How to stop using battery selector switch?

[tedt]

I've searched all through the forums and see many posts on isolators and combiners, but I don't see anything that answers my question. I have a Hunter 340. The battery selector is mounted inside one of the lazarettes which requires you to practically climb in to actuate it. I would very much like to find a solution that will automate the battery switching, avoiding the need to use the switch regularly. Current setup is 1 starting battery on 1, 3 deep cycle batteries for house bank on 2 with a 1,Both,2 battery selector switch. It is necessary to switch to back 1 to start the boat and then back to 2 after the boat is started to prevent running the starting battery down...2 lazarette dives per start.

I have chartered boats for which everything runs off the house bank until you start the engine. As soon as the starter load is sensed, the starter battery is paralleled in and is re-isolated after the engine starts. It also automatically charges whichever bank requires it from either the alternator or shore power charger.
Does anyone have this kind of setup? What type of equipment do I need? I've talked with Hunter and a couple of the combiner manufacturers and either they don't have a product that does this or they don't understand me.

Thanks, Ted

 

[Maine Sail]

You don't need

You don't need to start the engine with the "starting" battery as your house bank has lots more capacity than you'll need. Starting an engine uses very, very little ah capacity. Starting my 44hp four cylinder Westerbeke takes less than .1 ah of capacity out of the bank. If you plug into a dock charger during the week just leave it on position 2, while away from the dock, and you'll be fine..

There are plenty of ways to reconfigure the wiring so you can charge both banks from one switch position. A charging relay like the Blue Seas ACR or the Xantrex Echo Charger are good options.

Try thinking of your starting battery as an emergency or back up battery only and not one you use on a regular basis. There really is no need to not start a small aux diesel with the house bank.

 

[Ross]

I set my battery switch on "both" or "off". When it is "off" I can't start the engine. So when I leave the boat the switch is "off" and the engine is locked up. For you I would simply relocate the switch to a more convienient location.

 

[Steve Dion]

We leave ours on the house bank all the time. The starter battery should be labeled as emergency only. I use the house bank for everything. Occasionally it is good to start the engine with the "emergency/starter" battery to make sure that it is operating properly.

If you system is wired properly you should be getting a charge from the shore power to all banks.

 

[tedt]

My house bank must be weak, because I cannot start the engine off of it almost all the time (yes, 3 new batteries is somewhere on my list)....Having said that, this is not a question of need it is a question of want. So...does such a device exist?
And,yes, charging is not the problem...managing the load to the appropriate bank without worrying about the switch position is the fundamental concern.

 

[Stu Jackson]

Try this

link: http://c34.org/bbs/index.php/topic,4949.0.html

We've discussed just what you've asked about, and you're right about searching on isolators and combiners. Try searching on "1-2-B switch" and "echo chargers' - many of us have written a lot here. The link above has other helpful links embedded.

 

[Maine Sail]

My house bank must be weak, because I cannot start the engine off of it almost all the time (yes, 3 new batteries is somewhere on my list)....

That is a major problem. Even a personal watercraft battery has sufficient cranking amps to start most small aux diesels and you have three large batts that can't. You could have a corrosion issue or a bad ground causing this too.

The first item I would suggest is to get yourself a good battery monitor. Your bank should not be drawn down below 50% on a regular basis. With a good bank and clean solid connections a bank of three deep cycles will start you engine with more oomph than you'll ever need.

Having said that, this is not a question of need it is a question of want. So...does such a device exist?

A device like that may exist but is unnecessary with a well designed and monitored system. I have never seen such a device and think perhaps you may be confusing what they have said happens. They are probably using a charging relay with a direct connected start battery. Once the engine starts the banks are automatically connected via the charge relay.

I have chartered boats for which everything runs off the house bank until you start the engine. As soon as the starter load is sensed, the starter battery is paralleled in and is re-isolated after the engine starts. It also automatically charges whichever bank requires it from either the alternator or shore power charger.

Paralleling in a fully charged battery, to a battery bank with less charge, especially a significantly LARGER bank, is not really a good idea. Battery isolators are also no longer used much because of the charge inefficiency and have been replaced by automatic charging relays or Echo type chargers. The low and larger capacity house bank can draw a significant amount of usable "start" current from the good one by paralleling. More than once I have heard of someone combining a totally dead house bank with a perfectly good start battery only to be left dead in the water..

And,yes, charging is not the problem...managing the load to the appropriate bank without worrying about the switch position is the fundamental concern.

Again with the appropriate system there should be no need to touch the switch other than to turn the system on and off and the emergency battery will always be charged and ready. Based on the fact that you can't start a small diesel with three batteries I think your best purchase would be to get a battery monitor first then deal with the switch wiring.

The most simple fix is to direct wire the alt to the house bank instead of the common post of the batt switch. By doing this you never again run the risk of frying alternator diodes by passing through the off position because the alternator now always sees a load. The start bank is then charged by an Echo Charger off of the house bank when it senses charge level voltages. You then just leave the switch in the #2 position all the time and both banks get charged via the alt when away from the dock without selecting the "both" position which is not a good choice due to human error.

If you can't start your engine off the house bank the issue is not the switch it's a battery management problem which a good battery monitor will help with..

 

[rardiH36]

You mention that the house bank won't start your engine. The batteries might be weak as you suspect, but Maine Sail also comments that not much Ah's are required to start an engine. Maybe instead (or at least a contributing factor) is that battery power isn't making it efficiently to the starter; which will be particulary noticeable if the batteries are weak as well.

If you haven't checked already, might be worth an hour or two to verify that all battery cables and their terminal connectors are in good shape (at the battery, at the switch and at the alternator), and that all fittings are clean and tight. This includes taking off the battery selector switch and checking the connections inside. You comment that your switch is mounted in a lazarette. This location might be subject to damaging moisture over the years, as compared to a switch mounted in the cabin. Just a thought.

Although I had read many times at how critical these aspects are to actually getting the batteries' cranking amps to the starter, a recent project rammed the concept home. Cleaning off years of built up oxidation at the terminals and then making somewhat loose connections tight again restored marginal cranking power to "vroom-vroom".

 

[Stu Jackson]

rardi's right, and: Don't forget the grounds.

 

[Maine Sail]

The Yanmar

The 1kw Yanmar starter on the motor in most Hunter 340's consumes a max of just under 225 amps at absolute peak load. Absolute peak load is usually less than a second or two.. CCA and MCA are rated at 30 seconds and 0 F and 32 F respectively before the battery falls to under 7.2 volts.

Even the smallest group 24 deep cycle marine battery sold by West Marine has 625 MCA and 500 CCA. Most boaters will never use the CCA rating as temps when were boating are usually not 0 degrees F..

Here's a video of a motor starting and the loads associated.. Video (LINK)

 

[Don12364]

Combiners?

The battery selector is mounted inside one of the lazarettes which requires you to practically climb in to actuate it. I would very much like to find a solution that will automate the battery switching, avoiding the need to use the switch regularly.

Okay so you don't like being a contortionist to get to the master switches. Also this setup increases the chance of forgetting to switch them off when leaving the boat.

If you left the main switch off and bridged the house side with a simple combiner (not an ACR) then fed the coil via a 5 amp fuse from the hot side of the house battery and brought a light gauge wire to a switch on your navigation panel - this switch making to the 0V side of the panel, then you will have the capability to switch the house bank on and off from the cabin. Having a 12V LED on this switch is also a good idea but will mean bringing a pair of wires from the lazarette, one from each side of the coil.

This leaves the question of charging the engine battery.
My boat (H376) came with a combiner which comes in to charge the engine battery when the ignition is switched on so yours might have one already. If not why not fit one which comes on via the ignition switch?

 

[Maddog]

Blue Sea makes a product for this. Look at the the eSwitch with an ACR. The eSwitch keeps the starting and house bank seperate. You can combine them for emergencies. Both circuits are either both off or both on. Use the ACR, a voltage sensitive diode that combines the banks when it senses a charging voltage on either side, 13.2v or above.

As mentioned above, hook it all up directly to the house bank. The ACR will take care of the start battery. The house will never drain the start and all will be happy.

As to the location of your current switch, be bold and buy a hole saw. Place it where you want.

 

[Bad Obsession]

Instead of spinning money on new switches, fancy battery adjusting systems, of any of the like why not just go to Wal-mart and pick up 3 new group 27 deep cycle batteries at a whopping $75 a piece. That will probably be the cheapest solution.

Moving the selector switch is a good suggestion too. With new batteries, clean terminals and grounds, and everything set up the right way, you will be good to go!

 

[Ed Caldwell]

Ted, I upgraded the switch/battery/charger setup on our H340 after a lightning strike forced the issue almost four years ago. See the link for pictures and descriptions.

I did not change the wiring to the alternator per the several posts above, so it still runs as per the factory setup to the switch for the "starting" battery (WM sealed 12v) and the combiner (ACR) takes care of getting the amps to the house batteries (T105s at 6v each) when charging off the engine. The Xantrex charger has separate feeds to each bank when charging off shore power. I never touch the battery switch.

The boat stays in a slip on shore power when not in use, so the batteries are always fully charged when we leave for a night on the hook, and the 225ah capacity of the T105s never gets more than 20% used overnight, even with refrig, interior lights and anchor light in use, with no attempts at conservation

I'm in the directory if you have specific questions.

http://hunter.sailboatowners.com/in...id=267&cat_id=32&aid=7457&page=article&mn=340

 

[tedt]

Thanks to all who responded. The responses from Maine and Rardi especially got me thinking "somethin' ain't right" so I went digging a little deeper this weekend. The prev owner had increased the house bank from 1 batt to 3 and had move them to the port lazarette. To do that he added an extension (aluminum terminals) from the existing battery cable (brass terminals) using a bolt. Not sure about the melaturgical implications of brass and aluminum together but I did find the connection to be quite dirty. Cleaning the contact surfaces with emery cloth produced a noticable improvement in the starter's ability to crank from the house bank. I'll probably see how this works for a while and if necessary buy a new cable to make the run from the selector switch to the house bank. I was able to start the engine all weekend without changing the selector from the house bank which is basically the outcome I was hoping for...

 

[Stu Jackson]

Combining bad & good banks is dumb

Blue Sea makes a product for this. Look at the the eSwitch with an ACR. The eSwitch keeps the starting and house bank seperate. You can combine them for emergencies. Both circuits are either both off or both on.

That is the dumbest electrical boat system idea I've ever heard of. There should be NO reason to ever have to combine batteries. Either one is good and one isn't and the only reason to switch batteries is because one's bad. Why would you ever want to combine a bad bank with a good one. The dual circuit switch concept is stupid.

See: http://c34.org/bbs/index.php/topic,4623.15.html

 

[Maddog]

Stu - Tell us how you really feel. They are only combined when there is a charge over 13.2v. Contrary to your opinion, it has worked very well for me.

 

[Blitz]

One question in the old battery switch debate I never see mentioned I was hoping somone would clarify: If you are using a combiner, with a battery charger with mulitple outputs should you still hook the charger up to the mulitple banks or let it spill over from the house to the emergency/starter battery bank?

 

[Don Crowther]

Ted

"he added an extension (aluminum terminals) from the existing battery cable (brass terminals) using a bolt"

I ws always told never ever have a mix of brass and aluminum fittings. They will corode and quickly.
Just my 2 cents worth.
Don