New Dual Battery Option

[nater]

Painless has come out with a digital option instead of their standard option that most of us are familiar with:

http://www.painlessperformance.com/webcatalog/largeview.php?SearchField=40120

It apparently is fully automatic on combining the second battery into the circuit. I like the fact that it will not allow the second battery to charge until the primary is fully charged.

Concerns are that if your primary has a drain on it, will it automatically combine in the backup battery, draining it too? This could leave you stranded pretty easily if your backup is drained without your knowledge.

About the same cost as the Hellroaring unit, and appears not to be as versatile, but perhaps for some people it may be useful

 

[TheMike]

Or, if you completely drain your primary, does it allow the second battery to be used for starting?

 

[nater]

Or, if you completely drain your primary, does it allow the second battery to be used for starting?

Mike, I am thinking it would not matter, since as you drain your primary, it would automatically connect your secondary, draining it also. By the time you went to start your truck, both would be dead...

 

[Youngunner]

Priority start to the rescue! Maybe?

Auto disconnects if voltage drops below 11.7 with the engine off.

http://www.prioritystart.com/

 

[ntsqd]

Mike, I am thinking it would not matter, since as you drain your primary, it would automatically connect your secondary, draining it also. By the time you went to start your truck, both would be dead...

I don't think this is correct. The other ACR/VSR's on the market sense the difference between charging voltage and battery voltage. They won't connect the second battery until the first battery is charged, and they disconnect when the charge voltage drops to just battery voltage e.g. when the engine stops.
I'm basing my guess on this:

The unit is designed to preserve the charge in the main battery for vehicle starting and control charging of the main and auxiliary batteries by the alternator.

 

[laxtoy]

taken from installation manual liked on the product page-
The Digital Power Manager is a weather-proof battery isolator and battery combiner. It provides Main
start-battery drain protection along with automatically combining two batteries for large electrical loads
such as winches, auxiliary lights, and other large electrical accessories. The DPM will also
automatically control which battery will be charged by the alternator first. Meaning the Main battery's
voltage must reach 12.6 volts before the Auxiliary battery will be allowed to charge.

my question to those in the know, does it seem to be as reliable as others such as a hellroaring on national luna kit? those kits recommend thicker gauge wire like 4 or even 2, and this is 6, does this seem like a draw back? are there any major flaws anyone can see? i certainly like the simplicity of the install and the price is pretty attractive as well

 

[ntsqd]

Remember that this is for controlling the charging of the batteries, not for starting. Wire gauge appropriate for the max alternator output is all that is required.

I've posted a lot about ACR's and VSR's and combining them with a boat switch or something like that.

No way to tell reliability until they've been in the field for a while.

 

[laxtoy]

sorry, but after a lot of reading today, my head is a little full. does that mean it doesn't leave you the option to start off the auxiliary if the primary is dead, as in won't take a charge? i imagine the case of this is always a rarity, and you would see some signs of this coming, but in the case of failure, what would you do, just pull the primary and drop in the aux?

 

[NothingClever]

Although I recognize there are far smarter men than me on the Forum who've authored excellent "white papers" on dual battery systems, my limited aptitude prevents me from getting to the next level of battery savoir faire.

I'll be installing an auxiliary battery in the rear of my vehicle (Tacoma...how unique, no?) which will be charged by an 85w solar panel and will never touch the starting battery (and vice versa).

 

[ntsqd]

There's a lot of good stuff here:
http://www.expeditionportal.com/forum/forumdisplay.php?f=48
Bound to be enough info to thoroughly confuse. :sombrero: