MD2030D charging voltage

[ithet]

I have a MD2030D on a 2004 yacht. I never see over 13.8b off the alternator. I am currently charging the depleted 270ah house bank and the alternator is outputting 31a at 13.7v. Voltage levels checked on two devices. Is this normal for this alternator? I would have expected 14.4v. I have a VCR in the system, no diodes.

 

[ylop]

I have a VCR in the system, no diodes.

Presumably you mean VSR - unless you are trying to record what’s happening!

 

[john_morris_uk]

There’s two sides to the OP’s question. Firstly there’s the problem of ‘acceptance’ of a lead acid battery as with a standard traditional alternator regulator you can’t force the batteries to accept more charge. It’s pumping in 31 amps so it’s definitely working. That might be all they’ll take with this setup. Secondly, 13.7 is very close to the normally accepted charging voltage for lead acid batteries. 13.8-14.5 were the figures I recall? Maybe the regulator is slightly low, but it’s not a disaster.

When we had a Volvo 2040 we had a smart regulator fitted to the alternator externally. It was one of those clever three stage ones. Worked a treat. Sterling Power Pro Reg DW Advanced Alternator Regulator 12/24V - PDARW

You might also explore Alternator to Battery Charger or a Battery to Battery charger options?

 

[Alex_Blackwood]

I have a MD2030D on a 2004 yacht. I never see over 13.8b off the alternator. I am currently charging the depleted 270ah house bank and the alternator is outputting 31a at 13.7v. Voltage levels checked on two devices. Is this normal for this alternator? I would have expected 14.4v. I have a VCR in the system, no diodes.

Is your alt. self regulated, i.e. internal regulator, or do you have some other external form of regulation. Where is the alternator sensing its voltage from. Is it machine sensed (from its own output) or is it sensing from an external regulator or one of your battery banks. If it is sensing the the engine start battery that is a possible cause? What is the make and type of alternator. What are its specifications?
+ 1 for JM's post.

 

[ithet]

Internally regulated, all as standard except for VSR. I am really asking if this is normal for an MD2030D or do I have an issue. The batteries are charging but I assume not as fully as they should.

 

[VicS]

I have a MD2030D on a 2004 yacht. I never see over 13.8b off the alternator. I am currently charging the depleted 270ah house bank and the alternator is outputting 31a at 13.7v. Voltage levels checked on two devices. Is this normal for this alternator? I would have expected 14.4v. I have a VCR in the system, no diodes.

If it is the standard alternator you should see 14.0 to 14.4volts at the alternator terminals Workshop manual page 68 The difference between the alternator output and the battery terminals should not be more that 0.4 volt.

If you are seeing only 13.8 volts at the alternator terminals the regulator may be faulty.

Getting the alternator checked by an auto- electrician would be a wise move

 

[ithet]

If it is the standard alternator you should see 14.0 to 14.4volts at the alternator terminals Workshop manual page 68 The difference between the alternator output and the battery terminals should not be more that 0.4 volt.

If you are seeing only 13.8 volts at the alternator terminals the regulator may be faulty.

Getting the alternator checked by an auto- electrician would be a wise move

Thanks Vic, that was information I was looking for.

 

[wonkywinch]

As mentioned on other threads, check your multimeter is accurate. My cheap Screwfix one reads 15v when the Fluke shows 14.3v.

 

[Metalicmike]

I knew someone years ago who bought a tape measure, it was ok until he had to cut to a fixed length, that's when he found that the first inch on the tape was missing making it 1 inch short.

 

[wonkywinch]

I knew someone years ago who bought a tape measure, it was ok until he had to cut to a fixed length, that's when he found that the first inch on the tape was missing making it 1 inch short.

Talking of which, the reason the end of a tape measure is loose ..

 

[B27]

I have a MD2030D on a 2004 yacht. I never see over 13.8b off the alternator. I am currently charging the depleted 270ah house bank and the alternator is outputting 31a at 13.7v. Voltage levels checked on two devices. Is this normal for this alternator? I would have expected 14.4v. I have a VCR in the system, no diodes.

That sounds like the low end of normal.
It might produce a bit over 14V with no load, but you're pulling 31A from what might be a 45A alternator.

The batteries must be pretty low to put >C/10 in at only 13.7V?
I'd be checking they are all Ok and none is getting hot.

What voltage do you get on the engine battery, if you disable the VSR?

It's possible your alternator is quite hot, it's working hard, this may cause it to reduce the output.

As your post was 2 1/2 hours ago, I expect the current has dropped a bit and the volts come up a bit by now?

 

[PaulRainbow]

I have a MD2030D on a 2004 yacht. I never see over 13.8b off the alternator. I am currently charging the depleted 270ah house bank and the alternator is outputting 31a at 13.7v. Voltage levels checked on two devices. Is this normal for this alternator? I would have expected 14.4v. I have a VCR in the system, no diodes.

Where are you taking the voltage measurements and what exactly are you using ?

 

[ithet]

You do know there are no horses on the Isle of Wight. People prefer Cowes to Ryde.

That sounds like the low end of normal.
It might produce a bit over 14V with no load, but you're pulling 31A from what might be a 45A alternator.

The batteries must be pretty low to put >C/10 in at only 13.7V?
I'd be checking they are all Ok and none is getting hot.

What voltage do you get on the engine battery, if you disable the VSR?

It's possible your alternator is quite hot, it's working hard, this may cause it to reduce the output.

As your post was 2 1/2 hours ago, I expect the current has dropped a bit and the volts come up a bit by now?

Have been on batteries plus some solar for a few days so batteries were down to 12.4v with fridge load only before I started charging. Batteries are fairly new. Now alternator giving 14a and 14.0v, so maybe not so bad?

 

[B27]

Have been on batteries plus some solar for a few days so batteries were down to 12.4v with fridge load only before I started charging. Batteries are fairly new. Now alternator giving 14a and 14.0v, so maybe not so bad?

Sounds quite normal, in a 1990's kind of way....

 

[Boater Sam]

So nowt wrong with it. Just low batteries taking max from alternator which gets hot and reduces output a bit. 12.4 is nearing flat for LA battery.

 

[ithet]

Sounds quite normal, in a 1990's kind of way....

So nowt wrong with it. Just low batteries taking max from alternator which gets hot and reduces output a bit. 12.4 is nearing flat for LA battery.

Yeah very 90s. Not usually off marina power for this long.

 

[ithet]

Where are you taking the voltage measurements and what exactly are you using ?

I have a BEP monitor and it's figures agree with Victron smart solar House battery voltage. I have also confirmed the BEP reading with a voltmeter across battery terminals in the past.

 

[PaulRainbow]

So nowt wrong with it. Just low batteries taking max from alternator which gets hot and reduces output a bit. 12.4 is nearing flat for LA battery.

Away with you, 12.4v is over 70% charged !!

 

[PaulRainbow]

Sounds quite normal, in a 1990's kind of way....

What on Earth does that mean ?

 

[PaulRainbow]

I have a BEP monitor and it's figures agree with Victron smart solar House battery voltage. I have also confirmed the BEP reading with a voltmeter across battery terminals in the past.

You should take a reading from the alternator terminal for a more accurate reading. The take one at the batteries too.