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Discussion Starter · #1 ·
I've got two batteries, one for starting, one for the tunes. Question: If I hook them both up on a perko switch, can I start the motor on the starter battery, then safely switch to the other for charging?
 

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I have too, but you are not supposed to. If there is a load on the electrical system, it can create an arc between the contacts while switching. When the engine is running, there is a charging load there. I dunno......
 

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The thing that goes are the alternators didodes and thats if you pass an off position in the switch. say if the off position is between batt 1 and 2.

I know there are some that go off,batt1,both,batt2.in this case your batts never get disconnected from the alternator.

I use to do this with mine and never had a problem.But have since installed an isolator and have a dedicated stereo battery so when i am running both batts are getting charged but starting battery is never drained with no turning of the perko switch.Also have it wired that i can use batt 2 to jump batt 1 if needed by turning it to both.
 

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Discussion Starter · #8 ·
I thought that running "both" was a bad idea because if one of the batteries starts going bad it will put additional stress on the good battery...
 

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Discussion Starter · #10 ·
Can you go into a little more detail on the Isolator? Whats its purpose?(let me guess, to isolate?) Is this run in addition to a switch?

Im trying to run 2 batteries reliably and not have to go for a cruise every half hour to get the stereo battery charged again and still have enough juice to crank the motor when its time to pack up. I have 2 optima Reds and a blue to choose from...
 

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Can you go into a little more detail on the Isolator? Whats its purpose?(let me guess, to isolate?) Is this run in addition to a switch?

Im trying to run 2 batteries reliably and not have to go for a cruise every half hour to get the stereo battery charged again and still have enough juice to crank the motor when its time to pack up. I have 2 optima Reds and a blue to choose from...
#1 most battery switches (all marine grade) have a "make before break feature" so switching the switch while running should not cause any issues.
#2 an isolator is the only way to go, it will provide the ability to run your battery switch in #1 or #2 while charging both batteries equally, wired properly you should never have a dead battery.

The way is works is it separates the alternator charge circuit in two, much like a cable TV splitter.

Very easy to install and virtually maintenance free.

GT :)hand
 

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Can you go into a little more detail on the Isolator? Whats its purpose?(let me guess, to isolate?) Is this run in addition to a switch?

Im trying to run 2 batteries reliably and not have to go for a cruise every half hour to get the stereo battery charged again and still have enough juice to crank the motor when its time to pack up. I have 2 optima Reds and a blue to choose from...
It will basically sense what battery is in more need of a charge and direct more current to it.Will not overcharge and get both batts a full charge.

pretty easy to wire up instead of having the charge wire from the alt go to the perko or wherever you have it go to the isolator.Then from there you add a wire from the isolator to each battery.

It will eliminate the hassle of switching batteries every stop.I would separate the stereo batteries too and have hem for stereo only after you do the isolator.
 

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I am Roger..the Shrubber
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On my old boat I ran a ACR (automatic charging relay) from Blue Sea. Better than an isolator IMO. It prioritized the recharge from the alternator. Once it sensed the starting battery was full it automatically switched over to the other battery.


Basically...here's what I did. I still had the bual-batt switch. Just ran in dual at all times. Then I isolated the draw to their designated areas. Fairly simple yet effective for the $60-70 for the ACR.


Here's mine in a tight little area.

 

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Wow, that's really cool, and complex.

I leave my Perko switch set to "1" or "2" all the time. When the boat goes in the garage I hook up the installed charger. If I run the stereo all day, like I did during the movie shoot, I only drain one battery. The boat won't start, so I switch to the other battery, fire it up, and then switch to "both". After the voltage stabilizes, based upon the gauge on the dash, I switch it to the battery that was "dead" to charge it back up.

I learned early on to never leave both batteries connected in parallel all the time, even if they have the same lot number and same manufacturing date/time stamp. If one has a tiny bit more juice than the other, it will try to fill the lower one, and will end up dead. They will work back and forth, charging each other, and discharging themselves. The end result is two dead batteries. I had to ruin many pairs of batteries to learn this, I can be a slow learner.
 

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MEDIUM PIMPIN!!!
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Wow, that's really cool, and complex.

I leave my Perko switch set to "1" or "2" all the time. When the boat goes in the garage I hook up the installed charger. If I run the stereo all day, like I did during the movie shoot, I only drain one battery. The boat won't start, so I switch to the other battery, fire it up, and then switch to "both". After the voltage stabilizes, based upon the gauge on the dash, I switch it to the battery that was "dead" to charge it back up.

I learned early on to never leave both batteries connected in parallel all the time, even if they have the same lot number and same manufacturing date/time stamp. If one has a tiny bit more juice than the other, it will try to fill the lower one, and will end up dead. They will work back and forth, charging each other, and discharging themselves. The end result is two dead batteries. I had to ruin many pairs of batteries to learn this, I can be a slow learner.
I've been running the big optimas parallel for 4 years now with no problems??
 

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#1 most battery switches (all marine grade) have a "make before break feature" so switching the switch while running should not cause any issues.
#2 an isolator is the only way to go, it will provide the ability to run your battery switch in #1 or #2 while charging both batteries equally, wired properly you should never have a dead battery.

The way is works is it separates the alternator charge circuit in two, much like a cable TV splitter.

Very easy to install and virtually maintenance free.

GT :)hand
This is the way I understand it.

In addition, (my 2 cents) the way it was explained to me to purchase a battery isolator, if you have 100 amp alternator you will need a 110 amp or higher isolator. Example, I have 1 wire GM 140 amp alt. with a 160 amp isolator. This seems to work real good, I haven't had any battery problems in the 3 years since i wired it up. :)hand
 

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On my old boat I ran a ACR (automatic charging relay) from Blue Sea. Better than an isolator IMO. It prioritized the recharge from the alternator. Once it sensed the starting battery was full it automatically switched over to the other battery.


Basically...here's what I did. I still had the bual-batt switch. Just ran in dual at all times. Then I isolated the draw to their designated areas. Fairly simple yet effective for the $60-70 for the ACR.


Here's mine in a tight little area.


Where to buy and part number?
 
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