Battery Switch

wstokes · Post by **wstokes** » Tue Apr 18, 2006 9:18 pm

The existing battery selector switch failed today on my Rival 32. I have to replace it and I was considering buying a Blue Sea Parallel Mini Switch (the one with a separate switch for house and cranking batteries and an emergency switch for combining both banks. Am I making the right choice in choosing this type of switch device? I still use a "Dynastarter"-generator for starting the Volvo MDIIB engine and charging needs.I am not sure if these new style mini switches will allow me to charge both batteries at the same time. I normally only charge one battery at a time anyway. Any advice would be greatly appreciated.

Ric in Richmond · Post by **Ric in Richmond** » Tue Apr 18, 2006 11:09 pm

I am thinking of doing the same thing right now, is this the switch you are looking at?

http://www.bluesea.com/product.asp?Prod ... 1=7458&l2=

or

http://www.bluesea.com/product.asp?Prod ... 1=7458&l2=

I believe you have to have a combiner as well. This charges each set of batteries, but doesn't link them together.

Here is one:

http://www.marine-electronics-unlimited ... k+ACR.html

or

http://www.bluesea.com/product.asp?Product_id=22756

Right now I am on the traditonal OFF/1/BOTH/2 switch, but want to simplify the systems on the boat. Not sure if "adding" a combiner is simplifying, but it does automate it to a certain extent.

Question for the masses....

Asked only to simplify the systems on board and not to be cheap...

Do we really need a disconnect switch on the starter battery? If all it is doing is running the starter and powering the engine systems does any of that place a load on the battery once the engine is down?

Is there a reason I am missing?

It won't shut down a diesel, but you could kill an alternator.

It would shut down a run away starter....never had that happen in 30 years of playing with engines.

Maybe to isolate it off the grid when you add in the house bank if you killed the starter battery?

CharlieJ · Post by **CharlieJ** » Wed Apr 19, 2006 8:36 am

I HAVE had a runaway starter - on a diesel van. By the time I managed to get both batteries disconnected I also had a burning starter.

I think I'd ALWAYS have some way of killing the circuit pronto.

Ric in Richmond · Post by **Ric in Richmond** » Wed Apr 19, 2006 9:34 am

It is part of the ABYC requirements.

Getting the switch noted above takes care of it so that is what I am going to do.

Just seems like with a dedicated battery it might not be needed (except for the runaway situation) since millions of cars do without one every day.

jollyboat · Post by **jollyboat** » Wed Apr 19, 2006 10:32 am

There is a article in this months issue of SAIL magazine that covers at least part of your question. Page 68 (Outside the Box)

Figment · Post by **Figment** » Wed Apr 19, 2006 2:37 pm

The ability to disconnect the engine battery is handy because it disables any problems that might pop up associated with trickling voltage drain and even some underwater electrolysis issues.

For charging two (or more) batteries at once, a battery combiner is much better than the "both" position of a multipole switch. Even if the batteries are the same make, model and age, their different duties will require them to draw different amperages during charge cycles. It's a far healthier system.
A "smart" charging/monitoring system is better, of course, but that's a whole other pile of cash.

wstokes · Post by **wstokes** » Wed Apr 19, 2006 4:07 pm

Ric, I did some research last night and today I was able to talk to Blue Sea technical support. Essentially the new switch that they have isolates the batteries from each other but they do not allow charging both batteries at the same time. You need to purchase their automatic charging relay to go with the switch and then add the automatic charging relay switch panel. In terms of cost, the battery switch is approx. $40.00 CDN. The ACR relay is approx. $100.00. I don't have a price for the switch panel.

Blue Sea told me that if I wanted to charge each battery separately and have the option of charging both, then the basic battery switch #9001E will do the trick. ( I only charge one battery at a time anyway). My main concern is electronic device protection which they said, is protected in that their battery switch had a make and break function that prevented surges/spikes to the electronics when switching from battery 2 to 1 as an example.

So for me I am keeping to the basics and I have just purchased the 9001e battery switch.

Ric in Richmond · Post by **Ric in Richmond** » Wed Apr 19, 2006 10:04 pm

Good info.

That ACR can be had in one of the links I put in my first post for about 60.00.

I think that is the way I am going to go...with a fancy both on seperate circuits or both linked together battery switch.

Now I have a spare off/1/both/2 switch and I am thinking of separating my house banks (4 6 volt deep cycles in two banks). That way you could run an autohelm and other stuff all day and still have a house bank in reserve....