Aquaponic Gardening

A Community and Forum For Aquaponic Gardeners

I just realized I am being foolish.  I don't have a backup generator, inverter, auto turn on or batteries.  What do I need to know and what would be the best products for a smaller setup?

Views: 560

Reply to This

Replies to This Discussion

What you need is a DC Circuit Breaker...

They only cost $15-40.00 (depending on where you get them)...

GFCI are ground interrupt tripping devices - not circuit breakers.  So a GFCI is not really giving you real circuit protection.  But in the event of a substantial over current event some drain imbalance (usually caused by an undersized ground wire for the current draw) will cause the GFCI to trip.

..

GFCIs are used out doors because when you get electrocuted you cause a ground current loop which trips the GFCI (which - you guessed it, is tripped by a current through the ground lead) disconnects power to minimize the effects of being electrocuted.  And, hopefully preventing you from being killed.

...

If you want a fool proof back up -

..

Use a deep cycle battery, with an always on Inverter to run your water circulation pumps and air pumps (if they are AC pumps).  Then use a battery charger to trickle charge the battery and supply current for the Inverter.  There is no cut-in cycle time, and no power gap when the power goes out before the new power kicks in.  Using this set up ill also extend the life of any conytrollers, computer based controllers and pumps powwered by the "Hillbilly UPS".

..

Commercial power has over 190 power events per hour, 40% are over voltage, and 60% are under voltage.  This is a "National Average" so your neck of the woods could be worse, or could be better.  Here in Phoenix, Arizona we average over 300 per hour.  UPS for computers (and even my wide screen TV) are a must.  These power events radically shorten computer hard drive life, and god only knows what it will do to that 60" HD TV....

...

We used this type of hillbilly UPS for a web hosting start up for eight years.  Now we have gotten big enough to buy a $39,000 commercial UPS rated at 50KW - power back up has never had it so good.  But the hillbilly UPS is an excellent solution for your back up needs.

...

Dave

Phoenix, AZ

Just make sure the Charger can handle keeping the battery charged while also supplying the current to run the things plugged into the inverter.  Make sure the inverter is a good one (I've had a few of them give up on me and teach me to spend a bit more money for a good one.) Make sure the inverter has plenty of capacity to handle what you will be plugging into it and keep in mind when pumps start up they need quiet a spike of juice so the inverter needs to be plenty oversize.

Cheap Inverters vs Expensive Inverters...

...

Normally a cheap Inverter will suffice for most applications.  The expensive ones have more symetrical sine wave replication (looks more like a sine wave than a square wave) and more bells and whistles (more bells and whistles are not all they are cracked up to be - I tend to believe them to be a waste of money).

The problems that people have with Inverters is a lack of understanding about sizing an Inverter.

If you have a 400 Watt Nominal Load - you don't buy a 400 watt (or a 600 Watt) Inverter - You buy an 800Watt or a 1,000 Watt Inverter (Better Yet a 1,200 Watt Inverter).

...

Inverters also tend to draw 10%-20% of rated power at rest (No Load, ie:  Pump/Compressor Motor off).  So you must figure this in with the battery load calculations.

...

Point:  Battery's - Your battery bank should be rated at least four times your maximum load.  If you need 100 Amp Hrs in a 24-hour period, you should use a 460-540AmpHr Battery (not a 540 Cold Cranking amp battery - this is only an 80 Amp Hour Battery).  Naturally, you want a deep cycle battery.  The reason for 4X load capacity requirement is to keep your battery discharge cycle between 25-45% of rated capacity (This extends battery life significantly).

..

Point about Solar Arrays:  Solar arrays are basically 80-85 Watts (a 170 Watt array is 170 watts at X ampres with a load voltage capacity of 19Volts or 21 Volts (You will be using a 13.8 Volt system - so you will only get about 80-85 Watts out of the panel, 115 Watts if you are really efficient at laying out all the array to charge controller wiring ).  When you design the solar array take this into consideration.

..

Also:  Solar panels will not be as efficient as they say they are - so de rate your 7.8 Amp panel to about 5.5 Amps (trust me it will not produce 7.8 Amps, unless you put it on the moon).  Also remember to size the array (collection of panels to produce your desired load x 2.5 over the minimum daylight hours for your locality) so that you have enough reserve for those rainy/stormy dark thundercloud days.  Your array must be able to bring the battery bank charge back to 100% on the next full sunlight days.

..

Now a note about real practice:  I have worked on solar installations that were working adequately with an array designed to produce exactly 100% of rated power for any given day, but the battery bank has always been more than 5X load capacity.  In reality, you size the array for the shortest sunlight day period (and since all the other days of the year are longer, you generally do not have any significant problems, but then you can never draw "any" extra power, and there is no wiggle room at all... your choice, be cheap or thrifty and hope for the best, or sit nice and cozy knowing the system has the capacity to do the job)...

...

Cheap inverters do not always handle Inductive loads (Motors, etc) - but it doesn't mean you cannot use them with motors.  A few .01 and .1 micro farad caps rated at 450V across the AC leads to the motors tied to chassis ground should eliminate a majority of those back EMF issues, if the caps cause undue loading, use 1 watt 160 ohm resistors in-line with the caps.  Cheap inverters tend to do screwy things with their stepped square waves, and tend to develop negative voltage spikes, which cause massive current spikes when motors turn on/off.  This is caused by the impedance loading effects of the motor windings when the electrical field collapse occurs (the voltage in the inductive field folds over as it degenerates).  The opposite effect happens on power up which causes a spike in current and momentary drop in input voltage (this raises hell with the switching transistors in the inverter if the inverter is anywhere near it maximum rated capacity).

...

Just a few points for those contemplating a solar installation...

..

Incidentally my Solar experience base includes several highly successful projects.

A solar Powered Radio Station in Alaska

A solar Powered Village Pump System in Senegal, West Africa

A solar Greenhouse in Tennessee

A solar powered Stable in Tennessee

A solar powered House in Georgia

A solar House and 3-Car Garage in Arizona

Numerous Solar Powered Microwave mountain top repeaters in various parts of the world.

A solar powered Meterologic Network across  Greenland, Northern Canada and Alaska

A solar powered Dive Camp on Great Inagua Island, Bahammas

....

Want an indepth Solar Power hand book - Adi Pfeifer (New Mexico), The Complete Solar Handbook (2nd or 3rd Edition).  Adi is the geru and go-to guy on solar power.  You can find his books in almost any decent public library.

...

Dave

Phoenix, AZ

Thanks Dave,  Lots of good info there.

 

One note in choosing inverters I think one needs to also think about where the inverter is living.  Mine is in the garage and two died, they were definitely rated big enough (I was only running a 60 watt item with the 400 watt inverter) but I think the heat was killing the inverters in summer.  So after the second one died I did some searching for an inverter that actually listed the acceptable operation temperatures.  That one has been running for longer than the other two put together.

Florida really isn't that hot - but,,,

Being in the garage without circulating air could definately be a problem...

... I have run "cheapie" Harbor Freight Inverters here in Arizona for the past twelve years....

..

I have noticed that they do not last long in direct sun, and without a circulating fan (the one that comes with the inverter is like getting tooth picks as a support shim for your coffee table - stupid and ineffective.... What were they thinking?  Oh, yea, they just want to sell cheap inverters...).

..

I have unlimited access to Industrial surplus .. Silly things like battery banks, Super Sized UPSs, Silicon Ingot saws (great if you want to grow and make your own solar cells), Tractors, Chemical processing, Water Filtration (all levels from 1,200 GPHr RO tio Full Fledged Water Treatment plant equipment.

..

I like building things, and not dinky things... Things like Greenhouse (like the Biosphere2 types http://www.b2science.org

... ), Ethanol Plants, Biodiesel Plants (large & Small), Aquaponics Systems (small to large scale)....  It helps to have reliable and resourcefull sources where you can buy $100K of equipment fdor as little as $10K or less...

.....

Dave

Phoenix, AZ

Yea, FL isn't that crazy hot but about all I can figure is the inverters I was using from Northern Tool were just not meant for continuous use in 90+F  The first one the little fan quit and I got it replaced as it was still under warranty then the second one died completely and I figured it was a sign that I needed something that could survive up to at least 100 F.

I've learned to read the labels of certain things, some super cheapy inverters have say things like "continuous use 100 watts for less than 20 minutes at a time."  Duh, I don't think 20 minutes at a a time with at least a half hour to cool off counts as continuous use.  But anyway.

 

We have a few surplus places around here.  Skycraft is dangerous, wander in for a few minutes and spend hours looking through the stuff.

100 watt Northern Tool Inverters are actually 40 watt Inverters (which means you can actually drive a 25-40 Watt load with them.  Any pump rated at say 60-Watts would require a 400W + Inverter.  The start stop EMF would kill anything less....

..

But I see your point... There's Cheap, and then there's cheap....

..

Dave

Phoenix

Oh no I wasn't using the 100 watt from Northern Tool  (I was just quoting something I read on a package of something really cheap from somewhere.)  Now that was cheap.

 

I believe the Northern tool inverter I did get and replace was probably the 400 or 600 Watt and I would have expected it to be able to handle a little 58 watt air pump.  Oh well.

Reply to Discussion

RSS

© 2019   Created by Sylvia Bernstein.   Powered by

Badges  |  Report an Issue  |  Terms of Service