(she is car camping in Erhenburg)

I've been following this awesome lady..first from the other forum, then her videos. WOW what an inspiration she is!

here is her youtube channel


and here's her account on other forum
http://www.cheaprvliving.com/forums/User-KiaGypsyGirl


I'm sending her an invite 

Simple Electrical Math
 
POWER is measured in WATTS.  It’s named after the Scottish inventor James Watt, and it originally was used for measuring the power of steam engines.
For Electrical Power, 1 watt is defined as the amount of work done by 1 ampere of current, driven by 1 volt of electrical pressure.
Or as we’d write it as a simple math expression, 1W = 1A x 1V.

(I will mention in passing, that there is no difference between AC and DC, as long as we are talking about simple electrical stuff like electric heaters and motors and light bulbs.  When dealing with electronics, something else called REACTANCE comes into play with AC electricity, and there they talk about Volt-Amps instead of Watts.  You might see volt-amps mentioned on computer power supply bricks, for example.  The difference between watts and volt-amps is something only electronics engineers need to worry about, and we can ignore it.)

Now, obviously, if W = A x V, then 12 volts x 1 amp = 12 watts.  And 6 volts x 2 amps also = 12 watts.  This explains why the battery cables on the old 6 volt cars were much thicker than the battery cables on 12 volt cars.  They need to carry twice the current to produce the same power.

This also explains why the wires carrying DC power going into an inverter have to be MUCH thicker than the AC wires coming out of it.  If you want 1,000 watts of power out of the inverter, you need to take 1,000 watts of power out of the battery.  The inverter merely changes the power from DC to AC, and from 12 volts to 120 volts.  (We’re ignoring real-world internal losses in the inverter due to resistance and other factors like that pesky reactance.)

Let’s run the numbers.  Back in 9th grade math class, we learned that we could manipulate a simple formula like W = A x V to make it easy to find the unknown quantity if we knew any two values.  If W = A x V, then A = W / V, or V = W / A.

So 1,000 watts / 12 volts = 83.33 amps.  Whereas 1,000 watts / 120 volts = 8.33 amps.  This tells us that the inverter is going to draw 83 amps of current out of the battery at 12 volts, in order to send 8.3 amps of current out at 120 volts.

Notice that there is a 10 to 1 relationship between 120 and 12?  That gives us a simple, handy rule of thumb.  If the power supply on a computer or television or anything else lists how many amps of 120 volt AC it is going to use, we know that it will take 10 times as much DC current from the battery to run it with an inverter.  We don't even have to reach for our calculator.

Now, both Amps and Watts are instantaneous values.  That inverter is drawing 83.33 Amps of current RIGHT NOW.  It’s drawing 1,000 Watts of power RIGHT NOW.  Turn the inverter off, and current and power immediately stop flowing.  Neither Amps nor Watts is a QUANTITY in the same way that Gallons is.  Take 1 gallon of gasoline out of a fuel tank, and we all understand what that means.  A little economy car puttering around town may use half a gallon per hour, and a Nascar racer screaming around Daytona at 200 mph may be burning 5 gallons per hour.  So gallons is a quantity, and gallons per hour (gph) is a RATE.

Likewise, Amps and Watts can be thought of as Rates.  We are removing power from our battery at a RATE of 1,000 Watts or 83.33 Amps. For Quantity, we need to be talking about Amp-Hours or Watt-Hours.

 As discussed in another post in this series, the Quantity of electricity “stored” in a battery is measured in Amp-Hours.  If we left that inverter running for an hour, drawing 83.33 Amps, we would use 83.33 Amp-Hours.  Or, since it’s drawing 1,000 Watts, 1,000 Watt-Hours.

But since battery capacity is almost always specified in Amp-Hours, we’ll mostly stick to using that here.  (But note that 1,000 Watt-Hours is also called a Kilo-Watt-Hour – from kilo being the metric term for 1,000 – and your utility charges you by the KWH for the AC electricity you buy from them.)

We rarely run something like a microwave oven for a whole hour.  Here’s a trick for calculating Amp-Hours when you are measuring time in minutes instead of hours.

Because 1 hour contains 60 minutes, if we divide 1 by 60, we get 0.016.  In other words, each minute is .016th of an hour.  If we put a cup of coffee in our microwave to reheat, and it draws 83.33 Amps of current, that’s 83.33 x .016 = 1.33.  In other words, even though the inverter was pulling 83.33 Amps of current out of the house battery to power a 1,000 Watt microwave, we only pulled 1.33 Amp-Hours out of our battery bank to re-heat that coffee.

I hope that sheds some light on Volts, Amps, Watts, and Amp-Hours; and how they relate to each other.  Once you understand them, it’s easy to use a calculator to juggle the numbers around to make sense or it all.

Of course, the real world is never as neat as the mathematical one.  There’s inverter efficiency and something called “Peukert’s Law”, which we’ll get to another time, which prevents us from actually getting these mathematical ideals.  But it’s usually close enough for government work, as they say. Especially if we are talking about small numbers, like lights or a fan would draw, instead of large numbers like an inverter would draw.

And for the most part the damn thing is still running,further more there are people using it
the usual amount of computer bugs but computers suck like that 

contacted the host about bandwidth and such,they came back with this

'Hello Gary,

We do not have any pre-configured disk or bandwidth limits on your account. Having reviewed your account just now, you are well below the average disk usage of an account on our services. Your bandwidth usage is also fine.

Please let us know if you have any questions."

 

so it looks like we are good to go,if you have any issues or problem contact rvpopeye

Is there some way that I can set my account so I DO NOT receive e-mail notifications?  Yes, I know I can click the box at the bottom when I post a response, but I almost always forget.  A.D.D., you know.  The other forum had it set so you automatically DIDN'T subscribe unless you marked it.  At least, when they had it -- I think it's turned off, now.

SO I Spent 2.5 hours typing up and editing and clarifying  a battery charging turorial for the useful information subforum, clicked submit, and then the spinning circle spun and spun, I went to highlight and copy all the text, but got the 
'Site too too long to respond message'

fast internet connection.  every other  site wors normally

Back button nothing, forward button nothing.  All those words gone.
  2.5 hours wasted.


Obviously should have typed in a wordprocessor instead or copied all text before clicking submit, but I will shake my fist at the sky, curse loudly, and smash somthing into little undiscernable bits tomorrow.

the attachment have a different setting for all the different file types and use the sites bandwidth/storage to save them so a .jpeg you can go xxx size but a .png you can only go xxx size and so on

if possible use a photo hosting site like imgur.com or the like and you will have no problem posting photos and not use the forums bandwidth to store them here

i did contact the host and they say we are fine on bandwidth

Got an email today from Matt (Everyroadleadshome) telling me about the new forum.  Good to see all the familiar faces.  I'm back in Mass after my initial 6 month exploratory trip out West.  Going to be static at least until S.S. kicks in an 14 months or so and then I'll be full timing until......I croak, hopefully.

Some goals for the next 14 months: to get my tax mess straightened up and get a passport so I can do some Mexico travel, and of course build my savings account back up.


In the meantime I'm planning my next build.  The 6x10 utility worked great, but I'm leaning towards either a small bus (a shorty International skoolie would be my dream home) or perhaps even an ambulance. At any rate, I've been feeling pretty homesick for the road since I got back, so there's no question it's going to happen. But my last trip gave me some good insight as to how I'll be doing it next time.

Looking forward to lurking and picking up tips.

Thanks

Wire Sizes and Fusing:
 
There is a maximum amount of current that each size wire can carry safely before suffering either long term, or in some cases RAPID deterioration.
 
The technical term for this is its AMPACITY, which is a made-up term from the two words Ampere Capacity.
 
In addition to wire size, it is also partially dependent on the temperature rating of the insulation on the wire.  Wire with insulation rated for 90 degrees Celsius has a higher ampacity rating than the same size wire with insulation rated for 60 degrees Celsius does.  Bundling a bunch of wires together calls for de-rating the ampacity, because the wires in the center of the bundle can’t shed heat like they could if they were run singly.

The length of the wire also affects how much current a wire can safely carry,  Every size wire has a certain amount of electrical resistance PER FOOT, and the more feet of wire there is, the more the resistance adds up.  More resistance causes the voltage to drop.  In simple terms, here's how that works:

Every device - fan, light, water pump, refrigerator, etc. need a certain amount of power to run.  That power is expressed in WATTS.  Now watts is simply the voltage times the amperage.  If you had a fan that needed 100 watts to run, a fully charged battery, at 12.6 volts, would need to provide 7.93 amps.  (100 / 12.6 = 7.93)  If you'd already used a lot of power, and the battery only had 12.2 volts, that would be 100 / 12.2 = 8.19 amps

Now, if your fan were located 1 foot away from your 12.6 volt battery, it would probably see all 12.6 volts, and it would draw 7.93 amps.  If it were 100 feet away, the resistance in the wire might cause enough voltage drop that - even though the battery were at 12.6 volts, the fan would only see 12.2 volts, and hence would draw 8.19 amps instead of 7.93 amps.

Now, admittedly, the difference between 8.19 and 7.93 is really not all that significant.  But where this principle really comes into play is when you are wiring up items like large inverters or 12 volt fridges.  Resistance and voltage drop are the reasons that you always keep the wires between the battery and the inverter as short as possible, and use as big a wire as possible.  There is a hell of a difference between a 3 foot section of 2/0 cable and a 10 foot section of 2 gauge cable.

But as a practical matter, the distance inside our vans is small enough that we can usually just ignore the voltage drop tables. 

I personally would just use 12 gauge wire for almost everything (except inverters, solar panel controllers and battery chargers) and not worry about the length or the resistance.
 
Anyway here’s a simple table of fuse sizes matched to wire gauge size that’s close enough for government work, as they say.
 
For 14 gauge wire, it’s 15 amps
For 12 gauge wire it’s 20 amps
For 10 gauge wire it’s 30 amps
For 8 gauge wire it’s 50 amps
For 6 gauge wire it’s 80 amps
For 4 gauge wire it’s 125 amps
For 2 gauge wire it’s 200 amps
For 1 gauge wire, it’s 250 amps
For 1/0 gauge wire it’s 325 amps
For 2/0 gauge wire it’s 400 amps
 
You can ALWAYS put a smaller fuse on a wire safely.  For instance, If I were installing a 12 volt fuse block for my house circuits, and it was rated fora maximum of 100 amps, I would run 4 gauge wire(125 amps) from the battery to the fuse block, and fuse it close to the battery with a 100 amp fuse.

That said, it's almost always best to fuse a wire with the max fuse for that wire.  In most cases, the fuse is there to protect the wire, and not the item it is powering.
If you have a 12 gauge wire going to a radio that has a built in 3 amp fuse, the 3 amp fuse is there to protect the RADIO from too much current.  You would still put a 20 amp fuse on the positive wire.  That's there to keep the wire from overheating and starting a fire if the insulation on it were to become damaged and the wire were to short against the chassis.  In that case, the wire would draw LARGE amounts of current, and the resistance would cause it to get Red Hot VERY quickly.  With a fused wire, the fuse blows and shuts it down before that can happen.

You could, of course, fuse that wire with a 3 amp fuse, or even an intermediate fuse like 5 or 10 amps.  But fuses have electrical resistance, too, and the larger the fuse, the less resistance there is.  Plus, it makes it easy to add other items to the same circuit in the future.

There are regular fuses, fast blow fuses, and slow blow fuses.  Most fuses are regular fuses, and they are perfectly adequate for protecting wire from short circuits.  Fast blow fuses are used to protect electronic units like radios, etc.  While a regular fuse would blow, it would allow enough dangerously high current to flow long enough to damage delicate internal electronic components.  Slow blow fuses are used on circuits with electric motors.  Because of inertia, starting a stopped motor turning requires more current than it needs to keep running after it's already turning at speed.  A motor, on startup, can draw two or three times as much current as it needs when it is running.  A slow blow fuse tolerates that short term high current, but will still blow if the high current goes on too long.

Battery Basics

We’re going to discuss conventional Lead-Acid batteries.  More exotic stuff like Lithium batteries will need a different post from someone who knows more about them than I do.
 
First, let’s talk about cycles.  You start out with a fully charged battery, you run various stuff – lights, fans, a 12 volt fridge, maybe recharge a laptop computer – and eventually you notice that it’s getting low, so you recharge it.
 
THAT is one cycle, from charged to discharged, back to fully charged.
 
Hold that thought – we’ll come back to it.
 
Lead-acid chemistry cells each produce 2.1 volts.  So a 12 volt battery has 6 of those cells, and a nominal “12 volt battery” is actually 12.6 volts or a fraction more when it is fully charged.
 
Moreover, in order to recharge a battery, the charging source – a battery charger, the vehicle alternator, a solar panel controller – must be at a HIGHER voltage in order to force electrons back into the cells. Most of them operate at 13 to 15 volts.  So “12 volt stuff” – lights, fans, etc. are actually designed to run on anything from about 10.5 volts to about 15 volts.
 
Regular lead-acid batteries have liquid acid in them.  They are often referred to as Flooded Lead Acid or FLA for short.  There are three types of them.
 
Regular car batteries are sometimes called “engine batteries” or “starter batteries” or “Starter-Lights-Ignition (SLI for short)”.

Because the starter needs a lot of amps for a very short period of time, they are designed with many thin plates in each cell.  The idea is to MAXIMIZE the amount of surface area of lead exposed to acid.  This maximizes the amount of amps the cell can provide to the starter when you turn the key.

(Surface area controls the amount of amps, the chemistry controls the amount of volts, the fully charged cell will always be 2.1 volts regardless of how thick or thin the plates are.)
 
Starter batteries are rated by something called Cold Cranking Amps (CCA). This is the number of amps it can deliver at 0 degrees Fahrenheit.  The higher the CCA rating, the more likely it is to start your car when it gets really cold out.
 
BTW, diesel engines, because of their much higher compression compared to gasoline engines, require a LOT more amps to power their starters, so much so that most diesel trucks have TWO batteries wired together in parallel to double the CCA available to their starter.
 
We are not interested in Cold Cranking Amps on house batteries, we are interested in how much total power we can get out of it, which is something called “Amp-Hours”.  Amp-hours can be measured at different current rates, but we are interested in the industry standard, which is the 20 hour rate.  If a battery can deliver 5 amps for 20 hours before it is discharged, it is said to contain (5 X 20 = 100) 100 amp hours.
 
Now, once your engine starts, the alternator immediately begins powering the ignition, lights, radio and everything else as well as recharging the starting battery.  Ordinarily, it would not use more than 5 to 10 percent of it’s capacity before the alternator recharges it, and it can survive thousands of these 10% duty cycles.  But if you discharged it down to 50% every time before recharging it, it would only survive about 40 or 50 of such cycles.
 
True story:  I once had a landlord who worked nights at a place only a few miles away from his house.  His wife drove the “good” car and he drove an old beater back and forth to work.  His alternator died, but he had access to a garage with an outlet where he worked, so rather than buy a new alternator, he decided to drive to work and plug his car into a battery charger for eight hours.  Next morning, he’d drive home and plug it back into the charger until it was time to go to work again.
 
His battery lasted a little less than a month before it was completely dead.  Driving at night, with the lights on, he probably pulled the battery down to 50% or less every cycle.
 
Now, TRUE Deep-Cycle Batteries – such as are used in Golf Carts and industrial equipment like pallet trucks and floor sweepers, are designed with extremely heavy, THICK lead plates.  You will probably not get as many amps out of each cell as you will from a starter battery.  But what you will get is cycles.  On a 50% cycle, you will get anywhere from 1,000 to 1,500 cycles out of these bruisers.  If you are only pulling them down to 60 to 70 percent, it may well exceed 2,000 cycles.

Notice that I said that you probably won’t get as many amps out of each cell.  But if the battery were physically big enough so that as many square inches of the much thicker lead plates would be exposed to the acid, you would get that many amps.  But the battery would be a lot bigger, a lot heavier, would have a lot more lead in it, and would therefor cost a lot more money than a starter battery would.
 
But for house batteries, we’re not - usually - interested in drawing large amounts of current (amps) out of it.  But if we were trying to power a large inverter, say 1500, 2000, or even more watts, that WOULD require a lot of current, and it would need it for a lot more time than the 20 seconds or so that a starter draws a lot of current.  So for that, you need a large battery bank – lots of batteries – or the large inverter will cause the battery’s voltage to drop WAY down, and the inverter will shut down due to insufficient voltage.
 
Anyway, we need to keep in mind that we’re not usually concerned so much with amps as we are with amp-hours.  The thing to keep in mind is that we DON”T want to draw the battery down below 50%, because even deep cycle batteries will fail quickly if they are drained too much.  Run them down to only 20% every cycle (That is, use 80% of their stored power) and you may only get 100 cycles or less out of them.
 
The take away here is that if the battery says it holds 100 amp-hours, it really means there are only 50 USEABLE amp-hours in it.  So if we need to use 100 amp-hours every day, we need a battery bank with two or three 100 amp-hour batteries in it.
 
Now let’s talk about the third kind of FLA battery, the Marine/RV “deep-cycle” battery.  This is not a TRUE deep-cycle battery.  It is a hybrid battery, midway between a real deep-cycle and a starter battery.

It was originally developed for boats.  They not only need to start their engines, but if they are anchoring somewhere instead of being tied up at a dock, they are required by law to run certain bright “anchor lights” at night, all night long, to avoid collisions with other boats. So they needed batteries that could stand being discharged a lot more than the 10% that starter batteries are designed for.
 
The commercial motor home and trailer manufacturers use these batteries because they are a lot cheaper than the true deep-cycles.  They are usually good for 400 ton 500 cycles.  The average new RV buyer doesn’t know any better, and by the time these “RV” batteries die, the smarter RV owners will replace them with golf cart batteries, which ARE true deep-cycle batteries.

If you were running a minimalist setup, only running a few LED lights at night and recharging a phone and a laptop, and you wanted to get away from having a separate house battery, you could replace your starter battery with one of these marine/rv batteries and get a lot more life from it than the starter battery would provide.  But carry a jumper pack just in case.
 
In addition to FLOODED lead acid batteries, there are also GEL batteries and AGM batteries.
 
GEL batteries have the acid between the plates suspended in a gelatin. They are very expensive, compared to FLA batteries. They are also very finicky about how you charge them, and you can damage them or even destroy them if you charge them wrong.  They are still used in certain specialized fields, but they really have no place in our world.
 
AGM stands for Absorbed Glass Mat.  These batteries were developed to be a better replacement for the GEL batteries.  Instead of liquid acid, a fiberglass screen (the Glass Mat) soaked in acid is held tightly in place between the lead plates.
 
Like the GEL batteries, it is a sealed battery that cannot leak, and it can be mounted sideways as well as the more usual way if it will fit better like that.  It’s being used more and more in commercial RVs, especially truck campers, because the designers can bury them down in nooks and crannies that are almost unreachable.  They require almost no routine maintenance and you don’t have to check the cells or add distilled water like you do the flooded batteries.  They are also very
rugged.  The 4X4 crowd loves them because they can survive shaking on rough terrain that would damage the plates on regular FLA batteries.

There is really no practical distinction between starter and deep-cycle in the AGM world.  Their only disadvantage is that they are more expensive than Flooded Deep-Cycle batteries.
 
If money is really tight, you will get the most bang for your buck by buying golf cart batteries from Costco or Sam’s Club.

I want to close by mentioning that, while we talk about "storage" batteries as if they were tanks that simply held electricity, they are actually chemical generators. They use a chemical reaction to produce electricity when you are discharging them, and recharging them cause a reverse chemical reaction to occur that restores them to their original chemical condition.

If we had a 10 gallon fuel tank, and we used 5 gallons from it, we know that if we put 5 gallons back in, it would be full again.

But with batteries, if you pull 50 amp-hours out, you have to put more than 50 amp-hours back in in order to reverse the chemical action.  On average, it takes about 110% of what you take out of a battery to bring it fully back to charge.  So your solar panels would have to be capable of producing a bit more power than you actually use, in order to keep up with it.

I asked Sternwake to review the above info, and he very kindly looked it over and provided the following clarifications to what I wrote:
 
"I would just clarify that very few engines will require 10% of the battery capacity to start the engine.
 
It takes mine about 45 seconds  after starting, at 14.7v before amps taper to the same level as before engine starting, Indicating what was used to start the engine was replenished, but mine starts very quickly, A carb'd engine or a diesel would require more of the battery to start and more time to replenish what was used to start the engine.  But by and large the amount of capacity used to start the engine is very very little, especially with fuel injected vehicles.
 
A fully charged but degraded battery which could not otherwise recharge a smart phone 3 times in a row, could likely start an engine in mild to warm temperatures.   I had one such battery and was amazed that it kept on keeping on and I wound up replacing it before it got to the point it could not.
 
Also, the amount of cycles to be expected, well the 1200 to 1500 cycles to 50% is considering a perfect full recharge each cycle.  A 'Lab' cycle pretty much never occurs in this lifestyle, as getting those last few % in takes so freaking long, and those last few % are so damn important if one wants to get the most from their lead acid batteries.  Regarding the recharging of lead acid batteries, 98% is good, but only half as good as 100% and so many automatic charging sources just shrug in the 95% range and throw the lying SOB green light.
 
Also while AGMS do blur the line between starting and deep cycle, the Lifeline cannot be compared to the Deka intimidator in the same deep cycle usage.  The Deka would be hard pressed to get 350 deep cycles in the same regiment where the Lifeline could get 1000+.  The Lifeline costs about 80% more but if treated right can last 200% more cycles.
 
But both,if treated poorly with chronic undercharging, will last about the same.
 
Also the AGMS are more likely to degrade faster than flooded when often not recharged to full. The flooded batteries can be equalized to dissolve the sulfation, the AGMS besides lifeline 'should' not be equalized.  The AGM should also have higher charge currents initially appled every so often  when they are deeply drawn down.  They are kind of a princess battery that is not suited to a deep discharge  followed by a low and slow solar only recharge regimen, where a golf cart battery
could handle that duty much better for much less $$."

Just joined and notice that I can't scroll with the cursor arrow keys.  PageUP or PageDN don't work either. Anyone else have that problem?  I'm using Firefox.