on and the car died again. While I was waiting for my sister to come jump me I put my tester on the battery with the key off. It read 11.9v then I turned the key to the on position and it only read 8.7v. Turned the key off and voltage went back to 11.9v. My sister showed up. We jumped the battery and again it started right up but this time I didn't make it 100 yards before it died. Sounds like the alternator to me because its not recharging the battery and the battery is only a year old. Once my son gets here I'm gonna take the battery to the store and have them test it or should I just replace the alternator?
sorry for such a long post but didn't want to leave out any details.
Thank you in advance

 

It does sound like an alternator issue.

Jump or charge the battery. Get the engine started and measure the voltage across the battery terminals with the engine running. It should be >13.3V. If you know how to do voltage drop, you may want to test voltage drop with the engine running from the large post on the alternator and the+ battery post just to rule out a bad battery cable or connections. I recommend Denso rebuilt alternators vs the stuff that you can buy from the parts store.

 

Thank you for your reply. So after I wrote the post. I went an bought a new alternator. When I got back to my car. I opened the hood and looked at the battery. I bought it 03/21. It had " 2 year full replacement warranty " written right on the side of it. So I took it back to Walmart and exchanged it for a new one. Hooked it up and the car started right up. I put my multi meter on it. Was reading 13.4 volts then I put a load on it. Headlights, stereo, wipers etc. It dropped to 12.7 volts. Turned everything off and it went back up to 13.6 so the old alternator seems to be working. I put the new alternator in the truck and I'm going to wait a couple of days before i return it just in case.
Thank you for your help.

 

The 12.7V when you put load on the alternator means the alternator is not putting out enough voltage to charge your battery. Just to be thorough, with the engine running, test for voltage between the large post on the alternator and the + post on the battery with the engine running. With a good cable, you should get close to zero volts. If the cable has large resistance, you would see voltage, say 0.5V or greater. Just be very careful when working around the belts with a running engine, because you can get a finger/hand severely hurt.

The box store's alternators can be bad out of the box or don't last that long, so that is why I'd source a Denso alternator if you have time. Option 2 is to find a place the rebuilds alternators.