Are there any capacitor-based power banks that don't use batteries?

rjk

Member
Joined
Aug 28, 2013
Messages
40
Reaction score
31
Location
uʍop ǝpısdn
Country
United States
I'm interested in knowing whether anyone has developed a power bank that has only capacitors inside, instead of being based on batteries like usual. I know it would take up a lot more space for the same capacity, but the reason I want this is because it could charge completely during a short trip, and then last a long time in parking mode.

A normal battery-based power bank could take quite a long time to charge up if it is completely dead. If my daily trip is only 5 minutes long, that's not enough time to charge the battery bank. However, it might be enough time to completely charge a capacitor bank if it had a smart current limiting circuit on it. What do you guys think?
 
... I know it would take up a lot more space for the same capacity,...

You have absolutely no idea... ;) Look at "Energy density".
 
You have absolutely no idea... ;) Look at "Energy density".
No I'm serious, I do know that it would probably be the size of a group 24 lead acid battery, I just wanted to know if anyone had made one already.
 
10000mAh (5v) capacity will require ~70 pcs of 2.7v 500F supercaps 35 x 60 mm each.
Ok thanks for doing that calculation. I didn't think the density was quite that bad. I guess that would take up the entire trunk of my car, so that wouldn't be an option. Oh well.
 
It would also require the entire maximum output of your alternator to charge in that time and give 24 hours runtime, which probably wouldn't end well!

Not a bad idea though, if we could get some power efficient dashcams that use 1/10th the typical power then it would be feasible, and some of the micro-cams can manage something close to that...

... but then we could just use the car battery!
 
Btw: Not to mention 5 minutes trips are not good for car either, if you DIY own powerbank out of batteries used mostly for RC purposes, you are able to get pretty fast charging. Unfortunately there are also lifetime and safety issues...

Isn't better for you to consider a solarpanel? (to extend the time...)
 
  • Like
Reactions: rjk
Btw: Not to mention 5 minutes trips are not good for car either, if you DIY own powerbank out of batteries used mostly for RC purposes, you are able to get pretty fast charging. Unfortunately there are also lifetime and safety issues...

Isn't better for you to consider a solarpanel? (to extend the time...)
Good idea - will look into solar panel options.
 
Btw: Not to mention 5 minutes trips are not good for car either, if you DIY own powerbank out of batteries used mostly for RC purposes, you are able to get pretty fast charging. Unfortunately there are also lifetime and safety issues...
Good idea - will look into solar panel options.
There is still an interesting power source - 12V Lead Acid AGM Rechargeable battery (as UPS for alarm security )
According to AGM (Absorbent Glass Mat) technology, these batteries are completely sealed and safe, unlike lithium batteries, on which PowerBank's are created
Examples: TYSONIC https://www.ebay.com/itm/253486955357, Yuasa https://www.ebay.com/itm/121278264062
These are batteries of the smallest capacity 1,2 Ah, if you choose a capacity of 4 Ah and above, respectively, and the cost will be different
 
There is still an interesting power source - 12V Lead Acid AGM Rechargeable battery (as UPS for alarm security )
According to AGM (Absorbent Glass Mat) technology, these batteries are completely sealed and safe, unlike lithium batteries, on which PowerBank's are created
Examples: TYSONIC https://www.ebay.com/itm/253486955357, Yuasa https://www.ebay.com/itm/121278264062
These are batteries of the smallest capacity 1,2 Ah, if you choose a capacity of 4 Ah and above, respectively, and the cost will be different
Sure, but that doesn't really solve the specific problem that I was targeting - it would charge a little bit, and then discharge a lot, and then charge a little bit, and eventually discharge completely. Current battery tech requires long idle or drive sessions in order to get them charged all the way up in order to last a while in parking mode. I don't know how well a solar panel might work behind tint either - I'm pretty sure I don't want it anywhere on the outside of my car. But I will have to do some research.
 
Tinted window will be a problem. Solar-panel isn't much effective even under ideal conditions so sun angle, tint, dirt, even the glass itself will decrease the effectivity. But it's one of the possible sources...

Another way is just a big battery-pack in your trunk which can handle whole day and then you let it charge over night (in your garage/yard) via charger.
 
Last edited:
Sure, but that doesn't really solve the specific problem that I was targeting - it would charge a little bit, and then discharge a lot, and then charge a little bit, and eventually discharge completely. Current battery tech requires long idle or drive sessions in order to get them charged all the way up in order to last a while in parking mode. I don't know how well a solar panel might work behind tint either - I'm pretty sure I don't want it anywhere on the outside of my car. But I will have to do some research.
The leading advantages of AGM are a charge that is up to five times faster than the flooded version, and the ability to deep cycle. AGM offers a depth-of-discharge of 80 percent; the flooded, on the other hand, is specified at 50 percent DoD to attain the same cycle life.
 
I contacted my local Maxwell distributor to get a quote on their new 3v 3400f caps, and even in quantities of 150 their price is just under $70 each. So this would be super expensive, to boot.

My car already has an AGM battery from the factory, but have to go on an occasional 30m drive to keep it charged up if I don't want to plug it in. I have the camera set to turn off automatically, but my GPS tracker stays on all the time and I think that's how it is killing the battery.

The tracker is only supposed to wake up once per hour in parking mode, maybe I have some other drain as well.
 
What about the second battery and overnight charging?
 
What about the second battery and overnight charging?
Unfortunately my parking spot is far away from power, but since my battery is in the trunk of my car I am going to look into a solar panel on the trunk lid. I wonder if suction cups would be strong enough?
 
That's unfortunate. Depends on a size of the solar panel and how many suction cups do you use... :D
 
Unfortunately my parking spot is far away from power, but since my battery is in the trunk of my car I am going to look into a solar panel on the trunk lid. I wonder if suction cups would be strong enough?

You don't happen to mention which camera you are interested in powering but assuming it is a typical 5V type why not consider using a standard large capacity portable power bank? Personally, I've been using two 20,000 mAh power banks to run four dash cameras in "parking mode" (full time recording) for over four years now. They will run the cameras for the entire day (or longer) if I wanted them to and indeed I regularly leave the cameras running on the power banks after I return to my vehicle and drive off to avoid having to plug and unplug each time I make a stop somewhere.

I've found that it is really not a big deal to bring the banks inside when I return home, charge them during the evening and repeat the process the next day. It's just become a routine daily ritual that I don't find to be a big hassle at this point. My power banks are kept in hard shell (Pelican style) cases and transported in a canvas tote bag with all the other things I need with me for the day which makes the whole process of carrying them around fairly convenient.

I didn't start out expecting to still be doing this after four years as it all began as an experiment but it has been a convenient and very affordable solution for running four dash cams during parking that would have been virtually impossible even with a more sophisticated, expensive solution such as a Cellink which would not handle four cameras.
 
Last edited:
It's a Qvia AR790 2CH and it has a direct 12v connection, no separate power supply.
 
It's a Qvia AR790 2CH and it has a direct 12v connection, no separate power supply.

OK, since you have a 12V dash camera, then consider a 12V power bank. There are quite a few high capacity power banks on the market nowadays compared to only a year or so ago when there were only a couple available.

For your purposes, probably something like the MaxOak 50,000mAh (one of the originals) might be the way to go?

Personally, I have no experience with 12V power banks running dash cams but if you buy from Amazon you could check one out and see how well it works and then return it if it doesn't work out for you. I think the primary issue would be the current requirements for your Qvia AR790 2 channel vs whatever 12V power bank you choose.
 
Back
Top