Alternator connection

[Chris_Robb]

Also had pc problems, seems like an epidemic!.

Yes I am staying afloat here for the winter, preping the boat ready for as much as i can, have the Vlhio Club looking after her.

To be honest I did expect better than 28/30amps and 13.8v initially, have checked the alternator feed and it does get warm, it is about 10mm cable overall, I am doing some further checks today, the BATT1, 2 BOTH switches are older type, going to remove and see if they ok and also add another feed cable, not ideal but will certainly cure any resistance.

I am not quite sure what you meant about using long cables with croc clips, my alternator is close enough to do the reading you suggested.
Should I do it with the engine off, or when charging?

As to mixing batteries, we have discussed this at length in another thread, and the concensus is that so long as they are the same type of battery, ie: lead acid, then whether they are 2 x 6v in series or just 1 x 12v does not make any difference.

Getting on with the checks now.

Its just easier to have croc clips on the multimeter than to try to stretch between the battery and alternator. Do it off the alternator when running as the multimeter will be measuring the voltage difference at each end of the main cables

If the cables are getting warm it shows that the volts and therefore amps are being lost here. It made a hell of a difference on mine to double up. Calculation on line here
http://www.solar-wind.co.uk/cable-sizing-DC-cables.html
Remember to measure there and back in the length. Cables are referred to as mm squared, so I dont know how thick you need to go, but you can't go far wrong by just doubling up exactly the same size.

Vliho Yacht Club - Ruari and all are a great bunch. The old ships engineer (Dave??) is very very good on engines. He lives on one of the boats on the quay - or he did 3 years ago. I think others of his people need greater supervision though that might have just been an aberration!

 

[Chris_Robb]

Your Switch - these are pretty reliable if its the big rotary job fitted as standard to the Westerleys. Again, if any connector on the switch is warm, thats loosing amps/volts. Again, you can put your multimeter on either side of the connection and see if there is a voltage drop - with a large current running.

 

[nigelmercier]

... it is about 10mm cable overall [my bold]...

10mm² cable should be Ok for 30 or 40 amps ...

10mm² cable would have an OD between 6.5mm and 7.5mm, so this may be 16mm² or more.

 

[VicS]

10mm² cable would have an OD between 6.5mm and 7.5mm, so this may be 16mm² or more.

Ah!

10mm² thin wall ( low voltage) cable has an overall diameter of 6mm

It's 25mm² thin wall cable that has a an overall diameter of approx 10mm. Its current rating is 170 amps.

Overloaded cable therefore not the OP's problem and replacing with 70 amp cable would be a retrograde step

 

[Chris_Robb]

Ah!

10mm² thin wall ( low voltage) cable has an overall diameter of 6mm

It's 25mm² thin wall cable that has a an overall diameter of approx 10mm. Its current rating is 170 amps.

Overloaded cable therefore not the OP's problem and replacing with 70 amp cable would be a retrograde step

Calculating from the link:
http://www.solar-wind.co.uk/cable-sizing-DC-cables.html
Using 90 amps max current and 5 meters distance there and back to the batteries (distance is very important) this calculates around 50mm2. At 3 meters this drops to 25mm2.

From the tables below are the approx sizes of cable - not much difference between 16 and 35mm so careful measurements - exclude the insulation.
[TABLE="width: 520, align: center"]
[TR]
[TD="align: center"][/TD]
[TD="align: center"]

Nominal Overall Diameter mm​

[/TD]
[TD="align: center"]

Approx Weight Kg/100mt​

[/TD]
[/TR]
[TR]
[TD="align: center"]

16mm2​

[/TD]
[TD="align: center"]

9.1​

[/TD]
[TD="align: center"]

21​

[/TD]
[/TR]
[TR]
[TD="align: center"]

25mm2​

[/TD]
[TD="align: center"]

10.6​

[/TD]
[TD="align: center"]

30​

[/TD]
[/TR]
[TR]
[TD="align: center"]

35mm2​

[/TD]
[TD="align: center"]

11.6​

[/TD]
[TD="align: center"]

40​

[/TD]
[/TR]
[TR]
[TD="align: center"]

50mm2​

[/TD]
[TD="align: center"]

13​

[/TD]
[TD="align: center"]

52​

[/TD]
[/TR]
[TR]
[TD="align: center"]

70mm2​

[/TD]
[TD="align: center"]

14.9​

[/TD]
[TD="align: center"]

73​

[/TD]
[/TR]
[TR]
[TD="align: center"]

95mm2​

[/TD]
[TD="align: center"]

17.2​

[/TD]
[TD="align: center"]

101​

[/TD]
[/TR]
[TR]
[TD="align: center"]

120mm2​

[/TD]
[TD="align: center"]

19.6​

[/TD]
[TD="align: center"]

123​

[/TD]
[/TR]
[TR]
[TD="align: center"]

150mm2​

[/TD]
[TD="align: center"]

21.3​

[/TD]
[TD="align: center"]

152​

[/TD]
[/TR]
[TR]
[TD="align: center"]

185mm2​

[/TD]
[TD="align: center"]

23.5​

[/TD]
[TD="align: center"]

189​

[/TD]
[/TR]
[TR]
[TD="align: center"]

240mm2​

[/TD]
[TD="align: center"]

26.6​

[/TD]
[TD="align: center"]

246​

[/TD]
[/TR]
[TR]
[TD="align: center"]

300mm2​

[/TD]
[TD="align: center"]

29.4​

[/TD]
[TD="align: center"]

306​

[/TD]
[/TR]
[TR]
[TD="align: center"]

400mm2​

[/TD]
[TD="align: center"]

33.3​

[/TD]
[TD="align: center"]

386​

[/TD]
[/TR]
[TR]
[TD="align: center"]

500mm2​

[/TD]
[TD="align: center"]

37​

[/TD]
[TD="align: center"]

491​

[/TD]
[/TR]
[TR]
[TD="align: center"]

630mm2​

[/TD]
[TD="align: center"]

41.4​

[/TD]
[TD="align: center"]

635​

[/TD]
[/TR]
[/TABLE]

The amps are going somewhere. Lets see what the doubling up actually does.

Some info on the Prestolite inbuilt regulator:
They are factory set to 14.4 and output this continuously (ie they are not a 3 stage like the Balmar). They can be user adjusted for other voltages. They are temperature adjusted (on the alternator). The Prestolite 110 amp that I bought from Adverc was regulated at 13.8V being designed to be used with their alternator controller. I have mine connected with a Sterling unit set to 14.4V. If the batteries are well discharged it will generate 80 amps to start with and then tail off. They float at 13.8V. The Sterling (or any controller) cannot reduce below the alternator output.

Question - is it harmful to batteries when on a 24/48 hour motoring trip that you run them at 14.4v continuously?

 

[Sarnia]

Its just easier to have croc clips on the multimeter than to try to stretch between the battery and alternator. Do it off the alternator when running as the multimeter will be measuring the voltage difference at each end of the main cables

If the cables are getting warm it shows that the volts and therefore amps are being lost here. It made a hell of a difference on mine to double up. Calculation on line here
http://www.solar-wind.co.uk/cable-sizing-DC-cables.html
Remember to measure there and back in the length. Cables are referred to as mm squared, so I dont know how thick you need to go, but you can't go far wrong by just doubling up exactly the same size.

Vliho Yacht Club - Ruari and all are a great bunch. The old ships engineer (Dave??) is very very good on engines. He lives on one of the boats on the quay - or he did 3 years ago. I think others of his people need greater supervision though that might have just been an aberration!

I have doubled up the alternator feed, now 2 x 10mm2 also suspect the BATT 1, 2 switches, they have been on the boat from build, 40 years, looking for a new integrated one. Already had much improved amps.
Ruari and Vicky have a great team now, a professional set up, not sure about Dave, he doesn't seem to be here now.

 

[Sarnia]

Ah!

10mm² thin wall ( low voltage) cable has an overall diameter of 6mm

It's 25mm² thin wall cable that has a an overall diameter of approx 10mm. Its current rating is 170 amps.

Overloaded cable therefore not the OP's problem and replacing with 70 amp cable would be a retrograde step

Have purchased and fitted a new BATT 1, 2 BOTH rotary switch, to replace the old two switches originally fitted, which were suspect having been there from build, god knows how many switchings they have had, immediate increase in voltage from 13.8 to 14.2, and that is with batteries at 65% with 32 amps charge showing, in addition to doubleing the alternator feed cable, now 2 x 10mm, also replaced much of the cable to it from batteries with 35mm super flexible, going to do the same with the negative side also.
The odd thing is that my engine ammeter which was previously reading 50 amps, at a low battery condition, is now hardly moving at all, this is since I modified the wiring as I sent to you, the BM-1 shows charging and loads as it should.

 

[VicS]

Have purchased and fitted a new BATT 1, 2 BOTH rotary switch, to replace the old two switches originally fitted, which were suspect having been there from build, god knows how many switchings they have had, immediate increase in voltage from 13.8 to 14.2, and that is with batteries at 65% with 32 amps charge showing, in addition to doubleing the alternator feed cable, now 2 x 10mm, also replaced much of the cable to it from batteries with 35mm super flexible, going to do the same with the negative side also.
The odd thing is that my engine ammeter which was previously reading 50 amps, at a low battery condition, is now hardly moving at all, this is since I modified the wiring as I sent to you, the BM-1 shows charging and loads as it should.

Really need to see diagrams of the switching .... I am puzzled by the fact that you appear to have replaced two 1, 2, both switches with just one new one.

Also need a diagram that shows how the engine ammeter is connected .......... Just a thought, have you by passed it with your doubled up wiring ?

 

[Sarnia]

Really need to see diagrams of the switching .... I am puzzled by the fact that you appear to have replaced two 1, 2, both switches with just one new one.

Also need a diagram that shows how the engine ammeter is connected .......... Just a thought, have you by passed it with your doubled up wiring ?

The old switching was two switches, commoned together with a copper bar on top connections, to which the feed to the starter and feed from the alternator was also connected.
The bottom connections of each, one had domestic battery and the other the starter battery positives.
The new switch, a GUEST, made in the US, either made by MARINCO or supplied by them, a substantial bit of kit.
It has three heavy connections, BATT1 BATT2 and FEED, which is the same as my old setup, the FEED does what the bar did on the old installation.
Yesterday I connected it up, the switch not mounted but hanging in the wiring, and it worked well.
Today i did the work to mount the switch, needed holes drilled through the panel it is mounted on, re-route cables a little etc to make a neat job.
When i started engine I was back to 13.5v although amps good with battery at 60%, I have rechecked the wiring and it is correct as previous, but enough for today working on my back under the chart table!
I will send you the diagrams which you asked for, and do further checks tomorrow.
Here is the link for the switch: www.marinco.com/en/~/media/inriver/317638-11622.pdf

 

[Chris_Robb]

Have purchased and fitted a new BATT 1, 2 BOTH rotary switch, to replace the old two switches originally fitted, which were suspect having been there from build, god knows how many switchings they have had, immediate increase in voltage from 13.8 to 14.2, and that is with batteries at 65% with 32 amps charge showing, in addition to doubleing the alternator feed cable, now 2 x 10mm, also replaced much of the cable to it from batteries with 35mm super flexible, going to do the same with the negative side also.
The odd thing is that my engine ammeter which was previously reading 50 amps, at a low battery condition, is now hardly moving at all, this is since I modified the wiring as I sent to you, the BM-1 shows charging and loads as it should.

Just for clarification: You have only doubled up the Positive feed and not the negative? If so, you have seen 50% of the improvement only, so more to come I hope.

When quantifying the finished product, it would be useful to note amps ver voltage at start up , and every 15 minutes, seeing he progressing rise in volts and drop in amps. This will give you a good base line for future charging giving you a good idea of the state of charge. I never use the BM1 % charge as it is pretty misleading.

 

[Sarnia]

Just for clarification: You have only doubled up the Positive feed and not the negative? If so, you have seen 50% of the improvement only, so more to come I hope.

When quantifying the finished product, it would be useful to note amps ver voltage at start up , and every 15 minutes, seeing he progressing rise in volts and drop in amps. This will give you a good base line for future charging giving you a good idea of the state of charge. I never use the BM1 % charge as it is pretty misleading.

Today i have also replaced the negative side from the alternator, two new leads virtually doubled the old one, all nice and clean and tight.

I have also explored where the feed from the alternator goes to, previously I followed the loom and saw a cable the same size going to the feed busbar on the old switches, did a continuity check with both ends disconnected to prove it, so I ran the new feed to the same place, doubling the capacity.
Today when re-clipping the cables back I can see that it doesn't go where I expected, even though I had a continuity check, it goes into another loom heading over to the engine control panel area, I have not took that out as its a bit of a job getting to it, but the efeects were the same, the only difference now is that the engine ammeter hardly reads at all, the BM-1 does though, have I possibly side tracked the engine ammeter with the second feed direct to the battery via the 3 way switch?
The new switch works perfectly, the readings today after the rewire was 40 amps, 13.8v, the reading, volt drop, between the alternator feed and the battery pos was 0.12v. As thr battery charged the volts went up to 14.1v as the amps dropped to 20 then 15 over half an hour.
I do not really mworry about the engine ammeter reading, my BM-1 is what I depend on.
Here in Vlhio we have had two days of thunder and lightening and torrential rain, all cosy inside though.

 

[Chris_Robb]

Today i have also replaced the negative side from the alternator, two new leads virtually doubled the old one, all nice and clean and tight.

I have also explored where the feed from the alternator goes to, previously I followed the loom and saw a cable the same size going to the feed busbar on the old switches, did a continuity check with both ends disconnected to prove it, so I ran the new feed to the same place, doubling the capacity.
Today when re-clipping the cables back I can see that it doesn't go where I expected, even though I had a continuity check, it goes into another loom heading over to the engine control panel area, I have not took that out as its a bit of a job getting to it, but the efeects were the same, the only difference now is that the engine ammeter hardly reads at all, the BM-1 does though, have I possibly side tracked the engine ammeter with the second feed direct to the battery via the 3 way switch?
The new switch works perfectly, the readings today after the rewire was 40 amps, 13.8v, the reading, volt drop, between the alternator feed and the battery pos was 0.12v. As thr battery charged the volts went up to 14.1v as the amps dropped to 20 then 15 over half an hour.
I do not really mworry about the engine ammeter reading, my BM-1 is what I depend on.
Here in Vlhio we have had two days of thunder and lightening and torrential rain, all cosy inside though.

Agreed that you have probably bypassed the ameter. I wouldn't worry as the BM1 is the one you want. However you do need to work out the wiring just to be sure.

Charging - Rising to 14.1V. You need to do an extended test as you should be able to get the voltage up to 14.4V. It may be that you are a candidate for an alternator booster such as the Sterling or Adverc, but this will require you putting a field control wire on the alternator.

As a comparison my alternator (Prestolite 110Amp) starts at about 80 amps 13.8, rising very quickly to 14.4V and dropping to 60Amps then tailing off at 14.4 to about 25 amps and eventually the sterling drops it to 13.8v when the charge drops off to anything from 2 or 3 amps to 8A. The Alternator is set to 13.8 by Adverc who modified it for their own controller (- but works in the same way as the Sterling) - so allowing the alternator to float charge the batteries. An alternator charge controller cannot reduce the charge below that set on the alternator regulator itself.

I have not experienced an alternator set at 14.4V running for hours on end and what it might do to the batteries. Your prestolite has a simple regulator which will not run below its setting, however it is adjustable.

You really need to see your voltages rise to 14.4V quite quickly as there is a significant difference in the charge rate at 14.1 (of course better than 13.8!). So if you want perfection you may need to think wider on the final solution.

I am not an electrician, but have learnt bits over the years often by bitter experience! Others may be able to enlighten you on this on the benefit of a charge controller.

I

 

[nigelmercier]

... I followed the loom and saw a cable the same size going to the feed busbar on the old switches, did a continuity check with both ends disconnected to prove it ...

Never rely on a continuity test to check that two apparent ends of cable are continuous. When a cable passes through an opening, I make a ring out of paper and sticky tape, then push it along the cable until it emerges the other side.

 

[Sarnia]

Never rely on a continuity test to check that two apparent ends of cable are continuous. When a cable passes through an opening, I make a ring out of paper and sticky tape, then push it along the cable until it emerges the other side.

Good idea, will use it in the future, thanks.

 

[Sarnia]

Agreed that you have probably bypassed the ameter. I wouldn't worry as the BM1 is the one you want. However you do need to work out the wiring just to be sure.

Charging - Rising to 14.1V. You need to do an extended test as you should be able to get the voltage up to 14.4V. It may be that you are a candidate for an alternator booster such as the Sterling or Adverc, but this will require you putting a field control wire on the alternator.

As a comparison my alternator (Prestolite 110Amp) starts at about 80 amps 13.8, rising very quickly to 14.4V and dropping to 60Amps then tailing off at 14.4 to about 25 amps and eventually the sterling drops it to 13.8v when the charge drops off to anything from 2 or 3 amps to 8A. The Alternator is set to 13.8 by Adverc who modified it for their own controller (- but works in the same way as the Sterling) - so allowing the alternator to float charge the batteries. An alternator charge controller cannot reduce the charge below that set on the alternator regulator itself.

I have not experienced an alternator set at 14.4V running for hours on end and what it might do to the batteries. Your prestolite has a simple regulator which will not run below its setting, however it is adjustable.

You really need to see your voltages rise to 14.4V quite quickly as there is a significant difference in the charge rate at 14.1 (of course better than 13.8!). So if you want perfection you may need to think wider on the final solution.

I am not an electrician, but have learnt bits over the years often by bitter experience! Others may be able to enlighten you on this on the benefit of a charge controller.

I

The reasoning behind buying a modern alternator was to avoid installing a sterling/adverc controller, this was comprehensively discussed here in a previous thread, the majority opinion being that modern alternators reach 14.4 and make controllers redundant, or at least unnessasary, it was that point of view i have followed to install a prestolite.
I believe the model I have installed does not have an adjustable regulator, certainly the makers spec says not, would be better if it did as I would have selected one that has, but the physical dimensions I needed to fit my engine reduced the selection somewhat.
I am not to concerned re the engine ammeter, as you point out the BM-1 is what I depend on.
Many thanks for your help, maybe we will meet up somewhere in Greece.

 

[Chris_Robb]

The reasoning behind buying a modern alternator was to avoid installing a sterling/adverc controller, this was comprehensively discussed here in a previous thread, the majority opinion being that modern alternators reach 14.4 and make controllers redundant, or at least unnessasary, it was that point of view i have followed to install a prestolite.
I believe the model I have installed does not have an adjustable regulator, certainly the makers spec says not, would be better if it did as I would have selected one that has, but the physical dimensions I needed to fit my engine reduced the selection somewhat.
I am not to concerned re the engine ammeter, as you point out the BM-1 is what I depend on.
Many thanks for your help, maybe we will meet up somewhere in Greece.

I must have missed that thread, as I have always been concerned, rightly or wrongly, that charging batteries continuously once charged at 14.4V might be harmful in the long term, hence why I installed a sterling so that it would float charge when fully charged.

Anyway - you are where you are, and now the main thing is to get your voltage at the batteries to reach 14.4V ie the same as the voltage off the back of the alternator. You can always add a controller later if you need to.

Give my regards to Ruari and Vicky (I can never spell it).

 

[pvb]

I must have missed that thread, as I have always been concerned, rightly or wrongly, that charging batteries continuously once charged at 14.4V might be harmful in the long term, hence why I installed a sterling so that it would float charge when fully charged.

Worth mentioning again that, when installed according to the instructions (ie in parallel with the alternator's own regulator), the Sterling Alternator Regulator can only increase the output voltage. It can't decrease it below the setting of the alternator's own regulator. So a true float voltage will normally not be achieved.

 

[Chris_Robb]

Worth mentioning again that, when installed according to the instructions (ie in parallel with the alternator's own regulator), the Sterling Alternator Regulator can only increase the output voltage. It can't decrease it below the setting of the alternator's own regulator. So a true float voltage will normally not be achieved.

Ah, but Adverc has set the Prestolite to 13.8V so it can float.

 

[pvb]

Ah, but Adverc has set the Prestolite to 13.8V so it can float.

That's fine. Most people don't have adjustable regulators though, and believe the Sterling hype.

 

[nigelmercier]

... Most people don't have adjustable regulators though...

It has only recently occurred to me that this is the case. Some people are quite happy to send poorly regulated charge voltages to their very expensive battery bank. I guess I'm lucky that I bought the boat with a Balmar MaxCharge regulator, but if I didn't have one already, it would be top of my list.