Dual Battery Setups! Let's see them! Multiple Batteries Thread!

Edit: I was averaging 13.2 - 13.4v before relocating the VSW

 

I didnt get to chance to mess with anything today because I spent all day hunting but I did use my truck's headlights to light up 2 deer while we skinned them out this evening. The truck sat and idled for about 30 minutes or so, I got curious and popped the hood and low and behold, the ML-ACR was latched.

Hopefully I have some time to dig into it and check some shit tomorrow and get a better idea of whats going on.

 

seems like that would be too tight

 

Never mind that; how is it held down? Does the tray have a hold-down thingy at the base? You can probably run a nylon strap all the way around the battery and tray.

 

Relax everybody, that was just the first test fit of many. Measure twice, cut once.

 

You can do it more easily just by changing the ALT fuse: https://www.hkbelect.com/product/99-mk3-mini-blade-75a-electronic-fuse-version-2008/

My setup:

 

thats what I did. I had to remove the fuse for the winter, but it was great for the little bit I used it in the fall. Looking forward to the 14.6 volts in the summer!

 

Why did you remove it in the winter?

 

It was over charging. Getting up to 14.8-14.9 volts. My idling voltage in the winter with all stock stuff is 14.2 where in the summer it’s 13.7. That little bit of difference in the winter to summer messes with the new fuse. They do mention that you may have to take it out in colder temps.

 

It’s correct voltage at freezing temps for AGM battery.

 

Thats the proper voltage at that temp?

 

Potentially, yes. A good charger will have built-in temperature compensation. Does depend on the nature of your charging, float or cycling. But 2.5V per cell, or 15V, would fall somewhere within the right range for bringing a discharged battery back in bulk or absorption at lowered temperature. The charging system in a truck isn't temperature compensated as such but the battery characteristics change over temperature so the charging system is probably reacting to the state of charge.

 

So you’re saying you don’t need to remove it?

 

Not necessarily. I wouldn't float at ~15V though, so if that's what it's settling at with fully charged batteries and no load like headlights on it's probably too high.

 

Where is everyone mounting their Blue Sea switch and Peak DBI dual LED monitor in a second gen?

Looking for ideas for a clean OEM+ install.

 

Yes. This is for AGM:

 

That's pretty slick!

But for $50.00 I would rather spend the time relocating the VSW anyways while the fuse box assembly is open when swapping out the OEM alternator cable for a bigger gauge.

 

Interesting. The company states that if the charge goes over 14.6 or so that you should remove it. I have never had my charge that high with or without the fuse. I’ll have to look in to it. Thanks for the info.

 

14.6V is roughly correct for a flooded lead-acid at 25C (about 77F). For any given temperature AGM batteries should be charged at a slightly higher voltage than a flooded battery. So 14.8V is about right at 25C. As you go up or down in temperature you will adjust based on the temperature coefficient, thats why 15V is right for an AGM at 0C and 14.8V would be roughly right for a flooded battery. Also means at 35C you should be reducing the charging voltage, incidentally.