AGM for the Tow Vehicle

**jd1923** · March 13

I've asked about this several times over the last several years. Asked the owner of our local Batteries Plus, are AGM batteries better for our trucks? The answer in the past and since is "Yes, better but not worth twice the money!" I've had AGM batteries in my motorcycles over 10 years now.

The Dodge Ram Cummins always had two (2) Group 27 LA batteries. The last Dodge Cummins I had for 18 years had the same setup and twice I purchased the very reasonable Walmart EverStart batteries. Could have done the same this time for $150 ea. I searched for other batteries and the Odessey AGM came up $384 ea. Wow, like I said more $$$. In this case, should I pay $325 total with tax or $832. Go figure.

Then I found a new style EverStart AGM from Walmart, however they did not have the Group 27 size in this model. I found the H7 size to be very close to the Group 27, about 1/4" longer and wider, yet a full inch shorter in height. I purchased two of these modern AGM batteries: EverStart Platinum AGM Automotive Battery, Group Size H7 / LN4 / 94R 12 Volt, 800 CCA 140 RC - Walmart.com

They're made in South Korea, like that much better than China. South Korea manufacturing started earlier than China and is more mature in quality practices. Total OTD with tax $390 for two HD AGM truck batteries nice!

**jd1923** · March 13

I also purchased new battery terminals, crimped new lugs on all cables and new battery hold-downs, since they were all pretty crusty (see pics). The new batteries did not fit the OEM hold-downs (new Dorman hardware), so if you look closely, you'll see I had to rig some inserts to hold them tight.

I went with Military style terminals. First experience with these, and I love them! I purchased this item but would make another choice next time. Great terminals, the rubber covers are decent, but the lugs and heat shrink were not of best quality. Dodge Cummins Military Dual Battery Terminals, Lugs & Boots | eBay

These terminals have a 3/8" bolt end, so use 3/8" lugs on all your cables. The other side has a 5/16" bolt to tighten the terminal on the battery post. The beauty and simplicity here is that you can keep the 3/8" cable end held tight, and merely loosen the 5/16" nut to remove it from the battery. I've been fighting cables on dozens of vehicles since the70's! I purchased another couple of sets to use on our other old cars and trucks in the future, to be installed each time we need a new battery.

The other thing about Group 27 vs. these H7 AGMs is the posts are in reverse orientation. In making all new connections I had the change the +/- location of all cables. The main + cable, connecting the two batteries, mounted over the radiator core had to be shifted about a foot over. I had to make a new cable from the LH battery to the power distribution box, but most other cables had room to move 10" left or right.

I think it came out pretty good. The AGMs should last much longer. Every time I park the truck voltage is 13.1V or better, where LA is usually 12.6V at best. Let it park for a few days (and I have a cellular router running, rid-rat devices and more) and it's still at 12.9V. Love the AGMs! What do you think?

**ScubaRx** · March 13

Looks good...

**MAX Burner** · March 13

Always love a clean engine bay!!! Nice looking compartment, @jd1923! Well done, brother!

**jd1923** · March 13

7 hours ago, MAX Burner said:

Always love a clean engine bay!!! Nice looking compartment, @jd1923! Well done, brother!

Did a thorough cleaning when we purchased the truck (it is 23 years old). The engine compartment picture shows the old battery. Look how bad the terminals were in contrast. Thank you @ScubaRx and @MAX Burner! 😂

Rolind · March 13

Did you have to change the charging profile in your truck? I know sometimes, depending on the truck and the recommended charging parameters for the battery, the truck won’t fully charge the battery. Some AGMs like a higher charging voltage than flooded lead acid batteries.

**jd1923** · March 13

29 minutes ago, Rolind said:

Did you have to change the charging profile in your truck? I know sometimes, depending on the truck and the recommended charging parameters for the battery, the truck won’t fully charge the battery. Some AGMs like a higher charging voltage than flooded lead acid batteries.

Thank you for posing this question. I had a similar thought the other day, that perhaps I need a "Battery Tender" designed for AGM, to perform a final charge. Maybe I could plug it in once a week...

The many chargers I have now are all old-school automotive chargers for lead-acid. Walmart sells this as an automotive starting battery, meaning to be charged by automotive alternators. I didn't think it was enough of a concern, since by alternator there will still be more voltage than a lead-acid. They claim their AGM will have twice the life of the LA made by the same S. Korea manufacturer.

I will look for a technical support number and see what specs they have. I will post here later with whatever I learn and also my experiences as these batteries get more used. Thanks again!

**jd1923** · May 19

On 3/13/2024 at 2:21 PM, Rolind said:

Did you have to change the charging profile in your truck? I know sometimes, depending on the truck and the recommended charging parameters for the battery, the truck won’t fully charge the battery. Some AGMs like a higher charging voltage than flooded lead acid batteries.

It's been two months now and I have a few thoughts. There is no way a truck alternator can supply the same charge curve as a dedicated charger can installed in an RV. I have an accurate voltmeter and while driving I get mostly 13.7V, then 13.2V and the highest was 14.1V (rarely). I may need to install a new HD alternator, especially if I install a DC-to-DC charger. Voltage an hour or so after driving is usually 12.6V, sometimes 12.7V which is a hair better than lead-acid batteries. It's not the 13.1V that I used to get in our Class-C AGM house batteries.

I also have a Rid-Rat device and a Pepwave router setup in the TV, running 24x7. At home when the truck sits for a couple weeks the voltage can get down to 12.1V (lowest reading). I have a toggle switch for the router, but this is with it running.

I bought this charger and the hardwire kit and it has an AGM setting. Seems like a very nice unit. I have collected 5-6 chargers through the years, but all old technology. This will get the two truck batteries up to 12.9V, again an hour or so after disconnected. They say you can leave maintenance charger on for extended periods, but I don't as many will fry the batteries at some point. I extended the hardwire kit, so that the terminal is sitting in the air intake in the front bumper. I can charge the TV now without popping the hood. That's nice. I plan to charge it overnight every few weeks to keep these AGMs in good shape. 😂

Amazon.com: NOCO GENIUS10, 10A Smart Car Battery Charger, 6V and 12V Automotive Charger, Battery Maintainer, Trickle Charger, Float Charger and Desulfator for Motorcycle, ATV, Lithium and Deep Cycle Batteries : Automotive

Amazon.com: NOCO GC008 X-Connect M10 XL Eyelet Terminal Accessory Genius Smart Battery Chargers : Automotive

Edited May 19 by jd1923

**MAX Burner** · May 19

4 hours ago, jd1923 said:

I may need to install a new HD alternator, especially if I install a DC-to-DC charger.

JD - if poss, check-out any available "smart" alternators for your vintage TV. The new tech DC/DC chargers like them a lot... you might be able to get a 50amp model for your OTT in conjunction with a new smart alternator, just think'n out loud...(only into my 2nd cup 'o Black Rifle)

**johnwen** · May 19

32 minutes ago, MAX Burner said:

(only into my 2nd cup 'o Black Rifle)

**MAX Burner** · May 19

@johnwen - Right on, brother! "Blackbeard's Delight", this morning!

Hey, @mossemi - try out the BR sample yet? Y'all travel safe - see ya down the road...

Best,

A & D

**jd1923** · May 20

OK, the first mention was OK @MAX Burner, but you guys are turning my AGM in the TV thread into a dumb coffee thread!

**Ronbrink** · May 20

Nothing like standing at your TV while mulling over an AGM install with a good tasting cup of coffee in hand. Life is good!

**MAX Burner** · May 20

@johnwen

14 hours ago, jd1923 said:

you guys are turning my AGM in the TV thread into a dumb coffee thread!

HA, my bad, brother! Mea Culpa!

**johnwen** · May 20

14 hours ago, jd1923 said:

OK, the first mention was OK @MAX Burner, but you guys are turning my AGM in the TV thread into a dumb coffee thread!

My apologies, JD...

**jd1923** · May 20

Don't take me too seriously, just poured a cup myself! 🤣

**SeaDawg** · May 21

Morning coffee = camping lifeblood, for many of us... brain food.

Edited May 21 by SeaDawg

**Ronbrink** · May 21

10 hours ago, SeaDawg said:

Morning coffee = camping lifeblood, for many of us... brain food.

Agree, here’s to our morning ‘transfusion’ with a ‘dose’ of Oliver forum to boot!

**Geronimo John** · May 22

On 5/19/2024 at 2:12 PM, jd1923 said:

OK, the first mention was OK .. but you guys are turning my AGM in the TV thread into a dumb coffee thread!

Crazy Horse says "Me thinks JD will receive burning arrows when he hijacks another's forum."

But there is always hot coffee in my teepees.

At home or on the trail

Edited May 22 by Geronimo John

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