Reply
 
Thread Tools Display Modes
 
Old 12-24-2008, 12:32 AM   #1
Skoolie
 
Ray_WA's Avatar
 
Join Date: Nov 2008
Posts: 193
Year: 1991
Coachwork: BlueBird
Chassis: GMC
Engine: 6.2 liter diesel
Rated Cap: 24
Re: Solar Input

I cant' really comment too much on your numbers and figuring as I haven't gotten that far. They do take into account things I do know, which is that a battery is rated under "perfect" conditions and therefore maximum AH's are often more theoretical than actual. And you're right, you don't want to drain past 50%.

I see you're a fan of AGM's!! I have one and think all new additions will also be AGM.

Now... why would you want to live all alone in a huge bus?

-Ray
__________________
Pack up your bus and bug out to the hills!
Ray_WA is offline   Reply With Quote
Old 12-24-2008, 07:34 AM   #2
Bus Nut
 
Join Date: Dec 2006
Location: downriver, detroit mi
Posts: 794
Re: Solar Input

smitty;
i just went thru the latest mother earth news energy aver edition, lots of good information, most notably updates on solar panel technology, not much on storage as most current home systems are connected to the grid as the power companies are required to buy back the extra power produced at the going rate.

i think that with the current push for hybred vehicles that new battery technology is on the horizon especcialy from the asians.

has anyone looked at industrial batteries like forklift batteries ?
paul iossi is offline   Reply With Quote
Old 12-24-2008, 10:46 AM   #3
Bus Nut
 
SeanF's Avatar
 
Join Date: Nov 2004
Location: Tucson, AZ
Posts: 524
Year: 1993
Coachwork: AmTran
Chassis: IHC
Engine: Dt360
Rated Cap: 19
Re: Solar Input

Hi Smitty-

Nice work so far...I think you're on the right track. Two comments though:

1. Those 305 Ah batteries are 6 volts, so if you get two and wire them in series you get 305Ah at 12 volts. Four of them will get you 610Ah total capacity at 12 volts. Then factor in the 50% usage limit.

2. The ad for the charging system uses 5-6 peak sun hours for determining charging capacity of the included panels. I'm not sure why they use those numbers, because it varies by location and time-of-year. There are tables showing how many sun hours can be expected depending on location and type of array (tilted, tracking, etc.)
http://rredc.nrel.gov/solar/pubs/redbook/

The tables can be a handful to look at initially, but unless you are building a tracking system, just worry about the first table.

The rows show the number of sun hours for each tilting configuration. The first row is for 0* ...or flat/untilted. Read across to see how many daily sun hours you can expect on average for each month.

"Latitude-15" means the panel array is tilted at your latitude minus 15 degrees. For example if I am at 40 degrees N Latitude and tilt my panels to 25* (from flat), the numbers on that row (Latitiude-15) are what I can expect.

You can use those numbers directly in your calcs to see how many amp-hours (or watt hours) your panels will put back into your system, on average, each day.

Sorry if that was long-winded but it took me a few tries to figure out the tables and I wanted make it easier for others if possible.

HTH
Sean
__________________
Bus conversion/info here
SeanF is offline   Reply With Quote
Old 12-24-2008, 02:03 PM   #4
Skoolie
 
Join Date: Feb 2005
Location: Winnemucca, NV/Reno NV
Posts: 176
Year: 1980
Coachwork: Gillig 1980, 2003 Thomas E-350 shorty
Chassis: 636/E350
Engine: Cat 3208 NA/7.3
Rated Cap: 78
Re: Solar Input

What kind of 12v fridge will you use? You'll want one of the higher efficiency compressor models, and it will need to be vented to the outside to remove heat. Build it into a cabinet and use low draw 12v fans to circulate air out thru the bus wall. Or put a roof vent for a RV fridge in and let gravity do the vent work. Otherwise the heat is dumped into the bus, making the fridge (and your cooling fan)s work harder. You won't operate a 2 or 3 way RV fridge on 12v for long. I'd opt for a propane RV fridge. It should really free up a lot of electric reserve.

I lived at BurningMan for a month last year, with 334 watts of solar (flat mounted), 5 Walmart group 29 RV batteries and a LP RV fridge. We were able to use 1 to 3 laptops, make a couple 4 cup pots of drip coffee, use the microwave (sparingly), lights, music. There were a few eves when the voltage dropped lower than I'd like, but not real critical. 3 of the batteries were over 1 yr old, had wintered thru sub zero temps, and suffered some healthy discharges the year before, so they prob dragged the system down a bit. Also, I pre-cooled the fridge, and ran it off the solar/inverter for the few hour drivew to BM; Really dragged the batt voltage down, even with full midday sun.

The year before, we were at BM a bit less than a month; the 334 watts plus 3 24 watt panels and 3 Walmart batts could barely keep up with a 4 cu ft dorm fridge. Unvented, the outside of the fridge would get hot!! These little things have an insanely inefficient design. My putting it under a counter w/ no venting made it much worse. Love my propane fridge!! A week of clouds isn't going to hurt it, nor will parking in the shade.
__________________
If it isn't grown, it has to be mined
http://weathersticker.wunderground.c...Winnemucca.gif
elkoskoolie is offline   Reply With Quote
Old 12-24-2008, 03:06 PM   #5
Bus Nut
 
SeanF's Avatar
 
Join Date: Nov 2004
Location: Tucson, AZ
Posts: 524
Year: 1993
Coachwork: AmTran
Chassis: IHC
Engine: Dt360
Rated Cap: 19
Re: Solar Input

Cool Smitty. I figured you knew about the sunshine vs. latitude stuff, I'm just never sure how much info & opinions to spew, so I just start blabbing. No offense intended amigo.
__________________
Bus conversion/info here
SeanF is offline   Reply With Quote
Old 12-24-2008, 05:33 PM   #6
Almost There
 
Join Date: Nov 2008
Posts: 78
Year: 92
Coachwork: Bluebird
Chassis: TC2000
Engine: 5.9 Cummins
Rated Cap: 72
Re: Solar Input

Quote:
Originally Posted by Smitty

Are 6V batteries genetically higher AH than 12V? I guess I really haven't paid attention, and was paying more to AH and physical size. I may have to relocate where I intend to stow the batteries to ensure room for more reserve capacity.

Thanks
Smitty
I assume you meant "generally", not "genetically" and yes 6v batteries are generally higher AH batteries than 12v because they tend to be built to similar external dimensions but a 6v has fewer cells so each cell can be larger, therefore contain more lead and electrolyte, therefore more AH per cell and since the cells are series and AH are not added the AH of the battery can be no larger than the AH that can be built into each cell
bbbrt76 is offline   Reply With Quote
Old 12-25-2008, 01:42 PM   #7
Skoolie
 
Join Date: Feb 2005
Location: Winnemucca, NV/Reno NV
Posts: 176
Year: 1980
Coachwork: Gillig 1980, 2003 Thomas E-350 shorty
Chassis: 636/E350
Engine: Cat 3208 NA/7.3
Rated Cap: 78
Re: Solar Input

If you're going to stay with an electric fridge, one option is the freezer to fridge conversions. Basically a top open freezer, add an internal thermocouple and controller to make it cycle on-off to keep temps in a fridge zone. They can run well off a relatively small inverter. There's lots of info out on the web, (if you can sort thru all the folks that only want to make money).. If you get the right freezer, they're supposed to be VERY efficient as a fridge. I think you can get the temp probe and controller from a beer and wine making shop. I believe some freezers dissipate heat through the skin, so I'd run it first before insulating, building an enclosure etc. Biggest trouble for us Skoolies is the floor space it takes up, and area above to let the lid open. I came really close to doing this, but opted for conventional RV fridge.

http://www.builditsolar.com/Projects/Co ... fridge.pdf

and a discussion of above
http://www.wind-sun.com/ForumVB/showthread.php?t=9

You can spend the time to find more!!!
__________________
If it isn't grown, it has to be mined
http://weathersticker.wunderground.c...Winnemucca.gif
elkoskoolie is offline   Reply With Quote
Old 12-25-2008, 02:46 PM   #8
Skoolie
 
Ray_WA's Avatar
 
Join Date: Nov 2008
Posts: 193
Year: 1991
Coachwork: BlueBird
Chassis: GMC
Engine: 6.2 liter diesel
Rated Cap: 24
Re: Solar Input

Quote:
Originally Posted by elkoskoolie
If you're going to stay with an electric fridge, one option is the freezer to fridge conversions. Basically a top open freezer, add an internal thermocouple and controller to make it cycle on-off to keep temps in a fridge zone. They can run well off a relatively small inverter.
Hey, this is a neat idea. I am months off from buying a fridge for my bus but I have spent some time looking at various options and have never considered this one. I always liked the top opening chest freezers because they don't let all the cold air out when you open them! This means you can open them longer and more frequently without losing as much cold air. It's gotta be more efficient.

One more thing to look at and consider!

-Ray
__________________
Pack up your bus and bug out to the hills!
Ray_WA is offline   Reply With Quote
Old 12-25-2008, 06:33 PM   #9
Bus Nut
 
SeanF's Avatar
 
Join Date: Nov 2004
Location: Tucson, AZ
Posts: 524
Year: 1993
Coachwork: AmTran
Chassis: IHC
Engine: Dt360
Rated Cap: 19
Re: Solar Input

Quote:
Originally Posted by Smitty
Sean- No offense taken, hope you didn't think that. Appriciated your input. lol, I don't think one can offer too much info. What doesn't benefit one (and not saying it didn't me, it did) can benefit another.

Thanks
Smitty
It's all good. The internet is an excellent medium for exchanging info and ideas, but sometimes I like to check to make sure wires haven't crossed somewhere.

Cheers!
Sean
__________________
Bus conversion/info here
SeanF is offline   Reply With Quote
Old 12-25-2008, 09:54 PM   #10
Almost There
 
Join Date: Nov 2008
Posts: 78
Year: 92
Coachwork: Bluebird
Chassis: TC2000
Engine: 5.9 Cummins
Rated Cap: 72
Re: Solar Input

Quote:
Originally Posted by Smitty

That being said, I'm wondering if there is any advantage other than a few extra AH when comparing 2-6V to 1-12V? Connecting 2-6V would add alittle cost (wiring & connectors) initially, as would mounting twice as many batteries using 6V's.

Thanks
Smitty

The advantage with a pair of 6v's is generally they are more resistant to vibration and physical shock because the plates tend to be thicker than in 12v, but 12v will usually let you pack more AH into a given amount of space and usually will be lighter for a given pack rating
bbbrt76 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Solar ovens and solar water heaters/showers tomas_maly Heating, Cooling and Appliances 6 05-22-2013 12:43 PM
looking for a NEW(er) bus... input appreciated :) chev49 Classifieds | Buy, Sell, Swap 4 05-05-2012 03:02 AM
any input on this bus? goinbussin Short-Bus Conversion Projects 9 07-06-2011 01:44 PM
Looking for input............ odyssess Everything Else | General Skoolie Discussions 1 04-25-2008 08:48 PM
Input on vintage bus please itsart Conversion General Discussions 1 10-06-2007 09:18 PM

» Virginia Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 12:09 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.