maybe I'm dumb

[wannabelikeward]

Hey, I have a line on 6 13W panels for $425 CDN.  I think it is a good deal, as stores up here sell 15W panels for $169 each. The guy says I can connect them in series to increase my output. Is this true??   Also, can I use an old large farm tractor 12V batt for storage??  I hope I don't annoy any old pros out there with my newbie questions.  I will be living in the bush in my tent for 4 months this summer and want to create a small, cheap system for lighting and a few small appliances.  My motivation for this line of questioning was "Ward's Cheap Solar Power System" . Thank you.

[asheets]

The question is:  do you want more amps or more volts?  Wire them parallel for the former (+ to +, - to -), or series for the latter (+ to -).

[kurt]

if they are 12v panels then you need to wire them in parallel for more power at 12v + to + and - to - . as for the tractor battery it won't last very long deep discharging it be better off with a  deep cycle battery  don't know what you are planning on running but 6 13w panels will only make about 30 amp hours at 12v per day on nice sunny days much less than that on cloudy days. enough to run a cfl light for a few hours and maybe a radio.  

[asheets]

Oh, and yes you're getting a decent deal, because it works out to about USD$4.50/watt.

[wannabelikeward]

 I will make sure the panels I get are a good quality so I can incorporate them into a higher quality camping type system later.  With your advice, I will probably look into finding a nice used 6V golf cart batt ( 4 of them).  I have done alot of surfin for those batts, can't find any under 200?!  In wards system it is stated that a BP 75W panel is used.  If I connect these 6 13W panels, will I not generate 78W output??? And, as for voltage, I do not understamd that part yet, still learning.   What do you figure???  

[wannabelikeward]

Thanks for the comments so far everyone. Just so you all know I am not trying to be lazy and just ask how to do it, I have been surfin for 2 days straight ( work is slow right now!! ), I just want to take all my findings and all the muchly appreciated free advice and put it all together to come to the best conclusion and system!

[wannabelikeward]

how is 6 13W panels wired together different than 1 @ 75W???  Also, I am a pretty good back yard electrician, but I am not very schooled on the technical stuff, volts, amps, etc.  I am going to take a multimeter with me when i look at these panels that i might buy, but I don't know what setting to put it on?  Do I test for voltage output, wattage output, or what???

[Hank]

Six 13 watt panels wired in parallel will be similar to a 75 watt panel.

Make sure they are for a 12 volt system.

The open voltage for a 12 volt panel should be in the range of about 19-21 volts in full sun.

Set your volt meter to DC volts and make sure the range setting is correct then attach your leads to the wires from the solar panel put it in the sun and read the out put.

You could measure the amperage if and only if your meter has a 10 amp setting. In this case set your meter to 10 amp setting and read as above, this will give you the short circuit current (amps).

A 13 watt panel shold give you about 1 amp ( probably a bit less).

[wannabelikeward]

thanks a lot Hank, wicked awesome advice.  I do know they are 12V panels.  So, if I connect them in parallel and then connect to a charge controller and then to the batts, I should have a system??  Do you know if a simple 7 Amp controller will work? Canadian Tire sells one for $29.  Can I wire a guage inline to tell me battery state of charge, if so, what type (measure: would be amps, volts, watts??) Would I put a guage on the line into the batts, or the one out to 12v appliances or online before inverter?? Or does it matter?

[ghurd]

By `The Bush", do you mean fly-in?  Have you done a long term fly-in before?

Efficiency is what the question should be about.  I think.

Good quality PVs are heavy.  If I needed that much power on a fly-in, I would buy light weight `disposable' PVs.  Like HF POVs.  Good PVs take less area but are heavy.

Max-weight is a lot less than you may think.  The machete isn't needed if there is an ax at the base camp.  4 guys don't need 4 fillet knives or 4000 band aides.

There will be plenty of time to carry water. Save the battery power for something else. Maybe a Sat-phone?

"Also, can I use an old large farm tractor 12V batt for storage"

A `tractor battery' has got to be too heavy.  I can not see a single 85AH battery being too small.

We take a 7AH and a couple dozen AAs. No inverter. No AC stuff.  It would not fit in the plane anyway.

Around day #10 most people would wish they had more Pepsi, beer or 100% DEET.

Not sure what you mean by `a few small appliances'.

If it is not propane or AA powered, you need to look for another system.

"I will be living in the bush in my tent for 4 months".

I am guessing Canada.  "tent' and `4 months' in the same sentence means black flies.  No matter what the guides said. The guide's perception of `bad bugs' is far different than yours.

There is no such thing as too much DEET, or too many PIC coils, or too many Bic lighters.

Anything under "90%" DEET is a joke.  Pumps only, instead of sprays. Only pumps (ie muskol).  We figure 1 oz 100% pump bottle per 2 persons per day. "Bug Season" figure 2oz per person per day.  God forbid we ever run out in May, June or September.

Coils are the only thing for black flies in an enclosure.  "Yard-Guard" in a place like these is a waste of effort, weight and money.

A Bic can save your life.

End Lecture.  :-)

Do not take 4 months in the bush lightly.

A link that may give you an idea what I mean...

http://www.fieldlines.com/story/2005/8/21/205627/022

G-

[Hank]

In your case a simple 7 amp controler will work fine, I have used one for quite some time with no problems.

As far as "state of charge" perhaps the simplest and cheapest way is to measure battery voltage. This is not the best way but is a good indicator.

Here is a site with some good battery info:

http://www.uuhome.de/william.darden/carfaq4.htm#index

Just be aware that you will not have a whole lot of power at your disposal with this system so conservation is a must.

Good luck!

[wannabelikeward]

Thanks for the info Ghurd.  Its not as bad as all that, or as remote. I am going to be on the eastern slopes of the Rocky Mountains in Alberta.  I will be an hour from a small store, etc.  I have a quad to get all my gear in and I am doing it for no other reason than to live a simple, laid back summer.  There aren't really any black flies around here. They are further up north in the Northwest Territories, Yukon, etc.  Around here we have bad mosquito seasons every now and then, but that's it.  Thanks again.

[wannabelikeward]

Thanks Hank.  I think I am well underway. Now I just have to get all the gear, set it up and try it out. Hopefully I don't fry anything!!!  

[AbyssUnderground]

My 90Ah SLA is 28KG! Good luck trying to carry something that heavy.

[asheets]

watts = voltage * amperage

To increase voltage, wire all the panels in series

To increase amerage, wire all the panels in parallel.

Therefore, assuming that 1 panel produces 13W at 12Volts, your amperage is 1.08A.  If wired in parallel, you'd have 6.48A at 12V, for a total of 78W.  If wired in series, youd have 72V at 1.08A for a total of 78W.

But, if you're charging 6V batteries, you'll be wasting a bunch of those watts with either voltage regulation or voltage pulldown prior to full charge.

[wannabelikeward]

So is one way more optimum for a faster, better charge.  For the system I will run 1 CF light, maybe 2, on occasion a radio and small TV. And daily I will run a small water pump (10 min. a day) for showers. I will try to find the smallest, least power consuming pump I can.  Will 75W +/- and 1 or 2 12V batts be enough? Is 1 or 2 12V batts better than 4 6V batts??  With a few hours of use each day, will it be able to recharge by the evening of the next day ( in good conditions)?  

[ghurd]

I think the amps will be a little less, more like 0.75A per panel.

A 105AH 12V should be fine. Choose the TV carefully. A radio isn't much power.

Pumps.  I like the Attwood V-series.  Cheap, small, light weight, and very efficient.

The head is not a lot.  Showering near the river (bio friendly soap) will need less hose and head.

The head drops quickly when the battery is lower than 13.0V, but I rarely care to take a shower in the bush unless the sun it shining, so the battery voltage should be OK.

I would go with the V900 for 3' more lift.  2nd choice, the V500.

(the V625 looses good flow above 4' or with a long hose, the V750 isn't what the V900 is, and the V1250 is large and expensive)

Some Wally-World's carry them at a Very good price.

Wrap the pump in nylon window screen.  Long nasty story about that involving freshly ground... uhm, well... we think they were minnows.

G-

[wannabelikeward]

Thanks Ghurd, you are a fountain of knowledge!!  A little fish guts is probably good for the skin, you may be onto something there!!  

[ghurd]

Except it was in the coffee!  Scales looked like glitter, after we noticed them.

http://www.attwoodmarine.com/products/pumps/v_pump_charts.asp

[wannabelikeward]

hahahahahahaha, ahhhh camping!!!