How many amp-hours?

[maria_bettina]

Hi! I would like your opinions. I have an ATC Panther (pop-up TC) that we are building out. The TC came with a 79 amp-hr battery, which we found to be insufficient. So what does our rig warrant in terms of amp-hrs?

We run ...
-- Dometic electric fridge (0.81 Ah)
-- Fantastic Fan 1.8Ah (but only on a few hours)
-- DIY swamp cooler (unknown, but will be on all night)
-- Recharging electronics, like phone, watch, Kindle, camera battery using an inverter (unknown)
-- 2 indoor LED and one outdoor porch lights
-- And we may want to add some other electronics like a Mr Heater Boss Shower, but not sure exactly what or when, so I want to over-estimate my need at this point.

Before we had solar panels and only had the fridge and lights, we would get down to a 60% charge after a day and charge by driving the truck (alternator).

So we added three 100 watt solar panels, thinking if we were camped under some trees, we might still generate enough to make a dent. And we camp (no hookups) in the winter. And there are some days we get little sunshine.

So with all that, I was thinking a 200Ah deep cycle battery. Too much? What are your thoughts?

[theoldwizard1]

For batteries, I recommend a pair of 6V golf cart batteries. That is about 225 AH @ 12V. These would be cheaper and store more energy than a pair of dual purpose marine/RV batteries. AGM golf cart batteries are available but are $$$ !

The real issue is recharging, especially when shaded or during short days. I think you are going to need more solar panels than you can practically mount on a TC.

This means a generator or a DC-DC battery charger (and running the truck engine for hours) is a must !

Don't forget a good battery monitor like a Victron BMV-700 !

[maria_bettina]

Kayteg1 wrote:

maria_bettina wrote:
( No can do a gennie at this point; we are maxxed out on our payload. And really have nowhere to put it either.

The 1000W inverter generator weight about 25lb and takes less space than the battery.
If you will eliminate 1 battery having it, you have perfect solution.
With TC you can go several ways as technology is flooding us with new gizmos. You will find parallel thread how other member is trying to shave 3/4 tons of batteries from his TC and trailer rig.
Good luck finding the best for you solution.

Thank you!

[Kayteg1]

maria_bettina wrote:
( No can do a gennie at this point; we are maxxed out on our payload. And really have nowhere to put it either.

The 1000W inverter generator weight about 25lb and takes less space than the battery.
If you will eliminate 1 battery having it, you have perfect solution.
With TC you can go several ways as technology is flooding us with new gizmos. You will find parallel thread how other member is trying to shave 3/4 tons of batteries from his TC and trailer rig.
Good luck finding the best for you solution.

[maria_bettina]

cewillis wrote:

Thank you for your input. I think we are going with a 200Ah battery... Now to find the "right" one 🙂

NRALIFR wrote:
Well,I would probably choose two group 27 or 31 AGM’s, and build a box that can double as a step up into the cab-over bed if possible. Those type batteries will fit in a step/box with a rise (height) that will feel normal to you when you are using the step. 6v golf cart batteries could be used if you want, But they are taller than the group 27 and 31 batteries, so if you made a step box for them, it would probably feel unusually tall to you.

Flooded batteries always need a sealed and vented compartment, but AGM’s aren’t as prone to that as wet cells. Technically, I believe all batteries can vent under the right conditions, but it’s pretty rare for AGM’s. They are more expensive than flooded deep cycle batteries, but if you compare quality flooded deep cycle to quality AGM deep cycle, they aren’t that much more.

:):)

Holy moley, Batman! That is a grand idea! We will need to move the cooler, but that placement below the cabover bed was annoying me anyway. having the battery there as a step is a bleeping GREAT idea!!!!!

srschang wrote:
For our use in the Northern U.S., 2-100 ah lithium batteries and 4-100 watt solar panels is a bit more than what we need. Spent a couple months traveling to Alaska and back last year, and didn't need to plug in the entire trip. We didn't have a generator. The batteries didn't charge from the truck either, as I have that wire disconnected. We did plug in a couple nights at campgrounds to run the a/c when it was too hot for us.

Our typical daily power usage:
- watch tv for 2-3 hours at night
- lights
- water pump for showers and stuff
- electric compressor fridge
- listen to music for an hour or so in the morning
- 3 or 4 cups coffee Keurig on the inverter every morning
- wife dries hair on the inverter every morning

Typically the batteries are at 60 - 70% in the morning before the solar starts charging them back up.

Wow! Alaska is on my To-Do list 🙂 Thank you for all the detail about your panels and useage. Helps me make our decision. I think we might disconnect the truck battery too, if we already haven't. Might as well try it out before a huge trip. (Coffee that I don't have to wait for a boil sounds heavenly! Great info - thank you!!)

[srschang]

For our use in the Northern U.S., 2-100 ah lithium batteries and 4-100 watt solar panels is a bit more than what we need. Spent a couple months traveling to Alaska and back last year, and didn't need to plug in the entire trip. We didn't have a generator. The batteries didn't charge from the truck either, as I have that wire disconnected. We did plug in a couple nights at campgrounds to run the a/c when it was too hot for us.

Our typical daily power usage:
- watch tv for 2-3 hours at night
- lights
- water pump for showers and stuff
- electric compressor fridge
- listen to music for an hour or so in the morning
- 3 or 4 cups coffee Keurig on the inverter every morning
- wife dries hair on the inverter every morning

Typically the batteries are at 60 - 70% in the morning before the solar starts charging them back up.

[NRALIFR]

Well,I would probably choose two group 27 or 31 AGM’s, and build a box that can double as a step up into the cab-over bed if possible. Those type batteries will fit in a step/box with a rise (height) that will feel normal to you when you are using the step. 6v golf cart batteries could be used if you want, But they are taller than the group 27 and 31 batteries, so if you made a step box for them, it would probably feel unusually tall to you.

Flooded batteries always need a sealed and vented compartment, but AGM’s aren’t as prone to that as wet cells. Technically, I believe all batteries can vent under the right conditions, but it’s pretty rare for AGM’s. They are more expensive than flooded deep cycle batteries, but if you compare quality flooded deep cycle to quality AGM deep cycle, they aren’t that much more.

:):)

[cewillis]

jimh425 wrote:

I don’t think you can have too many amp hours. You might also want to think about going Li-Ion so you can run the battery down to a lower percentage.

Two good answers here.

[maria_bettina]

Kayteg1 wrote:
Aren't lithium batteries like $1000 a piece?
Personally I don't think you can count on solar panels for several days of camping. YOU NEED BACKUP GENERATOR.
Having generator and I bought 1000W inverter generator for $150 at HD, you can carry less batteries. End of the story.

Say what?! Yea, that's cost prohibitive. 😞 No can do a gennie at this point; we are maxxed out on our payload. And really have nowhere to put it either. But we are definitely trying to figure it out as we have two 2000i Yamaha gennies that we bought for our TC years ago. I was also trying to figure out Air Conditioning, but it seems at 40lbs and taking up a pretty sizeable footprint (we'd need a portable one), that's a no-go as well. Ugh.

NRALIFR wrote:
There’s no such thing as too many amp-hours.

My question would be, what are the dimensions of your battery compartment and go from there, filling it with the most deep cycle amp hours your wallet can stand. Consider all battery types; 6v, 12v, flooded, AGM, and even lithium if you can afford them.

You should ensure you have a battery charger that supports the type of battery you choose as well

:):)

Ok, good idea about the different batteries. We don't have experience with anything but the 12V Deep Cycle, so this is new territory. Our battery compartment isn't a compartment as we bought the shell model, so we are building as we go and as we need to. So size is a consideration but not a deal-breaker. Thank you!

[Lwiddis]

“Personally I don't think you can count on solar panels for several days of camping”

With an adequate solar system ....panels, controller and batteries...and sunlight you are personally wrong. That’s the goal of a solar system, no generator needed except for A/C. You are badmouthing what you don’t understand. 45 days of camping without any use of my generator.

[NRALIFR]

There’s no such thing as too many amp-hours.

My question would be, what are the dimensions of your battery compartment and go from there, filling it with the most deep cycle amp hours your wallet can stand. Consider all battery types; 6v, 12v, flooded, AGM, and even lithium if you can afford them.

You should ensure you have a battery charger that supports the type of battery you choose as well

:):)

[Kayteg1]

Aren't lithium batteries like $1000 a piece?
Personally I don't think you can count on solar panels for several days of camping. YOU NEED BACKUP GENERATOR.
Having generator and I bought 1000W inverter generator for $150 at HD, you can carry less batteries. End of the story.

[maria_bettina]

jimh425 wrote:
I think they mean .8Ah for the circuitry/board of the Dometic frig and it runs on propane.

I don’t think you can have too many amp hours. You might also want to think about going Li-Ion so you can run the battery down to a lower percentage.

We’ve found that we can easily make an entire weekend with our 2 normal batteries in one spot if we run the generator about an hour each day. If we are moving around like at Yellowstone, we almost never have to run the generator. Changing to all LED lights made a huge difference. Also, keep in mind that newer tvs use a lot less power.

It's an electric cooler-type fridge. Dometic CFX series.

Thanks for the reply. Yea, we are barebones. No TV. No LP. No generator (but we have the solar panels). Electric fridge. We got the solar panels so we didn't have to drive to charge the battery. It was a PITA. We camp when we drive a lot and move around (like Yellowstone like you said), and we camp where we don't move the truck for days on end (when we go rock climbing/City of Rocks/or we bring bikes).

I was thinking the same about battery amp-hours. The bigger the better? 🙂

I will look at the Lithium Ion batteries. Haven't really considered it. The battery we have is in the camper, no venting, so that's a consideration too.

[maria_bettina]

Kayteg1 wrote:
You are listing like 100 variables and you want solid answer?
I hope not?
I camp with single battery just fine and I make HUGE cup of coffee every morning on inverter power.
But then I usually drive the same day, or start generator for AC operation.
In your list I see electric refrigerator. Would you camp in area with triple digit temperature, or with fridge side facing south the poor thing will run 100% of the time. For that alone you need 200AH battery bank and probably bigger solar than you already have + backup generator for cloudy days.
BTW is the fridge really running on 0.8 amp?

re. the fridge, that's what the specs say. We were using about 32 amps in a day with just fridge and fan, and I think I remember not using the fan too much. We camp in 80-90 degree weather at times, and the fridge is running when we are driving through 100+ degree heat too. I am sure the specs say 0.8 Ah at 70-degrees, which is not realistic.

Yea, we are familiar with swamp coolers and in what environments they will work and not work well. Thanks though.

So yes, I posted to get ideas. And I posted all the variables because that's real life. Maybe someone has a similar setup. Who knows. Maybe someone has gone through this.

[jimh406]

I think they mean .8Ah for the circuitry/board of the Dometic frig and it runs on propane.

I don’t think you can have too many amp hours. You might also want to think about going Li-Ion so you can run the battery down to a lower percentage.

We’ve found that we can easily make an entire weekend with our 2 normal batteries in one spot if we run the generator about an hour each day. If we are moving around like at Yellowstone, we almost never have to run the generator. Changing to all LED lights made a huge difference. Also, keep in mind that newer tvs use a lot less power.

[Kayteg1]

You are listing like 100 variables and you want solid answer?
I hope not?
I camp with single battery just fine and I make HUGE cup of coffee every morning on inverter power.
But then I usually drive the same day, or start generator for AC operation.
In your list I see electric refrigerator. Would you camp in area with triple digit temperature, or with fridge side facing south the poor thing will run 100% of the time. For that alone you need 200AH battery bank and probably bigger solar than you already have + backup generator for cloudy days.
BTW is the fridge really running on 0.8 amp?
Also swamp cooler will not be efficient when you camp in higher humidity areas, aka Folsom lake.