Balmar SG200 Issue

[garmstro55]

My Mainship 400 has two engines and two 8D batteries. Each engine has it's own starting battery and the house loads are split between the batteries. I don't like this setup but that's what the factory did.

I installed the Balmar SG200 on the port side battery which, in addition to starting the port engine, has the refrigerator and some other house loads.

After installation at the marina it worked perfectly. I went for a ride and anchored down river for the afternoon and when I went to start the engines, the port wouldn't start without using the parallel switch. I thought maybe a weak battery but when I got back the the marina, I took the shunt out of the circuit and the engine fired right up.

This scenario repeated a few more times. It seems that something is causing the shunt to stop the electric flow to the engine after one of these trips.

Is it caused by the act of starting the engine? Is it caused because I used the windlass to lower the anchor? The engine started ok at the dock so something during this short run down river is causing this to happen.

BTW, I had anchored for 3-4 hours before I tried to start again so if something overheated I would figure it had cooled down in that time.

I eventually replaced the battery to see if that was the issue but got the same result.

Bottom line is the Balmar works fine at the dock when I put the shunt in the circuit but after a run down the river and an anchorage it won's start the engine unless I remove the shunt from the circuit. (I doubled checked and I do have the shunt wired with the correct lugs going to the correct side of the battery)

Any thoughts on why this might be happening or other tests/experiments I can do to try and troubleshoot?

One more detail: the shunt has threaded lugs and the battery terminal that goes to it has a battery terminal clamp connection. I bought a "screw-on" battery post that I threaded onto the lug of the shunt to make the connection. Maybe that's the problem but I can't imagine how.

 

[Comodave]

I don’t like those battery terminals, much rather have ring connectors. Much better connection IMO.

 

[rgano]

Did you happen to note the state of charge indicated on the SG200 before attempting to start after hours at anchor?

 

[garmstro55]

I don’t like those battery terminals, much rather have ring connectors. Much better connection IMO.

I am not a big fan either but I didn't want to change the termination going to the negative battery connection to a ring terminal until I proved the set up worked. Here is a photo of the setup.

The yellow wire came off the negative battery terminal and the black wire is the jumper from the shunt back to the battery.

The yellow conductor is larger than the jumper I had so I thought that could be the problem but it's only about a foot long so I didn't think there was going to be too much resistance. And anyway the boat started fine in the slip. I ended up going to a larger jumper not pictured and that didn't help.

 

[garmstro55]

Did you happen to note the state of charge indicated on the SG200 before attempting to start after hours at anchor?

I didn't notice it Rich. I think I am going to re-connect the shunt in the slip and see if I can replicate the behavior, i.e. turn off shore power, run the windlass, etc.

 

[rgano]

I didn't notice it Rich. I think I am going to re-connect the shunt in the slip and see if I can replicate the behavior, i.e. turn off shore power, run the windlass, etc.

Took the recommendation right outa my mouth.

 

[garmstro55]

Took the recommendation right outa my mouth.

Great minds....

 

[catalinajack]

Took the recommendation right outa my mouth.

Isn't that shunt just a glorified busbar with a gizmo attached on the side to measure current? I rather doubt it is a bad shunt. Something else going on there. I could be all wrong.

 

[garmstro55]

Isn't that shunt just a glorified busbar with a gizmo attached on the side to measure current? I rather doubt it is a bad shunt. Something else going on there. I could be all wrong.

It is kind of a busbar, I guess. This shunt apparently contains the brains of the device, so I'm told. I sent the shunt back and got a new one just to make sure and the same result.

 

[ssobol]

I doubt that the Balmar shunt is capable of switching the current or voltage flow on and off to the battery.

 

[Flatswing]

1) When you are at the dock, is your battery charger always on? What Amps are shown on the SG 200 at the dock?
2) With battery charger off/unplugged from shore power, and engine running, use a DC clamp meter to ensure your Port engine alternator is actually charging. (The SG 200 gives you a clue also, it shows the net of Amps supplied by the Alternator &/or battery charger minus Amps consumed by whatever is switched on)
3) Check for any voltage drop across the shunt.

 

[Bacchus]

Gary
I am not an expert on shunt based monitors so take my comments as food for thought rather than knowledge.
I have not seen shunt based monitors used on starting batty applications... only house type loads. I had one on a motorhome house bank and is my only reference. Might be worth a call to Balmar just to confirm that application is fine.
I too had 2 8D house / start bank on my single scrrew 2008 MS 34HT and never liked that arrangement. A change I made was to move start over to my 8D thruster bank which shortened the cable run by at least 50% and left my house bank a pure house. I also installed a Balmar Smart Gauge but it is the original SG w/o the shunt. I monitor house with it and the thruster V only as the secondary bank. I'll be watching your thread to learn... hope you work this outneasily.

 

[ssobol]

... based monitors so take my comments as food for thought rather than knowledge.
I have not seen shunt based monitors used on starting batty applications... only house type loads. I had one on a motorhome house bank and is my only reference. Might be worth a call to Balmar just to confirm that application is fine. ...

I use my SG200 on the start circuit on my boat (it does not have separate systems, just two switchable batteries). If the battery voltage gets too low during a start it will reset the SG200. The SG200 will not lose the settings when this happens, but can lose the current state of the battery. However, this does not prevent the engine from starting. The SG200 figures out the state of the battery again about the time it is recharged by the motor alternator.

 

[garmstro55]

Gary
I am not an expert on shunt based monitors so take my comments as food for thought rather than knowledge.
I have not seen shunt based monitors used on starting batty applications... only house type loads. I had one on a motorhome house bank and is my only reference. Might be worth a call to Balmar just to confirm that application is fine.
I too had 2 8D house / start bank on my single scrrew 2008 MS 34HT and never liked that arrangement. A change I made was to move start over to my 8D thruster bank which shortened the cable run by at least 50% and left my house bank a pure house. I also installed a Balmar Smart Gauge but it is the original SG w/o the shunt. I monitor house with it and the thruster V only as the secondary bank. I'll be watching your thread to learn... hope you work this outneasily.

Don, I was going to re-wire to have a separate house bank like you did but the forward A/C went kaput so I had to spend the money on that item which was a higher priority. I did talk to the factory and they said having it in the start circuit wasn't a problem. Based on the behavior I am seeing I have to wonder about that answer. What puzzles me is that the engine starts fine at the dock, then wont start when I'm ready to go home, but after I have removed the shunt and then put it back in the circuit, the engine will start fine at the dock again. Almost as if the shunt has re-booted or reset after having been powered down.

Once I have the time I going to experiment at the dock to see if I can duplicate this behavior.

 

[garmstro55]

I use my SG200 on the start circuit on my boat (it does not have separate systems, just two switchable batteries). If the battery voltage gets too low during a start it will reset the SG200. The SG200 will not lose the settings when this happens, but can lose the current state of the battery. However, this does not prevent the engine from starting. The SG200 figures out the state of the battery again about the time it is recharged by the motor alternator.

This is good to know. I figured there must be some boats out there with a single battery for both house and start.