Supercapacitor Battery Replacement

[Ecky]

For whatever reason, supercapacitors seem to be harder to find now than they were 5 years ago. However, lithium has come a long way. Granted it can still melt down, but LiFePO4 is much less likely to.

I took a chance on some $12usd shipped AliExpress 20Ah cylindrical cells, and assembled a pack out of them. So far, they appear to exceed their rated specifications.

[redpoint5]

Originally Posted by Ecky

I took a chance on some $12usd shipped AliExpress 20Ah cylindrical cells, and assembled a pack out of them. So far, they appear to exceed their rated specifications.

$12 each cell? What is the size, because the biggest I could ever find is 32700 at 7.2Ah. I paid something like $4/cell, but that was before the WuFlu.

Where did the case come from?

The problem I'm having is that the wiring for balance circuits is the opposite polarity of balance leads for external chargers. I have to decide to either wire it for a balance board, or wire it for external charging/cell voltage output, but not both.

I just got a UPS for myself, for Christmas, and am looking to replace the lead acid battery with LiFePO4.

[Ecky]

Originally Posted by redpoint5

$12 each cell? What is the size, because the biggest I could ever find is 32700 at 7.2Ah. I paid something like $4/cell, but that was before the WuFlu.

Where did the case come from?

The problem I'm having is that the wiring for balance circuits is the opposite polarity of balance leads for external chargers. I have to decide to either wire it for a balance board, or wire it for external charging/cell voltage output, but not both.

I just got a UPS for myself, for Christmas, and am looking to replace the lead acid battery with LiFePO4.

Search for "Soshine 40135". I would have gone for the Liitokala cells, which are reputedly legitimate and come with threaded posts, but none of them were available with reasonable shipping to New Zealand. The Soshine cells so far appear legit but you need to use either a (strong) tap welder, or use the cells in a lower current application where it's acceptable to use spring contacts to connect them.

The case is one I'm reusing. I had a powersports battery which failed when I left my Miata with a body shop for a few weeks. They ran it dead and jump started it multiple times, which eventually cooked the cells.

[Ecky]

These are the cells I used:

https://www.aliexpress.com/item/1005...21431802QENEyV

Were I to do it again, I might give these a try, simply for ease of assembly:

https://www.aliexpress.com/item/1005...KRbXKRbO8&mp=1

You may be able to find a better deal on the Liitokala cells. I can't easily see the shipping rate to the US.

[redpoint5]

Originally Posted by Ecky

These are the cells I used:

https://www.aliexpress.com/item/1005...21431802QENEyV

Were I to do it again, I might give these a try, simply for ease of assembly:

https://www.aliexpress.com/item/1005...KRbXKRbO8&mp=1

You may be able to find a better deal on the Liitokala cells. I can't easily see the shipping rate to the US.

Must be new formfactors, as a Brave search says that 32900 are the largest cell sizes available.

The 46135 (25Ah) looks to be the perfect size to replace motorcycle batteries, and the stud posts makes it simple to assemble.

I had no idea there were better options available. I'll have to stock up now before tariffs hit.

EDIT: I've got an order in for the 46135 even though I can't find any info on these things. Found a few results for 40135, but I figured I'd take a gamble on the more unknown thing and report back here.

Here's what I ordered;

https://www.aliexpress.us/item/32568...Cquery_from%3A

[Logic]

I really don't get the lack of interest in this thread..?
IIRC around 98% of car travel is urban trips of under 50 miles. (80km)

As everyone knows:
Force is Mass X Acceleration.
A decrease in mass means less force required for the same acceleration.
And less force is less fuel consumption.

Therefore, on average; weight reduction is the number 1 means of reducing fuel consumption and comes before anything that adds weight.
Boat tails etc that add weight only help at constant speed, or 2% of the time.

The pictured battery obviously decreases weight.

On top of that the conversion of electrical energy in chemical (battery) energy and back to electrical is above 90%, vs 50% for lead acid.

So this battery does not just the 1 most important thing for duel economy, but 2!
So where is everyone?

[freebeard]

Personally, I'm looking at used Arcimoto FUV prices.

They seem to be holding their value really well, except for one Facebook listing in McMinnville for $1000.

[redpoint5]

Originally Posted by Logic

I really don't get the lack of interest in this thread..?

38,050 views. I'm not sure your threshold of appropriate interest, but I'm impressed.

As everyone knows:
Force is Mass X Acceleration.
A decrease in mass means less force required for the same acceleration.
And less force is less fuel consumption.

Therefore, on average; weight reduction is the number 1 means of reducing fuel consumption and comes before anything that adds weight.

Most fuel consumption isn't spent overcoming inertia though, but drag. The most drag is caused by aerodynamics, followed by mechanical friction. Weight is perhaps the 3rd most important factor, and further diminishes in importance for hybrids, EVs, and PHEVs that are capable of capturing the majority of inertial energy when decelerating.

aerohead chose the correct handle, and problem to focus on, because it's the biggest one, and also a nice play on words.

Finally, it seems the supercapacitor momentum fizzled out a while back. New and better products haven't come out, and prices have gone up. Tesla purchasing Maxwell hasn't resulted in anything new except elimination of some of their product line.

I'm bummed there hasn't been much more to talk about on the subject, which is probably why we started talking about LiFePO4.

Finally, none of my newer vehicles use a starter motor, and therefore have low "cold cranking" needs. Buffering a LiFePO4 battery with a supercapacitor is unnecessary when it only needs to close a high voltage contactor long enough to power up the DC/DC converter.

Originally Posted by freebeard

Personally, I'm looking at used Arcimoto FUV prices.

They seem to be holding their value really well, except for one Facebook listing in McMinnville for $1000.

What's the $1k one in McMinnville? Price is too good for it to be in reasonably good shape.

[freebeard]

Price is too good for it to be in reasonably good shape.

Presumably. I wasn't going to click a Fecesbook link to find out.

There were those five flood-damaged FUV at the factory. The only value I heard from them was maybe $500 once the insurance was settled. I'd have gone all Rich Rebuilds on one of those.

So long as i wasn't salt water. The Bonneville Flats did a number on my Superbeetle, fording brine creeks.

[Logic]

Originally Posted by redpoint5

38,050 views. I'm not sure your threshold of appropriate interest, but I'm impressed.

Oh! I shoulda checked that. That is impressive!
Still it's strange to me that there are so few posts.
Lithium batteries should already in the same shops as Lead Acid car batteries as an upgrade/alternative and std equipment on new cars IMHO.

The price of lithium battery packs for cordless power tools points to prices being about the same for the same energy density here, meaning economies of scale have come into play.

People are taking advantage of that.
eg: This RYOBI 40-Volt lithium-ion high-capacity battery to E-bike 'adapter'
https://github.com/pittxprojects/ebike

Originally Posted by redpoint5

Most fuel consumption isn't spent overcoming inertia though, but drag. The most drag is caused by aerodynamics, followed by mechanical friction. Weight is perhaps the 3rd most important factor, and further diminishes in importance for hybrids, EVs, and PHEVs that are capable of capturing the majority of inertial energy when decelerating.

In city, stop-go driving in a std gasoline car?
I've seen stats saying that 98% of trips are under 50 miles, but no maths on overcoming inertia vs aero drag vs rolling resistance.

Google AI overview after a quick search:
https://www.google.com/search?q=In+c...t=gws-wiz-serp

When driving in a city, the energy spent on overcoming inertia is greater than the energy spent on overcoming aerodynamic drag or rolling resistance:
https://www.sciencedirect.com/topics...g%20resistance.
https://www.combustion-engines.eu/pd...20real%2Dworld
https://www.uselessgroup.org/sectors...st%20important.

Here's a breakdown of how fuel energy is used in a car:

Transmission and driveline
Slightly more than 5% of fuel energy is lost in the transmission and other driveline components.

Inertia
About 6% of the energy that reaches the wheels is used to overcome inertia.

Aerodynamic drag
About 3% of the energy that reaches the wheels is used to overcome aerodynamic drag.

Rolling resistance
About 4% of the energy that reaches the wheels is used to overcome rolling resistance.

And who want's to 'look after' and park etc a boat tailed car on a shopping outing..?
DBD seems far lighter and more practical to me.

Regen in a EV or HEV certainly complicates the question!
I'd say that's a question for a different topic.

Originally Posted by redpoint5

Finally, it seems the supercapacitor momentum fizzled out a while back. New and better products haven't come out, and prices have gone up. Tesla purchasing Maxwell hasn't resulted in anything new except elimination of some of their product line.

I'm bummed there hasn't been much more to talk about on the subject, which is probably why we started talking about LiFePO4.

Finally, none of my newer vehicles use a starter motor, and therefore have low "cold cranking" needs. Buffering a LiFePO4 battery with a supercapacitor is unnecessary when it only needs to close a high voltage contactor long enough to power up the DC/DC converter.

Ye... It's a pity.
There is a good bit of info on DIY 'roll your own' supercap on the net.
Not all of it BS as far as I have seen/can tell. So there's another topic for the forum.

In an EV it seems a shame not to buffer the batteries with supercaps.
Capture more regen energy and save the battery from high discharge rates when accelerating.
Perhaps the power added doesn't offset the extra weight and space.
Apparently this is called Hybrid Energy Storage System (HESS) and is a thing still.

All this could use its own topic.