Aux Battery Swap for H8 Main Battery

[eltaco]

When the aux battery dies it drains the main battery in a lot of cases leaving you with two dead batteries. Would be nice if they set it up so it would isolate the battery when it dips below 11 volts but that is not the case. With the RHO it seems to be two fold issue. 1 there are a bunch of guys who just got bad batteries. 2 Something in the system does not turn off or randomly turns on and kills what would be a good set of batteries. Option 2 happened to me last week when the truck decided to turn itself on at 10pm until it killed my batteries a little after 2am. Both batteries were down to 4 volts but took a charge in the morning and I have had zero issues since.

I can sort of write off the O2/cat issues as misfortune, but this battery issue has a lot of momentum behind it with so many similar reports. This one has me rethinking my RHO order in all honesty, as this is my only vehicle. No vehicle is perfect, but most RHO owners seem to have less than 5k miles on the odometer and already running into battery problems.

 

[MattH89]

I can sort of write off the O2/cat issues as misfortune, but this battery issue has a lot of momentum behind it with so many similar reports. This one has me rethinking my RHO order in all honesty, as this is my only vehicle. No vehicle is perfect, but most RHO owners seem to have less than 5k miles on the odometer and already running into battery problems.

Definitely not most. People typically don't go online to write a post every day their truck started as normal and had no issues.

 

[MurphNH]

I would not change my decision to buy this truck and absolutely love it. Go on any truck forum and you will leave feeling like you are about to make a horrible decision lol.

 

[eltaco]

Definitely not most. People typically don't go online to write a post every day their truck started as normal and had no issues.

Sorry, didn’t mean to write it that way.

Most RHO owners report less than 5k miles on their odometer.

Most are definitely not encountering battery issues, but those who are have very few miles on their vehicle.

Nonetheless, there’s some consistency to the issue and at least so far it doesn’t seem isolated to only a subset of the deliveries taken so far. I haven’t yet seen a clear resolution… which I suppose is why we have people swapping brand new factory batteries for larger H8s per this thread.

 

[MattH89]

Sorry, didn’t mean to write it that way.

Most RHO owners report less than 5k miles on their odometer.

Most are definitely not encountering battery issues, but those who are have very few miles on their vehicle.

Nonetheless, there’s some consistency to the issue and at least so far it doesn’t seem isolated to only a subset of the deliveries taken so far. I haven’t yet seen a clear resolution… which I suppose is why we have people swapping brand new factory batteries for larger H8s per this thread.

Agreed. More are having issues than should be. There's definitely some sort of fire with this amount of smoke

The weird thing is that it's not all. If it were the software or the architecture you'd expect everyone to be impacted. That leaves you to suspect hardware, but even that seems inconsistent.

It really is frustrating for those who are impacted. Knock on wood, mine has held rock solid 14.4 since delivery and I'm at about 1300 miles.

 

[cconnorhtx]

When I travel for over a week (semi frequently) I always put the main batter on my NOCO Genius 5 and it keeps it flawlessly charged - but, I have never done anything with the aux battery and just assume (yeah, I know) it's fine.

Would this dual bank NOCO Genius 5 be a way to keep them both tendered together, or is the aux battery different enough that this wouldn't work with it?

The permanent eyelets that attach to the battery make it a literal plug and play.

https://www.amazon.com/NOCO-GEN5X2-Fully-Automatic-Temperature-Compensation/dp/B08G3STB1N/ref=sr_1_7?crid=2ANC32NG1HV1I&dib=eyJ2IjoiMSJ9.eiLIpmPh2rIzvPzMVURsGYk675eRMCK566CN3umRutlFJ5lBj_uYHxLMsHgZ-iF5xhv_Y8hk5CVkQY-r6RuyY8ulF-nH7rBm1IVcT24jWMvbQuuKjxeZ_y9nPISXxhRhQ72YddQ6cX6XPplprJq5PUsX4GCwUtG1p_-LIdyzstolV4bby_BuGE3agf2jKRyHnypRSp7QcRBx2bTJu77LYxPrjo2Ke0OomXPHLCgXsPgRN5fVSFD6eTESKHpMJC_ZdbFijz5WcZaP-_it1mSd4Dhmnpj2VhjKwwXAnUc8G9uHBby9y8IqcSXxIIk3KKrdzEoLcFoAG_ytrUwA9hel-eERhuFi84-Hzd-Ri6zQXCxPoI5nAyiDL04M4Xwwav7AuKg1m5dsYMQOpRrYQOdbYZMogpTEaOPdSoMgLFBpY_QLOCP92M8KLrKC2GCIZ7eo._QSVvXAwIoAg0rfuOeTQ0eu5DasCj9oRs8EkFR5OeiE&dib_tag=se&keywords=noco+genius+5&qid=1741703393&sprefix=noco%2Caps%2C165&sr=8-7&ufe=app_do%3Aamzn1.fos.9fe8cbfa-bf43-43d1-a707-3f4e65a4b666

 

[moparfiend]

I'd like to know about that as well, do we need to hook up both to the charger or just primary?

What would be a better solution, if someone wants to figure out how to do the true dual full size battery's like the diesel 2500's/3500's have with voltage isolation option.. one can dream right

 

[mike12193]

When I travel for over a week (semi frequently) I always put the main batter on my NOCO Genius 5 and it keeps it flawlessly charged - but, I have never done anything with the aux battery and just assume (yeah, I know) it's fine.

Would this dual bank NOCO Genius 5 be a way to keep them both tendered together, or is the aux battery different enough that this wouldn't work with it?

The permanent eyelets that attach to the battery make it a literal plug and play.

https://www.amazon.com/NOCO-GEN5X2-Fully-Automatic-Temperature-Compensation/dp/B08G3STB1N/ref=sr_1_7?crid=2ANC32NG1HV1I&dib=eyJ2IjoiMSJ9.eiLIpmPh2rIzvPzMVURsGYk675eRMCK566CN3umRutlFJ5lBj_uYHxLMsHgZ-iF5xhv_Y8hk5CVkQY-r6RuyY8ulF-nH7rBm1IVcT24jWMvbQuuKjxeZ_y9nPISXxhRhQ72YddQ6cX6XPplprJq5PUsX4GCwUtG1p_-LIdyzstolV4bby_BuGE3agf2jKRyHnypRSp7QcRBx2bTJu77LYxPrjo2Ke0OomXPHLCgXsPgRN5fVSFD6eTESKHpMJC_ZdbFijz5WcZaP-_it1mSd4Dhmnpj2VhjKwwXAnUc8G9uHBby9y8IqcSXxIIk3KKrdzEoLcFoAG_ytrUwA9hel-eERhuFi84-Hzd-Ri6zQXCxPoI5nAyiDL04M4Xwwav7AuKg1m5dsYMQOpRrYQOdbYZMogpTEaOPdSoMgLFBpY_QLOCP92M8KLrKC2GCIZ7eo._QSVvXAwIoAg0rfuOeTQ0eu5DasCj9oRs8EkFR5OeiE&dib_tag=se&keywords=noco+genius+5&qid=1741703393&sprefix=noco%2Caps%2C165&sr=8-7&ufe=app_do%3Aamzn1.fos.9fe8cbfa-bf43-43d1-a707-3f4e65a4b666

That Noco is 5amps per bank. That is alot of amps for the little aux battery. What we need to see if with the truck off will the aux battery take a charge with just the main battery on the charger. I haven't tested yet. If it does "connect/charge both batteries" while the engine is off a single bank charger should "float" the charge to the aux battery too.

 

[MurphNH]

I would think you could hook up a battery charger and test with a volt meter on the aux battery. You should see that it gets charged also but the one issue I see is if the main is at 12.5 lets say and the aux is 11.7 When the charger sees the main at 100% I assume it stops charging and possibly leaving the aux battery less than full.

 

[frogjbm]

Cannot imagine RAM wouldn't have designed it whereby the AUX battery wouldn't be connected to the main to receive a charge. If not, then is a very poor design. My 1961 Lincoln Continental is designed this way, I set it up that way, makes total sense to me. Nothing surprises me nowadays, however.

 

[mike12193]

I agree. It would not make sense to charge separately. The way I think it works is the small battery isolates from the main battery when the start/start is engaged. The truck will then use the small battery to run HVAC and other electronics without drawing from the main battery while the engine is not running. I will try to test this week. I would like to get rid of the small battery and run a larger main battery. With RAM it will probably void the warranty.

Probably void th

 

[DBallz]

Hey I just saw a post on the FB forum regarding an Aux battery and swapping it over for an H8 main battery?

First - is the guy that posted that on FB on this forum? Dusty Waterfall?
Second - very interested to understand what you intend to do and your reasoning. I'm assuming because clearly the batteries coming from the factory suck balls.

Thank you

aux batteries suck.... ballz. I'm deep in the Jeeps too and they have doing that since circa 18. They fail every year or every other year and cause a bunch of low voltage and main batter issues. Avoiding all that from the get go plus the OE are having issues with the batteries these trucks come with so that is going straight in the trash. The OE tray will accommodate an H8 battery by simply removing the "7" holder in the tray. There is still room for an aux battery with the H8 if you choose. I really like the idea of more CCA, AH and RC from the larger H8 and eliminating all the current and future issues associated with aux batteries. Something of note the ESS is disabled which is also a bonus to me.

 

[gram10]

so I happened to reach out to the guy on FB, an interesting situation here...

I asked him what he did with the sensor on the auxiliary battery, apparently he didn't have one, but I do.

 

[frogjbm]

so I happened to reach out to the guy on FB, an interesting situation here...

I asked him what he did with the sensor on the auxiliary battery, apparently he didn't have one, but I do.

Isn’t @DBallz Dusty on FB?

That’s odd you have the aux sensor and he doesn’t? Anybody else? I’m starting to think our trucks are really made in China, lol.

 

[gram10]

Isn’t @DBallz Dusty on FB?

That’s odd you have the aux sensor and he doesn’t? Anybody else? I’m starting to think our trucks are really made in China, lol.

anybody else care to check to see what their truck has? also, whether you had a battery issue or not

 

[Banger]

I have the sensor on the negative terminal of my Aux battery (as well as the main battery). At 2400 miles, I have not had any problems with my batteries. Mine was built in November.

 

[RHOfan]

anybody else care to check to see what their truck has? also, whether you had a battery issue or not

I’d luv to check it, but truck at the shop getting computer modules replaced…I should have it back next week (hopefully).

 

[gram10]

For record, I had a battery issue, I think my cause was the key card left in the glove box, but once it drained the batteries there was no coming back, bought two on my own and didn't have any battery related issue since. My seat heater element had to be replaced, I don't think it was relared.

 

[moparfiend]

Had auxiliary battery die, have both sensors. Card is out of truck, keys in Faraday box. I think the hours at tint shop finished off the battery with door open but it was likely just a bad battery.

 

[Remixznflow82]

What size(s) are the factory RHO batteries?
Previous trucks (my TRX included) shipped with an H7 battery. I upgraded mine to an Odyssey H8. Despite what people said, it fit perfectly in the tray and the blanket didn’t need to be replaced. It was a straight swap with no parts/mods required.

This is good news if true for the RHO... Ill look into this.