Best Battery for me?

[waterguy1111]

Hey there. I am still working on the Electrical logistics for my teardrop. Still in the planning stages, actually. My question is if I want to stick with a 12 volt battery for my teardrop, What is the best battery for me? I plan on a total of 40 to 45 amp hours per day (my estimate) I plan on putting my battery in a box on the tongue of the TD. (along with a charger). No more than 2 days without a charger.

Am I overthinking all this?

ken

[lfhoward]

It sounds like you might want to invest in 2 batteries or get a solar panel if you’re going to be out for 2 days and use 90 Amp Hours of juice during that time. Although you can find nice 100AH batteries, you shouldn’t drain them down to more than 50% of their capacity (preferably not even that far) if you want them to last. Thus, you’d need 200 AH of storage if you’re needing to use 90 AH in between charges.

Can you make us a list of what devices, how many amps they draw, and how long you expect to run them? Perhaps you don’t need 40-45 amp hours per day?

[tony.latham]

I too am wondering what you are going to use that requires so many amps.

We use about 8 amps per night and most of that is from my CPAP.



Tony

[waterguy1111]

I guess the big user is the Exhaust Fan. It supposedly draws 4.5 amps. I was thinking it would run 7 hours Max? Then the LED reading lights and a couple USB phone chargers
.

Ken

Should I consider solar as well?

[waterguy1111]

I guess the big user is the Exhaust Fan. It supposedly draws 4.5 amps. I was thinking it would run 7 hours Max? Then the LED reading lights and a couple USB phone chargers
.

Ken

Should I consider solar as well?

My LED lights are probably not going to be on that long I would think. Maybe 4 lights at 300mA for an hour or so tops.

[MickinOz]

Should I consider solar as well?

Certainly should.
The exhaust fan would draw 4.5A on high, I'm guessing?
Probably draw less on low speed?
But let's say you do use around 40 AH per day - then you need at least 4 times that in battery capacity to keep depth of discharge to around 25%.
And that is if you can recharge it each day.
So yes definitely need solar.
What I reckon you need is to get hold of your fan, if you haven't already done so, and test it at the various speeds on a well charged battery.
I read things that suggest the fantastic fans move way more air than necessary on full speed, and make a bit too much noise on full throttle. There are even threads asking how to slow them down.
Done right, slowing a motor down uses less amps.
So, test the fan on the different speeds. You might find the air flow you are happy with uses far less amps. Which has design influences for your system.
Don't underestimate the USB thing some of those outlets are 3 amp.

[waterguy1111]

Thanks Everyone for the time to answer my questions! I will definitely look into solar and have the Fan amps checked out.


Ken

[S. Heisley]

I guess the big user is the Exhaust Fan. It supposedly draws 4.5 amps. I was thinking it would run 7 hours Max? Then the LED reading lights and a couple USB phone chargers
.

Ken

Should I consider solar as well?

Only LED lights and a fan? I don't know for certain, but maybe you are overestimating your usage? I can't tell you how much your phones should take (I turn mine off for uninterrupted sleep.) but each of my LED lights takes .16 amp per hour. That's point one six, not a typo. Also, check that exhaust fan figure. 4.5 amps might be the max it takes on high. It would probably be too noisy at that speed for long and also unnecessary to run it on high very much. If you can run it on medium or low, you might save a lot of amps. The 12 volt plug-in auto/truck oscillating fan that I have only uses 1 amp an hour. Assuming you aren't using air conditioning, I would think that a regular fan would give you more over-all comfort than an exhaust fan. (My dogs love it.) In addition, check your battery weight and trailer weight balance. The more amps the battery has, the more it weighs and the more you may have to counter-balance. If you can't get your amp usage down a bit, then yes, you may want to consider solar.

But then, I tend to be very conservative with things. I turn off lights unless I'm in the direct area and I even minimize my use of water and propane. Five pounds of propane (not 20) will last me at least 2 years. Those little use and toss propane cylinders? I can get one of those to last 5 days while feeding a family of 7 two hot meals a day with sandwiches for lunch.

...Just my thoughts.

[bdosborn]

The fans draw more than you would guess. Cosmo just did a video on them and he shows the current draw.

The Endless Breeze uses the same motor as the Fantastic Fan.

Bruce

[Tom&Shelly]

I measured our MaxxFan on each of it's ten settings:

0.05 A
0.10 - 0.15 A
0.20 - 0.22 A
0.30 - 0.40 A
0.5 A
0.7 A
1.0 A
1.35 A
1.80 A
2.65 A

Quite a range!

Tom

[tony.latham]

We’ve spent twenty nights in Idaho/Montana and have used our Fantastic fan for about thirty minutes. And it’s always on low. I can’t imagine needing it on high for more than a few minutes.

Perhaps you’re in the Deep South?

I slowed my fan down with a resistor and it draws 1.5 amps. Maxxair fans pull about half.

Tony

[waterguy1111]

I've bought the Maxxfan Too! That is quite the range! A TON less than the 4.5 amps I was told!''



Ken

[Graniterich]

I vote solar, if you want it you have the option to go forever. Doesn't have to be huge or expensive

Sent from my KFKAWI using Tapatalk

[RJ Howell]

You usage is more than double mine in the old Commercial camper! For fans we use (still use) the USB personal fans and only used the house (vent fan) for minutes to cool down the camper. We could get our usage down to 12amps daily and still felt it was a lot. Worked that down even more by using two lithium power packs I made up with 18650 batteries. Those ran the fans all night and the reading lights for a few nights easy and recharged in the truck as we drove.

I setup dual 6v batteries that were 230ah each. That gave me a max of 115ah of usable power. I never did get below 35-40ah used before recharging which made for easy short cycles on the battery (good for longer life). The first 40 day run I brought my 130w solar panel with me and found that I really didn't deploy it much due to my DC/DC was keeping up nicely as we drove. This is many due to usage on the battery and that we stayed in one spot no longer than 3 days. The DC/DC (which I now exclusively use) was recharging in just about 1.5hrs of drive time.

Now I'm down to a 60ah LiFePo4 and recharge only by the DC/DC charger. I'm still at about 12-18amps daily, yet now my main draw is the refrigerator, most times my only draw since we still use those lithium power packs. We still only stay put for a max of 3 days so the system works for us.

Just what I now do, did and how we now roll. Hope any of this helps!

[waterguy1111]

So Many great ideas! I love this Forum!!! So insightful!!


Ken