| Author |
Message |
Buddy Tennison (Buddyten)
Registered Member
Username: Buddyten
Post Number: 36
Registered: 7-2005
Posted From: 207.68.234.24
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 02, 2007 - 12:29 am: | |
We are thinking of making a change in some interior lighting. We now have light valances that run down each side of the coach. In those valances, we installed some 12V lights which actually are "up lighting". We went to the salvage yard, and got some dome lights out of wrecks. We are thinking about changing these out to flourescent low profile lights.
A couple of questions and requests for your thoughts:
1. The light fixtures I found at Lowes that would work well dimensionally are 12" single bulb 40W fixtures (110V). They are about $10 bucks each. The similar 12V fixtures I have found are close to $50 bucks each. Could I use a Radio Shack type inverter run off my genset batteries to power the 110V lights. Best I can tell, a 1000W inverter of this type would be somewhere around $100 bucks. We are thinking about having a total of 10 fixtures, which doing it this way would be $100 for light fixtures (10 @ $10 ea) and another $100 for the inverter. To use the 12V fixtures would be around $500 (10 @ $50 ea). Any thoughts or suggestions.
2. We currently have one 8D battery to run our generator. If I hooked another one (primarily to run these lights) together, and I hooked my battery charger to one, would both of them be charged. Any thoughts or suggestions on a better arrangement.
Thanks guys for all your help. WE are still learning. |
Luvrbus (Luvrbus)
Registered Member
Username: Luvrbus
Post Number: 80
Registered: 8-2006
Posted From: 74.32.88.185
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 02, 2007 - 9:42 am: | |
Buddy, you should you look at the 12v screw in type flourecent blub they cost about 8 bucks and you can buy screw in bases at Lowes or Hd if you have the room this is the way to go (dyer's rv supplies)they have a web site.you can install thse in any direction the problem i have always had with 12V rv tube lights when the power gets low it ruins the light and i don't like paying 50 bucks for something that won't last
(Message edited by luvrbus on August 02, 2007)
(Message edited by luvrbus on August 02, 2007) |
James Stacy (Jimstacy)
Registered Member
Username: Jimstacy
Post Number: 83
Registered: 1-2001
Posted From: 75.40.225.249
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 02, 2007 - 11:52 am: | |
Be careful with 120v flourescents if you intend to run them with an inverter other than "pure sine wave". I had some HD units turn into crispy critters. After all the dust had settled and the shouting was over, the best 12v lights are "Thin Lights". They work and last.
BTW if you are running your 12v down far enough to give Thin Lights a problem you are abusing your battery as well. Better to increase capacity rather than drive batteries to below 50%. IMHO
Jim Stacy |
George M. Todd (George_mc6)
Registered Member
Username: George_mc6
Post Number: 239
Registered: 8-2006
Posted From: 207.231.81.129
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 02, 2007 - 3:18 pm: | |
Buddy,
Here's the reality math on your question. A fluorescent light uses approximately 1/4 the electrical current of its equivalent incandescent light brother. So, a 40 watt fluorescent will use about 10 watts of power. Then, 10 fixtures will use about 100 watts, at 120 Volts, which is about 0.8 of an amp. A cheap modified sine wave inverter, (which is what you describe) is only about 80% efficient, meaning you will draw about 10 amps out of your generator starting battery to run your lights. Adding the cost of another 8D would make the 12v lights more cost effective, not to mention you must take Jim's post immediately above, at face value! What are you doing for house batteries?
George |
Chris Peters (Chris_85_rts)
Registered Member
Username: Chris_85_rts
Post Number: 41
Registered: 11-2006
Posted From: 66.194.150.45
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 02, 2007 - 5:43 pm: | |
I am a little confused by the statement "one 8D battery to run our generator". Why use an 8D battery for a generator? Did you mean to say for an inverter?
Now, I can see maybe using an 8D battery for a house battery, but most would opt for two golfcart batteries, as they are easier to handle. Parallel as many batteries as you want, but be sure to not use combinations of different battery types or different capacities or different ages. Best to set it all up at once. However, I would never use my genset battery as my house battery. If all my batteries are dead, I at least want to be able to start my genset.
You need to know your expected current draw (either 12V with 12V fixtures or 12V with 120V fixtures on an inverter). Once you know your expected current draw, divide that into your batteries amphour rating and you can see how long your batteries could be expected to last.
But here is the kicker. For every amphour you take out of a battery you have to put it back. Not only that, but it seldom can go back faster than you took it out. I guess that depends on your draw. If you draw say 5A, and charge with 30A you can charge faster than it came out, but if you draw 200A, you can't charge at a constant 200A, at least I don't think you can and have happy batteries. Anyway, I digress. The point was that you have to look at your charger, and see if it will charge you back up in a reasonable time. Just divide battery capacity (amphours) by charging rate.
Suppose you have a 800 amphour battery setup. You can draw 10 A for 80 hours. Suppose you can charge at 30A, well that is going to take 26 hours. Whoa. So now we are talking about a staged charger.
Next to the engine, power is the most expensive part of the coach. 5K for a genset, 3k for an inverter, 1k or more for batteries, 3 stage charger, it all adds up. But if you want to run on batteries for an extended period of time, you gotta bite the bullet and do it right.
For me personally, unless you can't run the genset or will not be near a pole, I'd use the 120V fixtures power off the genset. And then maybe a small inverter for 5 mintues here and there when the genset is not running. |
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