Amp hours

[Twistedlarch]

I'm trying to determine whether my current solar system is adequate or if I need to add more panels/batteries.

Currently I have 2 6 volt lead acid batteries.
I have 300 watts of panels
40 amp controller

I'm curious as to how many Amp hours my trailer uses.

Small 3 way fridge running on LP
CM detector
Stereo on standby mode
Water pump

I usually try to use battery powered lights at night.

The kids also watch a movie to unwind at night, the TV and DVD player run on a separate small battery hooked to an inverter. Small battery will be charged during the day from the panels.

We keep water use at a minimum.

I also have two dual USB charging ports.

Heat is set at 60. Night time outside temps can dip down into the high 30's in Spring and late Summer where we usually camp

Our usual camping area is at 4,500-5,000+ altitude with pretty intense sun in the afternoon.


Thanks
Brian

[deltabravo]

Camper8251 wrote:
Nobody will be able to answer this for you. Way to many variables.
Need a meter or something else..

YEP! You need an amphour meter

I run a Victron BMV712

[dieseltruckdriv]

Twistedlarch wrote:

wopachop wrote:
Been meaning to disconnect my solar and cycle my batteries. Will get some rough numbers for ya tonight or tomorrow.

So no generator right? Like others said your only real variable will be how much heater you can run each night. One of the portable propane heaters might really come in handy. Or a small genny if you can make noise at night/early morning.

I do have a little Yamaha Genny for back up.


Brian

I have a pair of Honda 2000s as backup power. We also have a pair of group 31 AGMs, and 420 watts of solar.
We were out last week, and on one day the clouds were so thick that we didn't get any charging all day. We went into the evening at a negative 28 amp hours. The next day was partly cloudy (-58 amp hours according to my Victron BM-702) and by evening when we like to watch tv (using a pure sine wave inverter) we were fully charged.

My normal draw is 1.5 to 1.75 amps. This is with the fridge on, and ready to do anything we want, but us not using anything.
Conventional wisdom here says to have one watt solar to one AH of battery. That wasn't enough for us. After 9 nights, we never needed the generator. I told my DW that I want to add another 400 watts of solar, and she agreed after that experience. We did OK last summer with 300 watts of solar, but we didn't use the furnace, this time we used it normally. We also set it at 60 overnight.

All of that being said, we use everything we want to, lights, tv whatever. We don't waste power, but don't scrimp to conserve it either. I actually did a power audit, but in the end just went by trial and add more solar then trial again. 🙂

[teejaywhy]

Twistedlarch wrote:
I'm trying to determine whether my current solar system is adequate or if I need to add more panels/batteries.

Currently I have 2 6 volt lead acid batteries.
I have 300 watts of panels
40 amp controller

I'm curious as to how many Amp hours my trailer uses.

Small 3 way fridge running on LP
CM detector
Stereo on standby mode
Water pump

I usually try to use battery powered lights at night.

The kids also watch a movie to unwind at night, the TV and DVD player run on a separate small battery hooked to an inverter. Small battery will be charged during the day from the panels.

We keep water use at a minimum.

I also have two dual USB charging ports.

Heat is set at 60. Night time outside temps can dip down into the high 30's in Spring and late Summer where we usually camp

Our usual camping area is at 4,500-5,000+ altitude with pretty intense sun in the afternoon.


Thanks
Brian

You have a pretty nice setup. As others have mentioned, the furnace will be your biggest user. The other stuff (TV, DVD, LED lighting, chargers) are minimal draws and can easily be ran from your main batteries without need to have separate batteries.

Complete your setup by installing one of these:
https://www.victronenergy.com/battery-monitors/bmv-712-smart

[01tundra]

The Victron BMV current readings for our particular trailer -

[Huntindog]

Twistedlarch wrote:

wopachop wrote:
I have the same clamp meter linked on page 1. This is the amp draw using 2 fully charged 6v's. I think theyre the newer version of your batts. The costco interstate but only 210ah.

With the trailer turned on it pulled 0.18a just resting. That small 0.2a draw is included with the numbers below.

Fridge: 0.97a
Water Pump: 4.87a
TV and Stereo: 3.7a
Furnace: 5.25a
Bunch of white LEDs: 3.40a
Color Changing LEDs: 1.3a

Thanks! 🙂

When looking at these numbers, keep in mind that the Waterpump draw, though the second highest, actually consumes very little battery power.
This is because it is limited by the water tank volume. A 40 gallon tank, at 3GPM will run dry in a little over 13 minutes! The furnace by comparison can run for hours overnite.
Same goes for just about all of the other loads.

[Twistedlarch]

wopachop wrote:
I have the same clamp meter linked on page 1. This is the amp draw using 2 fully charged 6v's. I think theyre the newer version of your batts. The costco interstate but only 210ah.

With the trailer turned on it pulled 0.18a just resting. That small 0.2a draw is included with the numbers below.

Fridge: 0.97a
Water Pump: 4.87a
TV and Stereo: 3.7a
Furnace: 5.25a
Bunch of white LEDs: 3.40a
Color Changing LEDs: 1.3a

Thanks! 🙂

[Twistedlarch]

Lwiddis wrote:
All this solar/battery math and surveying should have been done prior to you mounting any panels as you posted on March 27.

Never said I mounted anything yet.

[wopachop]

Gas valve Tuna? I can pop my cover and test it. I noticed the fridge pulled 0.7a and then bumped to 0.976a. Seemed to hold that .97a number for a couple minutes. I dont know if the fridge fan turned on. Its not warm today.

[RickLight]

Something to recognize:

Measuring voltage while something else is connected is highly deceptive. The higher the other load, the further off you will be. That includes your gas/smoke detectors.

[pianotuna]

wopachop,

Measure the gas valve on the fridge?

[wopachop]

I have the same clamp meter linked on page 1. This is the amp draw using 2 fully charged 6v's. I think theyre the newer version of your batts. The costco interstate but only 210ah.

With the trailer turned on it pulled 0.18a just resting. That small 0.2a draw is included with the numbers below.

Fridge: 0.97a
Water Pump: 4.87a
TV and Stereo: 3.7a
Furnace: 5.25a
Bunch of white LEDs: 3.40a
Color Changing LEDs: 1.3a

[Twistedlarch]

wopachop wrote:
Been meaning to disconnect my solar and cycle my batteries. Will get some rough numbers for ya tonight or tomorrow.

So no generator right? Like others said your only real variable will be how much heater you can run each night. One of the portable propane heaters might really come in handy. Or a small genny if you can make noise at night/early morning.

I do have a little Yamaha Genny for back up.


Brian

[wopachop]

Been meaning to disconnect my solar and cycle my batteries. Will get some rough numbers for ya tonight or tomorrow.

So no generator right? Like others said your only real variable will be how much heater you can run each night. One of the portable propane heaters might really come in handy. Or a small genny if you can make noise at night/early morning.

[Twistedlarch]

pianotuna wrote:
Those are good results--but did not include running the furnace. It is by far the most 'hungry' device.

I'd double the battery bank and add 150 watts of solar.

I would like to increase my bank size but my only issue is, my single axle trailer only has a 508 lb payload. I think adding 120lbs of more batteries would put me over. I guess I could throw them in the back of the truck though.

Brian