Deep Cycle PV and Camping

Nountaineer

I have been experimenting with 100 watt PV panels while camping to run my Coleman electric cooler. I have fried a few Sun Force charge controllers when it tries to recharge a deeply discharged battery when the sun comes up. The cooler must run all night to keep my food from spoiling. I am working on my mining claim for a week at a time and must rely on this type of system instead of ice. I use 2 100 watt PV panels from Home depot. I have a couple smaller panels as well that I used to melt (almost) one of their 7 amp models to see if it could handle a little more than rated. What can I use as a controller that works down to 7 volts when the sun arrives again? I already have one large deep cycle battery (a hernia maker). Any ideas?

Cariboocoot

Re: Deep Cycle PV and Camping

Welcome to the forum.

Okay, the first thing you need to do is determine how much power that cooler is using. It is probably a Peltier/Seebeck type device (no compressor) which draws a pretty hefty current all the time.

The second thing you have to do is make sure you have enough battery capacity to handle that current demand over 24 hours without drawing the battery below 50%. 25% is better.

The third thing is to have enough panel and the right size charge controller to recharge that battery.

A 100 Watt "12 Volt" (17.5 Vmp) panel can produce just under 6 Amps of current max. If you had two in parallel you would need at least a 15 Amp charge controller to handle it. A lower rated one will fry.

You mention drawing the battery down to 7 Volts. That is a dead battery. Dead as in "unlikely to be recharged to usable no matter what you do to it".

Someone will probably suggest looking into adapting a propane 'frige from an RV and taking along a tank. Might as well be me. I recognize that this may not fit with your ideals of portability though.

How big is this battery you have in Volts and Amp hours (at the "20 hour" rate)?
And do you have any specs for the current draw of that cooler?

BB.

Re: Deep Cycle PV and Camping

And, you might look into a used RV Absorption refrigerator/freezer and run it from propane.

There are more efficient small refrigerators using compressors.

Here is one thread that discussions the options (including converting a chest freezer into a refrigerator--Probably one of the lowest power devices).

Solar Refrigerator

Usually, it works out if you are using a fridge for 9+ months a year, an Energy Star fridge (or chest freezer conversion) can be very cost effective.

If you are weekends/seasonal, then an absorption fridge/freezer running from propane may be the better deal.

-Bill

icarus

Re: Deep Cycle PV and Camping

Buy a Propne fridge!

Tony

niel

Re: Deep Cycle PV and Camping

another point here concerning those coolers is that even if the cooler reaches the desired temp good for keeping your food that unless they incorporated a thermostat that the peltier device(s) will keep drawing power and these are about from 4a to 10a each depending on the device used. an average battery being about 100ah would have about 50ah useable for preserving battery life and these devices would suck that 50ah down fairly quickly. a battery is considered dead if its at rest voltage is at 10.5v. odds are you've hit that point nearly every night you've used it so you need another type of refrigeration than this. i suspect all will be hernia makers as this is not something to easily transport complete with its own power to run it. even propane is heavy to move as you would most likely need a 5 gallon type tank.

mike95490

Re: Deep Cycle PV and Camping

niel wrote: »

another point here concerning those coolers is that even if the cooler reaches the desired temp good for keeping your food that unless they incorporated a thermostat that the peltier device(s) will keep drawing power and these are about from 4a to 10a each depending on the device used. .....

And most thermostats can't switch much DC power

niel

Re: Deep Cycle PV and Camping

good point mike, but they can switch a relay in and that would be another load, albeit a small one, to run the relay.

PNjunction

Re: Deep Cycle PV and Camping

To get the most out of it, you'll definitely need to calculate your power draw. You'll also want to know your solar-insolation hours, which differ from mere sunrise-to-sunset hours. The hours you get vary on location and environment, so be sure to search for solar-insolation charts. Most use the "winter" hours when doing a power budget calculation to give themselves some headroom.

For your smaller projects, junk those 7A Sunforce charge controllers. They are just simple on-off mosfet types that ping-pong between an upper and lower voltage limit (14.6 and 13.2) based on the hysteresis of the battery itself. By all means upgrade to at least a PWM type controller for your typical <250 watt nominal 12v systems such as Morningstar Sunsavers - which also have ambient temperature compensation to boot.

Nountaineer

Re: Deep Cycle PV and Camping

Cariboocoot wrote: »

Welcome to the forum.

Okay, the first thing you need to do is determine how much power that cooler is using. It is probably a Peltier/Seebeck type device (no compressor) which draws a pretty hefty current all the time.

The second thing you have to do is make sure you have enough battery capacity to handle that current demand over 24 hours without drawing the battery below 50%. 25% is better.

The third thing is to have enough panel and the right size charge controller to recharge that battery.

A 100 Watt "12 Volt" (17.5 Vmp) panel can produce just under 6 Amps of current max. If you had two in parallel you would need at least a 15 Amp charge controller to handle it. A lower rated one will fry.

You mention drawing the battery down to 7 Volts. That is a dead battery. Dead as in "unlikely to be recharged to usable no matter what you do to it".

Someone will probably suggest looking into adapting a propane 'frige from an RV and taking along a tank. Might as well be me. I recognize that this may not fit with your ideals of portability though.

How big is this battery you have in Volts and Amp hours (at the "20 hour" rate)?
And do you have any specs for the current draw of that cooler?

Thank you for the good points. I went to Coleman's website for data on this cooler but since it was one of the first produced, there was no wattage or other info. available. The cooler kicks in and out all night to defrost I think. My battery is 114 amp hours-85 marine cranking amps. I just put my Fluke 179 true RMS meter on the battery which has set for 1 week since I recharged here at home and it was 11.85 volts so I may have done some damage to it. I just put the charger back on it to see if it will take a full charge. I normally put frozen jugs of water to assist which helps keep things cold for the first few days as well as multiple layers of blankets over it.

The local thieves have stolen 2 propane refrigerators which gets a little costly. My 17 foot RV was totally trashed as well. I am just north of the Mexican border in S.E. AZ. which makes it a little dangerous to leave anything behind. I would need to dedicate a trailer to food handling with another propane fridge. My vehicle is packed full of everything I might need if I get stranded up there, including weapons. The smugglers carry AK 47 automatic rifles which makes things rather dangerous. Anyone interested in watching my back? They are watching me. I also forgot to check the "send email " so I came back to see if there were any responses.

Cariboocoot

Re: Deep Cycle PV and Camping

Your battery is toast. Resting Voltage of 12 would be 50% SOC and yours doesn't make that. It is highly unlikely it will charge back up. It isn't a very good choice of type to begin with, as the Marine batteries are basically automotive types with thicker plates. They don't stand up well to repeated cycling such as in an RE application. The 114 Amp hours also wouldn't provide much power against that cooler's draw.

Look at it this way: if the cooler pulled only 5 Amps average in twelve hours overnight that would be 60 Amp hours, more than 50% of the battery's capacity. At that point you're in trouble.

Can't help you with the security issues other than to suggest it doesn't sound like a very fun vacation spot. Have you tried Canada?

BB.

Re: Deep Cycle PV and Camping

Cariboocoot wrote: »

Can't help you with the security issues other than to suggest it doesn't sound like a very fun vacation spot. Have you tried Canada?

We watch "Flashpoint" -- Toronto appears to be more dangerous that our major troubled cities

(Flashpoint is a pretty good SWAT type program out of Toronto that just ended its 5 year run last year).

-Bill

Cariboocoot

Re: Deep Cycle PV and Camping

Bill; Toronto isn't Canada, it's Toronto.

Other than the cities, our country isn't too bad in terms of crime. Funny how if you cram a lot of people into a small space they tend to get nasty, eh?

BB.

Re: Deep Cycle PV and Camping

Oh--I was just having fun... While any big city has its share of crime--TV shows are hardly representative of what is truly going on. Psych is another fun "cop show" filmed in British Columbia but "set in Santa Barbara California"--They solve a dozen murders a season whereas Santa Barbara has between 0-3 murders per year...

Back to your regularly scheduled programming.

-Bill

niel

Re: Deep Cycle PV and Camping

if you wish to continue with an electrical need for refrigeration and as long as you are going with the 12v pvs and would still like to expand upon the solar aspect then you may do so, but you need a better pwm controller as you stated. something like these would allow for more pv current.
http://www.solar-electric.com/xachco.html as in the c line of controllers, but mppt is fine to use too if you wish top end.

of course there are others out there too such as morningstar. http://www.solar-electric.com/stpwmchco.html

i'd be curious what it is you are mining.

a rough guide would be the pv wattage divided by the battery voltage to show the minimum current capacity needed by the controller.

you would probably need to upgrade the battery capacity as well and more carefully monitor its soc. old battery is gonzo.

Nountaineer

Re: Deep Cycle PV and Camping

Cariboocoot wrote: »

Your battery is toast. Resting Voltage of 12 would be 50% SOC and yours doesn't make that. It is highly unlikely it will charge back up. It isn't a very good choice of type to begin with, as the Marine batteries are basically automotive types with thicker plates. They don't stand up well to repeated cycling such as in an RE application. The 114 Amp hours also wouldn't provide much power against that cooler's draw.

Look at it this way: if the cooler pulled only 5 Amps average in twelve hours overnight that would be 60 Amp hours, more than 50% of the battery's capacity. At that point you're in trouble.

Can't help you with the security issues other than to suggest it doesn't sound like a very fun vacation spot. Have you tried Canada?

Thanks for the input. I recharged the battery overnight and it is holding at 12.88 volts after sitting for a few hours. I will see what might be available along the RV fridge route. Since I have about $500 invested already, I may upgrade the battery and controller if a fridge is not available in my "small town" of Patagonia, AZ. Thank you for your expert advice.

Nountaineer

Re: Deep Cycle PV and Camping

Thanks Niel, I am not yet in production with my "silver mine". I just found a new type of silver ore that needs to be tested. I bought a near new condition Case 1845C skidsteer loader with backhoe attachment from a custom home builder in Phoenix in 2008 and am hoping to put it to work soon, if possible. I will work on beefing up my system as finances allow. Thanks for your help.

SolarPowered

Re: Deep Cycle PV and Camping

I am just going to make a few recommendations.
I would have a minimum (3) 125Ah batteries. I use the VMAX tanks brand, its been very reliable for the conditions, its the biggest bang for your buck battery at the moment. There is an amazon.com vendor that will sell a bank of 4 at a discount with free shipping, you may want to go that route.
Get a better PWM charge controller with MOSFETS. It sounds to me that the charge controller you are using is a sunforce/Brunton/Harbor Freight 7amp controller its the same circuit board and its really popular from china. Its a very limited controller with 1 stage for charge controlling, it doesn't have a 2 or 3 stage charge control.

Just for a basic compressor fridge is what I would design around. a 3 CU/FT fridge once brought up to operating temperature control can consume between 150~200watts, however start up a fridge can consume roughly 400watts an hour.

I would design around a compressor fridge that can consume at start up 400watts.

-800watts in panels (12V panels, 18Vmp, 20~22Voc)
-30 amp digital charge controller (make sure it has MOSFETS, 3 stage)
-3 batteries
-400 watt pure sin wave inverter (800 peak surge)

Since you have a problem with theft I would look into investing into a KNACK BOX, I'm in the construction biz and have had loads of tools and solar equipment stolen. Until I had the KNACK box, it was my savior. Craigslist you can find them used for under $100.

I sell solar generators and most of the consumer questions revolve around can I power my fridge and for how long. I tell most of them for 120watts in panels and (1)125Ah battery to tote around its only enough to suffice for an "average" 1/3 of a 24 hour period @ 50%DOD, which means eventually it would start doing what your charge controller is doing getting hot and melting. I don't sell my generators to consumers unless I have to deliver proper expectation that it will take additional panels, and an additional battery bank to plug into the generator. I don't want damage to my equipment, or existing equipment (such as a fridge).

If you ever watch gold rush you will figure out that it takes the right equipment to get the job done right, and any sub par equipment actually adds constraints to a project. Solar is an investment to better the opportunity. Spend the money, get it done, right, and the future investment or return on investment will be that much more fruitful.

SolarPowered

Re: Deep Cycle PV and Camping

If you just need something small 12V~4.5amp, 54watts per hour. Has a 4 of 5 star review on Amazon.com. 576 ounce capacity that's just slightly higher than 1 cu/ft.
Then you could run it on your 100watt panels, however I don't believe these refrigerators get very cold.
http://www.amazon.com/Koolatron-P27-Voyager-Cooler/dp/B000Q73C66/ref=sr_1_1?ie=UTF8&qid=1376870591&sr=8-1&keywords=12+volt+fridge

Cariboocoot

Re: Deep Cycle PV and Camping

The Koolatron is a Peltier/Seebeck device. They don't actually cool to a specified temperature, but rather reduce the interior temp by 'X' degrees in reference to the outside temperature. This may not provide sufficient cooling in hotter climates. Furthermore they draw a significant amount of power all the time.

Until you know how much power you actually need to supply you can't pick any battery to do the job.

Nountaineer

Re: Deep Cycle PV and Camping

Thank you Cariboocoot and Solar Powered, I just ordered the 35 amp Schneider Electric controller (PWM) last night. I used the links provided by Neil and after a brief comparison chose the Schneider brand unit. I can use my fluke meter to measure the DC amperage draw then use the method for calculating battery size, provided previously. By the way, I am a disabled refrigeration mechanic with 25+ years experience so starting amps, locked rotor and running amps are familiar to me, and I have not considered using a compressor type refrigeration unit simply due to starting as well as running amp draw. I would only have room on the passenger side of my Isuzu Rodeo for two deep cycle batteries. I also contacted Coleman Technical support for the power consumption, I hope to hear back from them soon. Thank you for the additional information. I do want to do it the correct way this time instead of trial and error.

David

Shadowcatcher

Re: Deep Cycle PV and Camping

The Colman cooler is at best 40 degrees below ambient temperature, not safe for storing food.
We have a Teardrop trailer with a 180 W high voltage panel, this feeds a Morningstar SunSaver MPPT controller. Above and beyond the normal LED lights radio etc we have a Waeco 12V DC 120AC refrigerator that will keep things cold and can freeze easily. The refrigerator when being transported is in the back of our car and a line running from the battery to a PowerPole connector in the back.
We have a 150 AH AGM battery. We spent 8 days on the north shore of Lake Superior in a camp site with lots of trees. I had the option of recharging the battery using an additional 140W panel that could be rolled out in the sun (flexible panel) or from the tow vehicle alternator. but decided to see what would happen. We lost ground each day but at the end of eight days we were at 65% state of charge.
A friend of mine did a study of the Waeco CF40 power usage http://home.comcast.net/~bdosborn/Boxcar/Waeco_CF40.html
The Coleman's use about 4A continuously

SolarPowered

Re: Deep Cycle PV and Camping

Nountaineer wrote: »

Thank you Cariboocoot and Solar Powered, I just ordered the 35 amp Schneider Electric controller (PWM) last night. I used the links provided by Neil and after a brief comparison chose the Schneider brand unit. I can use my fluke meter to measure the DC amperage draw then use the method for calculating battery size, provided previously. By the way, I am a disabled refrigeration mechanic with 25+ years experience so starting amps, locked rotor and running amps are familiar to me, and I have not considered using a compressor type refrigeration unit simply due to starting as well as running amp draw. I would only have room on the passenger side of my Isuzu Rodeo for two deep cycle batteries. I also contacted Coleman Technical support for the power consumption, I hope to hear back from them soon. Thank you for the additional information. I do want to do it the correct way this time instead of trial and error.

David

If you want to measure DC amperage there were some shunt ammeter combos that I purchased from ebay. Makes it much easier than whipping out the fluke meter, and the accuracy of the shunt may be improved VS the fluke meter. Ships from Hong Kong, mine took 2 weeks to come in.
http://www.ebay.com/itm/170974108016?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

SolarPowered

Re: Deep Cycle PV and Camping

Cariboocoot wrote: »

The Koolatron is a Peltier/Seebeck device. They don't actually cool to a specified temperature, but rather reduce the interior temp by 'X' degrees in reference to the outside temperature. This may not provide sufficient cooling in hotter climates. Furthermore they draw a significant amount of power all the time.

I digress to some extent for a very simple reason, for the manner in which ambient outside temprature can be manipulated. Temprature can always be manipulated via heat exchange. True, Peltier works via ambient temperature, but that doesn't mean that ambient temperature cant be manipulated with a PC water cooling system

Basic 4 watt pump, and a 1 watt fan, with some non conductive coolant, you can get a peltier, pretty cold even in 100* ambient weather. Basic PC coolant system drops temperatures on PC's by 15* F.

Some, not all Peltier 54 watt systems exchange outside ambient temperature by 36~40*F, an additional 15* drop in temperature via PC coolant heat exchanger on a 100* day would put that drop around 51* to 55*F so on a 100* day using a PC heat exchange, peltier temperature can be exchanged to a very cold 49*~45*F. Only problem is it takes more watts to do it.

You don't need a thermostat manual control either to regulate a peltier, all you need is a thermostatic switch, or digital 12V controller connected inline to the load end of the circuit, and then it can conserve watts through out the day, making the system efficient as it would be more conservative than liberal on power consumption.. However I prefer thermostatic swiches VS controllers because controllers consume power unlike thermo static switches.

5 watts an hour for a 15*F drop.... I'll take it and still consume less power than a compressor fridge.

Heat exchanging is a very amazing thing.

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Nountaineer

Re: Deep Cycle PV and Camping

Shadowcatcher wrote: »

The Colman cooler is at best 40 degrees below ambient temperature, not safe for storing food.
We have a Teardrop trailer with a 180 W high voltage panel, this feeds a Morningstar SunSaver MPPT controller. Above and beyond the normal LED lights radio etc we have a Waeco 12V DC 120AC refrigerator that will keep things cold and can freeze easily. The refrigerator when being transported is in the back of our car and a line running from the battery to a PowerPole connector in the back.
We have a 150 AH AGM battery. We spent 8 days on the north shore of Lake Superior in a camp site with lots of trees. I had the option of recharging the battery using an additional 140W panel that could be rolled out in the sun (flexible panel) or from the tow vehicle alternator. but decided to see what would happen. We lost ground each day but at the end of eight days we were at 65% state of charge.
A friend of mine did a study of the Waeco CF40 power usage http://home.comcast.net/~bdosborn/Boxcar/Waeco_CF40.html
The Coleman's use about 4A continuously

This fridge looks like a possibility for a future project but I have room only for something like the small Coleman cooler that fits nicely on a rear passenger seat.

Concerning the Xantrex controller (Schneider Electric), can I add in parallel My smaller panels to the 2 100 watt PV ones which would add about 45 additional watts which would be well within the 35 amp capacity of the controller? I understand that the two batteries must be identical.

Buying the shunt device to measure the amperage just one time might be extra time consuming as well as an additional expense that can wait, but might be considered for a future project.

SolarPowered

Re: Deep Cycle PV and Camping

Nountaineer wrote: »

Concerning the Xantrex controller (Schneider Electric), can I add in parallel My smaller panels to the 2 100 watt PV ones which would add about 45 additional watts which would be well within the 35 amp capacity of the controller? I understand that the two batteries must be identical.

Do not connect the smaller, and larger panels together as 1 parallel string.
If it were me, I would of purchased separate 10 amp charge controllers to separate the larger panels from the smaller panels.

Nountaineer

Re: Deep Cycle PV and Camping

Thank you SolarPowered for responding. I took your advice, except that I found the sunforce pro (WPM) which is slightly smaller (8.5) amps yet has the additional circuitry similar to the Xantrex to handle the additional 45 watts. Also, it was only $26 plus shipping. Next is to find the best prices for the batteries (2) , and which brand and size to choose. I am thinking that 2- 150 amp hours, true "deep cycle" type batteries would handle my needs. Are there any additional comments concerning my choices from Cariboocoot, Neil or another expert? I am also figuring on a consumption of about 50 watts, since Coleman has not yet responded.

I am trying to limit shipping times etc. because I need to get back to digging for silver soon. I will likely have to drive to Tucson to find the batteries. My "marine" battery came from Walmart. It was the largest one available at that time.

SolarPowered

Re: Deep Cycle PV and Camping

For batteries, I Prefer.....

VMAX Tanks on amazon.com 125Ah is the biggest bang for the buck, if you are an amazon prime member its free shipping and environmental fees are waived.

XSpower sells a deep cycle marine that is decent at 145Ah for $365 on amazon .com free shipping and environmental fees are waived if you are a prime member.

I would also look into Concorde Batteries

There are a few stores selling them for $125 for the 100Ah batteries but you have to look around and search for them on bing.

XS power and VMAX tanks are chinese batteries, if you are all american I would go with the concorde battery.

niel

Re: Deep Cycle PV and Camping

while it will be hard to say if what you will get will be sufficient or not you can certainly try it. we can't say if the cc you propose will work or not either as going cheap isn't always going wisely. with no guarantees that you won't need to revamp what you have then the risk is yours to try and obviously by how you are talking you must try something soon.

SolarPowered

Re: Deep Cycle PV and Camping

niel wrote: »

while it will be hard to say if what you will get will be sufficient or not you can certainly try it. we can't say if the cc you propose will work or not either as going cheap isn't always going wisely. with no guarantees that you won't need to revamp what you have then the risk is yours to try and obviously by how you are talking you must try something soon.

SunForce for being a "cheap" inexpensive controller is pretty durable.
I typically follow amazon reviews in the product comments section. I'll contact the comment reviewers for their experience and how long they potentially have owned the unit for.

The 8amp unit that Nountaineer purchased is actually better than the 10amp controller I recommended. Reason being that the 8amp pro bussing will accept 10AWG USE-2 while the 10amp I recommended which can handle up to 12 amps digitally controlled with mosfets has 12AWG hard wired into the controller for input/output which some what limits voltage drop.

The 10 amp digitals I have purchased have run strong for over a year with no complications. Amazon comment reviews for the 10 amp digital/mosfet controlled are at 4 out of 5 stars (47 comment reviews total), the 8 amp SunForce pro has a 4.5star out of 5 rating (3 comment reviews total) and is only $10 more than the 10amp digitals I purchase. They are well worth the investment and the biggest bang for the buck.
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Nountaineer

Re: Deep Cycle PV and Camping

niel wrote: »

while it will be hard to say if what you will get will be sufficient or not you can certainly try it. we can't say if the cc you propose will work or not either as going cheap isn't always going wisely. with no guarantees that you won't need to revamp what you have then the risk is yours to try and obviously by how you are talking you must try something soon.

Neil, Would you suggest that I add the additional 45 watts (30watt+15 watt) to the Xantrex 35 amp controller which is under-loaded with only 2-100 watt PV panels, saving the "inexpensive" Sunforce Pro 8 amp as an emergency back-up or split the load between 2 controllers as SolarPowered has advised?

niel

Re: Deep Cycle PV and Camping

if running more than 2 pvs in parallel the pvs will all need fused. you could do the parallel arrangement if you like with fusing if the voltages of all of the pvs are not too far off from one another. i recommend within 5% and others say up to 10%.

you could save yourself some trouble and just make a separate pv system with the smaller pvs feeding the other cc in addition to the 200w in pvs feeding the sunsaver and have these both go to the battery, but a fuse near the battery for both pv systems. your call.