Rubicon Solar Power Experience (1 Viewer)

[LS1FJ40]

Thanks. That’s what I thought. I appreciate the confirmation.

It appears the 75/15 would be sufficient for my 160w Renogy panel. But if I wanted to add another panel down the road I should go to a 100/30?

 

[e9999]

Seems like it, whether you plan to run them in series or in parallel. The typical "12V" panel is open circuit something like 22V or so IIRC. So on the one side, you could put likely up to 3 in parallel voltage rating wise (only) with your 75/15. But, your one panel at 160W would give up to about 11A on the downstream side at about 14.5V. So, the 75/15 is rated indeed high enough for one, regardless of whether the "15A" rating applies to upstream or downstream (I don't know). I'll assume it's downstream since that is likely the higher current side. So, a 100/30A controller would be enough for 2 of your panels in series, both voltage (22 or 44V) and current wise (22A downstream). But a 15A (if that means downstream) would not be enough for 2 panels (at 22A downstream), even if put in parallel. I'm tired so somebody check all those numbers if you even care...
Personally, I would generally favor the parallel setting: higher voltage, less current, fewer losses, maybe fewer issues with dead spots, more excitement when you short yourself ( ) but you still have to deal with higher currents on the low voltage side whether parallel or series. So, yes, seems to me you need the 100/30 over the 75/15 for 2 panels.

 

[Cruiserdrew]

Why would you add another panel down the road? How much power do you need? Think about it, you have a fridge, and maybe a few other things. You need more than one 160 watt panel? Go big then. But if you're running one panel. one fridge (or two in my experience), 2 batteries, you are good to go.

Once you're into more panels, more batteries, you are no longer travelling in your Land Cruiser. Instead, you're in an RV, using tons of power and no longer in the Land Cruiser universe.

@e9999 should remember his engineering principals. You use what works. Once you need to go big, do that. But really you will find, for normal Land Cruiser travels, 160 watts will serve all of your needs. Even 100 watts is sufficient for most installs.

 

[george_tlc]

^ Agreed. A trip a couple of years ago saw us camping in temps that were reaching 110F in the day - nasty. Anyhow, an 80W panel was keeping up with our arb 50qt's daily amp.hour usage and keeping food/drinks plenty cold - cold enough to have some slushy drinks... This when we would stop & camp for a couple of days. No issue topping the aux bat back up to 100% well before lunchtime the next day and then keeping it at 100% until sunset. This was ensuring the panel was facing the sun and not being shaded.

160W would be more than sufficient - overkill most of the time except if the weather is hot AND seriously overcast. Might also be appropriate if the panel is hard mounted and can't be positioned optimally, in this case some of that extra capacity can be traded against poor positioning.

Though, we did have some overcast days and the 80W panel was still pushing a couple of amps into the battery, still enough to keep up with the ARB's amp.hour demands.

Of course this also assumes you are 4wd camping versus some kind of glamping or using a 2nd fridge to keep buckets of icecream frozen...

cheers,
george.

 

[concretejungle]

I am running two, 60W panels and so far it has given me all the power i need for my camping setup. Fridge, radio/stereo, recharging RC and drone batteries, phone recharging.... i've even set up (on a full sunny day at the beach) a crock pot through my inverter and cooked a pork butt for almost 6 hours using the panel.

I started with one 60W panel and it just didn't quite cut it. Two... or one 120W Panel is plenty IMHO

 

[e9999]

yes, Andy, 100W should be sufficient for most LC trips. That is not, however, the question that LS asked. It is smart for somebody to ask if buying a given controller could be a limiting factor for other -and maybe different- applications down the road. "Thinking ahead": another Engineering principle, maybe?

 

[LS1FJ40]

Got the 160w panel mounted yesterday. Also swapped the wiring to MC4 connections and 12 ga instead of 14.

I have it hard mounted, for now. I thought about a mounting system to be able to tilt it but figure I should be ok with it being hard mounted. Size is 59”x27”.

 

[Cruiserdrew]

Just make sure those rack side bars don't throw shadows on your panel. Even small bits of shade will kill the output from that string of cells.

 

[concretejungle]

Just make sure those rack side bars don't throw shadows on your panel. Even small bits of shade will kill the output from that string of cells.

This is so true! Put a volt meter on that sucker and shade just a tiny bit and watch the drop! It's astounding

 

[LS1FJ40]

Just make sure those rack side bars don't throw shadows on your panel. Even small bits of shade will kill the output from that string of cells.

Yep. The rack is getting chopped once I finally figure everything out as far as set up. Work in progress.

 

[e9999]

Personally, I would be hesitant to use a good chunk of my roof rack for a panel, that is normally prime real estate for long road trips. And one does not normally need the panel when driving -unless you want to absolutely maximize mpg maybe- so storing it inside and pulling it out when stationary would usually be a good tradeoff for me if that frees up the whole roof rack for travel. But to each his own, of course. Maybe putting it on top of a fairly low storage box on the roof rack would be a good compromise.

 

[GLTHFJ60]

I assume that the solar panel functions as a soft of battery tender when not running the truck for long periods? Thinking about it more, that's essentially what this is, a super-sized "off the grid" battery tender.

I'm about building a lightweight roof rack to hold some stuff that rarely gets accessed, and this thread is making me think that adding a large solar panel is a no-brainer.

 

[LS1FJ40]

Personally, I would be hesitant to use a good chunk of my roof rack for a panel, that is normally prime real estate for long road trips. And one does not normally need the panel when driving -unless you want to absolutely maximize mpg maybe- so storing it inside and pulling it out when stationary would usually be a good tradeoff for me if that frees up the whole roof rack for travel. But to each his own, of course. Maybe putting it on top of a fairly low storage box on the roof rack would be a good compromise.

Personally, I don’t like traveling with stuff on my roof. Other than my canoe. I just find it difficult to access. Difficult to secure. And the risk of increasing the COG. But I usually travel with just my son and I.

Yesterday was he first full day with it on.

I need to get that Vitron controller so I can monitor. Not that I really NEED it. My Morningstar Sun Saver is plenty good but it would be kind of interesting to know what I’m getting.

 

[LS1FJ40]

I assume that the solar panel functions as a soft of battery tender when not running the truck for long periods? Thinking about it more, that's essentially what this is, a super-sized "off the grid" battery tender.

I'm about building a lightweight roof rack to hold some stuff that rarely gets accessed, and this thread is making me think that adding a large solar panel is a no-brainer.

Yes. You need one.

 

[Cruiserdrew]

I assume that the solar panel functions as a soft of battery tender when not running the truck for long periods? Thinking about it more, that's essentially what this is, a super-sized "off the grid" battery tender.

That's a pretty fair characterization, just with far more power on tap. And, if you use the Victron controller-you can configure the voltages that you want for absorb and float, as well as the duration of the Absorb phase.

And with regards to the battery tender aspects, I leave mine running all the time, and the 60 and 62 are tied together electrically when parked, so it's doing quadraduty and maintaining all 4 batteries with an exact schedule that's temperature compensated.

 

[Semi Hex]

I have my 180 watt Grape panel permanently mounted on my teardrop. I really like that it charges all day long instead of me having to set it up at the end of the day. Like Drew, it can charge all my batteries if needed.

 

[e9999]

It is true that is likely that a FLA battery kept topped off all the time may live a longer and happier life. That would be a plus to having a panel up there all the time. Now if the charge controller would have some sort of (effective) desulfating system built-in, even better...

 

[Cruiserdrew]

It is true that is likely that a FLA battery kept topped off all the time may live a longer and happier life. That would be a plus to having a panel up there all the time. Now if the charge controller would have some sort of (effective) desulfating system built-in, even better...

It sort of does if you use the "equalize" function. I have experimented with this a bit, it seems to do something, but not sure exactly what. I may set it to equalize once per month or something. It's relatively gentle and while you can see the bubbles of electrolysis, you would not have to remove the cap. I just went through the batteries in prep for Rubithon 2018. Equalized at 15.2 volts for about 1 hour, then made sure the cells were all full. Both batteries are 3 year batteries, one is 4 years old and the other is 5. They are still working well. The key is the constant charge, and routine (every 3 months) water/electrolyte checks.

 

[concretejungle]

Cruiserdrew, what electrolyte do you add? Gatorade?! haha joke. I was wondering that very thing the other day when looking at my battery. If it is low on fluid i was going to just add distilled water... is that not correct?

 

[Cruiserdrew]

Yep. Distilled water only.

If you try Gatorade, please report back