Electrical Upgrades: Round 2 – Odyssey AGM Battery

It’s been a while since I’ve done anything with the electrical system on the LJ.  Thankfully that’s because everything has been working just fine <knocks on wood>.  That said, a recent addition to the Jeep led me to upgrading the battery on the Jeep.

Had to go to the local freight terminal to pick up this load of goodies.
Good thing the back of the Jeep was empty while I work on the new rack some more.
Also a good thing this was a small pallet.

To be honest, there was nothing wrong with the NAPA brand battery I was running.  It’s a solid battery but it’s still a lead-acid battery.  It’s also only a 750 CCA battery and the reserve capacity is relatively low.   Read on to find out why I replaced a perfectly good battery…

One thing leads to another

I recently obtained a new Warn 9.5xp self-recovery winch (more on that soon).  With the potential increase demand in power draw I felt it was time to upgrade my battery.  I also want to upgrade the batteries on the trailer (more on that soon too) and I figured it was time to just upgrade all the batteries.

My old standard lead-acid battery.
Not a bad battery by any means, but I’ve been wanting to switch to an AGM for a long time.

AGM (absorbed glass mat) batteries are nothing new in the 4×4 world. They have some marked advantages over a standard lead-acid automotive battery. First they are fully sealed meaning they won’t leak when tipped on their side or inverted.  Second, due to their construction they are more resilient to vibrations making them less prone to failure in the rough and tumble world of off-highway travel.  Also, premium brand AGM batteries like Odyssey are often more powerful and perform better than comparably sized lead acid batteries.

Why Odyssey Batteries

I chose Odyssey for two reasons, first their international headquarters is based here in PA just over an hour or so away from me.  We all know my affinity for American owned companies and I’m partial to those based here in PA.  Second, they are one of the industry leaders in automotive batteries.  They make a quality product with a proven track record and pretty good customer support.  When I asked around what batteries people preferred, Odyssey was at the top of the list.

Choices, choices, choices.
As you can see, it’s not just about bottom dollar cost.
Three things I was concerned with were power to weight, power to size, and power to cost ratios.
Odyssey 1500 series was the clear winner on all three compared to the other popular Group 34/78 AGM’s on the market.

The other reason I chose Odyssey Batteries was because of their wide range of offerings when it comes to batteries.  During my selection process I went so far as to create a spreadsheet of the different battery sizes, their overall dimensions, weight, and power output.  I also decided to look at some things like power-to-weight ratio and power-to-size ratio for my own comparison sake.  Lastly, I compared a few different manufactures of batteries and looked at the power-to-cost ratio.

I’ve always said you can judge a company by how well they package their products.

While nothing more than a simple cardboard box, they obviously put a lot of thought and effort into sizing everything.

Also included with the battery were the appropriate product and brand materials.
And of course a sticker!

The other thing I like about Odyssey Batteries is how well constructed they are.
The handle on some cheaper batteries seems like an after thought.  This one is beefy and secure.
Also look at the dual posts on the 34/78 series battery and how well built they are.

Installing the battery

With the old battery out you can see there isn’t much difference on the outside between the two batteries.
Both are group 34/78 size batteries.
Both are also heavy as hell.
Here you can see the basic stats of the old Napa brand battery.
Not a bad battery by any means.
I’m sure this battery will end up in one of the other family vehicles.

For comparison’s sake, here are the stats for the new Odyssey.
You can see it has an additional 70 CCA (cold cranking amps) which goes a long way on something like a Jeep.

One of the things I noticed right away was the difference in terminal placement.
If you look at the photo above the terminals for the Napa brand battery were more central to the body of the battery.
The ones on the Odyssey are closer to the edge.  I didn’t like how this looked.
Luckily during round 1 of the electrical upgrades I opted for these military/marine style terminals.

With the terminal studs switched around I was able to spin the terminals 180.
This moved the wires in more and away from things like the hood (positive side) and the a/c condenser line (negative side).


The first thing I noticed was how quickly the Jeep fired up.  In the past the Jeep would start with an expected level of effort. I am, after all, starting a 4.0 inline six off an electric motor off a battery.  However with the bump in CCA’s and the better construction of the Odyssey Battery the Jeep fired up with a noticeable amount of ease.

The only issue I have right now is that the Group 34/78 Battery has a slightly smaller foot-print than the stock battery tray in the LJ.  Not sure what the exact size should be (there was a Group 34/78 in it when I got it – and I’ve always run 34/78 batteries in my Jeeps) but a small adapter will be needed to secure the battery 100%.  In the meantime the stock hold-down bracket is doing the trick.

Beyond that I am already 100% pleased with the upgrade.  The only things I need to do next, in terms of the Jeep’s electrical system, are an auxiliary fuse/relay box and then tidy up some of the wiring.  I also want to swap out one of the in-dash 12v sockets for a dual-USB plug to make charging things like my iPhone and iPad a little easier.

If you’re wondering what is going to happen with the other two Odyssey Batteries I got, they are going to end up in the trailer.  Before I can do that though I need to sort out a mount, a dual-battery management system, a battery monitoring system, as well as a few other smaller odds and ends.  Most importantly though I need to figure out WHERE the batteries are going to go.  I’d like to do a tongue-box but that means finding one.

I plan on carrying this in the trailer to serve as a shore-power system.
It will also help keep the trailer batteries charged and conditioned while the trailer sits idle between trips.

The other item that came with the batteries was one of the Odyssey brand chargers.  This will help keep the batteries healthy and also double as a way for me to tap into shore power (120v) when possible.  Always a good idea to have something like this on hand to make sure you protect the investment you make into good deep cycle batteries.

For more information, visit the Odyssey Battery website:


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