Solar power anyone

Casey and I had a conversation today about how to run things off batteries from solar panels. I'm guessing someone who knows what the hell they are doing would either shoot us or themselves after reading this and finding all the incorrect hypotheses we came up with.

TheNatureBoy9 (8:57:22 AM): how much do you know about amps/ batteries/ watts/ solar panels things like that?

TheNatureBoy9 (8:57:31 AM): more specifically the math to determine how long it takes for things to charge?

caseyoman (8:57:56 AM): um, i know the sun powers solar panels

TheNatureBoy9 (8:58:01 AM): yeah i got that part

caseyoman (8:58:07 AM): truthfully, i haven't ever looked at it

caseyoman (8:58:13 AM): what specifically are you looking at,

caseyoman (8:58:19 AM): power for the car or for the water heater?

caseyoman (8:58:29 AM): did you get the link for the binoculars yesterday?

TheNatureBoy9 (8:58:31 AM): neither

TheNatureBoy9 (8:58:36 AM): just understanding of it all in general

TheNatureBoy9 (8:58:44 AM): maybe get a solar panel to play with for small projects

TheNatureBoy9 (8:58:59 AM): teach blake or the cub scouts some stuff

caseyoman (8:59:02 AM): there's a guy at work who talked about wiring up his 2002 prius to run w/ solar

caseyoman (8:59:08 AM): i'll ask him for some info

TheNatureBoy9 (8:59:10 AM): so i see a solar panel that is 40 watts

caseyoman (8:59:20 AM): ok

TheNatureBoy9 (8:59:23 AM): the current at max power is 2.48amps

TheNatureBoy9 (9:00:32 AM): if i have a UPS thats got a battery that is 220 watts / 350 VA how long will it take that solar panel to charge that battery

caseyoman (9:01:05 AM): VA is volt amp's?

TheNatureBoy9 (9:01:08 AM): i think

TheNatureBoy9 (9:01:19 AM): volt ampere rating

caseyoman (9:01:28 AM): http://en.wikipedia.org/wiki/Volt-ampere

caseyoman (9:01:29 AM): yeah

caseyoman (9:02:25 AM): isn't cory coming to the game?

TheNatureBoy9 (9:02:32 AM): yep

TheNatureBoy9 (9:02:33 AM): i may ask

TheNatureBoy9 (9:02:41 AM): surely theres a website i can find

caseyoman (9:02:44 AM): i would certainly

TheNatureBoy9 (9:02:45 AM): http://www.boatus.com/boattech/casey/30.htm

TheNatureBoy9 (9:02:46 AM): this might do it

caseyoman (9:03:30 AM): if it's like a science project, just rephrase the project

TheNatureBoy9 (9:03:36 AM): exactly

caseyoman (9:03:49 AM): "how long does it take to charge a battery with a 40 watt solar panel)

caseyoman (9:04:26 AM): hypothesis - 220 / 40 (5.5 hours?)

TheNatureBoy9 (9:04:58 AM): according to this

TheNatureBoy9 (9:05:03 AM): its 40 watts so divide by 15

TheNatureBoy9 (9:05:14 AM): gives you 2.67 amps

caseyoman (9:05:15 AM): so 2.6

TheNatureBoy9 (9:05:34 AM): * 5 hours of rated output per day gives you 13.3 amp hours from a 40 watt panel

caseyoman (9:05:54 AM): is that the rated output on the solar panels you have?

TheNatureBoy9 (9:06:23 AM): http://www.realgoods.com/product/solar+power/solar+electric/portable+solar/kyocera+40+watt+solar+pv+module.do

caseyoman (9:06:25 AM): plus it's only /15 at noon, so you are less effecient then advertised

TheNatureBoy9 (9:06:30 AM): this is what i was using as an example

TheNatureBoy9 (9:06:37 AM): 40 watts, 2.48amps max power

caseyoman (9:06:54 AM): cool

caseyoman (9:08:27 AM): so with 5 hours of daylight, you'd get about 13 amps

caseyoman (9:08:51 AM): so i think you'd be charging extremely fast

caseyoman (9:09:06 AM): 40/15 * 5

caseyoman (9:09:50 AM): so you'd charge the battery in less then an hour

caseyoman (9:10:02 AM): 2.48/(40/15)=.99

caseyoman (9:10:15 AM): assuming i'm reading the word problem correctly

caseyoman (9:10:38 AM): if it's just for a project, could you get a smaller solar cell?

TheNatureBoy9 (9:15:02 AM): yeah definately

TheNatureBoy9 (9:15:07 AM): just looking at this one for example sake

TheNatureBoy9 (9:15:12 AM): i dont think you would charge in an hour

TheNatureBoy9 (9:15:16 AM): the math is wrong somewhere there

TheNatureBoy9 (9:15:39 AM): you cant charge a battery in an hour if it takes 5 hours to get that daylight

TheNatureBoy9 (9:15:58 AM): i think that means you would get a max of 13 amp hours in a day

TheNatureBoy9 (9:16:19 AM): so it would take you 40/13=2.48 days to charge a 40amp battery

TheNatureBoy9 (9:17:29 AM): but to just top it off if you could leave it hooked up

TheNatureBoy9 (9:17:40 AM): it would constantly charge the battery and leave it topped off with no discharge

caseyoman (9:24:24 AM): i was thinking that the 40/15 was to handle the conversion to amps

caseyoman (9:24:59 AM): and the the 5 was to take care of the 12 hours of daylight

caseyoman (9:25:14 AM): so they're really only 5/12 max effecient

TheNatureBoy9 (9:25:27 AM): i guess

caseyoman (9:25:45 AM): so 13 in a day, like you said

TheNatureBoy9 (9:25:46 AM): that one site said expect 5 hours of good daylight of average per day

TheNatureBoy9 (9:25:49 AM): yep

caseyoman (9:25:58 AM): but 13 is way more then 2

TheNatureBoy9 (9:26:02 AM): true

TheNatureBoy9 (9:26:08 AM): but if you had a dead 40 amp battery

caseyoman (9:26:16 AM): yeah,

TheNatureBoy9 (9:26:16 AM): it would take 3 days to charge it

TheNatureBoy9 (9:26:20 AM): i think

caseyoman (9:26:26 AM): a dead 40 would take at least 3

caseyoman (9:26:38 AM): b/c the batter is discharging constantly a little

TheNatureBoy9 (9:26:57 AM): so i wonder how much your washing machine takes

caseyoman (9:27:13 AM): they're on a 220 right?

caseyoman (9:27:16 AM): or is that the dryer?

TheNatureBoy9 (9:27:22 AM): i know dryer is

TheNatureBoy9 (9:27:24 AM): not sure about washer

caseyoman (9:27:36 AM): i think my dryer is on a 110

caseyoman (9:27:45 AM): you thinking about going "off the grid)

caseyoman (9:28:07 AM): one of e's friends took a class on home design for that purpose

caseyoman (9:28:11 AM): from app state

TheNatureBoy9 (9:28:14 AM): no

TheNatureBoy9 (9:28:19 AM): no where near ready to off grid

caseyoman (9:28:24 AM): come on

TheNatureBoy9 (9:28:36 AM): solar panels need to improve efficiency

caseyoman (9:28:38 AM): you can be like the cdw guy on the island with the monkeys in those commercials

TheNatureBoy9 (9:28:45 AM): 16% efficient is bad

TheNatureBoy9 (9:29:01 AM): they get over 25% then it might be worth it, when payback is 5 years vs. 10-15

TheNatureBoy9 (9:29:15 AM): 15 year payback and 20 year warranties dont make much sense

caseyoman (9:29:15 AM): but it says "highly effecient:

caseyoman (9:30:17 AM): yeah, i've read about the "spray on solar" stuff

TheNatureBoy9 (9:30:24 AM): would be cool though to buy a battery that could handle an appliance

TheNatureBoy9 (9:30:30 AM): and just leave it hooked up to a solar panel all the time

TheNatureBoy9 (9:30:34 AM): do it yourself solar

caseyoman (9:30:39 AM): probably will work for our great grand kids

TheNatureBoy9 (9:30:44 AM): definately

caseyoman (9:30:54 AM): i've seen some people who have tons of daisy chained batteries

TheNatureBoy9 (9:31:10 AM): would be very cool

TheNatureBoy9 (9:31:17 AM): just buy really good deep cycle batteries

caseyoman (9:31:20 AM): the trick is to get them innitially charged and then get rid of all the vampires

TheNatureBoy9 (9:31:30 AM): yep

caseyoman (9:31:31 AM): ie no standby lights on dvrs,

caseyoman (9:31:41 AM): when it's off, make sure it is really really off

TheNatureBoy9 (9:31:42 AM): yeah

caseyoman (9:31:59 AM): there's some hippy commune in the mountains of nc like that

caseyoman (9:32:14 AM): read it in the washington post a while ago

TheNatureBoy9 (9:32:21 AM): i've begun plugging things into strips and turned off strips

TheNatureBoy9 (9:32:30 AM): but hard to do with DVRs

caseyoman (9:32:32 AM): but the guy was using insane amounts of energy (low amounts)

caseyoman (9:33:00 AM): http://www.washingtonpost.com/wp-dyn/content/article/2006/11/14/AR2006111400979.html

caseyoman (9:35:05 AM): skip to the section with this

caseyoman (9:35:17 AM): HE SUN WAS OUT, AND GREG GEIS WAS MAKING ENERGY.

caseyoman (9:35:32 AM): just do a search for it on this page

TheNatureBoy9 (9:35:42 AM): so i did some math

caseyoman (9:35:47 AM): ok

caseyoman (9:35:54 AM): what'd you come up w/

TheNatureBoy9 (9:35:55 AM): this one washing machine takes 197kwh per year to operate based on 8 loads a week

TheNatureBoy9 (9:36:02 AM): thats 473 watts per load

caseyoman (9:36:10 AM): ok

TheNatureBoy9 (9:36:14 AM): divide by 120 volts and you get 3.9 amp hours per load

TheNatureBoy9 (9:36:20 AM): thats freaking nothing

TheNatureBoy9 (9:36:43 AM): i'm doing math wrong somehow

caseyoman (9:36:43 AM): so you'd need 2 batteries to power the washing machine?

caseyoman (9:36:47 AM): i doubt it

caseyoman (9:36:53 AM): how about the dryer?

caseyoman (9:37:19 AM): and what's the cost analysis?

TheNatureBoy9 (9:37:40 AM): getting a little deep for me LOL

TheNatureBoy9 (9:47:30 AM): average dryer on this one site says 3.3kwh

TheNatureBoy9 (9:47:46 AM): which would be 3300 watts / 120 volts is 27.5 amp hours

caseyoman (9:48:24 AM): is it 120 or 240?

TheNatureBoy9 (9:48:38 AM): so if its 240 then divide down to 14 amp hours

TheNatureBoy9 (9:48:43 AM): still way more than the washer

caseyoman (9:48:55 AM): yeah, clothes lines may make a comeback

TheNatureBoy9 (9:49:00 AM): yep

caseyoman (9:49:03 AM): well, maybe not in cary

TheNatureBoy9 (9:49:17 AM): but still something a good 100 amp hour battery can handle

caseyoman (9:49:43 AM): or 100 1 amp batteries

caseyoman (9:49:51 AM): in a shed

TheNatureBoy9 (9:50:04 AM): true

caseyoman (9:50:08 AM): that'll look good on the moncure land

caseyoman (9:50:23 AM): if you convince e it's a good long term plan, i'll work on building it

TheNatureBoy9 (9:50:52 AM): lol

TheNatureBoy9 (9:51:05 AM): ill see what i can do

TheNatureBoy9 (9:51:12 AM): we can blog about it

caseyoman (9:51:26 AM): true, hell, just post this conversation.

TheNatureBoy9 (9:51:27 AM): how i ran my house on 20,000 double A batteries

caseyoman (9:51:36 AM): then have cory write up the retraction

TheNatureBoy9 (9:51:51 AM): yeah ill do that

caseyoman (9:51:51 AM): screw that, used hearing aid batteries