How to calculate useage

[mike2scuba]

thinking of getting a slow cooker rated between 150w to 200w to run off my set up i have in my garage.

i have 2x 120w solar panels going into a 100 amp leisure battery via a 30 amp solar controller.
also have a 600w pure sine inverter connected to the system

Crock-Pot, use between 75 and 150 watts of electricity on low and between 150 and 210 watts on high settings

question is how long could i run the slow cooker which has a low and high setting
thanks in advance

 

[Glots222]

Get a watt meter and plug in the pot for a few hours and see exactly how much power it uses. (Probably cycles on & off).
Divide total battery watt hours available by pot usage.

 

[Madco]

Usage will be calculated as load power multiplied by hours. That will give you energy in Watt hours. Not knowing more, I would average the power consumption on each setting, so 113W on low and 180W on high. So, say it. cooks for 2 hours. Energy consumption on low would be 226 Wh on low and 360Wh on high.

You didn't mention your battery capacity, but to determine total cook time available, assuming no other loads, divide the battery capacity (in Wh, not kWh) by either 226 or 360. That will be an absolute maximum cook time. It will probably be closer to 70% of the ideal calculation.

 

[SamDeleted]

thinking of getting a slow cooker rated between 150w to 200w to run off my set up i have in my garage.

i have 2x 120w solar panels going into a 100 amp leisure battery via a 30 amp solar controller.
also have a 600w pure sine inverter connected to the system

It's really simple

100ah leisure battery:

100ah X 12v = 1200wh

But then they are only rated for 50%dod(depth of discharge)
, so 600wh usable capacity

600wh ÷ 200w cooker = 3hrs cooking time on high...



But that's just on battery power, you should be able to cook almost indefinitely so long as the sun is shining on your solars panels

 

[SeaGal]

Slow cookers are usually not thermostatically controlled, so just on high or low. Obviously the time you can power it for will depend on the state of charge of your battery and how long the sun is shining too.

 

[Solarcabin Channel]

I just want to know where you found that low watt slow cooker and something I would be interested in.

Your system should be fine for that if you run it in the day time or night if the batts are full.

 

[SeaGal]

All slow cookers are rated around that wattage in the UK - mine measured as 120W low power and 180W high power - 230V AC obviously.

https://www.argos.co.uk/product/7242524

 

[cba]

All slow cookers are rated around that wattage in the UK - mine measured as 120W low power and 180W high power - 230V AC obviously.

https://www.argos.co.uk/product/7242524

Yes that was the one I was thinking of getting

 

[Solarcabin Channel]

Doesn't look like that cookworks is sold in the US but Elite Gourmet has one a bit bigger and 380 watts. I have a few of their appliances and pretty well made so looks like that will go in the cart.

Thanks!

 

[cba]

Get a watt meter and plug in the pot for a few hours and see exactly how much power it uses. (Probably cycles on & off).
Divide total battery watt hours available by pot usage.

Have got a renology shunt so this should give me an accurate measurement of incoming and outgoing electricity and time remaining.
Just wanted an idea if it was possible to run one before purchasing

 

[cba]

Will all be sharing menus soon lol

 

[SeaGal]

Doesn't look like that cookworks is sold in the US but Elite Gourmet has one a bit bigger and 380 watts. I have a few of their appliances and pretty well made so looks like that will go in the cart.

Thanks!

Interesting, just had a look and most USA ones are much higher power. I can only guess that they are thermostatically controlled (i.e. on and off) otherwise the food would be dried out after 8 hours at 1000W+

I did spot this USA one using just 163W... it looks more similar to what we have in the UK, but sold out at the moment.

https://www.amazon.com/ICOOK-USC-35-OP001BL-Aluminium-Dishwasher-Adjustable/dp/B0B4FN2NYN

 

[SeaGal]

Will all be sharing menus soon lol

Here you go... https://www.mumsnet.com/talk/_chat/4862970-tell-me-your-favourite-slow-cooker-recipe

 

[mike2scuba]

0k i have plugged the slow cooker into the inverter and got this reading on the shunt monitor.

so given this reading the cooker should run to 6 hours 30 mins to discharge to 50% given all factors stay the same.

 

[Solarcabin Channel]

so given this reading the cooker should run to 6 hours 30 mins to discharge to 50% given all factors stay the same.

Now watch that and tell us how often and how long the slow cooker runs over an hour. Let's see if it is steady or intermittent.

 

[SeaGal]

Now watch that and tell us how often and how long the slow cooker runs over an hour. Let's see if it is steady or intermittent.

I'm pretty sure it will be constant... these low power UK slow cookers don't have a thermostat (well, certainly the 2 I've had in my life don't).

They just keep the food slowly bubbling with the 100 - 180W element. The only downside is they take about an hour to get things up to temp in the first place, not that that matters, if they're running for 6 to 8 hours.

 

[cba]

Monitored the slow cooker on house electrics today on low setting. The device stayed static at 136.7w over 8 hours.
Now if I divide 137.7w by 12v it equals 11.39 amps.
If the battery is 100 amps and I want to run it to 50% the device would run for 4.38 hours without any solar charging.
If I add another 100ah amp in parellel this would double the time to around 9 hours which would cover the 8 hours required to cook. Any solar charging over the 8 hour period would be a bonus.
Are the figures I have worked out correct or have I overlooked anything