Mastervolt Charger/Oyster Question

[Kenomac]

Attempting to figure out my Mastervolt 24/50 charger controls along with my owners manual. There's a control knob I can't figure out what it does, nothing in the manual to explain it. On my breaker panel set up by Oyster Yachts back in 2002, there are light indicators and a "Charger" knob with settings "min-max" (See photo). I've tried turning the knob full each way while running the generator, but the voltage always reads 28.5v taken off the bus, turning the knob makes no difference.

The reason I'm asking, is I'm trying to figure out how to get my charger to go into equalization mode. The manual indicates that this can only be done using the Mastervolt "MasterBus Settings."

Does anyone know what this knob does?

[john61ct]

Guess, but adjust current amps?

[Kenomac]

John,

How would that be used?

[Bleemus]

The knob reduces amp draw from shore. Say you have a 30 amp supply and you need to draw 10 amps for AC to run a microwave. You would turn the charger down to not draw more than 20 amps to keep from popping the breaker on shore.

[john61ct]

When you don't want to pull too much power from the upstream source.

Or a smaller bank with a lower max charge rate spec.

[Kenomac]

All of these suggestions sound pretty good.

[exMaggieDrum]

IF the charger offers an equalization mode, it will, or should be, specifically described in the manual. It is a once in a while event and under control by the user, i.e. never automatic, so it should be documented. Some older/cheaper chargers don't have that as a feature. I would go to the Mastervolt support website and see if they offer a download of the manual for that specific model if you don't have one. As a last resort, contact them for help.

[Kenomac]

It appears as though I need a MasterBus unit in order to equalize. I checked the entire system this morning and it doesn't appear that I have one installed.

A project for later this season or early next.

[a64pilot]

Can you call the manufacturer? Or maybe Oyster?

[Kenomac]

I'll send a photo to Oyster on Monday, hopefully they'll know.

[neilsty]

Look at the manual for the actual charger, not the controller. On my similar vintage oyster it is located behind the aft starboard sofa back. There are dip switches on the side of the charger close to the top around the side from where the status lights are located. I believe that you use these to set the charging voltage higher for equalization. The manual should explain their location and settings. I have never tried this yet though, but did look into it when I had battery problems

[Kenomac]

Thanks, I'll look first thing tomorrow.

[poiu]

The charger leds and the charger dial on the main yacht panel should be connected to the charger using an RJ11 plug into socket 6 or 7 shown on page 12 of the manual. The charger dial serves to control the charge current. To get at the socket you have to remove the bottom panel of the charger. You will need one per charger and as you have, it seems only one set of lights and dial then I think the second charger has to be on auto/full power only.

Just next to the socket are the dip switches. If you establish the correct battery charging voltage from the battery manual you can adjust the dip switches using the table on page 16 to the correct voltage. To keep the batteries in best health they need to be at float voltage for the longest time. They will be pretty much equalised after a few days at float voltage.

If you feel you need to equalise at high voltage then you have to buy the Mastervolt PC software and cable or their proprietary display as you can't set the charger any other way, though I did read someone did it somehow with a terminal program used on another Mastervolt product.

[john61ct]

Originally Posted by poiu

To keep the batteries in best health they need to be at float voltage for the longest time. They will be pretty much equalised after a few days at float voltage.

If you feel you need to equalise at high voltage then ...

The term "conditioning" may be better, most FLA do need a monthly high voltage cycle as per mfg protocol.

Sitting at float does nothing for the bank but prevent self-discharge.

For good health the bank should stay at absorb voltage until 100% full. This is hard, most profiles go to float too early.

[poiu]

Originally Posted by john61ct

Sitting at float does nothing for the bank but prevent self discharge.

That's not correct. It does something very useful, which is to prevent most sulphate build up on the plates, which mainly occurs if the battery is left partially charged.