alternator issues battereisnot charging!

[imranino]

Hello all,

 

I've search the forums to the best of my abiities but I can't fing any answers...

 

Here's my setup:

Alternator goes to battery bank (2x110 leisure and 1 starter via relay) via a sterling 4-step alternator booster (the old fashioned yellow box type).

 

The batteries are hardly getting a charge as they're receiving about 13v. The alternator is sending 16v and of course the high voltage trip light is lit up on the sterling unit.

 

What I've done so far is replace the alternator regulator to no avail.

 

What do you think the source of the probem is? I get a sense it's either the alternator or the wiring. I don't see how it could be the latter as the batteries have charged in the past at 14v (according to the dashboard).

 

Since living on a boat for just over a year, this is the first time I'm had to work with the batteries,and the first time I've even touched the alterator.

 

Here's what I could do:

 

1 - take the alternator out and get it tested/serviced at a garage and if it's dead get a new one.

 

2 - run some further tests based on the vast wisdom available here

 

3 - be told by you guys that I'm in over my head and should get a pro to come have a look (I won't be offended!)

 

Thanks!

[BEngo]

If the alternator is doing 16 V it's probably OK and it has a new regulator then I expect it's being over driven by the Sterling or a fault in the Sterling wiring.

 

What sort of Alternator is it?

 

Step 1 Check all the joints and connections between the alternator and the battery particularly round the relay. Fix as required and re-test. If not then OK

Step 2 Disable the sterling box- disconnect its power wire and the wire to the alternator regulator.

Step 3 Start engine. Tell us what the voltages are at the alternator, the relay input, relay output and both batteries.

 

N

[Tony Brooks]

I agree with Bengo.

 

If the alternator is delivering 16 volts then as long as the relay is really a relay then one of the batteries should be getting very close to 16 volts. If , as you imply, both are at 13 volts then something is causing voltdrop. It could be a connection, a terminal loose on the conductor or, if the system has been wired in the optimum way, a faulty domestic master switch. In the latter case especially if your domestic loads are normally low.

[Arthur Brown]

Check for corrosion at contacts, and at the master switch. If you have 16v at the alternator and 13v at the batteries then those three volts are being lost somewhere and can likely be found with a multimeter.

[Sir Nibble]

Check for corrosion at contacts, and at the master switch. If you have 16v at the alternator and 13v at the batteries then those three volts are being lost somewhere and can likely be found with a multimeter.

That's the bunny! The reason you have such a high alternator voltage is because the sterling unit is trying to regulate on the voltage actually arriving at the batteries. You may find the poor connection by very carefully visually inspecting for signs of heat. This is not actually more than a pretty minor fault finding job and if you let us know where you are there is a fair chance an electrically competent forum member could pop along and nail the problem in 10 minutes.