Anyone using Lithium under the hood as the Main Battery?
 

2003 2door RWD Blazer

Just wondering what Lithium battery I could fit under the hood. I'm looking to majorly upgrade the electrical for a 3-4000 watt audio system. I have eyes on a 400 amp Mechman alternator. Also thinking I could extend both side post terminals (without cutting off the factory "harness") with a top post adapter Like This one to add a distribution terminal to the lithium battery top.

Just wondering if anyone has done a little something like this in their Blazer. Any and all answers are greatly appreciated!

Would not using a lithium battery require a different type of charging system?

FWIW I was able to install an Optima Yellow-Top battery in mine.

I don't thiiink it would require any changes in the charging system with a lithium battery. But, what Optima do you have under your hood? And did it just drop right in or did you have to modify the battery tray?

It took me a moment but I was able to find my post on my Optima battery. It was an Optima D34-78.
https://blazerforum.com/forum/builds...100251/page14/

It was a tight squeeze requiring proper over-the-top hold-down hardware which I see as an upgrade. The stock hold-down mechanism consisting of the wedge that holds the battery in place at the base would not work due to the dimensions and shape of the battery. As the post notes, I had to drill a couple holes in the sheet metal for the hook parts of the threaded rods that are part of the hold-down hardware. You'll have to take the battery tray out to do this. But this is a good opportunity to clean and repaint the battery tray. I've since added protected power taps to the top electrodes for convenience and to power a small portable winch that I have.

Be sure to post what you learn about any special charging requirements for lithium batteries.

Lithium not a good idea if your in a climate where freezing temperatures are expected.
Lithium batteries should not be charged if battery temp is low.
Also some Lithium batteries have heating elements to keep warm in cold ambient temperatures. A few cold days with out charging could discharge batteries.
400 amp alternator and 4/0 cable will handle moderate lithium battery bank without issue, stock type alternators and stock wiring are not designed to supply the prolonged high amperage that lithium batteries draw during charging.

Ok that makes sense, it's probably why I hadn't seen too many posts about people having lithium under the hood. So AGM under the hood it is. I plan on upgrading to a 400 amp Alt and 2/0 OFC welding wire all around for now. I sure appreciate it.

I wouldn't use welding cable...
Spend a few more bucks and use marine grade high temperature cables. Marine wire is tinned to prevent corrosion and the jacket is resistant to oil.
Also fuse the cable between alternator output and battery terminal. You dont want a 400 amp fire , fed from alternator or from batteries.

That is a hell of suggestion to go with Marine Grade, I appreciate that for sure. Will definitely fuse between alt and battery terminal. Just ordered a 400 amp Mechman Alt. It's B-stock currently $465 shipped if you're looking for one too on their site. I think they have a few left

There is an excellent online calculator for 12 to 48 volt DC wiring. Look up Blue Sea Systems and use there free calculator, Circuit Wizard.
Also has lots of best practice info.