Charging Problem for the hard of understanding.

[oldgit]

The situation so far. .
Engine start batteries charge from Genny and Shore power.
Both sets of batteries Leisure and Starter charge via Genny and Shore Power.
Problem is charging when underway via engine alternators.
Leisure batteries ( both tested OK) will not charge unless EMG/ All is switched ON while underway .
Volts as tested at batteries with multimeter and no load.

Suspect the starboard alternator has a problem ?

 

[Alex_Blackwood]

The situation so far. .
Engine start batteries charge from Genny and Shore power.
Both sets of batteries Leisure and Starter charge via Genny and Shore Power.
Problem is charging when underway via engine alternators.
Leisure batteries ( both tested OK) will not charge unless EMG/ All is switched ON while underway .
Volts as tested at batteries with multimeter and no load.
View attachment 185614
Suspect the starboard alternator has a problem ?

Paul R is probably your man for this. However, I would suggest that you have an installation wiring problem with your switching arrangements, at the very least.
I would suggest that a more detailed description of your installation, perhaps a wiring diagram, if you can, is needed before any meaningful reply can be given.
Sorry to be a bit negative in reply.

 

[salar]

Hard of understanding here too, but I also have a multi charge, multi battery option. The problem with charging multiple batteries is that the alternator will sense the battery capacity and stop charging at a lower level than max, and if there is more than one battery connected that complicates the ability to sense. Some have a separate sensing wire. Shore power charging doesn't have that restriction so it charges batteries that the alternator thinks are charged enough. There are lots of options for this to go wrong through faulty connections or incorrect wiring. My solution was to fit a Victron battery management system, wire it in properly and leave it to look after things. It's working wel!

 

[Refueler]

Just 'spit-balling' here ....

Is your alternator charging to Start bank and then a VSR to charge leisure bank ? Maybe if start bank is not ON then the VSR will not redirect charge as it needs start batts to be fully charged and 'ON' ? Assuming that you are using Leisure batts to start engines - that could mean alternator is not being excited to start charging - VSR is in the way ?

 

[Sandy]

What voltage is your alt producing?

If it is charging your starter batteries OK, but

Leisure batteries ( both tested OK) will not charge unless EMG/ All is switched ON while underway .

sounds like somebody has not wired up the output from the alt to the switch/batteries correctly.

 

[PaulRainbow]

Stb alternator does look suspect with the Emg switch on, but something is odd with the Emg switch off, looks like no charging unless both engines are running, odd.

It looks almost certain that whatever split charging device you have is not working.

What switching do you have ?

How are the batteries connected, both engines start from engine batteries, or one from engine battery and the other from the domestics, or what ?

Can you post a pic of the alternators (wiring end) ?

Any sign of a VSR or diode pack etc ?

Remind me what boat, engines ?

 

[Alex_Blackwood]

Stb alternator does look suspect with the Emg switch on, but something is odd with the Emg switch off, looks like no charging unless both engines are running, odd.

It looks almost certain that whatever split charging device you have is not working.

What switching do you have ?

How are the batteries connected, both engines start from engine batteries, or one from engine battery and the other from the domestics, or what ?

Can you post a pic of the alternators (wiring end) ?

Any sign of a VSR or diode pack etc ?

Remind me what boat, engines ?

+1 for that, decidedly odd

 

[oldgit]

Thanks for all suggestions.
Down to boat today to check some of the above.
The set up is in a ACM Excellence 38 with pair of 240HP Yanmars and a couple of 60 A Hitachi ????? alternators.
Will check both alternators are working today, attempt to locate the split charging device andto identify what type and make.

 

[Nauti Fox]

Thanks for all suggestions.
Down to boat today to check some of the above.
The set up is in a ACM Excellence 38 with pair of 240HP Yanmars and a couple of 60 A Hitachi ????? alternators.
Will check both alternators are working today, attempt to locate the split charging device andto identify what type and make.

Shall I ask the emergency services to standby in case you get entangled and stuck upside down somewhere in the boat?

 

[Refueler]

Shall I ask the emergency services to standby in case you get entangled and stuck upside down somewhere in the boat?

I know you jest ... but having got trapped in a space on a boat - its terrifying !

Luckily training kicked in about relax and slow down the breathing ... managed to extricate myself.... but it took ages !!

 

[oldgit]

The alternators are 80A not 50A and both putting about 14.50 V.
Found the Diode thingy (stop me if am getting to technical ) and got the following readings.

Why does the splitter appear to be working with one engine but not the other.
Confused of Medway.

 

[PaulRainbow]

The alternators are 80A not 50A and both putting about 14.50 V.
Found the Diode thingy (stop me if am getting to technical ) and got the following readings.

Why does the splitter appear to be working with one engine but not the other.
Confused of Medway.

Because the upper brown wire goes to the Stb alternator, there is no connection to the port alternator. For the port alternator to charge both batteries you would need a second diode.

 

[Sandy]

Interesting to see three bolts on the centre in line and the fourth one off to the side of the diode thingy.

I'd be playing with the multimeter working out what the paths were.

 

[PaulRainbow]

Interesting to see three bolts on the centre in line and the fourth one off to the side of the diode thingy.

I'd be playing with the multimeter working out what the paths were.

Top one is IN from the alternator, bottom three are OUT to batteries.

 

[wingcommander]

I know you jest ... but having got trapped in a space on a boat - its terrifying !

Luckily training kicked in about relax and slow down the breathing ... managed to extricate myself.... but it took ages !!

Agree , almost got stuck in a locker . A reminder now is to make sure I can reach my mobile.

 

[PaulRainbow]

The alternators are 80A not 50A and both putting about 14.50 V.
Found the Diode thingy (stop me if am getting to technical ) and got the following readings.

Why does the splitter appear to be working with one engine but not the other.
Confused of Medway.

The battery voltages with the port engine running look high, is the mains charger on ? If so, you need it off for a while before taking readings.

Some of the readings in your first table don't make sense, did you also have mains charging when you took those ?

When you get to the bottom of this i would get rid of the diode, it's using a significant amount of volts.

For now, forget about running both engines and forget about the Emg switch, mains and generator charging. Concentrate on the engines.

Run the Stb engine (mains charger off) and take voltage readings at the alternator, the terminals on the diode and the batteries. Do this all at once, no other charging and no loads.

1) Turn everything off, remove the middle brown wire and put it on the top terminal, with the other brown wire. Run the engine and take voltage readings at both batteries.

2) Return the brown wire from whence it came. Remove the red wire and fit it to the top terminal, with the brown wire and take readings from both batteries again.

Under no circumstances remove any of the diode wires with the engine running, or run the engine with the top wire disconnected.

EDIT : If you find a satisfactory voltage at the domestic batteries while doing tests 1 and 2 you can leave the domestic wire on the top terminal as a temporary work around. For a permanent fix, remove the diode, fit a power post and connect the alternator wire, the domestic battery wire and a wire to a VSR to it. The connect the engine battery wire to the other terminal of the VSR. This allows both alternators, mains power and the generator to charge both batteries.

Ref the generator, i suspect it's not charging the batteries, but powering the mains charger, but i could be wrong.

 

[Sandy]

Top one is IN from the alternator, bottom three are OUT to batteries.

We can only deduct that only one alternator is connected.

Is there a second input from an alternator or is the diode thingy capable of running with both alternator connected to the top bolt?

 

[PaulRainbow]

We can only deduct that only one alternator is connected.


Is there a second input from an alternator or is the diode thingy capable of running with both alternator connected to the top bolt?

No second input Sandy. The diode wouldn't necessarily care, or know, how many alternators were connect to the top stud, but the alternators would.

The only feasible way to have both alternators charge both batteries would be to fit 2 diodes (or a different device). Looking at the OPs voltage readings it's very unlikely that he has a second diode.

Although some of the readings are odd (if they are correct), it's looking like there is too much voltage drop across the diodes, so all the batteries are getting is a float charge from the Stb alternator.

 

[Sandy]

No second input Sandy. The diode wouldn't necessarily care, or know, how many alternators were connect to the top stud, but the alternators would.

The only feasible way to have both alternators charge both batteries would be to fit 2 diodes (or a different device). Looking at the OPs voltage readings it's very unlikely that he has a second diode.

Although some of the readings are odd (if they are correct), it's looking like there is too much voltage drop across the diodes, so all the batteries are getting is a float charge from the Stb alternator.

Thanks @PaulRainbow always good to see somebody who does this for a living share their knowledge.

 

[PaulRainbow]

Thanks @PaulRainbow always good to see somebody who does this for a living share their knowledge.

Always happy to help Sandy