Battery switch

D

dotnmarty

New member
Our 16 footer has two batteries, one a deep cycle and one, well, not a deep cycle. The battery selector switch is in a rather inaccesible place behind the two batteries. My questions are these,
1. Is there a proper way to select the batteries (like battery one for starting, then switch to 'both')?, or
2. Can I just leave the switch on 'both' all the time and forget about it?
3. Should I move the switch, and, if so, where to on a 16 footer?....

Thanks
 
If you google in Battery Switch in the Search the C-Brats box, up comes a lot of the answers you are looking for. Hope this helps.

Martin.
 
Hi Martin-
You're kidding, right? I did what you said and suffice it to say, I still don't understand. Perhaps I should just ask my question number two...

2. Can I just leave the switch on 'both' all the time and forget about it?

Thanks
MartyP
 
My boat was originally set up that way and I always left the switch on 2 (house battery). This worked fine and I never wound up with a dead battery.

The danger with using the 'both' setting is you could drain both batteries and have no way to start the engine.

I recently had a Blue Seas voltage sensitive relay installed. Now I just turn a single switch to ON and the engine automatically uses the starting battery to start, then charges it to a certain voltage before switching charging over to the house battery. Easy and the best solution in my opinion.
 
Batteries and motor alternators are not happy campers if you are tying two batteries of different types together. It confuses the charging system, and one of the two batteries is not going to last, or at least will not be optimally charged. The voltage sensitive relay is the solution. If I were in your shoes I'd get two identical batteries and leave the switch on one or the other so you don't end up with two discharged batteries. You should at least relocate your battery switch to a readily accessible place. You can use two deep cycle batteries or two starter batteries. YES, deep cycles will start modern motors with little negative effect. Also, starter batteries will function as a house battery as long as you don't "deep discharge" it often. So, if it were me I'd be using two new identical deep cycle batteries with a relocated switch, or, do it right and get the voltage sensitive relay.
 
OK- I think I've got it, for now at least. I'll use one battery at a time, and if one dies I'll replace it with the same type as the remaining good battery. Then, perhaps, in the future, have a Blue Seas voltage sensitive relay installed. Thank you for your advice.
MartyP
 
Marty,
I have a two battery system. When I am running the boat I set the switch on 1&2 to charge both batteries. If I am connected to shorepower I leave it the same and let my onboard charger charge both batteries. When I anchor I switch to the house battery only so I have power for my lights, inverter etc. Then in the morning I switch to the start battery if the house won't start the boat. But so far the house (deep cycle) still has enough juice to start the engine. That the way I roll with my batts.
D.D.
 
The switch that I have in my boat has "Lock/Off", "1", "All", and "2" positions. When I picked up the boat, the dealer told me never to use the "All" position to charge both batteries at the same time. He told me that the two different batteries would not charge properly. I have never used the "All" position. What I do is always leave home with both batteries fully charged. When I arrive, I start the boat with battery "1" and do not touch the switch. If I stay overnight without shorepower, I use battery "2" as a house battery. I have stayed out two nights out without recharging and I normally run all lights in the cabin, a small DC fan, and a C-PAP with a DC converter. Never had an issue. When I leave the anchorage, I start the engine with battery "1" and immediately switch to battery "2" to recharge it.
 
Marty, a pertinent question that has not been asked. Do you spend the night on the boat and are you likely to run one/two batteries down when you do with the motor not running?

I think, knowing you, that the answer is no, you just use it for day trips. In that case, I'd just alternate the battery for each trip, use #1 first and then use #2.

If you and Dot spend a couple of nights on the hook at a time, start it with both, run it with both and then, when at anchor, switch to the house battery. That way, when you wake up in the morning with a dead house battery, you can start it and get home! That's the way we always did it but we haven't spent many nights without shore power available.

Ramon is correct however, if they are two different type batteries, they should not be charged in parallel. That way, they may only last 3 years instead of 4. They make VSR's for that purpose and special switches that will disconnect a battery when it's in parallel and fully charged. A whole new topic...

Charlie
 
It is starting to come clear now. Frankly, I very seldom spend the night on the boat, one or two nights a season maybe. Dotty and I just use the boat for day trips. We have no accesories run off the battery with the engine off except a phone charger and a second VHF handheld radio. Our heat, when needed is from a propane Mr. Buddy and our stove is a single burner Coleman propane. Cabin light, when necessary is from a small LED flashlight. So, I will do as suggested, one battery at a time, alternating batteries. The only bad thing is I have been trickle charging the batteries with the switch set on "both". I'll discontinue that now. Thanks.

MartyP
 
Marty, Sounds like you are on the right track. (I have 2 batteries that are the same and run in the "both on" position except for over night, where I do odd and even depending on the date.)

Just wondering if there is an easy way to turn that switch, like a special tool, (PVC pipe cut to fit the handle, or a piece of dowel and a notch in the switch or something). That might work easier than moving the switch. As to charging the two at the same time, I think that might not be the best idea, as previously stated.

Best, and enjoy,

Harvey
SleepyC :moon

Friends_Cal_09_10_Oct.thumb.jpg
 
He told me that the two different batteries would not charge properly.
Click to expand...

By "different", do you [all] mean deep cycle vs starting? I just bought a Dyno deep cycle 31 for our "house", so I'm curious of the answer. May be time to install that Blue Sea switch/relay.
 
The Dyno has so many more amp hours than the starter Interstate did. We wanna do some longer trips and I felt we needed more reserve for the house. Time for the Blue Sea....
 
If you are going to install two batteries and EVER charge or use them in parallel, they really must be the same type, two deep cycles or two start types, further they need to be the same make and model, and further, if you mix a three year old and a new battery of the same make and model, you will knock of life of the newer battery. So the only solution really, is to buy two new batteries, same make and model if you stick with parallel operations for use and charging. Now, that is the rule, but I, and others have violated that rule, but the statistics don't lie about what is best for the batteries. Not necessarily the short term affects on the pocket book.
 
Hi Marty,

My two cents worth... Move the Battery Switch to a readily accessible location. I set my boat up with #1 being the starting battery, and #2 as the house. After starting the boat, I recharge #1. If the house battery has been used, I will recharge it for a while. I never leave the switch in both for the reasons mentioned above.

Steve
 
I hope this is on topic enough for this thread... I have two Interstate batteries, one group 24 cranking and one group 27 deep cycle. They are 5 years old and need replacement.

I am thinking of switching to a matching pair of Interstate SRM-24s, and while I'm at it, I will likely be replacing the battery switch with a Blue See Add a Battery system:

westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10001&partNumber=8646275

This seems like a very simple solution, even more so than adapting my setup with a stand alone VSR. One thing that confuses me is that people have said a switch like mine (Guest 1-both-2-off) could be substituted for the Blue Sea switch from that combo. I don't see how since with my switch (I believe) you are selecting a battery for cranking and house power -- the same battery! With the add a battery setup it looks like house runs on the house battery, the motor starts from the cranking battery, unless you select BOTH in an emergency. Essentially they would be isolated, and my systems aren't!
 
localboy":188n4ysg said:
Read Greg's post about half way down.

http://www.c-brats.com/viewtopic.php?t=16347&highlight=blue+sea
Click to expand...

I was actually looking at that before I posted. But I don't think my switch will work... As far as I know my switch takes two batteries as input and has one output that fans out to the motor and house panel. That means the house and motor are connected to each other on the output, and are driven by battery A, battery B, both or neither.

The Blue Sea setup with their switch seems to keep the house and motor connected to separate batteries. The only interaction between the two happens during charging.
 
First, after looking over this thread I did not want to be providing bad advice. I should have realized everyone’s boat might be set up a little different. What we do based on the way our boat is setup might not be the best thing for someone else who’s boat is configured differently. Our boat was setup with two of the same type of batteries with a simple two battery switch Off /one on/two on/one and two on. We use a pair of Interstate deep cycle group 27 batteries. My motive has always been to keep everything as simple as possible while still getting the job done. Our boat came with a shore power and onboard battery charger standard. When the boat is not in the water it sits in the driveway with shore power connected powering a small electric heater and the on board battery charger is left on. We are going into our fourth year with our boat with the same original batteries. I service the batteries every year in the spring. They take some distilled water and I use petroleum jelly on all the connections. We spent about 50 nights sleeping on our boat last year and trailered it about 10,000 miles. So far so good. For me battery life I rate at five years. At the end of next year I’ll consider replacing my batteries with some Sears Deep Cycle Diehard marine batteries which are in the hundred dollar each price range. They have gotten decent reviews on Hull Truth etc.
See them www.sears.com/diehard-marine-deep-cycle ... 827524000P Two of my previous boats a Scout 18’ Center Console and a 24’ Grady White Offshore were rigged the same way as our C-Dory. We always used two of the same batteries and the same simple two battery switch. Because I carry a generator on extended cruises I can always use the generator connected to shore power to charge batteries if need be. Our normal power consuming devices are a 400 watt inverter that powers a wireless internet router with cell card, cpap machine an LED all around light at night led cabin lights, an Espar D 2 diesel heater, laptop, IPad, GPS on anchor watch it we are not at the dock. I have always been able to do overnightners so far at least using one battery and still been able to start my engine without having to switch to the second battery. So for me at least I don’t really see the need to rush to buy a Blue Seas voltage sensitive relay. If someone were to replace one battery they could just charge them individually not on both. For me though I have always replaced the batteries in pairs. Having two different batteries was not for me either. I guess there is some savings in dollars having a smaller start battery but in the economic context of boat ownership I say REALLY? That savings is then spent on the voltage sensitive relay? So if you avoid parallel charging is there really a need for voltage sensitive relay? Not trying to be argumentative; just trying to understand the need for setting up a boat this way. Is there a problem with a standard on board charger if your batteries are the same or different types or can the on board battery charger sense the voltage of the batteries separately ? Just wondering?
D.D.
 
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