Off-The-Grid Solar Setup Needs a Dummy Check | OVERLAND BOUND COMMUNITY

Off-The-Grid Solar Setup Needs a Dummy Check

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kithound

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Hey all,

Gonna be spending some more time on the road soon, and I thought before I did I would install an auxiliary battery/solar setup for the Monty. I was initially thinking of getting a Goal Zero setup, Yeti 400 + Nomad, but the $750+ price tag has me exploring other options, and the idea of doing it for ~$250 and the satisfaction of doing it myself sounds great. That said, I know about as much about wiring as my dog knows about 18th century French literature, so I figured I'd see if somebody could dummy check my logic.

IMG_4259.jpeg
Current situation – 1999 Montero Winter Package with a few mods left to go.

Bottom Line Up Front

Power needs:
  • Continuous power to DashCam
  • As-needed charging of Laptops, Camera Batteries, Cell Phones, etc.
  • Potentially powering a cheap fridge/freezer combo to be added later on (Costway or similar)
Shopping List:

TL;DR Questions:
  • Is that enough juice (both from the inverter and the panels)
  • Are those cables correct?
  • Do I need the SB50 Connector Kit?
  • Do I need a better-brand controller, or are the included ones OK?
  • Can I leave the end of the extension cables exposed on the entry gland, so I can detach the panels at will?
For those with charitable hearts and more time than sense, here's the game plan in more detail. Buckle up, this one's the product of my underemployed, over-caffeinated ass trying his best to be thorough on a topic he doesn't know much about.

I'm running off of this Outside Magazine article, with a couple modifications. For clarity's sake, I'll start from the panels and work down.

The article uses rigid, permanently-affixed Renogy panels, but I'd prefer using flexible ones that I can keep in the vehicle when not in use. I would make a Cordura pouch for them that closes with velcro to store them. I found these on eBay, but if anybody has an alternate vendor they can recommend please chime in. Not sure if I'd need one or two, but for less than 50 bucks apiece, two seems pretty good. That said, they include a solar controller, with amperage options ranging from 10A to 40A, and this is where my knowledge starts to show its shortcomings. What Amperage should I grab? It looks like a minimal difference in price.

So the panels, which I'd wire together in tandem using this Y-connector, would have their own pouch and that would be one self-contained component of the system. From there, I'd fit the roof with this cable entry gland, which would then be fitted with 20 feet of 10AWG solar extension cables. I'd planned on leaving just the input ends exposed on the roof, so that I could connect and disconnect the panels at will, but if this is a bad idea, please let me know any alternate recommendations. I'd like to be able to take the panels off when I'm parked in the city, for example.

The 10AWG cable would run through the headliner and down to where my soon-to-be-removed CD changer resides, where it would re-emerge and be connected to... well, I'm not sure. According to the Outside Mag guide, I'd hook them to the SB50 Connector, but I'm assuming I could just plug them into the controller included with the solar panels, right? Again, I should point out my knowledge of electrical systems parallels my dog's knowledge of the works of Beaumarchais.

Assuming the controller with the panels is good enough, I'd then run a long micro-usb through the carpet and back up to the headliner to power the Dashcam (question here: would that power line then be dependent on the solar trickle, or could it run off of the battery I wind up connecting it to?). Battery would go in whatever plastic box I can dig up.

Then from the other ports in the controller, I'd run these 2AWG battery cables to a deep cycle, 35AH Mighty Max battery.

I'd bore some holes the other side of the box 12V adapters, which include cables – hopefully sufficient for the application.

In one of the 12V adapters, I'd plug this BESTEK 300W inverter, which I'd secure to the top of the ammo can with hook and loop so I can keep it in place while driving or reposition it outside the truck if I want to charge my laptop at camp. The other 12V port would either be kept free for powering incidental stuff like compressors or, if the mini-USB-to-controller idea wouldn't work, be fitted with a dual-USB phone charger that I'd plug the dashcam into.

And I think that's that. Phew. We made it. Let's have a glass of single malt to celebrate the journey and kick the tires on this wiring plan. If anybody can steer me away from any mistakes I've made, call out things I've forgotten, etc., I'd appreciate it greatly. Things like "Not gonna work, that wire won't fit your controller," or "Make sure you wrap everything in X or you'll set your car on fire."

Thanks in advance, all!
 

leeloo

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If you want the dash cam powered non stop connect it to the start battery. I asume you want to use the motion activated security feature on it. It does not draw a lot of power, it is safe to use unless you don't start your vehicle for weeks..
The 35 AH battery is too small because it is lead acid. That means out of those 35 AH you might be able to use half of it, aprox 17 amps. Not enough to power a fridge a hot night, let alone an inverter and other things..
read here
For you can go with option A described there, since your vehicle is 1999, but measure your alternator before it. If you get a bigger battery, even if it is a cheaper lead acid, make sure it is deep cycle. If it is big enough , like 80 minimum 100 AH ideal for your needs, you might not even need solar at all. YOu can get only the VSR and the battery + cables and do a test. If it is not enough, you might camp for 2-3 days in a spot, without an engine start, than you add solar.
If you look on the sites there at the premade wiring kits, you get an idea of what you need as cables, fuses, fuse boxes etc.. and buy them from you local store..
A 100 W panel with a 10 amp mppt controller will do. Like I wrote there, for any outside connections exposed to the elements use a DT series or otherwise know a Deutsche plug..
 
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MOAK

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Leeloo is correct. Look, the OP mentioned cost. For what you are doing, don’t cheap out or you’ll be very disappointed on your first trip. In order for your system to work you’ll need at the very minimum a 100 watt panel, a 60 amp hour deep cycle battery, and a medium priced charge controller. That’s the minimum. That’ll work on a perfect sunshine day. If you’re looking to set up in the woods with spotty sun, or perhaps an overcast or rainy day, then you’ll be needing to double that capacity, meaning another 100 watts and 60 more amp hours of storage and at least a 20 amp controller. Oh, not to mention, the cheapo controllers are garbage. Get a good one, do your research. My system may be overbuilt as I’m running two fridges, and charging camera batteries, etc etc, but I can camp almost anywhere and have enough energy storage to last a couple of rainy days if need be. Good luck
 
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Savin yours

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Leeloo is correct. Look, the OP mentioned cost. For what you are doing, don’t cheap out or you’ll be very disappointed on your first trip. In order for your system to work you’ll need at the very minimum a 100 watt panel, a 60 amp hour deep cycle battery, and a medium priced charge controller. That’s the minimum. That’ll work on a perfect sunshine day. If you’re looking to set up in the woods with spotty sun, or perhaps an overcast or rainy day, then you’ll be needing to double that capacity, meaning another 100 watts and 60 more amp hours of storage and at least a 20 amp controller. Oh, not to mention, the cheapo controllers are garbage. Get a good one, do your research. My system may be overbuilt as I’m running two fridges, and charging camera batteries, etc etc, but I can camp almost anywhere and have enough energy storage to last a couple of rainy days if need be. Good luck
When you say, the cheap controllers are garbage...what should we be looking for? Brand? Price? Features? Safety?
 

kithound

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If you want the dash cam powered non stop connect it to the start battery. I asume you want to use the motion activated security feature on it. It does not draw a lot of power, it is safe to use unless you don't start your vehicle for weeks..
The 35 AH battery is too small because it is lead acid. That means out of those 35 AH you might be able to use half of it, aprox 17 amps. Not enough to power a fridge a hot night, let alone an inverter and other things..
read here
For you can go with option A described there, since your vehicle is 1999, but measure your alternator before it. If you get a bigger battery, even if it is a cheaper lead acid, make sure it is deep cycle. If it is big enough , like 80 minimum 100 AH ideal for your needs, you might not even need solar at all. YOu can get only the VSR and the battery + cables and do a test. If it is not enough, you might camp for 2-3 days in a spot, without an engine start, than you add solar.
If you look on the sites there at the premade wiring kits, you get an idea of what you need as cables, fuses, fuse boxes etc.. and buy them from you local store..
A 100 W panel with a 10 amp mppt controller will do. Like I wrote there, for any outside connections exposed to the elements use a DT series or otherwise know a Deutsche plug..
Thanks for the reply! I’d like to avoid wiring to the alternator/main battery as it adds excess complexity to my setup and I’m not super well versed in electrical wiring. If the deep cycle goes down, the worst that happens is my drinks aren’t cold and I can’t charge my laptop, although I would like to set it up as an alternate battery at some point later on.

That said, I’m looking into bigger batteries; 50ah at min. Trying to find a source that won’t inflate cost too much.

I landed on the 35ah battery because I had multiple friends advise me that a Goal Zero Yeti 400 + Solar combo would be fine for my needs, which I believe is about 30ah.

In the article I linked, the writer has a 40ah battery, but it’s lithium ion phosphate, which I’m assuming based on what you guys wrote is better equipped to run closer to zero whereas the AGM battery will only safely discharge to half? I’ll be re-examining battery choice for sure.

I’m pretty sure I still would want to keep that as an isolated system though. Thank you again for the reply!
 

kithound

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Leeloo is correct. Look, the OP mentioned cost. For what you are doing, don’t cheap out or you’ll be very disappointed on your first trip. In order for your system to work you’ll need at the very minimum a 100 watt panel, a 60 amp hour deep cycle battery, and a medium priced charge controller. That’s the minimum. That’ll work on a perfect sunshine day. If you’re looking to set up in the woods with spotty sun, or perhaps an overcast or rainy day, then you’ll be needing to double that capacity, meaning another 100 watts and 60 more amp hours of storage and at least a 20 amp controller. Oh, not to mention, the cheapo controllers are garbage. Get a good one, do your research. My system may be overbuilt as I’m running two fridges, and charging camera batteries, etc etc, but I can camp almost anywhere and have enough energy storage to last a couple of rainy days if need be. Good luck
The Renogy controller I linked comes in a 30amp version as an option on Amazon, would you consider that one good to go? And what exactly is wrong with the ones included with the solar panels?
 
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MOAK

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The Renogy controller I linked comes in a 30amp version as an option on Amazon, would you consider that one good to go? And what exactly is wrong with the ones included with the solar panels?
Yes, mine is the Renogy Wanderer @ 30 amps, which is way more than we'll ever need. A lot of guys might argue that nothing less than a PMMT controller is any good, but hey, we don't live in our vehicles full time, and it's actually less expensive to use 220 watts of panel, versus 200 watt panels and an MPPT controller as the PWM controllers are roughly 10-15% less efficient, so why spend the extra money on something we'll never use? It's kinda like home stereo systems. Why spend a ton of money on a system that will deliver something that we humans cannot hear and/or is way too big for our listening/living rooms. You certainly don't want to buy cheap, but you also don't want to waste money on a stereo system that was meant to be used in a theatre. I have about 3,000 in home stereo equipment, in 1990 dollars. I'll never need to buy speakers or amp again. Maintenance, yes, but at minimal cost. Hopefully spending a bit more now on quality overlanding gear means that I'll never have to replace any of it. (sorry for the tangent )

Over 300 watts of harvesting then yea, get the MPPTs as then it's time time to step up with the big boys. The cheap ones in the kits, or that you can get seperately lasted me about 2 trips each until they became un-programmable and virtually useless. Once I replaced them with the Renogy the difference was very noticable. Batteries came to a full charge in a couple of hours instead of 5 or 6 hours.
 
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kithound

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Yes, mine is the Renogy Wanderer @ 30 amps, which is way more than we'll ever need. A lot of guys might argue that nothing less than a PMMT controller is any good, but hey, we don't live in our vehicles full time, and it's actually less expensive to use 220 watts of panel, versus 200 watt panels and an MPPT controller as the PWM controllers are roughly 10-15% less efficient, so why spend the extra money on something we'll never use? It's kinda like home stereo systems. Why spend a ton of money on a system that will deliver something that we humans cannot hear and/or is way too big for our listening/living rooms. You certainly don't want to buy cheap, but you also don't want to waste money on a stereo system that was meant to be used in a theatre. I have about 3,000 in home stereo equipment, in 1990 dollars. I'll never need to buy speakers or amp again. Maintenance, yes, but at minimal cost. Hopefully spending a bit more now on quality overlanding gear means that I'll never have to replace any of it. (sorry for the tangent )

Over 300 watts of harvesting then yea, get the MPPTs as then it's time time to step up with the big boys. The cheap ones in the kits, or that you can get seperately lasted me about 2 trips each until they became un-programmable and virtually useless. Once I replaced them with the Renogy the difference was very noticable. Batteries came to a full charge in a couple of hours instead of 5 or 6 hours.
Yeah, the Renogy controller’s only a ~20 dollar difference so I’ll just grab that. The battery is a different story — the fridge I was eyeing looks like a 50W draw but I’m assuming it doesn’t draw that continuously, right? Only when the temperature starts to peak. And being full of already frozen stuff I can’t imagine it’d be running 24/7.

That said, I’m a bit confused by the whole “a 35ah battery is only 17ah” — I’m assuming because that battery type isn’t made to be run down to zero? Are there alternate battery types that are set up for that without diving into the really spendy categories?

Also, what about just using one of these things in lieu of the battery? Poweradd 50000mAh Charger Center Portable Generator DC/AC Power Inverter W/ USB 709445113688 | eBay
 

MOAK

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That’s correct, the amp hour rating is if you draw it down to 10.5 volts you’ll need to figure out what the average amp hour draw the refrigerator is. The more you pay for a fridge, the less amps they will draw. On average now. I rarely let mine drop much below 11.7 volts. Here’s a handy chart that I have found to be quite accurate. Depending upon brand of battery it can be difficult to revive a battery allowed to drop very much below 11 volts. I use two very simple inexpensive volt meters to keep track of everything and I use a multi-meter to check on their accuracy and voltage drops from energy source to the user. There are Lipo batteries available . The last I checked they are upwards of 800 bucks each and you have to get an entire system to charge them properly. 466BC0DD-EE99-45ED-8F1C-85C24AC34879.jpeg
 
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leeloo

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Yeah, the Renogy controller’s only a ~20 dollar difference so I’ll just grab that. The battery is a different story — the fridge I was eyeing looks like a 50W draw but I’m assuming it doesn’t draw that continuously, right? Only when the temperature starts to peak. And being full of already frozen stuff I can’t imagine it’d be running 24/7.

That said, I’m a bit confused by the whole “a 35ah battery is only 17ah” — I’m assuming because that battery type isn’t made to be run down to zero? Are there alternate battery types that are set up for that without diving into the really spendy categories?

Also, what about just using one of these things in lieu of the battery? Poweradd 50000mAh Charger Center Portable Generator DC/AC Power Inverter W/ USB 709445113688 | eBay
It is easy. Non Li batteries, the cheaper ones accessible to most people, even the deep cycle ones you can only use about half of them. If you go lower than that, then they will loose capacity, charge slower and eventually die. That means unless you go for the
very expensive Lithium packs, you will need at minimum double. So if that kit you saw was 35 amp than a normal deep cycle you need double, that means 70. But even a deep cycle, if you discharge it at 50 % non stop, will die a lot faster. Translation - if you really do not get ever more than 50 %.. it might last a few hundred cycles. What does this mean in real life .. nobody knows .. might be a year, might be 3 months.. who knows what do you do, how often you go out.. etc..
Fridges.. what you see on the spec of a fridge.. it is on ideal conditions. So you should have a bit of extra capacity and go a bit bigger. If the math so far says 70 have a little slack.. go to 80, 90 even better. You battery will last longer the less it is discharged. It is not wasted money.
You can charge it as well via cigarette plug but it will be very slow, but I guess every bit will help..
A 100 w panel should replace what you consume over night the 30 amps you say you will need in about 5 Hours.. If it is full sun, ideal conditions. More if overcast. You must remember that while you charge it, the fridge will draw power as well..
it is possible to do it on a budget, I have seen some crazy setups costing 10k, but what you want , a completely isolated system, with not alternator feed with that kind of money... it will be tight...
 
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kithound

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I managed to find a 12v 100AH Powersafe battery for 80 bucks, Manufacture Date 2016. Is there a way to ensure that this'll work/has been cared for, or am I better off buying new?
battery specs.jpg
 

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Charge it to full then let sit for an hr. Test the voltage. Let sit overnight then test the voltage again. Should be close to the same. I would then run a load test and make sure it doesnt tank right away. Not sure the specs on that battery but keep in mind most wet cell and agm batteries off-gas. Even sealed batteries may not be suitable in a rig. They do make venting kits if you trust them. On our smaller rigs that and weight are the two biggest benefits to lithium. The lithium "generators" are nice because they put the whole system in a small lightweight case. Again expensive. I used two retired indoor networking agm's which give me 160ah. The weight of the system is high enough im looking to add airbags. Once i add my camp water i have a back lean. Also i know a lot of folks sell near new batteries they pull out of their rv's because they switch to lithium right away. The more ah capacity you have the smaller the cycle rates which means longer battery life which means less $$ in the long run.

For solar there are a lot of options out there. To a big extent you get what you pay for. I would never permanently mount a flexible panel to a roof. They rarely last more than two years and often damage roofs due to heat. If you use them as portables you can get more life out of them though. Go big on the cable if you think you could ever fit more. It sucks to go through that work twice.

You mentioned not wanting to tie your engine battery to your house battery? I started with this because i never seem to stay in camp long and the alternator charges more quickly. It is a load on the alternator though. Fuses or breakers, battery isolator compatable with your batteries and some 2g cables and lugs and a run of 18g to the ignition for the switch. I also started with a converter. Just connect to battery then charge from "shore power" aka my house which reduces the alternator load. Ultimately i also added solar which does a better job of keeping the batteries topped off and healthy.

Hope this helps.
 

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A 50W panel is only going to give you a 3-4A charge. Not enough IMO. Read the specs on the panel look at the amps output not watts. 100W panel probably around 7A, still not a lot, especially with a load on your battery.