Sterling Alternator to Battery Charger - unit will not stay off?

[windpipe]

Hello all,

I am wondering if anyone else has experienced a similar behavior of the Sterling ABC unit:

I can successfully power off the unit with the remote, but it turns itself back on after ~30 seconds to 2 min.

The US Sterling rep was helpful and sent me a new remote, but that did not fix the issue. I am yet to try replacing the cable. (I have a replacement and it is on my to-do list)

The US Sterling rep mentioned as a fail-proof option, a separate power switch can be wired in to the unit. He also said he'd be open to replacing the entire unit if we couldn't figure it out.

Has anyone else dealt with this?


My reason for wanting to turn the unit off, is that if I know I am going to get back to shore power in a few hours, I would rather not boost the alternator. It does shut off sometimes from the temp sensor, so I know the ABC is pushing it.

The ABC also seems to be mostly in bulk absorption mode - I have not seen it go to float. It seems to just be on a timer rather than reacting to the voltage of the battery bank.

This is a hard problem to troubleshoot, because the conditions where I am motoring for long periods are not that common.

[smac999]

All chargers use a timer to switch to float.

Because voltage durring the absorb is always the same from start to finish.

[windpipe]

Originally Posted by smac999

All chargers use a timer to switch to float.

Because voltage durring the absorb is always the same from start to finish.

OK, forgive me for not immediately accepting this.

The wording in the Sterling ABC manual is, "The unit’s intelligent software automatically calculates the optimum charge cycle and absorption time. When the batteries have been fully charged, the voltage is reduced to float voltage (appr. 13.5V to 13.8V) if For additional functions and improved performance some extra features can be possible, depending on the output voltage of the alternator.."

I understand this wording is vague and they are maybe dressing it up a little.

They also show the graph showing about 8 hrs of absorption time (see below). They specify this is for a 300 Ah 12 bank discharged to 40% SOC, charging with a 90 amp Bosch alternator.

I would think there would be some way for it to adapt to banks of vastly different sizes (Ah).

I was thinking that maybe the charger would briefly cycle off from time to time to check the bank voltage or something. But I am no expert so I could believe that that wouldn't work for various reasons.

[noelex 77]

Originally Posted by windpipe

OK, forgive me for not immediately accepting this.

The wording in the Sterling ABC manual is, "The unit’s intelligent software automatically calculates the optimum charge cycle and absorption time. When the batteries have been fully charged, the voltage is reduced to float voltage (appr. 13.5V to 13.8V) if For additional functions and improved performance some extra features can be possible, depending on the output voltage of the alternator.."

I understand this wording is vague and they are maybe dressing it up a little.

They also show the graph showing about 8 hrs of absorption time (see below). They specify this is for a 300 Ah 12 bank discharged to 40% SOC, charging with a 90 amp Bosch alternator.

I would think there would be some way for it to adapt to banks of vastly different sizes (Ah).

I was thinking that maybe the charger would briefly cycle off from time to time to check the bank voltage or something. But I am no expert so I could believe that that wouldn't work for various reasons.

The absorption time shown is certainly long. It looks to be just under 6 hours from the graph. This is a long absorption time, but the output in the example is reasonably high relative to the battery bank size , which will lengthen the required time in the absorption mode.

The Sterling alternator to battery chargers use a charging algorithm adopting a variable absorption time, based on the time taken in bulk, so they will automatically try to adjust the absorption time for different situations.

This is a common system adopted by many manufacturers for a multitude of charge sources.

It is not a perfect system and will on some occasions overcharge or undercharge the batteries. Unfortunately, it does not appear the Sterling alternator to battery chargers have any manual adjustment of the absorption time, which makes it much less likely that the absorption time will be appropriate in a wide range of installations.