Grid Down, Battery Dead
- Thread starter Damn Yankee
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Damn Yankee
New Member
Hey Folks,
I realized I wasted an opportunity to learn rather than (as now I read it) defend my position - not what I set our to do. Remember, I don't care about night, I realize there may be weeks without sunlight, and I want to power 3 things...
To those who are saying "Battery", even if was short on capacity, I now ask why? I've read some posts or blogs that say excess power needs to go somewhere, therefore you need batteries and I say "BS". There is no power if there is not voltage and current. As proof to doubters I ask "OK, what happens in a sunny day at noon, no load, and the batteries are on float? Nothing. The panels go to max voltage and collapse. Many have said "things fry" and I ask "what things?".
For an Off-Grid system:
I get it some electronics will not like the fluctuations of a say a cloud, but I am talking about two inductive loads (motors) and a microwave. I might lose my microwave one day, but the motors will spin on. If I am judicial (say using switches for priority) the well pump or compressor will get full attention. I can look at the sky and see a cloud is approaching and shut things down. And I don't have the overhead of 60A charging batteries - that power is strictly for on-demand essential service. And why can't I oversize my array for the needed bump to start the motor?
Please, what do I have wrong here?
John
After this, I would like to shift to the solar water for thoughts if you allow as it is an interesting topic and I blew it off - sorry - but don't want to wander yet. You Folks are experienced and helpful and I have been not thinking and defensive. May we start anew?
I realized I wasted an opportunity to learn rather than (as now I read it) defend my position - not what I set our to do. Remember, I don't care about night, I realize there may be weeks without sunlight, and I want to power 3 things...
To those who are saying "Battery", even if was short on capacity, I now ask why? I've read some posts or blogs that say excess power needs to go somewhere, therefore you need batteries and I say "BS". There is no power if there is not voltage and current. As proof to doubters I ask "OK, what happens in a sunny day at noon, no load, and the batteries are on float? Nothing. The panels go to max voltage and collapse. Many have said "things fry" and I ask "what things?".
For an Off-Grid system:
- PV (no power at open or short)
- DC-DC converter which regulates the voltage to the Inverter. (Perhaps if the No-Load Voltage of the panels is higher than the DC-DC converter allows, it would pop, but I wouldn't spec the system as such).
- Inverter to convert DC to a sinewave and is regulated by load - too less Z, it goes into foldback. Battery Charge Controller optional and in my case not required (unless there is a sound argument why I have to have one).
I get it some electronics will not like the fluctuations of a say a cloud, but I am talking about two inductive loads (motors) and a microwave. I might lose my microwave one day, but the motors will spin on. If I am judicial (say using switches for priority) the well pump or compressor will get full attention. I can look at the sky and see a cloud is approaching and shut things down. And I don't have the overhead of 60A charging batteries - that power is strictly for on-demand essential service. And why can't I oversize my array for the needed bump to start the motor?
Please, what do I have wrong here?
John
After this, I would like to shift to the solar water for thoughts if you allow as it is an interesting topic and I blew it off - sorry - but don't want to wander yet. You Folks are experienced and helpful and I have been not thinking and defensive. May we start anew?
Basic electrical theory will tell you that for a given wattage (power doing work) if your voltage drops the current (amperage) must rise. Thus a motor doing work can quickly get overloaded if you drop the supplying voltage to it (cloud passing over). Trying to avoid this by turning things off manually when your solar panels drop production is going to take more control than a person can reasonably sustain. Nobody is that aware and ready all the time.
Compressors are a real problem since they demand a higher starting current to get the motor spinning. So now you have the effect of sudden higher current that drops voltage which means the current must rise higher, which further increase voltage drop, and the motor just sits there and heats up to destruction.
Batteries in the system can alleviate the effect because they can sustain sudden load current demands. However even then batteries will have a voltage drop. The higher the load the more voltage drop you get at a given temperature.
Incidentally there is a lot of information in the solar world that is apocryphal. Do not believe everything you read.
Vigo
Solar Addict
This is kind of funny but if i had to i would rig a rope-assist start onto certain things. I have a cheap belt sander and a concrete mixer that often wont start without a little help, and ive also done things like run bench grinder on a 100ft extension cord, or ‘10amp’ saws on a 700w generator (hmmm) all of which worked with a little human powered pre-spinning of the armatures in question. The startup surge was ME. ?
And if i had a marginal setup that i MIGHT be able to get over the hump with a little rope and pulley id rather do that than go without. So you might consider ‘human-assist’ motor starting as a possible survival skill, on some level..
I would also consider adding flywheel weight to a generator engine to increase its motor-starting potential..
What about some kind of pneumatic water lifting system for the well? An air tank is a lot like an extremely cheap battery.. you can fill it with the dinkiest thing you want (just adds time) but the discharge intensity is only limited by the size of your plumbing. Lots of people will be able to compress air after all the batteries are gone. There might be something about the surface tension of water that allows with a small enough pipe to ‘pump’ water to the surface trapped between bubbles that you pumped into the system below the water level at a relatively low pressure. Something like this? https://www.drillawell.com/air-powered-pump
And if i had a marginal setup that i MIGHT be able to get over the hump with a little rope and pulley id rather do that than go without. So you might consider ‘human-assist’ motor starting as a possible survival skill, on some level..
I would also consider adding flywheel weight to a generator engine to increase its motor-starting potential..
What about some kind of pneumatic water lifting system for the well? An air tank is a lot like an extremely cheap battery.. you can fill it with the dinkiest thing you want (just adds time) but the discharge intensity is only limited by the size of your plumbing. Lots of people will be able to compress air after all the batteries are gone. There might be something about the surface tension of water that allows with a small enough pipe to ‘pump’ water to the surface trapped between bubbles that you pumped into the system below the water level at a relatively low pressure. Something like this? https://www.drillawell.com/air-powered-pump
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Damn Yankee
New Member
I have to my surprise, a driller as a neighbor. I already found an AC/DC submersible for deep wells that has soft start. he is familiar with that item. He also has another in mind which uses a VFD. Both are made for my purpose - Off Grid. I'll report after I meet with him.
John
John
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