OK considering a solar setup

[Seraphim]

Went to check my battery on the TC, and found an Interstate lead battery, rated about 73 amps (Interstated is not forthcoming with much info online, that I can find).<br /><br />Figured we use about 25 amp/hours a day, and was going to double up the batteries (about $105)&nbsp;to extend my time without shorepower. Thebattery setup is a little shabby, though. There is an extra vented battery box for a second battery, but the existing one doesnt seal properly: the grooves to let the cables out of the box are blocked by the installation, so theyre just laying between the box and the lid, preventing a seal. In otherwords, worthless.<br /><br />Came across this set-up from Home Depot:<br /><br /><a href="http://www.homedepot.com/webapp/wcs...EC-_-NavPLPHorizontal1-2-_-NA-_-203505912-_-N">http://www.homedepot.com/webapp/wcs...EC-_-NavPLPHorizontal1-2-_-NA-_-203505912-_-N</a><br /><br />Add about $450 for a 200ah AGM battery (8A4D from MK/Delta), and it should permit pretty much&nbsp;cover our&nbsp;12v power needs without much recharging from other sources, depending on our usage and the weather.<br /><br />The above kit has a 30 amp controller and a 450 watt inverter, plus cabling.<br /><br />Thought from the experts - is there something here I'm not seeing or considering?<br /><br />Thanks<br /><br />Note: also found out, apparantly, there's no isolator beteen the house and truck batteries. I disconnected the house battery, and the slide still funcioned, until I disconnected the cable from the camper to the truck. The battery meter must therefore meter the truck batteries, and not just indicate the house battery level.&nbsp; Have to be careful with that.<br /><br />

 

[IGBT]

I guess it isn't bad.&nbsp; 200 watts of mono solar is about $300 to $350, so you are paying around $300 more for the charger, inverter and cable.<br /><br />Can you return it to any home depot if you have problems?&nbsp; If so, that would be a big plus.

 

[Seraphim]

I also noticed they have a 250 watt panel for about 399, and a controller for about a hundred. Really don't need the inverter, and could buy the cable separately.

They indicate a return policy, and I would assume you'd return it to a physical store. I use home depot a lot, and would be more comfortable picking it up at the store than having it mailed to the house from another merchant.

 

[IGBT]

Are you think of using this when you go to Alaska?&nbsp; The insolation there is not super great compared with somewhere like Arizona.<br /><br />We were thinking of trying wind power in Alaska.&nbsp; Whenever we watch a show based there, it always seems to be blowing 20mph or more.&nbsp; 500 watt wind generator + 200 watts of solar would be a sweet setup!

 

[SoulRaven]

Hmmm to me these packages are all over priced with sub-par parts... The panels are of quality but are over priced, there are two of them and they are low voltage meaning heavier wiring coming into your vehicle... The controller is not MPPT, thus it is out of date and not close to the efficiency of an MPPT controller... The cabling has to be of marine grade to withstand the sun, heat, cold, wet environments it will be exposed to, the wiring HAS to be marine grade...<br /><br />Here is my comparable system at 185W... One 185W @ 36V Mono-Crystaline panel for $235.00... BZ250W MPPT controller that accepts up to 48V in and converts to a 12V DC out as the Amps increase into the battery at about 16 Amp/hour for $150.00... 400/800W inverter (Cobra) at about $40.00 on Amazon... So with mounting, wires/connecters, and self installation I am out about $500.00 with a great quality set-up... I also us a big 12V 8D deep cell at about $120.00 in a battery box between the seat bolted to the floor...<br /><br />So I guess the moral of the story is you can shop around, find deals and save money or you can buy a kit and save time while sacrificing money and quality...

 

[IGBT]

<p>MPPT controller is the way to go.&nbsp; Not having one is like having a manual transmission car with all the gears stripped but the 3rd.&nbsp; It will suck starting off the line, and it will suck at highway speeds.&nbsp; MPPT gives you a full range of gears for your solar panel, to make it operate at the best efficiency possible for a wide range of sun conditions and loads.</p>

 

[Seraphim]

Thanks Steve. Your comments on the individual parts were what I was looking for. I figured there was a catch, but I was too ignorant of the topic to figure it out.

IGBT

Yes, I did want to have it installed prior to the Alaska trip. I appreciate the advice on the controller, and I look forward. To reading about your experiments with wind power lol.

 

[Seraphim]

Steve

Using the mppt controller, would a 36v 195 panel delivering 5.41 ah at 36 v deliver 16.25 ah to the 12v battery?

 

[yesican]

Boy...I was doing great following this post until Seraphim started talking French...I'm lost again<img src="/images/boards/smilies/confused.gif" alt="" align="absmiddle" border="0" />.&nbsp; Someday, if I keep reading French, I'll learn to speak it!<br />Rae

 

[SoulRaven]

Yes 16.25 Amp/Hr would be the max at optimal conditions where a battery is low... The unique thing about the MPPT controller is that it eases off to a trickle charge as the battery gets full keeping it "Floating"<br /><br />You can see where you can save money in the wiring from the solar panel to the controller due to the higher voltage thus the lower amp's... The controller converts the 36V to 12V and thus increases the amps... But being inside you dont need "Marine Grade" wire so the larger/shorter wire is actually cheaper saving you money... Don't forget the in line fuse before the battery on the + side...<br /><br />

Steve Using the mppt controller, would a 36v 195 panel delivering 5.41 ah at 36 v deliver 16.25 ah to the 12v battery?

 

[IGBT]

Using the mppt controller, would a 36v 195 panel delivering 5.41 ah at 36 v deliver 16.25 ah to the 12v battery?

<br /><br />The MPPT controller is going to be at most 95% efficient (probably closer to 85% to 90%).&nbsp;&nbsp; At 90% you would probably see something like 13.5 amps at 13 volts during optimal sun measured at the output of the mppt controller while charging the battery.&nbsp; Note that you can have some pretty big I^2R losses in the cable from the charger to the battery.&nbsp; If your cable has a resistance of even 100 milliohms over the entire length, you will see a loss in the copper due to electron heating of 18 watts.&nbsp; This is why you want to use beefy cable and short runs where possible.

 

[Seraphim]

Thanks you two. Opened up a new dimension in my understanding, which wasn't all that deep to begin with lol.

Now if I can only find those great prices Steve was quoting. Just a bit of patience and checking around on my part.

From what I've found with a preliminary search, a 36v 190 mono runs about$300, the controller Steve mentioned, which is nice, about $350' and I'm looking at about $450 in AGM battery storage. The battery, on a normal day, should only discharge about 15% and recharge with two hours of direct sunlight. Ideally, during the day, it should remain topped off. Our main usage is recharging devices, and if done during the day shouldn't draw the battery down

If my understanding is accurate.

And I was ignoring efficiency and energy loss since I'll be producing about twice what I need, on a good day. But I'll take them into account in regards to cable gauge and distance.

 

[Seraphim]

And I'm assuming a 30A inline fuse would be sufficient?

 

[Seraphim]

Interesting info


http://www.amsolar.com/home/amr/page_167_9

 

[Seraphim]

More questions:

Looking at the camper today, it seems the shortest (14' from panel to battery) is to run the cable from the solar panel down the outside of the camper (in a PVC conduit) and have it enter the unit right at the vents to the battery box, on the lower front wall of the truck camper.

1 is it OK to mount a charge controller on the outside of the TC, beneath the over cab area where it would protected directly from rainwater?

2. Would I just connect the leads from the controller directlly to the house battery's terminals to charge it?

3. If I did #2 (no puns please lol) - and assuming there is no isolator between the house systems and the truck batteries - would the solar panels charge the truck batteries as well? Would that be the same as running the house and truck batteries in parallel?

Thanks on advance.

 

[Seraphim]

photo.JPG by jglennhart, on Flickr

The conduit would come down from the top to a controller mounted beneath the overhand. The vents that lead to the battery storage can be seen (barely) just above the front bed wall of the truck.

 

[IGBT]

More questions: Looking at the camper today, it seems the shortest (14' from panel to battery) is to run the cable from the solar panel down the outside of the camper (in a PVC conduit) and have it enter the unit right at the vents to the battery box, on the lower front wall of the truck camper. 1 is it OK to mount a charge controller on the outside of the TC, beneath the over cab area where it would protected directly from rainwater? 2. Would I just connect the leads from the controller directlly to the house battery's terminals to charge it? 3. If I did #2 (no puns please lol) - and assuming there is no isolator between the house systems and the truck batteries - would the solar panels charge the truck batteries as well? Would that be the same as running the house and truck batteries in parallel? Thanks on advance.

<br /><br />For #1, I would NOT mount the charge controller under the overhang on the outside of your camper shell.&nbsp; Think of all that road grime and slush up in Alaska that will splash up there!&nbsp; It will be one large lump of rusted components in about 6 months, if it even lasts that long.&nbsp; Also, you probably are going to pressure wash your camper/truck once every few months...you would have to remove the charge controller each time you did this.<br /><br />I would find a place inside to mount it.&nbsp; Depending on the efficiency of the unit (I will look up the model you are getting and read up on it) you probably won't need a lot of ventilation (ie, if it is 90% efficient and handling 150 watts, it only has to dissipate 15 watts of heat).

 

[IGBT]

The Morningstar Sunsaver MPPT looks pretty small, and is up to 97% efficient.<br /><br />there is a thread about them on wind-sun forum:<br /><br /><a href="http://www.wind-sun.com/ForumVB/showthread.php?7043-Charge-Controller-Q-s-MorningStar-Sunsaver-MPPT">http://www.wind-sun.com/ForumVB/showthread.php?7043-Charge-Controller-Q-s-MorningStar-Sunsaver-MPPT</a><br /><br />and they are about $220:<br /><br /><a href="http://www.ebay.com/itm/Morningstar...pt=LH_DefaultDomain_0&amp;hash=item3a66e5bcb4">http://www.ebay.com/itm/Morningstar...pt=LH_DefaultDomain_0&amp;hash=item3a66e5bcb4</a>

 

[Seraphim]

Thanks for the comeback.. Should be easy enough to mount just inside near the vents.

 

[akrvbob]

Here is a 315 watt Kyocera panel for $378<br />http://www.solar-electric.com/kykd315wamus.html<br /><br />here are lots of good deals from a company I highly recommend:<br />http://www.solar-electric.com/hiposopa.html<br /><br />Be aware of the size of the panels, make sure they will fit on the TC roof. Be aware high watt panels have to go freight so shipping will be higher, much higher. They will also use a MC4 connector. That's no problem, just buy an extension cable and cut the ends off it.<br /><br />I would NOT mount a controller outside the TC. They aren't fragile, but that would be abusive. By far the best deal on a high amp controller is the BZ 500 mppt controller by BZ products. Solar Mike at the Slabs is using one to operate his office. I have another friend with one and 410 watts and has been very happy with it.&nbsp; Bob