HK3 hard wire kit - terrible voltage regulation

[bobcat]

Seems that the horrible title of a good product was used for promoting a personal product which finally failed as a project.
Again: good means that is not creating problems to the dashcams or to the cars and RMA, DOA, returns are minimal.
If my HK3 hardwire kit from Viofo is working as expected, not creating problems even it is used for more than 5 years I don't see a reason to buy another product more expensive from an unknow seller. But maybe other people could buy your hardwire kit just because you will present it as made with quality components. Some people can be happy to know that they have the best from the market even the result is the same.

Good luck with your new idea but I hope to present it as an idea and not to blame a good product just to promote your idea.

For now I will replace the old HK3 even it is working like in the first day with the new version of HK3 which was showed in my previous post. I hope the new version to be durable as the first version and last it for another 5 years. If not, I will mount the old HK3 again. I will keep it as backup because never failed on me. I am sure the new HK3 version and the HK5 are better than previous versions, the PCB is looking better.

If you go back to the original posts on my project of a custom hk kit, it was never intended to be sold to masses, to you, or anyone else. Those posts are publicly available and anyone can read it for themselves. I've done it for myself and shared the progress along the journey. I've tested it all in my personal cars, as I would never try to sell anything that I would not be comfortable with myself. (Besides, hell, I'd never afford CE and UL certification costs for these). More over I'm pretty sure I've done more tests on these hk kits and modern car alternators charge behaviors then most users of this forum. I did express curiosity if anyone else would be interested in chiming in to the project. But, I've never promoted or sold a single piece of my hardware to anyone, although I've spent over 500$ in the process of developing prototypes.

So, while being sharp languaged, the point you're trying to make is unclear to me.

I've started that journey purely because 3 (or 4, I don't remember by now) of HK3 kits have failed on me, and I wanted to create something more reliable and something under my control - because I could, and in the process figured out I can make it more smart, and shared my progress.

If you have any more claims to make, I'd be happy to respond.

Cheers.

 

[Mtz]

I've started that journey purely because 3 (or 4, I don't remember by now) of HK3 kits have failed on me

I still don't believe this. It is almost impossible Viofo to send you 3 or 4 hardwire kits and all of them to be broken. Maybe Viofo can have 3 or 4 bad units at 1000pcs.?
Just imagine that Viofo sent 3 or 4 bad hardwire kits exactly to a person who knows how to make such product. They not sent 3 or 4 bad products to average Joe, but to a specialist. Maybe you are the most unlucky person from the world.

And just looking at the thread title, maybe Viofo dashcams have no problems to work with a hardwire kit which has ``terrible voltage regulation``, in your opinion. Maybe that voltage is OK for their dashcam. Maybe for a NASA dashcam is not OK that voltage regulation.

 

[bobcat]

I still don't believe this. It is almost impossible Viofo to send you 3 or 4 hardwire kits and all of them to be broken. Maybe Viofo can have 3 or 4 bad units at 1000pcs.?
Just imagine that Viofo sent 3 or 4 bad hardwire kits exactly to a person who knows how to make such product. They not sent 3 or 4 bad products to average Joe, but to a specialist. Maybe you are the most unlucky person from the world.

And just looking at the thread title, maybe Viofo dashcams have no problems to work with a hardwire kit which has ``terrible voltage regulation``, in your opinion. Maybe that voltage is OK for their dashcam. Maybe for a NASA dashcam is not OK that voltage regulation.

They had a bad batch of these made during covid time. There were plenty of comments and posts about hk kit randomly failing on this forum around the same timeframe. There was even a comment from Viofo later on mentioning they had issues with these.

You've been on this forum long enough, should have known, unless you preferred to ignore it.

So yes, my replacement units as well as purchased separately all came from the same bad batch.

Not sure what makes you so uneasy with the thread name, but I did not create this thread, and it was not my comment. But I do agree with it and experienced some of those issues myself.

 

[v81]

I still don't believe this. It is almost impossible Viofo to send you 3 or 4 hardwire kits and all of them to be broken. Maybe Viofo can have 3 or 4 bad units at 1000pcs.?
Just imagine that Viofo sent 3 or 4 bad hardwire kits exactly to a person who knows how to make such product. They not sent 3 or 4 bad products to average Joe, but to a specialist. Maybe you are the most unlucky person from the world.

And just looking at the thread title, maybe Viofo dashcams have no problems to work with a hardwire kit which has ``terrible voltage regulation``, in your opinion. Maybe that voltage is OK for their dashcam. Maybe for a NASA dashcam is not OK that voltage regulation.

When you grossly and blatantly dismiss actual evidence in this thread, i mean evidence too, not hearsay, oscilliscope traces and actual user reports... How can your opinion now be of any value?
Have you ever submitted any evidence? Where are your scope traces?
Where are your efficiency measurements? Have you got any evidence other than anecdotal that you can report?
I actually would be interested to see your efficiency measurements maybe you can link some of your previous work if any exists?
Mine are on page 2 - https://dashcamtalk.com/forum/threa...e-voltage-regulation.44244/page-2#post-541436
Or maybe you have nothing useful to add, and your test bed consists of plugging it in, snacking the car on the roof and guessing at efficiency?

Not sure what makes you so uneasy with the thread name, but I did not create this thread, and it was not my comment. But I do agree with it and experienced some of those issues myself.

I am the thread creator.

A summary...
As a reminder I created it as a result of having a failed unit, that was replaced by a second failed unit.
I have a home lab with Rigol scope and Linear PSU, a DC load and a few multimeters.
Seemed sensible to pop open the failed units and see what was going on, and I posted the results here.
I collected information and posted my findings with evidence. More it seems than @Mtz has ever done here, yet they still want to claim this is all made up.
I put out a call on several local forums mentioning i'd had a few failed units and a unit putting out too much voltage, and offered to test peoples units if there were interested or having any kind of issue.
A few people sent units over a period of months, not all made it into the summary i previously posted.
At some point a 3rd failed unit was sent to me for testing along with 2 other working samples.

My real intention of this thread is that i might find legitimately curious minds to share my findings with.
None of this is or was any kind or rage bait or to reflect any kind of negativity against Viofo.
Maybe a little hurry up when their Aussie distributor failed to respond to me, sure.
But other users made out as if i was mounting some kind of evil campaign against Viofo.
I'm here for the electronics, the science and the evidence, yet continue to be pulled into drama.

Anyone that can not accept the evidence i have posted as actual failures has no useful place in this thread.
That is not a moderation threat, it's simply a reminder i can block individuals and withdraw my participation at any time.
Anyone that continues to appear as if they want to be emotionally involved in defending Viofo against an attack that I'm not making and they have just brewed in their minds can have a block from me.
Since being online since 1995 I've never blocked anyone online for anything other than spam before, yet i already have 2 in this one forum / thread.
I think this says something about their behaviour rather than mine.

 

[v81]

Hey, thanks for acknowledging my efforts on this! I see there is still a lot of interest around a good hardwiring kit and that's encouraging!
I am happy to share my view on the topic, and why I sort of dropped out from further development (although I have some new ideas for a board that can "do it all").

The main reasons why I've halted the development of my project:
1. Such a board, if using high quality components, let's say from TI for power handling, makes it much more expensive to produce in low numbers.
2. Chinese manufacturers/ assembly shops often don't have access to these components, so some parts would have to be added manually after the main assembly.
3. Adding more features and different parts from the original hk3/4 would require custom enclosure (3d printed in low volumes in my vision). Although doable, but very time consuming.
4. While I can offer to the market a custom regulator board, the peripherals, such as wiring from the car to pcb and from pcb to the camera would have to be arranged by potential customers (which means soldering by the customer). Offering a "plug and pay" solution is impossible in lower volumes. And low volumes would mean hundreds of these boards.
5. Each board would have to be programmed and QCd manually.

I do know there are a lot of enthusiasts on this forum, but even if every single one of you bought such a board from me, I'd probably just break even, after spending hundreds of hours of developing and assembling it. Lower volumes would mean I'd do all that at my own loss (mainly time). Now that being said, I'm exploring a new idea I have in mind, mainly for enthusiasts and without commercial aim and if I manage to find the parts needed to make it happen, I'll be making a new update on this project soon.

I too have started down this path.
And am now replying to this as my parents unit, now a few years old is intermittently failing.
I have also had an email from another HK3 user whose kit i tested and they are having a similar problem.
I have an idea in mind, even had an MPS chip in mind that factored for current drop over the cable.
I shelved the idea in 2022 but am thinking of going into it again.
Problem is i do lack in the area of analogue design, but to compensate i was considering using a uC for low voltage and other general monitoring.
An ATtiny85 or something to sample the voltage once every 50 seconds and sleep inbetween.
But as already suggested, cost will be an issue as will manufacture.
I might knock together a prototype for Mum and Dad and leave it at that.

 

[Ormy]

Hi, having an issue with my A129 pro duo, found this thread searching for solutions.

First, the oscilloscope captures on the first page and the table in post #25 are quite enlightening @v81 I commend you on your work. My knowledge of electronics is not on par with yours but I know how to read a 'scope and that ripple is BAD.

So I've had an A129 Duo (the original 1080p variety) and a HK3 kit both bought in 2019 working fine until the front cam crapped out.

I recently bought a A129 Pro Duo (the 4k variety) since I assumed it would be a drop in replacement (no need to run new cables everywhere) which was correct. Except at first it refused to boot. After cleaning the USB contacts and just manipulating the cable around it finally worked but the backlight on the display flickers heavily when recording, less so in parking mode (3fps timelapse), so obviously I'm thinking undervoltage or current limitation from the HK3, it is 5 years old after all. I was seeing similar but far less severe flickering on the old A129 but I had put that down to the ageing of the camera unit and not the HK3, now I realise that assumption was erroneous.

So I'm doing some searching and come across this thread, my HK3 may precede the bad batch but my eyes have been opened to the cheapness of their design.

My proposed solution is just buy 2x cheap 2amp buck converters off ebay, one for the +5V and one for the ACC. I don't need the voltage cutoff functionality because the dashcam (+5V) runs off a separate battery that has its own battery management system.

Yes I could take out my HK3 and connect it up to a 'scope and try to diagnose and then rectify the issue but I really just want my dashcam to work with a minimum of effort. As I value greatly my parking mode recording duration (hence the separate battery), I'm thinking that even if the ripple on my HK3 isn't 'too bad', the efficiency might still be less (and more than likely be no better) than what I'd achieve with ebay buck converters, correct? I was originally thinking of buying a new HK3 from viofo but after seeing this thread I'm reluctant to do that.

Appreciate any input.

And thanks again to those who have put so much work into this thread.

 

[LateralNW]

Hi, having an issue with my A129 pro duo, found this thread searching for solutions.

First, the oscilloscope captures on the first page and the table in post #25 are quite enlightening @v81 I commend you on your work. My knowledge of electronics is not on par with yours but I know how to read a 'scope and that ripple is BAD.

So I've had an A129 Duo (the original 1080p variety) and a HK3 kit both bought in 2019 working fine until the autofocus on the front cam crapped out (got stuck at a focus point about 4m infront, not bad for 5 years continuous usage really).

I recently bought a A129 Pro Duo (the 4k variety) since I assumed it would be a drop in replacement (no need to run new cables everywhere) which was correct. Except at first it refused to boot. After cleaning the USB contacts and just manipulating the cable around it finally worked but the backlight on the display flickers heavily when recording, less so in parking mode (3fps timelapse), so obviously I'm thinking undervoltage or current limitation from the HK3, it is 5 years old after all. I was seeing similar but far less severe flickering on the old A129 but I had put that down to the ageing of the camera unit and not the HK3, now I realise that assumption was erroneous.

So I'm doing some searching and come across this thread, my HK3 may precede the bad batch but my eyes have been opened to the cheapness of their design.

My proposed solution is just buy 2x cheap 2amp buck converters off ebay, one for the +5V and one for the ACC. I don't need the voltage cutoff functionality because the dashcam (+5V) runs off a separate battery that has its own battery management system.

Yes I could take out my HK3 and connect it up to a 'scope and try to diagnose and then rectify the issue but I really just want my dashcam to work with a minimum of effort. As I value greatly my parking mode recording duration (hence the separate battery), I'm thinking that even if the ripple on my HK3 isn't 'too bad', the efficiency might still be less (and more than likely be no better) than what I'd achieve with ebay buck converters, correct? I was originally thinking of buying a new HK3 from viofo but after seeing this thread I'm reluctant to do that.

Appreciate any input.

And thanks again to those who have put so much work into this thread.

Save yourself all that mucking around and just use the cigarette lighter converter supplied in the original kit.
Pull the unit out of the enclosure and hardwire it in or open it and add wires inside it and hardwire them in.
Tuck it under the dash.

Am I on the right track?

 

[Nigel]

My proposed solution is just buy 2x cheap 2amp buck converters off ebay, one for the +5V and one for the ACC. I don

You don't need a buck converter for the ACC, that only draws micro amps, so a buck converter would be a waste of power. A linear regulator, or just a voltage divider would work fine.

As, LateralNW suggests, the buck converter inside the supplied lighter socket plug will work well, probably better than nearly any you could buy.

The cable is important, and likely the reason why the older HK3 convertors don't work well with the newer camera - the cable has too much resistance.

A new HK3 is the obvious way to solve the issue, not the cheapest solution, but for most people it works fine! The camera does use a fair amount of current and doesn't like low voltage, a cheap buck converter is quite likely to cause issues.

 

[Ormy]

You don't need a buck converter for the ACC, that only draws micro amps, so a buck converter would be a waste of power. A linear regulator, or just a voltage divider would work fine.

As, LateralNW suggests, the buck converter inside the supplied lighter socket plug will work well, probably better than nearly any you could buy.

The cable is important, and likely the reason why the older HK3 convertors don't work well with the newer camera - the cable has too much resistance.

A new HK3 is the obvious way to solve the issue, not the cheapest solution, but for most people it works fine! The camera does use a fair amount of current and doesn't like low voltage, a cheap buck converter is quite likely to cause issues.

Already ordered two buck converters, easier than pulling apart the cig lighter to USB that came with the dashcam and soldering onto the contacts. Was only £7 for two including postage. I will probably still use one for acc, when acc is on the engine will nearly always be on so I don't care about a few lost watts there. Also I can up the output voltage as needed on a buck converter to get a solid 5V under load at the end of the cable, can't do that with the included cig lighter one.

Yes I know the cable is crucial, I will be using thicker gauge cable.

As stated I will not be buying a new HK3 after seeing the evidence posted earlier in this thread.

Thanks very much for the info though.

 

[negronoir]

I had HK3 and dash was freezed from time to time. I purchased a new HK3... And few months later, the same issue.

Finally some months ago I reused the HK3 cable and replaced Viofo HK3 electronics for a 5A buck converter and PCB from a cig lighter for the Acc signal.

Like a charm... No problems since this change.

 

[v81]

My proposed solution is just buy 2x cheap 2amp buck converters off ebay, one for the +5V and one for the ACC. I don't need the voltage cutoff functionality because the dashcam (+5V) runs off a separate battery that has its own battery management system.

Welcome aboard.
I'm in a bit of an information limbo right now.
I want to say not all HK3's are affected, but in recent months my parents working unit is now failing.

I've been considering making my own in small batches, but as mentioned previously there is no economical way to go about this, it would be a $50 - $100 item.
While an established tinkerer i recently have had reason to bring another electronic unrelated item to market in small volume and it's really quite eye opening how much I need to charge just to break even on R&D + manufacture all the way into a finished device packaged and shipped. Another user here was considering the same and they cam to the same conclusion.

Where to from here??
I'd suggest something more robust than a 2A regulator, but 2A might do the job.
As for the acc signal a 78L05, a 1117, a Zenner reg or a resistive divider might do.

Save yourself all that mucking around and just use the cigarette lighter converter supplied in the original kit.
Pull the unit out of the enclosure and hardwire it in or open it and add wires inside it and hardwire them in.
Tuck it under the dash.

Am I on the right track?

I think that will prevent parking mode from working.

You don't need a buck converter for the ACC, that only draws micro amps, so a buck converter would be a waste of power. A linear regulator, or just a voltage divider would work fine.

As, LateralNW suggests, the buck converter inside the supplied lighter socket plug will work well, probably better than nearly any you could buy.

The cable is important, and likely the reason why the older HK3 convertors don't work well with the newer camera - the cable has too much resistance.

A new HK3 is the obvious way to solve the issue, not the cheapest solution, but for most people it works fine! The camera does use a fair amount of current and doesn't like low voltage, a cheap buck converter is quite likely to cause issues.

The HK3's internal reg is designed with line drop compensation, it is supposed to increase the voltage along side an increase in current draw.
A very cool feature, but too many other issues plague the unit.

Already ordered two buck converters, easier than pulling apart the cig lighter to USB that came with the dashcam and soldering onto the contacts. Was only £7 for two including postage. I will probably still use one for acc, when acc is on the engine will nearly always be on so I don't care about a few lost watts there. Also I can up the output voltage as needed on a buck converter to get a solid 5V under load at the end of the cable, can't do that with the included cig lighter one.

Upping the voltage isn't a nice solution, the voltage drop will vary with current draw.
You can get away with it to a degree, but you can only go so far.

Yes I know the cable is crucial, I will be using thicker gauge cable.

The USB cable between the reg and the camera is the issue, not the cable before the reg.
If you were to package you reg nicely you could actually go ahead and shorten the USB cable and install the reg in the headliner of the car only 30cm or so from the camera, this would help.

As stated I will not be buying a new HK3 after seeing the evidence posted earlier in this thread.

Thanks very much for the info though.

Some doubt me, but after 3 failed on the bench and finally getting mum and dad's unit going... only to now fail a year or so later, combined with plenty of other stories of woe I've lost confidence in all variations of this unit.
My BlackVue is still hanging on, but in the future i can see myself changing and making my own power system.

I had HK3 and dash was freezed from time to time. I purchased a new HK3... And few months later, the same issue.

Finally some months ago I reused the HK3 cable and replaced Viofo HK3 electronics for a 5A buck converter and PCB from a cig lighter for the Acc signal.

Like a charm... No problems since this change.

Another anecdote on the increasing pile of HK3 issues.

And there are probably hundreds / thousands more for average joes that don't think to post here.

 

[Nigel]

The USB cable between the reg and the camera is the issue, not the cable before the reg.
If you were to package you reg nicely you could actually go ahead and shorten the USB cable and install the reg in the headliner of the car only 30cm or so from the camera, this would help.

That is not a good idea, the regulator will likely overheat. Even down by the fusebox where it is relatively cool, the HK3 can overheat if the ventilation is blocked by carpet. The result is unreliability, I think because when hot it will start to limit the current to the camera.

If you want to get 2A out of a 2A regulator, you need to keep it coolish.

I think that will prevent parking mode from working.

Some of the Viofo cameras do go into parking mode after 5 minutes lack of movement, but I think the ideal was to just use the regulator from the accessory socket adaptor, which is a good one, and use something simple like a resistive divider for the ACC, which only requires micro amps and doesn't need an accurate voltage.

The real problem with this idea is the lack of a low voltage cutoff.

 

[v81]

That is not a good idea, the regulator will likely overheat.

500 milli watts of waste heat is no big deal in this context.
It will get warm, but it will not over heat.
I often pull 3A/20v from a power bank that has it's reg entirely enclosed in a near air tight enclosure, never been an issue in 5 years I've owned it.
Even at 95% efficiency thats 3 watts of heat, warm to the touch as it should be if it's radiating the heat.

If a reg supplying 1-2 amps overheats even in elevated ambient temperatures it was poorly made.
As long as properly insulated from the car body i wouldn't think twice about putting a reg in the headliner.
Old incandescent globes in cars would radiate more heat.