Reply
 
Thread Tools Display Modes
 
Old 12-08-2003, 03:04 PM   #1
Bus Crazy
 
Steve's Avatar
 
Join Date: Jul 2002
Location: Central Iowa
Posts: 1,838
Send a message via AIM to Steve
If you want a cheap inverter/charger/transfer switch buy a used UPS (uninteruptable power supply) off of eBay that has a bad battery. These units are made to power computer equipment when the power goes out. They have a 12 V battery inside of them and most people get rid of them when the battery quits.



Basically they are the same thing as what you would buy for an RV. You can hook them directly up to any 12V battery and they have a good battery management system in them so you don't have to worry about overcharging. When you turn them on they will start producing 120V and if you plug it into a 120V source it will automatically switch over to that source and start charging your batteries. I should add that these units have the best transfer switches you can find anywhere. You will never see a flicker when it switches.



At the local surplus sale they are selling 1000W UPS systems with dead batteries for around $20.
__________________
View my 1972 Ward: Topic from the Build : The Picture Gallery
View my 1986 Blue Bird: Topic from the Build : The Picture Gallery
View my 1960 GMC: Topic from the Build : The Picture Gallery
Steve is offline   Reply With Quote
Old 12-08-2003, 03:06 PM   #2
Bus Crazy
 
Steve's Avatar
 
Join Date: Jul 2002
Location: Central Iowa
Posts: 1,838
Send a message via AIM to Steve
Since they are so cheap it's pretty cost effective to use a different UPS for each circuit in your bus eliminating the need for a circuit breaker panel. You can run 12V dc wire to any location in your bus you want one of these things, and then just use one of them near your battery as the transfer switch/charger.



Also, if you get one I would recommend getting an APC brand UPS.
__________________
View my 1972 Ward: Topic from the Build : The Picture Gallery
View my 1986 Blue Bird: Topic from the Build : The Picture Gallery
View my 1960 GMC: Topic from the Build : The Picture Gallery
Steve is offline   Reply With Quote
Old 12-17-2003, 02:46 PM   #3
Bus Crazy
 
Steve's Avatar
 
Join Date: Jul 2002
Location: Central Iowa
Posts: 1,838
Send a message via AIM to Steve
I bought a UPS from the local university surplus sale today. I got a 1000W for $10. I'll post pictures and describe how well it works soon.



__________________
View my 1972 Ward: Topic from the Build : The Picture Gallery
View my 1986 Blue Bird: Topic from the Build : The Picture Gallery
View my 1960 GMC: Topic from the Build : The Picture Gallery
Steve is offline   Reply With Quote
Old 12-17-2003, 11:16 PM   #4
Bus Crazy
 
Steve's Avatar
 
Join Date: Jul 2002
Location: Central Iowa
Posts: 1,838
Send a message via AIM to Steve
When I opened up the case I found two batteries connected in series.







The batteries are 12V 17.2Ah each. They were connected to the ups by two 10 AWG wires to each terminal. So I will be selected 4 AWG wire to connect the UPS to my battery bank.







It would seem that the UPS systems above 600 Watts run on 24 V which would be something you will want to consider if you try doing this. Also note that this unit has a fan to keep it from overheating.
__________________
View my 1972 Ward: Topic from the Build : The Picture Gallery
View my 1986 Blue Bird: Topic from the Build : The Picture Gallery
View my 1960 GMC: Topic from the Build : The Picture Gallery
Steve is offline   Reply With Quote
Old 01-19-2005, 02:09 AM   #5
Skoolie
 
Join Date: Jan 2005
Posts: 238
So how is it working out?.....I know of a used ups here I can get if this worked out for you.
Demonknight is offline   Reply With Quote
Old 01-19-2005, 04:47 PM   #6
Bus Crazy
 
Steve's Avatar
 
Join Date: Jul 2002
Location: Central Iowa
Posts: 1,838
Send a message via AIM to Steve
The annoying beep problem is easy, you can just remove the buzzer then with your multimeter measure the resistance across the buzzer itself and replace it with the same size resistor. ( Or just leaving nothing there should work in most situtations. )

To take care of the charging situation, why would you want to disable, it would work like a perfect transfer switch/charger. If you are plugged into shore power or generator why not let it charge the batteries.
__________________
View my 1972 Ward: Topic from the Build : The Picture Gallery
View my 1986 Blue Bird: Topic from the Build : The Picture Gallery
View my 1960 GMC: Topic from the Build : The Picture Gallery
Steve is offline   Reply With Quote
Old 01-20-2005, 11:23 AM   #7
Bus Crazy
 
Steve's Avatar
 
Join Date: Jul 2002
Location: Central Iowa
Posts: 1,838
Send a message via AIM to Steve
If I was going to use multiple UPS I would have given each their own battery, That way you can match each bank to the appliances that it will be running, plus you wont have to be running high current wires around everywhere.

I understand the efficient thing but if your plugged into shore power why care.
__________________
View my 1972 Ward: Topic from the Build : The Picture Gallery
View my 1986 Blue Bird: Topic from the Build : The Picture Gallery
View my 1960 GMC: Topic from the Build : The Picture Gallery
Steve is offline   Reply With Quote
Old 01-20-2005, 06:32 PM   #8
Skoolie
 
Join Date: Jan 2005
Posts: 238
Hmmm..so Steve is going to use his to control a large bank of batts, while Soul is looking at a group of apc's each hooked to the same batts????..you two are confuseing me *S* I was looking at breaking the elec. into groups based on when/where they would be used and what they need (power wise)...Right now I'm only trying to get my laptop and its base station into the bus as its going to be my atlas/sound system for my move home.
Demonknight is offline   Reply With Quote
Old 01-20-2005, 09:32 PM   #9
Skoolie
 
Join Date: Jan 2005
Posts: 238
hmmm, oddly I started that last year before I had it (working on it)..but thats for a page on the bus and not here *S* guess I'll go ahead and snag that ups and hope its not toast on the circets (sp?) ... all I need right now is enough to power my laptop..after that I have a camper van thats giveing up it goodies to the bus waiting in CO.
Demonknight is offline   Reply With Quote
Old 01-20-2005, 10:32 PM   #10
Bus Geek
 
lapeer20m's Avatar
 
Join Date: Nov 2003
Location: near flint michigan
Posts: 2,653
I feel I am a creative electrical wizard when it comes to making things work both 12 and 110 volt, but I decided to use the KISS theory in my bus. My entire bus runs off of one 15 amp circuit. That circuit enters the bus through a GFI, then branches out to a series of plain 110 volt light switches that control the individual circuits ie: fridge, outlets, aux, and lights. I have a male plug that feeds power to the bus, and three electrical outlets that i can tap into: Shore power, Inverter, Generator. I have to manually move the plug from one outlet to another when switching power sources, but this ensures that i won't fry my inverter, or generator by accidentally plugging one into the other.

My electrical system is cheap, simple, and reliable.
__________________
Quis custodiet ipsos custodes (who will watch the watchmen?)
lapeer20m 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
1 inverter and 3 outlets ThePimentals Electrical, Charging and Solar 17 09-25-2014 08:26 AM
Inverter FAQ's lornaschinske Conversion Tutorials and How-to's 4 08-13-2012 09:15 PM
new inverter/generator gbstewart Conversion General Discussions 3 12-17-2010 02:42 PM
What Inverter To Get? lapeer20m Conversion General Discussions 1 05-14-2010 01:31 PM
Why use an inverter? lapeer20m Conversion General Discussions 5 09-07-2008 06:01 PM

» Virginia Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 11:32 AM.


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