Dual Battery Advice (1 Viewer)

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I still cannot understand doing anything but a constant rate solenoid..

I ran one for years. If they fail, it takes about 5 mins to either swap it out or just connect the two terminals.

And$30 for the entire thing.

BTW, I would do welding cable for battery leads.. Actually, I do use welding cable for almost everything.
 
Some definitions just in case there's any confusion:

A constant duty solenoid is intended to be turned on for long periods of time and will not carry starting level current. It need only have a current rating for the max charge rate of the alternator, if that. It is rare that an alternator puts out it's maximum current as few batteries can accept that rate of charge for very long without damage. It does not need to handle starting currents unless you want to be able to self jump-start. In which case you're using the wrong solenoid for the job. Cole-Hersey is the mfg of most of these that are used in the U.S.

The Ford type solenoid is an intermittent duty solenoid and not a constant duty solenoid. It is intended to be turned on for short periods to start an engine - not stay connected for hours at a time. Because of the high current application they use a strong spring to break the connection (the contacts can 'weld' themselves together). To over-come that strong spring a strong electro-magnet is used, and those use a lot of power and generate a lot of heat. Keeping one of these solenoids energized for a long period of time is a recipe for a melt-down.

------------------------------------------------------

That there is no one 'correct' way to build a multi-battery system is evidenced by all of the options available. With this bewildering array of options the best that each of us can do is present why we chose what we used.

The ACR/VSR option is only for automatic charging the aux. battery. Any other needs must be met with some other device. I prefer this option because it is "smarter" than just a constant duty solenoid. If you wire it correctly a constant duty solenoid is on only when the ignition is on, not when cranking or when the accessory is on. What I prefer about the ACR/VSR option is that it works essentially the same way, with one additional feature. The unit monitors the starting battery and allows the charging system to bring the starting battery back up to full charge before connecting the aux battery for charge. The constant duty solenoid simply connects them together when ever the key in the 'run' position (assuming wired correctly) regardless of the state of charge of the starting battery.

The reason that I prefer the marine battery bank combiner switch over any other option is that I have to deliberately switch it. I won't accidentally bump a toggle switch and discover that fact 3 hours later. Yeah, I could put indicator lights and a guard on the switch. I prefer that things be simple and uncluttered. In a land vehicle switching batteries means opening the hood. So I know when it has been switched and when it has not. My normal mode of operation is for the combiner switch to set on start battery only. That way the only connection of the aux. battery to the vehicle's main (OE) systems is through the ACR/VSR. Should the ACR/VSR fail, this combo of two separate units gives me redundancy and I can still charge the aux battery.

What I did not like about the HR unit was that it is one integrated unit. Should I need to wire around one of it's functions I don't think that it's possible. Other folks may like that it is one integrated unit. Isn't the free world great? We get to choose what we want.

A friend runs a constant duty solenoid in parallel with a Ford starter solenoid powered by the aux. battery. Simple and easy. The constant duty does the charging and the Ford deals with winching and jump-starts.

Something that hasn't yet been mentioned here is some sort of battery monitoring. I'm thinking to use a simple voltmeter with a SPDT double momentary switch to select the battery to test the voltage of.
 
Last edited:
ntsqd said:
What I did not like about the HR unit was that it is one integrated unit. Should I need to wire around one of it's functions I don't think that it's possible. Other folks may like that it is one integrated unit. Isn't the free world great? We get to choose what we want.
Click to expand...

Not sure what you mean but I can run a jumper if needed to combine or to self-jump in my particular case running main/aux/backup.
 
ntsqd said:
Something that hasn't yet been mentioned here is some sort of battery monitoring. I'm thinking to use a simple voltmeter with a SPDT double momentary switch to select the battery to test the voltage of.
Click to expand...

I have been contemplating the Xantrex battery monitors
 
NLXTACY said:
Not sure what you mean but I can run a jumper if needed to combine or to self-jump in my particular case running main/aux/backup.
Click to expand...
My exposure to an HR is limited to what I can see on the net and a one-time exposure to one on an acquaintance's Early Bronco, so I can't claim any familiarity. From what I could tell it looked like to by-pass any given feature required tools?

Just the name Xantrex strikes terror in my wallet. :D
 
ntsqd said:
My exposure to an HR is limited to what I can see on the net and a one-time exposure to one on an acquaintance's Early Bronco, so I can't claim any familiarity. From what I could tell it looked like to by-pass any given feature required tools?

Just the name Xantrex strikes terror in my wallet. :D
Click to expand...

Yeah I keep a jumper wire "just in case" but like I said, I have never heard of one going bad.

And yeah Xantrex hurts bad but after seeing this bad boy in use:
Xantrex Link 20 Battery Bank Monitor #84-2020-00 --Ultimate Passage Discount Marine Electronics

I fell in love. Not sure I'd rock $300 of battery monitory in my 60.
































But I sure would in my LX! :flipoff2:
 
National Luna has a battery monitor as well. Maybe it's cheaper, I didn't see a price on their website.
National Luna
 
slcfj62 said:
A simple voltmeter is all you need IMO.
Click to expand...

But how would you know how much juice you have left? Or is the battery is getting low?

My interest in knowing each "bank" level is so I can turn-off accessories or trim usage so I dont deplete both batteries.
 
My first time delving into the dual battery discussion, so bear with my inexperience...

I was thinking of using this:

Xantrex PathMaker100-2B - Xantrex PathMaker 100 - 100A with 2 Battery Banks

With the control/diagnostic panel mounted in the cab (tuffy, glove comp. etc.) or attaching a push button remote for self-jump start in the cab.

Setup would be similar to this bajataco writeup, using an Exide Orbital as starting and Die Hard Marine as Aux. Tacoma Dual Battery System

Battery monitor would be:

Battery Gauge

Trying to see what the negatives of a system like this would be.

Cheers,

Kevin
 
OUTSIDELC said:
My first time delving into the dual battery discussion, so bear with my inexperience...

I was thinking of using this:

Xantrex PathMaker100-2B - Xantrex PathMaker 100 - 100A with 2 Battery Banks

With the control/diagnostic panel mounted in the cab (tuffy, glove comp. etc.) or attaching a push button remote for self-jump start in the cab.

Setup would be similar to this bajataco writeup, using an Exide Orbital as starting and Die Hard Marine as Aux. Tacoma Dual Battery System

Battery monitor would be:

Battery Gauge

Trying to see what the negatives of a system like this would be.

Cheers,

Kevin
Click to expand...


IMO - the Xantrex product you named above is very expensive for what its actually doing.

That battery monitor is awesome... havnt seen one that good for the price.
 
As I'm not that electrically intelligent, what could replace the Xantrex? A simple solenoid and switch?

Thanks for the help.

kevin
 
dtrain said:
But how would you know how much juice you have left? Or is the battery is getting low?

My interest in knowing each "bank" level is so I can turn-off accessories or trim usage so I dont deplete both batteries.
Click to expand...

You can tell the approximate charge level by these voltages with this caveat: These are only exactly valid for 80o F and if the battery has been sitting idle for several hours. So, if the battery is at a different temperature, and you want to be precise, use this fudge factor.
  • Add .004 to readings for every 10o above 80o F
  • Subtract .004 for every 10o below 80o F.
So, here are no load voltages at 80o F and corresponding charge level:

100%..........12.73 Volts
90%............12.62 Volts
80%............12.50 Volts
70%............12.37 Volts
60%............12.24 Volts
50%............12.10 Volts

You should never discharge below 50% for a deep cycle battery. A starting battery should never be discharged below 80%. So just remember 12.50 Volts is 80%, and 12.10 Volts is 50%. Follow this rule, and your batteries will last 10 years or longer.
 
Last edited:
dtrain said:
My interest in knowing each "bank" level is so I can turn-off accessories or trim usage so I dont deplete both batteries.
Click to expand...

I would not use the vehicle starting battery for anything but starting the vehicle. Keep it in reserve.

Two 6V AGM deep cycle batteries in series would be my choice for "house" batteries. And if you really want to go first class, an 80 watt solar panel and a charge controller would allow you to "rough it" in the bush and run your fridge, radio, etc indefinitely.
 
slcfj62 said:
You can tell the approximate charge level by these voltages with this caveat: These are only exactly valid for 80o F and if the battery has been sitting idle for several hours. So, if the battery is at a different temperature, and you want to be precise, use this fudge factor.
  • Add .004 to readings for every 10o above 80o F
  • Subtract .004 for every 10o below 80o F.
So, here are no load voltages at 80o F and corresponding charge level:

100%..........12.73 Volts
90%............12.62 Volts
80%............12.50 Volts
70%............12.37 Volts
60%............12.24 Volts
50%............12.10 Volts

You should never discharge below 50% for a deep cycle battery. A starting battery should never be discharged below 80%. So just remember 12.50 Volts is 80%, and 12.10 Volts is 50%. Follow this rule, and your batteries will last 10 years or longer.
Click to expand...

Great info (may have to add this to the glove box journal in my trucks).

What if the batteries have not been sitting idle for several hours? How does that throw off the calulation?

What is your take on these live meters? Do you think they take into account the elememts you described above and/or are fairly accurate?


slcfj62 said:
I would not use the vehicle starting battery for anything but starting the vehicle. Keep it in reserve.
Click to expand...

Agree'd... I just have a slight variation on that.

My starting battery will only have the vitals connected (starter, alt, x2 electric fans - 1 always on & 2 temp sensing, main fuse panel for lights, wipers, etc)

Second battery will have rock lights, stereo, cig ligheters, winch, etc. connected.
 
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