Novak Conversions Jeep Wrangler TJ engine mounts

New battery

Roger Dunning

Roger Dunning

TJ Enthusiast
Original poster
Joined
May 9, 2025
Messages
116
Location
Chichester, West Sussex, UK
I’m looking at a replacement battery. Mine is still working but my local garage said that the performance of it is not up to scratch. I’m someone who uses my jeep mainly for short journeys and it may go a few days before I use it.

I’ve researched this so much and it seems like the ultimate battery is the

Odyssey ODX-AGM34 (34-PC1500) 12V 68Ah 850A AGM Starter Battery​


Has anyone got any opinion?

These are £300 in the UK which is top money. Is it worth it and is this the best battery in the first place?

IMG_1378.png
 
Good battery. When I had the LS conversion done on my JKU the business owner recommended an Odyssey over an Optima. It still had that battery in it when I sold the Jeep

My TJ currently has a house brand AGM battery I got from a local parts house. Works great.
 
AGM batteries typically need a higher charge voltage than the TJ alternators put out to charge properly. The TJ regulator is designed for standard lead acid batteries. I've used AGM in the past on my 97 but they've never lasted longer than standard batteries. I got my last battery for less than £50 with a discount ebay gave me.

Tayna batteries supply various brands and are generally cheaper than elsewhere. They charge £8 for next day shipping on their website, but also sell on ebay, where batteries might be a couple of quid more but have free shipping. I've had my last three batteries from their ebay store I think. In case you're thinking I've had a lot of batteries, I've had my tj for 26 years now.

https://www.tayna.co.uk/
https://www.ebay.co.uk/str/taynabatteries
 
If you have the battery temp sensor, it will provide a charging voltage that should be good for an AGM.

If not, the charging voltage will be on the low side for an AGM.
 
The battery temperature sensor is a variable resistor which the ECU receives a voltage signal to adjust the charging rate when the battery temperature is cold/hot.
The battery should not be charged at a higher amperage charge rate during very cold temperatures since this will damage the battery.
Not sure what temperature (sensor resistance) the ECU is looking for to adjust charge rate to the higher voltages, but if you knew this temperature (sensor resistance) you could replace the battery temperature sensor with a fixed rate resistor to increase the charging voltage.
AS A TEST: You could remove the sensor from the battery tray and expose the sensor to a cold temperature (30-40*) and measure the resistance of the sensor, install a resistor of that value into the sensor wiring and see what voltage the ECU adjusts the charging to.
 
CharlesHS said:
Not sure what temperature (sensor resistance) the ECU is looking for to adjust charge rate to the higher voltages.
Click to expand...

My 97 w/battery sensor charges at 12.9 to 13.5 depending on RPM.

Adding a 40k resistor gets the charge voltage to 14.2-3 at 3k plus.

That's still low for AGM and unless you're running down the freeway not going to provide constantly higher voltages.

I have an Optima Yellow top and I'm happy with it.

But because the Jeep won't properly charge the battery I usually plug it into a maintainer when I park it in my shop.

Theoretically you can use HP Tuners to adjust the charge voltage.

I've also theroized about using a small lithium ion battery as the starter battery and connecting the AGM through a DC to DC charger.

-Mac
 
  • Like
Reactions: AOSJ
Mac,

Many years ago (20+) I swore by Optima batteries and then around 2001 I started having problems with them not lasting more than 1-2 years.
After some research I found that their production was moved to Mexico where they had sub par ventilation on the production line.
Supposedly this problem has been resolved, but I had continued to hear of problems with battery quality.
When they were still available I was using Sears Die Hard Platinum AGM which was an outstanding battery, but production of that battery ceased several years before Sears went bankrupt. It appears that Sears sold their rights to the Sears Die Hard Platinum AGM, but I have not tried this version.
Since then I use NorthStar and Interstate batteries.
 
  • Like
Reactions: macleanflood
jeepguy03 said:
The Interstate in my 98 TJ is from early 2017, I wish there was a local place that sold them for when I need to replace it.
Click to expand...

Interstate is pretty heavy on supplying shops instead of parts stores, may want to pop on their dealer finder, probably one pretty close.

With the quality of batteries now-adays, I've changed to making sure I buy from somewhere that will be open to replace one under warranty anywhere in the country. Autozone, Oreillys, Wal-mart, etc.
 
  • Like
Reactions: jeepguy03
I have that exact battery. It is an outstanding battery. I did have mine fail early, but got a warranty replacement from Odyssey. I don't think I will pay the premium next time for another Odyssey though. A good alternative is a Dekka battery if that is available in your area. A premium battery charger is essential for these batteries. I use a CTEK 7200. Whatever you buy, make sure you can easily warranty it if needed.
 
I was going to buy one of the "fancy" batteries, but after watching this... just got one from the local O'Reilly's...

Not sure what is available across the pond though.

 
GATORB8 said:
Interstate is pretty heavy on supplying shops instead of parts stores, may want to pop on their dealer finder, probably one pretty close.

With the quality of batteries now-adays, I've changed to making sure I buy from somewhere that will be open to replace one under warranty anywhere in the country. Autozone, Oreillys, Wal-mart, etc.
Click to expand...

Yeah that is a big factor, and likely what I will do for a replacement. I did see some shops around me that carry Interstate, but they are automotive repair shops not parts stores.
 
  • Like
Reactions: GATORB8
jonny jeep said:
IIRC, the FSM seems to disagree with this statement. It says charge voltage is increased at colder temperatures.
Click to expand...

My battery tender also has a "cold weather" mode that charges at a slightly higher voltage for colder temperatures and AGM batteries according to the manual.
 
CharlesHS said:
Mac,

Many years ago (20+) I swore by Optima batteries and then around 2001 I started having problems with them not lasting more than 1-2 years.
After some research I found that their production was moved to Mexico where they had sub par ventilation on the production line.
Supposedly this problem has been resolved, but I had continued to hear of problems with battery quality.
When they were still available I was using Sears Die Hard Platinum AGM which was an outstanding battery, but production of that battery ceased several years before Sears went bankrupt. It appears that Sears sold their rights to the Sears Die Hard Platinum AGM, but I have not tried this version.
Since then I use NorthStar and Interstate batteries.
Click to expand...

you didn't ask me but I have an Optima red top in my old Ranger that has a scoach more than 2 years on it and is much stronger than any lead acid battery I've had in it - electronics are very minimal in it, just like in a TJ, but I do run a 300w single channel amp to power a subwoofer

I've had the Ranger for 16 years and always got just about exactly two years out of a lead acid battery - this Optima Red Top just passed two years and is cranking like new - we'll see, but I certainly expect 3 years at least out of it - the red top was a customer return I got for 40% off, otherwise I don't think I would've bought, but at that price I wanted to try it
 
AOSJ said:
you didn't ask me but I have an Optima red top in my old Ranger that has a scoach more than 2 years on it and is much stronger than any lead acid battery I've had in it - electronics are very minimal in it, just like in a TJ, but I do run a 300w single channel amp to power a subwoofer

I've had the Ranger for 16 years and always got just about exactly two years out of a lead acid battery - this Optima Red Top just passed two years and is cranking like new - we'll see, but I certainly expect 3 years at least out of it - the red top was a customer return I got for 40% off, otherwise I don't think I would've bought, but at that price I wanted to try it
Click to expand...

Good to hear the Optima is working for you...
The manufacturer may have resolved the problems with their production process, but I will steer clear of Optima since there are other quality batteries (Interstate and NorthStar) to choose from.
 
Last edited:
Novak Conversions Jeep Wrangler TJ engine mounts
Top Bottom
Back