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?

[Camper_Jeff___K]

Just to keep it simple. Over the years with two of us and all our toys, laptops running till midnight and furnace till morning. We currently have 210 AH of AGM and 240 watts solar which gets me by for half of the needs I have. To do it right, we need a minimum of 300 AH AGM and 400 watts solar, I also connected 4AWG wire via a constant duty solenoid for no voltage drop, from the alternator to the TC batteries. I also have an AGM vehicle battery so all batteries have similar load, charge characteristics. We do not have a generator. The solar and truck engine alternator handle the charging nicely.

[pianotuna]

If a vrla has an internal short, it may produce a good quantity of hydrogen sulfide gas. This is a poison. Vent the bank--it's not rocket science to do this.

[jaycocreek]

Battery Technology for Data Centers and Network Rooms:
Ventilation of Lead-Acid Batteries

Executive summary:

Lead-acid batteries are the most widely used method
of energy reserve. Ventilation systems must address
health and safety as well as performance of the battery
and other equipment in a room. Valve regulated lead
acid (VRLA) batteries and modular battery cartridges
(MBC) do not require special battery rooms and are
suitable for use in an office environment. Air changes
designed for human occupancy normally exceed the
requirements for VRLA and MBC ventilation.

Vented(flooded) batteries, which release hydrogen gas
continuously, require a dedicated battery room with
ventilation separate from the rest of the building. This
paper summarizes some of the factors and U.S. codes
to consider when selecting and sizing a ventilation
system for a facility in which stationary batteries are
installed.

[pianotuna]

VRLA batteries do fail. Often this included them releasing internal pressure by venting. Put them in a sealed box, and vent to the outside.

I would not have LI batteries in my living area.

[NRALIFR]

It is entirely possible (for me anyway, knowing my own skill set) to build a battery compartment in the location I suggested, and have it be both sealed and vented to the outside air.

That’s the way I would do it just because I don’t like trusting things that SHOULD not happen. I tend to prefer WILL nots.

:):)

[jaycocreek]

FLA and AGM batteries will vent and for safety reasons need to be outside, not inside. If you want batteries inside you need to use LifePo4 batteries.

Is that will vent or can vent?

I am no battery expert by far but I did read alot before I bought my VLRA AGM battery..They use VLRA batteries on Nuclear submarines/on wheel chairs and floor scrubber machines,all used and stored inside..

My understanding is,they can vent if misused?..That was more of a question than statement..

VRLA stands for “valve-regulated lead-acid.” It’s a general term for a lead-acid battery in which there is a safety valve to control the release of gas from the battery. Under normal circumstances, the valve is closed, which allows the hydrogen and oxygen produced during charging to recombine inside the battery, preventing loss of electrolyte. If the battery is overcharged or charged too fast, the valve can open to allow some gas to escape.

And this..

VRLA batteries are used extensively in power wheelchairs, as the extremely low gas and acid output makes them much safer for indoor use. VRLA batteries are also used in the uninterruptible power supply (UPS) as a back up when the electrical power goes off.

VRLA batteries are also the standard power source in sailplanes, due to their ability to withstand a variety of flight attitudes and a relatively large ambient temperature range with no adverse effects. However, charging regimes must be adapted with varying temperature.[16]

VRLA batteries are used in the US Nuclear Submarine fleet, due to their power density, elimination of gassing, reduced maintenance, and enhanced safety.[17]

It seems if a person used them inside the RV by a well ventilated area,they would work just fine under normal circumstances..I have seen many threads on using an AGM battery inside an RV,some right here on this forum..There are a ton pf people that do it and others say not to kinda like the Catalytic heater debate..

[Kayteg1]

AGM batteries are build with no vent.
That said, my 1998 Mercedes sedan had flooded battery installed under rear seat.
There are flooded batteries who have venting tube, who in about 1/4" size need a hole in the floor for proper venting outside.
That in fact is what I use in my Sprinter van for house battery.
Bought 100Ah battery for $105 and 96 months warranty. Hard to beat the value.

[Freep]

maria_bettina wrote:

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!!!!!

FLA and AGM batteries will vent and for safety reasons need to be outside, not inside. If you want batteries inside you need to use LifePo4 batteries.

[Freep]

Kayteg1 wrote:
Aren't lithium batteries like $1000 a piece?

Much less than that if you build them yourself.

[NRALIFR]

A Honda or Yamaha 1000 generator is pretty light, and easy to cary and stow. It’s also more than enough to run a 45-50 amp multi-stage battery charger. I have a built in Generac 3600 LP generator In my TC that I rarely ever use, and a Yamaha 1000 that I use all the time (no solar).

I also have a Redarc DC-DC charger that allows the truck alternator to supply up to 25 amps of DC power to the camper whenever the engine is running. That’s more than enough to keep the camper battery fully charged, and run the fridge in DC mode while driving.

:):)

[maria_bettina]

theoldwizard1 wrote:
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 !

Yep, already got a Renogy Rover 20 Amp 12V/24V MPPT Common Positive Solar Charge Controller. :C

jaycocreek wrote:
Just a side note on your Dometic CFX cooler..I have seen countless reviews of all the portable compressor refer's seeing just how long they will run on battery power..

As an example,the CFX-50 will run about 60 hours on the 500 WH Jackery power station which is equal to a good group 24 battery at 50%..84 amp hours to watt hours is 1008wh but at 50%,which is he lowest you want to go with a 12V battery,it is 504wh or the same as a power station with 500 watt hours..

So in 60 hours of running the refer for the CFX refer alone,you would be out of juice or at 50% on that group 24 battery in alittle over two days...

I run my Engel refer on a stand alone battery with a volt readout and all the other stuff on other batteries...The refer alone draws more than people realize,depending on which model you get/temp and how often it is opened...Dometic public numbers are alittle deceiving compared to actual use..

Yea, unfortunately, we are poster children for the "Believing the low power draw" on the CFX-50. 35-40% discharge after a day on average on a 79 Ah battery, and I unplug the fridge at night. So it's using 30-ish Ah in a day (and this is not in 100-degree heat either!). We have been camping numerous times for up to 3-weeks at a time in the last year with the fridge and it's pretty consistent.

pianotuna wrote:
More amp-hours is better so long as there is a way to fully recharge the bank assuming lead acid jars.

Yep, we have been trying to figure out a way to carry a generator. I was thinking of removing the connection between the alternator and the TC battery, but now I am not so sure (at least til we have a generator).

[pianotuna]

More amp-hours is better so long as there is a way to fully recharge the bank assuming lead acid jars.

[jaycocreek]

Just a side note on your Dometic CFX cooler..I have seen countless reviews of all the portable compressor refer's seeing just how long they will run on battery power..

As an example,the CFX-50 will run about 60 hours on the 500 WH Jackery power station which is equal to a good group 24 battery at 50%..84 amp hours to watt hours is 1008wh but at 50%,which is he lowest you want to go with a 12V battery,it is 504wh or the same as a power station with 500 watt hours..

So in 60 hours of running the refer for the CFX refer alone,you would be out of juice or at 50% on that group 24 battery in alittle over two days...

I run my Engel refer on a stand alone battery with a volt readout and all the other stuff on other batteries...The refer alone draws more than people realize,depending on which model you get/temp and how often it is opened...Dometic public numbers are alittle deceiving compared to actual use..

[jimh406]

We can’t see yours though. What model did you buy?

[Kayteg1]

theoldwizard1 wrote:


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

Looks like I saved 170 bucks buying this one for 4 bucks.
I think mine looks better.