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Old 02-01-2017, 01:55 PM   #1
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Instant Pot while boondocking.

Hi everyone, this is my first time posting, though I'm sure not my last. We've had our Sportsmobile 144 for the last few months and have totally loved. We are getting ready to live out of our van with the family for two months this summer and would like some help figuring out what we can and cannot run off of out battery/solar system while boondocking

Specifically, we could like to know the feasibility of running our Instant Pot electrical pressure cooker without "zapping" our battery in a test trial. It looks like it use 1,000 watts on 110v. I believe that means is uses 9 amps (1,000w / 110v).

In regards to out system:
Inverter: Magnum 2,000w 100amp
Battery: AGM 4D (200ah)
Solar Panels: Zamp 100w x2

Energy Draw:
-Refrigerator: 2.7cf, 12v 2.5A
-Microwave: not used much.
Other than that, it's just the house lights.

Thanks for looking at this and we appreciate your help.

nwr
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Old 02-01-2017, 02:57 PM   #2
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I totally thought this thread was about something else.
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Old 02-01-2017, 02:58 PM   #3
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As for your question, daveb is good at all this math stuff. Dave?
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Old 02-01-2017, 03:14 PM   #4
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Convert that 1000 Watt draw using 12 Volt as it comes back through your inverter. So that's an 83 Amp Draw really less your inverter efficiency. I don't know inverter efficiencies but let's just say it's 90%

then 83 Amps/0.90 inverter efficiency is 92 amps of draw at full power.

That's not great.

boywonder did some calcs on his electric hot water heater vs propane etc and it's pretty surprising how much energy propane actually has. I know I will be cooking over propane, Isobutane, or butane when camping.

Sorry to ruin your dinner.
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Old 02-01-2017, 04:09 PM   #5
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Greetings rj9294, How many 4D 200Ah batteries do you have? If only one then that is a lot of amps to try to coax out of a single battery let alone over any length of time and if the battery temperature is below an ideal 77*F. You have an awesome inverter and 2000w is a useful size, but I would recommend more battery than one 4D to get it's full potential.

Your math is correct but when you invert the 1000 watts or 9 amps x 110 volts to 12 volts it's going to look something like 1000 watts divided by 12.5volts (or whatever your voltage gets drawn down to, possibly 11.5v) X 1.15 (inefficiency of the inverter, Magnums run around 15% loss under significant load) so possibly around 100 amps or more of DC. Again, a lot for one battery to try to produce, reasonable for two 4D's to handle. If you only have one battery you probably wont hurt it to try it in the driveway but I wouldn't try to pull 100 Amps off an older tired house battery for risk of accelerating a soft short. You definitely wont hurt the inverter for it will disconnect automatically at the low voltage setting. Two batteries I think would be the ticket for your inverter size.

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Old 02-01-2017, 04:31 PM   #6
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If you have room to store it, maybe invest in a 2000w inverter-generator if you plan to boondock a lot. Honda is the standard, of course, but there are some cheaper knock-offs out there now (e.g., Harbor Freight for $500) that may meet limited needs.
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Old 02-01-2017, 04:48 PM   #7
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Thank you everyone for your help and insight. In regards to the batteries, yes, we only have a single 4D. Moving forward, I might have to look at getting another one.

I'm curious how many amps the Instant Pot/pressure cooker actually draws vs what it "can" draw. I'm thinking one possibility would be that in the initial cooking phase when the pot comes up the temperature and pressure, the draw will be at maximum, but then later the power consumption will decrease during the maintenance or pressured phase of cooking. Could I idle the engine to power the inverter off the alternator during heavy draw, then let it run off the battery after it is pressurized?

Online, I was able to find that the Instant pot plugged into a household outlet was able to bring 3L of water to working pressure (11.6psi) and hold it at temperature using 0.35~0.36 KWH. Is this at all helpful in determining actual load?
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Old 02-01-2017, 05:20 PM   #8
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Quote:
Originally Posted by rallypanam View Post
I totally thought this thread was about something else.
Yes, I was going to suggest a vaporizer.

But regarding your electrical requirements. I would avoid such an appliance. Just buy pre-cooked foods at deli's, supermarkets, etc and heat them in the microwave. So much easier and you'll recover a lot of leisure time to enjoy.
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Old 02-01-2017, 06:00 PM   #9
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Quote:
Originally Posted by rallypanam View Post
I totally thought this thread was about something else.

me too........


Quote:
Originally Posted by Flux View Post
Convert that 1000 Watt draw using 12 Volt as it comes back through your inverter. So that's an 83 Amp Draw really less your inverter efficiency. I don't know inverter efficiencies but let's just say it's 90%

then 83 Amps/0.90 inverter efficiency is 92 amps of draw at full power.

That's not great.

boywonder did some calcs on his electric hot water heater vs propane etc and it's pretty surprising how much energy propane actually has. I know I will be cooking over propane, Isobutane, or butane when camping.

Sorry to ruin your dinner.
what he said.....

Quote:
Originally Posted by ShuttlePilot View Post
How many 4D 200Ah batteries do you have? If only one then that is a lot of amps to try to coax out of a single battery let alone over any length of time and if the battery temperature is below an ideal 77*F.
-Eric
yup....people often neglect the output impedance of the battery when using larger inverters......

Quote:
Originally Posted by rj9294 View Post
Online, I was able to find that the Instant pot plugged into a household outlet was able to bring 3L of water to working pressure (11.6psi) and hold it at temperature using 0.35~0.36 KWH. Is this at all helpful in determining actual load?
yes, but my brain is fried tonight......actually, in order to calculate amps, we need to know how fast the cooker brings the water to the target working pressure.

If it did that in about in 30 minutes (not exactly "instant" )....then:

.35KWH=350 watt-hours

(350 watt-hours)/.5 hours=700 watts

700 Watts/12.5V=56 amps (12.5V courtesy of shuttlepilot!)

If it got to operating temp/pressure in 15 minutes then 112 amps or so...
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Old 02-02-2017, 06:44 AM   #10
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We have and use a 1000w Hot Pot. BUT use it to only heat water occasionally. Takes about 5 minutes to boil and therefore sucks about 8-10 Ah out of our house batteries in that 5 minutes. Normally use our Colman stove.
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