Solar Panel Upgrade on 2012 Interstate

[KevininTX]

Looking for some help.

I have the stock 50W solar panel on my 2012 Interstate and on the best of days I get about 2.5 amps according to my monitor which means it has degraded quite a bit. Plus, I'd like to upsize it anyway.

I'm seeing good pricing on (12V) 200W panels that would fit on the rooftop nicely. Is this pretty much a plug and play, or would I need to change wiring and other hardware to go up to a panel rated at 4X the output?

Any suggestions from those in the know would be greatly appreciated!

Kevin in Houston, TX

[InterBlog]

Hi Kevin in Houston. I am also in Houston (League City).

Channeling Steven Covey, begin with the end in mind. To better answer your question, what is your end goal? Do you want to do a quick and dirty upgrade that will get you a bit more power and then you plan to be done with it? Or is this possibly a step in the direction of larger upgrades? In other words, how likely are you to be bitten by the DIY bug?


My husband and I fell hard into the latter category and ended up making our Interstate essentially off-grid (except we can’t run our roof a/c but I don’t want to be traveling in areas where I need it because that would be too danged hot to enjoy, so I am good with that). I wish we had been able to plan that journey better than we did, but our inefficiency was mostly not our fault because years ago when we started, all power upgrades had to be DIY because there were no suitable products in the consumer market. That changed radically just within the past 3 years or so.

Anyway, I won’t go too far off on that tangent just yet because it would be more useful for me to first hear your answer to that question.

Meanwhile, here is our current eye candy, at least the roof portion:

[KevininTX]

Thanks for the quick response!

For the moment, I think I'm just looking for the quick-n-dirty, but you make an excellent point, and down the road I likely will be making my rig into a more robust off-grid camper!

The immediate...

I have a 4-day event coming up in 2 weeks in Oklahoma where I'll be completely off-grid. My 2 lead-acid batteries are about 3 years old, so they do fairly well, though certainly not well enough to use the refrigerator! I can live w/o fridge and if I do lights, water pump, and fan (for heater) only I think I can almost get by...and if necessary, I've got the generator to charge things up for a couple hours.

But that's the problem here... I'm not sure I'll be able to run the generator at this event at all--lots of neighbors and most are in tents. And if so, I'm thinking that having 200W from a NEW rooftop panel would almost certainly keep me charged up for the 4-days assuming average amount of sunlight.

So, could something like this just be put on in place of my current 14-yr old BP panel?

https://www.renogy.com/200-watt-12-v...-cleRGuB_ZV4Sk

Thanks!

Kevin in Houston, Texas

[InterBlog]

Originally Posted by KevininTX

…

…I have a 4-day event coming up in 2 weeks in Oklahoma where I'll be completely off-grid. My 2 lead-acid batteries are about 3 years old, so they do fairly well, though certainly not well enough to use the refrigerator! …

….

Ok, this is good context - you have established yourself as someone who intends to use their rig beyond the catatonic approach of idly driving from state park to state park. Whether the event you cite is for work or pleasure, you are invoking a higher level of vehicle reliance than many (if not most) owners.

If I were you — and I am not — I would increase the solar to at least 400 watts and eventually migrate onto a removable lithium power pack with an aspect ratio that can be accommodated somewhere within the vehicle.

Neither of those things ^^ are likely to be achievable in a 2-week timeframe if you are a working person (non-retired with limited time to work on the van).

So, back to your original question - can you retrofit a panel?

Two weeks from now is the third week of November when the sun is wretchedly low in the sky (i.e., four weeks shy of the annual solar minimums). Even if you do a single-panel retrofit and it’s electrically compatible, my empirical wisdom is suggesting that you won’t get enough juice to keep your fridge running for 4 days off grid even if the sun does shine, which in late November is a crap shoot across most of this country.

Not with AGMs at least, but there’s another strategy that might work. If you think that you are going to be upgrading your system eventually, what you COULD do is scope and purchase your new removable house battery pack NOW (pricey + requires research but maybe strike a pre-Black Friday deal). Make sure you pick one that can power your fridge via 12 volts so that you do not need to waste energy inverting. Leave home with that thing 100% charged and plan to run your refrigerator off that supplemental pack, and the rest of your van off the existing house power (which it will easily handle because the fridge is the big booger in the consumption equation), and then worry about your solar augmentation later.

^^ THAT should be doable for 4 days off grid at this time of year, if you are OK with paying for the supplemental battery that you are likely going to need eventually anyway if you use your Interstate to its maximum potential.

[StogieMan]

InterBlog is correct. I think that you need to either commit now and plan for the future or frustrate yourself and say “Could’a, would’a and should’a". I’ve been there and regret it. You can get away with just replacing the solar side without committing to the battery side just yet. Going lithium is another rabbit hole that you really need to do some research on and be comfortable with but I highly recommend it.

So the answer - pretty much plug and play if you don’t replace the original solar charge controller.

However, it’s never that simple. If you still have the flexible solar panel up there it’s definitely past its prime and you should replace it. If you’re going to replace the panels, you should also replace the Airstream Atkinson solar charge controller while you’re at it with a Victron Bluetooth one. That Atkinson Airstream one is complete junk and many folks will concur with me. This is the part that will probably take the most work as Airstream installs it buried somewhere in a hard to get area.

I would also redo the SAE connection while at it on the roof as it’s probably become corroded over the years. You can pull the connection off and check.

If I remember correctly, the yellow and green solar wires going up to the roof and at the Atkinson charge controller should be either 10 or 12 gauge which is fine for a 200 w solar panel. IMO the max that you can get up on an Interstate roof is 400 watts. However, companies are always making newer panels so that may change so do your research.

PS - I highly doubt that you’re running that fridge for four days on a 200 watt solar panel. Another possible option is to add a separate solar ground array but that’s entirely a whole different rabbit hole.

[InterBlog]

Originally Posted by StogieMan

…. If you’re going to replace the panels, you should also replace the Airstream Atkinson solar charge controller while you’re at it with a Victron Bluetooth one. That Atkinson Airstream one is complete junk and many folks will concur with me. This is the part that will probably take the most work as Airstream installs it buried somewhere in a hard to get area.

I would also redo the SAE connection while at it on the roof as it’s probably become corroded over the years. …..

But the paradigm shift is that the consumer market has now evolved to the point where we could, if we wanted, ***ABANDON THE ENTIRE OEM SYSTEM*** and just adapt an off-the-shelf solution to power everything on the house side of our vans!

In other words, forget about charge controllers. Forget about external inverters. Forget about the delicate art of lithium cell charge balancing and the whole bloody mess, because there are now complete portable boxes for sale out there that do it all for you, and not only that, they do it well.

My Interstate’s little CargoMate trailer has 600 watts of solar mounted on its roof. I have ONE WIRE running from those panels into the EcoFlow DeltaPro power station that powers my Engel freezer and many other things. It’s plug and play, just that simple. This is the future of everything.

And this is mind-boggling for those of us who came up through the era of needing an engineering degree to design our own systems. But there is zero question in my mind what my van will be migrating to, whether it’s our current Interstate or a future DIY van that we may build - our lithium power center will be modular and we will remove it from the van for storage in an air conditioned space because we have learned the painfully hard way that we cannot permanently install lithium in a vehicle that spends almost all its time in the Deep South and expect those batteries to maintain their integrity. It’s just so hot here that it cuts expected battery life about in half (Kevin, are you following this?!). We have to be able to pop our battery systems out of our vans and tote them into our houses the same way we empty our refrigerators at the end of a trip. No question at all in my mind about this because I’ve seen what chronic Houston heat has done to our original lithium installation and it’s shocking. Ugly.

Anyway, there’s an impassioned speech from me. Not too often those are inspired on Sprinter and B Van Forum these days.

[KevininTX]

Originally Posted by InterBlog

But the paradigm shift is that the consumer market has now evolved to the point where we could, if we wanted, ***ABANDON THE ENTIRE OEM SYSTEM*** and just adapt an off-the-shelf solution to power everything on the house side of our vans!

<snip>

Anyway, there’s an impassioned speech from me. Not too often those are inspired on Sprinter and B Van Forum these days.

Wow! Thanks for all the great feedback from both of you here! LOTS to think about, and the good news, my 2-week timeline is no more!

First off, sorry about the slow response--I didn't mention earlier that I'd be going off on a motorcycle trip! I'm back now, and getting back to planning the next trip!

Second, as just mentioned, I no longer have a tight schedule! Turns out, the organizers at this upcoming (large) event lowered the price for their very limited (20) RV spots to a more fair price-point, so I'll be plugged in for this one!!

You guys have given me a lot to think about. I have 2 relatively new lead acid batteries now, and in an ideal world I'd love to have a set-up where I don't have to go to the cost and complexity of changing EVERYTHING up. And pulling lithium batteries out doesn't sound that easy--especially as my current ones are stacked and the seat across the back of the van must be partially disassembled to even get to them! (Yes, realize I'd jetison that setup, but seeing a LOT of work regardless!)

Also, my wife and I ARE largely the "one state park to the next" type that InterBlog described before. She enjoys the community aspects of camping with like-minded neighbors, walking our dog around the loop, and so on, so all this is overkill and really not even needed for 90% of our usage.

The fly in the ointment is ME--I have an adventure motorcycle that I tow to "guys weekends" where we ride ridiculously large, 600-lb motorcycles in places and trails best suited to small 250-cc bikes!! This is where a robust, off-grid RV would be awesome! However, I do just 2-3 of these a year, so spending $5K to optimize for these trips probably doesn't make sense.

One more angle, I have a nice Onan 2500 W generator that can be my "no sun today" backup to charge up my dinky little batteries. Plus, nice as the fridge is, I can always put everything in a Yeti ice chest on these guy weekends and just forego the fridge--the LED lights, heater fan (if cold outside), fan-tastic fan (if hot) don't use that much power....

Sorry, I realize I'm rambling, but you guys have given me a lot to think about....

InterBlog - Seeing that we are both in the Houston area, one of my favorite breweries is Texas Leaguer which is down your way. Maybe we could meet there sometime and I could pick your brain some on all this? Would even drive my Interstate down if it made sense! And beer would be on me, of course!!

[InterBlog]

Originally Posted by KevininTX

….. pulling lithium batteries out doesn't sound that easy--…

Paradigm shift: it’s as easy as pie because they are on wheels. Have a second person help you with the lift off the ground and into the van, but otherwise just roll that puppy around, the WHOLE SYSTEM, into a dock within the van. Take it out and store in air conditioning when done with the trip.

Illustration - on another thread called “Ten Years in an Interstate and Finally a Home”, I’m all happy clappy about the house that my husband and I just built, but back in July of this year when Hurricane Beryl hit, we were still in a miserable 600 square foot apartment waiting for the builder to complete our property (we sold our previous home to free up the cash ahead of the new one).

Like 85% of Houstonians, we lost power during Beryl and did not get it back for some time. In the pic below, you can see my EcoFlow DeltaPro system (not just battery) running the full-sized apartment refrigerator with a lamp on top just so I could see inside the apartment version of the black hole of Calcutta. It’s self-contained with a case and it’s on wheels with a retractable handle. It is heavy, yes, but two people make short work of it.

I bought the DeltaPro at Costco right when prices started to plummet. It has the wrong form factor for integration into our Interstate (too long and narrow) but I could not resist, especially because I can use it in our trailer to power my big Engel freezer. I could power a small cottage with that thing, rolling it around like airport carry-on baggage. That’s the future I’m talking about.

And yes, in this picture it is sporting its overcoat (what Boxster warned about) but I will fix the ventilation panels. EDIT: I meant to say, Boxster warned about the Engel but from that information, I now assume that the same hazard exists for other similar products.

[Rig Rat]

Do you have a battery vent opening to your coach AGM's? We do in our 15 lounge and initially bought a 200w portable suitcase to charge our batteries each day. After a few years, we added 300W of fixed solar to our roof as well as a lithium power station to supplement our power needs when off grid.

[KevininTX]

Originally Posted by Rig Rat

Do you have a battery vent opening to your coach AGM's? <snip>

Yes, I have the battery vent in the exact same spot on my 2012 and the batteries are stacked--1 at floor level, and the other below the floor in a metal box.

Funny story on this--when I bought this unit 3 yrs ago the owner (who was 2nd owner) told me how he'd just replaced the coach battery (singular). I'd been doing some research and thought I'd heard folks talk about 2 coach batteries, so I asked. He went on to open the back door and show me how there is only 1 battery and you could see from where we were looking there was only room for 1 battery, so I accepted it as the gospel.

A few months later, on this forum in someone's post related to battery life I mentioned something about some units like mine only have 1 coach battery. Immediately, I was challenged and by several folks and one that had a 2012 just like mine!

So, I went out and pulled the seatback off (to gain access) wondering how this could be?!? I then pulled the new battery out, and immedately could see the 2nd battery underneath which I am sure was the original (8 yr old) battery from the factory!! The previous owner (or his mechanic) never even noticed it when replacing the top chassis battery!


Needless to say, performance went up DRAMATICALLY after putting a 2nd new battery in!

KevininTexas

[broyston]

I did a solar & battery upgrade to our Interstate. Removed the 50 watt panel and put 350 watts up there. Replaced the existing batteries with two lithium batteries. Total game changer. Absolutely love it. Highly recommended.