Charging problems - warning buzzer sounds

[FrigateCaptain]

Do you trust the meter ?

 

Nick

 

I've also checked with a multimeter too, the fridge warning light hasn't come on and there still seems plenty of power but can't understand the charging voltage

[Chris Pink]

take measurements at both battery banks and alternator B+ main output

 

Test 1: voltage with engine running, is it higher than with engine stopped.

 

Test 2: with engine running is the voltage at the batteries the same as at the alternator.

[Nickhlx]

I've also checked with a multimeter too, the fridge warning light hasn't come on and there still seems plenty of power but can't understand the charging voltage

 

What I was meaning is " do you trust what the meter is telling you and can you verify with a second (and/or a third) meter ?" ...

 

I built myself a calibrator with a 10 volt precision bandgap voltage reference, specifically so I could have a higher level of confidence in my several meters and was (not) surprised some were significantly out - I now trim periodically to ensure they are reading correctly, and immediately check with another meter if I get a reading that I am concerned about.

 

I don't think you can make decisions that may cost hours of labour and/or 10's or 100's of pounds based on one meter reading that might be porkies !

 

Nick

Edited May 8, 2012 by Nickhlx

[blodger]

Whether accurate or not Chris in post 27 is trying to establish from you whether the voltage is higher at the alternator than either or both battery banks so as to be able to proffer further advice/questions in a logical sequence maybe

[Nickhlx]

Whether accurate or not Chris in post 27 is trying to establish from you whether the voltage is higher at the alternator than either or both battery banks so as to be able to proffer further advice/questions in a logical sequence maybe

 

And quite correctly too !

 

My response, though, was to Frigate Captain, suggesting that he be confident in his meter before committing too much time and funds to what it is telling him...

 

Nick

[FrigateCaptain]

take measurements at both battery banks and alternator B+ main output

 

Test 1: voltage with engine running, is it higher than with engine stopped.

 

Test 2: with engine running is the voltage at the batteries the same as at the alternator.

 

Test one- yes by about .20v

 

Test two- yes by about .10v

 

Have also tried bypassing the relay, no different.

 

Open circuit test on batts with negs removed all showing the same.

 

Am massively confused

[blodger]

Test one- yes by about .20v

 

Test two- yes by about .10v

 

Have also tried bypassing the relay, no different.

 

Open circuit test on batts with negs removed all showing the same.

 

Am massively confused

Just more questions how is the relay actuated. By the charging light?

 

Does the alternator positive go through the isolator to the starter battery and do you still have to use the one or both isolator to connect the starter battery to the starter or do you now have a different isolator?

 

It seems your alt is now duff but somehow I think it is wired up wrong

[FrigateCaptain]

It's kicked in via the switched live on the ignition same as the lamp.

The multi switch is now gone, went when the relay was fitted.

Cable goes from b+ the starter battery terminal bypassing the isolater switch. From there it goes to the relay then to the domestics

[Nickhlx]

It seems that the wiring/connections is not introducing a problem, which leaves either the alternator being partially faulty ( diode ?) or the battery bank being in a fairly low state of charge, and/or the meter(s) being a bit pessimistic.

 

The warning light glow does suggest it may be alternator to me though as the meters are roughly in agreement, possibly being a bit light duty to charge all those batteries, and overheating ?

 

I think it would be worth ruling out the meter query with a reading from another meter to confirm, since that is relatively easy to do..

 

Nick

Edited May 8, 2012 by Nickhlx

[Chris Pink]

The next thing to do is to disconnect everything except the B+ to starter battery. Put a piece of wire directly from the battery to the warning light and make sure the other side of the warning light goes to alternator IND.

 

Measure the voltage at B+ and the battery +ve

 

Start the engine.

 

Does the light go out? Stay out?

 

Measure the two voltages again

 

Report back (4 voltage readings and 2 yes/nos)

 

(make sure you didn't connect warning light to W terminal on alternator)

[FrigateCaptain]

The next thing to do is to disconnect everything except the B+ to starter battery. Put a piece of wire directly from the battery to the warning light and make sure the other side of the warning light goes to alternator IND.

 

Measure the voltage at B+ and the battery +ve

 

Start the engine.

 

Does the light go out? Stay out?

 

Measure the two voltages again

 

Report back (4 voltage readings and 2 yes/nos)

 

(make sure you didn't connect warning light to W terminal on alternator)

 

This is all gonna be tricky with a 20 month old boy in tow, I'm gonna see if I can get someone out tomorrow.

 

Cheers any way folks

[FrigateCaptain]

I took the alternator to BAE to be tested today and they confirmed that although its working, its nowhere near what it should be.

 

It has now been replaced and everythings better, thanks everyone for your help and advice

[Nickhlx]

I took the alternator to BAE to be tested today and they confirmed that although its working, its nowhere near what it should be.

 

It has now been replaced and everythings better, thanks everyone for your help and advice

 

Glad it seems sorted now ..

 

Nick