Solar regulators and motoring

[Oceansailor]

Hi,

The problem:
After motoring for hours I arrive at the anchorage with app. 80% charge. The voltage has been high 14.3 as the alternators have been in bulk for 3 hours.

The solar regulators apparently think job is done as they have been seeing the bulk voltage for 3 hours and do not want to finish the job. The are in float mode.

The only way to get them going is to reset the two solar regulators (Mastervolt MPPT Chargemaster 25A) is to make them powerless for some seconds. After resetting they start charging.

Had a Chinese 40A MPPT that did exactly the same.

Have also a “dumb” cheap Chinese (MPPT ? Do not think so! ) This at least has a reset button on the unit.

Anyone recognizing the problem?

Are there any smarter units available?

[geoffr]

How are you determining your 80% charge?
Is it possible you are at 100%, but your meter is confused?

[Stu Jackson]

Make the target voltages on the regulator and controller different. Maine Sail has discussed this many times.

[Oceansailor]

Originally Posted by geoffr

How are you determining your 80% charge?
Is it possible you are at 100%, but your meter is confused?

When the I turn off the engine the batteries are still accepting 25A. When full they only accept 3-4A.

After reset the solar is putting in 15-20 A.

[Oceansailor]

Originally Posted by Stu Jackson

Make the target voltages on the regulator and controller different. Maine Sail has discussed this many times.

I kind of understand what you are suggesting. But still I dont?

Are you suggesting higher bulk voltage on the solar controller than on the regulator for the alternator?

[zboss]

My Victron controllers do the same thing.

I don’t seem to have a link to the Mainesail article or discussion containing the details of the proposed voltages... if someone can share it, we would appreciate it.

[roland stockham]

Originally Posted by Oceansailor

Hi,

The problem:
After motoring for hours I arrive at the anchorage with app. 80% charge. The voltage has been high 14.3 as the alternators have been in bulk for 3 hours.

The solar regulators apparently think job is done as they have been seeing the bulk voltage for 3 hours and do not want to finish the job. The are in float mode.

I appreciate that the post is about the solar controller but it may be you have another, or different problem. I would be concerned that, after 3 hours in bulk, your batteries only show 80%. This suggests either inadequate charging or very low batteries at the start. Unless the batt were under 50% to start would suggest a full system check including looking at the actual charge into the batteries. Would normlly expect to see around 20% charge increase per hr at least at the start, would seem you are a more like 10%.

[Locquatious]

Multi-stage charging cycles may be induced by turning off the solar controller and then turning it back on, or it may be a timed induced cycle...say time spaced during the day. Or the cycle may be induced when the batteries have sufficient discharge.

When you are motoring the alternator regulator takes over charging and the solar controller goes to float, which means it does not participate in charging. When the motor stops the batteries are charged, so the solar controller multi-stage charging is not induced.

It is not healthy for the batteries to be max voltage charged all the time. If you are re-setting the solar controller to multi-stage charge the batteries when they are full, you are just boiling them. It's like filling a coffee can with water, once it's full any extra water just spills over the sides.

[Oceansailor]

Originally Posted by roland stockham

I appreciate that the post is about the solar controller but it may be you have another, or different problem. I would be concerned that, after 3 hours in bulk, your batteries only show 80%. This suggests either inadequate charging or very low batteries at the start. Unless the batt were under 50% to start would suggest a full system check including looking at the actual charge into the batteries. Would normlly expect to see around 20% charge increase per hr at least at the start, would seem you are a more like 10%.

The house bank is 1100Ah. Start charging at 50%. It takes about 3 hours to get to around 80%. I’m quiet happy to reach 80% in 3 hours.

100% I would never try with the engine as it would take much to long.

[Oceansailor]

Originally Posted by Locquatious

Multi-stage charging cycles may be induced by turning off the solar controller and then turning it back on, or it may be a timed induced cycle...say time spaced during the day. Or the cycle may be induced when the batteries have sufficient discharge.

When you are motoring the alternator regulator takes over charging and the solar controller goes to float, which means it does not participate in charging. When the motor stops the batteries are charged, so the solar controller multi-stage charging is not induced.

It is not healthy for the batteries to be max voltage charged all the time. If you are re-setting the solar controller to multi-stage charge the batteries when they are full, you are just boiling them. It's like filling a coffee can with water, once it's full any extra water just spills over the sides.

Yes you are right, turning it off/on makes it forgett the float mode and it starts charging in bulk/absorbtion.

But the unit does not have a simple on/off button. Resetting the unit requires disconnecting the solar panels from the controller for a short while. Do not really fancy another switch on the cable between panel and controller as that is a source for additional voltage loss.

The hight voltage never really get much of an issue as that never is a problem when cruising and using power and the batteries and the controller always are in bulk or Absorbtion mode. I think I never seen voltage over 14V when on solar and cruising.

A simple reset button on the controller would have been making life easier.

[waterman46]

Originally Posted by geoffr

How are you determining your 80% charge?
Is it possible you are at 100%, but your meter is confused?

Definitely this must be determined. Do you use an AH meter on the battery bank?

After shutting down the engine and waiting a few minutes and turning on a moderate 12V load, is the battery voltage low enough to trigger a MPPT charge cycle? Not if bank is in good condition, and if so then you have no problem. But if the bank will accept a 25A charge after getting a long high current charge on alternator as you say, then the batteries may be sulfated.

[john61ct]

Originally Posted by roland stockham

Would normlly expect to see around 20% charge increase per hr at least at the start, would seem you are a more like 10%.

It's not all linear.

My AGMs can accept 140AH in the first hour, by the third only 30, the last 4% takes over three hours accepting under 10A.

[john61ct]

Originally Posted by Locquatious

If you are re-setting the solar controller to multi-stage charge the batteries when they are full, you are just boiling them.

Not with a modern quality controller.

By definition a full bank is only accepting tiny currents, and the SC will see that and go to float.

Of course you need to configure your SC correctly, but all their defaults result in premature infloatulation, not overcharging.

An hour of Absorb extra here and there does no harm tolead banks, even GEL.

[john61ct]

Originally Posted by waterman46

if the bank will accept a 25A charge after getting a long high current charge on alternator as you say, then the batteries may be sulfated.

Not at all necessarily.

Even with the highest currents getting the bank to 90% SoC, most still need several more hours at Absorb V to get to 100% Full, as per endAmps.

[john61ct]

OP, workaround alert.

Since the high current charging makes solar redundant, just wire a Blue Sea Dual Circuit switch, for both between the panels and SC, and to the bank.

No voltage loss worth worrying about.

After you shut down the engine, turn on the solar.