More Alternator problems

[bizzard]

I'd temporarily wire the duff cabin alternator to the  engine start battery just before the RCR chap arrives, and then after he's fitted the new one and gone wire it back as how you want it   I read TB's post 95, hopefull he won't charge the call out fee.

[nicknorman]

4 minutes ago, Tony Brooks said:

Yes but that would give a lower voltage on the B+as long as one phase is working.

However if the thing has an open circuit rotor/brushes I suspect you will get battery voltage on both B+ and D+ terminals and as the A to D is still charging the batteries it will look like the thing is charging with no voltage difference.

Maybe RCR were measuring the small alternator output voltage on the large alternator's B+ but had not twigged that is what an A to B would cause.

These gizmos seem to offer very little that a decent regulated voltage, decent alternator wiring that a VSR will not, they just serve to make fault finding more difficult and hide faults.

Yea maybe, having the other alternator connected in parallel muddies the waters!

[Sea Dog]

11 minutes ago, nicknorman said:

Yea maybe, having the other alternator connected in parallel muddies the waters!

I've been saying that. Engine alt to engine battery, domestic alt to domestic bank. If one doesn't work, there's your fault, if both work it's the gizmo.

[Dr Bob]

1 hour ago, bizzard said:

I'd temporarily wire the duff cabin alternator to the  engine start battery just before the RCR chap arrives, and then after he's fitted the new one and gone wire it back as how you want it   I read TB's post 95, hopefull he won't charge the call out fee.

I think Bizz has the answer here! Unfortunately I told them it is the domestic and was told there would be a £45 fee. They are coming tomorrow am. Not a major drama as we were not planning to go out again before it warms up which is not till next wednesday.

I know everyone here is down on Sterling AtoBs but my 5 year experience on my prior boat was very good and on this boat the 90A alternator was only putting in 13.9V prior to fitting the AtoB so has been a big success in speeding up my charging over the last 6 months, and hasnt left me stranded anywhere as it allows the 55A to charge the domestics as well as the starter. Perhaps when I fitted the AtoB and it started to give me a lot more charging than I had before, that was the cause of the 90A giving up (making it work too hard). Having said that, the RCR engineer I talked to on the phone thinks it is the Sterling unit at fault but I cant quite understand that as both alternators feed into the same stud (why would one give power and the other not?). Fully agree the sterling unit is muddying the waters in working out what is wrong. Remember though, the 90A alternator was not putting in the right absorption voltage when we first got the boat so it has to be suspect in the full story.....and now is not delivering any current.

Agree the way to determine it is to take the AtoB out of circuit......I'll leave it to RCR tomorrow. I am happy to measure things but spanners on electrics is above my pay grade.

[nicknorman]

9 minutes ago, Dr Bob said:

I know everyone here is down on Sterling AtoBs but my 5 year experience on my prior boat was very good and on this boat the 90A alternator was only putting in 13.9V prior to fitting the AtoB so has been a big success in speeding up my charging over the last 6 months, and hasnt left me stranded anywhere as it allows the 55A to charge the domestics as well as the starter. Perhaps when I fitted the AtoB and it started to give me a lot more charging than I had before, that was the cause of the 90A giving up (making it work too hard). Having said that, the RCR engineer I talked to on the phone thinks it is the Sterling unit at fault but I cant quite understand that as both alternators feed into the same stud (why would one give power and the other not?). Fully agree the sterling unit is muddying the waters in working out what is wrong. Remember though, the 90A alternator was not putting in the right absorption voltage when we first got the boat so it has to be suspect in the full story.....and now is not delivering any current.

Yeabut that was probably because the 90A alt had a blown diode when you first got the boat. And now it has lots of blown diodes!

[Dr Bob]

29 minutes ago, nicknorman said:

Yeabut that was probably because the 90A alt had a blown diode when you first got the boat. And now it has lots of blown diodes!

.......well at least I got another 6 months out of it .......and learnt a lot from this thread...so its not all doom and gloom. I hope it is the 90A one caput.....as then I know it is fixed when I get a new one.

[WotEver]

15 minutes ago, Dr Bob said:

.......well at least I got another 6 months out of it .......and learnt a lot from this thread...so its not all doom and gloom. I hope it is the 90A one caput.....as then I know it is fixed when I get a new one.

And keep the A2B out of the circuit - it’s not required. 

16 minutes ago, Dr Bob said:

well at least I got another 6 months out of it

That’s doubtful. You’ve most likely been charging your batteries with the poor little 55A alternator ever since you fitted the snake oil A2B. 

[Dr Bob]

16 minutes ago, WotEver said:

 

That’s doubtful. You’ve most likely been charging your batteries with the poor little 55A alternator ever since you fitted the snake oil A2B. 

Certainly seen 65A charging current to the domestic bank last month so this is more likely to be recent unless a 55A can do more?

[nicknorman]

2 minutes ago, Dr Bob said:

Certainly seen 65A charging current to the domestic bank last month so this is more likely to be recent unless a 55A can do more?

The 55A is the nominal value and it could probably produce a bit more when cold and spinning fast. But of course we should remember that the current going into the A2B is more than that going out to the batteries (more voltage = less current for the same power). So more likely the 90A has 1 out of 3 phases still working.

[Sea Dog]

3 hours ago, Dr Bob said:

as both alternators feed into the same stud (why would one give power and the other not?).

How are you seeing the difference in output of the alternators if they're connected together at this stud? Are you connecting each individually to the same load for comparison purposes?

[WotEver]

18 minutes ago, Sea Dog said:

How are you seeing the difference in output of the alternators if they're connected together at this stud? Are you connecting each individually to the same load for comparison purposes?

He used his clamp meter on the alternator output cables. 

[Dr Bob]

2 hours ago, WotEver said:

He used his clamp meter on the alternator output cables. 

BTW, very impressed with the clamp meter. £27 from amazon. Easy to use and seems quiet accurate in the 14A range when compared to the battery monitor meter sensing current near the monitor shunt. 

[nicknorman]

3 minutes ago, Dr Bob said:

BTW, very impressed with the clamp meter. £27 from amazon. Easy to use and seems quiet accurate in the 14A range when compared to the battery monitor meter sensing current near the monitor shunt. 

Which model is it?

[Dr Bob]

15 minutes ago, nicknorman said:

Which model is it?

See your post number 67  My memory's awful as well. It's a red UNI-T from amazon. 

What has Rusty done to his avatar!!!!! Very ladylike!!!!!!

[WotEver]

2 minutes ago, Dr Bob said:

It's a red UNI-T

Yes but WHICH Uni-T?  UT203? UT210?

 

[rusty69]

2 hours ago, WotEver said:

Yes but WHICH Uni-T?  UT203? UT210?

 

Unitiy, unity we've all got unity. 

3 hours ago, Dr Bob said:

What has Rusty done to his avatar!!!!! Very ladylike!!!!!!

Its Faberge. 

[Sea Dog]

9 hours ago, Dr Bob said:

What has Rusty done to his avatar!!!!! Very ladylike!!!!!!

Oh, per-lease - don't egg him on. 

6 hours ago, rusty69 said:

Its Faberge. 

See what happens?

[Dr Bob]

9 hours ago, WotEver said:

Yes but WHICH Uni-T?  UT203? UT210?

 

Well, it's red! I'll look when I get up. Nice and small, fits in the hand well, and comes with a case.

Edit.... the duck didn't come with a case.

Edited March 30, 2018 by Dr Bob

[Sea Dog]

6 minutes ago, Dr Bob said:

Edit.... the duck didn't come with a case.

He's with a right "case" now though, eh! 

[Dr Bob]

The clamp meter was the UNI-T 210E

https://www.amazon.co.uk/gp/product/B00V9VL9CC/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

It was £35, bit more than I said. Delivered following day. 

[rusty69]

46 minutes ago, Sea Dog said:

Oh, per-lease - don't egg him on. 

See what happens?

Grumpy old Sea dog

[WotEver]

53 minutes ago, Dr Bob said:

The clamp meter was the UNI-T 210E

https://www.amazon.co.uk/gp/product/B00V9VL9CC/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

It was £35, bit more than I said. Delivered following day. 

It’s a good meter for boaters. I have the older UT203 which has coarser current ranges. 

[mad dog n' Englishman]

2 hours ago, Dr Bob said:

The clamp meter was the UNI-T 210E

Good meter but may have been better to go for the model that reads  DC current as well.

[rusty69]

2 minutes ago, mad dog n' Englishman said:

Good meter but may have been better to go for the model that reads  DC current as well.

What makes you think it doesn't?

[mad dog n' Englishman]

Hello, the description states, measure ac/dc voltage, ac current. No mention of dc current.