Getting it right the first time. (On a budget) Or close to it.

Joedog11

Hi to you all, I am starting to be a full time RV'er and would like to get setup on a good solar system for my use. I have been doing a lot of reading on this and I am getting more lost, mechanically inclined but not so electrically. So I'm turning to the experts. I will be using up to about 170-250 amp hours a day/night. Right now I have 2 AGM 6 volt 400 amp-h batteries each. Looking at a Xantrex sw3012 inverter/charger. So my questions are, What would be a good controller? or do I need to use the Xanbus controller with it? I have room for 4 to 5 solar panels on the roof of my trailer, So what kind? I would like to have my batteries at full charge by night and still be able to use T.V./satellite and heater if needed in the day.

Thank you for any help.
It is always better to seek the knowledge of others, Then to mess it up yourself.

BB.

Re: Getting it right the first time. (On a budget) Or close to it.

That is quite a bit of energy:

250 AH per day * 12 volts = 3,000 WH per day

That is pretty near to powering an off grid cabin with a refrigerator, washer, well pump, small TV, etc... (I use 3.3 kWH per day as a starting point).

If you assume that you are getting at least 4 hours of sun per day:

3,000 WH per day * 1/0.77 panel+controller derating * 1/0.80 battery losses * 1/4 hours of sun per day = 1,218 Watt array minimum

And if you plan on running these "flat" on the RV roof and through winter--4 hours may be on the high side for average.

So--I would suggest getting a Kill-a-Watt type meter and measuring your AC loads (and look at your DC loads too)... Figure out how much each of the major appliances/devices are using and see if you can get any improvements through conservation.

5x250 Watt panels on an RV roof is a lot... Can you fit that amount?

SolarWorld SW-255 Monocrystalline

-Bill

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

Thank you BB, I had someone that said I can figure that out for you do the math, So I guess I better check it out for myself. I will be running frig (I can use propane for it), heater on/off around 3-4 Hrs day/night, RV water pump, 32inch TV/HD sat. box, and the power for the dish about 8-10 hours, C-PAP machine for 8-10 hours, small microwave 2-5 min. (can use generator), Laptop, and lights.

I really don't want to do a upgrade with stuff if I don't need to. Guess I better start doing the math my self and see what I come up with.
Thank you again BB

westbranch

Re: Getting it right the first time. (On a budget) Or close to it.

Here is a search for CPAP C-PAP, seems to be a lot of interest for them...

http://forum.solar-electric.com/search.php?searchid=529313

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

Thanks Westbranch,
I did the math my self this time and I came up with 130 amp hrs. But I would like it to charge in 3 to 4 hrs.
Thanks for all or any help.

westbranch

Re: Getting it right the first time. (On a budget) Or close to it.

So to replace those Ahrs you will need a charger capable of 130Ah / 4hr = 32.5A, so you need a 40+- Amp charger capable of delivering a 3 stage charge, Bulk, Absorb and Float stages. At 12 V you will need a ~ 2000w generator to power a 40A charger.

Or were you referring to PV charge only? If so the same Amp output from the Solar array would , roughly be needed (40A) but getting 4 hrs of good sun in the winter is going to be a stretch...

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

Thanks Wesbranch,
I would like to be all solar if possible, What would get me close to what I need so I do not have to run my generator. I'm new at all of this solar stuff and trying to learn, If I use xantrex sw3012 inverter/charger with xanbus controller, and The TriStar MPPT" 600V charge controller, what size and how many solar panels will I need? Or is this over kill?

BB.

Re: Getting it right the first time. (On a budget) Or close to it.

I forgot to give you a link for a Kill-a-Watt meter (there are makes/models too these days).

Until you have measurements for each of your major appliances, you really cannot do detailed planning.

Energy usage is highly personal and what will work for one person probably won't for somebody else.

A 3kWatt inverter will probably run my entire three bedroom suburban home... For somebody else, they can get away with one or two 300-600 watt AC inverters for small cabin/RV...

-Bill

westbranch

Re: Getting it right the first time. (On a budget) Or close to it.

Well I know nothing about the Xantrex equipment other than the specs... so lets look at the loads as that will determine the battery banks and that determines the PV array...

the Microwave is a power hog no matter which way you look at it. So if you really want it, look at running the gen set when you want to nuke something, and put a bit of bulk charge into the batteries. I have 2 Honda Inverter generators, since they are nice and quiet. From the looks of it the 100W (really~800w) is too small, so a 2000W is in order. My 1000 would not start up my old Xantrex 40 True Charge(r) at full charge rate, so I used the 3000 to get a bulk charge going and then traded gen sets after 10-15 minutes.

So the SW 3012 is Way more than you need at 150A, the charger will easily charge your bank but needs ~3000W inverter to 'push' it. Your Call. Matter of fact you would need to throttle it back a lot... I believe these can be Charge Amps limited.

I do not know which batteries you have so the above is based on your stated 400Ah capacity. You don't want to go below 50% of the 400Ah, so the loads, 130W, will use about 65% of the available amperage, 200A. You might consider lowering that % to 50% or less per day, we generally target 20 to 25% per day based on having 3 days autonomy between good Sun days... and good (full) charging.

hth

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

Ok, Thank you all for the inputs, Now I will find a solar place that does RV's and have them do it. I will be going south for the winter after Christmas not sure how far yet. Guess I will plan this trip around a solar setup.

Again, Thank you all for the help.

vtmaps

Re: Getting it right the first time. (On a budget) Or close to it.

Joedog11 wrote: »

Ok, Thank you all for the inputs, Now I will find a solar place that does RV's and have them do it.

There have been some horror stories about "solar places that do RVs". Ask your solar place to give you a quote with a list of the equipment they intend to install, and then run it by us here on the forum.

--vtMaps

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

Sure will, Thanks vtmaps, My wife said I always over kill stuff. So right now just looking at a 2000 Watt inverter 400 watt solar pnls, 40amp mppt charger controller with 3 stage charging.

Blackcherry04

Re: Getting it right the first time. (On a budget) Or close to it.

Joedog11 wrote: »

Sure will, Thanks vtmaps, My wife said I always over kill stuff. So right now just looking at a 2000 Watt inverter 400 watt solar pnls, 40amp mppt charger controller with 3 stage charging.

I don't know about your generator, since you didn't say. I use a lot of SW 3012's, they are a good all around Inverter / Charger. As you already mentioned the 3000w is a little big for you ( Battery Bank Size ), the SW 2012 would be a better choice and save a little $$. The only quirk in them is to use " Generator Support " you have to have the AGS module, it costs $175 or so. The funny thing is it doesn't have to be wired up, just plugged into the Zanbus.

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

Ok Blackcherry04, If I use the sw2012 with the AGS plugged in to the xanbus, and a Truecharge2 Which one would do best the 40 or 60 amp. and what size of panels and would it all work though the xanbus controller or will I need to buy The truecharge2controller also? I am looking to keep my batteries up close to full to cut charger time down.

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

If I use 1 or 2 of the Grape Solar 250 Watt Polycrystalline PV Solar Panels with a xantrex sw2012 with the AGS plugged in to the xanbus, and a Truecharge2 Which one would do best the 40 or 60 amp? Would it all work though the xanbus controller or will I need to buy The truecharge2controller also since it is a 24 volt panel with a 12 volt system? I am looking to keep my batteries up close to full to cut charger time down.

Cariboocoot

Re: Getting it right the first time. (On a budget) Or close to it.

Joedog11 wrote: »

If I use 1 or 2 of the Grape Solar 250 Watt Polycrystalline PV Solar Panels with a xantrex sw2012 with the AGS plugged in to the xanbus, and a Truecharge2 Which one would do best the 40 or 60 amp? Would it all work though the xanbus controller or will I need to buy The truecharge2controller also since it is a 24 volt panel with a 12 volt system? I am looking to keep my batteries up close to full to cut charger time down.

You've got some terminology mix-ups there.

The Xantrex Truecharge is a battery charger, not a solar charge controller. It converts 120 VAC into charging Voltage & current for batteries.
The SW2012 is an inverter-charger; it has a built-in battery charger which will do the job the Truecharge does. Neither will take input from solar panels.

The 250 Watt Grape panels have a Vmp around 30 as I recall, and as such can not be used with any system without an MPPT type charge controller unless you can stand a huge loss in available power. Two of them would provide about 32 Amps charging current @ 12 Volts if on an MPPT controller.

jcheil

Re: Getting it right the first time. (On a budget) Or close to it.

I don't think anyone mentioned it but if that fridge is a dual (AC/Propane) fridge, you will likely not be happy with how much AC power it will take to run it. That in itself might end up being more than 1/2 of your daily consumption already.

Usually those types of fridges use a electric heating element to replace the "flame" of the propane to produce the heat. It will use WAY more energy than just replacing it with a modern energy star (even full-sized) fridge that has a compressor.

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

Ok all, Thank you guys for all your inputs. I called and ordered a system, and it should be here in a few days.
Thank you to Northern Arizona Wind & Sun.

I do have one more question.
The inverter/Charger Xantrex sw2012 says to use 4/0 cable for 10', Can I use 1/0 cable for 8'? (I would have about 0.08 Volt drop and 0.05 % volt drop. this would be the difference between the two). I have 1/0 cable and I would have to buy the 4/0.

Blackcherry04

Re: Getting it right the first time. (On a budget) Or close to it.

Joedog11 wrote: »

Ok all, Thank you guys for all your inputs. I called and ordered a system, and it should be here in a few days.
Thank you to Northern Arizona Wind & Sun.

I do have one more question.
The inverter/Charger Xantrex sw2012 says to use 4/0 cable for 10', Can I use 1/0 cable for 8'? (I would have about 0.08 Volt drop and 0.05 % volt drop. this would be the difference between the two). I have 1/0 cable and I would have to buy the 4/0.

For 12 V get all you can, forget the drop calculations, They don't always work out the way they seem on paper, buy the 4/0.

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

OK, I sure will then. Thanks and that's it for now. Good night to all.

westbranch

Re: Getting it right the first time. (On a budget) Or close to it.

So you will want to use the largest wire to the CC as well, in and out of the CC, etc. These are the places where the runs are quite short.

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

Sounds good, Next question, Do I have to shut down the solar charge when I plug into shore power?

Blackcherry04

Re: Getting it right the first time. (On a budget) Or close to it.

Nope, you shouldn't have to. Once you plug in the Inverter will transfer and you'll be on shore power with your loads on Pass Through and your charger will start, unless you take it off " force charge ". Your CC could have some issues if it's fighting with the inverter Charger. You have to determine the SOC of the batteries , the weather and the priority of charging daily . Once you get Bulk charging done then you can shut the Inverter charger down and let the sun finish the charge cycle off. So you tweak output voltages so they get along. It's a energy management game, it'll take you a while until you see how it works.

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

Awsome, Now, One more question. Instead of 4/0 cable can I use 350 and run the inverter/charger a little farther away then 10 feet?

Blackcherry04

Re: Getting it right the first time. (On a budget) Or close to it.

Joedog11 wrote: »

Awsome, Now, One more question. Instead of 4/0 cable can I use 350 and run the inverter/charger a little farther away then 10 feet?

Sure you can, you may still have a little more left in the 4/0 depending on how much your going to run on it. Things like Microwaves and Air Conditioners have a big power draw, thats what you have to be mindful of. If you don't have those loads then you can stretch is some. Be aware that MCM 350-500 is harder to find lugs for.

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

Well I can get the wire dirt cheep, off a scrap job, So I will have to see if I can get connectors or make some. Thanks

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

Ok, I have received my solar set up from Wind and Sun. Panels mounted (2 x 250w in parallel), all wires are ran to breaker box, Tristar 45 and batteries. The only thing that I need to wire in is the 15 amp and 50 amp breakers, Can someone tell me so I don't mess this up. The 15 amp goes between the panels and the controller and the 50 amp goes to the + from the controller to the batteries. Is that correct.

vtmaps

Re: Getting it right the first time. (On a budget) Or close to it.

Joedog11 wrote: »

The 15 amp goes between the panels and the controller and the 50 amp goes to the + from the controller to the batteries. Is that correct?

Yes. Are either of the circuit breakers polarized? If so, on the 50 amp breaker the "line" or (+) side of the breaker goes to the battery positive and the "load" or (-) side of the breaker goes to the positive output of the controller.

The 15 amp breaker, if polarized, should have its "line" or (+) side connected to the positive input of the controller and its "load" or (-) side connected to the PV positive.

--vtMaps

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

Thank you vtmaps, Yes they both are. So the info on that was great.

Joedog11

Re: Getting it right the first time. (On a budget) Or close to it.

One more question just to make sure I'm getting this right. What would be the best way to connect my panels, 2-250 watt pnls, tristar-45 CC, 2-6v EP 370s batt. Xantrex sw2012 inverter/charger. Parallel or Series?

BB.

Re: Getting it right the first time. (On a budget) Or close to it.

What is the Vmp of the solar panels?

And, I hope, that is a MorningStar TS MPPT type solar charge controller (and not the PWM controller--which don't work well with "most" >150 Watt solar panels that are designed for GT systems).

-Bill