Good folks, i have read the past pists on solar power( 2007) and i am wondering if any has done any lately on there buses. I live in mine full time all year round and i have decided on my second build to go solar. I have noticed the huge price change in complete kits. I am looking at a 800 watt system currently and would like to hear any thoughts you may have
Thanks
One of the KEY elements in a solar system that WORKS is wiring size.Make sure the wiring comiNg down from the roof is big enough(consult a voltage drop table) and that the controller is as close to the battery as possible. Voltage drop in 12 volt wiring is critical..
I agree about the wiring size. We wanted to be able to use ground-deployed panels so we could park in the shade, and this requires a longer run of cable between the panels and the charge controller. Our solution was to run the panels in series to raise the voltage but keep the amps low, which permitted use of a long enough cable without having to use battery cables. Of course, raising the voltage requires your charge controller can handle the input, as not all controllers can use the higher input voltage.
Lots of ways to skin this cat.
Good to know, i am looking at a complete sytem that comes with everything I need.
Any suggestions on purchases?
Renogy makes some good stuff.I have 3x100w panels and the controller.
Buying complete ready-to-use systems may be easier than piecing a system together from individually-purchased parts, but usually the cost-per-watt is a lot higher, plus some of the included components are not always the best quality, e.g. non-MPPT charge controllers or no-name solar panels with thinner glass than standard. You should be looking at well below a dollar a watt for the panels, and that's for good quality UL-listed panels with sturdy frames and 3mm toughened glass. If the solar kit includes a PWM charge controller, that may indicate some overall cost-cutting that could work against you in the long run.
Also, bear in mind that most kits are not specifically made for use on curved bus roofs, so some adaptation and improvement may still be needed to make them work well on a bus. And don't worry about the cost of cables - in the big scheme of things, even the fat 4/0 cables needed for inverters and batteries are still a small proportion of the total investment in a good solar system.
John
This is where I bought my Zamp panels.
https://amsolar.com/
They have a good team, and when I had any problems they stood behind their products and took care of things immediately.
I'd also concur that you'll do much better picking and choosing the components yourself. Do your research and develop your priorities. Every installation has different requirements, and if you buy an off-the-shelf system you'll end up with compromises.
I think that a good middle ground is to work with a company like AM Solar to develop your checklist of components, and have them help you be certain that you're selecting things which will get you to your desired outcome.
You'll also have to decide what your priorities are. Will you be wanting to take advantage of long sunny days with the sun largely directly above you like you'll find in the south in the summer, or are you wanting a system that can take advantage of the few hours a day adequate sun is available at a steeper angle while traveling in the north? Are you trying to run a/c unit(s) from the solar output, or just top off your house batteries?
Lots of points to consider, each with different outcomes as you work down the decision tree.
I live in the northern bc coast where the sun doesnt spend a lot of time showing itself. So i will need something that will work in low light. The sytem will only be used to keep the house batteries charged, ( so i can run basic house appliances ). I have a 3000 watt inverter from my other bus that i will be using so on that note i will give that solar company you suggest a call and see what we come up with. Thanks for the suggestions
In order to get my feet wet I bought a single 100w solar panel and the PWM charge controller from the same company. Its on Amazon.com now for $170 with added panels $113 each It came with everything to connect it up to the batteries. I then added 2 more panels to the system. Actually I bought the system on the way to go camping and installed it at the campground. The charge controller will handle 30amps so there is plenty of capacity for a number of additional panels. I also made my own mounting brackets that I glued to the roof with 3M tape. I read somewhere that you are better off forgoing the tilting mechanisms in favor of adding another panel to offset the loss due to non-tilting.The rational was that you don't want to be on the roof of your bus lowering the panels during a windstorm.
If you want to know almost all there is about solar ,and then some, google handibob. There is a couple of hours of reading on EVERYTHING about solar.
Great. I will check that out
HandiBob is well worth reading - he may be opinionated, but his facts are correct. Another good online resource for unbiased and accurate information is Northern Arizona Wind & Sun's forum for renewable energy discussions - the folk there definitely know of what they speak! If they say do something, or don't do something, there's good reason for their recommendations: https://forum.solar-electric.com/
I'm thinking that tiltable panels will give you a significant gain considering how north you are. Flat panels, especially in winter, will do tiddly-squat when you're half way to the North Pole. It ain't rocket surgery to come up with effective tilting mounts that will also be wind-resistant - just be like Isambard Kingdom Brunel and over-engineer the heck out of everything you make! Here's some food for thought: http://www.solarpaneltilt.com/ And this tells you how much solar irradiance you'll get at your location in BC: http://www.solarelectricityhandbook.com/solar-irradiance.html
John
There were two main reasons that we went with ground deployed panels for our bus. The first was so we could park in the shade and leave the panels in the sun. The other reason is tilting the panels.
Knowing that we travel mainly in the northern states in the summer, being able to tilt the panels towards the sun is important to maximize their ability to charge the battery bank. When we have our panels on the ground, it is quite clear the amount of difference it makes.
Not only do we tilt the panels towards the sun, a few times a day we will reorient them so that they point directly at the sun. Yes, it takes lots more hands-on involvement but the difference is stunning. We'll set out the panels at 8 or 9 in the morning and start the charging. The panels will be pointing NNE. By the end of the afternoon they are pointing NNW, and we'll swing them a few times throughout the day. If we know we're going to be away from the bus all day, we'll point them due south, but on those days when we come back towards the later afternoon the charge level will drop down to 10 or 12 amps. By reorienting towards the west, we can up the charge to 25-30 amps easily for another few hours.
Not sure how much of this you'll be able to accomplish with a roof-mounted setup, but if you're going to be in the northern states be sure to do your research before installing them flat on the roof.
Again thanks for all the great input. I was looking on amazon just for the hell of it and found a kit that was rated at 950 watts, but what really got me thinking is that it came with a wind turbine as well. I never thought of doing both on the same setup. Being that i live near the ocean and it does get windy i may look into a option like that. Then i could keep the panels flat and get the benifits of the wind as well. By the way the kit was priced at 2000.00 canadian
Cheap, and not so cheap wind generators are another source of irritating noise to other campers.
Choose carefully.
On the panel front, some flat on the roof, and a mobile rig-on-a-rope tucked into the bays gives you the best of both worlds?
It all depends what you need the solar to do for you, to what degree you want to be a slave to screwing with it all when camping, how else you make or use power through the day.
Lots of variables that rarely get listed in any organized way.
Is there such a thing as "solar envy"?
Happy coaching!
Buswarrior
Wind power on a bus or a boat - the ultimate virtue signal. Makes enough noise to annoy you AND the neighbours, makes virtually no power - certainly nothing usable, PITA to mount and needs setting up every time you move.
I've done a couple of solar installations and used them. The best advice I can offer is "Don't sell your generator". Solar is a lot cheaper now than when I did ours - I thought I was lucky to get down to a buck a watt and now you should be able to easily do less than 50 cents. In northern regions the efficiency is way down, more so if you take into account any desire to park your rig in the shade. Tilting them on the roof is maybe possible but a royal PITA. Sun following on the roof is only possible in theory - its not going to happen in the real world. Some people claim to be doing ground mounted panels and turning them but if you move more than a couple times a year that's going to get old real quick. If you're traveling in the contiguous US then flat mounted roof panels could be good supplement to float charge your battery bank - for the rest of us they're pretty much an ornament. But either way, don't sell your genset.
Still looking at generators, thats a whole nother topic, going to do a lot of sound proofing in that bay
Depending on how much backup power you need for your solar system, there are several very quiet self-contained generators. Some here have experienced excellent performance and value, no need for added sound abatement.
I was looking at a honda generator setup that is 2 2000 watt that join together if needed for 4000 watt power. I am really only using the solar and generator as back up power incase of a power outage. Maybe in 5 years when i retire and travel it will be used for off grid parking. But 90 percent of the time i will be pluged into shore power.
Does your controller allow for inputs from two sources: primary- the generator (AC), secondary - battery bank (DC)?Maybe one 2k gen would be sufficient if the battery bank could take over when the draw exceeds the generator's max output.
The way i have it planned in my head it should all work together. I like the generator i am chooseing because i could either leave it as a 4000 watt unit, ad a third to make 6000 watts or remove one unit and have it in my camervan as a 2000 watt unit. Which i am also going to put a couple solar panels on.
https://www.youtube.com/watch?v=VLzXBOWFM3c Here is how I installed my solar panels. I used commercial panels bought for about $.50 / watt.
So I have 1950 watts on the roof, in practice I pull down 1200-1500 watts from the hours of 10 am to 3 pm in full sun. For a battery bank I have 6 x 12v 205 ah AGM Telecom batteries, for 14,000 kw of battery capacity. 2 Victron 100 / 50a solar chargers - 2 victron multi plus inverters.
As the summer winds down I've done some reflecting. I love my solar system, but... it's not been everything I've hoped it would be. I have plans to improve it. Here is the thing I've come to learn but never realized. When you have a big battery bank, you need a way to charge it up in the day plus meet your current energy needs. I can usually do one or another, both is hard while staying cool.
While traveling this last week we stopped at Mears Beach in Michigan, parked in the parking lot during the day, pulled in enough power to run 1 AC unit while the kids played at the beach and I worked. It was fine, but we were still sitting at 80% battery from the draw down the night before, we couldn't make up much ground.
Now here is where a generator can come in, I've made the mistake of trying to get by on a smaller 3-4kw options. It can work, but it didn't for me. I tried both a 4kw Onan BFA and a predator 3500 from Harbor Freight. I think both would work fine, but not when you run them exclusively at their amp limits. I just this week upgraded to a 7kw Onan, it just fits in the MCI ac condenser bay, it seems to be very happy running 35 amps all day long.
I'm all over the place here, but I feel like I'm trying to talk to myself 2 years ago. If you don't need or want to run AC from solar / battery, 800 watts might work just fine, but don't plan for more than 600 watts for 4-6 hours a day. I have 2 more panels to bring my total capacity to 2600 watts, hopefully getting 1600 - 1800 for 4-6 hours a day. I think that will reduce generator run time while still staying cool.
Anyway, I think solar is a great way to go, but you'll still need some genny time. Also make sure to have roof vents, that's another issue, I don't yet.
Good report. Too many solar enthusiasts want to run everything off them. Reefer, ac, and enough left over to supply the nearest city. I think they are fine for battery charging and refer and small fans, but it starts getting complicated when you want do do cooling or heating, especially with any sunlight issues and limit to roof space. Great for western US, but here in the east, there are a lot of cloudy days reducing potential output. Maybe a pull behind trailer with a folding out panel array would be a consideration.
Some solar on a motorhome is a great addition to the electrical system. However, it is not as good as some people dream it is. I have 700 watts on the roof and 8 6 volt batteries. It helps a lot when the sun shines high and bright. But if it is cloudy, or winter up North, or in the shade (you don't always have a choice of where to park), it doesn't do s..t. So, as has been mentioned above, you need a generator, 6 or 8 kw minimum.
JC
All good things i am reading. The plan for the bus is 3 a/c units and 4 maxx air on the roof. Heating will be done with the a/c and baseboard heaters. The solar and generator are backup units incase power goes out. I need to run at least one of the a/c or the fans in the summer, and if a winter power outage happens at least the mid bus baseboard heaters. I was thinking of just getting one large generator but the place to put it is the problem since i am keeping the factory airconditioner. Just removing the upper compartment a/c from the bus. Appreciate all the comments on the subject.
Thanks
The trick is in the blending. no single way is going to work well alone.
And any discussion about these "power acquisition" strategies cannot help but be disjointed blurbs...!
Batteries and Solar are tough ways to do the heavy lifting of heating and cooling, there's a lot of energy needed for HVAC purposes.
A generator or a power pole are really good at heavy lifting.
However, a generator is not a good use for topping off batteries. Lots of batteries have been murdered by busnuts who kept them perpetually discharged because they didn't ever get them back to 100%. Run time on the generator to accomplish this is very long, relatively speaking.
Modern house refrigerators are using very little power compared to only a few years ago, so a new house refrigerator running via an inverter off the batteries is a lot more viable today, than it was a shorter time ago. If you haven't, go look at the labels on new refrigerators, a couple of amps at most for many of them!
So how big do you go with solar? Well, how about size the solar to reasonably recover an overnight of refrigerator running and those couple of lights, CPAP etc.
If you are camping in pleasant temps, that's all you really consume in power.
If you run the generator for anything, it will be putting power back into the batteries while you cook, dry hair, HVAC, etc.
The generator doesn't have to be run to just charge batteries, the solar panels can "put the polish" onto the bank, and get it to 100% pretty much every day.
Solar is also VERY good for keeping the batteries healthy during times of storage.
Those couple of solar panels and decent charge controller will likely pay you back in the battery budget, as your batteries should live a longer and healthier life.
Don't aim for everything, aim for something, several ways?
happy coaching!
buswarrior
Sean,
Thanks for the introspective and insightful update on your solar experience and system design. Solar is still on my list, just not near the top. I'm considering lithium batteries, more as prices keep generally trending lower.
Using lithium for storing for solar generated energy in a bus conversion offers enough benefits to be considered.
Lithium charges faster.1C is generally a good general max charge rate for LiFePo4. Using 5 hours daytime sun as the primary energy collection period, this battery can be charged up.
Lithium has greater capacity and depth of discharge. With increased usable watts, fewer batteries are required, weigh less, and battery bank takes less space.
Lithium should last longer with 1000 charge cycles.
Lithium is more costly. This battery is 12v x 100ah, about 1200 watts capacity, usable 800 watts (2/3 DOD). Four of them makes a battery pack with 24v x 200ah, 4800w max/3200w usable. This seems sufficient for running everything except the AC. Something like this runs around $3000.
I'm not making the argument that solar can do it all, all the time, but it seems like running the AC via the generator, even a smaller one, bridges the gap to keep the battery bank charged up or at least enough to supply energy for the bus.
https://www.batteryspace.com/lifepo4-rechargeable-battery-12-8v-100ah-1269-7wh-100a-rate-with-bluetooth-option---un38-3-passed.aspx
Features | Battery | Replace Lead Acid Battery with lighter weight and Higher Capacity |
| Voltage | Nominal Voltage: 12.8V;
Charge Voltage: 14.40±0.25V
Discharge end of Voltage: 11V±0.1V (2.75V/cell)
Overdischarge protection voltage :8.8V±0.1V (2.2V/cell) |
| Capacity | Typical: 100Ah; Minimum: 96.2Ah @0.2C discharge |
| Charge Current | Standard: 20A
Maximum: 99.2A |
| Charge Time | Standard: 5-7 hrs
Maximum: 2-3 hrs |
| Discharge Current | Standard: 20A
Maximum Continues: 100A
Maximum Surge: 150A |
| Internal Resistance | <20mΩ; AC Impedance 1KHz |
| Weight | Net Weight: 33 LB (15Kg); Shipping Weight: 35LB (16Kg) |
| Temperature | Charge: 0 to 40°C
Discharge: -20 to 60°C
Storage: 1 month: -20 to 60°C; 3 month: -20 to 45°C; 1 Year: -20 to 20°C |
| Dimension |
- With Connector 13" x 6.8" x 8.75" (340mm x 173mm x 222mm)
- Without Connector 13" 6.8" x 8.25" (340mm x 173mm x 210mm)
|
| Terminal | Copper Pillar, DiaxH : 19x30mm |
| Charger Option | You can purchase 12.8V 15A LiFePO4 charger (https://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=7648) for this battery with CAN Communication switch overrided 'ON' |
| Notes |
- Can be connected in series upto 4S and unlimited in parallel
- Must use LiFePO4 charger to charge each module. Do not use Lead Acid charger to charge this battery.
- There are some milliampere consumption due to digitlal output, please maintenance it on time base on its remaining capacity to prevent it from over-discharge.
- This battery must be shipped by Class 9 package, and there is extra handling fee, please add handling fee into shopping cart
- Ship with US address: handling (https://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4744)fee
- Ship to Canada address: Please choose UPS Standard (https://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=5827)
|
What do you do with the lithium batteries in the cold weather?
My wet cell batteries stay put all year - I just keep them plugged in and charged. This allows for us to use the bus and camp as long into the winter fall as we dare. Our wet bay is heated to keep the water flowing, but our battery bank is not.
From the information you posted the lithium don't seem to like the cold (assuming my C to F translation is accurate). Would they need to be pulled when the temps gets below freezing? Or, are there setups which include heaters just for the batteries?
Don't get me wrong, I don't regret the solar one bit, I still plan to expand it. I've not known rving without batteries and solar. I don't think I'd like having to run a genny all the time like I've seen many other campers in no hookups campsites.
On batteries. I forget if I mentioned, but I went to some telecom cells this year. They are still lead acid technology, but AGM cells handle deeper discharges and faster charge acceptance. They also seem to have better cold weather performance than typical flooded lead acid. I found these for $160/ea hard to beat that.
I went with these batteries in part because of the cold weather worries of lithium. Now from what I gather the issue with freeing temps and lithium is more on the charge side than discharge side. As luck would have it, if you discharge them they heat up. So, if I had a good sized lithium bank, I could run the electric hot water heater to draw enough amps to heat them up above freezing. Then I could charge them which would continue to warm them. I suspect if they are getting cycled daily, it would be difficult to get them below freezing in even below 0 temps inside a bay with just a thermal blanket for insulation.
One downside to mysetup and an upside to lithium is not needing to be fully charged, my AGM cells need a full charge every 2-3 days, that can be hard if it's cloudy. Now I usually hit 28v at some point, but they really need to see that for 2-3 hours or more for a full charge.
That said even at $650 per 100ah @12v I can't justify lithium, when I'm buying 200ah @12v for $150. I know AGMs should only be used to 50%, but even at that, it's less than 1/2 the cost... aaaand in a pinch I can go past 50% without much damage if I recharge shortly after. I've done a 90% capacity test with no measurable loss of capacity.
Keeping Li batteries in the recommended operating range is addressed by electric motor vehicle designers. Seems like you need to keep the batteries in a heated compartment. It would not take much to keep it warm given the small volume of the storage compartment. In my case, the bus is fully equipped for cold weather. Electric heating wire on all externally exposed piping, hot water radiators in all bays connected to webasto, and engine block heater.
Lithium sound like the perfect solution...in probably 7 to 15 years. Too expensive, too fussy as to recharging and temps in our situation. As well as they work in compact drills, phones, and other items, they are very impressive. Maybe sooner. Look how far solar has come in a few years. The way the voltage output is climbing in these larger hand held items, shouldn't be too long till they are up to 120 volt. When that time comes, I wonder how many it would take to run one rooftop air conditioner. Just line up as many batteries with their own chargers as needed, wire them to output while still in their respective chargers, and cut output and turn chargers on to recharge. I know that is an elaborate way to do it, but would be an easier way to get started.
The best return on investment today is still the good old flooded acid battery. I don't see the advantage in spending any more money on anything else.
JC
Quote from: lostagain on August 24, 2019, 06:21:41 AM
The best return on investment today is still the good old flooded acid battery. I don't see the advantage in spending any more money on anything else.
Absolutely true with one big caveat:
As long as you do the routine maintenance. If you're not going to do the maintenance and do it religiously then spend the money for AGMs
Everyone lists the advantages and what they'll do...
What about the dangers of lithium in the hands of goofs like us?
If a busnut can't take care of a flooded lead acid battery, murdering them via a number of methods...
How much danger is the same dolt's neighbours in, parked alongside in the campground, when it all goes wrong?
Overcharging, undercharging, short-circuiting, overloading, dropping them, ignoring physical changes in their apearance, miswiring a bank of them, etc...
Every crazy thing a busnut has done to lead-acid, what happens to lithium with the same disregard and ignorance?
Why do my firefighter friends not like electric cars at accident scenes?
Ain't no free lunch, and the fact nobody is talking about the specific safety issues with lithium has me very suspicious.
Happy coaching!
Buswarrior
The fire danger of lithium is mostly with the volatile cells Telsa uses, Lithium Iron Phosphate cells are safe and don't explode like the 18650 cells Tesla uses.
But yeah, I'm shorting the market on lithium battery prices.