Safe Speed Forums

With some cash from my Mum's estate, I've purchased a couple of 'high power' solar panels for my campervan. They produce a theoretical 80W each in full sunlight. Something like 5 amps at 14V each making 10A total assuming full bright sunlight.

That's going to be great while I'm working away from home. It'll mean that on a sunny day I can run the usual stuff (TV, laptop, fridge) straight off the sunlight and still be putting charge into the batteries.

But most of the time the batteries are going to be full and the 'free energy' is just going to be completely wasted. The engineer in me is as annoyed as hell about that! So I'm wondering what I could possibly do with the solar panel power when the batteries are full.

The best I've come up with so far is to run a Peltier based dehumidifier.

Wacky ideas about making hydrogen and accelerating large flywheels have been dismissed as not very practical.

Heating water is obviously possible...

Any good ideas?

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

fair few people playing around with hydrogen for cars....if you can produce it without a hindenburg side effect it (in theory) could reduce fuel consumption

think it only works on modern vehicles with computer controlled fuel injection that senses the extra fuel in the mixture and leans of the petrol

not entirely sure though i would want to attach anything generating a highly imflammable gas in my engine bay

how about installing proper air con for the er hot sunny weather we are expiriencing

Heating is probably the easiest thing.

Connect a coffee maker? If you like coffee, obviously.

Turn the laptop on and run SETI (or similar)?

Make an electric chair and rent it out?

Do a deal with a mobile phone company and become a portable cell site repeater?

Turn the van into a hot air balloon and use the electricity to power the heaters?

Use electrical heat to create food stuffs which you can sell?

Run a pirate radio station?

Get a tanning bed and rent it out?

Or get a bigger battery...

Would a dehumidifier provide you with clean water to drink? Not a lot I'm sure, but still some. I mean, is it clean enough to drink? Or wash with? Or something?

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Andrew.

I have to say I find the idea of using solar power to drive an air-con unit very appealling, in the same vein as using a heatpump to take the heat out of the ground outside and heat your home, even when there's a foot of snow on it!

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Ticketo ergo sum : I scam therefore I am!

Yeah, I'd love proper aircon - and I've been looking at it. Domestic air con is quite cheap, but the roof-mount campervan air cons start at about £700 - and they need around a KW to run - that's four grand's worth of solar cells, and probably considerably more than a roof-full. So they only run in practice with mains hook-up or a generator. I've got a nice little generator, but it's a bit too noisy for the places I end up working, and not really enough power for an air con.

Another technical solution to running air con is to connect a 1.5KW mains voltage alternator to the engine. For 50Hz you need a shaft speed of 3000rpm on the alternator, so maybe the engine could be persuaded to idle at 1000rpm with a 3:1 pulley/belt arrangement from the crank. In truth it's likely to be too hard and/or too expensive.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

I'll have 330Ah, but you need to run lead-acid batteriers fairly full most of the time in order to look after them. I'll be able to charge them by solar, by generator, by mains hook-up or by engine. Having a bigger battery doesn't help much...



Yeah, clean enough to drink, certainly, so long as suitable materials were used in the dehumidifier, and the dehumidifier was kept clean. Nice touch!

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

This is interesting:

A fridge that fits with a 'cold accumulator':

http://www.waeco.co.uk/shop/details.asp ... &i=&p=1627



So when the batteries are full the right control electronics could use the solar power - or some of it - to ensure that the 'cold accumulator' was fully charged, thus saving the batteries from having to run the fridge overnight on hotter longer days.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

i think we can all see where you're going with this one

Unfortunately, you are likely to be disappointed by the actual output you will get averaged out over a day in the UK. On a very clear day in summer you might get the 5A rating for 1 hour per day. The rest of the time will be very much less. Averaged over the 16 daylight hours in high summer you will probably get 2A x 16hrs = 32Ah at 14V for charging. In the winter the average output will be about 25% of the above as you have weaker sun and only 8 Hrs of light. Your 330Ah battery array will need continuous overcharge of about 1 to 1.5A to keep it healthy anyway after full charge so you won't have a lot of spare energy.

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Malcolm W.
The views expressed in this post are personal opinions and do not represent the views of Safespeed.

I read somewhere, or maybe I've just made it up, that you ought to be able to connect power to the national grid and get money back.

I imagine it's not a simple as connecting two croc clips to the overhead cables and doubtless there are legal restrictions to messing with someone elses property.

I feel the need for a disclaimer here, just in case someone tries it

Sounds like a good idea in principal though eh?

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

I'm an engineer of muck and concrete but I reckon

a fridge/aircon dehumidifier combo. When the sun shines you need to keep cool and what better than to use the source of your discomfort as the source of the remedy?

A fridge and aircon unit are effectively the same things, and the dehumidifier....i'll leave that to you!!

Yeah, I'm fully aware, altough they are already doing rather better than you suggest. The theoretical capacity (160w) is 2.5 times the planned requirement (60w). And I'm quite used to managing battery power.

I'll report back about how well they are doing when I have some more experience (they aren't mounted on the campervan yet).

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Do my eyes deceive me. Is Paul going green and trying to reduce global warming and save the planet.

It may have been more energy efficient and more cost effective to put the money to a new more economical camper van.

Power could be used for providing hot water (in well insulated storage) and storage heating (for when stationary), but they take LOTS of power.

Cooling fans for the summer may be useful.

When you can connect to a mains electric supply, you could sell it back to the electricity suppliers.

Uh? Am I invisible? I'm sure I just said that

I'm hurt. Nobody loves me Goodbye cruel world...

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

Nah. Photovoltaics aren't 'green' I suspect that making them consumed more energy than they will ever produce.



There just isn't enough cash to change the vehicle. Anyway this isn't even remotely about saving energy. It's really about availability of power. Quite often I've had to do without TV and fridge bacause there wasn't enough battery power. The TV's quite important for rolling news.



Yeah. Although there's no hot water in the campervan (except the kettle of course) I don't really miss it. I'm happy to wash in cold water and when I boil the kettle the left-over hot water does the washing up.



Yeah, although you would need a vast fixed solar array to give enough to the grid to payback the cost of the grid-tie interface itself.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Don't take on so... great minds and all that.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Aquire a fridge.
Fit fridge to rear door of camper van so that the hot side of the circuit dumps outside through an orifice ( fancy word fo hole eh?).
Inside campervan, remove fridge door.
Run fridge off of inverter powered by solar cells.
Camper gets cool as, storage for beers is still available, heat form camper gets dumped outside.....
Add a fan inside the fridge and i think itd work even better....
Its gonna look a little MadMax tho.

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"Safety" Scamera Partnerships;
Profitting from death and misery since 1993.

Believe nothing- Question everything.

You do?
I was thinking of ways to use the energy to make money. Money is good, right?

I was going to suggest selling the electricity to the national grid but I guess the reason for this whole thing is due to there not being any national grid anywhere near...

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Andrew.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

The top end merc has some sort of solar powered aircon setup, so there must be a low power solution.

Regarding mains power, an easier/more conventional way to do it would be to uprate the standard alternater & fit a high capacity/2nd battery & inverter, with solar cells could topping up the battery constantly. This would also give silent running...

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Fear is a weapon of mass distraction