I have 70K miles on my 2003 HCH 5 speed. I just replaced the 12V battery. When I did, I checked the voltage across the terminals with the car running to see if the alternator was responsible for the problem.

It measured 12.2V! So, I thought the alternator was indeed responsible for the problem. I drove to the Honda dealer with the intent of having it replaced. I got out of the car, checked the voltage again, and it was at 14V. Hmmm . . . so now the alternator is working.

I replaced the battery, and have been driving it for about two weeks. No failure-to-start problems yet. However, I have an electrical accessory (radar detector) that will give me visual indications when the voltage is low, and this has happened since replacing the battery. I am beginning to think I have an intermittent alternator problem. I am concerned that this will leave me stranded, and would like to fix it before my suspicions are confirmed by a dead battery that won't start the car.

Lastly, I have noticed that the HCH operates the alternator different than a typical car. It does not turn on the field coils of the alternator unless you turn the key to the 'start' position and the car starts. I found this out by push-starting the car when the old battery was dead one day. The engine started, but the alternator did not start charging even though the engine was running. I also learned that if I push-started it at the same time I turned they key to 'start', the engine would start and the car would turn on the alternator. I mention this because it is clear that the car does not simply turn on the alternator by switching they key to 'on', a different behavior than most cars.

So, I am suspicious that I simply have a case of worn-out brushes in the alternator. Has anybody else experienced alternator failures at the relatively-low mileage of 70K? Is it hard to remove and replace the alternator? Is this a DIY job for a mechanically-inclined person? Can the brushes alone be replaced easily?

 

Hi,

Are you sure there's a alternator in the HCH, I've read that it's the electric motor that replace the alternator. I really don't think that there's any alternator in the HCH. You can verify this by going to majectic honda and try to locate the alternator. I know there's a starter in case something fails, but I'm quite sure there's not alternator, I mean it's replace by the electric motor.

fanfaron

2003 civic hybrid cvt

 

fanfaron is absolutely correct. The gen 1 Civic hybrid does not have an alternator.

In all likelihood you have an electrical problem on your downstream 12V system or your DC-DC module is operating outside its specs (needs replacement) and that is causing an inadequate charge to be delivered to the 12V battery. Bad NiMH battery packs are also known to cause these types of issues. Heck, even a faulty BCM could cause this.

Charging occurs when the voltage baselines at 13.6 to 13.9 volts.

So, I would suggest it is time to take it to the dealer for 20 minutes worth of HDS diagnostics. They'll tell you for sure what's up and what needs to be done about it.

Cheers;

MSantos

 

Well, I guess it makes sense the car does not have an alternator. Why does it have a starter, though? I have never heard a gear-drive starter engage on the car.

I wish I could be as confident as you regarding the Honda dealer's competence. In reality, it is up to the electrical savvy of the technician being paid to do the diagnosis. There is nothing quite as satisfying as paying $100+ for 'no trouble found'.

Is it possible that the DC-DC converter and/or battery charge controller does not always output 14V? Perhaps it occasionally disconnects from the battery based on low input voltage (motor turning slow)?

I think a little better understanding of exactly how this charging system works would be good, before I go throwing money away. Can anyone point me to a block diagram or schematic? As an electrical engineer I have no problem understanding electronics.

I will reiterate that to date the car has not run the new battery down, but I did see some indication that it had low voltage while driving with the headlights on. If it actually did have low voltage it has to be intermittent for the battery to still have a charge.

 

A starter is included in the Civic hybrid so that it can crank the engine when the temperatures are too cold to exercise the IPU - mainly on the account of the operational range of the NiMH pack. Many of us have already used/heard the starter once or twice during the coldest winter months.

My confidence in the dealer network is not misplaced when it comes to such scenarios, mostly because the service people do very little to get the problems resolved. In other words, the procedural checklists leave very little room for technician experience because all they have to do is plug the car to the HDS station and follow the prompts. If something is wrong then the software literally recommends the solution.

So no worries there.

The only thing I would worry about is the ethical competence of a dealership and for that I always do a bit of homework before choosing a dealer for the "quality" service worthy of my money.

The best thing I can suggest is that you purchase a service manual. Printing and publishing that type of extensive copyrighted info is not legal particularly in a public forum setting such as GH. Besides, the information you need spans multiple modules. It is money well spent particularly for a person with electrical talents or affinities such as yourself.

But then you have the issue of the repair itself since the only means of performing proper servicing in this area is to have the equipment and diagnostic support that dealers possess. Many of the addressable and supported PID's are only thoroughly accessed by the HDS software. And that, denies the use of third party scanners and diagnostic stations because they will not be able to access the Hybrid specific info on the bus.


Anyhow, the power flow happens roughly in this sequence:
-The IMA stator motor/rotor provides the initial upstream power and is governed by the MCM with input from the BCM.
-This upstream power is then directed to the BCM which will then charge the HiMH pack. -In turn, the battery pack provides the nominal 148V level which will then be supplied to the DC-DC (downstream 12V power) and also the MCM which governs the assist function to propel the vehicle.

This is how it happens in a nut-shell.

Further to the DC-DC module, the charge pulses are not always steady. They will be triggered ON and OFF in varying duration and frequency as determined by the governing systems some of which I've already mentioned.

Cheers;

MSantos

 

It sounds like a reading of 12V at the battery does not necessarily indicate a failure, if I just happened to measure it when the 12V battery charging system was 'off'. It does usually measure 14V.

Thanks,

 

I usually see between 11.4V and 13.8 on the voltmeter I put in my car. (I have lots of drain on my battery from accessories, and maybe a bad cell in the battery). I do occassionally see 14V, but that is rare.

I think all civics for a while did weird things with charging to decrease load on the engine and increase fuel ecconomy. I don't think they run at 14.4 that often.

 

Update: The battery was weak, the charging system was fine - for a hybrid.

For those of us used to alternator behavior, the hybrid 12V charging system is different. It does sometimes turn off completely, leaving you with just battery voltage of 12V or less. To us old-timers that indicates a charging system problem. In a hybrid, it just indicates it is turned off at the moment.

 

This discussion might shed some light on why my headlights dim a bit when the IMA is called on. I have installed an aftermarket lighting control system which includes its' own relays for headlights and taillights, bypassing the stock relays. The unit automatically turns the lights on when it's dark. I elected to include the Daytime Running Lights feature, which has the headlights only on at all times. Rather than tap into the cars harness or fuse panel for the relay switched power, I connected directly to the battery (+) terminal.

Even so, I get this dimming of the headlights when the IMA kicks in. It's not a lot, but just enough to be annoying. Perhaps this is an indication that the 144v pack is isolated from the 12v system when IMA is working, leaving the native power of the 12v battery to handle some portion of the cars' electrical needs (and my DRL connection) on its own until the IMA is idle and the 144v battery can be spared from its main job.

This leads me to wonder if, with my DRL drawing directly on the resources of the 12v battery, it wouldn't be prudent to replace the tiny stock 12v battery with the full sized 12v battery the non-hybrid civic uses.

Alternately, perhaps I should track down the wire(s) which normally power the headlights (with the help of the Electrical Service Manual that I picked up recently) and tap in to those instead of going directly to the battery. I'm pretty sure I never had headlights dimming due to IMA use on the stock setup, so perhaps they are powered upstream from the circuit that tends the SOC of the 12v battery. I am a little more cautious about going this route without some council from more someone who understands the HCH electrical system better than I do. My understanding of electronics is pretty basic, and the HCH electrical system is relatively complicated. I wouldn't want to freak out the cars electrical monitoring system with a significant current draw in an unexpected time and place.

Any suggestions would be greatly appreciated.

 

Help please. yesterday i went to start my car and the "ready light" came on but when i put it in gear and hit the accelerator nothing happened. i called up the dealer and they said to jump start the car and it worked.
this is my first car and i am wondering why the battery died does the car have an alternator??? or none?i mean remove??