Class B Electrical Systems 101

[Rok]

Maybe we should have a "B RV Electric" topic. I could use some brushing up on my electrical knowledge, particularly when it comes to RV electrical systems. I'm probably qualified to bring some people who haven't worked with electricity half way to where they should be, but I sure don't know all the ins and outs of electricity. But here is what I know:

1) The subject isn't trivial, but some questions ARE trivial.

2) There are two main systems in most RV's 110V AC (Alternating Current) and 12V DC (Direct Current).

3) You can change the power from one of the systems into the other buy using either a "converter" (turns AC into DC) or an "inverter" (turns DC into AC).

4) There is a TON of power stored in a gallon of any of the petrolium products: gasoline, propane, or diesel. That power can be converted into AC or DC using a generator. A generator is usually specific to one petrolium product, in other words, you usually can't use a diesel generator and power it with gasoline, or propane. I have seen a few strange engines that run off of both gasoline and propane gas, and theoritically they could be used to generate electricity, but I've never heard of it before.

5) It gets really confusing when you start converting Amp-Hours into Kilowatt Hours into horsepower into volts. Each mean a different thing and sometimes stuff is left out when someone talks about one of these things. (For instance when someone says a battery has so many Amp-Hours, they often leave out how many volts the battery has because a 6 Volt battery with 500 amp hours is the same size as a 12 Volt battery with 250 amp hous.

O.K., so with #5 I'm starting to get into an area that I'm not entirely sure of.

This is a subject I'm interested in, so I think I'll start another thread and duplicate this post to start it out.

If it catches wind it'll be great. If others aren't interested, I guess we will find that out as well.

..............Rocky

[Rok]

O.K. let me start it off-- maybe someone else can answer this question:

When we bought our GW Legend SE, we were told the larger version, the EX had 4 6 Volt Batteries totaling 500 amp hours, and ours has 2 12 Volt batteries totaling 400 amp hours.

I think that statement is misleading from what I know of electricity, but I'm not sure. Aren't 6 Volt amp-hours half as good as 12 Volt amp-hours? If so that statement should read that our rig has two 12 Volt batteries totaling THE EQUIVALENT of 400 6 Volt Amp-Hours.

I may be all wet here, so someone please let me know if I'm wrong or corroborate if I'm right.

Thanks.

.............Rocky

[Davydd]

Rocky, I don't know how you can have 400 amp hours on two 12V batteries. In my Legend they put in two Deka DC31DP Marine Master deep cycle batteries. According to the spec sheet they are rated at 105 amp hours which means together, 210 amp hours.

Here is the spec sheet for Deka batteries.

http://cdn.shopify.com/s/files/1/0033/6 ... 1254611993

[Rok]

That is what I was saying Davydd,

I think that GW was fudging when they were rating everything in 6 Volt terms. The EX has Four 6 Volt batteries each rated at, I suspect, 125 AH, which is 500 AH total (@6 Volts), or the equivalent of 250 AH at 12 Volts. Our SE on the other hand probably has two 12 Volt batteries rated at about 100 AH each (like yours) for 200 AH total @12 V, so the equivalent is 400 AH @ 6 V.

When they were selling it to me they told me it had 400 AH of batteries and when I rated that against other brands it sounded like a LOT more.

..........Rocky

[booster]

Originally Posted by Rok

That is what I was saying Davydd,

I think that GW was fudging when they were rating everything in 6 Volt terms. The EX has Four 6 Volt batteries each rated at, I suspect, 125 AH, which is 500 AH total (@6 Volts), or the equivalent of 250 AH at 12 Volts. Our SE on the other hand probably has two 12 Volt batteries rated at about 100 AH each (like yours) for 200 AH total @12 V, so the equivalent is 400 AH @ 6 V.

When they were selling it to me they told me it had 400 AH of batteries and when I rated that against other brands it sounded like a LOT more.

..........Rocky

125Ah 6v battery would be pretty small.

The 500AH of battery with the 6 volt batteries could be equivalent 12v rating. Trojan, for one, makes golf cart 6 volt batteries that have 260AH each at 6v, so that would give 520AH at 12v for 4 of them. It would also be nearly 300# of batteries and they would be wet cells.

I think a group 31 wet cell might get to 130AH of 12v for a total of 260AH, but I don't see how they could get 400.

Time for you to take a look at your batteries and see what they are, so you have an idea of how long they will last without power.

[Rok]

Gad, I really didn't want to check out my batteries. In order to do that, I would have to unscrew some panels in the floor. They seem to work fine--except that when we tried to use the inverter for the Keurig Coffeemaker and the microwave, it drained them pretty quickly. We now use the generator whenever we use the microwave and are dry camping.

Maybe I'll get the gumption up sometime and take the panels off and look at our batteries. If the access holes are any indication, the EX model has four SMALL 6 Volt batteries. Our access holes are nearly double the size.

.........Rocky

[markopolo]

Typical RV 6 volt batteries are rated approximately 200 ah.
You join two of them in series to make 12 volts but the the ah rating for the two batteries combined remains at 200ah.
Each battery will weigh 50 to 60 lbs.

Typical RV 12 volt batteries are rated approximately 100 ah.
You join two of them in parallel to stay at 12 volts but the the ah rating gets added together to total 200ah.
Each battery will weigh 50 to 60 lbs.

It is possible to get 12v batteries rated approximately 230ah but they are really big! The size is known as 8D and they weigh 160 lbs each!
They would measure 21"L x 11"W x 8"H each.

[Davydd]

Rocky,

If they are wet cell batteries you better be checking them. I check mine before heading out for any long trips of a month or more. I estimate I am going to add distilled water about every 15,000 miles of driving and it has been working out that way pretty much. All you need is a Robertson screw driver. It is only four screws per panel and they may be hidden in your carpet if you have the shaggy type. They are not the screws that hold the frame edge in place. It's not a big deal.

Here is one of my batteries.

[Rok]

Davydd,

As always, thank you for the information. I presumed--obviously incorrectly--that these would be the type of battery that didn't need distilled water. We have sealed batteries in all our other rigs, IIRC. I guess that is another thing I will have to do is check the batteries from time to time.

Since we both have GW Legend SE's I bet our batteries are almost identical. If so, then what I have is more like 200 AHs total NOT the 400 AHs we were told.

..........Rocky

[Davydd]

You might have AGM batteries which would mean you would have no need to check them, but I doubt you could have much more than 200 amp hours. You ought to check just to see what you have.

[Rok]

O.K. then, moving onto another subject:

Wi-Fi Boosters.

We've got one. We apparently paid quite a bit to get it, but I don't really know how to use it. I was told that it was only good for "open" wi-fi systems, which would make it pretty useless. What I've found out since is that it is a lot more complex than that.

When we were in the Canadian Rockies about a month ago--we went to Lake Louise, and drove along the Icefields Parkway up to Jasper, etc.--we met another couple who also had a GW Legend SE. And they also had the Wi-Fi Booster in their rig. The other driver, Ken was his name, said that it was the neatest thing since sliced bread.

What a wi-fi booster is, is basically a network inside your van. There is antenna outside to connect to some external wi-fi (with or without a password), and there is also an attenna inside that you can connect all your devices to.

Ken showed me how he was using it. Apparently you first need to connect your computer or phone or pad (he used an I-Pad) to the controller of the Wi-Fi Booster. His I-Pad had an app for that. With the app, he was able to hook up to the external Wi-Fi, like at a campsite, etc., and once that connection was made, he could hook up any devices to the booster directly and the booster would give him connection to the internet for his phones, computers, and even television.

Has anyone else done this?

After returning from our trip, I decided to buy an I-Pad so I could do the same. I've never owned an I-anything, so it will be an experience. Unfortunately, they just came out with a new thinner faster model, so I decided to wait until I could get one of the new ones, or get an old one at a discount.

I'm just wondering if anyone else has experience using a "Wi-Fi Booster"?

Next, I want to know how the "cell phone booster" works, too. So far we haven't noticed any difference when it is on. Does that work somewhat the same? Do we somehow have to connect our phones to it?

Thanks in advance for any replies.

...........Rocky

[Rok]

I will check them Davydd. I should have done it earlier today when I was out there running the engine and propane generator. I'll do it another day. The way we have it parked, there is no access from the back. I'll have to wait a while until I take it our again. The batteries are low (12.3 V), so that should be soon.

Since you are in a helpful mood, Davydd, could you tell me how to upload a photo to the forum? I haven't learned that yet. If I knew that, I could then SHOW you how we park it.



..............Rocky

[Davydd]

I don't have any wifi or cell phone boosters. I'm not sure about wifi. In a campground either the wifi is good or non-existent. If I want wifi I check antenna locations and try to get a site close. Cellular is different. Way too many times the campground is just a tad off the cellular grid and I am sure a booster would make a difference.

[markopolo]

I do that for WiFi in my van Rok. I use a router operating in "Repeater" mode. Some routers have a repeater mode built-in & others can be flashed with third party firmware like DD-WRT. I have a permanent exterior antenna. My setup operates as you describe. I view the router on my iPod and join available networks by selecting "join". I can enter campground password codes into the router via my laptop or iPod for networks that are password protected. The range using the router is much greater than using just the small iPod for example.

The only shortfall with my system is that I can't use the router to join WiFi networks that require you to access their webpage and click OK to accept their terms. That part is disappointing. For example; in Canada Tim Hortons coffee shops offer free WiFi but it only works if you are in the shop or by the door if I'm using my iPod. If I get a coffee at their drive through and then park in their lot my router isn't able to connect to their WiFi because you can only get their WiFi after visiting their webpage and clicking ok to accept their terms.

Other than that, I've found have the extended WiFi range to be a bonus. My laptop will connect to distant WiFi access points but my iPod doesn't. The router sees more networks than the laptop though. Any WiFi device in my van can access the internet through my router when it has connected to an access point.

[markopolo]

Originally Posted by Rok

................... could you tell me how to upload a photo to the forum?............

Here's a "How to post a photo" link Rocky http://www.classbforum.com/phpBB2/vi...php?f=9&t=2537 - it gives you three or four options. I resize the photos I upload to 800x600 size - the forum will take larger photos like 1024x768 but they will fill the screen on some users computers / laptops. The forum doesn't automatically re-size photos. You can upload photos to the forum or link from the forum photo gallery. Davydd uploads his photos to Photobucket.com and displays them here.



the photo will display like this:


There is a forum practice area here: http://www.classbforum.com/phpBB2/viewforum.php?f=30 try as many times as you like. That is what the practice are is for. Once you've done it a few times you'll be a pro!

[Rok]

Thanks Marko,

I'll have to give it a try

[Davydd]

Photobucket gives you a string with the IMG tags so all you have to do is copy and paste. I have pretty much settled on using it for links as it seems to be the easiest to use for me. Most of my photos lately are uploaded directly from my iPhone to Photobucket, Facebook or Twitter.

I did an inventory of my postings of recent times since 2006. I've posted to various message boards over 2,130 photos out of Photobucket alone. More than 1,000 to Facebook and more yet to Twitter. I've used other source reference links as well such as Flickr, MobileMe (now defunct), and Instagram. I uploaded my first image to pre-Internet AOL way back in 1988.