Super capacitors are a horrible choice for solar. Change my mind

[toms]

I use supercaps in parallel with my LiFePO4 pack to reduce surge current from electric motors, and to eliminate AC ripple from Inverter charging.

I also use a 16V supercap as a jump starter for farm equipment (trucks/tractors etc) nice and light, fast to recharge- and should outlast me.

They definitely have a purpose.

 

[Supervstech]

Look here...

$3142.00 for (32) 280aH 3.2V GRADE A, Fresh Manufactured, DELIVERED by Alithor New Energy CO

OK - so I will let you know how this turns out -- incredible price ... did allot of research into Alithor New Energy company and they are a BATTERY MANUFACTURER and not a reseller or vendor. They say that they will test each battery before shipping for all the tests that I require ... they sent...

diysolarforum.com

If my math is right... that is 29KWh for less than $3200 delivered...

 

[DerpsyDoodler]

Number of gullible people has increased, quality of lies and obfuscation has increased. Technology stays the same.

Technology most definitely does not stay the same...but the lies and obfuscation progress along with it..

 

[billw]

Are you referring to Kilowatt Labs "Super-Capacitors"?

In short I'd call them a scam:

Arvio 3.5kWh drop-in-battery-replacement supercapacitor on sale - Page 5 - AEVA Forums

Supercapacitor energy storage and energy server from KiloWatt Labs - Page 4

Supercapacitor energy storage and energy server from KiloWatt Labs - Page 4

www.eevblog.com

Number of gullible people has increased, quality of lies and obfuscation has increased. Technology stays the same.

Where do you live? Technology stays the same? Trolls not needed here so please bother someone else.

 

[electric]

Where do you live? Technology stays the same? Trolls not needed here so please bother someone else.

OK, let me use more words for better clarity - In the context of this thread and since beginning of this thread the technology discussed in this thread has not changed. There are still very expensive and mostly useless for energy storage super-capacitors, and there are various lithium batteries, which are much cheaper and much more suitable for energy storage.

Also, products advertised by Kilowatt Labs are not based on capacitors, even if you add magic prefixes like super or nano. You would know this if you knew what "capacitor" was and how it's different from electro-chemical phenomenon we call "battery", even though this word is technically a misnomer.
One look at the datasheet of these snake oil products tells any electrical engineer everything they need to understand that it's not based on capacitors.
But enough of my trolling, let us all hear how you can't find a 4kWh lithium battery cheaper than $5600.

 

[Roswell Bob]

A "super capacitor" is a horrible choice for solar energy storage because:

- Horrible energy and volumetric density.

- The price per kwh is outrageous. Super capacitors make lithium batteries look cheap.

- Cycle life are great, but just like LTO, you need to factor in calendar aging. And solar batteries only need to be cycled once a day, so it is pretty pointless to have 1 million plus charge cycles when calendar aging will kill your pack long before cycle life is reached.

- Discharge and charge rate are amazing, but guess what?! Any normal, off the shelf lead acid or lithium battery charge and discharge rate will support loads and required charge rate in a properly designed system. No reason to get excited unless you have a tiny battery system.

Capacitors are great as a buffer for reducing noise in a circuit or pushing surges with a small battery. That's about it.

What I want to know is why so many people online are obsessed with them. They are great for specific applications, but nothing to get excited about. Can someone change my mind? Am I missing something?

You are spot on. No one will change your mind.

 

[billw]

OK, let me use more words for better clarity - In the context of this thread and since beginning of this thread the technology discussed in this thread has not changed. There are still very expensive and mostly useless for energy storage super-capacitors, and there are various lithium batteries, which are much cheaper and much more suitable for energy storage.

Also, products advertised by Kilowatt Labs are not based on capacitors, even if you add magic prefixes like super or nano. You would know this if you knew what "capacitor" was and how it's different from electro-chemical phenomenon we call "battery", even though this word is technically a misnomer.
One look at the datasheet of these snake oil products tells any electrical engineer everything they need to understand that it's not based on capacitors.
But enough of my trolling, let us all hear how you can't find a 4kWh lithium battery cheaper than $5600.

Thank you.

 

[billw]

Thank you.

My $5600 is for two 3.55 kwh units and I do have a minimal amount of knowledge regarding the difference between lithium battery and capacitor construction. I am not an electrical engineer and therefore don't understand the conclusions you derive from their datasheet information. I live in Hawaii and I will let you know that almost any item that has to do with an "electro-chemical" battery is much more costly here than on the continental U.S.. I'm open to any information to save money and have a reliable non-FLA system.

 

[electric]

My $5600 is for two 3.55 kwh units and I do have a minimal amount of knowledge regarding the difference between lithium battery and capacitor construction. I am not an electrical engineer and therefore don't understand the conclusions you derive from their datasheet information. I live in Hawaii and I will let you know that almost any item that has to do with an "electro-chemical" battery is much more costly here than on the continental U.S.. I'm open to any information to save money and have a reliable non-FLA system.

This entire forum was created exactly to help folks in your situation. I can only suggest to read as much as possible, find someone's success story that matches your needs and try to follow their successful path. Most people here get their cells or batteries shipped long distance, so your location should only effect shipping cost, not the price of the battery. Decide if you want to buy plug and play battery or make your own DIY style. Voltage is the first key decision, everything flows from there. Then capacity in AH or WH at a given voltage, which decides cost, weight, volume. Much to learn...

 

[Diysolar123]

My $5600 is for two 3.55 kwh units and I do have a minimal amount of knowledge regarding the difference between lithium battery and capacitor construction. I am not an electrical engineer and therefore don't understand the conclusions you derive from their datasheet information. I live in Hawaii and I will let you know that almost any item that has to do with an "electro-chemical" battery is much more costly here than on the continental U.S.. I'm open to any information to save money and have a reliable non-FLA system.

The less knowledge (or comfort learning) about electricty the more you want to buy a "prebuilt" system...
Make no mistake, the power that is contained in electrical storage and power production systems can be deadly (or very expensive when it goes poof).

regarding shipping, well, hawaii is "closer" to the source of pretty much all electronics/batteries (except tesla) so I am not sure how that is a factor??
We all buy from china (when it comes to business, USA politicians are idiots and china is king of the hill)...I think larger batteries "must" travel by container ship; no flying allowed.
(ok, maybe your local politicans have enacted some crazy import regulations...yea, I could see that happening).

This thread about supercaps was just for grins and giggles. I am reasonably sure nobody "really" thinks they are for long term energy storage hehe

diy path is always the cheapest(unless you blow things up hehe); 6kw capacity with an all-in-one will run you about $2000-$2500 for a nice lifepo4 setup.

 

[amaclach]

The only place I would have a use for them is in conjunction with your batteries, to help lessen any surge/dip when a load is applied. Can't see using them as a battery replacement.

But wouldn't flooded lead acid be better (cheaper) than super capacitors for temporary drawdown surge?
example - I want an espresso machine in my truck and it wants to pull more amps than my LiFePO4 can supply for the 30 seconds it needs to run, so the surge pulls from the FLA (then charges back up at whatever rate it's comfortable with). LFP has enough capacity, just not enough oomph to run that espresso machine for 30 secs.
I do seethe super cap jumpstarters being useful, but niche case.

 

[billw]

This entire forum was created exactly to help folks in your situation. I can only suggest to read as much as possible, find someone's success story that matches your needs and try to follow their successful path. Most people here get their cells or batteries shipped long distance, so your location should only effect shipping cost, not the price of the battery. Decide if you want to buy plug and play battery or make your own DIY style. Voltage is the first key decision, everything flows from there. Then capacity in AH or WH at a given voltage, which decides cost, weight, volume. Much to learn...

Thanks for the help. My issue IS knowing just enough to know I don't know nearly enough to make qualified decisions as to what fits my situation the best. Unfortunately I also don't want to be the victim of solar salespeople (posing as solar system experts) which is why I am here.

 

[billw]

The less knowledge (or comfort learning) about electricty the more you want to buy a "prebuilt" system...
Make no mistake, the power that is contained in electrical storage and power production systems can be deadly (or very expensive when it goes poof).

regarding shipping, well, hawaii is "closer" to the source of pretty much all electronics/batteries (except tesla) so I am not sure how that is a factor??
We all buy from china (when it comes to business, USA politicians are idiots and china is king of the hill)...I think larger batteries "must" travel by container ship; no flying allowed.
(ok, maybe your local politicans have enacted some crazy import regulations...yea, I could see that happening).

This thread about supercaps was just for grins and giggles. I am reasonably sure nobody "really" thinks they are for long term energy storage hehe

diy path is always the cheapest(unless you blow things up hehe); 6kw capacity with an all-in-one will run you about $2000-$2500 for a nice lifepo4 setup

 

[billw]

The less knowledge (or comfort learning) about electricty the more you want to buy a "prebuilt" system...
Make no mistake, the power that is contained in electrical storage and power production systems can be deadly (or very expensive when it goes poof).

regarding shipping, well, hawaii is "closer" to the source of pretty much all electronics/batteries (except tesla) so I am not sure how that is a factor??
We all buy from china (when it comes to business, USA politicians are idiots and china is king of the hill)...I think larger batteries "must" travel by container ship; no flying allowed.
(ok, maybe your local politicans have enacted some crazy import regulations...yea, I could see that happening).

This thread about supercaps was just for grins and giggles. I am reasonably sure nobody "really" thinks they are for long term energy storage hehe

diy path is always the cheapest(unless you blow things up hehe); 6kw capacity with an all-in-one will run you about $2000-$2500 for a nice lifepo4 setup.

I can't nor want to show you how many companies "do not ship to Alaska/Hawaii". I'll revisit later today after I've visited all the solar and battery suppliers on my island.

 

[Supervstech]

I can't nor want to show you how many companies "do not ship to Alaska/Hawaii". I'll revisit later today after I've visited all the solar and battery suppliers on my island.

I’m sure it is all about population. There are more buyers in mainland USA than Hawaii and Alaska combined...
there are several you tubers that are based in Hawaii that use solar, and wind. Look them up and see options.

 

[Roswell Bob]

I use supercaps in parallel with my LiFePO4 pack to reduce surge current from electric motors, and to eliminate AC ripple from Inverter charging.

I also use a 16V supercap as a jump starter for farm equipment (trucks/tractors etc) nice and light, fast to recharge- and should outlast me.

They definitely have a purpose.

Your lithium batteries shouldn't need any help with surge currents. They have a very low internal resistance. They are used in high pulse operations. The shipboard 275kW laser uses them. I designed a 30kW charger for the Navy. They were very concerned with ripple current into the cells. I'm not so sure the ripple should be a real concern. The AC components of the ripple current do add to the battery heating though. I'm curious as to what drives your concern for the ripple. Did you read a paper? The charger I did was 6 interleaved chargers each running at 400kHz - so the effective ripple frequency was over 2MHz. I didn't realize super capacitors were used in the jump starters though. Good intel.

 

[billw]

OK, let me use more words for better clarity - In the context of this thread and since beginning of this thread the technology discussed in this thread has not changed. There are still very expensive and mostly useless for energy storage super-capacitors, and there are various lithium batteries, which are much cheaper and much more suitable for energy storage.

Also, products advertised by Kilowatt Labs are not based on capacitors, even if you add magic prefixes like super or nano. You would know this if you knew what "capacitor" was and how it's different from electro-chemical phenomenon we call "battery", even though this word is technically a misnomer.
One look at the datasheet of these snake oil products tells any electrical engineer everything they need to understand that it's not based on capacitors.
But enough of my trolling, let us all hear how you can't find a 4kWh lithium battery cheaper than $5600.

So that everyone can hear, I can't find a 4kwh lithium battery at all on the island of Hawaii for ANY price. If you, or anybody, know someone here I would contact them ASAP.

 

[toms]

Your lithium batteries shouldn't need any help with surge currents. They have a very low internal resistance. They are used in high pulse operations. The shipboard 275kW laser uses them. I designed a 30kW charger for the Navy. They were very concerned with ripple current into the cells. I'm not so sure the ripple should be a real concern. The AC components of the ripple current do add to the battery heating though. I'm curious as to what drives your concern for the ripple. Did you read a paper? The charger I did was 6 interleaved chargers each running at 400kHz - so the effective ripple frequency was over 2MHz. I didn't realize super capacitors were used in the jump starters though. Good intel.

There are several studies on the effect of AC ripple on Lifepo4. I use an AC coupled system, so the supercap removes the ripple.

I try to limit the discharge current to <1C on my packs. The pack i use for my bore pump and RC aircon is standalone, and using a supercap allows me to use a 100ah pack instead of a 200ah pack and still not see greater than 1C discharge current.

The 16V supercap is used as a standalone jump starter. It is not in conjunction with any other energy source, although i know many people using a supercap/lifepo4 hybrid for applications like farm machinery/boats where they get occasional use and Pb batts require ongoing trickle charging which is not always practical.

 

[svetz]

There are several studies on the effect of AC ripple on Lifepo4....

Okay, I had to follow up on that to see about LiFePO4! Here's what one 2019 ref said...

...all this effort presupposes that AC ripple constitutes a serious problem, when it is still unclear to what extent the LIB lifetime may be reduced by the presence of 100 Hz ripple current. While many studies claim that AC harmonics accelerate the degradation of LIBs, there are others that refute this. ...This paper presents the results of a detailed and systematic experimental study on aging impacts of 100 Hz-ripple currents ...The results show that the superimposed 100 Hz ripple currents do not cause a significant amount of degradation on LFP cells.

Of course, that's only 100 Hz ripples... still good to know!

 

[electric]

Your lithium batteries shouldn't need any help with surge currents. They have a very low internal resistance. They are used in high pulse operations. The shipboard 275kW laser uses them. I designed a 30kW charger for the Navy. They were very concerned with ripple current into the cells. I'm not so sure the ripple should be a real concern. The AC components of the ripple current do add to the battery heating though. I'm curious as to what drives your concern for the ripple. Did you read a paper? The charger I did was 6 interleaved chargers each running at 400kHz - so the effective ripple frequency was over 2MHz. I didn't realize super capacitors were used in the jump starters though. Good intel.

The caps are sometimes needed for the sake of equipment, not the batteries. In my experience some systems are not ideally suited for short distance between battery and inverter, resulting in long DC cable runs, which results in high ripple, which results in inverter problems such as overheating of their internal DC input capacitors, internal ripple alarms, etc. This happens on large systems with over 10kW of power when inverter must be placed over 10ft away from batteries for whatever reasons.
Another factor is that people want more power, but can't go higher DC voltage, so they end up with high amperage. There is a voltage gap in residential inverter market in US due to strict and expensive safety regulations.