Batteries not charging properly

westhinder

westhinder

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My new to me boat has a Sterling booster, but the batteries do not seem to receive more than 13.2 volts with the engine doing 2500 rpm. On the booster two LEDs are illuminated: both for boost charge and float charge. The warning lights are off.
When plugged in the mains, the battery charger does provide 14.2 volts, as I would expect.

Any ideas what might be wrong?
 
One of the "Digital Advanced Alternator Regulators" ?

Check that it is wired correctly .. you can download the instructions from the website if you do not have them.

It might be a good idea to disconnect it and make sure that the alternator is performing correctly without it.


If there is no information in the instructions that indicates what the problem is ring Sterling ........ but dont do so until you are sure the answer is not in the instructions
 
The alternator was removed for reconditioning in the winter and re-installed by a technician. I assumed it was wired correctly, but am now having my doubts.
 
westhinder said:
The alternator was removed for reconditioning in the winter and re-installed by a technician. I assumed it was wired correctly, but am now having my doubts.
Click to expand...
Did you get back the same alternator? Remember that the regulator in the alternator has to be rewired to use the Advanced Regulator. They may have seen the rewiring as a 'fault'. Just a thought.

Have you checked the voltages in and out of the alternator and regulator?

Once you've checked that then phone Sterling. You'll probably speak to Charles (main man) and he has always been very helpful to me on the four or five times I've called for help or just advice.
 
westhinder said:
The alternator was removed for reconditioning in the winter and re-installed by a technician. I assumed it was wired correctly, but am now having my doubts.
Click to expand...

If the alternator has been reconditioned, its possible that they have not done the extra wiring needed by the Sterling regulator or it is not in circuit.

The basics of how it works are simple. The Sterling regulator looks at the voltage at the batteries ( so there should be a wire from the Sterling to the batteries or at least picking up the battery voltage at the engine end of the thick starter positive feed). It then decides what output voltage from the alternator is required and it feeds in the necessary exciter voltage to the alternator brushes.

There should be an extra non standard wire appearing out of the back of the alternator ( its connected to the brushes) and this goes to the sterling regulator. From memory I believe its the yellow Sterling wire that this connects to but you can check from the link above.

Clearly your Sterling is connected into the system or the lights would not be lit but it could be that it is missing the battery sensing wire or more likely the extra wire to the brushes. If it were working properly, then the voltage at the batteries should be 14.8 for vented lead acid cells and 14.4 for sealed lead acid to start with but it drops back to a float voltage when it decides things are fully charged. Cant remember the float figure but it will be around 13.7.

Have a look round yourself. The system is easy to understand if you take it step by step. It isnt high tech at all. Check that there is an extra wire out the back of the alternator coupled to the Sterling yellow and that the battery sensing wire from the Sterling is connected. There are other issues that it could be, but these are the most likely.

As it happens I had my alternator checked yesterday by a techie and despite me telling him that it was an isolated earth he insisted on checking with the negative to the frame and then telling nme the alternator was duff when it wasnt. So there is no guarantee that your techie is any good or just sloppy. Sad but thats the UK these days.
 
Thanks folks, I will check as suggested in the weekend. Electricity remains a bit of dark art to me, so I hope I can make sense of it all.
 
wotayottie said:
If it were working properly, then the voltage at the batteries should be 14.8 for vented lead acid cells and 14.4 for sealed lead acid to start with but it drops back to a float voltage when it decides things are fully charged. Cant remember the float figure but it will be around 13.7.
Click to expand...

Just to correct a common misunderstanding, the "float" voltage is whatever the alternator's internal regulator is set to - usually 14.0v or higher. The Sterling regulator can't decrease the alternator's voltage, it can only increase it.
 
AS there seems to several variables, the Sterling Unit, the alternator ( is the same as submitted for recon) I would vut the Sterling unit out for the time being, connecting the output from the alternator firectly to the battery.
I would expect the alternator provide 14+ volts with an engine at 2500 rpm.
If it does then the Sterling/alternator is the problem. If the laternator does not reach 14 volts, then it is the problem
 
survey advice needed

hi, i have taken the plunge and put a deposit on a 43 benetea cyclades.
i am having a survey done but will be doing an ispection myself to hopefully cut down time and costs. this will be before she is hauled out of the water..so would just like to ask some of you knowledgeable folk for tips on what to look out for.
thanks in advance.
ps..please no bleach box plastic tub type jokes am very sensative.!
 
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