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rugercpl
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# Posted: 22 Aug 2014 08:19pm
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I have a solar generator thats working fairly well to power my cabin...300ah battery power and (2) 150W solar panels. Its a system designed and sold by Be Prepared Solar...an Ebay company that also sells systems and components via their website and I believe Amazon. I'm new to solar world, and added this system on to the cabin recently to relieve some of the runtime of my Eu2000, and to have silent power in the night. I dont have sufficient sun or solar panels to recharge the battery power I use the night before. but about a 3 hour runtime with the Eu2000 will do that just fine the next morning...but I get about 6 hours of lights, TV, Bluray, radio, and water pumps in the evenings which will deplete the batteries to about 70%-80%. I havent been able to tell how much full sun I would need to recharge the batteries to the same degree the 3-hour recharge runtime does with the Eu2000 using the battery charger to recharge the batteries.
The system design is here... http://www.bepreparedsolar.com/Pure-Sine-Wave-Solar-Generator-Solar-Panels-p/3-300psw .htm . I bought a Shumaker battery charger from them for about $50. I'm using the solar generator to power the cabin via backfeeding the cabin through a dedicated household outlet. In turn the battery power runs thru this outlet to the panel box and electrifies all the outlets and LED track lighting in the cabin.
I'm "getting to know" the battery charger and how it works. I'm also "getting to know" the solar charge controller and how it works, but some things are still a mystery to me. I realize that both the charger and the solar charge controller are what some may deem cheap pieces of junk.
My concern is that I'm possibly losing battery power either through the inverter or through the solar charge controller, because ive noticed that after fully charging the batteries with the generator and charger, and showing a voltage reading of about 13.4-13.6, that after a half-day or so the voltage reading will drop down to about 12.7...even with no power being used, the inverter turned off and nothing plugged into it. If I use the eu2000 and battery charger to recharge the batteries back to a 13.4 to 13.6 voltage reading, it will take as much as an hour. This was noticed on a cloudy day...where I would assume the solar panels would at least "maintain" the full-charge and 13.4-13.6 voltage reading. The drop to 12.7 was a bit of a surprise. I have read that battery power can be lost by bleeding back through the solar charge controller to the solar panels, but I thought I read my solar charge controller prevents this..(as cheaply as it is).
I wonder also if i can lose battery power because the outlets throughout the cabin are powered...even though I am not using any of them. Certain things are plugged in using stand-by power such as the LED flatscreen, a Roku, and mobile hotspot, but these in my opinion should only use a trivial amount of battery power and not cause a significant loss...but I dont know. Perhaps the inverter uses a lot of power just being left on, regardless that there are so few watts if any are being used by it.
thanks for your help enlightening me to the solar world!
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razmichael
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# Posted: 22 Aug 2014 09:18pm
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Hi rugercpl
I'll give you a short answer to some of your concerns from my limited experience. yes, an inverter left on will draw some power (although many new ones will go into a power save mode). All the things you have running will slowly draw you down BUT - without really knowing your usage, you should have a fairly decent amount of power to play with based on your system. Big thing to understand is that the 13+ voltages you are seeing are not the real voltages but what you get during and after a charge. Once the battery settles then you will see the "real" voltage. In fact, on an open circuit, 12.7 volts is considered full. I would suspect when you are seeing an hour to get the batteries back up to 13.?, as you say, the charger is really only topping things up (and this is done at a slow rate).
Lots of good sites to research - my favourite is "the 12 volt side of life" - bit out dated but still really good info.
12 Volt Side of Life part 1.
My system is similar in size to the one you have (slightly more panels, less batteries) and I am finding that I have no problems fully charging the batteries, despite using a vacuum, pump, cell phone booster, the odd blender etc etc. I have not needed to run the generator yet.
Hope this helps. At the cabin now so about to go out and look at the stars.
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rugercpl
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# Posted: 22 Aug 2014 09:32pm
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Helpful! perhaps I am going a bit overboard by trying to fill the batteries to the tippy-top. i'll try recharging to about 12.8 and see what difference it makes in nightly average drainage and morning generator recharge. I think the charger reads about 12.7 to 12.8 when its display shows a 95% charge level. I have always felt the need to push it past 95% which the system seems to get hung-up on during recharge for an extra long period of time. Not sure why that last 5% takes sooooo long.
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razmichael
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# Posted: 23 Aug 2014 08:18am
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The reference and other sources will explain why the last 5% takes so long. Just be really careful using the displayed voltages during charging to determine the % complete. Remember that the charge voltages will range up to 14.x depending on the battery type (make sure your chargers are set for the AGM types) and the stage of the charging (again, well explained in the reference).
At 8 this morning my system is showing over 13 volts because the panels are starting to produce some voltages (limited amps). I also know that the batteries were at 12.6 at 3 this morning when I needed to "go" (beer after dinner - not good for a full night sleep at my age).
You might just try to let the system do it's stuff. If you are a little careful on usage (turn off lights etc) then see if your panels can replenish during the day and only use the generator during cloudy or heavy use times. You may be surprised.
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MtnDon
Member
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# Posted: 25 Aug 2014 09:01pm
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Quoting: rugercpl Not sure why that last 5% takes sooooo long.
That is a normal characteristic of a lead acid battery. The final percentage charge takes much longer than the bulk of the charge. That is where solar is very good. If a generator must be used because the PV panels are not sufficient it is best to run the genrrator in the AM and then let the PV finish off. Best as in the best use of the gasoline.
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MtnDon
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# Posted: 25 Aug 2014 09:06pm
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Quoting: rugercpl a voltage reading of about 13.4-13.6, that after a half-day or so the voltage reading will drop down to about 12.7...even with no power being used,
...what razmicheal said... 12.7 would be considered a full charge after the batteries have sat unused overnight.
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