Too much or too little Solar?

[Matt71]

This is what I plan to pick up for adding solar to a Ford E150 or E250 van.
I have no idea if it is enough power or not enough power. Things I know I will use often:

27" iMac
Sony Laptop
C-Pap
Small fan
Small frig
12V Crock Pot

4 - 100W Renogy Mono Solar Panel
1- 12V/30A 400W MPPT Solar Boost 30001 Solar Charge Controller

1 - Power Bright APS600-12 Pure Sine Power Inverter (1000 watt Peak)
1 - Vmax AGM Deep Cycle 12v 125ah SLA rechargeable Battery

The iMac is probably the big power hog. At max it drains 365 Watts. That would be about 30A and would drain the battery in 4 hours right? If my solar panels charge at max capacity (33A) and the battery charge current is 30A, I should theoretically be able to run the iMac pretty consistently right? I'm pretty sure those numbers are right, but if not please correct me. I'm new to this stuff.

Anyone know what the story is on the Renogy solar panels? how do they rate?

Any advice would be helpful.

 

[skyl4rk]

Four 100W panels will put out about 25 amps. You might want to increase the charge controller rating, although you are within specifications.

You need much more in the way of battery storage. Four to eight of the batteries you listed would be a good storage amount.

The way to figure this out is to find out the amperage draw for each of the appliances, then estimate the number of hours they will be running per day to get amp-hours. Add them all up, and find a battery storage bank that will give you at least twice the amount of amp-hours as your estimated daily draw.

 

[LeeRevell]

That crock pot will kill your battery as much as the I-mac. Electric cooking is a no-no with limited battery capacity.

 

[Optimistic Paranoid]

The rule of thumb is that you want roughly 1 watt of solar panel for each amp hour of battery capacity.

With four 100 amp panels and only one 125 ah battery, I would expect your battery to be near full charge before noon, after which the panels will pretty much loaf and accomplish nothing unless you are running some real loads in the afternoon.

With only one battery, I wouldn't expect to run the imac too long after the sun goes down.

Regards
John

 

[Matt71]

This set-up is maxing out what I can afford. the Batteries are $260, so getting more of them would be tough, especially 3 more. If I added another battery and cut one of the panels, would that be a better setup?

Any recommendations for a $1200 set-up that would be better?

We can go without the crockpot.
We will also be staying at a lot of campgrounds with power, so we wouldn't use the system all of the time. In fact we're only planning to not have power about 15% of the year. Wifi is a little more of an issue though an dee might have to do a lot of work from McDonalds parking lots.

If we can build an affordable and sustainable setup we could cut a lot of those RV parks and save some cash. I'll have to crunch more numbers.

,Matt

 

[Seraphim]

This is what I plan to pick up for adding solar to a Ford E150 or E250 van.
I have no idea if it is enough power or not enough power. Things I know I will use often:

27" iMac
Sony Laptop
C-Pap
Small fan
Small frig
12V Crock Pot

4 - 100W Renogy Mono Solar Panel
1- 12V/30A 400W MPPT Solar Boost 30001 Solar Charge Controller

1 - Power Bright APS600-12 Pure Sine Power Inverter (1000 watt Peak)
1 - Vmax AGM Deep Cycle 12v 125ah SLA rechargeable Battery

The iMac is probably the big power hog. At max it drains 365 Watts. That would be about 30A and would drain the battery in 4 hours right? If my solar panels charge at max capacity (33A) and the battery charge current is 30A, I should theoretically be able to run the iMac pretty consistently right? I'm pretty sure those numbers are right, but if not please correct me. I'm new to this stuff.

Anyone know what the story is on the Renogy solar panels? how do they rate?

Any advice would be helpful.

Short answer - no.

Just installed the Renogy 400 watt kit with MPPT controller and went to Florida for several weeks. Haven't had the chance to do a complete test on the sustem because we drove each day and the alternator did the recharging work. Never got the batteries below 84% (210ah batteries) but on the day we did at 9:30 the next morning, on an overcast day with flat mounted panels the battery was pulling almost 8 amps from the panels. In 45 minutes the batteries went from 84 to 86%- then we drove off lol. Had we stayed, at that rate, four hours would have recharged the batteries ( but as the sun rose we should have gotten more amps from the panel's and a faster recharge time).

You can't run your battery down completely - it will die. Only take it down to 50%. The Renogy 400 watt panel's - under ideal condition with needy batteries - can provide about 21 amps. You'll get that rarely, I think, unless you're under clear skies with direct sunlight hitting your panel's squarely. How often will that happen, or coincide with the 15% of the time you'll need the panel's?

You'll need to put 10% more amps into the battery than you used. The panel's are not going to provide the power you need to keep your Mac running all the time.

I like the panels. They will do what we intended, but we only use about 25 amps a day. We used about 34 in the previous example, but we tried lol. Left a fan running all night. So an overcast winter day should still bring our batteries up close to 100% in 3 or 4 hours. When we're back on the road we'll try to find better skies to experiment with; then we'll do a report on the system

As is, I think you're expecting too much.

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Forgive the misplaced apostrophes on the plural word panel's - the iPad autocorrects it this way, for some reason, and I get tired of back spacing to change it...

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I'd get rid of the inverter, personally, and add another battery. We don't use 110 when boondocking. Not really necessary.

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Don't need sealed batteries, either. Go flooded initially to save dollars. Just be sure to vent them.

 

[Matt71]

I won't need the Mac running all of the time, but when I'm working on photos it's likely I'll need it on for 4 hours or more a day.

I might also have a BluRay player (30W) and projector (258W) that we might use with a pull-down projector screen, but that will depend on how easy it will be to mount it to the ceiling and be able to disconnect it easily in case we want to do a movie night for fellow campers. And we'd never use that and the Mac at the same time

 

[jimindenver]

A imac, fridge, c-pap all 120v? You need to get a handle on how much power you are looking at. Find their tags and see what the Ah draw is at 120v, times that by ten and you have the draw on your battery EVERY HOUR. What about lights? They can pull the juice if they are not LED.

So before you buy anything, figure out what you are looking at. I think it is possible you will need two batteries just to get the c-pap and fridge through the night. Forget the Imac. I have 345 Ah of batter and it would suck that dry in no time with out my solar helping.

 

[Matt71]

The Cpap is 1.25A or 3.75A at 120V depending on if we use the humidifier attachment
Laptop pulls 1.2A at 120V
We have a oscillating fan that is .3A at 120V, but we can by a smaller 12V one.
I have no idea how many Amps the iMac uses, just that its max wattage is 365 Watts
The frig has not been purchased and is not a necessity. Probably not worth the cost vs a cooler and buying ice.
Lights will be LED, but not sure what configuration we'll use.

 

[highdesertranger]

now you need to figure how long you want to run everything per day. imac is about 3amps at 120v. how far will you have to drive for ice? you must figure that cost into the use of the ice chest. remember running things though an invertor you have losses invertors range from 70-90% efficiency. highdesertranger

 

[akrvbob]

A few thoughts:

400 watts is a lot of solar and will easily do everything you want except the iMac. I'd suggest you buy a Kill-a-Watt from Amazon and find out the exact draw of the iMac. The BIGGEST question is, how many hours a day will you be using it? If you use it for 8 hours a day and it does draw at 30 amps then that's about all you get from the 400 watts. You'll have to chose between it and everything else or get more solar. Can you switch to a lower draw Mac?

The crock pot is 12 volt and only draws 9 amps, by itself it's not a big deal. It would only be a problem if you wanted to do long, multi-hour cooks. If you can plug it in while you drive, it will have zero draw on the house battery

one battery is simply not going to be enough. Better to get 300 watts and and get a 2nd battery. Best of all is getting lead acid and vent them and keep the 400 watts.

Renology is a fairly new company so they don't have a track record yet. But, they have become very popular and so far they appear to be a great value for the money.
Bob

 

[Matt71]

I did some math. Not sure if there is more that we will need, but we're looking at about 500A.
This is the current list

iMac 30A @ 4hrs = 120A
Laptop 12A @ 4hrs = 48A
cPap 12.5A @ 7hrs = 87.5A
Fan 3A @ 10hrs = 30A
BluRay Player 2.5A @ 4hrs = 10A
Projector 21.5A @ 4hrs = 86A
3 LED Reading Lights 3A @ 5hrs = 15A
ThermoElectric Cooler 4A @ 24hrs = 96A

The crockpot we would limit to using while driving.

 

[akrvbob]

It's not gonna happen. You'll need 10 golf cart batteries.

Cut it at least in half.
Bob

 

[skyl4rk]

I did some math. Not sure if there is more that we will need, but we're looking at about 500A.
This is the current list

iMac 30A @ 4hrs = 120A
Laptop 12A @ 4hrs = 48A
cPap 12.5A @ 7hrs = 87.5A
Fan 3A @ 10hrs = 30A
BluRay Player 2.5A @ 4hrs = 10A
Projector 21.5A @ 4hrs = 86A
3 LED Reading Lights 3A @ 5hrs = 15A
ThermoElectric Cooler 4A @ 24hrs = 96A

The crockpot we would limit to using while driving.

The amperage numbers that you show do not seem to be correct. They seem to be very high. Could it be that they are one tenth of the amount shown?

 

[LeeRevell]

I'd suggest losing the iMac altogether. What does it do that the laptop cannot? Projector? Why?

Just trying to understand 'needs' vs. 'wants'.

 

[jimindenver]

Thank you for listing the loads Matt. I had him times the 120v loads by ten to get their draw at 12v. It's a rough estimate and doesn't include losses from the inverter and idle draw either.

First I agree with Bob, a vented compartment and FLA batteries will get you much more bang for the buck than AGM. AGM's can also be a pain to keep charged up requiring higher end controllers, converters and chargers.

So using your original 125 Ah battery with 62.5 Ah usable you would need two for the 4 hrs on the iMac. The fridge would need two more. The cpap and fan another two, the blueray and projector another two and one more for the laptop and lights. Added all up you are close to 500 Ah a day. That would be 4 of my 169 lb 250 Ah 8-Ds, 10 of my grp 27 marine battery or 8 6 volt batteries run in pairs. you would also need 1000w of solar to keep those batteries happy and a good sized generator to push a converter strong enough to get them back up in an acceptable amount of time.

So what can be done. First off, find more efficient gear for when you are off grid. When we first got our trailer we had gear for hook ups and gear for boondocking. A nice flat screen and DVD player were replaced with a 7 inch rechargeable TV and a 9 inch rechargeable portable DVD player. The auto drip coffee maker was replaced using the stove and a cone filter. The stereo was replaced by a mp3 player with a FM tuner and battery operated speakers. We have a small thermo fridge and used it with hook ups for pop and beer. Boondocking we use a cooler and block ice if we need more space. (block ice last a lot longer) The computer I use while camping is a netbook with an extended battery that will run for 9 hours once charged. Our battery was a single grp 27 with 95 Ah/ 47 Ah usable and it lasted us 3 days even running a furnace at night.

So you can either get a utility trailer for the batteries and solar for that 15% you will be off grid or accept that off the grid you just can't support the same life style that you do on the grid. We now can do a lot more than we use to but we have a fairly large tracking solar system, extra battery and for the better part efficient equipment. The high power equipment we use such as a microwave only runs a short time and then only during the day when the sun is shining. We are still using under a 100 Ah a day and we don't have to conserve doing it.

I mentioned LED lights before and to show the difference you show 3a for the lights, with less than 3a I light our 25 ft trailer end to end with ten LEDs and run a porch light that throws light 30 strides out. Believe me, those LEDs at around $2 each are a lot less expensive than the extra battery needed to run the incandescent bulbs they replaced.

 

[ccbreder]

The thermal electric cooler is a waste of money. You will be better with an ice chest. Your first set of batteries will be a learning experience. Don't buy the most expensive. don't buy "marine" batteries. Cosco or Sam's Club have 6 volt golf cart batteries. They are true deep cycle. Hook 4 in a parallel-/-series configuration and learn battery maintenance and recharging practices.
I agree your amp list seems high for what you list.

 

[Seraphim]

Adding to Jim's comments:

In our truck camper, we continually use about .8 amps an hour - .2 is a phantom draw for all the sensors, meters, etc, and the rest is for our large propane powered fridge. That accounts for about 19 amps of our daily usage.

We use our TC, otherwise, as a hard shelled tent with extras. Propane water heater: we run it for about 10 minutes each night for hot water, which lasts us for nightly showers, dishes and wash -up in the morning. Some electrical usage for the igniter, but I've been unable to measure it so its negligible.

An LED light may run for a couple of hours in the evening, if DW wants to read a book or work a crossword puzzle. If we're working or reading on our iPads, we don't need lights. A jump start battery, which can be charged when you're hooked to shore power most of the time, charges phones and iPads. So does the car, when driving. A charge on each device lasts us several days, even with photo editing. I have a laptop with photoshop if I need advanced layering functions, but mostly all I have to do is tweak the histogram, maybe sharpness and saturation. I prefer Photogene4 on the iPad for that function. Every time I turn on my laptop near wifi, I have to wait an hour for the d$*! thing to update. So even for professional level results - unless you're shooting for large fine art prints - the iPad is more than sufficient. Uses less power.

Often we run the vent fan all night for a light breeze or in areas of heavy condensation. That can increase our daily usage from 25 amps to about 32 amps, using a low setting - depending on much lighting we use in conjunction.

Cooking on a propane stove. Mechanical igniter, no electrical usage. Coffee in a cheap French press. Boil water for coffee on stove. Have also gotten halfway decent at campfire cooking. Can actually start a fire now without lighter fluid *proud smile*.

In colder climes, the TC has a propane furnace, which we've used rarely and sparingly. A lot of quilts and snuggling does the trick. First one who has to pee flicks the thermostat on in the morning. If needed at night, we can turn the thermostat on to start the cycle, then turn it off immediately. The heater will run long enough to warm up the interior, then stop.

No need for an inverter. Hiking, biking, canoeing, reading require no electricity. With the addition of the solar panels, I'm going to add a charging station for the phones and iPads to the system. Just as a luxury.

Haven't checked the power usage on the TCs stereo. We never use it. Removed the TV antenna to make room for solar panels. We never used it. Just hot back from a three week excursions. Never used the DVD player even when we had shore power. Never used Neflix on the iPad either. Occasionally had wifi. Iphone has Internet.

But as Jim said, it's all about lifestyle. Weighing what you need with what you want. There's a lot we don't need, and found that we really didn't want them as much as we wanted to be out in the peace and quiet. Together and alone. It's easy to do without a lot of stuff we've gotten used to having. And while many things are time savers, there's a lot of satisfaction to be found taking a few more minutes doing things 'manually' and enjoying the task. Helps slow us down and teach us the value of patience and enjoying the moment.

*soap box returned to garage* lol

 

[Matt71]

Well, we'll certainly have to cut back when off Grid. Most of our time off grid will be in Yosemite, Yellowstone and Big Bend where we'll be doing a lot of hiking and nature stuff. Being able to download the thousands of photos I'll be taking onto a computer will be a necessity though. Can probably get away with fewer than 4 hours on 2 computers for that though. The rest of the days off grid are single days when we are traveling between states. I'm trying to keep our drive times under 4 hours.

There's a certain point where it'll just be cheaper to stay at pricier campgrounds outside the parks than buying a $1000+ worth of extra batteries. I just have to crunch some more numbers to find that point.

I might have to trade in the iMac for a Macbook which will use about half the power, but I really like the 27" screen on my iMac. Moving to a 21" iMac would save on power too.

HERE are the LED lights I'm looking at. I may have figured the Amps wrong on them. We also may not need 3 of them, but I like a lot of light when I'm doing stuff.

The projector is 3000lumens, so it draws a lot of power. We watch everything on it at home and have become accustomed to having a viewing area that goes floor to ceiling. I'm hoping being on the road will break us of our TV habit and it will go mostly unused.

Do you have a recommendation for a low powered Microwave?

 

[jimindenver]

Those LED lights should use around 220 Ma each.

If I were to replace our microwave I would try to find one of the small 500w cubes with the twist knob.

Extra cards for the camera would be cheaper than buying extra battery.