David Baillie

[quote=Tom Berens]Anyone know where I can get some diodes?... Lol[/quote]these days digikey Ebay robotshop or amazon. Dirt cheap.

[quote=Tom Berens]I picked up some older panels, { kyrocea kc-80 } when I test them in full sun, putting out 20 volts, when I hook them to charge controller they drop to 9-11 volts and drain the battery. Any help out there?

Tom[/quote]hmmm.
The first step is double checking polarity, then checking the charge controller. After that you would want to check the diodes on the panels. If the diodes blew you could drain the battery through the panel.

A chest freezer for refridgeration can be accomplished with a very modest solar budget compared to the benefits refridgeration offers. Of course local, seasonal, season extension must play a part but refridgeration is a big deal. I live in the land of cold so I would not put refridgeration and AC in the same league.
Cheers,
David

You could use a corrosion inhibitor like they do for outdoor furnaces... something like this one. https://altheatsupply.com/wood-furnace-parts-accessories/maintainance-treatment/inhibitors-rust-scale.html

Douglas Alpenstock wrote:I have tried this, with decidedly mixed results.

The NiMH batteries in solar lights are very low capacity, typically 600 mAh in an 'AA' size. If you put in higher capacity batteries, they will never charge properly. (For example, the NiMH AA batteries I use have ranges between 2000 and 2650 mAh, almost 4x the capacity. Even AAA batteries run 800-1000 mAh. Sometimes you can get low capacity AAs at dollar stores.)

If you put the solar light AAs in other items, you may find they are slightly smaller or thinner, leading to intermittent contact. Spacers of aluminum foil or paper will help.

Bottom line, for me, is that solar lights definitely cannot take the place of a decent quality charger.

Do amp ratings matter in this case other then duration of charging? Voltage is the same  for all 5hose rechargeable so that should be what the charger is using. I have not tested this. I do agree it would be of lower quality then a dedicated charger.
Cheers,  David

It should work just fine. There is a small buck boost circuit in most of them to charge in even so so light. I have changed out some of the batteries that come with them with what I considered worn out nmhd rechargeable batteries and got much better winter use out of them. When I put it on the meter though I noticed mine only charged when the switch was in the on position. That's obvious but in the on position the light then goes on at dusk draining what you made. So if I wanted to use it as a battery charger I would make sure to turn the switch to off at night, and back to on during the day. It would build up slowly but should work.

M James wrote:David, the appliance repairman said a surge protector wouldn't do any good, which didn't sound right. We've never lost anything before due to flickering of electricity. Maybe just bad luck?

Another person on permies said his very large freezer just sips power, so your post confuses me (which ain't hard to do...see below lol).

I was under the impression that a dc chest fridge run on solar wouldn't use as much power as an ac one run on solar. One reason i thought that is because the dc (power) wouldn't have to be converted to ac to be used on solar, but ac would. Hope you get my drift. I'm not considering an ac freezer. The only reason ac came into my post was that if something happened and i needed to plug it into the grid, i could. Like if the sun didn't shine for a week or something.

Here are the components i already have, which i bought a few years ago for a different project:

Renogy rover mppt 20a pwm solar charge controller 12/24v. Max solar power = 12v 260w. Or 24v 520w.   Max load power = 12v 240w. Or 24v 480w

Mighty max solar 500w pure sine wave inverter. Dc to ac (in case i do decide to get the ac chest freezer)

The sundanzer chest fridge, in 90 degree air temperature, uses 240 wh/day. If my calculations are correct, this would make it 20 amps, but that sounds like an awful lot of amps. That can't be right. Probably has something to do with it being watt hours instead of just watts?  Ok then, is it 240 ÷ 24 hours in a day? If so, is it .83 amps?

Somebody please help me or else put me out of my misery LOL!

To clarify the total amount of power used by a modern ac chest freezer that is energy star rated converted to a fridge will be extremely close to its dc equivalent at a much lower price. The dc chest fridge's advantage is they can run directly off of a 12 volt battery so you do not lose any power converting from dc to ac. If you look at the dc appliances specifications in freezer mode and compare it to a standard one you will see for yourself. You wont find specs for a standard chest freezer in fridge mode so you need to compare freezer to freezer.
.83 amps is your hourly amps. Your fridge wont be running all the time. Running amps is probably in the 8 amp range when it's on. So 12 voltsx8 amps for 96 watts When its running probably in the 10 to 15 percent duty cycle range or 9.6 ish watts per hour...
Cheers,  David

M James wrote:Hey all! I just signed up today and am excited to have joined a forum with like minded folks.

I'm into self sufficiency and my goal is to go completely off grid sometime in the future, one thing at a time. We have been using solar powered lighting in the house for over a year now and we love it.

During a wind storm about a month ago the power flickered several times and fried the compressor in the chest freezer we had been using for a year as a fridge, so getting refrigeration is first. Side note: the chest "fridge" saved us a lot of money on our electricity bill each month.

After that is wood heat, but our setup isn't ideal. Insurance company won't insure us unless a licensed pro installs the rocket mass heater. We know of nobody in this area that does that and we absolutely cannot afford to bring ernie and erica over here to do it. So, it will most likely be a wood stove. My desire is to use the wood stove to cook and bake as well as heat our home and heat water. Already use my solar oven to cook and heat water but it isn't gonna heat our home and it only works on sunny days lol!

I would like to buy a sundanzer chest fridge and run it on solar, with the option to run it on ac if we need to. Looking at their dcr154 5cf chest fridge. Gonna call and ask if they can install an ac thing. I have some solar components already but am in need of solar savvy folks to guide me.

Nice to meet you all!

Welcome to permies...
You are going to get two opinions on the 12 volt freezers. They are a good unit but do not use less energy then their off the shelf big box store freezers of the same size that are energy star rated. So if you are considering the ac model anyways I would say that you buy a standard one and spend the extra money on a starter off grid system. The extra 1000 dollars for the sundanzer will get you 2 deep cycles, solar panels, controller and a small inverter to run it...  just a thought. I know people who have them love them though.
A good surge protector power bar is a very good investment as well...
Cheers,  David

Tim Comer wrote:I'm confused about sizing an array with a charge controller...  If I go with five 210w panels (specs below) what specs do I need to consider for the compatible charge controller?  Would I need two Epever Tracer4210AN charge controllers for this array?  Is there a problem with two charge controllers?

I don't know what battery bank I am looking at yet, but considering one 200aHr Chins 12v.


Panel specs
Max Power Output(W): 210W
Voltage MPP Vmp(V): 16.77V
Current MPP Imp(A): 12.48A
Voltage Open Circuit Voc(V): 19.83V
Short Circuit Current Isc(A): 13.09A

Here is a link to epevers site... under documents
Your max ocv is listed at 92 volt. Max watts 520. https://www.epsolarpv.com/
You might be able to get away with 3 but you will risk burning out the charge circuit. You would use 2 40 amp chargers if using a 12 volt system one with 1 string of 2 and one with one string of 3 but again its risky. The charger voltage is based on your battery bank voltage. An mppt charger reduces the solar voltage down to your battery voltage and gives you more amps...
Cheers,  David

I would agree an open voltage of 22 or 23 volts is not unusual on a 12 volt panel. Please dont tear it open yet. I would try the 3 panel experiment on the mppt charger first. 1.5 times battery voltage for an mppt string is very common. A 24 volt string open circuit voltage up to 50 volts will not power my mppt charge controller.  I use an outback 60 amps charger. Do you have a make and model for the charger?