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Super Capacitor

Roo

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Feb 19, 2020
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Any one using super capacitors for devices with large start up requirements? In my case a 1.5 hp deep well pump. It takes a heap of energy to start, about 4 times the energy required to run. It appears that a correctly designed super capacitor should make this task more efficient in terms of actually starting the pump, time to start pump and load drawn from battery bank. I have made the calculations and ready to build, but can't find anyone who's actually done it for comparison. It seems that super capacitors implemented in solar systems is an area that is currently under explored. Perhaps I haven't looked thoroughly. Thanks in advance.
 
The pump is 220vac 50hz, driven by a 4, 000w inverter. Anything smaller won't kick it over.
 
supercapacitors are supe exepensive, so probably you would better put the money in a bigger battery or bigger inverter.
 
Not where I am, S. E. Asia, far cheaper than batteries or a bigger inverter (very expensive here, solar is a relatively new tech in my area). I only need enough voltage to match my 24v batteries. Cost is diy @ au$20.00. Don't know offhand what this in us$.
 
The pump is 220vac 50hz, driven by a 4, 000w inverter. Anything smaller won't kick it over.
This is what I thought I do not know if super Caps can be used as a an AC mechanism. But if you had a full bank of DC superCaps they would not increase the Inverters max surge power.
 
yes, but usually it is about the size of wire and battery.
the inverter is designed to go well over the specs for a few seconds, the time is just about how much the thing can heat without being destroyed.
but if you wiring and battery is designed close to the inverter capacity, any surge will first impact wire and battery (voltage diving low ---> inverter failure).
you can test it by connecting the pump very close the inverter and see if it goes better.
then you can check wires going from battery to inverter. You wires are probably undersized , because in normal use it does not matter, so most of us use undersized wires.
try to double the wires and check again if it goes better.
after you can check for the battery size. if the 1C is close or under capacity of inverter, it is possible the surge is asking 4 or 5C to the battery and the battery is unable to deliver.
in that case, yes, supercapacitor could help.
 
yes, but usually it is about the size of wire and battery.
the inverter is designed to go well over the specs for a few seconds, the time is just about how much the thing can heat without being destroyed.
but if you wiring and battery is designed close to the inverter capacity, any surge will first impact wire and battery (voltage diving low ---> inverter failure).
you can test it by connecting the pump very close the inverter and see if it goes better.
then you can check wires going from battery to inverter. You wires are probably undersized , because in normal use it does not matter, so most of us use undersized wires.
try to double the wires and check again if it goes better.
after you can check for the battery size. if the 1C is close or under capacity of inverter, it is possible the surge is asking 4 or 5C to the battery and the battery is unable to deliver.
in that case, yes, supercapacitor could help.

Please provide the spec sheet that shows an inverter that can handle a high amp draw for more than a few Miliseconds.

Also as discussed in other threads the instantaneous high draws that most inverters can handle is within the inverters own capacitators.

Obviously the batteries and wire need to handle current. If sized properly the wires still can not make up for an insufficient inverter size.

How long do you think the well pump is going to draw high amps for?
 
if it is inrush current due to motor start up, it should not be more than 2 or 3 sec.
for the inverter, you just need to read the specs, but most inverter can provide up to 50% for a few minutes and 200% for a few sec.
MosFet transistors are very insensitive to current especially when they are in the open state, but they are very sensitive to voltage.
basically , the problem is only with tracks on the printed board or size of wire. Very often when you burn an inverter for overload, it is
not the mosfets who die first.
Anyway, supercapacitors will not help since they are a substitue for battery and are before the inverter.
so if really the inverter is insufficient, supercapacitors will not help.
 
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Thanks for the replies. I think some have misunderstood my intentions and I have omitted a fact. The inverter handles the job just fine, starts and runs the pump without difficulty. * My intention was to simply make a more efficient system.* My cabling is fine, I've gone oversize and yielding maximum current from battery bank to the inverter. Is the theory sound or a waste of time? Anyone implemented super capacitors? I have only seen one such installation online and obviously can't test it.
 
I don't understand what is so hard to understand about using a capacitor.

Don't use it INSTEAD of a battery, it is not a battery.
Use WITH a battery. It will do exactly what you want it to do, send a massive surge current for a short time when you need to start something.

These things have been used in car stereo bass drags for decades.

And buy the tool for the job.
You want a batteryless solar inverter for a well-pump.

 
Well, bad example.
The people purchasing capacitors for the boom-boom stereo of their car are the same using ultra expensive extra thick oxygen-free copper cable with gold terminals because it "sounds" better.
I do not think we need this type of marketing in DIY solar.
 
Well, bad example.
The people purchasing capacitors for the boom-boom stereo of their car are the same using ultra expensive extra thick oxygen-free copper cable with gold terminals because it "sounds" better.
I do not think we need this type of marketing in DIY solar.
It doesn't just sound better, big bass draws way more current. The capacitor provides it.

But yes the oxygen free wires are bullshit.
 
Any one using super capacitors for devices with large start up requirements? In my case a 1.5 hp deep well pump. It takes a heap of energy to start, about 4 times the energy required to run. It appears that a correctly designed super capacitor should make this task more efficient in terms of actually starting the pump, time to start pump and load drawn from battery bank. I have made the calculations and ready to build, but can't find anyone who's actually done it for comparison. It seems that super capacitors implemented in solar systems is an area that is currently under explored. Perhaps I haven't looked thoroughly. Thanks in advance.

There is a few utube vedeo on the subject, if you look in there, you will find, I did a while back, I've ordered 24 supercapicator 2.85v 3400f 2 months ago and I'm still waiting for them. I will be installing them with two new banks of lfp, also ordered. It will save your batteries and good for your inverter as well I would say because the supercapicator discharge quickly as compared to batteries to take care of the surge.
Hope this helps

I just took a minute and found it, this is one of the first one I seen when I built my system.


There's a lot more if you follow the links.
 
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Thanks for that, confirms my understanding of the concept. I will now proceed with the modification.
 
I would consider it if the batteries were struggling to start it as they could provide that initial grunt after which the inverter would cope fine. As far as increasing efficiency goes I don’t think it will make any difference. Power is power and capacitors won’t affect that. If it were a case of using them to prevent micro cycling on an inverter battery with a heavy load and solar then the answer might be different as then they do make a difference.
 
Thanks for that, confirms my understanding of the concept. I will now proceed with the modification.
Hi Roo, I was just wondering if you did add a supercapicator bank to your system and if so, have you seen a positive impact on your current draw.

I have installed a supercapicator bank on my system and I concluded that it does help out on the power surges, especially for the motor starts, sump pump, furnace fan motor, microwave,. Anyways I'm happy with the improvement. Also current bing drawned from the capacitors is larger at the start of the motor, meaning this current is not drawned from the batteries so saving the amp, in battery storage. It took 6 1/2 months to get the capacitors, they have been installed now for three weeks.
 
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