Overcharging battery

[mottleemob]

I had problems with alternator pumping 15+volts into battery so a new alternator fitted as well as a new battery as the old one died probably from being boiled dry but i am still having exactly the same problem with new alternator and battery. Any ides as to what maybe wrong surely 2 alternators wouldn't couldn't be faulty in the same way.
cheers phil

 

[scooba_285]

im not sure on this but im sure oldtony will give an in depth explaination

 

[Old.Tony]

The regulator should be getting instructions from the ECU to provide more output.

It would be interesting to see what your ECU thinks the voltage is. If it thinks the voltage is only 14-odd volts, there's a problem with the wiring between the alternator and the ECU.

This is only if the alternator/regulator can be commanded by the ECU in the D22. I can't see why it wouldn't.

Do you have a Scangauge? If not, do you want to put my bluetooth adapter on and get some readings?

 

[mottleemob]

Tony no i dont have a scangauge your bluetooth sounds good
cheers phil

 

[Old.Tony]

Then we need to arrange a time and place to meet up, perhaps coffee. Tomorrow sound ok?

 

[mottleemob]

Unfortunately i will be in Sydney this weekend would the following saturday be ok with you
if so i will pm my phone number to arrange a time and place
cheers phil

 

[Old.Tony]

Doesn't look like I have anything on that weekend. I'm also fine most afternoons. I don't work full-time any more.

 

[mottleemob]

Tony
Received your PM will ring you later in week
thanks phil

 

[Dave]

Then we need to arrange a time and place to meet up, perhaps coffee. Tomorrow sound ok?

Sounds like a date. Haha.

 

[Krankin]

Sounds like a date. Haha.

.

 

[KraftyPg]

Flag Flag Flag, that's off topic, how dare you lot go off topic

 

[Krankin]

flag flag flag, that's off topic, how dare you lot go off topic

sssssshhhhhhhhhhhhhhhh

 

[Dave]

The regulators are built into the alternator.

Let us know how you go.

 

[Old.Tony]

Sounds like a date. Haha.

I can't believe you're jealous, Dave.

Just look a little longer at your avatar mate, you'll be ok.

You should have said something earlier. I'm sure they'd enjoy meeting up with you too.

 

[Old.Tony]

Well, despite the bloody rain we had a go at the problem and couldn't get an answer.

We were looking to see if we could get the ECU to tell us what voltage it thought the battery voltage was at but my bluetooth OBD adapter wouldn't fire up in the 2006 D22. I've a feeling that the D22's OBD port is not OBD-II compliant or it's missing a power line that the OBD adapter is needing (because the OBD port in my 2009 D40 - which we then tried the adapter in and it worked) does have the power lines. I had a feel of the back of the OBD plug in the D22 and it seemed a little light on wiring.

Anyway, because we couldn't tell what the ECU was actually reading, and because it was a new battery and a new alternator (both were nice and shiny) we're assuming that there's some resistance somewhere between the power and the ECU, causing the ECU to THINK that the voltage is lower than it actually is and therefore instruct the alternator (regulator is built-in) to provide a higher voltage.

We had the engine running and the air conditioning going. Measured at the battery, my multimeter reported voltages of 15.6-15.8V. That's going to kill the battery fast. After turning on the headlights the voltage fluctuated from 14.6 to 15.2V. I think the lights should stay on for now!

What I didn't say was that I'd previously (about 10 mins beforehand) checked my multimeter with a lab power supply, and it's accurate to within 0.05 of a volt (at 14.10V, my multimeter reads 14.15V), so my multimeter reading is very close.

So, where to go from here? The connections will be checked (in particular the earth points), but I was thinking that you should replace the fuse to the ECU. Don't just check it, pull it and put a new one in. Some fuses (either close to or under-rated) get warm, and when they get warm their resistance increases dramatically, lowering the voltage to whatever is being supplied.

It's an easy, cheap thing to try.

Does anyone else have any ideas what could be causing this?

 

[robmacca]

Clutching at straws here, but have u tried measuring the voltage of the sensor wire at the actual alternator? If it's like some other cars that I've been told about, it may not be seeing the true voltage due to a high resistance somewhere or try connecting a temp bridge straight from the battery to the Alternator sensor wire and then recheck voltage output......

if that doesn't work, then I would be looking at your earthing straps from Engine to body to battery and test as u go to see if the output voltage changes..... or with engine off, measure the resistance from the Alternator frame to the negative terminal of battery and see what u get....

just some ideas I'd try at least


how many kms do u have on the car?

 

[mottleemob]

Problwm solved took it to an auto elec this morning found problem was a bad connection at rear of fuse box .all good now .Thanks guys for your help
cheers phil