Tom M's posts

Posted by Tom M on Sep 28, 2015 01:01 am

#1 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: newbie, here! had an oddly low state of charge
Well i feel i answered you question several times as well as referred you to the manual.  The controller requires a pv input of 12 or 24 volts, not just some random voltage which is why most pv panels come in 12, 24, 48 volts DC. If you reread my fourth post and look at the ratings on your panels, you will see that the panels operate in a range of voltages, from V oc to nominal rating. It is when these higher voltages are reached and added that it may be possible to near the upper limit of the controller.   *search for "Max solar input voltage" if you want to read up on it's purpose. Otherwise panels are hooked up using nominal voltages to work in conjunction with other components in the system, eg. your 24 volt battery bank.

Also, that controller automatically detects 12 or 24 volts and switches accordingly, if it is reading anything different then........

  And if you want to run long distances you can increase voltage by putting 10 in a string and using larger inverters as opposed to small controllers.  But you still must conform to 120, 240 etc volts.
  The way your doing it would be like saying you can use any voltage coming off your breaker panel at home because you have a 200 amp service so it should be able to handle any voltage appliance you want to put into it, eg. plugging in a 12 or 9 volt appliance into a 120 outlet.
 

Posted by Tom M on Sep 27, 2015 07:43 pm

#2 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: newbie, here! had an oddly low state of charge
24 volts!!!!!! What gauge wiring comes from the panels?  Connecting two in series will not increase wire gauge significantly. Not sure why you can't understand, very simple.


so 3 strings...24 volts...200 watts ..8 amps per string...with 12-14 gauge wire...to the combiner block......for a total of ....24 amps..so 10 gauge wire from the combiner to the controller

http://www.sunforceproducts.com/Support%20Section/Solar%20Panel%20&%20Charge%20Controllers/24WireGaugeSelectionTable.pdf
 

Posted by Tom M on Sep 27, 2015 07:30 pm

#3 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: newbie, here! had an oddly low state of charge
hard to tell if you fried the controller or not...best to disconnect everything and start over...follow the manual on hook up...as mentioned battery bank first then rewire your panels for 24 volt.....then connect them to the controller ..then see what happens
 

Posted by Tom M on Sep 27, 2015 07:24 pm

#4 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: newbie, here! had an oddly low state of charge
first you should check output voltage from the panels...confirm 24 volts...then hook up your batteries to the controller....then hook up your pv to the controller....you can check output to the batteries from the ports on the controller...you should be getting 24 volts....though if your batteries are connected the reading will be 24 volts anyway unless you have a disconnect between the controller and the batteries then you can check it there.....
......indicator lights on the controller should confirm all inputs and outputs

stepping up voltage is common to reduce wire gauge size as long as all voltages are in sync.....
 

Posted by Tom M on Sep 27, 2015 05:36 pm

#5 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: newbie, here! had an oddly low state of charge
look on page 22. it shows max solar input for 12 and 24 volts...operating voltage.....the 100 v is what it can handle max input without frying it. ..just like the V oc on your panels. it's always higher than operating voltage and is the max it will output without being connected to anything..the mppt part of the controller is to adjust for varying sun over the course of the day, not the input voltage....are there any lights flashing on the controller?
 

Posted by Tom M on Sep 27, 2015 04:40 pm

#6 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: newbie, here! had an oddly low state of charge
Not sure about that 100 volt input to the controller you mention or the reasoning behind inputing 56.7 volts. Perhaps you can give the model number or link to the manual. Otherwise as I mentioned in my previous post

"Rewire your panels for two panels in series (24 volts) sent into a combiner box, then out of the combiner into the charge controller, then out of the controller to the batteries."

Not sure why you are thinking you can just add any amount of voltage into the controller, unless that is how it works. Never heard of one til now.
 

Posted by Tom M on Sep 27, 2015 02:42 pm

#7 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: newbie, here! had an oddly low state of charge
Well my first inclination is your pv setup. 6 - 100 watt panels- 12 volt should be set up in strings of two, if you are setting up for 24 volts. You said you had 4 panels in series so that would make 48 volts,  or as you mention, 2 strings of 3 = 36 Volts, so perhaps your charge controller is not working properly. If I am looking at the correct controller, it can be set for 12 or 24 volts only and draws 10mA to operate.
 Check any overcurrent device, fuses, relays etc to see if anything tripped.
 Rewire your panels for two panels in series (24 volts) sent into a combiner box, then out of the combiner into the charge controller, then out of the controller to the batteries.
   Read the manual for the controller. Hook up your batteries first. then connect the output from the combiner box from your panels second. Hook up your inverter directly to the opposite end of the battery bank NOT THE CONTROLLER! If you look in the manual it directly tells you not to hook up an inverter, battery charger or high amp load to the controller. You can hook up small 24 volt loads directly to the load terminals if you desire.

So if your charge controller was not working and you had your fridge hooked up to the inverter and the inverter was wired directly to the batteries, then it obviously has been drawing power from the batteries which are not being recharged.

 

Posted by Tom M on Sep 12, 2015 09:44 pm

#8 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: SMK or MC4
If exposed connections are your biggest concern, a simple application of some petroleum jelly may help the cause or some of the dip they use for hand tool handles or perhaps some wax.
 

Posted by Tom M on Sep 4, 2015 12:30 am

#9 -  Renewable Energy > Technical Discussion: Solar Water Pumping > Re: Determining panel size to run shurflow pump
Well, simply 7 amps x 12 volts =84 Watts, so any panel above this should work.
 

Posted by Tom M on Aug 31, 2015 11:28 am

#10 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Question about battery capacity when wired in series vs. parallel
Robert, no. If an appliance is say 48 Watts, if you use 12 volts then it draws 4 amps, if you use 48 volts then it draws 1 amp. Watts=Volts x Amps. So run time would be the same. Operating voltage is usually what drives your setup for both the appliance and the inverter.
The only benefit of using a higher voltage is smaller current so smaller gauge wire, as you mention, which tends to be cheaper and easier to work with.
 

Posted by Tom M on Aug 25, 2015 12:33 pm

#11 -  Renewable Energy > RE General Discussion > Re: Backup solutions for small appliances for 2 to 3 weeks where electricity is NOT
Here's one site with a variety of flexible panels....you should be able to find more....it also has cheap charge controllers.  Just match current and voltage outputs of whichever panel you purchase. They also have some inverters. Sometimes your local automotive store will have some cheap inverters. You should not need a true sine wave inverter, which are more expensive, to run those simple loads. Just check the wattage needed by your appliances. (voltage x current, eg 12 volts x 5 amps = 60 watts, or 220 volts x 5 amps = 1100 Watts), then choose an inverter accordingly.

http://www.solarhome.org/flexiblesolarpanels.aspx

Obviously, you should be able to purchase a deep cycle battery in Haiti.
 

Posted by Tom M on Aug 25, 2015 11:28 am

#12 -  Renewable Energy > RE General Discussion > Re: Backup solutions for small appliances for 2 to 3 weeks where electricity is NOT
Robert, there are a lot of portable, flexible type, thin film type of PV panels available. 'There are some that fold up neatly. This may work for you for the radio (or purchase solar powered radio), computer and phone charging. It may be possible to charge or use these items directly from the panel, or else some type of  adapter or inverter may be needed
For the other items you mention in the room, you may just need a small inverter, depending on the voltages and amps of these appliances. You may also need a battery that can be charged by the same panel and a small,cheap charge controller and a little bit of wire. Not sure if you are able to leave these item behind or perhaps leave them with someone you know when you are gone.
 

Posted by Tom M on Aug 25, 2015 11:14 am

#13 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Next to zero gains at high noon
If it is the monitor you are relying on, maybe it's that, especially if it doesn't show spikes when you turn something on. That monitor can also be switched for current going in and current going out of the battery, make sure you are looking at the correct setting, as well as battery % full. Check fuses and connections on the monitor.

Take a voltage reading of your battery bank, if they are full, then current coming in may be limited. If you can, check the voltage and current coming from the panels at the controller or nearby junction box. Then if you see a problem, start checking panel connections and grounds.
 

Posted by Tom M on Aug 24, 2015 12:54 pm

#14 -  Renewable Energy > Technical Discussion: Solar Water Pumping > Re: Determining panel size to run shurflow pump
Douglas, did you already purchase the pump? If you only need 20 gal / week and that pump does 3gpm then only 7 min of run time. I would think you could get away with a much smaller pump that could run directly off a small PV panel. Wire it to a float switch on your tank. Then it should be able to maintain the level throughout the week.
  What type of head do you have between the water source and the tank? This will drive the model pump you would need.  A small submersible may be all you need. Look at marine or boat supplies or your local hardware store.
 

Posted by Tom M on Jun 27, 2015 12:13 pm

#15 -  Renewable Energy > RE General Discussion > Re: Need some advice
Cecelia, well I'll start with the obvious. To save water there are these things called valves or shut off at each faucet, usually under the sink. If you close them slightly, the water flow will decrease and hopefully nobody will notice. This simple method can save a lot of water especially if people tend to leave faucets running while doing other activities. Water levels in toilet tanks can also be adjusted. Water saving washers can also be installed on faucets.
 As far as electricity goes, there are usually light switches located in rooms and on appliances that can be shut off when they are not in use. A simple sign saying to turn them off may work. Day lighting and reflection is your best option to save on lighting cost. Once people get used to natural lighting they may realize they don't need to have lights on.
 Set computer's and  monitors to shut down or go into energy savings mode. This is usually in the computers bios or settings and can be set for any amount of time from the last keystroke or mouse activity.
 

Posted by Tom M on Jun 27, 2015 11:51 am

#16 -  Renewable Energy > Technical Discussion: Solar Heating - Solar Thermal > Re: Solar water heater efficiency?
Robert, you could fill the collector with a known temperature water. Set a time, then drain the water and take the temperature.  Once you have the delta T, the time, then you can figure out how many BTU's that have been gained  q= kA(T2-T1),  where q will be the heat gain (BTU/hr), k is the conductivity of the material (BTU/hr*ft^2*F), A is the area of the collector (ft^2), T2 and T1(F). Then multiply by the time in the collector to determine BTU's gained.

or hook up a small pump to a known temperature water supply in a bucket, circulate it through the panel for a given time and then take final temperature reading, then calculate q again

Also realize that the amount of solar radiation throughout the year changes so your gain will also change over the course of the year. With solar hot water, it's make what you can when you can and use it wisely.
 

Posted by Tom M on Feb 12, 2015 12:23 pm

#17 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: strange phenomena is PV output
Not totally sure what is meant by an insulation warning, but my first guess was a bad ground, which you fixed within the inverter. You may want to check connections between panels for exposed wiring which may be interfering with the ground. Best to go old school and pull out that multimeter and check the voltage on each string first, then narrow it down to hopefully an individual panel that may have a fault.
 

Posted by Tom M on Sep 29, 2014 11:29 am

#18 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: battery bank
Wayne, so 10 amps at 110 volts would be 1100 Watts or 2200 watts if the pump is 220 volts. Using 10 , 200 watt panels would work to run the pump directly or at least maintain the battery you mentioned, ( 40 amps x 8-10 hrs ). If you plan on making such an investment you should also look into using the system year round for other electrical needs when the pool is closed in order to get a better and faster payback.
  Another option is to change your pump motor to one that is DC.
 

Posted by Tom M on Sep 21, 2014 12:37 pm

#19 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: battery bank

Wayne, when you say 8.2 KW do you mean that you have 8000 watts of panels, eg 80 panels x 100 watts each?
 If that is the case then at 48 volts, you are producing around 160 amps. So 8 hrs of sun would give you 1280 amp hrs. , almost three time your battery storage. So that battery bank would be a little small.
 Usually you design a battery bank to have enough storage for three days based on your electrical usage, then size your pv array to be able to recharge the batteries on a daily bases based on your daily use plus enough to keep the battery bank at a full charge.
  So perhaps you can be more specific as to the amount and wattage of panels you are looking to purchase.
 

Posted by Tom M on Jun 26, 2014 02:57 pm

#20 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Simple questions for my RV solar setup:
Brandon, normally you should not mix voltages when connecting different types of panels. The spec sheet on that panel shows a Vmp around 54 volts and a normal operating range of 85% so you may be able to use your existing controller that is rated for 48 volts. Just make sure it has fuse protection just in case.
 You can purchase another controller for the new panel and keep the old controller for your older panel and hook each controller to the batteries, (on opposite ends). This would give you some redundancy should anything happen to either controller.
 Alte should have anything you need and I am sure someone here can help you with any of your needs if you are not sure of the products you have specified.
 

Posted by Tom M on Mar 29, 2014 02:17 pm

#21 -  Renewable Energy > Technical Discussion: Solar Water Pumping > Re: System for Rain Barrel Pump and More
just a quick comment on the rain barrel. If you are just using the storage to water a garden 50 feet away at some small elevation, why do you need a pump? Can you raise the rain barrel to a height above the garden and use gravity instead?
 

Posted by Tom M on Mar 3, 2014 06:26 pm

#22 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Battery Problem
Charles,  that inverter has a connection for a temperature sensor input, with available readout using a MATE, unforturately sold separately. Since you are in a warm climate it is possible that it is shutting down due to temperature. I would suggest getting a temperature reading and compare that to the hi/lo limits for the inverter. Hopefully those values can be found in the manual somewehere.

You could try hooking up the batteries and panels for twelve volts and switch the CC if possible and run some twelve volt DC loads directly off that to see if all other components are working correctly.
 

Posted by Tom M on Feb 23, 2014 03:32 pm

#23 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: 2 solar arrays and one controller
would be nice to have some numbers.....but there should be no problem if you wire them in parallel and the controller can handle the current output....
 

Posted by Tom M on Jan 22, 2014 04:57 pm

#24 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: small off-grid: solar charge controller + inverter compatibility for LVD purpos?
Mike, here is a couple of links for a cheap lvd...

http://www.nemosolar.com/dcsubmersiblepumps/id45.html

http://www.powerplanted.com/12vss.html

Just do an internet search for DC low voltage disconnects and you should be able to find one that fits your needs at a decent price...
 

Posted by Tom M on Jan 22, 2014 02:26 pm

#25 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: small off-grid: solar charge controller + inverter compatibility for LVD purpos?
Mike, I get where your coming from. I have also dealt with instalations in rural areas where systems were not properly used.
 The best way is to use numbers. If you can afford to put a small digital readout for battery voltage then they may be able to visually see that they need to turn off the inverter or whatever lighting or appliance they are using..... Or an inliine low voltage disconnect that leads to the loads for automatic operation.
 

Posted by Tom M on Jan 19, 2014 01:25 pm

#26 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: small off-grid: solar charge controller + inverter compatibility for LVD purpos?
Michael, one thing you didn't metion was the size of your solar PV panel. eg. How many Watts?. This will determine how much power you are receiving daily and therefore how much power you can use daily irregardless of the controller or inverter.
  Your inverter should be hooked up to your battery, not your controlller. A small load such as a light can be hooked up directly to the controller as long as it is within the output power of the controller in combination with the panel.
 You must do the math with regards to how much power you are using each time you use it in order not to drain the system's battery.
There are calculators here at AltE to help you understand this.
 

Posted by Tom M on Dec 28, 2013 11:53 am

#27 -  Renewable Energy > RE General Discussion > Re: Global Energy Network Support GENI
I think trying to interconnect the world energy grid would be a mistake. Just think of all the corruption that would take place. Who would control the energy flow? Who gets what? Who is gonna steal?  More focus should be put on getting individuals to be energy independent. We can't get governments to agree on the simplist of things so why would you want to put them in charge of something of which they have no knowledge? Rememeber these leaders are lawyers and politicians , not electrical engineers.
 

Posted by Tom M on May 25, 2013 12:25 pm

#28 -  Renewable Energy > Technical Discussion: Solar Heating - Solar Thermal > Re: Grounding and Lightning Protection for thermal HW collectors
Dave, if you are using copper piping to and from the collectors, they are pretty much grounded through the plumbing system just as any other fixtures which is why some electrical system parts are grounded onto water mains Adding a conventional grounding stake and proper gage wire shouldn't hurt , it would just add to cost.

Of course if it is possible, you should consider a ground mounted system rather than installing them on the roof, This allows for easy maintenence, installation, adjustment and reduces piping runs.,
 

Posted by Tom M on Apr 30, 2013 12:24 pm

#29 -  AltE > Discussion > Re: DC voltage
Mark, to keep installation cheap, 24 volts is the way to go in my opionion. This allows you to buy off the shelf electrical components at low cost. Higher voltages can be more efficient and reduce wire sizes, but other component cost such as breakers  and the like get more expensive.
 

Posted by Tom M on Apr 30, 2013 12:18 pm

#30 -  Renewable Energy > Technical Discussion: Solar Heating - Solar Thermal > Re: Overheat protection: hot water cylinder / PV
Adam, check out Aquastat controllers. They have a variety of high limit controls for most electrical situations and should be readily available at any plumbing supply.
 

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