Solar panels, 12v cool box, no battery charger..... Advice please.

[McLosi]

Hi everyone, hope all are well.
So appears my 97 Elddis Alfresco doesn't have a charging unit. I assume it's previous owner removed it for some unknown reason.
So my question...

If I purchase this - https://smile.amazon.co.uk/dp/B016OP9WBC/ref=cm_sw_r_cp_apa_i_lJnnFbN9PN05C

Do I simply use croc clips from the unit and that will charge the battery when the panels are out?

Then my other part to this question is I have a 12v/230v cooler box. If I am not on electrical hookup, had the panels connected to the battery, could I then use one of these
https://www.ebay.co.uk/itm/353160948662 connected to the battery to keep the box cool but also the battery carry on being charged from the panels...
I guess I'm worried the cooler box will try and take power direct from the panels if that is possible?

Thanks for your time.

 

[JTQ]

Whilst a very qualified "yes" to both questions it should be noted that a 10 Watt solar panel is way too low a power rating to be of any constructive use.

We need to know the power drain of that cool box to tender any worthwhile advice, but I feel a very much bigger panel is going to be required, and even that is going to be only viable through the main season where we could have plenty of sun energy to tap into.

 

[McLosi]

Whilst a very qualified "yes" to both questions it should be noted that a 10 Watt solar panel is way too low a power rating to be of any constructive use.

We need to know the power drain of that cool box to tender any worthwhile advice, but I feel a very much bigger panel is going to be required, and even that is going to be only viable through the main season where we could have plenty of sun energy to tap into.

Thanks, the link should be for the 50W one.

Wheels N Bits 22 Litre 12 Volt Cooler box Ice For Camping Caravan Motor Home Car Van Truck Power ABs Box with lid : Amazon.co.uk: Automotive

Shop at Amazon.co.uk for Wheels N Bits 22 Litre 12 Volt Cooler box Ice For Camping Caravan Motor Home Car Van Truck Power ABs Box with lid : Automotive.

smile.amazon.co.uk

This is the cool box, does t give power ratings.

Would the 50W panel help keep the battery charged instead of buying and connecting a separate charger?

 

[RogerL]

Our old cool box is 48W so draws 4 amps - modern ones could well be more.

A 50w solar panel won't deliver anything like 50w as an average over the 24 hour period a cool box needs to run.

 

[JTQ]

Sorry but without some understanding of the power consumption and how the cool box behaves in drawing power, eg how often it comes on load, I can't begin to make any predictions other than "gut feel".
I would have thought the box would have had a makers plate indicating its Wattage, or at least its mains adaptor would?
Then there is the question of how frequently it draws power, this will depend on where it is located, ambeint and set temperature.

Looking at things from the other end you can expect a solar panel might average up to a third of its rating for 8 hours a day. Given thatcrude rule of the thumb the 50 Watt version. That gives 133 Watt hours, equating to 11 Ah of energy available each day. So if the cool box only uses 5.5 Watts on avarage throughout the whole 24 hours it would work.
The "gut feel" is it will take a fair bit more and a 50 Watt solar system will not cope.
On the general point re solar; these are now so cheap compared to what they once were and even a 100 watt size is still physically managable, that if buying into solar it becomes somewhat counter productive to penny pinch. Therefore don't and so buy a 100 rather than a 50 Watt.

Roger's contribution endorses my gut feel, you have no chance of consistently operating a decent size Peltier effect technology cool box off solar, even if buying a 100 Watt panel

 

[McLosi]

Sorry but without some understanding of the power consumption and how the cool box behaves in drawing power, eg how often it comes on load, I can't begin to make any predictions other than "gut feel".
I would have thought the box would have had a makers plate indicating its Wattage, or at least its mains adaptor would?
Then there is the question of how frequently it draws power, this will depend on where it is located, ambeint and set temperature.

Looking at things from the other end you can expect a solar panel might average up to a third of its rating for 8 hours a day. Given thatcrude rule of the thumb the 50 Watt version. That gives 133 Watt hours, equating to 11 Ah of energy available each day. So if the cool box only uses 5.5 Watts on avarage throughout the whole 24 hours it would work.
The "gut feel" is it will take a fair bit more and a 50 Watt solar system will not cope.
On the general point re solar; these are now so cheap compared to what they once were and even a 100 watt size is still physically managable, that if buying into solar it becomes somewhat counter productive to penny pinch. Therefore don't and so buy a 100 rather than a 50 Watt.

Roger's contribution endorses my gut feel, you have no chance of consistently operating a decent size cool box off solar, even if buying a 100 Watt panel

Thanks for that, makes sense and agree will opt for a 100w instead.

Re my question about just clipping it all on the battery, is that correct?

 

[JTQ]

Thanks for that, makes sense and agree will opt for a 100w instead.

Re my question about just clipping it all on the battery, is that correct?

Yes that will work but I don't like it being un-fused so needs real care in use, however even with a 100 Watt solar panel your battery is doomed to be flatted quickly running a cool box from it.

 

[Guzzilazz]

The cool box is a Peltier effect (thermoelectric) cooler. These devices on 12 V typically draw 5 amps continuous... A 100 W panel will at best deliver an amp or two (no matter what the BS says in the spec) - my observations are with my panels on my boat which I've had for 11 years. If you had a compressor cool box (much more expensive unfortunately) you could cope. We were able to operate the cool box off grid for about a week with 90W panels. Because the compressor switches on and off thermostatically, although it draws 5A, it runs for about 10 minutes per hour so averages at 0.8A continuous

 

[ProfJohnL]

I have to agree with Guzzilass and JTQ, the idea of trying to run a peltier coolbox with a battery and a 50 or even 100W solar panel is most likely to fail.

I would also add that most of these 12V cool boxes have a rather annoying fan noise, and would probably becoming very annoying if running inside the caravan at night.

 

[McLosi]

Ok thank you. I wasn't planning on running the cool box for great long periods of time when off grid, just a day or 2, for example this weekend I am camping one night without hook up and wanted to know if having the Solar panel would help keep the battery topped up for longer and that I wasn't going to do any damage.
I understand I wouldnt be able to run the cool box for great lengths of times off the battery which is fine with me. It would mostly be sat in the awning on the 230v power when we have hook up and just on the odd occasion that we dont I would use the 12V

 

[Guzzilazz]

If you run the coolbox AND ABSOLUTELY NOTHING ELSE your fully charged battery will be ok for 10 hours (you should only discharge a battery to 50% to prevent damage to the battery, assuming a 100AH battery)

 

[JTQ]

Which is also assuming the battery is in its early youth and has a capacity somewhere near its labelled value, not a battery with any aging already reducing its capacity or one with optimistic labelling from new!

 

[ProfJohnL]

Most peltier cool boxes are not practical fridges. They have a rather limited cooling ability;- poor ones might manage 5C below ambient and the very best might manage 20C below in optimum conditions.

Most are really just glorified cool boxes, and they're not helped by the comparatively poor insulation these boxes tend to have.

Functionally are best used to help keep pre chilled goods cool, as they struggle to cool down warm goods.

Consequently these boxes need to run continuously, rather than be used intermittently.

There is little point in just running one of these peltier cool boxes for just a few hours, unless the contents is already chilled.

If weight is not a real problem, then there are more serious stand alone portable 3 way powered absorption fridges. These run on exactly the same principle as most caravan fridges, these are designed for camping. Their far more efficient that peltier coolers and are virtually silent. Some even can be powered from a gas cartridge for a few hours.

 

[McLosi]

Where do I find these? Or what should I search please?

 

[JTQ]

This is the modern version of one we have back from our tent camping days,

Dometic RC1200 3 Way Camping Fridge LPG 12v Mains

The Dometic RRC1200 3 Way Portable Camping Fridge can be used on 12v in your vehicle, 230v on the campsite & on LPG gas in remote areas! Ample capacity & stylish cabinet, sent on a Next Working Day delivery!

www.jacksonsleisure.com

Again whilst it has a 12 volt option that is totally unsuitable for use from a battery, it is for use during travelling when the alternator is able to feed the 7 odd amps I think its heater element draws.
Our is very effective on Propane.
The only sensible use when on gas caravanning is within an awning or similar, good ventilation and out of the rain.
Ours on gas only requires a gas supply, no 12 VDC control system support, hopefully modern ones retain that simplicity.

 

[McLosi]

This is the modern version of one we have back from our tent camping days,

Dometic RC1200 3 Way Camping Fridge LPG 12v Mains

The Dometic RRC1200 3 Way Portable Camping Fridge can be used on 12v in your vehicle, 230v on the campsite & on LPG gas in remote areas! Ample capacity & stylish cabinet, sent on a Next Working Day delivery!

www.jacksonsleisure.com

Again whilst it has a 12 volt option that is totally unsuitable for use from a battery, it is for use during travelling when the alternator is able to feed the 7 odd amps I think its heater element draws.
Our is very effective on Propane.
The only sensible use when on gas caravanning is within an awning or similar, good ventilation and out of the rain.

Fantastic thank you.

 

[ProfJohnL]

You might find this article of use:-

Best Camping Fridges And Coolbox – Our Fridge & Coolboxes Guide | Campfire Magazine

Which camping fridge or coolbox should you buy? We test a range of compressor, thermoelectric and passive, unpowered coolers to help you choose.

campfiremag.co.uk

On a related page there is some information about running a compressor fridge on solar

Power For Campers – Hook-up, Solar Power And Portable Power | Campfire Magazine

The best ways to power your gear when camping or in the campervan? Solar power for phones? Hook-up for the fridge? We look at the options for camping power.

campfiremag.co.uk

 

[McLosi]

You might find this article of use:-

Best Camping Fridges And Coolbox – Our Fridge & Coolboxes Guide | Campfire Magazine

Which camping fridge or coolbox should you buy? We test a range of compressor, thermoelectric and passive, unpowered coolers to help you choose.

campfiremag.co.uk

On a related page there is some information about running a compressor fridge on solar

Power For Campers – Hook-up, Solar Power And Portable Power | Campfire Magazine

The best ways to power your gear when camping or in the campervan? Solar power for phones? Hook-up for the fridge? We look at the options for camping power.

campfiremag.co.uk

Oh wow thank you. So much to learn lol

 

[Buckman]

We had the absorption cooler and it was brilliant. It could keep food frozen for weeks or months. Also very quiet. Ours was the Waeco before it became the Dometic. As we were on a seasonal site no issues lugging it around, but when we started touring again, okay if you were going away for 2 - 3 weeks, but its size took up a lot of room in the back of the vehicle. We sold it a few years ago and althouhg not a fan of Halfordds bought a Halfords coolbox which proved to be very reliable however again we found it took up too much room in the rear fo the vehicle. In hindsight we should have bought the smaller one. The Halfords one is now sitting in our garage and need to sell it sometime.