How do battery combiners work?

[strippingguards]

While reading my West Marine catalog - they sold me on the idea that I needed a battery combiner in addition to having 3 on/off switches instead of my one off-1-both-2 switch. I definately see the logic here - enough so to go out and purchase a combiner for $75. I will isolate my house and engine loads and I will assume that the combine "kicks in" while charging but keeps the batteries isolated while not charging. It sounds like there is a switch of some kind that knows when the batteries are being charged.<br />I currently have both batteries off the boat and I am testing the ability of this combiner in my basement but the combiner light does not come on immediately when charging. Eventually it clicks on and then sometiimes off. Is there something I'm missing here? Was I taken in by West Marine's Adviser - is this combiner really needed? For $75 I could have purchased a brand new starting battery.

 

[Yepblaze]

Re: How do battery combiners work?

"The battery combiner answer was straight forward. My concern was that when the combiner combined a fully-charged starter battery with a discharged house bank, there would be a high current flow from the starter battery to the house bank. Several people pointed out that this should not happen, as the combiner will only be triggered by a high charging voltage (from the alternator or battery charger), in which case the potential difference between the charging current and the house bank will be higher than the potential difference between the starter battery and the house bank, and hence, most of the current flow will come from the charging source. "<br /><br />From the web at http://www.bitwrangler.com/wt/lv-ab-bat-comb.html <br /><br />which was found by using google http://www.google.com/search?sourceid=navclient&querytime=FAwzF&q=How+do+battery+combiners+work?+

 

[strippingguards]

Re: How do battery combiners work?

is this combiner really needed?

 

[strippingguards]

Re: How do battery combiners work?

 

[petryshyn]

Re: How do battery combiners work?

How many batteries do you have?<br />How much current does your charger supply?<br />Is the charger automatic?<br /><br />*this will determine the need

 

[oldboat1]

Re: How do battery combiners work?

Doug -- sounds like another exercise in semantics (like outboard "alternator/stator" in your other post). If what you have is actually a battery isolator, the device permits automatic charging of two batteries while keeping the two electrically separated. This means that the lower charged battery will not leach power from the other battery, and that the charger will first charge the battery that has been most depleted. It is pretty complex to combine a battery switch (switches?) and an isolator (combiner?). You might be better off just periodically switching the house battery with the starting battery. At some point you might switch off the batteries while the engine is running, and your "alternator" system will be history.

 

[steve forsythe]

Re: How do battery combiners work?

I have 3 batteries in my boat with a switch that reads '1' '2' 'all' & 'off'. One of my batteries is a starting battery. Last weekend my 3amp fuse on my fish finder kept blowing. Could my problem be related to Doug's? Do i need an isolator or combiner? Before i go out i usually charge the batteries full or at least check them. When out,i sometimes switch the position to 1 or 2 or all to make sure they all get charged. Am i doing this all wrong?? Sorry to add a question to someone elses but i figured he might be able to use the info.

 

[petryshyn]

Re: How do battery combiners work?

Yo chumbucket<br /><br />