Build a solar pv system to power this little lot??

Pete_M · Post by **Pete_M** » 06 May 2007, 13:00

Tess,
Maybe you should think about a yacht instead of a narrow boat. The cost
of the propulsion system you seem to need plus the capital for the narrow boat would pobably buy you a decent live aboard. Of course you would have to be based on the coast. Then you can go where you like without any fuel.
Heating would be a problem though.

Pete M

RevdTess · Post by **RevdTess** » 06 May 2007, 13:06

Pete_M wrote:Tess,
Maybe you should think about a yacht instead of a narrow boat. The cost
of the propulsion system you seem to need plus the capital for the narrow boat would pobably buy you a decent live aboard. Of course you would have to be based on the coast. Then you can go where you like without any fuel.
Heating would be a problem though.

Pete M

I'd love to do both

The inland waterways community is awesome though. Wouldnt want to give that up.

Bandidoz · Post by **Bandidoz** » 07 May 2007, 23:10

Instead of a horse, or PV with a ton of batteries, would it not be possible to run your motor from WVO?

Perhaps narrowboat-tugging could become a new fitness craze (a sort of "green gym")

Ippoippo · Post by **Ippoippo** » 22 May 2007, 14:26

Hi All.

This thread has been pretty interesting to read. Must admit, my physics is a bit rusty since A-Level's back in '95.

Apologies, long post ahead

I've been trying to work out what I need (not just the Panels, but all the other stuff, battery's, controllers etc). The bit I find hard is understanding what things would be compatible with what.

Anyway, my objective is as follows. Currently in rented accomodation, and the place we are in may be a short term measure. I'm trying to get a little further up into the hills (currently, right on the outskirts of Cardiff, but still in a residential housing area). I want to move out a little into the country to get away from prying eyes to help a little in the SHTF scenario. Hopefully won't come to that.
Nonetheless, for now this is where we are.
So, I want to get some Solar generation in to provide some power. I wouldn't be intending for this kit to wired into the house, but to charge up batteries and feed our stuff of that where possible. I guess the panels would need to go out into the garden instead, though I'm concerned about how much light they'll get plus being visible to neighbours. Keeping them indoors in front of the south facing window would be great, apart from how much sunlight you'd get!
I've been going through our 'electrical' inventory for stuff we own and would come with us to a new home.

MacBookPro (which is our TV as well). The power adapter for this is rated as 85W (it also says 100V-240V 1.5A input, 18.V 4.6A and 16.5V 3.6A output). It would be good to get this powered off-grid. Average usage during the week would be 2 hours a day for TV, plus my missus uses it 3 hours or so during the day. Weekend sees about 6 hours usage.

External Hard Disk. Power adapter is rated as 100V-240V 1.2A input, 12V 3A output. [It also said 70VA on it, so in other words, 70W. How they hell does that tally with the V and A figures for the Input and output???] Average usage would be 5 hours per week.

External DVD writer. Requires DC5V 1.5A or DC12V 1.0A according to the sticker on it. Usage... hardly ever, only if watching a Region 1 DVD on the Mac.

Printer. This is a Japanese device. 100V input. According to the manual, it's 22W for 'Copying', 'Sleep' is 2W and 'Off' is 0.8W (0.8W for when it's OFF!!! What the hell is it doing!!! Off for me is 0W, unplugged!! ). Usage would be maybe about 1 hour a week at most, probably less.

Multi-region DVD Portable Player - 100V-240V Input, DC12V 2.0A output. Average usage. If I ever want to watch a DVD by myself, I can cope with watching on this rather than the Mac to keep power consumption down.

The only other 'consumer goods' would be a PSP (charger is rated as 100V-240V, 0.3A input, 5V 2000ma output), and two mobile phones/charge (Nokia N73).

So, out of that lot, really, it's the MacBookPro and the External HDD which would consume the most power.

In terms of kitchen equipment, I guess the two rather useful items are...

Microwave, 1200W (800W output). Assume 30 minutes a day at the most.

Hotplate (from Japan), which can be used for stews, frying etc). That's rated at 1350W (and is 100V input). Assume 30 minutes a day at most.

If we lost gas, those would be two pieces of equipment we could use alone to cook most stuff (plus the barbeque!).

Other 'handy' equipment in decreasing usefulness level would be

Kettle 230/240V input, 13A Max. Can't find how many Watts, since this was a freebie from my parents.

Rice Cooker. Japanese. 100V 1200W (has 20A internal fuse).

Blender. Japanese. 100V 220W

Juicer. Japanese. 100V 170W.

As you can see, we have some Japanese kit, which we run through either a 3000W transformer (has two 1500W output sockets), and 1500W transformer (two 750W outputs). Now, of course, I'm aware of effiency loss in running 240V down to 100V.
So, if I was going to rig up the Japanese stuff, presumable it would be better to get output from the battery up to 100V, rather than 240V and back down to 100V.

So, if I wanted to run the MacBookPro, HDD, Microwave, and Hotplate what kind of kit would I need (following a previous worked example in the thread)...
Assume
MBP, 6 Hours, (85/1000)*6=0.51kWh
HDD, 1 Hour, ((12V*3A DC input)/1000)*1=0.036kWh
Microwave, 0.5Hour, (1200/1000)*0.5=0.6kWh
Hotplate, 0.5Hour, (1350/1000)*0.5=0.675kWh

Total kWh is 1.821, requiring 1821/12=151Ah batteries. Assume 60% discharge.. 300Ah ish

So, now, I'm a little lost as to work out what bits of equipment I need to support that lot???? Anybody got any thoughts on this??

Post by **kenneal - lagger** » 22 May 2007, 17:25

You need an inverter that can cope with your peak load and batteries that can store twice your daily total supply( to allow for 50% depth of discharge). Your PV panels must be enough to keep the batteries charged given their siting, shading and orientation.

Regarding your loading, I would say don't do any major electric cooking or water heating. It's too expensive in PV and batteries. You haven't allowed for lighting, ventilation fans or central heating pumps.

Ippoippo · Post by **Ippoippo** » 23 May 2007, 10:12

kenneal wrote:You need an inverter that can cope with your peak load and batteries that can store twice your daily total supply( to allow for 50% depth of discharge). Your PV panels must be enough to keep the batteries charged given their siting, shading and orientation.

Sure. I think I can work through the stuff that Mike P and others have done to work that out.

kenneal wrote: Regarding your loading, I would say don't do any major electric cooking or water heating. It's too expensive in PV and batteries. You haven't allowed for lighting, ventilation fans or central heating pumps.

Hmmm. I understand what you are saying. It's an interesting problem though. I don't want to get into debt by buying a home, which I could then fit with with a wood burner/range for cooking (and heating). Yet, doing that is the 'optimum solution'.
If you are stuck renting, then unless you get lucky and rent in a place which has a wood burner/range, and allows cooking by non-gas (or main-electric), you have a problem

Hence looking at options for using cooking tools I already have.

Lighting I figure is less of a problem. We only ever have 1 light on at once at home (except for the odd toilet trip, and bathtime). Some form of basic solar camping light would be fine.

Where's the best place to get some of this kit from? I've seen people on this thread using eBay. Must admit, I'm a bit wary of eBay, but you can get cheaper prices though. (Some of those 'kits' I've seen on other sites seem expensive).

Anyone have any thoughts on the 100V AC input issue for some of the kit?

Bandidoz · Post by **Bandidoz** » 23 May 2007, 16:35

GavinT wrote:Anyone have any thoughts on the 100V AC input issue for some of the kit?

Transformer?

Ippoippo · Post by **Ippoippo** » 23 May 2007, 16:59

Bandidoz wrote:
GavinT wrote:Anyone have any thoughts on the 100V AC input issue for some of the kit?
Transformer?

Already have 240V->100V ones (as mentioned back a couple of posts).
My thoughts are, surely more efficient to go 12V DC -> 100V AC, rather 12V -> 240V AC, and then use a transformer to get back down to 100V.

........ unless of course you meant, use a transformer to do '12V DC -> 100V AC'.

Just wondering where the hell to get such a contraption

Post by **kenneal - lagger** » 23 May 2007, 17:20

GavinT wrote: Where's the best place to get some of this kit from?

Try http://www.navitron.org.uk/

Bandidoz · Post by **Bandidoz** » 24 May 2007, 01:11

GavinT wrote: My thoughts are, surely more efficient to go 12V DC -> 100V AC, rather 12V -> 240V AC, and then use a transformer to get back down to 100V.

You're talking about 3% loss. Don't lose sleep over it. Especially when you're not dealing in GW. And the MTBF is probably much better as well.