The Group 49 AGM Battery - If it fits, it sits!

I have been absolutely loathing the battery market at present, I'm looking at you 27F... There's no affordable AGM options out there in 27F, and it's maddening, watching all the other trucks get the nice $200 ones and we're out here shelling out $400+ for the X2 and similar.

I did post this before as to whether or not anyone else had done a slightly longer battery. I found an ancient post on YouTube from ********* doing something else entirely including, good lord, butchering his battery wiring harness and using the worst connectors known to mankind, but the battery he was using was similarly longer like the group 49, so I dug into a test fit.

Step one, procure the appropriate AGM battery, Group 49 Duracell Ultra Platinum AGM (model SLI49AGM) with 850 CCI, 92 AH, 4 year warranty. $259 minus 10% discount code, total of $254 after core refund and etc. This places it at exactly $38 more than the equivalent Duracell Gold flooded acid battery with 710CCA in 27F, so the money's making a lot of sense so far. Grabbed a new tiedown bar from our man Coupe here, and some much nicer battery terminals. The terminals ended up being a complication later and I'll get into that.



So there's a nice battery. Didn't come fully charged, hilariously enough, so I put it on my AGM-compatible motorcycle battery charger overnight and life's good.

Here's the battery tray, I decided to leave it, and threw a layer of rubber down at the bottom so the battery's not just resting on the edges of the tray. I also drilled a couple drain holes in the tray, keep water from being retained there. When my lead acid battery started leaking I did clean things up best I could, kinda hosed down my battery area with the anti-corrosion stuff from CRC, so ignore the gunk everywhere. I cleaned this area up much more nicely after everything'd been dry fit once.



With the battery sat on the tray, the moment of truth - will it fit with a large enough comfortable margin? ... yes! Leaves about 7/8th's inch of a gap on the motor side of things, which yes, is less than the 2 inches it had previously, but still, pretty decent.





I buttoned up everything and... ah what the hell. These battery cable leads are 90-degree angles and my new terminals are not. So I had to do a bit of shoving and wiggling on the battery leads to get things to fit into place. I will go back and clip off the OEM battery terminals and install some nice all-copper or copper-tinned 2ga heavy duty terminals, I have a nice hydraulic crimper that'll do the job, but for now, things fit snugly if not a little awkwardly.



I did a test drive and checked the gap after a few good bumps and gaps. This tiedown from Coupe is some heavy duty stuff, gotta say. The Group 49 has a gap in the middle, so I used the rest of my spare rubber sheet and filled that gap, and everything cinched down super tightly didn't budge a spare millimeter in any direction.

So final takeaway thoughts on this:

• It fits, at least to my fairly amateur eye, just as well as I could have hoped. It doesn't stick out any further than the cabling securing it on the left.
  
  
• If you're smarter than me about the battery terminals you select, or if you can reuse your stock ones, you can get away with not needing to clip and remount your battery cables. I will need to do this because I don't like the cable angles I ended up with, but it does indeed work.
  
  
• Group 49 AGM battery is 60lbs, 27F flooded is just shy of 50 lbs. Neither's exactly a LiPO featherweight but it's a thing.
  
  
• This battery is a little shorter height-wise than the 27F but it IS pretty easy fitment.
  
  
• I do not know if my aftermarket headlights contributed to the easier fitment of this battery. I'm using some inexpensive AlphaRex Pros and they've been good to me, certainly better at their job than the OEM reflectors than came in my '16 OEM, and I don't know if they're as deep or not as, say, the OEM reflectors, the OEM LEDs, etc. We'd need to compare that against what I've got here to see if that's a contributing factor or not, but honestly - I suspect not.

Here's hoping the long run proves to be a neat $200-ish saved!

 

Sits a little close to the motor, but seems ok otherwise. Does it need any additional heat shielding? Batteries are an absolute racket these days. When I replaced my golf cart batteries, it needed 6 - 6 volt batteries. I put 3 -12 volt golf cart batteries in instead. They said it wouldn’t work and the range would suffer, but they were wrong! Works fine. Saved $500. Gotta be crafty sometimes people. Good job.

 

I don't know if it'll need any additional heat shielding, but if it does, I've got some super-long stainless steel zipties and there's plenty of those reflective heatshield mat things to go around! I don't have an extra temp probe hanging around, but I can source one when summer rolls out here in MN in like 4 months, ha.

 

Nice swap. The group 49 is also know as the H8. European cars have been using the DIN H series for many years now. The 2022 Tundra uses the H7, which is the next size down.

 

Follow-up on this after 2 tanks of fuel on a road trip and some light wandering over some back roads, curbs and stuff - battery's still snugly in place, paint pen marks still aligned so it hasn't shifted at all, and doesn't warm up the edge of the battery that's a little closer to the engine. I might still stick some of the foil around it anyway, it's cheap, and it's only running what 55F here right now.

Now that I'm running AGM I wonder if I should do the diode upgrade thing I remember reading about? I'll have to find a thread or two on it.

Edit: Anyone used one of the Voltage Boosters? It brings up the important aspect of retaining the fuse which the diode mods don't do, and I like fuses being present.

 

Nice write-up..
Just curious, why do you feel you needed an AGM battery at all?

I had a 24F X-Power and it was nothing but a PITA..
Traded it for $20 core charge to get my Interstate MTP 27F and never looked back.



That said, I did run the HKB fuse while I had the AGM.
It did up the amps to 14.1 - 14.5 when charging.
However, it didn't stop the X2-power from dying twice in 6 months.
The Interstate is still running strong...

Hope you have better luck than I did..

 

Awesome!!!

Mind sharing where you sourced the battery from???

now here’s some quality terminals I’ve been using for about 7yrs in various applications

no need to hack anything

if your cables won’t reach you can put the screws in from the bottom also


https://gpcaraudio.com/gp-audio-v2-sae-style-6-spot-machined-battery-terminals/

 

I currently have an H6 in my truck. Not by choice…
Truck battery died while gassing up my boat and the station attendant was kind enough to use a jump box and got me started.
There was a WalMart across the street from the gas station so I headed over there. Of course, they were out of the 27 size with the proper terminal configuration, so checked out the H series and ended up buying one. It had more CCA and reserve cap than the original and ended up being a little longer, but essentially the same height and width.
That was ~2 years ago and no issues.