dual. battery set up

SteveTresa

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after almost 10 years i decided to install a dual battery set up in my 24sslx . the switch has battery 1, both, 2, off. when starting the boat do i keep the switch on both to charge both batteries and when we get to a cove turn the switch to battery 1 to use axillary power ? then when we leave switch to battery 2 to start the engine ? I wired the system to Benningtons drawing 4069 dual. I understand not to turn the switch while the engine is running, so the only way to charge battery 1 is to run in switch both. also i have a Yamaha 115hp engine will the alternator be able to charge both batteries at the same time ?
 

Jack M

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You are going to most likely receive a different answer from everyone who answers . I keep mine off when docked , switch it to both when underway and on alternating days out, switch between 1 and 2 at the sandbar for the stereo .I switch back to both for the ride back then off when docked .
 

SteveTresa

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Thanks Jack M, I wasnt sure how to charge battery 1 back up when starting the boat on battery 2. I was told not to change the switch when the engine was running , but keeping the switch to both sould work , thank you again for your reply
 

Jack M

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You're welcome.
You did bring up a point I forgot to mention ,as far as not changing the switch position while the motor is running.
 

Timdelta

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Any good battery switch will not disconnect a battery until the other is connected. The blade of the switch doesn’t disconnect until after the blades make a connection on the other battery.
For instance in bat 1 switching to 2 you go thru 1&2 prior to being only on 2. Same deal in reverse, so switching from one battery to another is not a factor, AS LONG AS YOU. DON’T GO THRU OFF.
Easy to checkout; with motor off just turn on something like lights or stereo and try batt 1 to batt 2 transfer.
I used to start motor on motor on one battery (odd batt on odd day, even batt on even day) then transfer to both while cruising. Then at anchor back to one battery using the non-starting batt for stereo, etc…. Problem was, I am so close to sandbars batt wouldn’t have time to charge, so I put a Solar charger on lift to keep batt 2 full and just start on 1 and then go to both while cruising and only use batt 2 for anchor time.
For the last two hurricanes I’ve left batt switch on both and left bilge pump on auto. The Solar kept both batteries full, so that worked great.
 

Vikingstaff

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We use our dual set up precisely as Jack above described.
 

BigKahuna

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We alternate batteries every time out. But on the way home we'll put it on both to charge everything!
 

SteveTresa

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Any good battery switch will not disconnect a battery until the other is connected. The blade of the switch doesn’t disconnect until after the blades make a connection on the other battery.
For instance in bat 1 switching to 2 you go thru 1&2 prior to being only on 2. Same deal in reverse, so switching from one battery to another is not a factor, AS LONG AS YOU. DON’T GO THRU OFF.
Easy to checkout; with motor off just turn on something like lights or stereo and try batt 1 to batt 2 transfer.
I used to start motor on motor on one battery (odd batt on odd day, even batt on even day) then transfer to both while cruising. Then at anchor back to one battery using the non-starting batt for stereo, etc…. Problem was, I am so close to sandbars batt wouldn’t have time to charge, so I put a Solar charger on lift to keep batt 2 full and just start on 1 and then go to both while cruising and only use batt 2 for anchor time.
For the last two hurricanes I’ve left batt switch on both and left bilge pump on auto. The Solar kept both batteries full, so that worked great.
Hey Thanks Timdelta that was a great answer to a question i forgot to ask , so thats the reason i installed a second battery I wasn't going far enough out to charge a battery for the time period we would use our axillary switch , lights, radio etc. so now i know i can turn the switch from 1,both,2 without interruption makes sence. there was a warning never to switch to off while the engine is running, ha ha i assumed not to turn the switch at all after the engine was running thinking it disconnected between 1,both,2. thanks again Timdelta i appreciate you thaking the time to answer my concern.
 

Potomacbassin’

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Regardless of number of batteries (1,2 or 100) if you are using more voltage to crank your engine and sandbar activities than you are replacing via the alternator you'll need an external charging source at some point. Shore power plug, solar, bringing battery home etc.

Couldn't tell you how much running charge time you need to offset your particular usage as it depends on several variables, so if you're unsure what your charge state is make sure you carry a portable lithium jump pack. I have a Garmin MFD that will give me a voltage reading and you may have the same.

In regards to the automatic charging relay/isolator mentioned above I highly recommend. No more messing around with which battery to switch to and which to charge, everything is done automatically using sensing electronics. On or Off, that's it - both batteries do what they're assigned to do and automatically charged based on priority to your cranking battery.
 

SteveTresa

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I've got an other question during the off season can I trickle charge the batteries one at a time in the boat if the battery switch is in the off postion without removeing the battery from the boat ? I normally remove tne battery during trickle charge.
 

scottkp

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I am old school and take my batteries out in the winter - it is what my grandfather, my dad and I have done, hard to teach an old dog new tricks I suppose..... Batteries/power management seems to be a hot debate, so I guess do what feels right for your situation.
 

LaurencetheAdventurer

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Regarding switching the Battery from #1 to Both to #2 while running. I have read a LOT of different opinions on this, so spent a little time reviewing various posts and ultimately looked at the Perko Site. I conclude: The new Perko switches have a "make before break" feature now "allows switching between the 1 - all - 2 positions while the engine is running (which I assume means the 2nd battery is connected before the 1st one is disconnected and then combined). Various posts suggested that the older switches did not have this feature, and everyone agrees that turning the battery OFF while running is BAD. I could not find a single post where someone had an issue doing this switch while underway with a new switch. I noted over this last summer I could switch between the batteries while floating - without interrupting the stereo from playing (1 to Both to 2). I also noted that Perko has a switch an Alternator Field Disconnect, offering protection for non-unitized alternators if the switch was accidently turned off while running - no idea what that is, but they have it.
https://www.perko.com/faq/ (last choice - Switch Technical Information).
OF course the safe course is probably to NOT switch between batteries while running, any time you add in more variables - more possible failures, but it seems this is not necessarily terrible as in the "ancient days"......LOL.
 

SteveTresa

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First off thank both you Scottkp and Laurence for your replies. Yes i'm old school also, i do remove the batteries when at home charging them. I worry about off gases damagining the interior. I do have a Perko switch and proably won't be switching batteries around while underway. Thank you for Perkos web site FAQ I'll be looking at it later today. Take care guys
 

DanOnTheRiver

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I've got an other question during the off season can I trickle charge the batteries one at a time in the boat if the battery switch is in the off postion without removeing the battery from the boat ? I normally remove tne battery during trickle charge.
Use a battery "conditioner" for best results. Trickle will not turn off as the batter cooks. Conditioner will monitor the battery and turn on when needed.
 

chris288

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ive had a perco battery switch in my boat since 2004, it has off, 1, 2, both, and you most certainly can switch between 1, 2, or both while underway. i run on 1 or 2 to keep them charged never both as on my I/O it wasnt good for the alternator. if beached, leave it on 1, if everything dies switch it to 2 for starting then back to 1 to charge it back up. larger outboards have charging systems that can handle running on both and not harm them.
 

JP10

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In my 13 years of owning and running my fiberglass Bennington, I've gradually resolved to not overthinking things. Batteries being one of them. I run a pair of group 27's, the Autozone marine variant. Change them out every 5 years. Carry a never used charge pack on board. Leave it on both batteries all the time, except on the lift. Run a JL Audio 700 series amp, 4-8" speakers, 2-10" subs, and a Garmin. I turn off the garmin when anchored. Never had a problem starting or running.
 
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