I have a 2007 Honda Accord LX. After running several errands with 5 to 10 minutes of city driving between each stop, it wouldn’t start after the final stop (20 minutes in the grocery store). The lights were not left on, and no accessories were left on. The outdoor temperature was about 50 degrees F. It would turn over a couple of times before finally dying. I got a jump from a stranger, and it fired right up. I drove the couple of miles home, turned it off, and tried restarting, but it behaved the same as it had at the grocery store. I put the battery charger on it (set to the 10amp setting) and after several hours of charging it started (I tried after 10 minutes, but it again behaved like it had at the grocery store). Once the battery was charged and the car started I took it to two different auto parts stores. They both tested the battery, alternator, and starter and reported all was well. This is the second time this has happened in the past month. After the first time, I was advised to replace the battery, which I did.
Check for corrosion close to the positive battery terminal, pull back the red cover on the terminal, I have seen corrosion build up back a little bit from the battery terminal on the cable…
@Tester Thanks! Short drives could be part of the problem, but the car has been driven in this manner for years, and this problem has only manifested itself in the last month. Nevertheless, I think I will get a battery maintainer to extend the battery’s life.
Aren’t there some relays in Hondas that can cause problems? Fuel pump relay?
Just captain obvious but the battery is not being charged. The question is why. I think an evaluation by a real mechanic is in order not a parts store clerk. So is it short trips that didn’t cause a problem before, corroded cables, an alternator not putting out, etc? Using a $20 plug in volt meter will tell you if the alternator is putting out 13 plus volts while driving as a clue.
@texases Thanks! How might one diagnose such a problem (given that the relay hasn’t failed completely)?
Yes, I think it is becoming discharged somehow. However, it is getting charged at least a little, as I don’t think the car could run just off of the battery for two weeks of daily driving with multiple starts per day. I wonder if there is a dead spot in the alternator or starter so that they test good most of the time, but if they stop in a specific position they drain the battery?
The cables around the battery look good, but I haven’t crawled under the car to look at the connection to the starter.
At least at idle the alternator is putting out 14.2v, presumably higher (or at least not lower) at higher RPMs, but I can have someone rev the engine while I watch the volt meter and see what happens.
That indicates the battery wasn’t fully charged.
Tester
If this was an “older” Honda, that would be a possible problem, but those problematic relays were in cars that they manufactured in the '90s. It’s not impossible for this to be the problem in a 2007 Honda, but I think Tester’s observation is right on target:
+1
Time for an alternator test by an actual mechanic (not a guy from the parts store), and if the alternator tests out okay, then it’s time for a new battery.
I’m just a pin-head diyer, complete knucklehead. But I own an older Corolla, which has no dashboard warning lights & cranks & starts as well as it did when new. However I have had no- or slow-crank problems over the years and repaired them myself. If I had that problem here’s what I’d do (Fair warning, a few of the folks posting here probably think you should just ignore me ) Presuming you have a conventional gasoline engine configuration, not hybrid or EV. )
- Verify the battery measures appx 12.6 volt before the first start of the day, then 13.5 -15.5 volts after starting the engine.
- Verify both starter motor terminals measure at least 10.5 volts with the key in “start”. Probe terminal to starter case.
If both tests pass, my guess is your starter motor is the problem.
12.7v
14.2v
That looks good. If consistent day to day, unlikely to be the battery or alternator.
The OP has stated that they have had the car for years…
Welcome to the forum, but your answer is very suspicious…
Thanks for everyone’s helpful input. Here is an update of the situation. I have ordered a battery maintainer as suggested and will install it permanently under the hood so we just have to plug it into 110vac when parked in the garage. I also got a device that plugs into the cigarette lighter outlet that displays the system voltage. As expected, most of the time while driving around it reads 14.1v regardless of speed or engine RPM, however, it will sometimes drop down to as low as 12.5v! This happened both while driving, as well as at stop lights (but not at every stop light at which I stopped). The times it did happen at a light it took several seconds after stopping for the voltage to drop, and it took several seconds after starting to accelerate for the voltage to return to 14.1v. I am guessing that this indicates that the alternator is intermittently failing, or the belt is slipping. Unfortunately, I have been unable to duplicate the problem while parked in my garage where I could observe if the belt was slipping.
Your vehicle has a battery current sensor. If this sensor is faulty it can cause erratic charging voltage from the alternator.
https://shop.advanceautoparts.com/find/2007-honda-accord-battery-current-sensors
Erratic Charging : A malfunctioning Battery Current Sensor can result in variable charging of the vehicle’s battery. This means the battery may receive a different and incorrect charge, resulting in power fluctuations. In some cases, the battery may become overcharged, leading to electrolyte loss and damage. Alternately, the battery may be undercharged, causing it to run at a lower capacity and potentially leading to a dead battery.
Tester
Thanks @Tester! Unfortunately, I don’t think my model has such a device. When I click on either product in the link you provided it says that it doesn’t fit my vehicle:
https://shop.advanceautoparts.com/p/carquest-premium-battery-current-sensor-cta1083/12546005-P?vehicleIdSearch=369319&isAllVehicle=false
Possibly a function of Honda’s dual mode charging system, this is used to improve fuel economy. To cancel the low voltage mode switch on the headlights, the electronic load detection module will increase the alternator voltage to normal mode.
I drove around for a bit with the headlights on, and as you suggested, the system voltage did not drop below about 13.9v (although better than 12.5v, this does seem a little low). Time will tell if this is the solution to the original problem (battery becoming discharged over time to the extent that the vehicle will not start). Also, I read a little about the Dual Mode Charging System after you mentioned it, and I am not sure that it is working in my vehicle. For one, for low output mode, the intake air temperature must be above 68 degrees F, and the ambient temperature today when this was happening was 47. Also, shouldn’t the low output mode generally be on for more than a few seconds at a time under normal operating conditions?
Keep us informed OP. Others having this same problem may find this thread using the forum search feature.