Battery Switch Operation

seadaddler · Jul 23, 2012

Wow

What I did my 2007 H-36 which you may want to just add a manual off on battery switch fom my start battery to my house in my cockpit locker easy to get to and nice backup for sure.
Nick

Rick486 · Jul 23, 2012

Re: Wow

Marc:
2 things.
1. If the solenoid drops out when the start batt voltage is low, why even have it in the design? It seems that the solenoid is there to ensure you can always start the Yanmar or the genset, even if the start battery is kaput.

2. Looking at the schematic in my owner's manual, it looks like the solenoid is powered closed when you turn the key at the engine panel. If the red barrel switch for the start battery is in the OFF position, it looks like the house bank voltage is to the starter and will start the Yanmar. I'm not at the boat at the moment but will try this tomorrow.

It seems a puzzle why your friend's start battery died.

onecoolair · Jul 23, 2012

Marc14857 said:
We were out on moorings adjacent to friends on a 2006 H41 last night when I got a call from them to see if I could bring over my start battery as theirs was dead and they could not get the engine nor the generator started. Their house bank appeared to be fine but we could not come up with a means short of jumper cables to line up the house battery to the starter.

I've got the exact same configuration on my boat and was wondering if anyone could verify my understanding of the circuit. (SEE ATTACHED SCHEMATIC). Each battery has its own selector switch with an on/off position. It appears to me that the house and the starting batteries are cross connected via the Cole Hersee solenoid, which is designed to be normally energized. I assume that the solenoid remains energized as long as the start battery voltage is above the drop out voltage for the solenoid. Once the voltage in the start battery decreases the solenoid deenergizes isolating the house battery from the start battery. Once that happens there is no way to switch the house bank over to start the engine. Does this make sense? If so I'm not sure why we didn't have sufficien voltage in the starting battery to start the engine short of a catastrophic failure of the starting battery which may have been the case.

Ultimately we disconnected his start battery and used mine to get the Yanmar started. We disconnected my good battery and the Yanmar as expected continued to run and he was able to get back to the marina.

Just want to make sure we did not miss anything.

Thanks
Marc

Are you sure the starter battery was dead? I had a problem for a long time. It started sometime after about a year from new. Sometimes the yanmar would start and sometimes it would not. All the batteries had plenty of juice. It got to were to start the yanmar I had to start the generator turn the battery switch to all. Turn the battery charger on and wait a few minutes.
Turned out it was in the defective yanmar wireing harness. Found cleaned and redid all the hidden plug connectors on the harness. Found over priced yanmar key switch to be defective. Replaced key switch with a new brass model from o'reallys about 20 bucks. But still to no avail. Showed good volts at yanmar instrument panel. Finially ran a new properly sized momentery continouis white wire along harness to starter seloinoid. Problem solved! It seems the white wire in the harness would show volts but when asked for an amp load if would fail.
I now have a selector 1/2/both switch for starter battery and can switch to house bank main 1/2both switch and have a by pass starter button next to engine. I also moved starter battery closer to engine. Now that battery is not 15' away. Well Actually it was more like a total of 30 feet away. Battery to selector switch "C" post then back to starter another 15'.
Now battery cable from starter battery is only about 5 feet to 1/2both on off selector switch next to engine.
The routine now is to open engine compartment inspect engine turn on battery switch to starter, when done at end of day inspect engine turn off battery to starter.

Don12364 · Jul 23, 2012

Marc,
I have a similar relay. It is a heavy duty simple combiner and a very good thing too IMHO. I do not believe it is in some automatic system that measures voltages and either connects or not depending upon state of charge.

However the coil will draw about 200mA so it is unlikely that it will be ON all the time as this would be an unacceptable constant drain. It comes in when the engine keyswitch is ON so that both the engine and the house batteries get charged by the alternator. This also means it comes in for every start which is not such a bad thing either.

Some will argue that a low house battery will drag the engine battery down. But I notice that any battery on charge immediately jumps up in voltage by about 1½ volts so it doesn't really load the good battery.
Of course a failed battery with a dead cell will drag a good one down but only IF that cell has an internal short
My batteries last for years anyway and I am still on my first engine batty since 1996.

Rick D · Jul 23, 2012

Had This Happen Once

I had the start battery tank after the boat had been in the yard. The staff left the ignition switch on for 200 hours and the start battery failed. There is no way to combine the start and house banks in my boat which relies on a battery isolator (Sure Charge) to take care of that task which it also did in this case since the house batteries were perfect. Only no way to combine them for starting. Borrowed some jumper cables.

More recently, my sense wire to the external regulator was accidentally cut and thus the alternator would not charge anything. I thought it was the isolator since the lead to the house bank was a tad crispy and the stud fell out when I tried to unscrew the nut. So, I ordered a new one but got in a hurry when heading out for a trip and got another from a local electrical place.

So... if anyone wants a new Sure Power isolator cheap, check out e-bay.

But the point of this is that short a total failure of the start battery, this set up is just fine. My first start battery went 10 years and might still be going at 18 if it hadn't been for the yard error.

Schatzi · Jul 24, 2012

Marc:
I was concerned about the same and sent the following to Hunter Re: changing out the switch to allow for start from the house batteries. It seems to work well now that I have made the change.
...............................
I have a question about my 2003 Hunter 44AC. Can you point me in the right direction?
The battery switch selections are a Blue Seas Panel with On/Off for the Engine Start Battery and for the House Batteries. This configuration does not allow for me to use the house batteries if I would run into a problem with the engine start battery. It seems that an easy solution would be to replace the engine start battery on/off switch with a off/1,2,1+2 switch and pull a lead over from the house switch to land on the 2 terminal. The question I have is: If I do this, will there be an opportunity at any time to short something if the new switch is left on 2 or 1+2? Will the battery charger, alternator…etc work without possible problems?

Answer from Hunter:
Spoke to our system person…based on your information he doesn’t see a problem.
Thanks, Eddie Breeden
.......................................................
Hope this helps!

captainpat · Jul 25, 2012

I believe Rick486 is correct; the solenoid is energized at the turn of the ignition key and functions as sort of an isolator/combiner. When starting, both banks are joined, also allowing both banks to be charged while running. I had charging problems recently on my 426. When running, the house bank was getting very little charge - 12.4!! while the start bat was getting 14+. The solenoid had to be replaced. Simple job.

Maine Sail · Jul 25, 2012

Marc14857 said:
Each battery has its own selector switch with an on/off position. It appears to me that the house and the starting batteries are cross connected via the Cole Hersee solenoid, which is designed to be normally energized. I assume that the solenoid remains energized as long as the start battery voltage is above the drop out voltage for the solenoid.

These solenoids are engaged by the ignition/alt circuit. Turn off the key and the solenoid breaks. They are also undersized for the potential loads they may see especially when an owner does an alt upgrade.. A true ACR or VSR would make break via voltages automatically and also isolate the relay during starting via a start switch on terminal. This is to prevent burning up the solenoid by pulling starting, windlass or other high amp loads through it. I have had to replace a few of these and feel an ACR with start isolation is a safer and longer lasting device. In both cases the owners had added larger alternators. The other problem is that with an external charging source like solar or wind the batteries remain isolated unless the key/engine is on, so no charging to one bank unless the key is left on. If you have a bank failure there is no way to "isolate" the banks when the key is ON short of unwiring the solenoid circuit or breaking a fuse/breaker.

Marc14857 said:
Once the voltage in the start battery decreases the solenoid deenergizes isolating the house battery from the start battery.

It does not do this based on voltage it does it based on the ignition key and the alternator...

Marc14857 said:
Once that happens there is no way to switch the house bank over to start the engine. Does this make sense?

There is no "switching over" to anything with this wiring design unless you add a switch to it. IMHO it is a pretty poorly executed system unless everything always works perfectly, which on boats does not always happen. It no doubt saved Hunter a few pennies..

You could add a third "emergency" combine ON/OFF switch. If the switches are wired correctly it can allow for full isolation of a bad bank and allow the entire system to run of either bank.

Marc14857 said:
If so I'm not sure why we didn't have sufficien voltage in the starting battery to start the engine short of a catastrophic failure of the starting battery which may have been the case.

Well when one bank gets low and that solenoid is engaged it tries to pull the entire starting load through that circuit. Not a good idea. These solenoids are really not intended for that type of load and can fry, as I have found. Max continuous is 65A and many of these boats have charging systems and battery banks and loads that can easily exceed 65A continuous. They can do upwards of 750A for 10 seconds but then must remain OFF for 30 minutes otherwise you'll cook them. A few tries to start the engine and you can cook them pretty quickly. This is why Blue Sea has the Start Isolation feature on their relays...... Hunter probably paid about $20.00 for that relay vs. a cost of about $60.00 to a builder for an ACR... Those pennies add up....

Marc14857 said:
Ultimately we disconnected his start battery and used mine to get the Yanmar started. We disconnected my good battery and the Yanmar as expected continued to run and he was able to get back to the marina.

Just want to make sure we did not miss anything.

Thanks
Marc

Turn the key on, start engine, and measure continuity across the two large studs on the solenoid. This circuit is tied into the alternator alarm circuit so engine should be on and key on. Better yet replace it with a Start Isolation ACR (voltage sensitive relay) and let it be fully automatic or add a third battery ON/OFF switch for manual configuration in emergencies.

Rick486 · Jul 25, 2012

Me too

Marc14857 said:
I am at the boat now and did just verify with the start battery switch off and house bank switch on, there is no power available to the starter. Based on the the various posts I am leaning toward replacing the existing battery on off switch with a battery 1,2, off switch where i can select to power the starter from the house bank if necessary as Schatzi describes.

Yes I also verified this morning that with the START bank switch in the OFF position there is no voltage to the engine panel and thus I cannot start the engine, or presumably the genset but I didn't try that. So it appears that the solenoid is energized from the ignition switch and remains closed so long as the ignition switch is ON and has power. It also appears that the engine panel is energized ONLY by the START batt when in the ON position. It was clear from my poking around today that if the HOUSE bank switch is in the ON position with the START bank in the OFF position the engine panel is dead. Interestingly, there is a small note in my user's manual recommending that the HOUSE bank switch be in the OFF position during start, then rotated to ON after the engine is running.Thus as several folks have said above, the HOUSE bank and the START bank are paralleled during start, and while the engine is running (ignition switch ON) since the solenoid is a continuous duty component, which facilitates charging of both banks by the alternator on the engine.

All of this leads me to suggest that there may be a simpler, cheaper solution to the issue of stating the engine when the START batt is dead. It would seem that what is preventing that evolution in our current design is that the 12 volt supply for the engine panel comes only from the START bank. So why not identify the supply wire to the engine panel and simply splice a low amp lead from the HOUSE bank switch into the engine panel supply. That way the panel sees 12 volts when either bank in ON. I'll run this by Hunter.

Rick486 · Jul 25, 2012

OOps - mea culpa

Rick486 said:
Yes I also verified this morning that with the START bank switch in the OFF position there is no voltage to the engine panel and thus I cannot start the engine, or presumably the genset but I didn't try that. So it appears that the solenoid is energized from the ignition switch and remains closed so long as the ignition switch is ON and has power. It also appears that the engine panel is energized ONLY by the START batt when in the ON position. It was clear from my poking around today that if the HOUSE bank switch is in the ON position with the START bank in the OFF position the engine panel is dead. Interestingly, there is a small note in my user's manual recommending that the HOUSE bank switch be in the OFF position during start, then rotated to ON after the engine is running.Thus as several folks have said above, the HOUSE bank and the START bank are paralleled during start, and while the engine is running (ignition switch ON) since the solenoid is a continuous duty component, which facilitates charging of both banks by the alternator on the engine.

All of this leads me to suggest that there may be a simpler, cheaper solution to the issue of stating the engine when the START batt is dead. It would seem that what is preventing that evolution in our current design is that the 12 volt supply for the engine panel comes only from the START bank. So why not identify the supply wire to the engine panel and simply splice a low amp lead from the HOUSE bank switch into the engine panel supply. That way the panel sees 12 volts when either bank in ON. I'll run this by Hunter.

Something Maine said above just clicked with me. In the workaround I described above, the solenoid will see full start amps whenever House bank is chosen to start the engine. May not be good with the 65 amp cont rating of the solenoid. Now I think I understand why Hunter recommends setting the HOUSE bank on OFF prior to start. I just don't like the idea of dumping that load on the alternator while it is running loaded only by the START Batt.

Ron McCoy · Jul 25, 2012

I'm not on your boats, so I have to rely on how my H386 is set up. Here goes.
If the start battery is truely dead you can still start the diesel with the house battery. Some of you have come close to the solution, but there's something you've missed.
Turn ON both the start and house battery switches. Then, put the key in the ignition. When you go from ON to START, the solenoid that links the two battery switches closes. This allows current to flow from the house battery switch to the start battery switch and consequently to the starter. Once the key is returned to the ON position (after the engine starts), the solenoid disconnects and thus isolates the start battery from the house battery. Hopefully the alternator is working properly and reenergizes the start battery (if it's not destroyed earlier). It's that simple.

Rick486 · Jul 26, 2012

Ron McCoy said:
I'm not on your boats, so I have to rely on how my H386 is set up. Here goes.
If the start battery is truely dead you can still start the diesel with the house battery. Some of you have come close to the solution, but there's something you've missed.
Turn ON both the start and house battery switches. Then, put the key in the ignition. When you go from ON to START, the solenoid that links the two battery switches closes. This allows current to flow from the house battery switch to the start battery switch and consequently to the starter. Once the key is returned to the ON position (after the engine starts), the solenoid disconnects and thus isolates the start battery from the house battery. Hopefully the alternator is working properly and reenergizes the start battery (if it's not destroyed earlier). It's that simple.

Maybe not Ron. You see, the engine panel is powered only by the START batt, so if the START batt is truly dead, you may not have sufficient voltage to power the ignition switch and hence the solenoid. This is exactly the point made by Marc in the original post. Perhaps Hunter designed the circuit this way to prevent starting amps from passing through the solenoid.

Maine Sail · Jul 26, 2012

Ron McCoy said:
I'm not on your boats, so I have to rely on how my H386 is set up. Here goes.
If the start battery is truely dead you can still start the diesel with the house battery. Some of you have come close to the solution, but there's something you've missed.
Turn ON both the start and house battery switches. Then, put the key in the ignition. When you go from ON to START, the solenoid that links the two battery switches closes. This allows current to flow from the house battery switch to the start battery switch and consequently to the starter. Once the key is returned to the ON position (after the engine starts), the solenoid disconnects and thus isolates the start battery from the house battery. Hopefully the alternator is working properly and reenergizes the start battery (if it's not destroyed earlier). It's that simple.

On the boats I've worked on the key turned on or energized the solenoid not the actual starting position. Anytime the key was on the solenoid was closed. On a couple of boats I have seen them utilize the alt alarm circuit with "key on" to engage. This method leaves you with no way to combine a bad battery and good because the engine has to be running first. These circuits are intended so that both banks get charged off the alternator but when bigger alternators are added owners need to do something different as the relay won't handle it.. I know in the past Hunter has suggested a diode isolator but there are better choices these days..

Rick486 · Jul 26, 2012

This has been a very informative thread. I'm going for the jumper cable as the KISS solution. Absent this thread I would have been up s***s creek without a paddle if my start batt ever went flat. I never would have been able to figure this out on the water.
Thanks everybody

heritage · Jul 26, 2012

Maine Sail said:
On the boats I've worked on the key turned on or energized the solenoid not the actual starting position. Anytime the key was on the solenoid was closed. On a couple of boats I have seen them utilize the alt alarm circuit with "key on" to engage. This method leaves you with no way to combine a bad battery and good because the engine has to be running first. These circuits are intended so that both banks get charged off the alternator but when bigger alternators are added owners need to do something different as the relay won't handle it.. I know in the past Hunter has suggested a diode isolator but there are better choices these days..

My RV uses a Cole-Hersee solenoid in much the same way that Hunter does. Except that the solenoid is activated (closed) by the alternator output. It is controlled by a fused small gauge wire from the output post of the alternator to the + post of the solenoid. So the solenoid never sees starting voltage. There is another wire to the + post of the solenoid and that is a momentary on thumb switch on the dash, called a boost switch, that combines the house and start battery banks, to be used only when the start battery is too low to start the engine.

The cheapest Cole-Hersee solenoids are prone to early failure because of pitting of the copper contacts due to high amperage sparks. The failures tend to be intermitant, because each time the solenoid is activated the loose footed contact spins a bit and may or may not come down on a pitted area. One solution is to change to higher amperage continuous duty solenoid that uses silver plated contacts. They are still fairly inexpensive as compared to ACRs.

But, I do think that the ACR, in the long run, is the best solution. Much easier to fit into the panel than adding manual on/off switch. Although, I suppose you would lose the ability to manually tie the batteries together.

Rick486 · Jul 29, 2012

I know we've beaten this one up pretty well but I have one nagging question I'd like to put out for comment.

My owner's manual recommends starting the Yanmar with the HOUSE bank switch in the OFF position, then switching to ON after the Yanmar is running. As a result of this thread I now understand why that might be a good practice as it precludes start current from the solenoid. OK, now my question is this:
Does anyone seen any potential issue associated with switching the HOUSE bank load into the alternator charging circuit with the engine running? Obviously Hunter thinks it's the proper procedure or they would not have recommended such, and I have great respect for their opinions. It's just that I have operated through 3 boats over 30 years believing that switching the batteries in and out of the charging circuit with the engine running was taboo.
Thoughts?

Battery Switch Operation

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