Installing dual batteries

I am installing a dual bat setup on my 2016 Tacoma. My question is whether the computer system will react if I just install a solenoid for a battery isolator, or does the truck require a smart isolator with diodes and do-dads. So can I simply run a wire from the alternator at the battery to the solenoid in order to charge the alternate battery while the engine is running? Also is there a specific wire I can tap too during engine running operation that will not register voltage with the engine off?

 

Great question !

 

...but what's the answer???

 

Don't have it lol !!! I'll be watching this thread as it's something I want also. I have a friend that did this ...but when I inquired he just said he would do it for me for cost of parts and a couple of beers . He figures it would be quicker if he just installed without my help .
He's obviously right !!!

 

It won't harm the vehicle at all. However for charging purposes to make sure both batteries are being charged correctly and will have a longer life, it would be best to get a digital battery isolator that will control both batteries instead of a normal or old school solenoid.

 

I have a new lead/acid battery and the existing is lead/acid of similar size so I want to save the money -a solenoid is about 1
$15 and a smart isolator is $75-100...

 

So first answer is go with the smart isolator
So far it looks like you need to be smart and go wth the smart !!
Can't wait for next answer !
You should do one of those survey deals smart isolator or cheapy isolator !

 

If my secondary battery is drained and begins to charge when the engine is running does the primary battery overcharge in the process?
Also can I take the existing alt wire off the positive terminal and run it to the isolator for an engine running voltage to operate the isolator allowing for both batteries to charge?

Sorry if i'm not clear here...

 

CONTACT OFF GRID ENGINEERING

 

The idea I believe with a smart isolator is the main battery will charge secondary and " isolate " the two when both are fully charged .

 

Thinking about this I need to find a "true ignition source" to trigger the solenoid when the engine is running. Where should I connect for that???

 

The isolator is easiest, it will have 3 threaded bits on top, one is alternator input the other is battery#1 out, and battery#2 out. When the truck is running they will both charge, it will keep it "isolated" so starting still goes off main battery and will not deplete the 2nd.

 

https://www.4wheelparts.com/Electri...a0X9gMceTXjTMhlfDxa4LEgWOzyFhaLYaArvrEALw_wcB

 

I see what your saying but if I use the solenoid I need a trigger voltage from the "ignition on" condition that reconnects the two positive posts so that the alternator charges both batteries.

 

So dont use the solenoid... just buy the isolator... its all you need!