Fridges

[Guest]

1 hour ago, Tony Brooks said:

Ok. That rules out the relay contacts.

 

Now do WotEver's test but I would say at 1200 to 1500 rpm to make sure the alternator is running at high output and I emphasize when WotEver said battery post he meant the LEAD post, NOT the clamp/terminal. Push the meter probe into the lead.

 

While you are at it repeat between the alternator case and the lead of the negative terminal. One hopes for an even lower reading but if not there is a poor negative connection somewhere.

If I'm doing it correctly: revs 1500, multimeter DC 20, one lead on alternator case other onto neg lead of alternator, reading 009 - 10, 

[Guest]

Is that the one that goes to the starter solenoid

[Guest]

8 minutes ago, oats said:

Is that the one that goes to the starter solenoid

Seen it thanks my mistake again don't think it goes to solenoid 'thick or what'

[Guest]

3 hours ago, WotEver said:

Great. Another check, with the engine running at a fast idle and again with discharged batteries (so in the morning), would be to put one multimeter lead on the positive post of the battery and the other on the main (B+) alternator output. Again it should read a very low figure. If it reads half a volt or more then you either have a very poor connection somewhere or severely undersized cabling. Hopefully it’ll only show 0.1V or so. 

Hi just checked your suggestion, my batteries at 12.2. Connected multimeter engine 1500 showed 0.8 

Just now, oats said:

Hi just checked your suggestion, my batteries at 12.2. Connected multimeter engine 1500 showed 0.8 

With my update to Tony and your reply should I now look at checking all earth's or positives? Or both to make sure cheers

[Guest]

25 minutes ago, oats said:

Hi just checked your suggestion, my batteries at 12.2. Connected multimeter engine 1500 showed 

Just found loose bolts on back of main switch 

[OldGoat]

25 minutes ago, oats said:

Just found loose bolts on back of main switch 

Hehe - getting there!!

You'll be an expert next.

[Tony Brooks]

1 hour ago, oats said:

If I'm doing it correctly: revs 1500, multimeter DC 20, one lead on alternator case other onto neg lead of alternator, reading 009 - 10, 

 

Those readings make no sense to me. 0.09 and 1.0 or 0.10 would make more sense. The other point is that I can't see a negative lead on your alternator so assume its an earth return one where the negatives go through the engine.

 

I said alternator case (being the alternator negative as far as I can see) to a negative battery lead post. That checks the whole negative caring circuit.

 

15 minutes ago, oats said:

Just found loose bolts on back of main switch 

 

Do you mean battery isolator switch? I note you say switch singular. Are there one or two main battery switches? If one then then its in the negative side of the circuits and it SHOULD have cause poor starting rather more than just poor charging. If it is just one switch it is not the best arrangement but as hundreds of boats are like that do not worry about it.

 

If its two switches then I hope the loose connections are on the domestic battery one. Not only would that cause charging volt drop but it would nt have helped the fridge at all.

 

1 hour ago, oats said:

Is that the one that goes to the starter solenoid

If a wire runs from the alternator to the LARGE terminal on the starter solenoid its the man charging positive lead the thick brown & yellow one in the photo). The alternator end of that cable is where you put one probe of the voltmeter to do WotEver's check.

 

You need to take care because an idiot has wired yor main output to the 9mm blade rather than the B+ stud that I THINK I can see to the rigth and slightly below the wires - check what is cast into the case close by. There is another 9mm blade you may be able to get your probe on close to the one the wire is on.

 

Using the single 9mm blade is just asking for volt drop on the charging circuit.

3 minutes ago, OldGoat said:

Hehe - getting there!!

You'll be an expert next.

 

Absolutely and     learning a lot ready for next time.

[WotEver]

So to summarise, two checks to make with the engine running fast-ish and charging low batteries (might have to be tomorrow morning now):

 

1. From the alternator end of the brown/yellow wire to the battery +ve terminal. 

 

2. From the alternator case to the battery -ve terminal. 

 

** Note where the decimal point is when reporting the readings. **

[ditchcrawler]

4 hours ago, Tony Brooks said:

Ok. That rules out the relay contacts.

 

Now do WotEver's test but I would say at 1200 to 1500 rpm to make sure the alternator is running at high output and I emphasize when WotEver said battery post he meant the LEAD post, NOT the clamp/terminal. Push the meter probe into the lead.

 

While you are at it repeat between the alternator case and the lead of the negative terminal. One hopes for an even lower reading but if not there is a poor negative connection somewhere.

Isn't his alternator an isolated return model with a negative terminal or am I on the wrong thread?

 

[Tony Brooks]

Have a look at the image in post 77

 

There is a heavy black wire but it looks to me as if it terminates on one of the mounting bolts. There is something immediately to the left that I cant identify but it looks like a 9mm female push on connector but there are normally no such blades in that area.

 

In any case I have often found that despite having a B- stud the case is still negative so by checking case to battery negative you are testing at least one internal alternator connection. If it is insulated return he should get a zero volt reading unless there is an engine earth fault.

[Guest]

Morning all, i put a post on here yesterday but cant see it. yes its a single switch that turns everything off, not what i prefer but it works. Update: all seemed ok yesterday, started up this morning: did all the checks as suggested: alternator to - = .01, charging at 13.9 on multimeter, only been running half hour, starter battery 13.3 domestic 13.1. Volt meter on engine panel showing just over 13v, first time its done that, also amp meter is registering again first time. I replaced the ' thin wire' from alternator to relay as i pictures & connected the wire to charge lamp correctly. Cleaned & tightened all wire connections, replaced spade connectors on some as very poor fitted. Think now you all have helped to solve my problems. 

 A BIG thank you to you all & for your patience with the old man. I hope this could help anyone else out as well. CHEERS.

[LadyG]

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Edited May 8, 2020 by LadyG