More battery questions

[WV Camper]

I have read through the other threads and there is a lot of good information. Even so, I am still not sure what to do.

Here is my scenario:
Jayco eagle 5th wheel with space for 4 batteries
on board Onan 5500 generator
would like to be able to run for 24 hours between charging - will run the 13cf gas/electric fridge, lights, CPAP, water pump. (do not have an inverter so no 120V on batteries, will start generator if needed).
I don't want to spend $1000
our boon docking would be limited to 3 days at a national forest type campground or dispersed area.

My questions are:
what batteries would be adequate-
How long each day does the generator have to run to charge it/them

Thanks,

[RogerR]

The fridge and water pump will not use much if the fridge is on propane. The cpap machine requires much more if you use the water heater humidity function. Less but quite a bit based on models.

Just a guess assuming you aren't going to leave every light on, watch TV and play on your computer and run the furnace ( which is a big power hog) that a single 100 amp lithium battery would work. Not sure of charge time as I don't have a generator. I get 1 night from a simple group 27 with light furnace use, mostly covers and no tv or cpap.

[deepsea5]

Originally Posted by WV Camper

I have read through the other threads and there is a lot of good information. Even so, I am still not sure what to do.

Here is my scenario:
Jayco eagle 5th wheel with space for 4 batteries
on board Onan 5500 generator
would like to be able to run for 24 hours between charging - will run the 13cf gas/electric fridge, lights, CPAP, water pump. (do not have an inverter so no 120V on batteries, will start generator if needed).
I don't want to spend $1000
our boon docking would be limited to 3 days at a national forest type campground or dispersed area.

My questions are:
what batteries would be adequate-
How long each day does the generator have to run to charge it/them

Thanks,

FYI: a lot of the CPAP manufacturers offer a 12 Volt power cord for their machines. Having one would save from needing an inverter to run just the CPAP.

[Vicr]

Asking about "what's the best battery" is like asking "what's the best motor oil". In a couple days you'll have a hundred different answers. You say you have room for 4 batteries but you don't tell us what group size. What ever you get make sure they are True Deep Cycle battery. The "best type" of battery is a group GC (as in Golf Cart). Most of the time you are better off with 6v GC batteries wired series (2) sets/ parallel. I'm sure someone with more time on their hands will explain what I'm saying in more detail.

[WV Camper]

I did not ask "what's the best battery" I asked what would be adequate for the scenario I laid out and what the charging times would be.

I am aware of using golf cart batteries and I expect they would serve my needs but I don't know how long they take to recharge.

It is my understanding the AGM batteries take less time to recharge so maybe one of them would be adequate but again, I don't know what the charge time is.

Lithium, for all the praise they get, are too expensive for my limited boondocking needs.

Hopefully there is someone who can help me with these answers so I can make a decision.

[JimD]

You may be able to get by with a single group 27 battery if all you need is 24 hours. Adding some solar would reduce the required recharge times. Another option is to get an inexpensive inverter/generator to top off the battery before night. Much cheaper to run and will save the big generator for things it will need to power. Quieter too!

[16WhiteColly]

If you decide on AGM batteries, make sure that what you will be charging them with is comparable for charging use with AGM batteries. You could probably buy two lead/acid batteries for slightly more than one AGM.

[WV Camper]

Originally Posted by 16WhiteColly

If you decide on AGM batteries, make sure that what you will be charging them with is comparable for charging use with AGM batteries. You could probably buy two lead/acid batteries for slightly more than one AGM.

I read the information on the progressive dynamics converter in our 5th wheel and it says it is compatible with AGM and lithium (by setting a switch on the board). It is my understanding that AGM will charge faster than standard batteries? I recognize that the onboard converter/charger is not the best battery charger money can buy. I am trying to find the best real world compromise using the equipment I have.

This battery will also need to be able to start the generator and the lithium ads say they are not for starting engines.

[bluztoo]

I did some boondocking recently in a parking lot (long story and involves in-laws) and I could go two days on two 100 AGM batteries. I was there for the week and could not use the generator based on location so I ended up driving the RV a couple of times to juice the batteries. I was not happy with that and have since upgraded to lithium so that I can go at least four days based on my consumption. Adding in solar panels should give me more time but that's about some, lots, or no sunshine. Can't rely on it. But it's based on your needs. AGM batteries remain the all around champs and do deliver cranking power in abundance. Because they're lead you can only "consume" half the batteries power compared to eighty percent of lithium. So you'd get a boost even if you put in the same size battery(s) you have now. I don't think anyone "needs" lithium unless they really know they're going to be off grid for a while. Some of my favorite parks don't have electric so my mix of lithium and generators (which are loud) works out. In terms of cost - lithium has dropped. If it weren't for shipping problems I would expect it to drop more. Some of the no-name batteries on Amazon are cost effective if they do last ten years. Some of them suggest warranties and may have them. But those batteries are cheap in cost but maybe design too. I've said too much. Lithium is cost effective over the long cycle now. But it still doesn't mean it's the best technology based on a person's needs.

[WV Camper]

Is there an advantage to using two, let's say 100 ah batteries over 1 200 ah battery?

[RogerR]

There are some I can think of:
Picking up a heavy battery vs. 2 lighter ones.
If a cell goes bad you still have one good battery.
2 smaller batteries may fit better in your space

vs.
a single 200 may be cheaper than 2 - 100's
you don't need jumper cables to a second battery

[royphillips]

I’m not sure how long you would have to charge the battery to get a full charge likely a couple hours but I do know that you want deep cycle batteries because they are made to be fully discharged and the charged again without hurting them. AGM batteries are best used for a starter battery and not for the coach

[billcf7]

A typical flooded or AGM lead acid battery takes about 5-6 hours to fully charge from 50% A lithium battery with the same AMP/HRS will charge in 2-3 hours from 80% discharged. Lithium batteries can now be purchased for about the same price as higher end AGM if you shop around.

[videoarizona]

I would recommend 2 GC 6volt batteries. Your CPAP will be a large daily draw and GC lead acids are the ONLY "deep cycle" lead acids that can handle discharge below 50% without damage. Think about that...golf carts do abuse batteries daily!

Yes, they are heavy. Yes they will charge up slightly faster than a regular lead acid. And you can get 2 100amp/hr GC2 batts for about $100 each. That gives you a good solid 100 amps to play with.

I'm on year 3 with my GC set up. I run CPAP. Charges up in about 5hours. But I have the problem of having a long run with the stock 12volt battery cable being under sized. With your generator on board, I bet you can charge up in less than 4 hours.