Help! Solar generator - Hi-Lo camper travel trailer forum

lewang3 · 11-28-2011, 12:17 PM

Dear members I wanna buy a solar generator with the following:
100w solar panels 2
24 v30a controller
24 v600w inverter
100 ah 2 gel VRLA batteries.
do the above characteristics fit my needs. I've a Tv,Laptop,8 Lamps, and Ice-box. I want a battery that can work at least 12 hours.If I buy two batteries, will the battery capacity increase twice?.
thanks in advance

RichR · 11-28-2011, 01:06 PM

I am only going to try the battery part of your inquiry. If you connect two 12volt, 100ah batteries in parallel you will get 12volts and 200ah, and if you connect them in series you will get 24volts and 100ah.

Your plan sounds a bit ambitious, but I am not a solar charging expert. Standby and someone will come forth with the needed info.

JMDoering · 11-29-2011, 08:39 PM

Haven't run the numbers, but I'll venture a guess that you would spend much less by buying a quality gas generator. Plus you would probably have a more reliable set up that will take up a lot less space and would not be as vulnerable to travel damage.

Just my opinion,
Jim

Richard · 12-03-2011, 07:43 PM

Quote:

Originally Posted by lewang3

Dear members I wanna buy a solar generator with the following:
100w solar panels 2
24 v30a controller
24 v600w inverter
100 ah 2 gel VRLA batteries.
do the above characteristics fit my needs. I've a Tv,Laptop,8 Lamps, and Ice-box. I want a battery that can work at least 12 hours.If I buy two batteries, will the battery capacity increase twice?.
thanks in advance

Not sure why you are looking at a 24 volt setup, but if you are needing 24 volt you will have to go with two batteries in series which will cause you to derate your capacity by about 10%. If you go with two 200 Ah batteries in series, you will be able to handle a load of about 4000 watts for about thirty minutes. If you cut your load in half (2000 watts) you will increase your time to about an hour and a half. To determine your load you will need to check the tag on each unit and multiply the name plate amps times the voltage to get the wattage. Most twelve volt small lamps run about thirty watts. Your inverter is going to be the biggest power hog. So your 24 volt system will provide you about 350 watts of power for about twelve hours, but you need to remember that you will need to decrease your load as the batteries begin to discharge. Electronics, inverters and motors are very susceptible to damage from low voltage.

davidc · 03-25-2012, 10:16 PM

You also need to sit back and figure out what runs continuous, once in awhile, and how often and why it all runs...

Inverters kill how long all your stuff can/will run...

Buy a 12v power adapter for your laptop.

Buy a 12v LCD/LED TV/DVD combo.

Ice-Box? Break down and get one that runs on propane.

8 Lamps? Have you thought any at all about LED's? They use less power and don't put out heat...

The money you save in panels and inverters should just about pay for the above stuff...

I'm not sure why you want 24v either... considering most stuff that is DC runs on 12v... Higher voltage means you can have longer cable runs with lower gauge cable, but for an RV I doubt it's even a concern.

Check out backwoodssolar dot com, they have a couple of sheets to help you figure out what you really need.

ohdeeremee · 03-26-2012, 02:21 PM

FWIW, over the last couple years I have replaced all my interior lights with LED replacements. Get the right kind, you get same or better light with about 1/4 power usage. Most of mine came from Star Lights (Porch LED Lighting | Automotive LED | Motion Lighting 12 Volt | Home | - Star Lights, Inc.).

Then I had to replace my batteries, one failed, so went with AGM sealed. Best price was at Sams Club and WalMart.

Decided to upgrade the solar part roughly $1000, and I did the work. You could double that if you had a dealer do it. Most of the stuff came from a place called Mr Solar (Solar Panels • Residential Solar Power Kits) : 2 each BP485J 12v solar panels, 4 each Flush Mount Kits (mounting brackets (I used 8 mount points per panel)), 1 each 72" #10/2 Intermodule Cable (between panels) , 1 each XX' #10/2 Output Cable (Length will depend on where you mount them.), 1 each SSD-25Rm 25 Amp 12 v Morningstar SunSaver Duo with Remote Meter (this is the solar controller with remote metering. From Home Depot or Lowes, a outdoor junction box, hole on bottom, 2 holes on side and matching removable water tight lid, (mounts on top of roof where old solar cable came out). From Bulk Wire (Bulk Wire: Online Shopping for Electrical Wire & Cable, Hookup Wire, Magnet Wire, Teflon Coated Wire, Red/Black Zip Cord) about 75 foot of #10 Red/Black Zip Cord. This is the important part. You need to replace the original solar wire with something heavier, and if I had to do it over again, I woudl use #8 in stead of #10. #10 is marginal for the lengths required. The Output Cable from Mr Solar is much too stiff to run from the roof to the bottom half of the HiLo. The wire bundle MUST be flexable, as it folds as the top is lowered. You have to take a lot of stuff apart, and it is a pain in the @$$ to get the #10 run. The zip cord runs from the junction box on the roof, down along the wire bundle (this depends on where yours is) thru the cabinet, behind the toilet, under the bathtub, into the refrigerator area. I had room (barely) to mount the remote part of the solar controller here. The zip cord goes from the roof junction box to the solar controller input. The output of the solar controller goes to the battery directly. Took me half a day to get this simple cable run. From the refer compartment, run along side the water and electric wires, under the tilt out, into the waterheater/pump compartment. Drilled a hole and used some vinyl tubing (1/2" ??) to protect the cable as it now goes under the chassis to the battery compartment. 30Amp fuse at the battery, just in case of shorts sometime (NAPA fuse holder, typical for car) Had to use a fishtape to get the wires thru the tilt out. Again, #8 would be better than #10 throughout, less voltage drop on that length of cable. The stuff that is in there is NOT heavy enough wire, too much loss, might burn it up with max charge. The remote meter for the solar controller is mounted next to the monitor panel by the refer. It comes with a 25' cable with RG 45 (??) telephone type connectors, they just plug in. Had to take the external shower panel apart, disconnect water temporarly, to get the cable run. That was another pain. Make sure you have new gaskets for the water connectors. You will also need some cable ties, a tube or two of RV calking (the kind that is UV resistant), about a week in good weather to do the work, ear plugs for the wife so she can't hear you swear. Probably some stuff I missed, but that is about it.

Here is some Pictures:
Roof 1 - Drivers side, solar panel. Black cable from panel to junction box. Note the 4 mounting feet. (8 total per panel) Panel must be at least an inch above roof for venting heat from bottom of panel. The feet mount to the panel with 1/4" Stainless steel bolts. For the 8 feet, I marked location, drilled a small (1/16" ?) hole to start Stainless Steel or Galvenized #10 x 1/2 hex head sheet metal screws, (CLEAN THE FOOT AREA) put lots of calk under each foot, some on the screw, (ya gotta have the cable attached first!) and screwed to roof. More calk on top of screw & foot, make sure it is a FULL seal around the foot. Look close on the picture of the roof, you can see some patches. These are where the screw holes for the old (I had 3) solar panels were. The patches are EternaBond 4" wide, by about 4" long for each old hole. Make sure you clean and rinse the areas for the new solar feet and any place the patches go. I used Simple Green (Phospher based) (Home Depot) and lots of paper towels. In fact, I cleaned rinsed this whole back half twice to make sure everything bonds with the roof, and just before I patched or mounted the panel, cleaned and rinsed again.

Roof 2 - Passenger side, solar panel and junction box. The individual solar cables run into this box. The box is located where the old solar cable came up through the roof.

Roof 3 - Junction box. Lots of calk under it. Has 4 screws into roof inside box. The black knobs came with the cables from Mr Solar, water tight rubber and plastic seals, plus my white calk around them. The box lid has 4 screws which I also calked. There is a single hole on the back side (not shown) opposite the 2 cables that I also sealed with calk. The box has a hole in the bottom and a cable clamp inside for the #10 Red/Black Zip cord.

Cable Bundle - You can see the vent pipe and the cable bundle. Because this flexes at roof, at cabinet, and in the middle, it needs to have flexable cable. The Mr Solar cable is 7 strand bendable (not flexable) and cannot be used here. The zip cord has 105 strands in it. I left a couple extra feet of zip cord in the cabinet incase it ever breaks at a flex.

(No Picture ) - From that cabinet (which you have to take apart), behind the toilet, under the bathtub, to the refer compartment.

Controller Mounting - This is the refer compartment. You can see in input and output Red/Black Zip Cord. The blue stuff is shrink tubing just to keep the zip cord from splitting apart. To the immediate right of the zip cord peeking thru the refer pipes you can see thte controller (black, white with some letters, and red strip) mounted sideways with a strip under the ends to allow venting underneath it. Tough place to work.

Remote Meter - Shows location I mounted it on the side of the cabinet by the refer. I did put a 1/4" wood backing plate inside for the screws that mount it. Another cabinet to take apart on the inside, both to run the remote cable, and the backing plate.

Cable Routing - Refer compartment is just behind the tires, then the tilt out, then the water compartment. Cable is on the interior of this part, then drops through the floor at the front (behind water heater). Watch out for the steel frame members when you drill here, plan ahead.

Battery Compartment - Here are the AGM batteries (2), the waterproof fuse with yellow wires and the red/black zip cord with an extra foot looped in a figure 8. Notice it goes through some 1/2" vinyl tubing and a black cable tie.

This is a 2507C if you want to look up the layout. The floor is about 20 foot long, Hilo measures from the hitch to the spare tire (25'). You can see why I used almost 75 foot of wire, I had about 10 ' left over. Get either 1 100' roll or 2 50' rolls if you mount the controller in the refer compartment like I did. What ever you do, you do not want to splice the cable!

(It appears that the HTF only lets me upload 5 files at a time. Will try to add the other 3 in another post.)

ohdeeremee · 03-26-2012, 02:23 PM

The last 3 pictures

RCREYES · 03-26-2012, 04:45 PM

Nice work!

sam · 03-26-2012, 09:05 PM

Thankyou for taking to share your modification and to post the pictures.

campthewestcoast · 03-27-2012, 01:12 AM

Nice mod, with the AGM batteries it looks like the sticker on top of the batteries says 55 AH so 2 batteries you get 110 AH? Why did you not go with 2-6volt batteries wired in series to get 12volts @ 235 AH? Was there a space issue in the battery box? How much were the AGM batteries? I also have a solar system but it's a maintainer system with one 33watt panel. Right now I have 2 newer deep cycle 12volt batteries that came on the trailer when I bought it.

ohdeeremee · 03-27-2012, 10:03 AM

Yep, the batteries are 55ah each. Wish they were 550ah.... I wanted AGMs and this was as close to a fit as I could get. Been using the equivalent size Interstate brand lead/acid rated about the same, and I do OK on them. The old ones were a deep cycle by Interstate, and they got drained to zip a couple times, and would only hold a partial charge. Refer controller when set to gas would sometimes kick on 12v at the same time. Only takes a couple hours to dump the batteries down to nothing. Fixed that with a new controller board, but that still left me with weak batteries, and only 3 years old. The AGMs are pricey, if I remember correctly, about $160 each at Sams.

I considered going with the golf cart 6v to get the 230ah, but they are BIG and heavy. Not enough room in the battery compartment without major rework. This one is in the V of the tongue. Would have to drop the compartment (which has the hydraulic lift pump also) down about 6 inches. Means I would have to rework hydraulic lines also, maybe even the electrical junction stuff. another project some day....

The solar charges around 6-7 amps max when batteries are REALLY low, at least now when the panels are fairly new. Gives me a fair charge time on the best of days, but only about 3 amps average. These are 85 watt panels, so have 170 watts in ideal conditions. Low sun mornings and evenings, hazy day, clouds, dirty panels, etc., and the charge rate drops quickly. I left room and connector space to add more solar panels. For another $1000 I could double the charge rate. Still have to carry the generator for those week long rains....

George

campthewestcoast · 03-27-2012, 08:40 PM

How much do your AGM batteries wiegh? I think the 6volt batteries are 60lbs each. Where you able to hit a roof rafter with the mounting screws when mounting the solar panels?

ohdeeremee · 03-28-2012, 09:17 AM

CTWC,
These are the Optima D34M series, 750CCA, weight is 43 each, specs here:

Optima BlueTop Specs - Deep Cycle Blue Top Battery Specifications by Optima

Others have a size issue in the battery compartment, if you change batteries, make sure you measure your space, it might be different than mine.

No I did not hit roof rafter, did hit a steel one on the J-Box, had to drill it to just under screw size to get screw in. The roof on this one seems to be 1/4" (or there abouts) plywood then aluminum on top. That is the reason I went with 8 screws instead of just 4 per panel, that and the calk acting like glue to hold them down. The three old ones (15W Sunsei SE-1200) had 6 #6 screws, and did OK, no pulling loose in wind, driving, etc. These are larger, so more screws. The mount position on the panel is not in the correct place to hit the rafters. Screws are long enough to go through the alum and ply, but not much more, as there is about an inch of foam insulation, no holding power there.

G

Motofixxer · 07-27-2013, 09:15 PM

Just as a quick helpful hint, I just posted pics of my extra battery mount to give some ideas. It's available here http://www.hilotrailerforum.com/f35/...ry-mount-3355/

ajc · 08-06-2014, 09:43 AM

yes if you wire them in parallel you will increase the amp hours 2 100ah batteries will give you 200ah
but that is in theory in reality you will only get about half thar

W9GFO · 04-20-2015, 06:46 PM

Quote:

Originally Posted by ajc

yes if you wire them in parallel you will increase the amp hours 2 100ah batteries will give you 200ah
but that is in theory in reality you will only get about half thar

I don't agree.

Two (good) batteries in parallel will double capacity. Maybe even more since since total capacity is affected by how quickly you draw the energy out. When you double the number of batteries you will be halving the current draw from each - that will give you a higher total capacity.