Overnight battery requirements

[Jay & Bobbie]

I'm considering a Renogy AGM 12v 200Ah/20HR to replace the current single Diehard 27HM. Will be going in a 2018 345rl with an electric only residential refrigerator. The purpose for the upgrade is to operate the refrigerator, water pump and few lights overnight when staying at a cracker barrel or other freebee without shore power or permit generator. We do not have any solar.
The question is: Is this a plug and play replacement? Other suggestions welcome.
I believe this battery does not need to be in the vented battery box also.
I know it is big and heavy, but the cost is way better than lithium and we are not planning to boondock for extended days (just overnight when traveling).

[RichR]

I would think you would need at least two batteries to work all that.

[AZ Traveler]

Jay,

This thread will give you some good info on how much juice your reefer uses. https://www.montanaowners.com/forums...hlight=lithium

I concur with Rich, you are likely better off with two. They will last longer and give you more reserve. A single battery is likely to get drawn down below 50% fairly often shortening its life.

[Todd & Mary]

Remember 200ah AGM will only give you 100ah at 50% discharge. You will most likely need at least 2 of them for this.

[Foldbak]

You're absolutely going to need 2 deep cycle batteries. I assume you already have a built in inverter? If so you won't be running the fridge for long periods of time. Maybe 5 hours (possibly more) between recharging your batteries to 100%. IMO you need to consider a solar upgrade. Most rigs with residential fridg's rely on shore power and use the inverted power for traveling. Residential fridge's are not a good option for dry camping.

[Jay & Bobbie]

Thanks all, I think for now, staying at parks with power is the best way for us when long distance traveling.

[rames14]

Jay and Bobbie, everyone has different situations. Out west, we have an abundance of boondocking opportunities and we also use Harvest Host while traveling. Also, campgrounds are booking sooner and many of us find it easier to stop at alternative camping locations. It’s a trade off on costs. Safe travels.

[Jay & Bobbie]

I am still looking for ways to spend the night without shore power.
I agree that I likely need 200Ah of usable reserve to power our rig for a comfortable night while traveling. Yes, the rig is equipped with a 1000w pure sine wave inverter for the refrigerator.
A couple questions that I have not been able to resolve.
A: 6v battery bank ( yes a lot of weight) vs 12 v
B: Standard lead acid vs AGM
C: Will the TT charge the batteries while traveling the next day, assuming approximately 4 to 5hrs.
D: Will I need to change any wiring in the rig to accommodate the increase in reserve capacity. I think I know the answer, but would like to get others advice.

[AZ Traveler]

Jay and Bobbie,

There are several options to pick from depending on your planned use and how much you want to spend.

If you plan to stay with FLA or AGM batteries 6 volt is an easy conversion. You typically get more AH from the golf cart batteries. Or you could go with two 12 v batteries similar to what you have based on the fact you very seldom overnight without power. AGM are more expensive than FLA but have the advantage of not needing to check or add water.

Another option is buying a 2000 watt genny. It could come in handy if the power in the campground fails or you decide to venture into more boondocking.

Once your reefer including all that is in it is cold you could even shut it off for 6-8 hours without losing any food as long as you don't open it a lot.

Lithium is an option that could be a pay only once for 10-15 years of use - if you go that way I would recommend heated batteries if you plan to camp in the cold. A total of 200 AH would put you in pretty good stead as about 90% is usable.

Charging from your tow vehicle will not help much for recharging the batteries going down the road but should give you enough power to keep the reefer going.

[Jay & Bobbie]

Thanks for the info and expertise.
I do like the lower maintenance of the AGM batteries and that they don't require a ventilated box.
I already have a 4000w generator that I plan to carry when traveling. It will also run on of the the ac units in a pinch.
I did forget to mention that the refrigerator has a eco mode. I tested it with the current single battery and the battery was down to 12v in 5 hours. That was with no lights or water pump coming on.
I'm not sure if our rig has a charger that will switch to charge lithium. How do I find out?

[twindman]

I think the biggest draws are: A/C, then furnace or frig. If you don't need these things, then I think you can go all night with standard battery/ies. I have camped in Big Horns where temp was around 40 or below. My furnace draws down my 2 6V overnight by 7 or 8 am if I start it by 8 pm. Actually pretty dead at 5 am when starting at 7 or 8 pm (ask me how I know).

[DebNJim B]

I have the Renogy 200 Ahr in my rig. It's big and heavy and I had to use a portable engine hoist to get it in but the change came out nice. AGM allowed me to eliminate the battery box.
I too only wanted overnight power and this battery does the job just fine. My experience indicates it will go between 24 and 40 hours just running lights, water pump and refer.

[Jay & Bobbie]

Thanks, all good information.

[Jamric]

Originally Posted by DebNJim B

I have the Renogy 200 Ahr in my rig. It's big and heavy and I had to use a portable engine hoist to get it in but the change came out nice. AGM allowed me to eliminate the battery box.
I too only wanted overnight power and this battery does the job just fine. My experience indicates it will go between 24 and 40 hours just running lights, water pump and refer.

Is it a residential Refridgerator?

[DebNJim B]

Yes , the Samsung 18 footer.

[Jay & Bobbie]

Jim, we probably have identical set up. I feel confident that Renogy will serve my needs well.
Thanks

[rames14]

Just a quick comment. Many of the national parks significantly limit generator usage. If you don’t boondock, it’s not an issue. At Teklanika CG in Denali, we can only run generators for 4 or 5 hours (been awhile since I got the hours). That is where lithium really shines, being able to fast charge. Best of luck.

[Daryles]

I installed a DC-DC charger. Does a great job charging your batteries while driving and you can use it as a back up to solar or a generator.

https://www.montanaowners.com/forums...hlight=charger

[rames14]

Daryl, us also, but you really need lithium to get full advantage. And many of the National Parks limit the hours for generators - running a vehicle in place of a generator is not exactly following the spirit of the law. Of course many don’t boondock. We do extensively, so it is critical to us. The other advantage with our solar and lithium, we are traveling with a single Honda 2000. It all depends what you are trying to accomplish.

[Daryles]

Originally Posted by Jay & Bobbie

I'm not sure if our rig has a charger that will switch to charge lithium. How do I find out?

To check your converter to see if it's lithium ready,
Look up your model number (white sticker inside the door of your circuit breaker panel) on Progressive Dynamics webpage

https://www.progressivedyn.com/suppo...ooting-guides/

Or take the cover off and look for a tiny LA/Li switch.
Most likely yours is not lithium ready. No biggie. Mine isn't either, but I put lithium batteries in 4 years ago. Before we go boondocking I use the mode button to kick the Charge Wizard into boost mode to charge the lithium batteries almost all the way up.
Progressive Dynamics Charge Wizzard:
https://www.progressivedyn.com/wp-co...rd-Pendant.pdf

Since then I've added solar panels and a DC-DC charger.