Dual Battery System

flysurfer

Registered Member
City
Salt Lake City
I want to add a second battery 'house battery' to my 170 and was wondering if anyone has had any experience with the Blue Sea 7650 Solenoid/Battery Dual Circuit System. I plan to use a marine/starting battery for the motor and a deep cycle battery for my electronics. Any suggestions would be appreciated.
 
I have two deep cycle batteries under my console for use with my 24 volt trolling motor...I use one of them for all of my electronics. They are both charged by an onboard charger that I plug in when the boat is in the garage. My starting battery is seperate and is charged by the engine. I haven't had any experience with the system you described.
 
Thanks Cargrove. I'm converting a 170 Sportsman into a 170 Cool and I'm using the helm console from a 170 Side Console for the center console and have room for one battery, which is all I need. I've thought about doing it your way but you know how we boaters are, sometimes we go overboard (no pun intended) with gadgets and we forget about 'simplicity'.
 
Hey, I'm all about gadgets...I love me some gadgets! :D Use whatever works for you...that's what makes a your boat unique...it fits your personal style.

Good luck with your mod...oh, and take some pictures to share with us along the way. We love sharing ideas and learning new things.

Tight lines.
 
Flysurfer,

I use the BEP cluster which totally isolates the Start battery from the House battery but gives you the ability to connect them together if you need it. The volt sensing relay gives charging priority to your Start battery first, then the house battery. You will never have to rember to switch between 1 or 2 and your electronics and other loads will not be connected to the engine load. Below is a wiring diagram of my battery setup. Works very well. True isolation and very simple.:cool:
(note: Disregard the #8 negatives to ground. those are for my downriggers.)
 

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I agree with Push&Pull, only we built our own.

See picture below. Hope this helps.

full
 
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Thanks for the responses. Your replies did give me some ideas and are appreciated.

I did a bit more research and I think I'll go with the Blue Sea Solenoid/Battery Dual Circuit System. It's seems to be a simple system. The switch with the unit has an 'off, on, combine' that is simpler that most dual switches with the '1,2,both, off' switches.

The kit also includes an SI* Automatic Charging Relay that, as the Blue Sea site states "automatically combines batteries during charging, isolates batteries when discharging and when starting engines. It also allows temporary isolation of house loads from engine circuit during engine cranking to protect sensitive electronics". What I was looking for was a system that would isolate the starting battery from the house battery that will power my electronics, bait well and bilge pumps but will charge both batteries when underway. Seems like what I need but anymore input is welcome and again, thanks for your information and ideas.
 
flysurfer,
While both systems will work fine, here are some additional tid-bits about the systems..
If you use the Blue seas, it uses a combiner for charging, therefore you should use the same type and size batteries for both. Bep charges the start, then the House separately, so type and size does not matter. The separate switch systems also allow for turning off or on each battery separately. (I leave my House on to keep stored info alive. The Start off to keep anyone from messin with my motor&trim.) Another note......don't expect much charging from your "engine" with either system. It takes a long time to effect any real charge from the engine, if at all. Even with the larger engines & especially if you combine batteries.
 
Push&Pull,
Thanks for the heads up. I'm aware the charge from the motor is considered a 'trickle charge' but was not aware of the battery size issue which for me will be a consideration. Hmmm. More time standing back, scratching my head and deciding which way to go seems to be on the horizon. :)
 
Push&Pull,
Thanks for the heads up. I'm aware the charge from the motor is considered a 'trickle charge' but was not aware of the battery size issue which for me will be a consideration. Hmmm. More time standing back, scratching my head and deciding which way to go seems to be on the horizon. :)

With the blue sea system, the battery technology needs to be the same, but not necessarily the type. In other words, as long as the combined batteries are all the same tech (either all traditional flooded, all gel, or all AGM), the ACR will work just fine. You can have any combination of Starting, Dual-purpose, and deep cycle batteries since the relay is simply a voltage-sensing relay and uses your existing motor output as the current source.

Just a bit of advice,if you decide to use the blue sea system, purchase the ACR and switch separately if you buy from West Marine. They are cheaper that way than in the combo pack.


Also, the motor charge is most definitely not a "trickle charge". Motor charging output are generally anywhere from 20 to 60 amps on an outboard engine. Trickle charges are 2 amps or less. the reason engines typically don't charge more than around 80% is they are designed to bulk charge (fast charging using high current and high voltage) which on lead acid batteries only will work efficiently until the battery is 80% capacity, to finish the charge it is better to use a charging system with an float phase that holds a constant lower voltage (typically around 13.9vdc) and adjusts the current accordingly.
 
Thanks Frank and the other string members,

I am installing the Blue Sea isolation switch myself but ran into some issues. The battery I was given with my "new" boat, is not rated to the CCA or MCA the engine needs. Been fine so far (one summer) but now if I buy a new battery I wanted to go for a nice AGM. Looks like I can't mix the two techs though... hmmm, now what. Might just go with one nice AGM and keep the other at the house as a spare....
 
Thanks Frank and the other string members,

I am installing the Blue Sea isolation switch myself but ran into some issues. The battery I was given with my "new" boat, is not rated to the CCA or MCA the engine needs. Been fine so far (one summer) but now if I buy a new battery I wanted to go for a nice AGM. Looks like I can't mix the two techs though... hmmm, now what. Might just go with one nice AGM and keep the other at the house as a spare....

Well, as long as the two batteries are not connected, there is no reason you can't have both techs on board powering different systems.

Personally, I am leary of using an outboard motor with AGM's, simply because most outboard voltage regulators don't have a tight enough tolerance to protect the sensitive batteries. Further, for the amount of money, since I can readily get to the battery for maintenance, there really isn't a huge advantage to using and AGM other than the spill factor (and since the battery stays in the boat except during winter, not really an issue there either).

The average life expectancy for Lead-Acid batteries is still greatest with a traditional flooded cell, as long as it is properly maintained.
 
pamarine, I misspoke when I referred to the motor as a trickle charger, from what I've heard and my experience, an alternator does not charge a battery as fast as most people think they do. In addition, what is your opinion on gell batteries.
 
pamarine, I misspoke when I referred to the motor as a trickle charger, from what I've heard and my experience, an alternator does not charge a battery as fast as most people think they do. In addition, what is your opinion on gell batteries.

It's a bit of misperception based on observation. They charge right quickly to that 80% mark. But take a while to get the last 20%.

As for gel cells, waste of money. It's a bridge tech. either go traditional or AGM.
 
I just purchased 716-SQ-100AVSR Dual Battery Charging Cluster - BEP Marine. I have not installed the unit, as it just came yesterday. It looks pretty cool and should work fine as it is pretty much automatic switching and charging. $149.59.
 
The Blue Seas Dual control has worked great for me and has held up to the elements. I did find that standard batteries did not hold up well and moved to heavy duty marine batteries and built a support cradle to keep them level in the transome.

I also added the MinnKota battery stabilizer and have gotten what I feel is much longer life from the batteries. (8 years out of 3 deep cycles used for trolling) (4+ starting batteries).... maybe the stuff works.

I have the installation pics posted. I simply use a automatic deep cycle Fast charger for all my batteries (one at a time x 5) and none ever need more than 30 minutes to fully charge.
 
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