Charging problems after changes made to accommodate a Balmar regulator.

[GILow]

Tell me if I’m wrong, but I assumed the Balmar used PWM on the field?

[goboatingnow]

It’s most likely the balmar isn’t supplying ( for whatever reason ) enough field current

[Wotname]

Originally Posted by GILow

Tell me if I’m wrong, but I assumed the Balmar used PWM on the field?

Not sure what your point is regarding how the regulator controls the field current - please excuse if I am missing something bludi obvious!

[wholybee]

I found that my balmar regulator reduced output significantly when battery temp compensation was used, even if the batteries were well below the set compensation temperature, and the Balmar display confirmed the temp sensor was working properly. I ended up installing a switch in line with the temp probe, and got nearly twice the output when it was turned off. So I would start there.

[GILow]

Originally Posted by Wotname

Not sure what your point is regarding how the regulator controls the field current - please excuse if I am missing something bludi obvious!

If it’s PWM then measuring voltage supplied to the field is tricky. I’m not sure how you’d do that. Smac99 is suggesting they measure the field voltage.

[GILow]

Originally Posted by wholybee

I found that my balmar regulator reduced output significantly when battery temp compensation was used, even if the batteries were well below the set compensation temperature, and the Balmar display confirmed the temp sensor was working properly. I ended up installing a switch in line with the temp probe, and got nearly twice the output when it was turned off. So I would start there.

I think this is not the issue as the current increases with engine rpm.

[Wotname]

Originally Posted by GILow

If it’s PWM then measuring voltage supplied to the field is tricky. I’m not sure how you’d do that. Smac99 is suggesting they measure the field voltage.

WAG - I expect the 'freq' of any PWM will be higher than the sampling rate of any average DVM and thus one would get a meaningful average value of the field voltage - but I could be wrong and if I am, I'm sure someone will jump in and correct any erroneous information.

[CharlieJ]

Temperature sensors do go bad...even out of the box. A simple test would be to deplete the batteries, run the engine as before and disconnect the battery temperature sense and then the alternator temperature sense while monitoring alternator output.

[wholybee]

Originally Posted by GILow

I think this is not the issue as the current increases with engine rpm.

Yes, that was the case as well. Certainly worth a check, just unplug the temp sensor.

[smac999]

Originally Posted by GILow

Tell me if I’m wrong, but I assumed the Balmar used PWM on the field?

it’s just voltage controlled. ~13v is max feild. 7v half field ect.

If you set the belt manager it just limits max feild voltage. Ie you’ll never see over 10v on the feild Wire.

If it is pwm , it’s fast enough you can measure different voltages with a volt meter. Or it’s analog voltage. Not sure

[GILow]

Originally Posted by smac999

it’s just voltage controlled. ~13v is max feild. 7v half field ect.

If you set the belt manager it just limits max feild voltage. Ie you’ll never see over 10v on the feild Wire.

If it is pwm , it’s fast enough you can measure different voltages with a volt meter. Or it’s analog voltage. Not sure

Well, no harm in them checking it. I’ll see what reading they get.

[GILow]

Originally Posted by wholybee

Yes, that was the case as well. Certainly worth a check, just unplug the temp sensor.

I’ll get them to check this too.

[GILow]

So, here’s the latest. Interesting outcome:


————————————————————————————


Thank you to all on Cruisers Forum for their input and suggestions.

We just wanted to give an update of the results of some further tests.

With the advanced program set as previously described, and with battery volts at 13.2v, and revs at 1500, we got 30 amps out of the alternator.

We went back to neutral, reset the alternator to its factory default settings for Flooded Deep Cycle batteries, put the revs back up to 1500 and got 45 amps.

We went back to neutral, went into the advanced settings and set them back to what we had previously (the float and absorption at 14.8v, absorption minimum time at 2 hours) and then the ONLY thing we did differently was change the bulk minimum time to 2 hours. We put the revs back up to 1500 and got 40+ amps again.

This would suggest that the minimum bulk time being left at the default of 18 mins was the setting that was reducing the output of the alternator when it was aiming for 14.8v, however, this was not the case when the default settings for Flooded Deep Cycle batteries were used (which also have a default minimum bulk time of 18 minutes but a bulk voltage of 14.6v) when we were getting 45 amps from the alternator.

In reading around it appears that the field threshold setting, the default setting for which is 65% for bulk to absorption, may be worth playing with to ensure we are getting maximum current when we are in bulk mode (or absorption 1 as it really is).

Regardless, increasing the minimum bulk time as suggested has resulted in our alternator once again producing an output of around 45 amps at low SOC.

Thanks again to all. And of course if we figure out anything else we will update.

Cheers

[sailinglegend]

I think you may need to read around a bit more - or talk to Balmar about why increasing the minimum bulk time from 18 mins to 120 mins cured your problem.

18 mins does seem very short but as I understand it that duration is considerably extended by the field threshold setting - when it is needed. So if the batteries are flat then it automatically stays in bulk for longer. But if the batteries are fully charged - after being on shore power all night - then whilst motoring out of the marina the alternator bulk voltage will be reached very quickly and then stay there in absorption for a further 120 mins. That's 4 hours at absorption voltage when the batteries are already fully charged. This is "over-charging" - maintaining too high a voltage for the state of charge of the batteries. This causes excessive gassing which is fatal for sealed batteries. You can't overcharge batteries with too high a current - they take what they want.

[GILow]

Originally Posted by sailinglegend

I think you may need to read around a bit more - or talk to Balmar about why increasing the minimum bulk time from 18 mins to 120 mins cured your problem.



18 mins does seem very short but as I understand it that duration is considerably extended by the field threshold setting - when it is needed. So if the batteries are flat then it automatically stays in bulk for longer. But if the batteries are fully charged - after being on shore power all night - then whilst motoring out of the marina the alternator bulk voltage will be reached very quickly and then stay there in absorption for a further 120 mins. That's 4 hours at absorption voltage when the batteries are already fully charged. This is "over-charging" - maintaining too high a voltage for the state of charge of the batteries. This causes excessive gassing which is fatal for sealed batteries. You can't overcharge batteries with too high a current - they take what they want.

Yes, it does need further investigation.

Thankfully the boat in question is not a dock-queen, but it does have some solar capacity so there’s a chance of a late afternoon motoring session causing the problems you’ve flagged.

The owners are watching this thread, but I’ll make sure they’ve read your cautionary note.

I think they were considering getting in touch with Maine Sail for assistance if they couldn’t sort it out to their satisfaction. I’m not much help, I’m a solar guy. My engine charging setup is brutally primitive.