#171413  by Paul-Carter
 Tue Mar 16, 2021 8:25 am
Totally with you on this.
 #171414  by Neddy
 Tue Mar 16, 2021 8:46 am
Mark, what exactly is your "standard" fridge? If it is a 3-way running on LPG your electrical needs are minimal and a fairly low-spec solar system will be all that is required. If you are running a 12 volt compressor fridge, the amount of solar power you need will vary widely, depending on the actual model. Some take less than an Amp to run, while others can be 5 Amps or even more. Either way, a compressor fridge is usually a significant power user and any solar system needs to take this into account.

 #171456  by Skiwi
 Thu Mar 18, 2021 6:59 am
If I was starting from scratch again, I’d max out on solar with a matching controller and about 100ah lithium, then see how it went, it’s easy to add additional batteries later if required.

Or, you could do the detailed energy audit, but in reality it’s just high or constant current draw items that will tip you into bigger battery territory.

 #171458  by Neddy
 Thu Mar 18, 2021 9:54 am
I agree 100%. We had the luxury of starting from scratch with a clean slate and did almost exactly what you propose, fitting 740 Watts of solar power to charge a 100Ah AGM battery. This array ensures that our House battery is fully charged every day - regardless of weather conditions, location or time of year. (No reason to ever plug into mains power). We have no "high or constant current draw items" and with an overnight battery drawdown of around 30 AmpHours (measured, not estimated!) our battery has an easy life and I expect it to last a long time.
A "Detailed Energy Audit" sounds good, but in reality it is likely to be little more than the sum total of a long series of rough estimates and outright guesses. I always advise those that are unsure of their electrical requirements to fit a Battery Monitor and get some facts to work with.
 #173242  by deLacy
 Tue Jun 08, 2021 4:31 pm
I have an Isotherm CR85 fridge and the specs say "average power consumption is 15 watts" Is that 15 watts continuously, hourly, daily or what? I am about to install this fridge and I have a 100w panel. I have plenty of battery storage. The batteries only run the fridge, a few LED lights and the water pump. I don't stay in one place very long and usually move on every two days.
 #173243  by mattn
 Tue Jun 08, 2021 5:36 pm
Average is 15W, so 15*24 hours = 360 Wh, about 30Amp hour. You will find a 100W panel in winter won't be large enough. You will average about 150Wh - 200Wh from it - no matter how big you batteries, you are taking more from them than putting in. In summer this will increase to about 600Wh so you will have enough to run the fridge if you manage power use carefully.

Unless you have a Lithium battery or drive long distances, charging from driving won't help much. Lead batteries will quickly drop to taking only 10-20Amp charge, and do not last long if left discharged for long periods of time.

You really need to add more panels unless your only use is summer time.
 #173244  by David Wallace
 Tue Jun 08, 2021 5:37 pm
A internet search say it draws 380w over 24hrs. So that is would be 15Kw an hr. See this link for more details
https://www.marine-deals.co.nz/fridges- ... i0EALw_wcB
 #173252  by Neddy
 Tue Jun 08, 2021 7:55 pm
Warren, your fridge power consumption over 24 hours will be about 360 or 380 Watt Hours. You want to run a few other things as well, so a reasonable solar power requirement for you might be about 500 Watt Hours/day. Here are some monthly average figures (for Lower Hutt) showing the panel capacity you would need to supply this.

January 80 Watts
February 90 Watts
March 114 Watts
April 166 Watts
May 235 Watts
June 300 Watts
July 270 Watts
August 200 Watts
September 136 Watts
October 100 Watts
November 85 Watts
December 80 Watts

Head South and you would need more than this, head North and you could get away with a bit less.
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