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Inverter/charger | 8 comments (8 topical, editorial)

Re: Inverter/charger (3.00 / 0) (#6)
by arbela47000 on Sun Sep 28th, 2008 at 06:55:07 PM MST
(User Info)

Well, I wasn't too concerned about the sale price expiring; I won't be building this system for about 3 years. I plan to put in Uni-solar shingles or laminate strips for a total of around 3 kW. If I have an inexpensive (self-made) turbine or several that can take up some of the load, I can likely size down my solar generation capacity and save a bit of money on the production side of things. I plan to use a powerful inverter so that I have the surge and operating capacity to run a walk-in cooler. I plan to run with about 150 kW of battery storage for a couple of reasons: 1)the walk-in cooler; 2)the climate where I'll be moving is one I know pretty well, and it can get pretty cloudy there for extended periods. The longest cloudy/rainy spell I saw up there was about 28 days. I figure a lot of battery power will be needed to last through that, although wind power would help alleviate some of that concern.

Here are the things I don't know about my system:

I don't have a specific site picked out, although I have my eye on one or two. I may find a fantastic micro-hydropower site, in which case all of this concern about wind, panels and batteries will be a moot point.
I don't know if I'll be grid-tied or not. If so, I'll cut down on batteries and save a good deal of money. Additionally, I'll probably make a whole bunch of devices to produce power and sell it back onto the grid. If not, I'll need to make a dummy load (like a pond heater) to take up the excess load when the batteries are full.
I don't know what charge controller would be best, so any suggestions would be welcome. I'll probably run either a 24 or 48V system, if that helps. What exactly does maximum power point tracking mean, and how much better (or worse) is that than non-MPPT?

I don't plan to do anything without plenty of research and conversations with people (hence why I've signed up for this site three years before I'll need to use the information). I may build some proof-of-concept models to make sure that I understand everything, but the real deal is still in the future.

Sorry this was so long, but you did ask for details. :) Thanks in advance for any advice/thoughts you care to share.

[ Parent ]

Re: Inverter/charger (3.00 / 0) (#7)
by scottsAI (user name at eml dot cc) on Sun Sep 28th, 2008 at 08:12:11 PM MST
(User Info)

Arbela47000,
I would rate that answer as just right!

Cool.
I designed a 8x8 foot freezer using parts from a chest freezer.
Have not built it, someone else was interested.
Wife doesn't like my projects, so have stayed away from building much beyond a whole house UPS to keep essentials going for couple days.

MPPT is maximum power point transfer.
Electronics to match a solar panels output to a battery.
Solar panes are rated at some ideal voltage and current to make rating of panel.
Example for a 34 watt panels is17v at 2 amps. (easy numbers)
If connected directly to 12v battery, you get 13x2 or 26w of usable power.
Much less than the rating of the solar panel.
MPPT controller will boost usable power up to maybe 32watts.
Depending on you planetary location the benefits of MPPT can vary just like a tracker.
Here in MI, claim is around 25% boost in power using MPPT and 29% tracking.
Both if done DIY are cost effective, cost determines whether its worth doing.

Have fun,
Scott.

[ Parent ]

Re: Inverter/charger (3.00 / 0) (#8)
by arbela47000 on Mon Sep 29th, 2008 at 04:32:14 AM MST
(User Info)

Okay, so I did the math to figure out what size charge controller I needed, and then noticed that the only MPPT charge controllers I could find that would run a 48VDC battery system were the OutBack ones. Only problem is that the spec sheet for those controllers says: "Consult factory for approved hydro/wind turbines." Do you know of any problems that might arise with turbines that would fry a controller? I tried to find a post that talked about such things, but came up with nothing.

If I would be better served by posting this question in the wind section, I'll ask over there instead. Thanks.

[ Parent ]

Inverter/charger | 8 comments (8 topical, 0 editorial)

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