| |
Subject |
Author |
Date Posted |
Forum
|
 |
RE: Solar Controller Safety?-(was " Sliding Out the Fridge" )
Last comment. I was just trying to make things easier for people to understand. Automotive systems are called 12v systems even though batteries have higher voltages. Solar panels are called 12 volt (or 24 volt) even though they put out 17 volt (or 34 volt). I figured that it would be easier to understand multiples of 12 volt panels instead of throwing a 24 volt panel into the mix. Why do you think that MTTP controllers will handle 36 volts? Because you can use 24 volt (34 volt output) panels with them allowing the use of smaller sized wire.
You happen to know why panels are made to output 17v instead of 14.5v? To make sure they can provide enough voltage with the wire voltage loss. A volt or two of loss and they can still provide enough voltage to charge a battery. The controller is limited to 14.4 volts (as an example) so any voltage loss means less voltage to the battery.
There are dozens (maybe 100's or 1000's) of web sites that explain wire resistance and the effects it has, maybe it should by read by some when designing a system. Bob is not the holy grail, but he understands ohms law and wire resistance. But then it appears you know all. LOL
I'm done, you can comment again just to get the last word if you wish :)
BFL13, please take the time to research solar panel wiring so you will get the most out of your system. Since you are going this far into it, spend a few extra hours and a few extra dollars to get it right and get the most out of your expensive system. If you spend $1000 on panels, a 10% loss because of wiring is like throwing away $100.
|
HobbyTalk
|
03/18/10 07:03pm |
Tech Issues
|
|
RE: Census??
I was at the Michigan DMV today and they had forms out on the table that you could take. Not sure what other places they are available or what other states are doing.
|
HobbyTalk
|
03/18/10 06:41pm |
Full-time RVing
|
|
RE: Hooking Inverter to Trailer AC
SMK, thanks, that's what I thought. Was just double checking.
Jack, Yep, have a breaker to turn it off.
|
HobbyTalk
|
03/18/10 05:34pm |
Tech Issues
|
|
RE: Solar Controller Safety?-(was " Sliding Out the Fridge" )
Nevermind. I see you know the best way to install a solar system :)
http://handybobsolar.wordpress.com/2009/07/22/solar-power-that-works/
|
HobbyTalk
|
03/18/10 04:17pm |
Tech Issues
|
|
Hooking Inverter to Trailer AC
While looking at inverters I notice that the one's I looked at have two 15 amp 110v plugs. I want to be able to hook my trailer's 30 amp AC cable to it. How do you convert the two 15 amp outlets to a 30 amp outlet or do you just use a single 30/15 adapter? Figure I'll never draw more then 15 amps so maybe just using an adapter is good enough? Don't think drawing say 10 amps max through a single plug won't hurt anything?
|
HobbyTalk
|
03/18/10 02:58pm |
Tech Issues
|
|
RE: Solar Controller Safety?-(was " Sliding Out the Fridge" )
The main reason to use a MPPT controller is so you can wire your panels in series instead of parallel. This will increase the voltage from the panels and decrease the current (amps). High voltage/Low current means lower voltage drop in a wire... the same reason long distance high tension lines run at 1000's of volts. The MPPT controller then takes this higher voltage and converts it down to the proper charging voltage and increases the current.
Ohms law
single 120 watt panel = 12v @ 10 amps
3 40 watt panels in series = 36v @ 3.3 amps
The 3 panel system would have 1/3 the voltage drop in the same size wire.
|
HobbyTalk
|
03/18/10 02:01pm |
Tech Issues
|
|
RE: Solar Controller Safety?-(was " Sliding Out the Fridge" )
That is not true. Does not matter the controller type. Current boost makes no difference as we are talking voltage loss and the voltage would have to be boosted to compensate for voltage loss. In fact boosted current will make the voltage loss even worse.... simple ohms law. A solar panel will put more then the required voltage. Your controller/charger will reduce this voltage to the proper level to charge your batteries. Let me try to draw a picture here so you can understand.
Diagram with long wires from controller to battery
solar panel outputs = 17v
voltage in to controller due to voltage drop 15' of #10 wire = 16v
voltage out of controller = 13.8v
voltage to battery due to voltage drop 15' of #10 wire = 13v
Diagram with short wires to battery
solar panel outputs = 17v
voltage in to controller due to voltage drop 30'of #10 wire = 15v
voltage out of controller = 13.8v
voltage to battery due to voltage drop of 1' of #10 wire - 13.7v
So which would you rather have, 13v or 13.7v to your battery. In the end, they whole system from panels to battery should be rewired with at the very least #4 wire. In the end, you are losing 10% of your panels efficiency minimum using too small a wire, why waste that money spent on high $$$$ panels?
Want to check this? run your batteries down to 60% then start charging from your panels. Check the voltage at the controller, then check it at the batteries. Tell us what the voltages are.
|
HobbyTalk
|
03/18/10 01:45pm |
Tech Issues
|
|
RE: Do You Have Carbonite
I use it. Works well with no slow downs. I like using it, files are encrypted before they are sent and can only be decrypted by your computer. House burns down or is destroyed while gone? No worry, files are off site to recover.
When I switched from a PC to Mac it was easy to transfer the subscription and download my backed up files.
|
HobbyTalk
|
03/18/10 01:22pm |
Technology Corner
|
|
RE: Corpus Christi and Galveston
I stayed at Mustang Island State Park 2 weeks last month and really liked it. Main reason was being so close to the gulf. Sites have W/E, are close on one side (10' from next RV) and have a covered picnic table on the other (30' from next RV). No shade, easy parking, bath/showers close by. WiFi at main building but was able to get it at site using external WiFi adapter/antenna. Verizon cell/data is good.
Also stayed a week at Gulf Waters. IMHO way over priced for what you get.
|
HobbyTalk
|
03/17/10 08:24pm |
Snowbirds
|
|
RE: Solar Controller Safety?-(was " Sliding Out the Fridge" )
Yes it is. Read up on wire resistance and voltage drop. Eaxmple for a 12v system @ 20 amp charge rate using #4 wire
1 foot of wire from controller to battery = 0.1% voltage drop or at 13.8v controller output 13.78v gets to battery
15 foot of wire from controller to battery = 1.5% voltage drop or at 13.8v controller output 13.6v gets to battery
Which would you rather have charging your battery?
But then this prewired system most likely has #10 wire so lets run the numbers again using a properly wired system vs what is there
1 foot of #4 wire from controller to battery = 0.1% voltage drop or at 13.8v controller output 13.78v gets to battery
15 foot of #10 wire from controller to battery = 6.2% voltage drop or at 13.8v controller output 12.93v gets to battery
I don't think the difference is measurable.
Sal
You really want to put the controller as close to the batteries as possible.
|
HobbyTalk
|
03/17/10 07:57pm |
Tech Issues
|
|
RE: US--31 FROM INDY TO HOLLAND, MI
Also, don't speed through Lakeville or LaPaz. Often see radar being used in those areas.
|
HobbyTalk
|
03/17/10 12:13pm |
Roads and Routes
|
|
RE: Solar Controller Safety?-(was " Sliding Out the Fridge" )
You really want to put the controller as close to the batteries as possible.
|
HobbyTalk
|
03/17/10 12:08pm |
Tech Issues
|
|
RE: New Digital TV Antenna
With digital signals, for the most part, you will either have a great picture or no picture. The antenna makes no difference on the actual quality of the picture other then being able to get a signal or not. A directional antenna (batwing) will always be able to pull in a weaker signal then an omnidirectional antenna of the same size.
|
HobbyTalk
|
03/16/10 11:48pm |
Technology Corner
|
|
RE: New Digital TV Antenna
An omnidirectional will not be as good as the batwing.
|
HobbyTalk
|
03/16/10 10:13pm |
Technology Corner
|
|
RE: Testing solar panels for blocking diode?
If it's a digital multimeter you have to use the diode setting. A DMM does not put out enough voltage on the Ohms setting to bias the diode.
|
HobbyTalk
|
03/15/10 09:26pm |
Tech Issues
|
|
RE: Cleaning Black Water Tank
Thanks for the ideas, I have already done the ice trick. Will have to get the clear adapter so I know what's coming out. I bought the unit used and have no idea how it was taken care before. Since I can't see down into the tank I have no idea if there is any crud that is caked up anyplace. Just want to avoid problems down the road is all.
|
HobbyTalk
|
03/15/10 09:14pm |
Tech Issues
|
|
RE: Dealer prep & walk thru
I would say it depends on the price and if that is built-in. When I bought my used unit I was trying to get that last $100 off the price. After the dealer not coming down any further I was told that if I really had to have that last $100 off that I could forgo the walk through on the unit. I decided to take the walk through and the person doing it spend over 3 hours with me.... I think that was money well spent.
What I found out was that even though this location has both a sales floor and a service department that they are treated as two different businesses. The sales division actually is billed and has to pay the service division for the walk through. I know, it's the same company but the performance of each division is evaluated separately.
That's not to say that not only is $1100 way overboard but including it as an add-on over and above an advertised price is a bit slimy IMHO.
|
HobbyTalk
|
03/15/10 07:35pm |
Fifth-Wheels
|
|
Cleaning Black Water Tank
The connection for my toilet is not straight down to the black water tank. It has a pipe the has an angle to it so I can not see down into the tank. Any suggestions for cleaning the tank?
I could install an flush system to the tank but I have an enclosed underbelly which would make it a big pain to do so. TIA!
|
HobbyTalk
|
03/15/10 07:17pm |
Tech Issues
|
|
RE: Heading to RGV tomorrow
I haven't posted to this thread for a while but figured I'd post an update. I'm on my way home and 2 days from being there. I have one more stop to visit my sister that is on my way back.
This is my first year heading south for the winter and I traveled a lot so I could visit different areas to get an ideas for where to stay longer term next year. Along the way I stayed RGV, visited Big Bend NP, Carlsbad Caverns, White Sands, Padre Island/Mustang Island and New Orleans. Extended stays (week or more) were in RGV, Big Bend and Mustang Island.
In my 8K total miles I traveled in 10 weeks I figured I spent about $4K or $55 per day. There were no major problems, break downs or accidents during my travels. Before this I have never towed anything as big as my 5er and this trip did teach me not to fear making turns and to back it in fairly well. I got enough practice that I can setup or tear down in less then 30 minutes and I never dropped the 5er off the hitch even once ;) Truck averaged right at 9 MPG towing and I got about 15 mpg empty for a overall average of 10mpg.
It was a lot of driving and the next time I will not do that again. It was fun and I did get to see a lot of things, but I am ready to get home to rest :) Next time I will just head to RGV and sit for 2 months. Overall, a good experience and I'm glad I did it.
|
HobbyTalk
|
03/13/10 06:08pm |
Snowbirds
|
|
RE: Mobil 1 vs. the Walmart "knock off"
Oil can be the same quality. It is the additives that they add that makes the Difference. Generally only the big companies have the financial to also run an additive division
Like in any manufacturing venture - if a company is running their own brand it will be the specification they specify - not the suppliers formula. Would you supply the same product to a competitor for 1/3 the price in this case. I don't think so.re: on company size - You do know that WalMart had $406B income in 2009 and ExxonMobile had $311B? But it all come down to is that WalMart makes nothing, all WalMart branded items are made by someone else. The same as almost all private label big box store brands. Yes, any much of it is the same exact item as brand name products with a different label.
I'm not saying that the WalMart brand is the same as Mobile 1 as it isn't. But more likely then not it is the exact same thing as some brand name oil.
Just a side note. I watched a story on TV about Joe Gibbs Racing. They have their own lubrication research team and spent $1.5M on oil research the year that TV program was made. So really any size company can have an oil performance research team.
|
HobbyTalk
|
03/13/10 05:45pm |
Tech Issues
|
