More Alternator problems

[rusty69]

10 minutes ago, mad dog n' Englishman said:

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

Will have to await Dr Bob with the manual, but I would be very surprised if it didn't measure DC current.

[Dr Bob]

22 minutes ago, mad dog n' Englishman said:

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

Yes it did in that link....

......but the there is another link

https://www.amazon.co.uk/UNI-T-UT210E-Current-Meters-Capacitance/dp/B00O1Q2HOQ/ref=sr_1_5?s=diy&ie=UTF8&qid=1522407196&sr=1-5&keywords=clamp+meter+dc+current&dpID=41sD0XebR4L&preST=_SY300_QL70_&dpSrc=srch

for the same meter that says it does DC as well.

I  bought the one that does DC current.....and it did it very well.

[mad dog n' Englishman]

I had to look carefully when buying similar a few years ago. Many could not read dc current. I was surprised. Mine is the Uni t 203. this does read dc current

[rusty69]

1 minute ago, mad dog n' Englishman said:

Mine is the Uni t 203. this does read dc current

Yes, I have the uni-t203.Twas no fluke, but i'm not as rich as Dr Bob.

Has you're alternating man been round yet Dr Bob? 

[Dr Bob]

8 minutes ago, rusty69 said:

Yes, I have the uni-t203.Twas no fluke, but i'm not as rich as Dr Bob.

Has you're alternating man been round yet Dr Bob? 

Yes, just been and gone. Agreed with me that 90A is duff. Called Beta to order a new one but they are closed for easter so cant order one 'till tuesday so wont get it until Wednesday.....and a new one is expensive ....£200 ish! I will get a new one then get the old one serviced and use as a spare. Not covered by RCR unfortunately.

[rusty69]

1 minute ago, Dr Bob said:

Yes, just been and gone. Agreed with me that 90A is duff. Called Beta to order a new one but they are closed for easter so cant order one 'till tuesday so wont get it until Wednesday.....and a new one is expensive ....£200 ish! I will get a new one then get the old one serviced and use as a spare. Not covered by RCR unfortunately.

Ouch. Well at least you know now. Did he think the diodes/regulator  are shot? Maybe cheaper to get refurbished, although a spare is always useful 

The moral of the story is everyone should own a digital clamp meter or infrequent red thermomoter. 

[Dr Bob]

1 minute ago, rusty69 said:

Ouch. Well at least you know now. Did he think the diodes/regulator  are shot? Maybe cheaper to get refurbished, although a spare is always useful 

The moral of the story is everyone should own a digital clamp meter or infrequent red thermomoter. 

Yes, I am sure it would be cheaper to get refurbished but at least this way I will have the spare. Just did a quick search on replacement alternators for the Beta 43. It looks like the Beta replacement is £200 ish. Midland Chandlers are asking £355 for a replacement but not sure what make it is. Balmar are looking at £600+ .....eek!

You are right, if it wasnt for the infrequent red thermometer, I wouldnt have noticed the problem until the small alternator burnt out, and without the clamp meter not easy to diagnose the problem.

[WotEver]

1 hour ago, mad dog n' Englishman said:

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

It does. That spec is a misprint. 

[ditchcrawler]

1 hour ago, mad dog n' Englishman said:

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

I thought that was what the 14 Amp were

[Sir Nibble]

I'm not convinced about any of this. I have no direct experience of this sterling unit but as I understand it isn't it supposed to load both alternators to 13V to ensure max field? According to the voltages on your alternators that's not happening is it. The small Nippon Denso 55A unit is regulated quite high at about 14.6V, the larger Bosch one at around 14.4V. So, the small alternator will be working flat out up to a voltage 0.2V above where the Bosch begins to idle. The big alternator will never have any work to do except when the load demand is above 55A. To test the performance of the big alternator you need to kill the output of the small one by removing the multiplug. It is very unusual for a diode to fail on these Bosch units, when they go it is nearly always because the brushes and slip rings have worn out and they shut down completely. At the moment it seems to be behaving much as I would expect if you just linked the two outputs, with the alternator with the higher regulator setting doing all the work.

Edited April 2, 2018 by Sir Nibble

[Dr Bob]

2 minutes ago, Sir Nibble said:

I'm not convinced about any of this. I have no direct experience of this sterling unit but as I understand it isn't it supposed to load both alternators to 13V to ensure max field? According to the voltages on your alternators that's not happening is it. The small Nippon Denso 55A unit is regulated quite high at about 14.6V, the larger Bosch one at around 14.4V. So, the small alternator will be working flat out up to a voltage 0.2V above where the Bosch begins to idle. The big alternator will never have any work to do except when the load demand is above 55A. To test the performance of the big alternator you need to kill the output of the small one by removing the multiplug. It is very unusual for a diode to fail on these Bosch units, when they go it is nearly always because the brushes and slip rings have worn out and they shut down completely. At the moment it seems to be behaving much as I would expect if you just linked the two outputs, with the alternator with the higher regulator setting doing all the work.

I too worry about the AtoB drawing too much power from the small one. It was clear however that when RCR tested the big one with the AtoB out of circuit, there was 14 V from the alternator and less than an amp of current. I will pm you.

[WotEver]

19 minutes ago, Sir Nibble said:

I'm not convinced about any of this. I have no direct experience of this sterling unit but as I understand it isn't it supposed to load both alternators to 13V to ensure max field? According to the voltages on your alternators that's not happening is it. The small Nippon Denso 55A unit is regulated quite high at about 14.6V, the larger Bosch one at around 14.4V. So, the small alternator will be working flat out up to a voltage 0.2V above where the Bosch begins to idle. The big alternator will never have any work to do except when the load demand is above 55A. To test the performance of the big alternator you need to kill the output of the small one by removing the multiplug.

I agree, and this is why I repeatedly suggested disconnecting the smaller alternator from the A2B so that we would be looking at only the larger alternator on its own 

[Sir Nibble]

14V from the alternator is test passed. Current is completely irrelevant. Was the small alternator still connected to the AtoB? If so they are still both connected to the domestics.

[WotEver]

44 minutes ago, Dr Bob said:

I too worry about the AtoB drawing too much power from the small one.

It isn’t a case of ‘drawing power’ from it. It’s simply that once the current drops sufficiently for the alternators’ internal regulators to start working the large alternator shuts down at a lower voltage, leaving the small one to do all the work. 

I was suspicious that this could be the case, which is why I kept asking you to disconnect the 55A alternator. Snib has the figures which confirm that this will happen. 

[Sir Nibble]

What gets me is that the man on the spot condemns an alternator that's making 14V because of low current. What was he expecting to see? Ohms law applies and the only conclusion that can be made is an effective circuit resistance of 14ohms.

[Dr Bob]

57 minutes ago, Sir Nibble said:

What gets me is that the man on the spot condemns an alternator that's making 14V because of low current. What was he expecting to see? Ohms law applies and the only conclusion that can be made is an effective circuit resistance of 14ohms.

Sir Nibble, 10/10. The 90A is fine. 65A out charging with the 55A amp out of circuit. Looks like the Sterling AtoB is pretty useless if you have 2 alternators with different voltage regulators. Doesnt say that in the literature. This must have been going on for 6 months but as I am never lower than 85% SoC, the 55A has only been working over 30A for an hour each day. That will save me a bit of money and we are mobile again.

...cue.....everyone can slag off the Sterling AtoB .....but it was good at getting 14.6V into the domestic to charge it.

[Sir Nibble]

It looks like the AtoB wasn't doing anything to be frank and it's the higher regulator setting on the small alternator that makes the difference. Goes to show that big alternators are no panacea though. I suspect the AtoB is either wrongly installed or faulty.

[WotEver]

7 minutes ago, Sir Nibble said:

I suspect the AtoB is either wrongly installed or faulty.

Even if not, it is uneccessary, as was said before it was purchased and fitted. 

35 minutes ago, Dr Bob said:

Looks like the Sterling AtoB is pretty useless if you have 2 alternators with different voltage regulators. Doesnt say that in the literature.

Of course it doesn’t

It also doesn’t say that with any alternator built in the last 30 years or so the same improvements to the charging circuit can be achieved by having correctly sized cables with quality terminations. 

[WotEver]

42 minutes ago, Dr Bob said:

The 90A is fine. 65A out charging with the 55A amp out of circuit.

See what I suggested 4 days ago...

 

[Sir Nibble]

The thing is that as I understand it the AtoB should load both alternators to 13V to undercut the regulator setting regardless and it isn't doing that. So I do suspect a fault somewhere. Having said that, there must come a point where it either allows the alternators to fall back to their respective regulation or start throwing power away, presumably as heat and I can't see that being the case.

[WotEver]

Just now, Sir Nibble said:

The thing is that as I understand it the AtoB should load both alternators to 13V to undercut the regulator setting regardless

Oh, I wasn’t aware that it did that (or at least that it is supposed to). 

That makes a lot more sense. 

I can’t see how you could install it incorrectly - it’s too simple - so you could well be right that it’s faulty. It appears to be doing nothing more than paralleling the alternators. 

[bizzard]

If you've been running with only the small alternator doing the bulk of the work, I'd chuck the AtoB thing and other gizmos and simply wire up either separately, small alternator to engine battery and the big one to the cabin batteries. Or disconnect the small alternator and remove its drive belt and keep it as an emergency standby. Introduce a either a split charge relay or a VSR instead so that the big alternator does all the work for a change and gives the small one a breather. As I said if the small alternator has been doing the bulk of the work, you'll wonder whats happeed, it will all seem to charge fantastically.

I hope this wasn't too technical for you folks.  An ammendment=  If the small alternator is driven by the same belt as the engines water pump you will need to fit a shorter belt, missing out the small alternator to continue driving the water pump.

Edited April 2, 2018 by bizzard

[WotEver]

37 minutes ago, Sir Nibble said:

The thing is that as I understand it the AtoB should load both alternators to 13V to undercut the regulator setting regardless and it isn't doing that. So I do suspect a fault somewhere. Having said that, there must come a point where it either allows the alternators to fall back to their respective regulation or start throwing power away, presumably as heat and I can't see that being the case.

I’ve just taken a look at the documentation. Reading the description and graphs on page 9 it appears to me that once the charge enters absorption (points 6 & 9 on the graphs) the artificial voltage loading is removed, permitting the alternator’s regulator to take over. At which point it really isn’t doing very much at all other than raising the voltage very slightly. The effect is magnified on the graph by showing an alternator regulated at 14.0V.

If the user never discharges too deeply and hence spends little time in bulk I can’t see that the A2B achieves very much at all.

See page 9:

https://cdn.shopify.com/s/files/1/0658/7343/files/AB12130.pdf?477

Edited April 2, 2018 by WotEver
Added a bit

[bizzard]

6 minutes ago, WotEver said:

I’ve just taken a look at the documentation. Reading the description and graphs on page 9 it appears to me that once the charge enters absorption (points 6 & 9 on the graphs) the artificial voltage loading is removed, permitting the alternator’s regulator to take over. At which point it really isn’t doing very much at all other than raising the voltage very slightly. The effect is magnified on the graph by showing an alternator regulated at 14.0V.

If the user never discharges too deeply and hence spends little time in bulk I can’t see that the A2B achieves very much at all.

See page 9:

https://cdn.shopify.com/s/files/1/0658/7343/files/AB12130.pdf?477

But it is doing something. Its sapping and wasting some electricity. They don't work for nothing.

[Iain_S]

42 minutes ago, Sir Nibble said:

The thing is that as I understand it the AtoB should load both alternators to 13V to undercut the regulator setting regardless and it isn't doing that. So I do suspect a fault somewhere. Having said that, there must come a point where it either allows the alternators to fall back to their respective regulation or start throwing power away, presumably as heat and I can't see that being the case.

But if it does that, and the batteries can't accept the resulting current, what happens to the extra power?