Continuing Solar build for RV.

Nvreloader · November 2014

After 4 yrs of Attempting to get my head wrapped around this solar info,
I will try again, so here it goes.

Section #1,
Here is what I want to do,
Build/install a RELIABLE solar system for my RV, 28' Desert Fox TH.
This solar build/install is MAINLEY for use during the cold winter months, when we must depend on it, temps range from -20F to 40*f average,
can vary greatly depending on the year?

As I found out in the past 4 yrs of use, of strictly BOONDOCKING only, (I don't do camp grounds),the furnance creates the BIGGEST problem, on battery usage, 2 tongue batties are not enough to get thru the night, even when the thermastat is set to 55* (lowest setting possible).
This thermastat will be changed out for the digital type which can be set lower.

Have an onboard 4000 Gen Set, it is run an average of 4-5 hrs p/night now, BUT don't like or want to use it, unless there is NO other option, (reason for the solar build). I want peace and quite, when ever possible.

Have a OEM Progressive 6290 invertor/charger installed, for the 2-12v tongue batteries.

Section #2
Changes and upgrades done so far.

Have changed ALL RV lights to LED lites, which I should have done sooner,what a difference, When I first figured what power useage I have, it came out to about 140-150w per day, IFRR, not including the furnance useage, which I can't figure out yet.

The furnace the biggest user or power hog, which MUST BE USED to keep the tanks from freezing and provide inside heating, if the better half gets COLD, you don't want to be around, this is a 4 season RV, with heat being supplied to the tanks.

I have built a weather,wind and water proof nylon skirting around the whole RV, when using the Gen set, the furnance does not run as often nor long,
this skirting will be continued to be used, untill the temps rise above 50-60* constant.

Figuring the AVERAGE solar panels collection available in my area, where we spend most of our time, is about 4.0hrs per day during these winter months,
which include Elko, Ely, Winnamucca and Lovelock, NV.
I DON"T know about what effect the Clear Cold days will have on the solar panels for obtaining power etc.
Don't know how to figure it out etc.

Section #3 (new updated and corrected info)

I have bought the following equipment, so far:

4-220w CS6P-220M Canadian 220P panels with the following spec's:
STC Power Rating 220W
PTC Power Rating 198.5W 1
STC Power per unit of area 12.7W/ft2 (136.8W/m2)
Peak Efficiency 13.68%
Power Tolerances 0%/+2%
Number of Cells 60
Nominal Voltage not applicable
Imp 7.52A
Vmp 29.3V
Isc 8.09A
Voc 36.6V
NOCT 45°C
Temp. Coefficient of Power -0.45%/K
Temp. Coefficient of Voltage -0.128V/K
Series Fuse Rating 15A
Maximum System Voltage 600V

Monocrystalline Silicon
Output Terminal Type Multicontact Connector Type 4
Frame Color Clear
Length 64.5in (1,638mm)
Width 38.7in (982mm)
Depth 1.6in (40mm)
Weight 44.1lb (20kg)
Installation Method Rack-Mounted
CSI Listed Yes

Section #4
These solar panels will have an alum "L" frame 1/8" thick x 1-1/2" wide around each and every panel, so they can be securely mounted, and tilted when needed. The attaching "L" legs will be 4" tall and 1/8" thick, w/4 screws per leg into the roof.
All panels will be detachable for cleaning, maintance and tilting etc.

Section #5
TriStar MPPT TS-MPPT-60, w/temp sensor, with TS-RM-2 meter for inside RV monitoring etc,
Maximum Battery Current 60 amps
Nominal Maximum Solar Input
12 volt 800 Watts
24 volt 1600 Watts
48 volt 3200 Watts
Nominal System Voltage 12, 24, 36 or 48 volts DC
Maximum Solar Open Circuit Voltage 150 volts DC

Section #6
Batteries:
Not bought yet, depends on info recieved here,
there will be a minimum of 4, haven't decided on 6 or 12v, yet.

This wire size will be 4/0 Welding cable from batteries to CC etc.

From the battery install area, to the MS CC will be a max of 10' or less,
When the 4 panels are mounted on the roof and solar wiring brought down to the elect bay,
where ALL the OEM/solar equip goes.

The solar panel wires will be 2/series and 2 paraell,
about a 10-15' run for EACH PANEL WIRE, (all solar panel wires will be the same length, for balancing),
then 2 main wires down to the CC, about 10' Max run, again these wires will be the Same length).

Sorry for the long winded post, but I figured this info is valuable for the correct info recieved??

What do I have to correct or fix at this time??

If possible, please ref to each section as I posted them, to make things easier for ME to understand,
as I have a hard time wrapping my head around this solar stuff.

Thank you,
Don

Photowhit · November 2014

Re: Continuing Solar build for RV.

Pretty good info, we need to nail down your loads, so we need to figure out the furnace load. 2 ways to do this, a kill-a-watt meter if you want to rig up a plug and outlet for the furnace, or a clamp meter. I suspect it's just the fan running, so a clamp meter might be a cheap POS AC type to get some idea of the load, might check the meter against a know load to be sure it's close.

Cariboocoot · November 2014

Re: Continuing Solar build for RV.

It looks like you're down to this: you have four 230 Watt panels; how much battery can they support and will that be enough?

So a 920 Watt array on a 12 Volt system is about 59 Amps, maxing out that 60 Amp controller. When the weather goes cold the panel Voltage will go higher and even more power will be available, but the TriStar isn't going to let you make use of it.

With 60 Amps as the limit and using the 10% rule-of-thumb for battery sizing you get 600 Amp hour @ 12 Volts. You might go a bit higher, probably the most you could manage would be four Crown 305 Amp hour 6 Volts configured for 610 Amp hours @ 12 Volts.

Someone is bound to suggest LiFePo here, but the cold temps may be an issue (charging disconnect) as well as the cost.

What can you get from 610 Amp hours @ 12 Volts? About 3.5 kW hours at best. Is that enough? Good question. We don't have any number on the furnace demand and even if we did that would change with the weather! The end-to-end AC number on that 960 Watts would be about 2kW hours in 4 hours of good sun.

We also don't know if you can fit those batteries in. Here's a link to them: http://www.solar-electric.com/batteries-meters-accessories/batteries/crdecyinba1/stdecyba/cr305am6vode.html

This brings us to:
1). Can more panels be fitted somehow? Possibly as 'movable' units deployed only when parked?
2). Is there room for greater battery capacity or even the four 6 Volt units?
3). What happens when you run out of power? Running the gen at night isn't desirable, but a quick bulk in the morning may be?

Mountain Don · November 2014

Re: Continuing Solar build for RV.

Note, the furnace in an RV runs on 12 volts DC so the Kill A Watt won't help. A clamp meter like this Sears one would permit instantaneous readings and then you do the math. I have used a Watts Up meter for measuring DC. There are also other similar less costly brands out there. Nice thing about it is it can give you cumulative watts; watt-hours. Bad thing is it needs to be inserted into both the pos and neg wires.

westbranch · November 2014

Re: Continuing Solar build for RV.

You have some conundrums to solve,
1 what is the max size batteries you can use in the available space?
2 will you expand the array? Can you? Is there potential space on the roof or ?? for more panels?
3 You need to find out the draw of that furnace as it sounds like they are near finished if they will not last the night.
4 have you checked all cells for electrolyte levels and done an EQ on them? You might be able to recover them a bit, another season.
5 you will want a CC that will be able to use all 4 panels , possibly over PV but you have them, a Midnite classic can be Amperage limited to protect the batteries...

hth

Nvreloader · November 2014

Re: Continuing Solar build for RV.

Guys Thanks for the questions, which I will attempt to answer, starting with the way they were posted,

First off, I made an error and gave the WRONG info on the panels, (this info has been Now corrected to the correct info of my panels etc),
the CORRECT panels are these,

4-220w CS6P-220M Canadian 220P panels with the following spec's:
STC Power Rating 220W
PTC Power Rating 198.5W 1
STC Power per unit of area 12.7W/ft2 (136.8W/m2)
Peak Efficiency 13.68%
Power Tolerances 0%/+2%
Number of Cells 60
Nominal Voltage not applicable
Imp 7.52A
Vmp 29.3V
Isc 8.09A
Voc 36.6V
NOCT 45°C
Temp. Coefficient of Power -0.45%/K
Temp. Coefficient of Voltage -0.128V/K
Series Fuse Rating 15A
Maximum System Voltage 600V

Photowit
I bought a Killawatt meter, but could NOT figure out How to attach it to/in my RV, as there are NO electrical plug on the furnance wiring that fit this device in MY RV, so I can find to figure out the furnance useage etc.

IIRR,
when I started this project, I believe that the total useage of power for our use was right around 140 amps/watts?? (not sure which term to use),
per total 24 hr period, which included the running of the furnace hog, during the night etc.

This was BEFORE changing out ALL the internal lighting to LED type lighting etc.
The furnace comes on, runs for about 5-7 minutes, then recycles about every 20-30 minutes.
then shuts off, untill another cycle.

The 2 batteries in use NOW are HD Marine Trolling batteries, which are mounted on the tongue.

Cariboocoot
I can add 1 more 220w panel to the roof, then I am outa space to safely get up there.

I can add up to a maximum of 8 batteries to the new battery area I am building,
UNDERNEATH and BETWEEN the frame rails, this battery rack will be insulated and heat provided via the funance ducting,
which will adpated, as best as possible.
When servicing/checking these battery's, the battery rack can/will be raised and lowered via a small ATV winch,
made for that useage.

I don't know which type of battery to use, meaning 6 or 12 volt???

IIRR, I thought that the batteries could be conneted in a way to make 24v so the MS 60 MPPT CC to use??

I want to keep the weight to a minimum, but still have a reliable winter use system.

Mountain Don
I found out about the Killawatt meter!!!!!!!!
Will have to buy a clamp on style, I guess.
My rat hole funds for this project is going down the tubes, etc.

West Branch
Question #1, about the type/size of batteries was answered in Cariboo section,
I haven't decided on what or which would be the best for my appication??, at this time,
depends on the answers I recieve here.

Question #2, was also answered there, I can add 1 more 220w panel only.
Question #3, At this time, I am not sure,
but according to the OEM Idot lite meter installed, it states that the battery's NEED to be charged etc.

Question #4, I can't check these batteries, they are OEM sealed, and NO way that I know of.
Question #5, from the info I have been given, I thought that the MS 60 MPPT was going to be OK in my application??

Per MS caluator for panel power/useage, it shows I have the correct way to install them
2 in series and then 2 in parallel??

I can't find the site for this caluator, as I am using my laptop plastic box instead of the OLD desk top where all my info is stored.

I hope I have answered all the questions/replies with the info I know now.

Tia,
Don

Cariboocoot · November 2014

Re: Continuing Solar build for RV.

Don;

The battery bank (or system) Voltage depends on what is needed for the loads. If the loads require 12 Volts, that's it; you can't have a battery bank at 24 Volts (at least not without a lot of trouble and complexity). We really do need to know if the loads are all 12 VDC or all 120 VAC or a mixture of the two.

If you can have five 220 Watt panels that's 1100 Watts and would produce about 70 Amps on 12 Volts. Obviously too much for a 60 Amp controller. Going up to an Outback FM80 or MidNite Classic 150.

At that level you'd have enough charge capacity for 700 Amp hours; two parallel strings of two 350 Amp 6 Volt batteries in series. Like these: http://www.solar-electric.com/batteries-meters-accessories/batteries/crdecyinba1/repose/6voltbatteries/repoba6vo350.html

Just about anything would be an improvement over those Marine/RV batteries. They are probably about 90 Amp hours each, so any change is bound to go up.

That would be up to about 4kW hours capacity (50% DOD). At 25% DOD it would work well with the array for 2kW hours.

Instead of a Kill-A-Watt you might do better to get a battery monitor or at least a shunt-based Amp meter so you can see how much power is being drawn from the batteries depending on what loads are on.

Nvreloader · November 2014

Re: Continuing Solar build for RV.

Cariboocoot
Here is what I have or know at this time,

I have a Progressive 9260 charger/convertor/invertor? (OEM instaled), when it is plugged into 120V AC power, everything works in the RV,
when boondocking and NOT using AC power, but using the 4000w gen set and OR on straight 12v battery power,
everything works, BUT the batteries do NO last thru the night, when using the furnance.

So to guess?? at answering your question, USING the OEM setup, it is a combination of both 12v and 120v power.
And you are right, those 2-HD Marine trolling batteries won't work very long,
reason for this solar build/install.

I have the Morning star Trimetic battery gage/monitor with a shunt thing that came with it,
but don't know how to attach it to the exsisting OEM battery setup.

I perferr not to tear everything apart to install it, means removing the bottom 4 season plastic, running wires etc, (a Big PIB)
then having to do EVERYTHING all over again when installing the solar system etc,
unless it is required to find the info needed.

I hope this provides the required info needed??

Tia,
Don

Cariboocoot · November 2014

Re: Continuing Solar build for RV.

It appears that the PD 9260 is a standard RV issue converter/charger. These do not provide 120 VAC from the 12 VDC but just recharge the batteries and supply 12 VDC for loads when either shore power or the generator are hooked up. It is not an inverter.

So we may assume from that most everything, including the furnace, is 12 VDC.

If the batteries are still accessible out on the tongue it's fairly easy to put a shunt on them (negative side so that all current going in or out of the batteries pass through the shunt) and wire it up to take readings there.

I think the main problem is you have only about 90 Amp hours at best to work with, and that's about 1kW hour which isn't very much. If they are old and used it is likely much less than that.

Can you check the SG on them? That way you can see if they are charging fully (doubtful) and how much they are running down overnight.

Mountain Don · November 2014

Re: Continuing Solar build for RV.

The normal factory delivered setup in an RV is that everything runs on 12 VDC with the following exceptions:

The RV fridge which can be propane/120 VAC or propane/120 VAC/12 VDC with the electric being a heating element to replace the propane flame.

The air conditioner is another exception; 120 VAC only.

The TV and DVD, whatever, if factory equipped.

Some water heaters have a 120 VAC element as well as the standard propane burner.

~~~~~

Some of the upper class RV's come with an inverter, but that is rare, maybe non-existent, in the ones like the mentioned 27 footer.

They all have some sort of a converter to supply 12 VDC from the 120 VAC generator or shore power. The better RV's will be fitted with an automatic transfer switch between generator and shore power. The PD 9260 is one of the better converters used in RV's. It has multi stage charging.

Lights, furnace, water pump are all 12 VDC. And I can vouch for the fairly high consumption of most RV furnaces. Todays RV fridges are also somewhat power hungry even when operating on propane. This is due to the electronic controls they all now use. Constant draw just like a TV, etc when left plugged on but turned off.

Nvreloader · November 2014

Re: Continuing Solar build for RV.

Cariboo,
Everything is 12 volt.
Was NOT sure how or what the 9260 did or worked etc.
I can get to the 2 tongue batteries fairly easy, they were installed new last yr, just before Oct,
I'll read the install info and hook it up, for the info required.

Since the RV has been on 120V AC since March of 2014, I am sure that the batteries are fully charged,
since we are using 120V AC for the power for everything inside the TH, at this time.
(Have been living in it as the complete house remodel, inside and out side is just about completed).

Mountain Don,
The reefer is a 3 way, LPG, 120V and 12v,
Forget about the AC and TV's etc, don't use them,
send to much time outdoors doing what we Love to do etc.
Lights, furnance and water pump are 12v, as I understand it.
The water heater is elect and LPG for power.

Tia,
Don

BB. · November 2014

Re: Continuing Solar build for RV.

Ad Mountain Don said earlier, get a DC Current Clamp Multi Meter like this one from Sears (good enough for our needs and ~$60). You zero the meter and clamp it across one of the battery leads (you want the lead with all of the current flow, not just 1/2 of the current flow through the parallel battery connections). It will give you the current flow for each of your major appliances.

Of course, if your heater runs 50% of the time, then the average current is 50% of the measured value * hours per night = Amp*Hours per night.

-Bill

Nvreloader · November 2014

Re: Continuing Solar build for RV.

Thanks Guys

Will have to buy one when I go to Reno (110 mile drive 1 way) for my VA DR appt on monday.

Does it make a difference which battery lead is tested, meaning the - or + wire?

I have access to the 9260 convertor, there are/is a red and white #6? sized wires comning from the convertor,
and they disappear into into the frame work, going some where?

I greatley appreciate all the info/help so far.

Tia,
Don

Nvreloader · November 2014

Re: Continuing Solar build for RV.

Guys

Would a total of 4-200a+,= 800+amps total, 6v GC batteries be OK to start with, these would be the Costco brand, cost would be around $300,
they are easy to get and I would be afraid of using the higher $$$ batteries, untill I know and UNDERSTAND what I am doing.

Is there a formula for figuring out how many batteries or amps needed for X amount of panel wattage, to get reliable charging back into the batteries??

Corrected info.I found some of the original power useage calcuations for our useage,
If I remember right right, I thought that my TOTAL power usage, for a 24hr period,
INCLUDING the furnance draw for the night, was around 140-150 AH.
This was before all the elctrical bulbs were replace with LED type lights.

Does this amount of power useage sound correct??

I am attempting to find my info for everything when I first started this project, so I can properly answer your questions etc.

Tia,
Don

westbranch · November 2014

Re: Continuing Solar build for RV.

Simply take the Ah rating of the batts, say 225 which is avg for GC2's, , for that you need ~22.5 amps from the panels, using Imp rating off panel, for a 10% charge rate.

In actuality you will get ~ 73% of the watts out of the panel when you do the calculations for recharging for loads removed from the battery / day and use a 4 hr max hrs of good sunlight per day...

BB. · November 2014

Re: Continuing Solar build for RV.

For gc batteries, call it 6 volts at 200ah.

2 batteries in series, 12 volts at 200ha.

4 parallel strings, 12 volts at 800ah.

Or 16x golf cart batteries total.

I would look at my power usage again. That is a lot of lead.

-Bill

scrubjaysnest · November 2014

Re: Continuing Solar build for RV.

First of all the converter will never fully charge the batteries, the best it can do is 14.5 volts where most batteries want 14.8 or higher for absorb. The converters that go into RV's are meant to provide 12 volts to run the 12 volt systems. They are not intended to charge batteries. Second the heater is most likely a 30k btu unit so will draw about 6 or 7 amps; could be as high as 10 amps. Replacing the thermostat with a digital will help a lot on furnace cycle time and reduce you usage. The furnace is a very inefficient heating device. You may want to check out a LP wave type. It will need a filter because the liquid hydrocarbons in LP will foul the wave type heaters. Everything else has been pretty much covered by the others. To charge our batteries from an AC source I use a automotive smart charger. One will push 15 amps @ 15 volts during absorb, 7.5 amps for our two little batteries. I do have to watch it though as I've seen the voltage rise as high as 16 towards the end before it drops to float. I have a smaller one that regulates better but will only push 6.5 amps during absorb but is rock solid at 15.0 v. Panel wise I think the 4 should be enough.
Once you get the clamp on you can go through the RV and find all the parasitic currents. Radio even off is probably drawing an amp for example. Your refrig will also draw some for the electronics even on LP. The 12 volt water pump you can't do anything there except try to conserve water usage.

Nvreloader · November 2014

Re: Continuing Solar build for RV.

Westbranch

To make sure I am understanding what you have posted,

This is what I have come up with:
IMP rating from Panel = 7.52a
7.52a x 4 panels = 30.08a total
4hrs p/day of sun = 120.32a total p/day produced
75% = 91.24a actual amps total put back

With a 140a of power used p/day??

I am in the hole approx 29 amps every day?? OUCH!!!!!!

400a total battery amps available= 4/6v - 200a GC batteries
approx 140a used per day = 2.85 days of use before total dead battery's,
DoD 50% = 1.4 days of use

I got to change something in my useage and or add more batteries.

Please correct any errors.

Tia,
Don

westbranch wrote: »

Simply take the Ah rating of the batts, say 225 which is avg for GC2's, , for that you need ~22.5 amps from the panels, using Imp rating off panel, for a 10% charge rate.
In actuality you will get ~ 73% of the watts out of the panel when you do the calculations for recharging for loads removed from the battery / day and use a 4 hr max hrs of good sunlight per day...

Nvreloader · November 2014

Re: Continuing Solar build for RV.

BB
I see my error, I forgot these were 6v batteries,

I would have a total of 400a @ 12v from these 4/GC battery's.

Correct,

Tia,
Don

BB. wrote: »

For gc batteries, call it 6 volts at 200ah.

2 batteries in series, 12 volts at 200ha.

4 parallel strings, 12 volts at 800ah.

Or 16x golf cart batteries total.

I would look at my power usage again. That is a lot of lead.

-Bill

scrubjaysnest · November 2014

Re: Continuing Solar build for RV.

That is correct.
We meet a guy in AL earlier this year that solved the surface area for solar panels in a unique way. He had a roof mounted array and then on the front of the TT he had a second ~4 X 8 foot array that could be hinged up. This gave him about 1 kw of solar between the two arrays. The arrays were 48 volt to the CC with 3 Trojan batts on the tongue. He said this gave him enough to run the roof top A/C unit for 3 1/2 hours.

westbranch · November 2014

Re: Continuing Solar build for RV.

You have left off the time element here

Nvreloader wrote: »

This is what I have come up with:
IMP rating from Panel = 7.52a
7.52a x 4 panels = 30.08a total
you compare this number 30.08a to the batteries capacity

4hrs p/day of sun = 120.32aH total p/day produced
75% = 91.24aH actual amp-HRs total put back

With a 140aH of power used p/day??
this comparison is correct
I am in the hole approx 29 amps every day?? OUCH!!!!!!

400a total battery amps available= 4/6v - 200a GC batteries
approx 140a used per day = 2.85 days of use before total dead battery's,
DoD 50% = 1.4 days of use

Yes you are in a deficit situation, more storage will need more PV , your current setup is shy of the 10% target, about 3/4 of what is needed based on your heavy consumption.

Can you reduce your use?

Mustang65 · December 2014

Re: Continuing Solar build for RV.

scrubjaysnest wrote: »

First of all the converter will never fully charge the batteries, the best it can do is 14.5 volts where most batteries want 14.8 or higher for absorb. The converters that go into RV's are meant to provide 12 volts to run the 12 volt systems. They are not intended to charge batteries.

If you are interested, here is what the specs are for my RV's charge controller (which has been disconnected since going SOLAR):
Don
Attachment not found.

Nvreloader · December 2014

Re: Continuing Solar build for RV.

Ok Guys,

I have in my hot little hands, a Greenlee AC/DC clamp meter, Model CM 600,

I have access to the convertor, where the main wiring comes out for the RV and to the 2-12V tongue batteries wiring.

Which would be the better spot to test for the ah be used??

Which lead/wire would I be testing, ground - or hot + side of the wiring?

Any other information I should be aware of, while testing??

Tia,
Don

ps, I am reading and REREADING the manual as to it's correct operation, etc.

Cariboocoot · December 2014

Re: Continuing Solar build for RV.

You are wanting to test the Amp hours in/out of the battery. Therefor you want to connect with one of the battery wires. Whether you use the negative or positive side only makes a difference to the polarity of the flow, so as long as you keep that in mind either will work. If you goof it up then deficit charging will read as surfeit charging, or vice-versa. Follow the instructions with the meter carefully on this!

Also since it is an Ammeter it will not count up the Amp hours (usually). So you will have to keep track of the hours the meter is on. Therein lies another potential problem in that clamp-on DC meters tend to go out of calibration quickly; normally they are just used for at-the-moment current readings, not for running up Amp hours.

BB. · December 2014

Re: Continuing Solar build for RV.

Usually, the easiest method is to measure the current in the positive wire (many RV/automotive circuits use the metal of the vehicle for the return current--so it is difficult to measure with a clamp meter).

You can measure the current on the + input to the appliance... That will give you the load of that one device. Or you can find the main + (or -) wire from the battery bank where all the current flows, and measure there--That will give you the sum of the current of all the devices that are running at that moment. Usually, this is a good way to find "phantom loads" (loads that you did not even know were running/turned on).

You can also take multiple + wires and put them all in the meter clamp. It will measure the sum of all the currents.

Note, if you put a + and - wire together for the same appliance, the sum of the current will be zero amps. The clamp only measures the "net" current flow. Any opposite current flow will cancel/read negative.

Note that DC current clamp meters do "drift". They are using a Hall Effect Transistor--Which drifts with time and temperature. To get accurate readings, you will have to "rezero/recalibrate" the meter every few minutes or so...

-Bill

Nvreloader · December 2014

Re: Continuing Solar build for RV.

Thanks Guys

Questions?

Would it be adviseable to pull all the fuses out of the fuze block, in the RV, EXCEPT for the item I am checking the amps on, then go to the next item and so on??
That would limit or isolate just that one item etc.

I am NOT sure about these "Phantom Loads", what would those be??
To my knowledge, I don't or shouldn't have any??

If I take the reading on the furnace for 15 seconds and then X 4 = 1 minute total time, that would give the ah use for 1 minute,
then times the total run time of 5-6 minutes etc.

I have been timing the furnace "ON" run times and it averages between 5-6 minutes run time,
then stops and comes on just about 1 hr later for the next cycle of 5-6 minutes.

Our night time temps are running from 10* to 30* during the night.
I would think that the outside temps will have a bearing on just how long the furnace runs,
with the thermastat set at the lowest setting of 55*, this is where we sit it for the night.

Is this way of thinking/testing for ah used OK??

The main items would be the furnace, reefer, water heater and I would like to know on the coffee maker etc.

Anything else to remember or do?

Tia,
Don

westbranch · December 2014

Re: Continuing Solar build for RV.

I would measure with all loads on except furnace (de-fused) and get the total and then remove them one at a time, first turning the item off and reading the draw then remove the fuse and reread the total, if there is a change after removing the fuse you have a phantom load. In my camper the radio has a standby mode and a real OFF position, that is achieved with a separate button...

BB. · December 2014

Re: Continuing Solar build for RV.

Nvreloader wrote: »

Would it be advisable to pull all the fuses out of the fuze block, in the RV, EXCEPT for the item I am checking the amps on, then go to the next item and so on?? That would limit or isolate just that one item etc.

You can, or if you can access the wires--Just clamp one wire at a time.

I am NOT sure about these "Phantom Loads", what would those be??
To my knowledge, I don't or shouldn't have any??

They are loads you don't know about (something that draws power when the device is turned "off" is an example).

For simple power systems, you probably do not have any loads... However, you don't really know until you measure and find out.

If I take the reading on the furnace for 15 seconds and then X 4 = 1 minute total time, that would give the ah use for 1 minute,
then times the total run time of 5-6 minutes etc.

You measure the current--And get a rough average (i.e., 8-9 amps, call it 8.5 amps). Amp*Hours is the average current * the number of hours of operation.

For example, say you run the heater for 10 hours per day, it averages ~8.5 amps, and runs about 1/3rd of the time (i.e., 20 minutes per hour):

8.5 amps * 10 hours * 1/3 duty cycle = 28.3 Amp*Hours per day (Made up numbers).

I have been timing the furnace "ON" run times and it averages between 5-6 minutes run time,
then stops and comes on just about 1 hr later for the next cycle of 5-6 minutes.

Then that would be ~:

8.5 amps * 6 minutes * 1/60 minutes per hour = 0.85 AH per 1 hour period

In very cold weather, I have heard of these things running 30 minutes out of the hour (poor insulation, just the way things work in sub zero weiather?).

Our night time temps are running from 10* to 30* during the night.
I would think that the outside temps will have a bearing on just how long the furnace runs,
with the thermostat set at the lowest setting of 55*, this is where we sit it for the night.

Oh yea, if it gets colder (say near zero), it will probably run 2-4x longer.

Is this way of thinking/testing for ah used OK??

It is easier to get a Amp*Hour meter or Battery Monitor... They will "totalize" the Amp*Hours over the entire cycle.

The main items would be the furnace, reefer, water heater and I would like to know on the coffee maker etc.

Each load takes power... And many times, it is the smaller loads that run 12-24 hours per day that use the most Amp*Hours (running a microwave for 6 minutes takes a lot of power, but only for a 1/10th of an hour).

Anything else to remember or do?

With the DC clamp meter--Play with your CAR and see how it works (head lights on/off, engine on/off--Alternator running, etc.).

Note that the DC meter will have a +/- direction indication for current flow. If you "flip" the meter, the current sign will change. And make sure the meter is zeroed every minute or two (depending on how fast your meter's zero drifts).

-Bill

scrubjaysnest · December 2014

Re: Continuing Solar build for RV.

Mustang65 wrote: »

If you are interested, here is what the specs are for my RV's charge controller (which has been disconnected since going SOLAR):
Don
Attachment not found.

That is a very good graph to show exactly why RV converters will not fully charge the house battery(s). Most RV'ers choose Trojay 105's or equivalent. The Trojan site says 14.8 for absorb. My exides want 14.7 to 14.9. The interstates I use to have wanted 15.5 volts. The boost or bulk of 14.4 is fine but an absorb of 13.6 will never get you the last 20% or so. My Exides for example want C/10 up to C/10*5 or a maximum of 50 amps for bulk charge then raise the voltage to absorb of 14.7 to 14.9 and hold it there while the current tapers off. With the TS-45 I have it set for 14.8 absorb. I'm right at the ragged edge for C/10 with two 80 watt panels. The WFCO8955 converter that came with our trailer never went above 13.6 volts. This is what many RV'ers don't understand when they say I ran my ginny for xx hours and my batteries still didn't get charged.

scrubjaysnest · December 2014

Re: Continuing Solar build for RV.

What I did is started with everything turned off in the camper and then started pulling fuses at the distribution panel one at a time until I saw a current change. Then looked at the trailer wiring diagrams to see what was on that circuit. This is how I found the radio pulling 12 watts 24 hours per day with it turned off. You will also see how much the CO2/LP/low battery voltage detector draws. I also used a similar method to determine how much each device in the camper draws by turning on one DC item at a time.

Mountain Don · December 2014

Re: Continuing Solar build for RV.

I am NOT sure about these "Phantom Loads", what would those be??
To my knowledge, I don't or shouldn't have any??

Most likely your refrigerator is one of these. Modern RV refrigerators have electronic controls. When running on propane they still draw power, some of them as much as an amp.

Continuing Solar build for RV.

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