Water pump amp draw?

[marquette]

I am researching installing solar on my 1987 Scotty retro camper. It is currently put away and winterized and will be for at least another month. I converted it to LED lights last year. It has no micro wave, coffee maker, etc. so the only real draw is the water pump. So if anyone knows what the water pump draws I can try to figure out my daily battery usage to determine how much solar I need and if it is practical for boon docking with the trailer. It has a 12 gal water tank and we can go 3 days on a tank of water so I assume the water pump will pump 4 gallons a day.

[Almot]

marquette wrote:
It has no micro wave, coffee maker, etc. so the only real draw is the water pump. So if anyone knows what the water pump draws I can try to figure out my daily battery usage to determine how much solar I need

WHERE, and WHEN?

For boondocking in winter in Az or Mexico you need 200-400W solar and 200-300 AH battery bank, with your stated loads (including fridge 10-12 Ah a day that you probably forgot to mention).

In some places of PNW or Canadian Pacific you might need 1000 W solar IN SUMMER to just get by, when you hole up in some rainforest and - guess what - it lives up to its name, raining for weeks.

With 12 gal tank limiting your boondocking to mere 3 days this is what will limit your stay, not a water pump draw.

Just wondered how much a fridge average draw is.

Then measure it. Like SMK said, it's roughly 0.5A@12V when cycling. 18 AH a day, to err on the safe/high side.

[marquette]

I already have the fridge. Just wondered how much a fridge average draw is.
Until I can get my trailer un-covered from winter storage I can't tell how much roof space I have available. It's only 14.5 ft long so there is limited roof space.
Sorry for the delay in answering but syruping season has started in Minnesota so time is limited. We got a small break today because of the weather yesterday.

[RJsfishin]

Forget the water pump and all that chart stuff. Its really very simple.
Sounds like 100 watts would do it.
That means, throw a couple hundred watts on the roof, along w/ a good 30 amp controller, and see how it goes. If it don't go, add another 100 watts.
Or, put 300 watts up there right away, and forget it.

[red31]

4-5+ kWh/m2/day on a flat surface during an entire day.
use that as a multiplier along with the panel spec in amps

have you decided on a refer yet?

without solar, 200 ah capacity batt bank, 3 days of 30ah is 90ah

[marquette]

I found a chart somewhere in my research that said 4-5 hrs summertime in Minnesota. I'll have to use a generator spring and fall. My goal is to get 3 days with no generator in the summertime.

[red31]

http://www.solarelectricityhandbook.com/solar-irradiance.html

I think you will find from the above solar calculator that the multiplier for hrs of full sun a day varies widely by location, time of year, angle tilt ...

[Boon_Docker]

200 watt would be better considering that you will not always get full peak sun everyday. A charge controller is used with solar panels to regulate the charge going into the battery.

[marquette]

So a 100 watt panel would give me close to what I need. Can I oversize? Would 200 watt be prudent or overkill that could harm the battery?

[NinerBikes]

marquette wrote:
Thanks for the info on the fridge. I'll use the 18 amp hr for the fridge. Adding that to my LED lighting, water pump and 4 hrs of Fantastic fan time I should about 30 amp hr per day.
I don't understand the solar charging table. Is it saying that with a 198 watt panel it would replace 10.5 amp hr in the battery each hour of peak sunlight? Meaning that given a 6 hr charge per day it would replace 63 amp hr per day.

That would be correct.

[marquette]

Thanks for the info on the fridge. I'll use the 18 amp hr for the fridge. Adding that to my LED lighting, water pump and 4 hrs of Fantastic fan time I should about 30 amp hr per day.
I don't understand the solar charging table. Is it saying that with a 198 watt panel it would replace 10.5 amp hr in the battery each hour of peak sunlight? Meaning that given a 6 hr charge per day it would replace 63 amp hr per day.

[scrubjaysnest]

Our pump draws 6 amps per the TriMetric.

Here is a way to determine how much solar you need based on the Ah rating of your battery(s) at the 20 hour rate.

based on a 5% to 13% typical rate of charge. 5% is OK for weekend/seasonal use, 10% or above is recommended for full time off grid charging (and if you have "significant" day time inverter/battery loads:
• 210 AH * 14.5 volts charging * 1/0.77 panel+charge controller derating * 0.05 rate of charge = 198 Watt array minimum
• 210 AH * 14.5 volts charging * 1/0.77 panel+charge controller derating * 0.10 rate of charge = 395 Watt array nominal
• 210 AH * 14.5 volts charging * 1/0.77 panel+charge controller derating * 0.13 rate of charge = 514 Watt array "cost effective" maximum
Just remember at best you will get 6 hours per day of charging.

[doughere]

The water pump draw probably isn't worth the time to add it in.

If you have an electronically controlled refrigerator it is your largest continuous load.

My Dometic refrigerator draws about 1/2 amp with the burner off, and 1 amp with the burner on. I figure 18 AH a day.

[beemerphile1]

Figure 8a but it will take less than five minutes to pump 12 gallons so it isn't worth worrying about.

[korbe]

Ours was tested at 4.5 ah.