Tell me what I need!

[SternWake]

MSW inverters are fine for most things, but if you can afford true/pure sine wave inverters, then you need not worry about those few things that are not compatible.

No law against having one of each instead of one huge honker either.

Splitting a battery bank to better manage charging has its advantages like a higher amperage which meets can feed a higher bulk rate, and also for equalizing the batteries at voltages in the mid to upper 15v range. These higher voltages should not be applied when there are electronics still hooked to the charging batteries as it can be near or above the danger zone.

It's basically what i do, but I only have 2 batteries total, and one I basically keep full all the time for engine starting duties, but I can choose either battery for either duty at the turn of a large switch, but I need three switches for complete manual control.

 

[kyonu]

so I did some testing with the Kill-a-Watt device, and got results far lower than I was expecting! So far here's what I have:

For my entire work station when fully functional: 100 watts, 2.5 amps. Should go down when I get LED monitors.
For the workstation when printing (less than a minute): 400 PEAK. This happened for about 5 seconds and went down. 4 amps peak. Again this is just when printing, which I do rarely.

Laptops: 12.5w when charged, 45w when charging (per laptop, out of 2 laptops)

LED TV 50": 130 watts when idle, muted or full on.

Blender (which will be used regularly): 200 watts at highest speed. Will use less than 10 minutes per day.

Things I have not tested: Omega 6000 Juicer (rarely used), toaster (rarely used), dehydrator (rarely used), humidifier (will probably get rid of this one), and vacuum which I will test when we use it.

With that in mind, do you need more information or is this good? I think combined amps will be well under 20.

 

[akrvbob]

You could probably get by with a single 250 watt panel and a pair of golf carts. Just buy a controller big enough to add a second. Try that out and see if it's enough. It probably will be, but if it's not add a second panel and another pair of golf carts it almost certainly will be.

You want you batteries to be very close in age and condition, so you will want to add the second pair as soon as possible after the first pair, or set up a completely different system.
Bob

 

[Technomadia]

@Optimistic: I have read technomadia's stuff. They're popular and know their stuff, I just don't really follow them. They are tech guru's but can't even get their live stream video's above 240p... that confuses me. Anyways, their article is also 3 years old. I was looking for the new lithium batteries (which unfortunately are more pricey...) But I decided I think I will do AGM for now, and then upgrade as I go so I understand my power requirements more.

Yes, our original research was 3 years ago, but we've kept the page updated with status reports since, and kept in touch with key players in the industry. There's really not too much new that has happened with LFP anyway - except prices have gone down and capacity up. The cells we went with are now higher capacity for the same price, and we're intrigued by the offerings of Balquon, which are much less. If you have leads on 'new' lithium battery options, would love to add them to our research list.

Sorry about the lithium video.. which is the one I presume you're referring to in your complaint about us. It was amazing we could get a connection at all for that one from the location we were at with a live audience assembled - and we almost didn't stream it at all. Most of our webcasts are broadcast in HD.. but it all really depends on what sort of internet connection we can get the day we broadcast, and then how well UStream imports to YouTube. That day, just seemed all towers coming into our remote location went down, despite having done extensive bandwidth testing just an hour before the broadcast. Tis life on the road. One day, when we have that fanciful free time thing.. we might re do the LFP video update in higher quality. For now, it is what it is.. not like we have a vested interest in this stuff after all

 

[VanLifeCrisis]

you might opt for a smaller led tv too..50" lol. nothing like watching the wall after dinner

 

[kyonu]

@Technomadia: Thanks for the reply! I didn't mean to sound harsh if I did, just stating what I noticed. Thanks for the info on the batteries though, but for right now I think I will stick to AGM for the cost savings. They may not last as long, but by the time they are dead, LiFePO4 will either be just as cheap or outdated (based on the current research time frame I'm noticing...)

@Bob: I was thinking about that. I will probably start off with two 250's and keep them outside so I can rotate them throughout the day; might be easier than just mounting them up top so I can get more sunlight out of 'em. As such, I will probably get two separate battery banks at the same time.

Now I just need to put together the list of things I need! So as above, I'll need to add together the remaining appliances and see where I sit!

@Dazar: Exactly. 8)

 

[akrvbob]

I have friends who shuffle their panels in and out. The key would be how often you move. If you have a toad and sit for 2 weeks, no big deal. If you drive every few days, I think it would get very old, very fast. You'd be tempted to leave them at home and maybe come home one day to them being gone.

I'm too lazy to do it. Of course you could try it and if it doesn't work, mount them later, no harm done.

I forget your rig, but if you have a van it is very easy to set the panels up to tilt and fairly easy to raise and lower them. With an RV it's harder, but you probably have a toad and sit longer so it's actually easier. I have a friend with a single 250 watt panel and he raises it whenever he's camped and moves the van twice a day to face south-southeast and south-southwest. You can't practicably do better than that. In the summer the sun is so high moving it or tilting it is almost no value.
Bob

 

[SternWake]

Before I got Solar i was designing a system in my mind to be able to tilt and track the sun, and When I built my corner mounts this was also a prime consideration.

Now it is 7 years later. How may times have I tilted this panel so that I can harvest all I can? Because I absolutely need to? Perhaps a half dozen times. Total, though I can only specifically remember doing it twice.

Now I tilt it just to clean below it. When My needs increased, I added more solar.

Certainly easier than tilting the panel I have or repositioning the van to follow the sun.

If the roof space is available, cram as many panels up there as possible and not worry so much about Sun tracking. Sure one can harvest more but tracking is a Pain in the arse. it gets old quick, and if set up to face morning sun, then you are committed to moving it twice more through out the sun's arc. If you forget, or do not, then harvest will be less than a panel flat mounted.

Automatic tracking devices are complex. Just get more wattage and not worry about harvesting every single watt through tracking.

 

[kyonu]

@Bob: I'll be getting a smaller RV, specifically a Safari Trek, toward the end of the year. So it'll be a bit harder. I might need to find a way to create a rotational mount underneath the panels on the roof, plus a small lever to lift them. Shouldn't be *that* hard, right? ...right?

@Stern: You're right. I think at first I will get a rotational panel in order to get as much sun as I can, and then slowly add more onto it.

 

[akrvbob]

I agree 100% with sternwake. My first panel had tilting mounts but I never bothered with them. I've added 3 panels since then and none of them tilt. 1000 Times easier to just get another panel or be more conservative on use.

Honestly, if you have 500 watts I think you will have all you could need except in periods of clouds/rain, and probably enough even then. That is a LOT of solar power!

If you are going to change rigs, I'd wait to mount them also. It's not hard to tilt them, except you have to climb up on the roof of the RV. It's all a matter of how often you have to do it. Once a month, no problem. Every few days, problem.

You can buy electric tilts systems. They are expensive!
Bob

 

[highdesertranger]

question. what type of rv has no propane? in the op kyonu said they were going to buy a rv but no propane. induction cook top? in a rv? what's the electrical draw on that? what about the water heater and interior heater? are you going to remove all of this? or have a rv custom made, to be electric only? I see most of the conversation to be on computers and tv's . what about everything else. higdesertranger

 

[kyonu]

I said I'd prefer not to use Propane, but then later said I would use it until I didn't need it. That still stands currently.

Also, induction cooktops take a lot less than normal cooktops and are more efficient which equals faster cooking, but the Amp draw is still the same and will still drain batteries quickly regardless.

 

[Zil]

Glenn has a inductive stove in his homebuilt. He says it isn't for every one. http://www.tosimplify.net/

 

[kyonu]

I've used on before, and I think they're remarkable. Albeit you need proper pans, I would still use the eff outta it.

 

[akrvbob]

I have a friend who ordered a Sportsmobile (they only build vans to order) without a propane system. Bug bucks!!
Bob

 

[kyonu]

Okay So I heard back from Zolargus finally, the company that sells panels on a solar tracker stand (very basic and simple system that looks good) and they quoted me $1000 for the 100w panel and the solar tracking stand... For some reason, I don't see it being worth that price.

Here it is in action:


Here is the mount for the 500w in action:


Note the 500w only comes with the mount and not the panel like the 100w system. 500 watt system looks too big to carry around in an RV anyways. I was thinking of maybe finding some flat-rollable panels that would equal the combined weight of the 100w panel on the mount and get more use out of it that way. If $1000 is worth it. It might be for just one system perhaps...

 

[akrvbob]

If you size your system properly, there is no need for that at all. That's money flushed down the toilet.
Bob

 

[Prisoner Of Knowledge]

I have to hand it to Bob...he's really up on his stuff! I learn so much...

 

[TucsonAZ]

A few bullet points...

1) Avoid tracking, it made sense at $7 plus dollars a watt, it no longer does with solar down to $0.70 a watt.
2) Avoid induction anything, heating, cooking, it's a power hog and not functional on solar. Have you seen things like the Nissan thermal cookers? I hate propane myself but sadly it just has the other options beat. A crock pot on solar is just a no go unless you just want to run a crock pot.
3) The fridge on propane will be a resource hog as well, they don't work well and use a lot of propane, when run on electric they use 3x what a normal (and larger) home unit would use. I would look into a chest freezer conversion, they work well and mine runs on 10w/hour.

I'm not sure if it was talked about earlier but you're asking for a lot of power from solar, reduce usage in all areas first, mandatory as there's only so much roof space for panels and weight you can carry in batteries. Which brings me to:

4) You don't want to discharge your batteries under 50% so if you're using 7kw you're going to need a 14kw bank which is let's call it 1,200 amp hours, not "undoable" but a lot of weight and battery.
5) You want to avoid parallel connections overall, two battery banks is okay but beyond that becomes troublesome. So relating to #4 you would potentially want something like six of the Trojan L16RE batteries which would give you a 13kw battery bank at 12v. Solar to charge this would be in the area of 2kw which is a lot of roof space.

 

[kyonu]

Tuscan:

As in my previous posts, I have been writing down my wattage usage. I haven't had a chance to test out everything yet, but so far I'm not above 200w per hour on average. This would only be for 8 hours, then that wattage drops to below 100 watts, up to 220 watts (for 1.5 hours max).

Doing the math of what I currently have, I will need 8 hours of 200 watts, plus say 400 for a quick 10-minute coffee, that's only 2000 watts that I need for an 8 hour period.

After that, I will need at minimum 100 watts for the next 8 hours, so 800 watts, plus 120 watts for up to 1.5 hours, so 180 more watts, which comes out to 980. Giving myself an extra 300 watts to use for igniting propane, running a Blender and possibly a juicer for a small period of time, that brings me to 1280 watts. Combined with above, that's only 3280 watts for the average day, which is less than half of my original estimate.

My main problem is the refrigerator. If need be, I will try finding the smallest-wattage fridge I can get, and thermal-wrap the crap out of it so it retains its cold on the inside so power has to run less. But I will be living in a Class A RV, not a van, so I will need a full size unit. I will also have another person living with me in there, so a small chest freezer without a microwave for 2 people is not doable. (Yes that's right, no microwave. Haven't used one in 2 years, and not about to start again!)

Lights in the unit, say running 16 hours a day at 20 to 50 watts, that's max 800, so still around 4000 watts a day without the fridge, or less than if I only have one set on at a time. (chances are the bedroom and living room light will be on most of the time, not all, so it should be far less.)

So right now I'm looking for around 8000 watt hours per day in batteries, minus the fridge in which I still don't know how to calculate.


EDIT: Also, about the tracking system, chances are I won't do it, and if I need more juice from the solar I can just rotate it manually until I can get more units. I have a lot of room on top of the RV!