Replacing Battery in Innovv C2 with Capacitors

[Yooshaw]

Decided I need to make a thread on this rather than posting in similar threads.

My intent is to get these (I have two) back in action (have been sitting on the shelf over a year since my move to Florida). I initially got these capacitors to try and replace my battery in my Innovv C2.

https://www.aliexpress.com/item/2Pc...32571210201.html?spm=2114.13010608.0.0.fueBnJ

At first tried just one of these, and that failed. Then wired two in parallel, and that worked the first time I tried and it saved the last file - but then it never saved the last file again. On top of that, the two button cells are still too large to fit in the case and close. While I know I can mount the capacitors outside the case, I'm going for a clean install.

I happen to have a dead DDPai Mini 2, so I harvested its capacitors. They look to be the NForce (green), rated at 2.7V 5F (two total). I wired them in series and my Innovv C2 seems to work! So that's great, but these capacitors are way to big and would have to be mounted outside. Also, as @Dashmellow has pointed out in other threads (as have others), cell balancing is a concern (I read through your GT680W thread, great read and info).

I measured the voltages - 4.12V across both capacitors, 2.02V across one, and 2.10V across the other. The difference between the two capacitors has me concerned.

So, I started looking for a new capacitor, and ran across this one on Mouser:

http://www.mouser.com/ProductDetail...EpiMZZMuDCPMZUZ%2bYlxdFextp0taVSY%2b6ovCDBq4=

It's dimensions look perfect to fit in the space I have for the C2, and the 15F should be plenty. One of the features listed is "No cell balancing necessary."

4.2V is right on the edge of the max voltage though. There is a 5.6V version, but it's length is too long too fit. Thoughts on running a 4.2V capacitor? Is that too close to the operating voltage? The datasheet indicates that it can tolerate 4.8V for up to 30 sec. Anyone know if Vishay make quality capacitors (I would hope so for over $11 for one)?

 

[Kip]

I was looking at the Vishay ones for my project, until I read the datasheet. Apparently, max charging current on the 15F 5.6v (4 cell) caps is really low, something like 50mA, and max discharge is also low at around 70mA if I remember correctly. Only the 45F and 90F ones appear to be suitable for the high power use that our cams would require (possibly 500mA or more but you'd need to measure the exact current to know for sure).

4.2v would be a bit close, you could put a resistor in series to lower the charging voltage a bit if you really can't fit a 5.6v cap in.

I plan on running some spare RC heli batteries in mine for a little while as the cam is new to me, so, just want to test it out first before buying an expensive cap.

 

[Yooshaw]

Thanks for pointing that out on the Vishay - didn't notice the charge current ratings. I'm no expert and I'm certainly learning a lot by tinkering with this, but I thought one of the benefits of capacitors was their ability to put out high volumes of current? Never thought a capacitor would have a max rating for current.

For fun, I'm going to try and measure at what current these nForce caps are getting charged and discharged at.

 

[Kip]

Thanks for pointing that out on the Vishay - didn't notice the charge current ratings. I'm no expert and I'm certainly learning a lot by tinkering with this, but I thought one of the benefits of capacitors was their ability to put out high volumes of current? Never thought a capacitor would have a max rating for current.

Yeah I was pretty surprised as well! I guess not all caps are made the same, could be one of the reasons some of them wear out quickly when fitted to a battery designed dashcam.

For fun, I'm going to try and measure at what current these nForce caps are getting charged and discharged at.

Should be interesting, I'm going to do the same tomorrow hopefully when I fit the spare RC batteries and see what's going on. Might have to actually solder my multimeter to the charging circuit though as I have no croc/alligator leads and keeping the camera working with those sharp probes in contact would be very difficult.

EDIT: Just had another thought. Try testing the amp draw when the batteries or caps are flat as that is when they will draw the most current from the camera.

 

[Yooshaw]

Yeah I was pretty surprised as well! I guess not all caps are made the same, could be one of the reasons some of them wear out quickly when fitted to a battery designed dashcam.



Should be interesting, I'm going to do the same tomorrow hopefully when I fit the spare RC batteries and see what's going on. Might have to actually solder my multimeter to the charging circuit though as I have no croc/alligator leads and keeping the camera working with those sharp probes in contact would be very difficult.

EDIT: Just had another thought. Try testing the amp draw when the batteries or caps are flat as that is when they will draw the most current from the camera.

That's what I was going to do - get the capacitors drained and measure as it charges the capacitors. Then drain again and measure the output side as the dashcam is running.