william_7900
Registered Member
I want to first thank everyone for helping me figure out how to setup up a very simplistic and (almost) foolproof dual battery solution.
From what I've read, there seems to be 2 main reasons for having dual batteries.
Because of this risk, it came down to going with one of two tried and true solutions - an isolator or the ACR. I settled on the ACR for the following reasons.
The isolator would/could cause a voltage drop to the batteries because it is basically diodes controlling the flow of voltage (one way only); and the ACR automatically puts the batteries in parallel where the isolator doesn't.
The ACR automatically puts the system in parallel unless one battery has too little voltage or is being over-charged.
I originally decided to stay with the solenoid solution as I had that wired up and working. Unfortunately, the wire on the back of my alternator became loose causing both batteries to slowly discharge. When trying to leave the local tire store, my Blazer would only click (kind of like the blue screen of death for the computer geeks on this forum).
I got out my trusty jumper cables thinking I was going to jump from my charged 2nd battery (oooos and ahhhs at my cool dual battery setup from the guys at the store) but the ooos and ahhhs were short lived as my 2nd battery was just as low as the primary because the solenoid kept the batteries in parallel so they could both discharge together... :-0.
The design I ended up with was drawn up by Ryoken - I just touched it up a bit.
I kept the solenoid in the system to disconnect the 2nd battery (deep cycle) from the ACR when the engine is turned off but I think that is not a requirement.
Some general facts I learned along the way...
My alternator needs an Excite wire in order for it to create voltage to charge my batteries.
A solenoid is basically a switch that is turned on and off by completing a 12 volt circuit (the two small terminals on a solenoid, one provides 12v and the other connects to a ground).
Voltage provided by the alternator will automatically flow to the battery that needs it.
You can use deep cycle and non-deep cycle batteries together but they need to be disconnected from each other when no charge is being provided to the system (the engine is turned off).
You can use a solenoid but you need to get a continuous duty solenoid instead of a typical starter or car solenoid.
A good rule to follow is to connect accessories (radios, winches etc...) to the auxiliary battery instead of the primary.
Another good rule is to ground the 2nd battery's negative terminal directly to the primary's negative terminal and to ground the primary directly to the engine.
The items I purchased:
The thread where this was discussed in detail:
http://coloradok5.com/forums/showthread.php?t=242156&highlight=dual+batteries
Additional info:
http://surepower.com/pdf/isolator1.pdf
http://bluesea.com/category/2/productline/overview/389
http://bluesea.com/viewresource/58
http://www.wmjmarine.com/c16580.html
http://order.waytekwire.com/scategory/M37/260/200
http://bluesea.com/files/resources/i...tions/6693.pdf
From what I've read, there seems to be 2 main reasons for having dual batteries.
- To isolate an auxillary battery to run audio/video etc... without compromising the primary (starting) battery;
- To put the batteries in parallel to provide more amperage to a winch (which is what I am doing) or other devices.
- Basic parallel (positive to positive, negative to negative)
- Using a solenoid to separate the batteries when the engine is turned off (a solenoid is just a switch that is turned "on" using the two small terminals)
- Using an Isolator
- Using an ACR (Alternator charging relay)
Because of this risk, it came down to going with one of two tried and true solutions - an isolator or the ACR. I settled on the ACR for the following reasons.
The isolator would/could cause a voltage drop to the batteries because it is basically diodes controlling the flow of voltage (one way only); and the ACR automatically puts the batteries in parallel where the isolator doesn't.
The ACR automatically puts the system in parallel unless one battery has too little voltage or is being over-charged.
I originally decided to stay with the solenoid solution as I had that wired up and working. Unfortunately, the wire on the back of my alternator became loose causing both batteries to slowly discharge. When trying to leave the local tire store, my Blazer would only click (kind of like the blue screen of death for the computer geeks on this forum).
I got out my trusty jumper cables thinking I was going to jump from my charged 2nd battery (oooos and ahhhs at my cool dual battery setup from the guys at the store) but the ooos and ahhhs were short lived as my 2nd battery was just as low as the primary because the solenoid kept the batteries in parallel so they could both discharge together... :-0.
The design I ended up with was drawn up by Ryoken - I just touched it up a bit.
I kept the solenoid in the system to disconnect the 2nd battery (deep cycle) from the ACR when the engine is turned off but I think that is not a requirement.
Some general facts I learned along the way...
My alternator needs an Excite wire in order for it to create voltage to charge my batteries.
A solenoid is basically a switch that is turned on and off by completing a 12 volt circuit (the two small terminals on a solenoid, one provides 12v and the other connects to a ground).
Voltage provided by the alternator will automatically flow to the battery that needs it.
You can use deep cycle and non-deep cycle batteries together but they need to be disconnected from each other when no charge is being provided to the system (the engine is turned off).
You can use a solenoid but you need to get a continuous duty solenoid instead of a typical starter or car solenoid.
A good rule to follow is to connect accessories (radios, winches etc...) to the auxiliary battery instead of the primary.
Another good rule is to ground the 2nd battery's negative terminal directly to the primary's negative terminal and to ground the primary directly to the engine.
The items I purchased:
- ACR
- Continuous Duty Solenoid
- Basic switch
- 2 gauge battery cable
- Various connectors
The thread where this was discussed in detail:
http://coloradok5.com/forums/showthread.php?t=242156&highlight=dual+batteries
Additional info:
http://surepower.com/pdf/isolator1.pdf
http://bluesea.com/category/2/productline/overview/389
http://bluesea.com/viewresource/58
http://www.wmjmarine.com/c16580.html
http://order.waytekwire.com/scategory/M37/260/200
http://bluesea.com/files/resources/i...tions/6693.pdf
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