another dual batt question

[rob711]

i posted this in another section but it clearly belongs here...i am considering adding another battery to my boat..i under stand how the 1-2-all swithes work...there is a system by a company called add a battery with a switch that is either on-off or both....my question is does it know which battery is where...i'd like to be able to float around with accesories on without killing my starting battery....i figure worse case i kill my house battery, but when its time to go the engine starts on the starting batt and off we go...why would i want to combine both batteries..
rob

 

[Silvertip]

Re: another dual batt question

I'll answer your last question first. You want to combine the batteries to charge them both while under way. If you couldn't combine them (parallel them) the house battery would never get charged. You want them isolated when doing whatever you do when the engine is not running. I know nothing about the company you mention or their product. With a separate battery switch however (OFF-1-BOTH-2), Battery #1 is whatever battery you connect to the #1 terminal on the switch. If that's the START battery, BAT 1 is the START battery and BAT 2 is the HOUSE battery. Remember that all of the loads are not wired to the batteries -- they are wired to the COM terminal on the switch with one exception. You want the bilge pump wired directly to one or the other batteries. The battery switch therefore gives you total flexibility. You can run accessories from either or both batteries. You can start from either or both batteries and you can charge either or both batteries.

 

[PondTunes]

Re: another dual batt question

Silvertip he is asking about the Blue Sea Systems add-a-battery setup, which is an automatic setup and requires no switching.

I answered your question in the other post as I saw it there first.
http://forums.iboats.com/showthread.php?t=227772

I'm actually thinking about putting one of these in my truck next with a spare battery for inverter power / remote installs where there is no power.

 

[rob711]

Re: another dual batt question

ahaa...thanks pond..i think this is the system i'm going to go with..u cleared it up, i looked on their site but it did not explain it really..its a bit expensive compared to a 1-2-all switch, but its also eaiser...for my purpose i'll leave it on and not have to worry about if i've been sitting to long on one batt. thanks...hey any ideas on where i can get some cables made up...again i think this has been covered before so i apoligize....i'm not going even to mention which is better...crimped or soldered

 

[wire2]

Re: another dual batt question

..its a bit expensive compared to a 1-2-all switch, ...

Unless I missed something, this auto switch can be very cheaply mimicked with a single 12 volt relay. The + from each battery is connected to the contacts, the coil connected to gnd and Ign.

With key on, both are connected together and to alternator.
With key off, start and house are isolated.

 

[rob711]

Re: another dual batt question

sure its simple....this comming from a person called wire2...something tells me your a lot more savy when it comes to electrical issues then myself...thanks for the idea though.