Dual Battery System Management Recommendations?

[Rbertalotto]

This looks good, but the wiring diagram shows four units, unless I'm reading this wrong

http://www.bepmarine.com/media/product/pro4c27c7b7be28f.pdf

 

[ntsqd]

This is about as good and easy as it gets.

http://www.bepmarine.com/home-mainmenu-8/product-269/125-amp-voltage-sensitive-relay-vsr-

About $70, no voltage drop and idiot proof.

I agree, been a proponent of them since first discovering them. Though not this exact thing (wasn't available when I purchased or I would have bought it) what I had staged for the Sub, but has now been moved to the FJ60 project is effectively this:
http://www.bepmarine.com/home-mainmenu-8/product-273/714-100a-single-engine-two-battery-banks
Adding the battery switch adds self jump-start capability as well as a way to charge the second battery should the VSR fail (simple redundancy is a good thing!).
About the only thing that I'd ask for if they were to change the VSR would be to add a timer delay between threshold first battery voltage and solenoid engagement. Give the first bank a little time to make sure that it is fully topped off before starting on charging the second bank.

 

[theksmith]

This is about as good and easy as it gets.

http://www.bepmarine.com/home-mainmenu-8/product-269/125-amp-voltage-sensitive-relay-vsr-

About $70, no voltage drop and idiot proof.

it's a excellent simple unit, i was looking more at their 710-300A (just a higher amp rating and a manual switch on the unit). as far as i read, it's almost exactly the same as the Blue Sea ACR unit that i chose. the main difference being that the BEPMarine VSR uses a momentary switch to link batteries for 10 minutes and the Blue Sea uses a rocker switch to link batteries how ever long you wish. The downside to the Blue Sea is that you could forget you linked the batteries and kill both of them... the 10 minutes of the BEPMarine however isn't enough for when you might want to link batteries for a winch-fest - I think either unit is excellent and overkill even, as you said, the 710-125A should meet most people's needs for a good price.

 

[alexrex20]

Overkill? What's that mean?

 

[theksmith]

This looks good, but the wiring diagram shows four units, unless I'm reading this wrong

http://www.bepmarine.com/media/product/pro4c27c7b7be28f.pdf

there is only one VSR, and only one is required. there are 3 manual switches in this diagram, the 2 on the outside allow you to completely isolate a battery for service or just to forcefully take one out of the automated charge/draw. the one in the middle allows you to self-jump manually (which you shouldn't really need either since you have that ability with the remote momentary switch of the VSR).

the competing Blue Sea product shows the same sort of diagram, except they try to sell you their remote-control switches instead of manual switches: http://bluesea.com/files/resources/instructions/990180180.pdf

i think they are both just showing you a system with the utmost manual control and safety built in and trying to sell more products too!

 

[snowbear]

regulator sense wire

Currently I have dual batteries in parallel, no switches or controls apart from stock wiring. 89 Toyota PU.

Maybe I'm just slow but I've read thru all these dual battery discussions and still can't figure out what folks do about the internal voltage regulator sense wire. As I understand it this wire is connected to the the battery via the ignition switch and controls the output voltage of the regulator. Without it the regulator would run full power all the time.

Say I put the single rectifier power gate in my rig. It connects in series between the alt output and the main battery. The main battery is feeding the sense wire and when that battery is charged the alternator output voltage is reduced leaving the aux battery undercharged.

So I say, use the power gate dual rectifier model. It has a connection to the "house" wiring. What power gate shows as "switched 12VDC". However this switched 12vdc is still fed from the main battery. And so the same problem still exists. When the sense wire sees that the battery connected to the house wiring is fully charged the alternator reduces its output, leaving other batteries undercharged.

It seems like the sense wire needs to be directly connected to the control system. The control system needs to supply it with voltage from the lowest battery in the system, then route power from the alternator to that battery. Anything else would leave some batteries undercharged or possibly overcharging others.

I've looked at hell roaring and national luna and don't see where the sense wire is addressed there either. Am I missing something or making this too complicated? Maybe I misunderstand how the sense wire works?

 

[spressomon]

FWIW: My Powergate (dual rectifier) has been working perfectly since the day it was installed. Keeps my two Odysseys fully charged without issue. Super easy to bridge the batteries should I need to...

Now if they would just get their new Mobiarc to me so I can check that off my list.... Scott are you reading this?! :coffeedrink:

 

[Perfect Switch]

(Hanging head in shame) Updated PCB's currently being fabricated....should be delivered to the contract assembly house later this week, then it will take them around a week to populate the boards....so we're getting close.

FWIW: My Powergate (dual rectifier) has been working perfectly since the day it was installed. Keeps my two Odysseys fully charged without issue. Super easy to bridge the batteries should I need to...

Now if they would just get their new Mobiarc to me so I can check that off my list.... Scott are you reading this?! :coffeedrink:

 

[alexrex20]

i'm selling my brand new Painless 40103 setup.

http://www.expeditionportal.com/forum/showthread.php?t=55373

 

[dwh]

Just read this whole thread and the *simplest* is a standard split-charge relay setup:

You can buy whatever size solenoid you need for it and wire it so that it gets power when the key in the run position (but not acc position if you want to run the radio from the acc with the engine off).

My old 76 Ford camper van has this setup. All chassis loads to the engine battery (factory original setup) and all camper "aux" loads to the aux battery. I can beat the aux battery up or run it dead or whatever and the engine battery is isolated. As soon as the truck starts both get charged.

If I run the engine battery down, as soon as I turn the key on the batteries are tied together and the truck can get jumped from the aux battery.

When I first got the truck, it wouldn't jump itself with standard battery cables. I swapped them out for thick battery cables and now it will.

Doesn't get any simpler than that.



EDIT: P.S. I stole the diagram from PowerStream and the little box added to the solenoid in the diagram is their little add-on computer controller that waits until the engine battery is charged up to 13.6v before it ties in the aux:

http://www.powerstream.com/battery-isolator.htm

 

[dzzz]

The bep and blue sea are solenoids in a package with other features. I feel the added cost over a bare solenoid is usually worth it.
My blue sea has a cabin switch that has connect-auto-disconnect. In auto it watches voltages as well as drops out the house batteries on engine crank. It's $100 more than a bare solenoid. But there's a lot of functionality for $100. (it's also water proof and has a local switch).
The marine products are used exactly as their automotive competitors. But are typically more refined designs and sealed.

 

[dwh]

I feel the added cost over a bare solenoid is usually worth it.

No doubt. There are some very nice setups available. My point was that all the posts that said "simplest" were *not* the simplest. So I posted the simplest.

Simple.

 

[dzzz]

Didn't Overland Journal do a write up a couple years ago? I don't think it included marine vendors, but it did have the main automotive vendors people talk about here.

I noticed the Hellroaring device has heatsinks. That's oldschool in a bad way. Well not "bad", but technologically obsolete.

I don't see that powergate has an advantage over voltage sensing relays. It is more expensive. What am I missing?

 

[Xterabl]

I don't see that powergate has an advantage over voltage sensing relays. It is more expensive. What am I missing?

Robust, reliable, and simple. It's a set and forget solution. If you don't want to flip switches, or worry about a relay or other mechanical parts breaking down, there is no other option that offers nearly the same performance.
The tradeoff is you may lose a bit of flexibility. For me, it has been well worth it. Oh, and the customer service was fantastic, too.

 

[dzzz]

there is no other option that offers nearly the same performance.

You offer no support for your claims.
Also the more technological solutions discussed in this thread can run fully automatic, as a brief read of documentation reveals. Some of the marine solutions can do this underwater. The marine units have to obtain high standards of construction and reliability as their functioning in an emergency is potentially "life and death".

Vague claims of superiority and highest cost are not features. I would genuinely like to know what, if anything, powergate does better.