Dual Battery Installation

cdh027 · October 27, 2015

That may be why GM provides the space for the 2nd Batt on the 1500s even though there is no Batt upgrade available from GM....gives the police/fire/EMS upfitters a place to put their 2nd battery

Does anyone make a kit for installing the second battery with cabling and isolator ready to go?

mrbadwrench · October 27, 2015

Does anyone make a kit for installing the second battery with cabling and isolator ready to go?

Not for the 1500's.

But it's so easy you don't need a "kit". Basically you're just dropping in a battery, cutting 4 gauge wire to length, crimping on some battery post ends and hooking it up. And you don't need the isolator, but if you want it that's just as easy to install...just a couple extra connections.

mrbadwrench · October 27, 2015

By the way, the option code for the dual battery "kit" for the 2500's is TP2.

morrislee · October 27, 2015

You could have used the last free bolt under the black cover next to the red cover, I guess it is too late to tell you.....

mrbadwrench · October 27, 2015

You could have used the last free bolt under the black cover next to the red cover, I guess it is too late to tell you.....

That bolt is only rated to 125 amps though.

morrislee · October 27, 2015

You wont be able to run a microwave by the way, you are going to burn the wires out unless it is on a dedicated wire to a dedicated inverter.

Hmm...so I could run a sawzall off the 120 plug with this? I tried the other day and got no power...

You probably tripped the breaker AND the fuse, I did that when I made the mistake trying to run a mini vacuum.

morrislee · October 27, 2015

That bolt is only rated to 125 amps though.

Not a big deal for me, I ran mine in parallel and it is only used to make sure i can run radio and other items without worry. 125A is still a lot, 125A * 12V = 1500watts. cranking still comes from main, but the aux battery keeps it charged as they balance themselves out.

Unless you are actually running a larger equipment, I do not see any other case needing more than 125A unless you are cranking.

mrbadwrench · October 27, 2015

Well my plow draws about 170 amps under load, so that's why I figured direct connection without the 125A fuse in between would be best so that I can get the most from the 2nd battery...and not risk popping any fusible links Gm has in there.... But I'm not sure if it would actually matter since it's a secondary battery.

morrislee · October 27, 2015

Well my plow draws about 170 amps under load, so that's why I figured direct connection without the 125A fuse in between would be best so that I can get the most from the 2nd battery...and not risk popping any fusible links Gm has in there.... But I'm not sure if it would actually matter since it's a secondary battery.

Or attach the the plow to the second battery only? What is it powering really? just moving it up and down right? Not a constant draw, should be ok

mrbadwrench · October 27, 2015

Or attach the the plow to the second battery only? What is it powering really? just moving it up and down right? Not a constant draw, should be ok

Well it usually isn't more than momentary draw, but because it has downpressure it can be a constant draw. If I scrape a long driveway in downpressure mode, the pump is running constantly to force the hydraulics down. So that could be several minutes of constant operation. I didn't have any issues last winter on the single battery, but I'm just thinking 170 amps could cause problems if drawing from two batteries at once if the connection between the two batteries is weak. For example, I'm wondering now if 4 gauge wire is sufficient. Maybe 2 gauge is a better choice...

morrislee · October 27, 2015

Well it usually isn't more than momentary draw, but because it has downpressure it can be a constant draw. If I scrape a long driveway in downpressure mode, the pump is running constantly to force the hydraulics down. So that could be several minutes of constant operation. I didn't have any issues last winter on the single battery, but I'm just thinking 170 amps could cause problems if drawing from two batteries at once if the connection between the two batteries is weak. For example, I'm wondering now if 4 gauge wire is sufficient. Maybe 2 gauge is a better choice...

If you are plowing, chance it is that the cold is keeping the wires cool anyway. also depends on your wire length

Last C5 · October 27, 2015

Use an isolator, but not an electronic one unless your father in law owns an isolator factory and gives them to you for free. A standard Ford starter solenoid will do exactly the same thing and will outlast an isolator 20 to 1.

Edited October 27, 2015 by Last C5

SAKO79 · October 27, 2015

I have a 2014 Sierra 1500 and I installed at 9500 pound winch at a few light bars and I installed a 2nd battery over a year and a half ago why use the Ford solenoid and wired it all in properly it works great

fondupot · October 27, 2015

All duramax's have 2 batteries.

Yea for the glow plugs, so you aren't left stranded when its -15 degrees. But gas cars don't really need a second battery unless you are running all sorts of extra electronics. Like a winch, and lots of spot lights, maybe a hydraulic pump for a snow plow. etc.

redwngr · October 27, 2015

Yea for the glow plugs, so you aren't left stranded when its -15 degrees. But gas cars don't really need a second battery unless you are running all sorts of extra electronics. Like a winch, and lots of spot lights, maybe a hydraulic pump for a snow plow. etc.

And with the higher compression ratio, diesels crank harder than a similar cube gasser.