Reply
 
Thread Tools Display Modes
 
Old 07-21-2015, 12:41 PM   #1
Almost There
 
cullengw's Avatar
 
Join Date: May 2015
Location: Chicago, Illinois
Posts: 82
Year: 2002
Coachwork: Navistar
Chassis: International
Engine: Allison
Rated Cap: 60
Question Electrical For Dummies.

Hi all,

I have been reading through some of the Electrical system threads and I notice a lot of high level jargon being tossed around that even I, an electrical engineer minor, cant understand.

I have not worked with electrical circuits like this for 10+ years so I need to understand the basics first.

I know that:

1. I do not want to use the batteries that start the bus to power any appliance that will continue to suck their juice. (maybe I do and I am being paranoid IDK )

2. NOT DOING SOLAR

3. I want to have a primarily AC circuit running off of 12V volt house/deep cycle batteries.

4. I want to be able to charge those batteries with the engine and/or camp-site hook up (which ever makes more sense)

5. Here is a list of what I would be running:
-Mini Fridge
-Laptops charging x4
-Phones charging x4
-A monitor of some sort (for like a back up cam)
-led light strips (hopefully 12V ones)
-Microwave perhaps?
-Reading lights x4
-Throw in another 50W in case i am missing something

6. I want to use a 110V circuit for my AC devices Right?

So really what I want to know is how realistic is this list, how many batteries would I need, what size inverter would I need?

Also if you think I am explaining something wrong, I probably am. I think I will be doing a lot of throughout this thread.

Thank you again for keeping the replies dumbed down
cullengw is offline   Reply With Quote
Old 07-21-2015, 12:48 PM   #2
Bus Crazy
 
M1031A1's Avatar
 
Join Date: Dec 2014
Location: Dowdy Lakes, Colorado
Posts: 1,437
Year: 1989
Coachwork: Thomas
Chassis: Saf-T-Liner ER
Engine: 3208 CAT/MT643 tranny
Rated Cap: 87
Quote:
Originally Posted by cullengw View Post
Thank you again for keeping the replies dumbed down
Don't forget to wet BOTH hands for good contact!!!
__________________
Firearms stand next in importance to the Constitution itself. They are the American people’s liberty teeth and keystone under independence. — George Washington
M1031A1 is offline   Reply With Quote
Old 07-21-2015, 01:19 PM   #3
Bus Crazy
 
turf's Avatar
 
Join Date: Apr 2013
Location: Colorado
Posts: 1,617
Year: 1993
Coachwork: bluebird
Engine: 5.9 Cummins, Allison AT1545
Rated Cap: 2
convert all that into amp hours per day.
decide how long you want to go between recharging.
multiply the first number by the second number.
then double that because you only discharge your batteries half way.
then double that for safety.

eg.........
100 AH per day times 3 days = 300AH times 2 (battery capacity)=600 AH times 2 (safety factor)....... i'd be looking for a bank between 600 and 1200 AH


there are lots of online calculators to help you out.... check out some solar stuff,even though you arent heading that way.... they have the calculators you want.
__________________
.
Turfmobile Build Thread
turf is offline   Reply With Quote
Old 07-21-2015, 02:49 PM   #4
Bus Nut
 
austin1989us's Avatar
 
Join Date: Apr 2015
Location: Tomball, TX
Posts: 313
Year: 1988
Coachwork: Blue Bird
Chassis: TC/2000
Engine: Cummins 5.9TA
Lets say you have an A/C that draws 15A. At 120V, that's 1800W. Lets say your inverter is 90% efficent. That means you'll need to get 2250W out of your 12V battery to give the A/C 1800W. That's 187.5 amps. Say you only wanted to run your A/C for 10 hours before recharging the battery. And, just for fun, lets not have a safety factor. You'll need an 1875 amp-hour battery (like the forklift battery below).

Crown Industrial Battery - 12 Volts, 1875 Amp-hours
austin1989us is offline   Reply With Quote
Old 07-21-2015, 02:54 PM   #5
Bus Crazy
 
roach711's Avatar
 
Join Date: May 2010
Location: Farmington Hills, Mi (Detroit area)
Posts: 1,908
Year: 2000
Coachwork: Eldorado Aerotech 24'
Chassis: Ford E-450 Cutaway Bus
Engine: 7.3L Powerstroke
Rated Cap: 19
Keep in mind that any time you change from DC to AC you lose about 15% of your battery power in the process.

AC to DC uses a Converter.
DC to AC uses an Inverter.

Much will depend on how you'll be using your bus. If you'll mostly be parked with shore power available you'll be able to get by with a much smaller battery bank than if you'll be boondocking for days at a time.
roach711 is offline   Reply With Quote
Old 07-21-2015, 03:20 PM   #6
Almost There
 
ElizaHasAPlan's Avatar
 
Join Date: May 2015
Location: Eastern Kentucky
Posts: 76
Are you forgetting hot water? Water pump? I think you need to be very accurate as far as your needs are concerned. Looking up manufacturer's specs is helpful as well.

Anything that produces heat will be a power hog. Like a hair dryer for instance.

Get yourself a piece of paper, and write every single thing down.
ElizaHasAPlan is offline   Reply With Quote
Old 07-21-2015, 08:31 PM   #7
Almost There
 
cullengw's Avatar
 
Join Date: May 2015
Location: Chicago, Illinois
Posts: 82
Year: 2002
Coachwork: Navistar
Chassis: International
Engine: Allison
Rated Cap: 60
Question

Quote:
Originally Posted by ElizaHasAPlan View Post
Are you forgetting hot water? Water pump? I think you need to be very accurate as far as your needs are concerned. Looking up manufacturer's specs is helpful as well.

Anything that produces heat will be a power hog. Like a hair dryer for instance.

Get yourself a piece of paper, and write every single thing down.
Eliza Thank you for thinking of that, At the moment we will not have a water pump/water heater since there will be no shower/toilet/sink.

As far as the hair dryer and other excessive power consumers like space heaters/air conditioners. I am not going to include those in my plans for now but they are definitely in the back of my mind.

I have been doing research on charging laptops and realized I'm a dope.

Laptop is powered by battery (DC), when you charge it you use an adapter for the (AC) plug. So why would I want to go from a DC battery to an AC inverter to a DC battery again. lol I mean unless certain laptops cant get the dc charging cable.

Thank you all for the feedback and help AH are definitely something I will be adding up over the winter . Question I still have is what is the best way to charge these "accessory" batteries?

Oh and How much does everyone run off their starter batteries?
cullengw is offline   Reply With Quote
Old 07-21-2015, 09:00 PM   #8
Bus Crazy
 
roach711's Avatar
 
Join Date: May 2010
Location: Farmington Hills, Mi (Detroit area)
Posts: 1,908
Year: 2000
Coachwork: Eldorado Aerotech 24'
Chassis: Ford E-450 Cutaway Bus
Engine: 7.3L Powerstroke
Rated Cap: 19
Best to leave the starting batteries to their intended purpose. Starting batteries are meant to output a big slug of energy to start the engine and then be recharged quickly by the alternator. Your deep cycle house batteries are meant to output energy much more slowly over an extended time then be recharged slowly.

You can recharge deep cycles with the alternator, most RVs do just that, but be aware that repeatedly asking an undersized alternator to charge both the starting bank and a large, depleted house bank can cause the alternator to burn out.

Regardless, you'll want some way to disconnect the house bank from the starting bank. A simple manual battery disconnect switch is the simplest solution but requires you to be "the brains".

There are a few options that will "automate" the charging of multiple battery banks but I haven't kept up with the latest technology. Maybe others will chime in.
roach711 is offline   Reply With Quote
Old 07-21-2015, 09:06 PM   #9
Almost There
 
cullengw's Avatar
 
Join Date: May 2015
Location: Chicago, Illinois
Posts: 82
Year: 2002
Coachwork: Navistar
Chassis: International
Engine: Allison
Rated Cap: 60
Alrighty good good ya I am the "electrician of the group" so if the alternator dies its on my dime lol.

Ya I think I will start with ways to charge the batteries and let that determine the number of batteries I get. I know this is me being paranoid again but, if i can help it, After 5-6 hours of continuous use, I wouldn't want my group of batteries to have less than 75-80% used. (This is while driving)

Also another thought, sorry they just keep popping in my head rapid fire and you all are very wise so I want to ask them now .

At an RV campsite with a power hook up.....how does that work :P :P :P do you like hook it up to your batteries? or do you like have a seperate circuit for that?
cullengw is offline   Reply With Quote
Old 07-21-2015, 09:13 PM   #10
Skoolie
 
bubb, the real one's Avatar
 
Join Date: Dec 2014
Location: central texas
Posts: 143
Year: 1990
Coachwork: Thomas/International
Chassis: 3700
Engine: 7.3
Rated Cap: 72
without knowing all the elec requirements I will just talk mostly about the 2 big draws, the fridge and the microwave,
everything but those two items can be handled with 200 to 300 map hours of batteries and a 1000 watt inverter,

amps = watts/volts 1000 watt microwave / 120v = 8.3 amp draw
generally speaking you dont want to draw more than 10% of your battery banks power at any one time so to run a microwave that draws 8 amps you will need a 800ah battery bank, if you go much over the 10% draw the banks voltage will drop and if it drops below about 11v the inverter and the other devices will stop working,

since you will only use the microwave a few minutes per day your 800ah battery bank will be able to handle the rest of your power needs fine, just make sure your fridge does not turn on when the microwave is running,

You really need to test the fridge to see what its actual draw is and how many minutes per 24hrs it runs,

just because of the microwave and the fridge you will want a 2000 watt inverter unless you want a +800 watt bank and dont mind the microwave and fridge running at the same time, depending upon the fridges draw 800ah might not be enough for the fridge/microwaves usage.

you can charge the bank with the bus but it is very inefficient and the alternator is not designed to run for long periods and most important it is not efficient at charging,

you will want a 3 stage charger that does not give more than 10% of the banks capacity in AH, such as a 200ah bank can be charged up to 20amps but not more, check the battery manufacturers web site to confirm this,

make sure your charger is designed for the type of batteries you get such as agm/gel or wet lead acid, dont get a battery that even lists a cca rating since it wont last long,
__________________
my bus thread, https://www.skoolie.net/forums/showthread.php?t=8860&highlight=bubb
bubb, the real one is offline   Reply With Quote
Old 07-21-2015, 09:21 PM   #11
Almost There
 
cullengw's Avatar
 
Join Date: May 2015
Location: Chicago, Illinois
Posts: 82
Year: 2002
Coachwork: Navistar
Chassis: International
Engine: Allison
Rated Cap: 60
Bubb,

Thank you very much, that info is helpful and understandable!!!

I agree with you that the Fridge/microwave are two hurdles to overcome.

It may boil down to me saying "no using the ol' wave when were driving lol.

I remember at a Dorm I lived in they had a mini fridge /microwave combo. It was cool because it had 1 power plug and when you ran the microwave the fridge shut off.

Idk if that would help or not but its at least something. Another question-kind of off topic. Do fridges not consume power 24/7? now that I think about it, it makes sense that fridge would shut off after it reaches a certain temp....huh....well ya learn something new everyday ...... brain is mush, damn alien probes !!!

So for 4 laptops and some led lights (minor items) you think a 250 AH battery hooked up with a 1500-2000 W inverter would be more than enough? and charging wise I should get a converter than gives out no more than 15 amps?
cullengw is offline   Reply With Quote
Old 07-21-2015, 09:35 PM   #12
Bus Crazy
 
roach711's Avatar
 
Join Date: May 2010
Location: Farmington Hills, Mi (Detroit area)
Posts: 1,908
Year: 2000
Coachwork: Eldorado Aerotech 24'
Chassis: Ford E-450 Cutaway Bus
Engine: 7.3L Powerstroke
Rated Cap: 19
Check out the Progressive Dynamics power panels. They have AC breakers and DC fuses along with an AC to DC converter w/three stage battery charger. I've got one and it works great.

PD4045 45 Amp Inteli-Power Mighty Mini Power Center

When you plug into shore power you get 120v power to your AC circuits and the converter gives you DC power to your 12v circuits while charging the battery bank.

Here's a basic wiring diagram

roach711 is offline   Reply With Quote
Old 07-21-2015, 10:22 PM   #13
Skoolie
 
bubb, the real one's Avatar
 
Join Date: Dec 2014
Location: central texas
Posts: 143
Year: 1990
Coachwork: Thomas/International
Chassis: 3700
Engine: 7.3
Rated Cap: 72
to charge the batteries you need a 3 stage battery charger not a converter, it can do more than 15 amps as long as you can change the settings, just in case you start with 2 batteries and then go with more later
__________________
my bus thread, https://www.skoolie.net/forums/showthread.php?t=8860&highlight=bubb
bubb, the real one is offline   Reply With Quote
Old 07-21-2015, 11:38 PM   #14
Bus Crazy
 
Join Date: Jan 2008
Location: Adirondack Mountains NY
Posts: 1,100
Quote:
Originally Posted by cullengw View Post
. . . I have been doing research on charging laptops and realized I'm a dope.

Laptop is powered by battery (DC), when you charge it you use an adapter for the (AC) plug. So why would I want to go from a DC battery to an AC inverter to a DC battery again. lol I mean unless certain laptops cant get the dc charging cable.
Most laptops use about 18 Volts DC out of the adapters to charge the internal batteries, even if the batteries themselves are only 12 Volts. You can get special automotive or airplane DC-DC switching converters to charge them, but they are pricey.

Also, you will find many if not most laptops communicate with their adapters through the power cord. They refuse to work with unknown adapters, even if the voltage and plug are identical. I had one mobile converter stop working years ago when I added a quick-disconnect in the middle of the factory cable from the "brick" to the computer plug, because it impeded the communications transfer embedded in the DC.

I found it was better and much cteaper to get a small inverter just for the correct AC laptop charger, than to get the correct DC-DC charger (unless your employer has a stack of them to hand out ). Just switch the inverter (and all other loads) completely off when not in use, to prevent "phantom loads" from draining your battery.

Example of a phantom load: A TV set that can be turned on by a remote control is always using power to run the sensor that is waiting for the "on" command. To save electricity, plug the set into a power strip and turn the strip off when not in use. Off-grid homesteaders get religiously fanatical about not leaving cell phone chargers plugged into AC when the phone is disconnected, because every little bit of electricity saved is more battery run time.

Quote:
Originally Posted by cullengw View Post
. . . At an RV campsite with a power hook up.....how does that work :P :P :P do you like hook it up to your batteries? or do you like have a seperate circuit for that?
There are AC outlets at campgrounds, you plug your bus into the AC and you provide your own battery charger or "converter" inside the bus.

There are three basic types of campground AC power connections. The first of the two main ones is the "30 amp RV," which is a 3-pin 125-volt connection. It is good for a maximum of 3750 watts. There is a round safety ground, and the hot and neutral are slanted like old dryer or stove outlets.

The second common type at bigger campgrounds is the "50-amp." This is a 125/250 volt four-pin connection. Assuming the receptacle is correctly wired for 250 volts, it can provide 12,500 watts, up to 50 amps on each hot leg. If the outlet happens to be mis-wired with both hot legs on the same phase, cut that in half or else the neutral would be overloaded to 100 amps. Measure each outlet with a meter before plugging in. This style plug has three blades in parallel plus a U-shaped safety ground.

The final type is a 15-amp or 20-amp outlet similar to what you see on the wall at home. The plug with two parallel blades and a ground is for 15 amps. 20-amp plugs and outlets are SUPPOSED to have one blade turned perpendicular to the other, but often 20-amp cords and receptacles will have the common 15-amp parallel blades. Receptacles for 20-amp circuits will sometimes have one T-shaped hole that will take either a 15-amp or 20-amp 125-volt plug.

Campground pedestals may have all three types of outlets present plus a miniature circuit breaker load center built in, or they might be much simpler with only a single choice.

If you limit your bus AC power to 20 amps, and carry a 12/2 shoreline or extension cord with a 15-amp plug on the end, you can plug into any standard outlet, plus you can get a "hockey puck" adapter for a couple of bucks to plug the cord into a 30-amp RV receptacle if that is all their is.

If you are adding an air conditioner or other heavier load, you might install 30-amp service and carry a dedicated 10/2 shoreline. If you are installing dual air conditioners, or using an electric stove, water heater, or hot plate, then you might want to wire for the full 50 amps and carry a heavy 6/3 shoreline.

If you wire for 50 amps and encounter a campground with only 30 amp service, there are pigtail adapters that allow your 4-prong shoreline to plug into a 3-prong socket. Just be sure to turn off breakers for heavy loads, because the outlet is only able to supply 30% of the power the big cord could carry.

Note: If you put in a fuse box or circuit breaker panel, you MUST isolate the white neutral wires in your bus from ground. Neutral is only tied to the safety ground at the main campground or home disconnect, not in your mobile sub-panel. And if you happen to plug into a GFCI ground-fault protected circuit, having the neutral and safety ground tied together will trip the GFCI RIGHT NOW.
__________________
Someone said "Making good decisions comes from experience, experience comes from bad decisions." I say there are three kinds of people: those who learn from their mistakes, those who learn from the mistakes of others, and those who never learn.
Redbear is offline   Reply With Quote
Old 07-22-2015, 09:54 AM   #15
Almost There
 
cullengw's Avatar
 
Join Date: May 2015
Location: Chicago, Illinois
Posts: 82
Year: 2002
Coachwork: Navistar
Chassis: International
Engine: Allison
Rated Cap: 60
Great info thank you very much, I will share this info with the crew and see what option is best for us
cullengw is offline   Reply With Quote
Reply

Tags
appliances, electrical, lighting, power, wiring

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


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 04:23 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
×