Charging issue - alternator / split charge question

[Adamf5023]

Thanks everyone for your suggestions. I am going to trace the main charge lead from the alternator to verify where it goes to and then from there if there is any additional wiring to a diode pack or split charge relay / fuse etc. The system used to work OK and I know that the charge is not floating as the house batteries were discharged. I am sure it must be something simple. I will drop a note back with what I find. Again - I appreciate your comments and help.

After further investigation I found the split charge relay and wiring but it was disconnected and taped up out of the way. There must be an alternative solution that was installed when the new engine was fitted. I traced the wires back from the alternator and the charging wire terminates at the +ve battery lead and terminal of starter motor. The battery lead from the starter is connected to the +ve isolator switch for the engine.
There is an additional thick red +ve lead that comes from the starter to the black box which provides connectivity to the starter panel in the cockpit (for start / stop / glow plugs etc).
There is a thick red lead that comes off the domestic battery isolator switch and eventually goes to terminals behind the switch panel near the nav table. I cannot see any diode pack or similar behind the panel so I am now at a loss as to where the alternative split charge solution is fitted.

 

[halcyon]

After further investigation I found the split charge relay and wiring but it was disconnected and taped up out of the way. There must be an alternative solution that was installed when the new engine was fitted. I traced the wires back from the alternator and the charging wire terminates at the +ve battery lead and terminal of starter motor. The battery lead from the starter is connected to the +ve isolator switch for the engine.

Volvo have fitted alternators with splitter diodes built into back face, that had two positives outputs one to engine battery, the other to service battery.

Brian

 

[PaulRainbow]

After further investigation I found the split charge relay and wiring but it was disconnected and taped up out of the way. There must be an alternative solution that was installed when the new engine was fitted. I traced the wires back from the alternator and the charging wire terminates at the +ve battery lead and terminal of starter motor. The battery lead from the starter is connected to the +ve isolator switch for the engine.
There is an additional thick red +ve lead that comes from the starter to the black box which provides connectivity to the starter panel in the cockpit (for start / stop / glow plugs etc).
There is a thick red lead that comes off the domestic battery isolator switch and eventually goes to terminals behind the switch panel near the nav table. I cannot see any diode pack or similar behind the panel so I am now at a loss as to where the alternative split charge solution is fitted.

With the alternator output going to the starter +VE you will not have a diode pack, or similar.

If you have a VSR, which would be typical with this type of setup, it will need a positive cable from both batteries. These connections could be made at the batteries or at the isolator switches. Your engine wiring will likely be the easiest to trace, as you have already looked at that. Are there any other wires connected to the battery positive or to the battery terminal on the isolator ?

 

[Adamf5023]

With the alternator output going to the starter +VE you will not have a diode pack, or similar.

If you have a VSR, which would be typical with this type of setup, it will need a positive cable from both batteries. These connections could be made at the batteries or at the isolator switches. Your engine wiring will likely be the easiest to trace, as you have already looked at that. Are there any other wires connected to the battery positive or to the battery terminal on the isolator ?

Hi - there is a wire connected to the +ve terminal of the domestic battery with a 10A fuse that feeds an auxiliary circuit behind the switch panel in the saloon. There is also one connected to the engine battery which looks to feed the Mikuni heater unit.
There are a lot of wires connected at the isolator switches but none this enough to carry current from the alternator. I have had the boat for about 5 years and have had no charging issues until recently. I have a Cristec CPS 600 battery charger on board. This battery charger is designed to charge both the domestic and engine batteries and has done so without issue in the past. . I am going to check on Friday when I plug into shore power to see if this is related and is now an issue charging the domestic batteries.

 

[PaulRainbow]

Hi - there is a wire connected to the +ve terminal of the domestic battery with a 10A fuse that feeds an auxiliary circuit behind the switch panel in the saloon. There is also one connected to the engine battery which looks to feed the Mikuni heater unit.
There are a lot of wires connected at the isolator switches but none this enough to carry current from the alternator. I have had the boat for about 5 years and have had no charging issues until recently. I have a Cristec CPS 600 battery charger on board. This battery charger is designed to charge both the domestic and engine batteries and has done so without issue in the past. . I am going to check on Friday when I plug into shore power to see if this is related and is now an issue charging the domestic batteries.

It sounds like there is a possibility that your alternator has never charged the domestic bank and you haven't noticed. Perhaps the shore power charger has stopped charging the domestics or perhaps the batteries are getting tired and have brought the issue to light ?

Would be very easy to connect a VSR, perhaps the one that's there would still work if you wired it up ?

 

[biscuit]

Slight thread drift......... What's the difference between a DVSR and an ACR, please?

 

[Adamf5023]

It sounds like there is a possibility that your alternator has never charged the domestic bank and you haven't noticed. Perhaps the shore power charger has stopped charging the domestics or perhaps the batteries are getting tired and have brought the issue to light ?

Would be very easy to connect a VSR, perhaps the one that's there would still work if you wired it up ?

Thanks again for the reply. I am slowly coming to that assumption however I can't understand how in all the months that the boat has been in the water that the batteries are just starting to show discharge. The 3 100A batteries were new about 12 months ago. The boat is kept on a swing mooring and so no shore power connected. I also don't understand why the original split charge system was disconnected and taped up and out of the way. I will take another look at the wiring at the weekend and I will also check the Cristec charging system when I do connect the shore power. If I cannot see anything to support another solution being installed then I will look to install either the original split charge relay system or an alternative. The original system has the leads which connected to the isolator switches. The relay is 70A but the alternator output is rated at 150A. Not an issue unless the batteries are very discharged and I do not use an inverter for anything.

 

[VicS]

Thanks again for the reply. I am slowly coming to that assumption however I can't understand how in all the months that the boat has been in the water that the batteries are just starting to show discharge. The 3 100A batteries were new about 12 months ago. The boat is kept on a swing mooring and so no shore power connected. I also don't understand why the original split charge system was disconnected and taped up and out of the way. I will take another look at the wiring at the weekend and I will also check the Cristec charging system when I do connect the shore power. If I cannot see anything to support another solution being installed then I will look to install either the original split charge relay system or an alternative. The original system has the leads which connected to the isolator switches. The relay is 70A but the alternator output is rated at 150A. Not an issue unless the batteries are very discharged and I do not use an inverter for anything.

The relay, or split charge device, ought to be rated to take the full alternator output, esp with 300Ah of battery capacity . Maybe that's why it's not connected.

 

[pvb]

The relay, or split charge device, ought to be rated to take the full alternator output, esp with 300Ah of battery capacity . Maybe that's why it's not connected.

Maybe it failed and was disconnected...

 

[pvb]

Slight thread drift......... What's the difference between a DVSR and an ACR, please?

An ACR (automatic charging relay) is essentially the same as a VSR (voltage sensitive relay). Blue Sea tend to like to call their VSRs by the term ACR.

 

[VicS]

An ACR (automatic charging relay) is essentially the same as a VSR (voltage sensitive relay). Blue Sea tend to like to call their VSRs by the term ACR.

and DVSR ?

Digital VSR ???

 

[PaulRainbow]

and DVSR ?

Digital VSR ???

Yes, according to BEP

 

[pvb]

Yes, according to BEP

Basically a bit of marketing hype, as all VSRs are to some degree digital, although the BEP one has the facility to turn itself off if the ignition switch is off, giving a claimed zero current consumption. This is a questionable benefit, as most VSRs consume hardly anything when the relay isn't closed (Victron Cyrix quotes 4mA, for example).

 

[PaulRainbow]

Basically a bit of marketing hype, as all VSRs are to some degree digital, although the BEP one has the facility to turn itself off if the ignition switch is off, giving a claimed zero current consumption. This is a questionable benefit, as most VSRs consume hardly anything when the relay isn't closed (Victron Cyrix quotes 4mA, for example).

I agree. Much of the marketing for VSRs is hype. They serve a useful purpose in a lot of cases, but often don't live up to the sales blurb.

 

[halcyon]

I agree. Much of the marketing for VSRs is hype. They serve a useful purpose in a lot of cases, but often don't live up to the sales blurb.

Marketing rarely understand the product or it's operation, why should a VSR be different.

What to you want do, that a VSR's fails to do out of interest.

Brian

 

[PaulRainbow]

Marketing rarely understand the product or it's operation, why should a VSR be different.

What to you want do, that a VSR's fails to do out of interest.

Brian

I'm happy happy with what a decent VSR does and how it does it Brian. But the marketing for some VSRs make claims that just aren't true, in particular they talk about a VSR fully charging a particular battery before closing to charge the other batteries, they simply don't do that. It's a silly claim, because they don't need to do that anyway.