battery switch just throw it overboard!

[imported_DANA1]

i dont seem to understand the battery switch so heres what ive got would like your opinions. we have a 2 battery system one start battery deep cycle group 27 and two 6v deep cycle golf cart tied as 12v for house.

hear is typical use lots of start and stop while tubing then camp for weekend,no shore power so how should we be using switch so not to be stranded on sunday morning thanks.

 

[Dunaruna]

Re: battery switch just throw it overboard!

[colour=blue]A rotary battery switch (off/1/2/both) is the easiest option but there are others.

What motor do you have and more importantly - what charging system?

BTW, the 2 6volters are a great house system.

 

[imported_DANA1]

Re: battery switch just throw it overboard!

hello that is the switch im using for mercruiser 5.7 with a 55 amp alternator i just installed a prosport 12 amp smart charger and the batteries im talking about,so havent even had a chance to try them out yet . wanted to correct my knowlegde on a few things that i dont really understand. thanks

 

[Silvertip]

Re: battery switch just throw it overboard!

The only setting you DO NOT want to use with the engine running is OFF. That will kill the alternator in a heartbeat. You use that setting when the boat is on the trailer or docked and you hopefully have the bilge pump(s) wired directly to either battery. Here are a few scenarios:

Engine Start:
Switch to the START battery. That will be "1" or "2" depending on which switch position its wired to. IF you ever have dead START battery, switch to the HOUSE battery. When the engine starts, switch to BOTH.

At Anchor:
Stop engine and switch to the HOUSE battery. This disconnects the START battery so you won't run it down.

Engine Re-start:
Switch to the START battery. When engine starts switch to BOTH to charge both the house and start batteries. Or, you can switch to the HOUSE batteries to allow them to receive the full charging system output.

Look at the switch as a water faucet. You either want hot water, cold water or a combination of both. "1" charges the start battery. "2" charges the house battery(s) "Both" charges both. You either charge the batteries (when running) or you draw from them (when parked).

 

[imported_DANA1]

Re: battery switch just throw it overboard!

thank you, my next question is if i dont want to lift engine hatch 15 times a day could i use an isolator on start batt then just run both all the time and the isolator would prevent the start batt from dropping below starting capacity do i understand this correctly?

 

[Silvertip]

Re: battery switch just throw it overboard!

Sounds to me like you want the versatility of the battery switch with the "no bother" feature of an isolator. The isolator prevents drawing "house power" from the start battery and vice-versa. It has no switching capability. Lose the start battery and there you sit unless you have a pair of jumper cables. It seems like you are already confused by the switch so you are making the situation even more complex if you incorporate an isolator. That combination seems counter-productive but I've not given it much thought. If access to the switch is a problem, why not relocate it?

 

[RV-Dean]

Re: battery switch just throw it overboard!

There is a Solenoid system in the RV world (I had one) that would route charging power from the alternator to the chassis (engine) battery and the coach (Hotel) batteries or just the chassis battery its control voltage came from the chassis battery. My Chassis battery was a 12V designed for cranking the 454. My coach bank was a pair of 6V Trojans, T105’s. The battery switch would charge both but only crank from the chassis battery. There was another solenoid with a separate control switch that I could hold the switch in a momentary position and it allowed starting the engine from the coach batteries basically jump starting yourself. Control voltage for it came from the coach batteries. Very simple system that allowed you to charge hotel without generator or shore power, jump engine from hotel and even jump generator from chassis battery (generator by default started from hotel batteries). This system also protects the engine battery from discharge from hotel loads while the engine is stopped because its control voltage comes from the alternator and would open the Solenoid to the hotel bank when the engine was not running. These solenoids are a second party system to the RV manufacturers and are very common. I can see no reason why you could not use them to solve your desires.

 

[imported_DANA1]

Re: battery switch just throw it overboard!

thanks guys ill give all the info some thought

 

[bruceb58]

Re: battery switch just throw it overboard!

RV-Dean is describing the RV equivalent of the marine combiners or ACR(Automatic Charge Relay). Blue Sea make excellent ones that are current limiting and have adjustable voltage thresholds.

http://bluesea.com/category/2/productline/236

 

[Zim]

Re: battery switch just throw it overboard!

Where can one of these switches be picked up, and anyone know off the top of their head what amperage the alternator has on a 4.3L merc?

 

[Nova II 260]

Re: battery switch just throw it overboard!

Always carry a jump start pack just incase.
It'll also gets "free beer" at the launch ramps.
d

 

[bruceb58]

Re: battery switch just throw it overboard!

A "jump start" is going to have a very tough time jump starting a V8 with a totally dead battery.

 

[Zim]

Re: battery switch just throw it overboard!

A "jump start" is going to have a very tough time jump starting a V8 with a totally dead battery.

It shouldn't.... my jump box has started my v8 mustang cobra on more than one occasion when even the dome lights wouldnt turn on. I dont see why it would be any different on a boat. Starting amps are a good thing.

 

[bruceb58]

Re: battery switch just throw it overboard!

Very small battery with a very low guage wire is the problem.

 

[Aquaman]

Re: battery switch just throw it overboard!

Very small battery with a very low guage wire is the problem.

I use mine every time a "no start" is towed into my shop. A decent "jump box" can start a vehicle 8-10+ times before needing a recharge. I've even used mine to start vehicles that didn't even have a battery.

As with anything poor quality can yield poor results.

 

[bruceb58]

Re: battery switch just throw it overboard!

The shop jump boxes have normal size batteries in them. The "jump start" type are basically bigger versions of motorcycle batteries. The "jump start" boosters also only have 5 AWG wire vs what should really be closer to 2 AWG wire.

 

[Aquaman]

Re: battery switch just throw it overboard!

I don't use a commercial version,just a $125.00 box from a local parts store. Weighs maybe 10 pounds. After two years I replaced the batteries through my Interstate battery sales rep.

I have seen crappy versions that run from 35-75 dollars. Wouldn't trust them to start my mower. As with most things, you get what you pay for.

 

[Nova II 260]

Re: battery switch just throw it overboard!

Mine works for any dead batteries it has encountered in the past few years. It's a cheap one from Sam's club, but it works fine. It's been great for cold winter starts on some old V-8 irons I have in the driveway.
Remembering to keep it charged is the hard part.

 

[I/O WALDO]

Re: battery switch just throw it overboard!

5 AWG wire???