Batteries Overcharging

[Markb250]

I have a Yanmar 4JH4-TE driving a Hitachi LR 180-30C 22V 80A alternator, charging 4 x 100Ah lead acid house batteries. An Adverc battery management system is installed.

I have shore power coming through a Mastervolt charger/invertor and 270W of solar power via a Victron MPPT controller. The solar setup includes a Victron battery monitor installed with the supplied shunt.

With the engine running, the battery charge is going to 15V and beyond. Disconnecting the Adverc BMS has no effect. This is not happening with shore power or solar. The batteries are only 18 months old and all test OK with a multimeter voltage test.

I've sent the alternator off to Yanmar (Athens) assuming a faulty voltage regulator, but following extensive testing, it checked out OK so the regulator was not replaced.

The problem seems to have developed intermittently prior to installation of the solar system, however I wouldn't rule the solar installation out of the equation just yet.

With movement restrictions easing here in Greece next week I'll be able to get a second opinion on the alternator regulator.

If not the voltage regulator in the alternator, does anyone have any thoughts on what the cause of the overcharging is?

[a64pilot]

I have several charging systems on my boat, two shorepower chargers, a kilowatt of Solar and of course an alternator. They all ignore each other, In fact I have set my Solar to run .1V higher than the shorepower chargers, and when Solar can carry the load, the shorepower chargers drop to zero output as they are set .1V lower.
Assuming your charge sources are independent, they should not affect each other.

But if your running the alternator output through some kind of system before it’s connected to the batteries, then that may could be the problem.

[GordMay]

Greetings and welcome aboard the CF, Mark.

[DefinitelyMe]

15V is not too high if your charging system is temperature compensated and if it is cold where you are.

15V corresponds to the correct charging voltage during absorption stage if it is approximately zero degrees Celsius. If it's colder than that it will go even higher.

Could that be it?

[Markb250]

Thanks for the welcome GordMay. Much appreciated. It's nice to be able to reach out like this and I hope I can help someone else when the opportunity arises.

Thanks A64 Pilot. The alternator is direct to the batteries apart from the BMS.

Thanks Definitely Me. You've got me thinking. Ambient temp here is 20 C though. If there is sufficient load, or depth of discharge, not a problem. It's just not reacting to the push back from fully charged batteries.

[DefinitelyMe]

Originally Posted by Markb250

Thanks for the welcome GordMay. Much appreciated. It's nice to be able to reach out like this and I hope I can help someone else when the opportunity arises.

Thanks A64 Pilot. The alternator is direct to the batteries apart from the BMS.

Thanks Definitely Me. You've got me thinking. Ambient temp here is 20 C though. If there is sufficient load, or depth of discharge, not a problem. It's just not reacting to the push back from fully charged batteries.

Hmmm, not a temp. Compensation then. Not if it's 20C. Only happens with the engine running...... But alternator checks out ok at the shop. Forgive me if this is a stupid question but it couldn't be a 24V alternator regulator could it?.........

[smac999]

If the boat is unplugged. And the solar is covered. (Easy to rule out solar). And the only charge is from the engine. Then the alt is causing the 15v. But we need more info.

First I have no idea what a arc battery management sysysten is. And why you have a bms on flooded batteries...

It sounds like the alt is internal regulated?

Where does the pos wire run too? Hiuse bank? Engine bank? Isolator?

Does the alt have a voltage sense wire? If so where does it connect to?

With all the other stuff you have there. It’s time for an external regulator. You have 1 peice of junk among many other good parts.

[Markb250]

The regulator has been OK for 10 years and supposedly tests OK on the bench, so I have to assume it's 12V.

Adverc is an external regulator, POS to batteries. There is no sense wire and the alt. does have a fairly unintelligent internal regulator.

[DefinitelyMe]

Originally Posted by Markb250

The regulator has been OK for 10 years and supposedly tests OK on the bench, so I have to assume it's 12V.

Adverc is an external regulator, POS to batteries. There is no sense wire and the alt. does have a fairly unintelligent internal regulator.

I'm not familiar with Adverc, but the external regulators often work by fooling the internal regulator into thinking the battery voltage is lower than it actually is. Maybe bypass the adverc (allow the internal regulator to take over). If it solves the problem then the problem is the Adverc. What do you think?

[Markb250]

Thanks DM. Problem persists with the Averc disconnected. It's a UK product by the way, recommended to me by another sailor and does an excellent job of bringing the batteries up to full charge.
The main plan at the moment is to get a second opinion on the regulator, hopefully someone on the boat, with better diagnostic expertise than mine ( any passer by would qualify!)

[a64pilot]

What is the alternators specification? Assumption is it’s operating within its limits, but you need to know what those are.
If it is and you desire a different voltage , then you need to replace the regulator, replace the alternator with one made for an external reg, or have it modified for external regulation.

I don’t know what your BMS is, but assume it’s an attempt to get to three stage charging with single stage sources? I.E. drop to float voltage at some predetermined point?

This it, but no explanation of how It works, what it does etc.
https://adverc.co.uk/collections/adv...attery-systems

[Richv]

Originally Posted by Markb250

I have a Yanmar 4JH4-TE driving a Hitachi LR 180-30C 22V 80A alternator, charging 4 x 100Ah lead acid house batteries. An Adverc battery management system is installed.

I have shore power coming through a Mastervolt charger/invertor and 270W of solar power via a Victron MPPT controller. The solar setup includes a Victron battery monitor installed with the supplied shunt.

With the engine running, the battery charge is going to 15V and beyond. Disconnecting the Adverc BMS has no effect. This is not happening with shore power or solar. The batteries are only 18 months old and all test OK with a multimeter voltage test.

I've sent the alternator off to Yanmar (Athens) assuming a faulty voltage regulator, but following extensive testing, it checked out OK so the regulator was not replaced.

The problem seems to have developed intermittently prior to installation of the solar system, however I wouldn't rule the solar installation out of the equation just yet.

With movement restrictions easing here in Greece next week I'll be able to get a second opinion on the alternator regulator.

If not the voltage regulator in the alternator, does anyone have any thoughts on what the cause of the overcharging is?

Many high-output alternators have a separate voltage-sense lead. I have seen this happen when the voltage sense lead is open or has a bad connection.