Honda ATV Forum banner

Battery Discharging

2390 Views 9 Replies 3 Participants Last post by  retro
I have been troubleshooting my fathers 1999 Honda TRX450R four wheeler for the last 2 days, but am confused:
Battery would go dead about every 4 days if you did not ride it, tested the battery and replaced it because it had a dead cell.
Four days later the new battery was dead.

Started to troubleshoot it yesterday using the troubleshooting procedures in the shop manual.
- Charged battery for 8 hours, meter reading was 13.1 volts. Tried to start it and the starter relay clicks but the started does not turn over.
- It starts on the first pull and idles normally.
- Conducted the “Current Leakage Inspection”, the current leakage was off the scale (my meter only reads to 20 Ma), so I assumed I had a short. I looked at all of the cables and could not find
a short. Pulled all of the fuses and still reads over 20 Ma.
- Disconnected the regulator/rectifier and conducted the “Current leakage test” again same result.
- I could not figure out how to test the ignition switch, but is seem to be working correctly. When turned to run the Neutral Indicator, Speedo, and hours show on the screen; and when you
turn the switch to off everything goes out.
- When changing the meter to DC Voltage I noticed that I am getting 11.2 volts DC when the meter is connected between the battery negative terminal and the Negative cable, the key was off
so I still assumed I had a short somewhere.
- I conducted the “Alternator Charging Coil” test and everything passed (.6 ohm on the stator coils) so I assume the stator is not the cause of a short.
- I disconnected the Regulator/Rectifier, and all three of the connections on the frame one at a time and I continued to have 11.2 volts on the meter between the negative cable and battery
- I pulled all four of the fuses one at a time and still had 11.2 volts.
- All of the above tests were with the ignition switch off, so I should not have had any voltage on the ground.
- I then tested from the negative terminal on the battery to the starter lug and had 10.7 volts, with the ignition switch off so it still seems like a short but I cannot figure out where the short
would be coming from. So I disconnected the power lead from the starter and test again, still 10.7 volts so the voltage must be coming through the ground system somewhere.

Any ideas on what to check next would be appreciated, at this point I am lost.

See less See more
1 - 4 of 10 Posts
Disconnect the solenoid and see if that solves the drain. Also loosen and clean the frame ground for the wiring harness and do the same for the negative cable motor ground. Let us know how it goes if you can and welcome to the forums!

EDIT: While the solenoid is disconnected check it with an ohms meter if ya got one, see if it is shorted. Also look up the starting section in the manual and do continuity tests on every component that you see on the diagram at the beginning of that section.
Thanks for the reply.

- I disconnected the solenoid and conducted the tests outlined in the service manual on page 19-7, continuity and voltage tests passed.
- I found the ground for the motor to frame and negative battery terminal to frame everything is clean and tight; I am still looking for the ground for the wiring harness. I did test
continuity from a wiring harness ground pin to the frame and got .3 ohm so I am pretty sure that ground is good as well.

- I did determine that my multimeter fuse was blown so after replacing I retested the "Battery Current Leakage" test on page 17-9, and am confused by the results: at initial
connection I am reading 6.9mA but it is fluctuating and within 15 seconds it stabilizes at 1.09 mA. The 6.9 reading is out of spec but the stabilized 1.09 reading is within, so I am
calling it good - What are you thoughts? :sad
- The "Charging Coil" test passed with .3 to .4 ohms on all three stator leads.
- The "Regulated Voltage Test" on page 17-8 failed, I was reading 18.3 VDC with the engine running at half throttle, which is way over the 15.5v limit. :sad
- The "Regulator/Rectifier" cable inspection on page 17-11 passed.

From the test results above, I think the Regulator/Rectifier is bad. Do you agree or am I missing something?

Thanks again for any ideas, suggestions you have.

See less See more
Yeah, it looks like the regulator/rectifier is bad. Great work diagnosing it by the way...! :)

You mentioned that the three charging coil resistance tests passed. Did you test between each of the three charging coil wires and ground? There should be no continuity to ground with each.

I am not familiar with that model so I'm guessing... is the frame ground for the wiring harness near the CDI?
Yes the three coil have to be between .1 and 1 ohm to each other and no continuity to ground. I will check for the ground near the CDI tomorrow.

  • Like
Reactions: 1
Does it crank over with the starter now? You didn't mention anything about that...
I pulled the starter off and pulled it apart and found one of the brushes is worn down to almost nothing and there was carbon dust everywhere. I cleaned everything and conducted continuity tests, everything passed so I reassembled and reinstalled. It turns over now but there is a short between the power lug and starter case, I think that the rubber grommet on the power lug is cracked.

I ordered a new Regulator/Rectifier and a starter rebuilt kit, so when they come in I will be able to get everything put back together and verify it's working correctly.
  • Like
Reactions: 1
1 - 4 of 10 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.