Hi allI know, Im sure this has been answered before somewhere here but what the heck. While I was just sitting being lazy today, I said why don't I go on top of the MH and measure some to see what kind of room I have up their. Well, between all the antenna's, air conditioners, vents and such, I came up with some figures. After looking at dimensions of some of the larger 24 volt panels, it started to look like I might be better off with the smaller 12 volt 100-140 watt types. Anyways, it appears I may have room for 4-6 panels probably configured in 2 or 3 two panel groups. Im getting to the question.....would it be wise to series wire each set of two panels and then parallel, giving me 2 or 3 24 volt arrays? Im just in the "thinking" process now but since I took the first step to measure, may as well ask away....:B We don't do a lot of dry camping/boondocking but I could do a lot more, I currently have (6) 6 volt batteries.

Hi,If using 17 volt panels it may be cheaper and better to wire them in parallel and use a pwm controller with a temperature probe to optimize charging voltage.If you wire them in series/parallel a more expensive MPPT controller must be used.When panels were more expensive mppt made good sense. Now they are dirt cheap the greater ability to wring watts out of the panels is not quite so important.

http://www.batterystuff.com/kb/tools/solar-calculator-tutorial.htmlhttp://forums.trailerlife.com/Index.cfm/fuseaction/thread/tid/25705772/srt/pa/pging/1/page/1.cfmhttp://www.jackdanmayer.com/rv_electrical_and_solar.htm#The Golden RulesI choose to use the quick reply, instead of inserting Links.Everything you really wanted to know is here.

You should consider the shipping costs asssociated with the larger panels as well as the logistics of getting them up top and mounted. Check out the dimensions/weights look at UPS web site them check out the alternatives many are very pricey Yes sure a series parallel arrangement of the panels can be used as well as a simple parallel arrangement or a total series. Too many variables to offer much more.

gatorcq wrote:http://www.batterystuff.com/kb/tools/solar-calculator-tutorial.htmlhttp://forums.trailerlife.com/Index.cfm/fuseaction/thread/tid/25705772/srt/pa/pging/1/page/1.cfmhttp://www.jackdanmayer.com/rv_electrical_and_solar.htm#The Golden RulesI choose to use the quick reply, instead of inserting Links.Everything you really wanted to know is here.http://www.batterystuff.com/kb/tools/solar-calculator-tutorial.htmlhttp://forums.trailerlife.com/Index.cfm/fuseaction/thread/tid/25705772/srt/pa/pging/1/page/1.cfmhttp://www.jackdanmayer.com/rv_electrical_and_solar.htm#The Golden Rules

We do alot of camping off the power grid and want to run just about the same items we run at an electric site but of course no air conditioning or high wattage microwave. Also there will be times we won't be running the high battery drain associated with the Propane heater blower motor.We are currently very successfully doing all of this with our upgrade to smart mode converter/charger, led lights, and more batteries.The concept for us is to run all of the 120VAC items we want to run from a 600WATTS PURE SINE WAVE Inverter and run all the 12VDC item we want to run direct connected to the battery main switch.With all of this planned out our battery bank drops to around 12.0VDC very morning around 8AM and then when allowed by the camp ground rules can run our 2KW Honda generator to re-charge our battery bank back up to its 90% charge state. Our battery drain is right at 20AMPS from 8PM to 11PM and the keep alive battery drain the parasitic drain is 1-2 AMPS all the time. As stated above we are very successful doing this but have to start each day off with fresh 90% state of charge batteries.I too am now looking into installing SOLAR PANELS... My OFF-ROAD POPUP trailer ROOF area can be fitted with two 120WATT SOLAR panels installed on each side of the fantastic fan location on the front part of the roof. I also have one other spot between the air conditioner install location and the rear part of the roof running across the roof for a 120WATT size solar panel. The 120WATT solar panels will only produce around 18VDC @ 5-6AMPS each (At high noon I presume) so these will connected in parallel and will use the solar controller tied to my battery bank.What I am finding out is this solar energy at the battery terminals when being used will only provide me smart mode charging of the 14.4VDC/13.6VDC/13,2VDC modes with a capacity of around 15-16AMPS. Based on battery science this will not be enough battery charge for my particular battery bank to get me back to a 90% charge state each day to sustain my current battery drain each day. I am sure all of this is really going to help me but it appears if we want to run all of the things we are currently using during the one day/one night camping run off the batteries we will have to still use the generator each day when allowed by the local campground to always start off my battery bank run with a 90% charge state.From past experience I have learned not following this 50% to 90% discharge state with my batteries they will not perform as expected and eventually will start doing damage to the batteries.I have not done any real time use of solar panels yet but I suspect if I get enough charge back into the batteries during the day but still have to run my generator to insure I get back to the 90% SOC then the generator will still need to run three hours to attain this. I am not sure my PD9260C will know that the batteries might already be at the 70% or 80% SOC and will just run thru its normal three hour smart mode charge routine. Actually I suspect my PD9260C converter/charger will not even go into smart mode charging in auto mode if the batteries are already up to 70%/80% charge state. I will have to force the PD9260C into its 14.4 charge mode. When i do this I think it run its full three hour smart mode run.The smaller SOLAR PANEL installs will definitely make a great trickle charge system during the ONE DAY of SUN but will have to used more long term to bring a 50% SOC battery bank back up to its 90% SOC state. i.e. you can't use any short cuts here to re-charge your battery - what you take out you have to put back...The bigger plan would be to have a bigger battery bank than you need and then when running solar during the day it will have a place to store all of the solar it gets. The larger battery bank will not get down to its 50% SOC in a one day/one night run off of the batteries... The other solution of course is not planing on using as many 120VAC and 12VDC appliances items as before... We was wanting to stay away from candles and flashlights as much as we could - we paid those dues already from our early tent camping years from the late 50s...My first impression on solar panels was thinking i if I installed 120WATT panels I would get a full 120WATTS of solar energy to use. The 120WATTS is based on the Dc VOLTAGE output of the panel and when you use the solar controller to get the smart mode charging voltages you need the available DC current out is reduced alot. Most 120WATTS panels have around 5-6AMPS usable DC current available. Just some of my early thoughts here on what I may expect to gain from adding solar panels... Every situation will be unique... The ones that jump up and down saying they last for multiple days on end by adding solar panels are not using the same amount of DC power I am currently using each day/night battery run. (Unless I am missing something here). In the short term my three 120WATT added SOlar Panels will not be much help - I will still have to run my 2KW generator each day when allowed for our lifestyle of camping off the power grid... This makes me think I might be better off by using the $150 per 120WATT panel for more batteries hehe... All of this plays together for sure... I may have a different story to tell once I have added the three 120WATT solar panels and get some real time using them off the power grid...Roy Ken

Solar again? | Good Sam Community

JiminDenver
Explorer II
Aug 23, 2013
BFL13 wrote:
pianotuna wrote:
Hi Jim,

How do you get 200 amp-hours from 230 watts of panels? It seems pretty high.

Don't forget my daily haul figures for one 130w panel
Flat- 56AH
Tilted pointing South- 70AH
"Tracking"- 90AH

So 200AH with 230w "tracking" in the conditions Jim describes seems reasonable to me. AND, he cheats! (He has MPPT :) )

BFL

I'm waiting to see what you say about that fake MPPT controller, for $12 I'll take the 12a or so that my 220w panel will put out "up there".
pianotuna
Nomad III
Aug 23, 2013
Hi Acamping,

They seem to have reasonable prices and excellent specials.
Acampingwewillg
Explorer II
Aug 23, 2013
That's a good point....I did notice there in Norco? So it would be not all that bad of a drive for me too and Yep, Id hate to drive all way down there to find out they were out of stock on what I wanted. Sounds like something Id do!
time2roll
Nomad
Aug 23, 2013
Acampingwewillgo wrote:
Thank you for the additional comments.....after reading through the vast amount of threads regarding Solar, it appears Solar Blvd is one of the more popular places to purchase?

I bought my equipment at SB because they have good prices, sell single panels, and they are local to me to save shipping. Although I have ordered stuff sent also.

If you plan to drop in be sure to call first as they told me not all inventory is not on site all the time. May take a day to have it in stock.
gatorcq
Explorer
Aug 23, 2013
Thank you for converting to Links.
Acampingwewillg
Explorer II
Aug 23, 2013
Thank you for the additional comments.....after reading through the vast amount of threads regarding Solar, it appears Solar Blvd is one of the more popular places to purchase?
time2roll
Nomad
Aug 23, 2013
Acampingwewillgo wrote:
Im getting to the question.....would it be wise to series wire each set of two panels and then parallel, giving me 2 or 3 24 volt arrays? Im just in the "thinking" process now but since I took the first step to measure, may as well ask away....:B

We don't do a lot of dry camping/boondocking but I could do a lot more, I currently have (6) 6 volt batteries.

If all panels are matched you could put all in series. The panels need to have bypass diodes and you will need an MPPT controller. Otherwise I prefer the simplicity of the series configuration.

May as well get lower cost 24v panels from the start.
2oldman
Explorer II
Aug 23, 2013
Acampingwewillgo wrote:
would it be wise to series wire each set of two panels and then parallel, giving me 2 or 3 24 volt arrays?.
Depends. As you go up in voltage your wiring can become smaller. More expensive controller though. If you're prewired from the roof that may not be a very big wire.

I run 6 panels in series.
BFL13
Explorer II
Aug 23, 2013
pianotuna wrote:
Hi Jim,

How do you get 200 amp-hours from 230 watts of panels? It seems pretty high.

Don't forget my daily haul figures for one 130w panel
Flat- 56AH
Tilted pointing South- 70AH
"Tracking"- 90AH

So 200AH with 230w "tracking" in the conditions Jim describes seems reasonable to me. AND, he cheats! (He has MPPT :) )
JiminDenver
Explorer II
Aug 23, 2013
Hi Don

Tracking I easily average 15a from just after sun up to dusk. Last trip the sun was fully up by 6am and set at 8:30 pm. That's up to 14 hours at 15a. (210a)

You have to remember the altitude I camp at. 9-10,000 ft really supercharges the panel to the point I can get up to 14a in PWM from a panel rated for 8.33a. Most of the day it can do closer to 16a if needed. ( enough to run a 12v auto drip coffee pot and not lower the batteries voltage)

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