No charging amps from Alternator.

[Ex- Member]

Hi all, could really do with some help here.

 

We have 2 alts, a 50 amp for engine battery - a 70amp for leisure. The 50 amp charger is fine and was putting out 42 amps on my new amp tester.

 

The 70 amp alt for leisure bank puts out 0 amps I had a feeling we weren't charging when cruising as the volt meter didn't record a voltage increase as did the engine battery, but the engine panel dial also reads nearly 14v when engine running. There's also a Sterling Charge controller connected which basically states high charge rate.

 

The alternator i think is a Bosch with this number on the regulator. 1197311026 EL 14v 4C Cant find anything on the actual alternator.

 

I'm using a new amp meter tester which is a ISO-TECH ICM 36R

 

It's a bit annoying having cruised a fair bit and not got any charge from doing so LOL

 

 

Edited October 1, 2013 by Julynian

[Ex- Member]

Hi all, could really do with some help here.

 

We have 2 alts, a 50 amp for engine battery - a 70amp for leisure. The 50 amp charger is fine and was putting out 42 amps on my new amp tester.

 

The 70 amp alt for leisure bank puts out 0 amps I had a feeling we weren't charging when cruising as the volt meter didn't record a voltage increase as did the engine battery, but the engine panel dial also reads nearly 14v when engine running. There's also a Sterling Charge controller connected which basically states high charge rate.

 

The alternator i think is a Bosch with this number on the regulator. 1197311026 EL 14v 4C Cant find anything on the actual alternator.

 

I'm using a new amp meter tester which is a ISO-TECH ICM 36R

 

It's a bit annoying having cruised a fair bit and not got any charge from doing so LOL

 

Edited: Threads merged - (G&F)

Edited October 1, 2013 by Grace & Favour

[Tony Brooks]

You need to start at the beginning.

 

Confirm no increase in voltage by putting the voltmeter between the main output terminal (B+) and negative (B-) or metal body depending upon design. The start and rev the engine to at least 1500 rpm to check for a rise in voltage. My guess is there will not be one. If there is then starts looking at where leads go into terminals, connections and the master switch.

 

If no rise in voltage run a cable from the domestic battery pos. to the warning lamp terminal on the alternator (D+, ind, w/l etc.) and repeat the above. If it starts to charge then there is something wrong with the excitation/warning lamp circuit. Possible a faulty relay or poor wiring practises.

 

If there is no rise in voltage I would take it off and to a specialist for testing and repair.

 

Note:- a few alternators, but not Bosch ones as far as I know, do not use the warning lamp to excite the alternator.

 

I am assuming there is enough charge in the domestic bank to run the lights, pump etc.

[Tony Brooks]

See my answer in your other thread.

 

IF there is no charge you may want to remove the two cross head machine screws that hold the black disk onto the body. Then you can carefully lift the regulator brush assembly out in case the brushes have worn out. However when they do often the slip rings are so scored that fitting a new assembly only cures the problem for a limited time - how long I can not say, but probably a year plus.

 

I also note that you have non-standard wiring wrapped in spirwrap going into the alternator. I assume this is for an advanced controller . It should not be a phase tap for a revcounter because you have a W terminal.

 

You also have two thin wires on the warning lamp connection. If the non-warning lamp wire has a short on it then that may well stop the alternator charging so take the extra one off (the one that does not put the warning lamp out when you take it off) and try again. On a twin alternator boat it is unlikely to be driving a split charge relay (unless someone is parallelling the alternators for more charge during the first phase of charging) so it could be for an hour counter or some such.

[Ex- Member]

You need to start at the beginning.

 

Confirm no increase in voltage by putting the voltmeter between the main output terminal (B+) and negative (B-) or metal body depending upon design. The start and rev the engine to at least 1500 rpm to check for a rise in voltage. My guess is there will not be one. If there is then starts looking at where leads go into terminals, connections and the master switch.

 

If no rise in voltage run a cable from the domestic battery pos. to the warning lamp terminal on the alternator (D+, ind, w/l etc.) and repeat the above. If it starts to charge then there is something wrong with the excitation/warning lamp circuit. Possible a faulty relay or poor wiring practises.

 

If there is no rise in voltage I would take it off and to a specialist for testing and repair.

 

Note:- a few alternators, but not Bosch ones as far as I know, do not use the warning lamp to excite the alternator.

 

I am assuming there is enough charge in the domestic bank to run the lights, pump etc.

 

Hi Tony

 

Brilliant thanks I'll do those tests now. There is charge in the BB although low around 12.1v as we've had 2 dull days and solar is only putting in 3/4 amps.

 

I noted an e-bayer who will recondition, collect & deliver alternators for £90 100% feedback too.

 

Quite handy really as buying a new alt, if you don't get the same model with same pulley then you end up spending money on changing pulleys or different belts. Just a thought.

 

Anyway I'll do the tests.

 

Thanks so much, really helpful

[Ex- Member]

Ok Tests completed. You're spot on I ran a lead from battery positive to alternator warning lamp, pre set up the amp meter and bingo 74 amps flowing and leisure bank volts meter reading 13.87v also confirmed by a multimeter.

 

So clearly an excitation/warning lamp circuit problem. I'll remove the engine panel and take a look, it's a bit of a squeeze in there and I had cause to remove it a few weeks ago so might have dislodged something when replacing it.

 

Can I use that test wire in the meantime and do I keep it connected if so? ( I mean connected whilst running)

 

Thanks Tony, you're a star, hopefully I'll get to buy you a couple of beers sometime.

Edited October 1, 2013 by Julynian

[pistnbroke]

A wire from the B+ to the WL terminal will put all the alternator output via the field diodes and bugggger them ...you should have put a 5w bulb from B+ to WL to substitute a known good excitation circuit...Even if you burnt out the diodes it will still charge with the wire in place........

[Ex- Member]

A wire from the B+ to the WL terminal will put all the alternator output via the field diodes and bugggger them ...you should have put a 5w bulb from B+ to WL to substitute a known good excitation circuit...Even if you burnt out the diodes it will still charge with the wire in place........

 

Hi PB where are these diodes btw, we don't use any kind of diodes for paralel alternator charging, are you referring to diodes internally in the alternator.

 

I've left the engine running. The BB reached the lowest it's ever been and went down to 11.9v

 

Been running a good 30 minutes and still putting in 62.9 amps with engine @ 1000rpm. I do love this new ammeter clamp gadget LOL brilliant tool.

 

Another thing I would like to ask. I took a reading from each of the 3 cables leading from the battery switch to the BB (Photo below)

 

Each cable read between 21.8 and 22 amps. Am I right in assuming this is an equal distribution from the charge reading from the main alternator lead at 62.9 amps?

 

 

ETA. I've also just noticed that the excitation for the leisure battery alternator was actually taken from the engine battery alternator via the Red lead with Yellow tag. I'm guessing this was done so both the alternator would kick in even if the Leisure bank didn't have sufficient volts to supply interdependently.

 

This is clearly not now working for some reason, even though the engine battery alternator is charging perfectly. Maybe I'll just put in a wire from the BB post to the lamp connection on the alternator.

Edited October 1, 2013 by Julynian

[Tony Brooks]

Not ideal but that method of excitation should work providing the warning lamp is passing sufficient current or or one alternator energises. No idea why it did not.

 

Is your warning lamp a push in black plastic "tube" with a chrome bezel around a coloured lens? If so see if it has a replaceable bulb. If not its a grain of wheat bulb and they do not pass sufficient current to energise many alternators. If its a removable bulb its probably only 1.5 watts which will usually energise one alternator but probably not two. I would want 2.2 watts at least for two,4 or 5 watts would be better.

 

Far better still is to have a second warning lamp fed from the domestic battery via a relay contacts. The relay being energised by a feed from the ignition on terminal of the existing switch. Then you will know if an alternator fails.

 

I totally disagree with Pistnbroke. One of the tests I told you to do would pretty much ensure there was continuity on the main charging leads so any current flowing in the temporary lead once charging commences will be only what can flow with the difference in voltdrop on the main charging lead and the temporary lead. Seeing the D+/ W/L terminal usually runs a slightly lower voltage than the main B+ terminal there may not actually be a difference. However I do agree with him that if you want to make this permanent you need to put a warning lamp in the wire.

[Ex- Member]

Not ideal but that method of excitation should work providing the warning lamp is passing sufficient current or or one alternator energises. No idea why it did not.

 

Is your warning lamp a push in black plastic "tube" with a chrome bezel around a coloured lens? If so see if it has a replaceable bulb. If not its a grain of wheat bulb and they do not pass sufficient current to energise many alternators. If its a removable bulb its probably only 1.5 watts which will usually energise one alternator but probably not two. I would want 2.2 watts at least for two,4 or 5 watts would be better.

 

Far better still is to have a second warning lamp fed from the domestic battery via a relay contacts. The relay being energised by a feed from the ignition on terminal of the existing switch. Then you will know if an alternator fails.

 

I totally disagree with Pistnbroke. One of the tests I told you to do would pretty much ensure there was continuity on the main charging leads so any current flowing in the temporary lead once charging commences will be only what can flow with the difference in voltdrop on the main charging lead and the temporary lead. Seeing the D+/ W/L terminal usually runs a slightly lower voltage than the main B+ terminal there may not actually be a difference. However I do agree with him that if you want to make this permanent you need to put a warning lamp in the wire.

Hi tony

 

 

(Is your warning lamp a push in black plastic "tube" with a chrome bezel around a coloured lens? ) No just a small Red lens with chrome ring surround.

 

( I would want 2.2 watts at least for two,4 or 5 watts would be better.) Ok Tony I'll check this out.

 

Well what ever regarding the last paragraph it diagnosed the problem, I certainly wouldn't have had a clue LOL

 

I ran the engine for 1.5 hours. I was surprised that the amps going into the batteries remained at 60 amps or over for all that period initially kicking off at 74 amps. After running engine and switching off, and the bank settling for an hour the bank voltage leveled off at 12.47v and that's with inverter & fridge on. As mentioned the bank went down to 11.9v so was well under 50% SOC

 

I would mention though these clamp testers don't seem to be uber accurate as a test on the solar input cable to batteries showed the Outback stating 3.7 amps and the tester 3.2

Very low amps I suppose, I have 2 amp settings 200 and 600, of course I was on the 200 LOL

 

Anyway all this set up worked previously, so something has changed somewhere. Hopefully the bulb wattage might solve the problem and all can be wired as it was originally.

 

Thanks again Tony much appreciated.