Question For RedRock Tracker users.

[RCpilot]

I have a Redrock Tracker and so far it's working good but I don't want to charge it's battery every few days. What I would like to know from any of you using one is what size Gel cell you are using and how small of a solar panel you use to keep the battery charged? My Actuator is From Channel master, as the whole Satellite mount is a Channel master and I don't have any details of the actuator other than it's 18" of travel, has a 2" OD and inside has a single switch that is opened and closed by a rotating square attached to the lead screw. I don't use the switch, I am using a pair attached to the mount itself. Check my diary I have pictures of the actuator. I plan to build whatever size panel most use, from what I have read, around 10W or so. I just haven't seen many posts that say what size battery everyone is using.  

[veewee77]

Dumb question. . . Why not use the batteries you are charging to provide power to the tracking system?  Doing the voltage conversion (if necessary) should be straightforward, and at most you'd just need a second pair of decent sized wires (12 or 14 would probably work if it weren't too far) from the battery bank back out to the tracker unit unless the batteries are already out there. This is how I am going to do mine when I get around to it. . .

Doug

[RCpilot]

Unfortunately, not being able to plan well, I have already ran my wires across the yard and everything is buried. It's 80' from battery to the panel mount. I read that many people just use a small panel and a small gel cell to power the system.

[TomW]

RC;

Well, if they are PV panels then you have DC going to your batteries why not just tap that? Maybe thats too obvious and I miss something like you have diodes on both ends of your PV to batteries cable?

I think you failed to differentiate between solar tracking for heat and PV. RedRok seems geared to the heliostat crowd [heat gathering] and they would rely on an external voltage source. You, however, already have a voltage source.

Cheers.

TomW

[Sparky01]

Yes, I use the power that is right at the panels to power the tracker. I will have to run dedicated wires later or a DC to DC converter scince I will be adding those panels to my MPPT controler and now my voltage will be at 60VDC nominal instead of at 12V like it is now. So it depends on what you are using for a charge controler and at what voltage you have at the panels.

[Volvo farmer]

Did you run the wires in conduit? My array is probably 40' from my batteries. I wanted to use battery power and I was able to jerk all the wire out of the conduit, tie some 12/3 romex to it, and pull it all back through. I think it was well worth it, since it takes the worry out of maintaining another panel and battery.

I did have some experience with panels and batteries before I did this though. I had a 5W thin film panel and a pretty big gel cell (maybe 30AH?) on my garage tracker and it worked fine for about a year with no fiddling. This is a pretty small array though, only two 80W panels.

I had a couple of cheap 2W panels and a couple of batteries in the 15-18Ahr range on my big array, all wired for 24V, The panels were not keeping the batteries fully charged and they would need attention every couple weeks. This was the situation that prompted me to run the wires straight out from the battery. The nice thing about this setup was that I was able to tie a second tracker right into the first and I already had 24V there for power. My panels are at 48V so they are out of the redrok operating specs.

[PaulJ]

   I use a 12V 36Ah gel to power mine, charge it with a regulated 60W panel once a month or so. This is with a smaller actuator than yours, moving 330W of panels.

   Paul.

[ghurd]

Maybe I'm oversimplifying it.  

Why not use the main PVs to charge the small battery?

With a 12V system, connect the output of the PVs to a PB137ACV (Small TO-220 battery charger chip), feed the output of that to the small battery.

For a 24 or 48V system, connect the PB137ACV to one 12V PV in the string. Probably the one that connects directly to ground, instead of the middle or higher voltage-to-ground PVs.  I think it would have about the same negative effect as a bypass diode that was partially and occasionally conducting, so not much.

I wouldn't try it with 2 fancy controllers.  But I don't believe the simple PB137ACV would interfere with the operation of the main controller.

G-

[RCpilot]

Guys thanks for all the excellent ideas. I ran 3/4" pvc conduit and 4 #8 wires in it. the wires fit but only if I made sure that they weren't crossed and were in the conduit like this :: The were tough to pull and if I had to do it over again I would have used 1" conduit. I am saving a pair of #8 wires for future panels. I know, I could use them right now.. It would be pretty tough to pull it all out and try to add a couple of #12 or #14 in it. As some have said, run it from the existing panels. I could do that too but I really like the idea of just powering it from the main battery as that eliminates a panel and battery sitting out in the sub freezing weather we get in the winter. I will probably just run another conduit so I don't have to mess with the first one and pull some small wires with extras. That seems the simplest idea and the extra conduit 1/2 wont' cost more than about $20 or so. Wire, I can get that pretty much free from a salvage yard down the road from me. I help the owner with PC problems and he will give me "Junk" So, I think I will scratch the extra panel and battery. More digging tomorrow! Thanks everyone!

[coldspot]

Thanks everyone this was good info!!!



I have a RedRock, two LED type,(cute little bug looking guy I named it "ROK" for rocking my panels,,..LOL!) still unused/tested but plan on using it to power an automotive window regulator @ 12VDC on my small scale PV set-up going with a pipe in pipe tri-pod base mount. Turning the outer pipe,with the power window motor and its tray slide, this will have the PV's attached to it. I haven't picked the cable type over the rack with gear type teeth yet. I have both and either one could be used without a lot of effort.

 I will be sure to run extra wire for power back to the tracking motor and being that I also have an old dish mover, I might use that for manual seasonal adjustments and it would need power at the base also.

Thanks

$0.02

 

[Volvo farmer]

I paid a solar installer a good price to wire up this system, luckilly, I got to look over his shoulder and will never have to hire him again.

One thing I got for all my money was his experience, and we ran 1.5" conduit from the panels to the battery. The difference between 1.5" and 3/4" materials is marginal, digging another trench and laying more conduit sucks, but it's the lesson of experience, you pay one way or the other :-)

[TomW]

Volvo ;

Yeah, the cost difference was minimal here and I went for 2" over 1" when 1" would have "worked". Now I have an underutilized space in my conduit so I can upgrade any time with no digging. I also pulled a strong cord thru with the cable so it will be easy to pull new stuff.

Just seemed wise at the time. I hate digging.

Cheers.

TomW.

[RCpilot]

I wish I could afford to pay someone to install a $10-20,000 or so for a turnkey system. Cost is the biggest factor in why I am attempting to do as much myself as possible including building the solar panels, dealing with a salvage yard to obtain wire, pipe, disconnects, breaker panels etc. Unfortunately making occasional bad decisions is part of the learning process of doing it ourselves. I still may decide to run the tracker from a small panel, I have the cells already, they cost me $25 for enough to build a 12 watt panel. I was needing to know about how big of a battery would be needed but nobody even touched the question. I'm still hoping there might be a few members that used this method of running their trackers that could give me an overview of their setup. I can get, free, brand new, any small size gel cells from my son in law so not much cost is involved in running the tracker from an external source other than the main array. I thought about running it from the main array but wondered how my main charge controller might behave with another smaller circuit attached to the same panels. I am thinking that something like a 18AH UPS battery would be enough to cover the need even with a few cloudy days. Anyone?

[PaulJ]

   An 18Ah gel with a 12W panel permanently connected should be plenty; my 36A gel can last a month between charges in a similar application (although that's probably cycling the battery pretty hard). You'll need some sort of regulator I think.

   Paul.

[RCpilot]

Thanks Paul, I have a small 16A charge controller I bought earlier in the year when I was experimenting with a 50W panel. Since it's just sitting I plan to use it. It's overkill I guess but just sitting so it needs a home.

Thanks, Kelly

[Bruce S]

RCpilot;

  I am nowhere near to size that you and others have, however, if you do go with an external panel and would like some sub-c NiCds that will take the freezing cold where most others will not, let me know and I can ship anough for you to build up a good size bank. These can take down to -20C , of course there's a few things to consider but the price is right :-) = free.

Just a thought

Bruce S

[RCpilot]

What an offer! Bruce, that is very generous and I would take you up on it except I just, today, mounted up a much better "Tracker" controller that includes a 22AH Gel Cell battery and a 16 amp charge control that also has a temp probe to mount on the battery. The Box is a larger outdoor breaker box I gutted and mounted everything inside. I included switches to allow Auto/Manual movement of the actuator. The battery even has a 3/4" layer of blue foam around it, sealing it within. That should help protect it a bit from the bitter winters here. I am overkilling the charge of it with a 50 watt panel but I had it laying around unused and, as long as the battery remains charged, it should be ok. I plan to build a 20 watt or so panel for the final charger but the other panel will work for now. I wish you would have offered these about a week ago, the 22AH battery was given to me also and is very new. I also built from scratch a acrylic box to mount my LED3X inside and installed that as well. It got dark so I couldn't get pictures but will tomorrow and add to my files. I just love to see other's setups as it usually gives me good ideas and also shows how others do things. Thanks again Bruce!!

Kelly

[RCpilot]

Paul, do you have pictures of your setup?