Solar for 27" Winnebago

mrmuse

Here's what I have:
27 ft. Winnebago


4 x 100 Watt 12 volt pv
1 20 amp mppt cc upgrade to 60 amp
2 115 ah deep cycle 12 volt
2 x 450 watt power inverters

Max System Voltage (IEC/UL) 1000V / 600V
Maximum Power Pmax 100 Watts (-3%, +3%)
Voltage at Maximum Power Point 18.00 V
Current at Maximum Power Point 5.56 A
Open Circuit Voltage 22.1 V
Short Circuit Current 5.91 A
Module Efficiency 15.7%

4kw Onan genset
1.8 kw backup genset
shore power (if needed)

I need power for:
200 watts LED lighting ??
16,500 btu lp furnace ??
6 gal DSL water heater 1/2 hr day
126 watt 32 in tv 4-5 hrs day
40 watt netbook 10 hrs day

Thoughts and suggestions would be greatly appreciated.
Thanks

BB.

Re: Solar for 27" Winnebago

Welcome to the forum Mr. Muse.

In general, if you want to have long term off grid solar power--You need to look at conservation.

On the AC side, you can get a Kill-a-Watt type meter and measure the load of each appliances. And the meter can be left plugged in for 24 hours or longer and get your average daily load for cycling appliances (refrigerators, laptop computers, etc.).

Your loads you listed so far are "huge" relative to the small size of battery bank/solar array you have. And you should be able to get smaller/more efficient versions of many of your loads.

For example, a net book should average around 20 watts average power. 40 watts during charging. But it is the overall power usage per day that we are worried about:

The TV is another. You can get large LED TVs that that draw ~14-20 watts or so, or about 1/10th that your present TV draws.

126 Watts * 5 hours per day = 630 Watt*Hours per day old TV
14 watts * 5 hours per day = 90 WH per day with new TV

200 Watts of LED lighting... That is a lot of light--Way too much to be "useful" if inside the RV... If you are doing stage lighting, perhaps not enough.

To give you an idea of how I would be designing a long term off grid power system with 2*115 AH @ 12 volt batteries... Nominally, I would suggest 2 days of "storage" and not discharging the batteries below 50% State of charge for long battery life. The average amount of power per day through an AC inverter:

2 * 115 AH * 12 volts * 0.85 inverter efficiency * 1/2 days of storage * 0.50 maximum discharge = 587 WH per day average load for battery bank

Running your present TV at night will consume all of the recommended power from your existing battery bank in two nights of use (assuming stormy weather, little sun, and avoiding generator use).

For RVs that are only used a few weeks a year, you can draw more energy from the battery (2-3 times more) if you recharge fully the next day (driving, generator use next morning, etc.)--The batteries will last a year or two--But given the needs (i.e., a few vacations a year), replacing the batteries every couple of years is probably OK.

Another way of running your battery bank system--Use the genset to power your larger loads, and just you the battery bank for quiet evenings/over night occasional power usage.

So--those minimum loads (radio, small tv, laptop, random task lighting, etc.) would be on your AC inverter+battery bank. And your larger loads (200 watts of LED lighting, present TV) would require shore power/generator usage.

Your thoughts? Energy usage is a highly personal set of choices. And solar power does not generate near as much energy as people think. And if you use the RV during winter in the northern US/Canada, you will harvest very little sun--forcing you to run even more generator time and/or looking for even more conservation measures.

For your DC appliances, you can get small DC AH/WH meters, get a DC current clamp DMM, or even a Battery Monitor to help you measure/plan the loads.

Even an LP heater with a fan can draw a fair amount of power (8 amps or so). Converting to a heater which does no use a fan may be needed for smaller RV/power systems.

-Bill

mrmuse

Re: Solar for 27" Winnebago

Hey Bill,
Thanks for the quick reply. The 32 inch tv is only a couple years old. I do have a 46 inch @246 watts, 22 inch @ about 40 watts, could use the small one.. Misleading LED figures too. I took a 5 meter smd 5050 strip @ 72 watts off 12 volts and made 3 lights for bathroom, over sink, and under cabinet. All are on dimmers running less than 25%. I also replaced 8 fixtures using 1157 bulbs with 20 X 10mm White LED, only specs I could find are here. http://alan-parekh.vstore.ca/white-10mm-18000mcd-p-36.html
Have 5M 5050 RGB SMD LED for "mood" lighting. 5M 5050 RGB SMD LED Waterproof Flexible Strip 300 LEDs + 44 Key IR Remote, Max load current: 2A each color.
Stove, fridge are LP with no elec. usage and very seldom use all the led lights. My figures were for all lights on at the same time, which I doubt will ever happen.
I also plan on adding 4 T105's, 2 250 watt panels with 60 amp mppt cc, but being on fixed income it will take time..Your thoughts??
Gregg (aka mrmuse)

BB.

Re: Solar for 27" Winnebago

Gregg,

Your best bet is to measure actual power usage. Off Grid Solar Power is not cheap. When you add all the costs together (including battery replacement every X years, inverter/charge controllers every ~10+ years, etc.)--You are looking at ~$1-$2+ per kWH (even worse for systems that have seasonal/weekend only use).

So--That 246 Watt TV will cost (very roughly):

• 0.246 KWatts * 5 hours per day * $0.15 per kWH = $0.18 running from utility power per day
• 0.246 KWatts * 5 hours per day * $1.50 per kWH = $1.80 running from off grid solar power per day
• 0.014 KWatts * 5 hours per day * $0.15 per kWH = $0.11 running from off grid solar power per day (new TV)

So--You have a pretty quick model about how much conservation can save you and decide were to put your hard earned savings.

Also be very careful when dealing with Amps (a rate, like gallons per hour) vs Amp*Hours (an amount, like gallons pumped).

2 amps at 12 VDC vs 2 amps at 120 VAC for your LED string:

• 2 amps * 12 VDC = 24 Watt load
• 2 amps * 120 VAC = 240 Watt load

Amps is an "incomplete" unit of "work" and "rate of work". We need to know the voltage too (as well as how many hours per day you will be using the loads).

One reason I like to work with Watts and Watt*Hours--That is a complete unit and we can work on "both sides" of the off grid power system and not get "confused". For example a 24 watt load:

• 24 Watts / 12 VDC = 2 Amp current flow
• 24 Watts / 120 VAC = 0.5 Amp current flow

Note that both are still the same amount of "work"... So solar panel sizing and battery bank sizing is still the same (i.e., two batteries in parallel for 12 volts, or two batteries in series for 24 volt battery bank--They both still store the same amount of energy).

So, two ways we can try to help... One is to suggest you measure all of your loads (AC/DC) and put together a list of loads you want to operate (Watts average, Watt*Hours per day, 120 VAC or 12 VDC loads, etc.). And where your travels will take you and seasons you travel (amount of sunlight available).

Or, we start with a component (such as your two T105 batteries), and design the system/estimate the "useful" amount of power you can get from such a system.

For example, assume a pair of Trojan T105 batteries at 6 volts and 225 AH capacity (20 hour discharge rate). Nominally, you can design for 1-3 days of "no sun storage" and maximum of 50% discharge. If you are doing long term dry camping, I would suggest 2 day of storage--But for RV world (limited storage/weight capacity, 1 day of storage and 80% discharge can be justified seasonal/weekend camping).

• 12 volts * 225 AH * 1/2 days of storage * 0.50 max discharge * 0.85 inverter eff = 574 Watt*Hours per day at 120 VAC nominal loads
• 12 volts * 225 AH * 1/1 day of storage * 0.80 max discharge * 0.85 inverter eff = 1,836 Watt*Hours per day at 120 VAC max not to exceed loads

To recharge such a bank, 5% to 13% rate of charge:

• 12 volts * 225 AH * 1/0.77 panel+controller deratings * 0.05 rate of charge = 175 Watt array minimum
• 12 volts * 225 AH * 1/0.77 panel+controller deratings * 0.10 rate of charge = 351 Watt array nominal
• 12 volts * 225 AH * 1/0.77 panel+controller deratings * 0.13 rate of charge = 456 Watt array "cost effective maximum"

And if you camp in the US South West with lots of sun, you can assume around 4 hours of sun per day minimum for ~9 months of the year. Assuming 400 Watt array:

• 400 Watts * 0.52 end to end system eff * 4 hours of sun per day = 832 Watt*Hours per day of 120 VAC solar power

Your system, as penciled out, seems to be "well balanced"--Now the question is ~832 Watt*Hours per day a "useful" amount of power or not.

Note that this is a really rough number... If you lay your panels flat, do a lot of camping in winter/northern US--You will not get near as much solar power and need to use shore power/generator power more.

If you do need to use the generator more--The 4kW genset is way too large to be very fuel efficient for keeping your battery bank charged and running energy efficient loads... You would do much better (fuel economy, noise) with a Honda (or similar good quality inverter-generator) eu1000i (900 watt) genset and a ~20 amp 12 VDC charger or a eu2000i (1,600 watt) and a ~45 amp 12 VDC charger. Either will probably use 1/2 the amount of gasoline or less vs the 4kWatt genset.

Your thoughts? Your needs?

-Bill

mrmuse

Re: Solar for 27" Winnebago

Hey Bill.
First off, thanks. This is not a pleasure vehicle, it will be my new home. Thanks to a corrupt Disability ALJ I'm on SSI instead of my 43 years of paying into disability. 4 strokes, 2 heart attacks, no left side. Enuff said.
What I'm trying to do is go completely off grid using what I have at hand...Luckily before the strokes I renovated my WinnieBagle. New floors, all new plumbing & fixtures, new furnace, newer water heater, lighting, generator gone through, new roof, new tires, and went through the rooftop A/C. But. I won't be driving it. Just a small piece of property in the boonies.
The Onan runs 2 hrs. per gallon and the 1800 watt about 4 hrs. per gallon. Considering my utility bills now average over $500.00 per month, any alternative is better. The reason for the 32 or 46 inch TV's is near blindness. So you see my situation.
Let's say this. I have the 4 100 watt panels now w/cc and the 2 115 ah batteries and the 2 small msw inverters. If it were you, what would you do?? I have room for 4 more panels and 6 batteries.
Anyone with thoughts/ideas, feel free to chime in. I really need some good advice on this. I really appreciate your time and input.
Gregg

westbranch

Re: Solar for 27" Winnebago

since it looks like you will be stationary, and want to minimize your long term (monthly) cash requirements, if me, I would get 4 more panels, big ones, say 250 W GT types, and mount then on the ground in the OPTIMAL location at the best angle to max out the winter input, get an MPPT Charge controller that can use the 4 existing with the new ones, this may be a tough combo to find/match. May need one more 100w. OR stay as is with the 4 and add the GT's to a new CC all connected to one bank.

Since you want to live a relatively normal life style I would consider getting 4 Golf Car (GC2) batteries. Better for Off Grid type use than 'deep cycle' batts.
Consider a 24 v setup, more $$ now but better long term for amount of daily use you have.

BB.

Re: Solar for 27" Winnebago

Gregg,

That is a tough place you are in now. Dang.

Best I/we can do here is talk through your options and figure out how to reduce your out of pocket as much as practical.

First--The $500 per month utilities... Can you tell us how much of that is electricity?

Generally, Natural Gas/Propane/Electricity usage can be reduced--By upwards of 50% is not impossible (depends on how much conservation you have done to date).

A problem with some utilities now is a major change in the pricing structure for power.

As an example, in Northern California we pay around $4.50 per month for a connection fee (plus a minimal amount of electricity in the monthly bill. Otherwise we pay around $0.13 to upwards of $0.40+ per kWH--So saving on electricity usage can really reduce our bills.

Some companies are starting to reverse the charging basics... Instead charging $40-$90 per month connection charges and $0.06 per kWH for electric power. In that case, no matter how much you save, you still have a $40-$90 per month base bill.

So--How much could you save if you went "off grid" with solar for electricity? Would "conservation" be a good start for you? For the most part, most people's electric costs start with the Fridge/Freezer at around 1-4 kWH per day. And if you have A/C and/or electric heat/hot water, that is what will take you from a $30 per month electric bill to a $100 to $300 per month electric bill.

Insulation, shading windows/building from direct sun can help in the summer--and allowing sun in through windows will help with heating cost in the winter. I.e., conservation and design to use the sun when it makes sense.

If you have high electric charges for heating/hot water--There is a possibility that a mini-split heat pump and a heat pump water heater can save you money/energy.

But you really need to understand your needs. If your hot water usage is only 5 gallons per day--Then installing a heat pump water heater is probably not a good idea. if you have propane or natural gas available, a tank-less water heater may be a better deal.

Modern Heat Pump heating and hot water will be ~2-3 times more efficient than traditional electric resistance heaters--And for water heating, heat pump water heaters sometimes approach the $$$/Gallon water heating costs of Natural Gas.

In general, an off grid power system (say generating 3.3 kWH per day for a "near normal" electric home + refrigerator but natural gas/propane for heating/cooking/hot water) is only ~100 kWH per month or $10-$20 per month in power charges (plus whatever your monthly "meter charge" is).

I don't want to kid you into thinking that off grid power is going to save you money... For most people, it will not. Solar Off Grid power usually only makes sense if your monthly service charge is really high (i.e., only customer at the end of a long run of poles).

For the generators... The 1,800 Generator running about 4 hours per gallon is not bad, if you are using near 1,800 watts. Usually, roughly an 1,800 watt gasoline genset running at 900 watts or less (to zero watts) will use around 50% of full power fuel flow--If yours is running "light loads" and you are getting 4 hours per gallon, an inverter-generator will run about 2x longer running those "light loads".

Many people only use 400 watts +/- on average--And a Honda eu2000i will run around 9+ hours on a gallon of fuel when running these smaller loads (again, measuring your power usage will help you in sizing the system).

And a battery bank+solar is really good for smaller loads... However, you have to look at how many hours per day those loads run.

A microwave may run at 1,500 watts for 20 minutes per day. And a laptop at 40 watts * 12 hours per day:

1,500 watts * 1/3 hours per day = 500 Watt*Hours per day for microwave
40 watt * 12 hours = 460 Watt*Hours per day for laptop
126 watt TV * 5 hours = 630 Watt*Hours per day for TV

So--you can see from a battery+solar panel (or utility billing), the are almost the same power usage for each of your major appliances. A refrigerator may run at 1,000 to 4,000 WH per day (full size refrigerator). And surprisingly, many small "bar/dorm" refrigerators may run 600-800 Watt*Hours per day.

Understanding/measuring your loads and estimating the costs to run them will really help point you to the best solution(s).

Sorry, no easy answers (at least from me).

-Bill

mrmuse

Re: Solar for 27" Winnebago

As for the house, new in 2011: 97% efficient gas furnace, new gas water heater. New insulation, new high efficiency fridge, windows, weather proofing, attic vents. Eliminated the freezer, elec. stove for induction cooktops, one load of laundry twice a month. Switched to CFL's. 2012 switched to all 110 volt LED lighting. Still no drop in elec. Eliminated cable, phone. I've spent over $5500.00 this year already for gas/elec. Filed 3 complaints and no investigator ever showed. Contacted Attorney General, Congressman, and Senator..Nothing. PS, new plumbing, and well pump in 2010. Used the Kill a Watt on everything and still have no clue why..I live with a dog, cat, no supplement elec. heaters and it's only 982 sq. ft.
I'm going crazy..
Gregg
PS Sorry I'm distracted, my Tigers are playin..

Added this: acct. 43 is gas, 018 elec.

54798143 West of Grand Rapids Michigan Sep 24, 2013 $ 8.52
54798143 West of Grand Rapids Michigan Sep 24, 2013 $ 25.57
22666018 West of Grand Rapids Michigan Sep 24, 2013 $ 88.93
22666018 West of Grand Rapids Michigan Sep 24, 2013 $ 266.80
54798143 West of Grand Rapids Michigan Jul 31, 2013 $ 34.09
22666018 West of Grand Rapids Michigan Jul 1, 2013 $ 50.00
54798143 West of Grand Rapids Michigan Jun 28, 2013 $ 265.47
22666018 West of Grand Rapids Michigan Jun 28, 2013 $ 636.13
54798143 West of Grand Rapids Michigan May 28, 2013 $ 255.24
22666018 West of Grand Rapids Michigan May 28, 2013 $ 518.22
22666018 West of Grand Rapids Michigan May 8, 2013 $ 50.00
22666018 West of Grand Rapids Michigan May 8, 2013 $ 75.00
22666018 West of Grand Rapids Michigan Apr 26, 2013 $ 692.76
54798143 West of Grand Rapids Michigan Apr 26, 2013 $ 232.87
54798143 West of Grand Rapids Michigan Mar 27, 2013 $ 194.65
22666018 West of Grand Rapids Michigan Mar 27, 2013 $ 625.88
22666018 West of Grand Rapids Michigan Feb 26, 2013 $ 426.34
54798143 West of Grand Rapids Michigan Feb 26, 2013 $ 141.67
22666018 West of Grand Rapids Michigan Jan 28, 2013 $ 565.62
54798143 West of Grand Rapids Michigan Jan 28, 2013 $ 98.76
54798143 West of Grand Rapids Michigan Dec 27, 2012 $ 62.29

$5314.81
10/07/2013 Current Account Balance: $ 533.28
$5848.09
Average of $584.81 per month for 2013

westbranch

Re: Solar for 27" Winnebago

$5500 so far , wow!
tell us about the well and pressure tank... depth, pump cycle times, HP of pump, brand, etc.

mrmuse

Re: Solar for 27" Winnebago

When I lost my IT job in 2010, I applied through EightCap for weatherproofing, etc. They came out and took the doors off, pressurized the house for air leaks, and everything was repaired/replaced.
Pressurized 5 gal. holding tank, shallow well 42 ft. 1/3 hp well pump might kick in when I shower or do laundry. Every electrical plug is on a power strip and shut down when not in use. As we speak, 3 12 watt leds, tv/sat. rec (total 300watts) and 3 2.5 watt leds in kitchen, my laptop PS says input 1.2 amp/output 20v @3.25 amp. That's in the whole house.

BB.

Re: Solar for 27" Winnebago

Something does not look right--Winter/Summer and variation in billing--Does not make sense.

I am not sure how "electrical aware you are" (I don't want to get you killed or start a fire). I would look at getting a "whole house power monitor". Something like this one has worked well for many folks here:

http://www.theenergydetective.com/5000c

Basically, you just open up your main panel and clip the two current transformers onto the your two Hot Wires from the meter (assuming you have 120/240 VAC split phase power).

Not cheap at $240--And you may find similar units for less... Just an idea.

You can also go back to basics... Older power meters (mechanical) have a rotating disk. It may turn one revolution in 30 seconds and mean you are using 100 Watts of power (need numbers from your meter to know conversion factors).

You can also go to your main panel and turn off all power. Make sure meter stops. Then turn on one circuit at a time and watch the meter. If you have everything turned off, the disk should not turn (or barely creep forward--taking minutes to make a whole revolution).

If the disk turns and everything is "off"--Then you have a load somewhere you don't know about. I have seen meters that were miss-wired by an electrician or in once case, were an apartment building need some power for garage door and landscape lighting. In another case, the A/C system for a computer room was connected to the next door business' meter.

Lastly, check the tag/id on the meter and see if it matches that on your bill. Also, check the numbers on the bill... It should the actual numbers from your meter:

35,423 this month
34,400 last month (subtract)

---

1,023 kWH used

Also, if you can take a recent bill and type in the basic information:

$4.40 per month metering charge
1,023 kWH billing period
$0.12 per kWH

Etc.... (note, billing can be a lot more complex, tiered usage, time of day, seasonal, etc.)

In some cases, a utility will estimate power usage (i.e., missed readings or readings every several months in remote areas, etc.) and when a "real reading" is made, a dramatic upwards or downwards swing on the bill. Some utiltities will "average bills" too (i.e., lower summer A/C bill peaks, raise spring/fall bills to pay for summer).

-Bill

BB.

Re: Solar for 27" Winnebago

So, just a SWAG:

0.300 kWatts * 24 hours per day * 30 days per month = 216 kWH per month

That should be a $30-$50 monthly bill in most areas (or a bit more).

I have suggested people turn off their main breaker over night and see what happens. One person here (as I recall) had the landlord come up and ask if the tenant was having power problems "too" (main house was partially powered by tenant's meter--Or billing id/meter tags were reversed between tenant and main home--something like that).

You can also, when your home's loads are shutdown--Get a 1,500 watt heater, plug it in and turn it one. In about 40 minutes, the meter should have advanced 1 kWH (and you can count disk rotations per minute, or seconds per disk rotation).

I actually read this was how a Utility person actually measured the accuracy of a meter in dispute--Simple turned off all power, plugged in a couple of space heaters (with know wattage load) and waited an hour or two--and read the meter (we had lots of folks complaining in California when the utility when to "smart" digital meters).

There were some problems with smart meters when they first came out (and even billing issues with remote read meters)--But the vast majority appeared to be operating correctly.

-Bill

mrmuse

Re: Solar for 27" Winnebago

Funny you should mention digital, and remote reading. That is when the problems started Also, I've lived here since 97, but heated with wood until 2008.Attachment not found.

EST Oct 2, 2013 18176
ACT Sep 3, 2013 17590
ACT Aug 2, 2013 16301
ACT Jul 5, 2013 15286
ACT Jun 8, 2013 14550
ACT Jun 6, 2013 14550
ACT Jun 4, 2013 14516
ACT May 3, 2013 13758
ACT Apr 17, 2013 13239
ACT Apr 17, 2013 13239
ACT Apr 3, 2013 12687
ACT Mar 4, 2013 11395
ACT Feb 1, 2013 09855
ACT Jan 4, 2013 08322
ACT Dec 3, 2012 06637
ACT Oct 30, 2012 05289

BB.

Re: Solar for 27" Winnebago

1,289 kWH per month * 1,000 WH/kWH * 1/30 days per month * 1/24 hours per day = 1,790 Watt average load 24x7x30

Basically a 1,500 watt heater and your well pump running 24 hours per day for August...

That is a lot of power.

The T.E.D. or similar--You really need to figure out what is going on.

If you were averaging 300 kWH per month--I would be surprised--But it does depend on your other electrical loads/irrigation (if any/etc.).

Have you matched the Meter Reading to what you see on your Bill?

-Bill

mrmuse

Re: Solar for 27" Winnebago

I called in a meter read from 10/01-10/07. This is 6 days, but it has the rates.

Attachment not found.

mrmuse

Re: Solar for 27" Winnebago

Let's get back to a totally off grid solar system for the Winnie. I can't make sense of the utility bills because they are so inconsistent.

Gregg

BB.

Re: Solar for 27" Winnebago

Works out to about $0.133 per kWH... Pretty reasonable rate.

However, the second reading on your bill said (estimate)--That should be a red flag. They don't have a "real" reading.

I would try to match what you see on your bill (meter ID, numbers on bill, etc.) to what you see on the face of your meter. If you cannot match the ID and/or the numbers on your bill to the meter (i.e., the meter reading should be your last billing+kWH used in the next period)--Something is wrong.

If you are in a poor area for meters that are remote read (central tower, power line, truck with antenna/computer)--Some of the original computer software for our utility would take a "bad reading" (i.e., 10x larger reading from corrupted transfer), the next reading was supposed to "correct" the bad "difference"... It did not.

Something looks strange.

-Bill

mrmuse

Re: Solar for 27" Winnebago

None of it makes sense. I just want to go solar and eliminate them
Gregg

westbranch

Re: Solar for 27" Winnebago

To give you a reference point, our Hydro elec. bill is about 20 - 21 KWh per day all year long...

we run 2 fridges, 2 freezers, an elec stove and a 3/4 hp well pump in a 300 foot well. gas furnace.

Something is seriously wrong.

Do you know if your pump ever shuts off?

As Bill suggested, throw the main breaker and all other breakers for an hour and see if there is a 'phantom load'... the reset the main breaker and wait another hour. then test wach circuit separately. this may take a couple of days if you don.t see one ' blast off from the gate' ...

Good hunting.

mrmuse

Re: Solar for 27" Winnebago

The pump is under my kitchen. Hardly runs, I can hear it kick in and out. I can't test the digital meter that way as it draws power to run itself, so there is always a load on it. That is why I filed 3 complaints. To get THEM to come out and determine the cause.

Gregg

BB.

Re: Solar for 27" Winnebago

The digital meter should only draw a few watts. Say the meter draws 5 watts:

5 watts * 24 hours per day * 1/30 days per month * 1kW/1,000W = 3.6 kWH per month

The self power from the meter should not be noticeable in your inspection of your home.

For example, most meters (mechanical dial, and LCD Bar) have a rotating disk (or flashing LEC bar) that you can time... Say it takes 30 seconds for one "rotation", you then divide that into time and multiply by a conversion factor for your meter.

Take the Kh number on the face of the meter and:

• Kh * 3,600 sec/hour / (# of seconds for 1 revolution of meter "dial") = watts

(Kh is the watt*hours per revolution)

Example with Kh=12 WH/Rev and Time = 28 seconds per revolution

• 12 wh/rev * 3,600 sec/hour / 28 second per 1 revolution = 1,543 Watts

Your "Kh" number may be 12 or it may be some other number.

At least this way, you can estimate your power usage in a few minutes or less. In my example, a 5 watt load will turn a 12 Watt*Hour/Rev disk one revolution in:

• 12 WH per rev / 5 watt load = 2.4 hour per revolution

The digital meters out here will display the kWH, voltage, and current Watt draw (i.e., 0.30 = 300 watt load).

http://www.pge.com/en/myhome/customerservice/smartmeter/reading/index.page

-Bill

solar_dave

Re: Solar for 27" Winnebago

Something certainly doesn't sound right there, just as a reference I have a buddy in Marne, MI using propane for heat and his electric bill is about $100 a month. Now his propane bill is another story.

Here we use 25-35 kWh a day in the main house when not running the heat pumps, that include 3.5 hours of pool pump, a freezer and large late model fridge, electric laundry, Dish washer, CFL & LED lighting with 2 100 watt equivalent CFLs on over night, typical TV, Stereo, 2 computers, phone system with 3 remotes, 2 MAC mini computers and all the charging stuff iPods, iPads, Cell phone ...

The TED mention can be really valuable in tracking down power hogs.

BB.

Re: Solar for 27" Winnebago

And the TED should be accurate enough for you to have a good case to get the power company to review their billing/meter.

Also, if you have access to the meter drop (the two hots and neutral to the weather head on your roof)--You can use an AC Current Clamp meter to measure current flow too--That will allow you to estimate the power before the meter--And you can verify if you have an energy leak somewhere.

Note that measuring current with an AC current clamp meter will overestimate your energy usage because you are not measuring current phase vs voltage... But that is OK for this setup. If the meter reads significantly more than you estimate--another indication of problems.

-Bill

mrmuse

Re: Solar for 27" Winnebago

Is this TED? I can hook this to my laptop/netbook? http://www.ebay.com/itm/TED-5000-G-Series-The-Energy-Detective-Kill-A-Watt-Home-Energy-Power-Monitor-/290928960966?pt=LH_DefaultDomain_0&var=&hash=item43bcb7a5c6

Gregg

BB.

Re: Solar for 27" Winnebago

look at solar Dave signature above, he has a Ted 5000 connected to his network.

-Bill

mrmuse

Re: Solar for 27" Winnebago

I did, link kept timing out..

solar_dave

Re: Solar for 27" Winnebago

Yeah the dynamic IP service pretty much sucks, try http://98.177.180.206:8081

solar_dave

Re: Solar for 27" Winnebago

mrmuse wrote: »

Is this TED? I can hook this to my laptop/netbook? http://www.ebay.com/itm/TED-5000-G-Series-The-Energy-Detective-Kill-A-Watt-Home-Energy-Power-Monitor-/290928960966?pt=LH_DefaultDomain_0&var=&hash=item43bcb7a5c6

Gregg

That looks like a single MTU unit and can measure a single line by moving the CT around in the box or overall usage if the CT are snapped around the mains. You can order them with up to 4 MTU/CT measuring devices to get a better picture. Be aware it uses power line comms, and can be a bit finicky about the setup and line the MTU is wired on. I hooked my gateway (appliance device) up to an outlet near my power panel and used a WiFi client device (Model No. TL-WR700N) to make the transition to my network instead of stringing a long cat 5 run.

PS don't hook it up to a plug strip, wall outlet for the gateway only.