Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 01-04-2010, 12:12   #1
Senior Cruiser
 
schoonerdog's Avatar

Cruisers Forum Supporter

Join Date: May 2004
Location: annapolis
Boat: st francis 44 mk II catamaran
Posts: 1,174
Images: 4
Up-Converting Voltage from .56 Volts to 12.6 Volts

I have a low wattage application which runs on 12 volts. I can buy individual cells pretty cheaply which are 4 watts putting out .56 volts. Does anyone know of a source where I can buy a small, cheap converter to convert this voltage from .56 volts to 12.6 volts?
__________________

schoonerdog is offline   Reply With Quote
Old 01-04-2010, 12:13   #2
Senior Cruiser
 
schoonerdog's Avatar

Cruisers Forum Supporter

Join Date: May 2004
Location: annapolis
Boat: st francis 44 mk II catamaran
Posts: 1,174
Images: 4
If there's nothing out there as a small electronic part, any kits, or DIY solutions?
__________________

schoonerdog is offline   Reply With Quote
Old 01-04-2010, 13:08   #3
Registered User

Join Date: Jun 2009
Location: STX and Portland, until refit finished
Boat: 1999 Steel (Tom Collin's design)
Posts: 371
Stick 22 of them in series, and you should be good to go.

It should actuly deliver 12.3 volts, but that should be close enough, cause as soon as you put a little load, they'll probably drop down closer to 12 volts.
__________________
ViribusUnitis is offline   Reply With Quote
Old 01-04-2010, 13:16   #4
Senior Cruiser
 
schoonerdog's Avatar

Cruisers Forum Supporter

Join Date: May 2004
Location: annapolis
Boat: st francis 44 mk II catamaran
Posts: 1,174
Images: 4
Yes, but the result would be 22 x 4 watts, or 88 watt panel. Way to large for my application, hence the need to try to simply upconvert the voltage of the single 4 watt cell.
schoonerdog is offline   Reply With Quote
Old 01-04-2010, 15:29   #5
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2005
Boat: Outbound 44
Posts: 4,580
You can find DC-to-DC converters that will do 3.3 v to 12v in places online like
DC/DC-Converter Power Flex Search - RECOM

Paul L
__________________
Paul L is online now   Reply With Quote
Old 01-04-2010, 16:04   #6
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
Quote:
Originally Posted by schoonerdog View Post
Yes, but the result would be 22 x 4 watts, or 88 watt panel. Way to large for my application, hence the need to try to simply upconvert the voltage of the single 4 watt cell.
you mean solar cells? get a miniature 12V panel instead, available from 1W up, like here: Kyocera 1.2W 12V Mini Solar Panel - 1 to 50 Watt Solar Panels @ AltE

cheers,
Nick.
__________________
s/v Jedi is offline   Reply With Quote
Old 02-04-2010, 04:24   #7
Marine Service Provider
 
LiFeTech Energy's Avatar

Join Date: Mar 2010
Posts: 84
As Paul L has suggested you can connect 6 cells in series and then use a 3.3V - 12V DC/DC converter (which are quite common).
__________________
LiFeTech Energy -When quality and performance is what matters most.
LiFeTech Energy is offline   Reply With Quote
Old 02-04-2010, 06:33   #8
Senior Cruiser
 
schoonerdog's Avatar

Cruisers Forum Supporter

Join Date: May 2004
Location: annapolis
Boat: st francis 44 mk II catamaran
Posts: 1,174
Images: 4
I've been looking at some smaller wattage 12v panels. The issue is mainly cost. A single 4 watt solar cell you can buy for around $5. A 4 watt 12v panel of similar power would cost around $75. I do see things out there that look like they are 12v chargers with two siemens monocrystalline cells put together (probably in series) and charge at 12v like this Amazon.com: 4 Watt 250 MA 12V Mono-crystalline zipper bag Solar Battery Charger Kit with Siemens Solar Cells: Electronics. If each cell is .5 volts than they up converting the 1v output to 12.6 volts somehow. So it can be done I guess. Maybe I should buy one, tear it apart and see what they are using....
schoonerdog is offline   Reply With Quote
Old 02-04-2010, 06:57   #9
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2006
Location: Chesapeake Region and Maine
Boat: 42' Bob Perry sloop
Posts: 4,038
Images: 4
You can buy a new 4.5 watt solar panel for $44:
COLEMAN NEW 300MA 4.5 WATT SOLAR PANEL CL-300 - eBay (item 170456575518 end time Apr-07-10 18:39:46 PDT)

How much is your time worth to screw around with building one? :-)

B.
__________________
btrayfors is offline   Reply With Quote
Old 02-04-2010, 10:14   #10
Senior Cruiser
 
senormechanico's Avatar

Cruisers Forum Supporter

Join Date: Aug 2003
Boat: Dragonfly 1000 trimaran
Posts: 5,827
How about 2 of these?
6V 100mA 0.6W small solar panel with a diode inside - eBay (item 390175990094 end time Apr-04-10 10:24:52 PDT)
__________________
Memento,homo, quia pulvis es, et in pulverem reverteris.
senormechanico is online now   Reply With Quote
Old 02-04-2010, 13:42   #11
Senior Cruiser
 
schoonerdog's Avatar

Cruisers Forum Supporter

Join Date: May 2004
Location: annapolis
Boat: st francis 44 mk II catamaran
Posts: 1,174
Images: 4
Thanks for that link. I see they also sell this:
17.5V 290MA 5W solar panels solar power panels 5watt - eBay (item 220410887009 end time Apr-03-10 00:53:20 PDT)

That goes for $5 watt or $25 which is really in the ball park, especially since they seem to be well made.

Now a question, if the device I'm charging just has a 2.1 amp hour battery, would a 5 watt panel need to be regulated?

schoonerdog is offline   Reply With Quote
Old 02-04-2010, 15:26   #12
Registered User

Join Date: Jun 2009
Location: British Columbia & Cape Coral
Boat: Beneteau 311
Posts: 148
You are best not over-voltaging the battery, dependant on the battery type, it will have a voltage which it's best not to exceed (small gel cells are usually 2.35 Volt/cell, for example), and that should be what your power supply is set to.

Bill
__________________
ctsbillc is offline   Reply With Quote
Old 04-04-2010, 12:37   #13
Registered User
 
boat_alexandra's Avatar

Join Date: Aug 2009
Location: Masachusetts
Boat: bristol 27
Posts: 2,803
putting cells in series reduces shade tolerance of the panel, however it is probably really inefficient to convert .5 volts up to 12. If you had at least 3 volts to work with the efficiency would probably be more like 80% with a DC/DC boost converter. The other advantage is you could set the DC/DC converter to 14.4v so it would never overcharge the battery.
__________________
boat_alexandra is offline   Reply With Quote
Old 04-04-2010, 22:34   #14
Senior Cruiser
 
senormechanico's Avatar

Cruisers Forum Supporter

Join Date: Aug 2003
Boat: Dragonfly 1000 trimaran
Posts: 5,827
I really doubt you will find any electronics which will work on 0.56 volts in the first place.
The forward biased conduction point of a silicon junction is around 0.7 volts.
__________________
Memento,homo, quia pulvis es, et in pulverem reverteris.
senormechanico is online now   Reply With Quote
Old 04-04-2010, 23:01   #15
Registered User

Join Date: Jun 2009
Location: British Columbia & Cape Coral
Boat: Beneteau 311
Posts: 148
Ah, don't think bopolar. Don't necessarily think Silicon either (Germanium is 0.2V)

Here's a ultra low voltage charge pump Overview - Ultra-Low Voltage Operation Charge Pump IC for Step-up DC-DC Converter Startup S-882Z series

Still true that it's not the way to go though, put the cells in series, and make sure none of them are shaded.

Bill
__________________

__________________
ctsbillc is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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
Need Manual Troubleshooting Norcold SCQT-6406 works AC volt not DC volts ? chuck711 Plumbing Systems and Fixtures 6 03-11-2013 11:30
12 or 24 Volts? S&S Electrical: Batteries, Generators & Solar 22 22-12-2009 22:41
12.5 Volts Fully Charged? Meck Electrical: Batteries, Generators & Solar 7 18-09-2009 09:12
Getting Up to 14.8 Volts with Solar svpresent Electrical: Batteries, Generators & Solar 6 16-09-2009 00:23
1Amp Trickle Charger Putting Out 15.34 Volts Northeaster Electrical: Batteries, Generators & Solar 4 23-03-2009 15:57



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 12:15.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.