Off Grid RV System

Chris

Hi guys,

I'm new to the site and to solar, over the past summer I have been putting together a small off grid system for my trailer (permanently parked with good southern exposer)

So first a little about my system,

2x100 watt panels (plan to add 2 more)
20 amp PWM controller (I'm thinking of going to a Tracer 30amp in the spring)
moto master Eliminater 3000 watt modified sign inverter


Right now I have a dedicated plug for the inverter but I pan an adding a transfer switch and hard wiring in to the panel soon here.


So.....here is my question, my batteries are pooched and I'm going to be purchasing some new ones in the spring.........with just running the 12 volt furnace and a few hours of TV on weekend stays, would I need more then 2x6volt 220 amp hour batteries?

Do I have enough panel now?

any thoughts on the Tracer controllers?

Thanx, Chris

westbranch

Re: Off Grid RV System

Welcome

Please post the specs to those panels.
What is the price of the Tracer, ( not recommended, it appears to be a knock of of a good US made one with fewer features).
What is the load of that furnace and the TV? You need a Kill a Watt meter for 120v load measurement.

cheers

Chris

Re: Off Grid RV System

Hi Westbranch,

I have to different panels,
1 X VMP 18.8v, IMP 5.32 http://islandlifewholesale.com/100w-Mono-Crystaline-Solar-Panel-PWM-100.htm
1X VMP 19.35, IMP 5.17amp http://www.papsolar.ca/pdf/100W19V%20Mono.pdf

As for the TV, I will be putting in a new one soon here......and the back says "topical 38 watt" and well the DVD player......I'll have to look the next time I'm out there.


The furnace......well, I have no idea...I'll have to see if I can find the manual

As for the Tracer......the best deal I've found is about $210 with the remote screen (plus tax)
http://www.solarenergydc.com/index.php/en/component/virtuemart/charge-controllers/2012-02-22-03-49-309-69-70-detail?Itemid=0


I just noticed that your in BC as well......I've been hunting high and low for a good place to buy batteries/panels and charge controllers.......where do you order your stuff from?

zoneblue

Re: Off Grid RV System

Chris wrote: »

Hi Westbranch,
I have to different panels,
1 X VMP 18.8v, IMP 5.32 http://islandlifewholesale.com/100w-Mono-Crystaline-Solar-Panel-PWM-100.htm
1X VMP 19.35, IMP 5.17amp http://www.papsolar.ca/pdf/100W19V Mono.pdf

200W gives you a bit to play with so long as you dont start trying to add to many loads. Definately wont run a fridge for instance.

The furnace......well, I have no idea...I'll have to see if I can find the manual

The sucess of failure of every PV system hinges on the owner understanding the nature of their loads. If you cant find the manual, and even if you can, measure the draw, and times that by the number of hours per day, worse case scenario. Do the same for lighting, tv etc. That gives you the all important Wh/day figure you need to base all the other decisions on.

As for the Tracer......the best deal I've found is about $210 with the remote screen (plus tax)
http://www.solarenergydc.com/index.php/en/component/virtuemart/charge-controllers/2012-02-22-03-49-309-69-70-detail?Itemid=0

Tracer are the better end of the chinese stuff. They arent bad as far as they go. Midnites new "Kid" controller wont be out for another few months but that will definately be THE small controller to get.

I just noticed that your in BC as well......I've been hunting high and low for a good place to buy batteries/panels and charge controllers.......where do you order your stuff from?

Right here. I live in NZ and have just made my second order to NAWS.

Chris

Re: Off Grid RV System

zoneblue wrote: »

Tracer are the better end of the chinese stuff. They arent bad as far as they go. Midnites new "Kid" controller wont be out for another few months but that will definately be THE small controller to get.



Right here. I live in NZ and have just made my second order to NAWS.

I just googled that "Kid" controller......that looks fantastic, any idea of what it will cost when released?

westbranch

Re: Off Grid RV System

they are not on the street yet, but looks like it will be in the $300+ price range plus shipping etc. Don't quote me on that as it is from another thread.

Chris

Re: Off Grid RV System

westbranch wrote: »

they are not on the street yet, but looks like it will be in the $300+ price range plus shipping etc. Don't quote me on that as it is from another thread.

Could you recommend a good battery supplier here in B.C. (I'm trying to keep the shipping down)

westbranch

Re: Off Grid RV System

check your local auto parts store, Costco, Walmart, etc. A friend got his GC2's at a Lordco outlet.

Chris

Re: Off Grid RV System

zoneblue wrote: »

200W gives you a bit to play with so long as you dont start trying to add to many loads. Definately wont run a fridge for instance.

So.....for next summer, if I wanted to run a small fridge (bar fridge) would I need to add alot more panel? say another 2 hundred?

It would only be on over the week ends......and the occasional week stay.

Rybren

Re: Off Grid RV System

Chris,

These guys are listed as being retailers for US Battery brand batteries. They seem to have stores across BC. There might be one near you.

Chris

Re: Off Grid RV System

Rybren wrote: »

Chris,

These guys are listed as being retailers for US Battery brand batteries. They seem to have stores across BC. There might be one near you.

Jerry? is that you? LOL

Sorry, which guys were that?

Rybren

Re: Off Grid RV System

Chris wrote: »

Jerry? is that you? LOL

Sorry, which guys were that?

Hey Chris, yeah it's me! What are the odds?

There's a link embedded in the word These

but if you prefer, here's the link...

http://www.cdnrg.com/

Chris

Re: Off Grid RV System

Doh!! LOL,

Sorry bout that, I must have been color blind the other day....I didn't even see the link.

Hummm.......looks like they have a store in Kelowna (about 2.5-3hrs away)

As I recall from your thread you ended up getting some of those US Batteries....I didn't realize there were so many of them, what model did you buy? Was this who you bought them threw?

Rybren

Re: Off Grid RV System

Hi,

I bought the 2200XC2 232AH 6V batteries. I picked mine up at a Ottawa-based battery store called Total Battery. IIRC, they were about $180 each including core charge.

Canadian Tire carries a 6V GC battery that I think is 220AH, but their price is ~$199 plus $15-$20 core charge.

Cariboocoot

Re: Off Grid RV System

Check your local auto parts and service centers too. I bought my East Penn PS2200 from the local KAL tire, no problem. The junkyard near here sells Crowns and can order in their deep cycle models. Often the shipping to a place like that is much less (because it is on the standard delivery truck) than from a 'discount' seller. Plus you help keep the local economy going.

Chris

Re: Off Grid RV System

I tell ya, I'm really kicking my self right now, last month my local Lordco had T-105re's on for $150 + tax........but I thought I could find a better price LOL. I'm still a few months off from buying batteries yet (wife says I have to pay for X-mas first)

On the other hand, my father in-law has a buddy that is supposed to be getting me some GIANT telecom 2 volts (200 pounds each!)..but after waiting for 6 months now with pooched batts I'm almost ready to bite the bullet and just buy 4 new 6 volts.

By any chance, do you guys have any idea how much power the 110 side of a RV 3 way fridge would consume?

Cariboocoot

Re: Off Grid RV System

Those telecom batteries may not be the best choice anyway, as they are probably "standby" power units meant to sit at float all the time and be used occasionally rather than discharged significantly every day. The two applications are really quite different.

Chris

Re: Off Grid RV System

So, are you saying they wouldn't work? or that they wouldn't last very long?
So if by some chance he does come threw, would it be worth running them for as long as they last if they were free? or would you just go straight for the Golf cart type batts?

Cariboocoot

Re: Off Grid RV System

"For free take, for buy waste time."

They would probably suffer a shortened life due to the frequency and depth of cycling. Do you really want to schlepp 200 lbs. batteries? How's the scrap metal price there? Most important: how critical is the application? If they fail suddenly, what will happen?

Your RV 'frige draw will depend on the particular unit. Quite often the electrical side is just a heating element to replace the propane flame. Not as efficient as a motor-compressor.

Chris

Re: Off Grid RV System

Come spring, I plan on adding 2 more 100 watt panels, now I already have one of these and just wanted to know what you guys think of them.....are they any good? or should I be looking at a different brand?

There pretty cheap, I can get them for $125 ea +tax and shipping

http://www.solarfennel.com/Products/Solar_panel/f8968f56e6f84c76/

I think I've made up my mind about the CC as well, I'm 99% sure I'm going to go with the "Kid" seems like they have a good reputation and well it's going to be flush mounted under my fridge and it should just fit

BB.

Re: Off Grid RV System

As always, check the handling + shopping costs to your front door.-Bill

BB.

Re: Off Grid RV System

Looks like I accidently closed this thread when posting from my phone.. 3"screen just does not show everything.Sorry,
-Bill

Chris

Re: Off Grid RV System

BB. wrote: »

As always, check the handling + shopping costs to your front door.-Bill

I have already bought one from a supplier here is BC so shipping wasn't bad.....I think tax & (over night) shipping all said and done was like $160 so it should be bout 290 ish for 2 more.

Chris

Re: Off Grid RV System

Cariboocoot wrote: »

The inverter draws from the batteries, so it's 0.4 Amps @ 12 Volts.

The full calculation would be:

AC Watt hours / inverter efficiency = DC Watt hours
Add inverter Watts * time on to get total DC Watt hours
Divide by nominal system Voltage to get approximate Amp hours used
This should be multiplied by 4 to get Amp hour capacity of the battery bank for 25% DOD

Ok so I've gone threw all my manuals for the trailer and none of them say what the 12volt furnace blower motor use's for power. With out having acsess to a DC clamp on amp meter how would I go about calculating that out?

Cariboocoot

Re: Off Grid RV System

Chris wrote: »

Ok so I've gone threw all my manuals for the trailer and none of them say what the 12volt furnace blower motor use's for power. With out having acsess to a DC clamp on amp meter how would I go about calculating that out?

No rating anywhere? No fuse dedicated to it?

Chris

Re: Off Grid RV System

Hmmmm....I'm sure there is a fuse for it, I'll have to have a look this weekend wile I'm out there to see what size it is. Would you be able to give an adjucated geuss to consumption base off the size of the fuse?

Don't suppose there would a sticker somewhere on the housing that would list power ratings do you?

BB.

Re: Off Grid RV System

Folks here before have said their furnance takes about 8 amps @ 12 volts for their systems.

A "good enough" DC current clamp meter from Sears (really an AC/DC current clamp+DMM) is less than $60 right now... Will be pretty handy down the road for debugging your DC power systems.

-Bill

Chris

Re: Off Grid RV System

So, just to see if I have this right,

My Batts are 220 AH......220X12=2640 watt hours? and if the furnace pulls 8 amps thats 96 watts per hour....so when It's cold out I only run the furnace at night say for 12 hours, if it kicks in for 10 mins once an hour. Then I'm pulling 192 watt hours out of the batts for just the furnace? is that right?

Cariboocoot

Re: Off Grid RV System

Chris wrote: »

So, just to see if I have this right,

My Batts are 220 AH......220X12=2640 watt hours? and if the furnace pulls 8 amps thats 96 watts per hour....so when It's cold out I only run the furnace at night say for 12 hours, if it kicks in for 10 mins once an hour. Then I'm pulling 192 watt hours out of the batts for just the furnace? is that right?

Not quite.
If you have two 220 Amp hour 6 Volt batteries in series you have 220 Amp hours @ 12 Volts which is 2640 Watt hours, but you can't use all of it. By the time it gets down to 50% SOC you want to stop, so that's 1320 Watt hours maximum available. This also varies with the rate of draw, but 8 Amps intermittent shouldn't be a big problem.

Otherwise yes, 96 Watts 10 mins per hour over 12 hours works out to 196 Watt hours and the batteries should be able to handle that without any trouble.

Chris

Re: Off Grid RV System

Cariboocoot wrote: »

Not quite.
If you have two 220 Amp hour 6 Volt batteries in series you have 220 Amp hours @ 12 Volts which is 2640 Watt hours, but you can't use all of it. By the time it gets down to 50% SOC you want to stop, so that's 1320 Watt hours maximum available. This also varies with the rate of draw, but 8 Amps intermittent shouldn't be a big problem.

Otherwise yes, 96 Watts 10 mins per hour over 12 hours works out to 196 Watt hours and the batteries should be able to handle that without any trouble.

Perfect, I think I'm starting to get my head wrapped around this stuff (I know took my long enough LOL)

As luck would have it, I got an amp clamp meter for my birthday yesterday can't wait to get out to the lake to start testing everything 8)

So.......I've been going around the house clamping this on to different devices, and it always reads zero.....I take that means that I have to separate the wires and only clamp one at a time?

this is the model I got
http://www.active123.com/MTP-3094-ACDC-Clamp-Meter-400AAc-4000-Counts-Prodview.html

ILFE

Re: Off Grid RV System

Chris wrote: »

Perfect, I think I'm starting to get my head wrapped around this stuff (I know took my long enough LOL)So.......I've been going around the house clamping this on to different devices, and it always reads zero.....I take that means that I have to separate the wires and only clamp one at a time?

Yep. Clamp it only around one leg of the circuit. It cannot read amperes if you clamp both legs of a circuit, whether AC or DC.