HK3 hard wire kit - terrible voltage regulation

[v81]

I thought that was camera powered down current, effectively the power used by the GPS module, low voltage cutoff was a lot less when I measured it...

Nope, the 3mA is with nothing connected to the HK3, no camera, no load, nothing at all.
edit- The 3mA above was from the screen of the lab supply, have re-run the test with the multimeter.
On mode, no load connected - 6.09mA
Cutoff mode, no load connected - 3.01mA

I reran my low voltage power cutoff tests with the VIOFO HK3 today. I tested all of the voltage selections (12.4/12.2/12.0/11.8) and all of them behaved the same.

I've reworked the video and in it I show a test run of the HK3 with it set to 12.4 volts for the cutoff voltage level.

I start off the test by powering up the dash camera by simulating a "car start" event. I then turned off the accessory power supply (ignition off) and the VIOFO A129 Pro camera would go into parking mode. After the A129 was in parking mode, I would reduce the voltage level provided by the power supply in multiple steps. I would test each voltage level for 120 seconds and then reduce the voltage again and wait again. When the voltage level was reduced to 0.1 volt below the HK3 configured value, the HK3 would cutoff power to the dash camera after a 95 to 100 second waiting period.

I've uploaded the updated video my YouTube channel.

Top stuff.
The minute and a half is a long time, but given the nature of the intended scenario it's probably not bad at all.
Gives the camera every chance to run as long as possible without any transients or extended momentary sags crossing below the threshold.
Your testing method as described sounds spot on and your last video quality (picture, sound and content) was great, will watch the new one in a minute.

Sadly not heard from Viofo yet.
Might get dad to contact the seller, they might have a relationship with Viofo.

If anyone in Australia is reading this i'd love to get hands on additional units, working or not, for additional testing.
I suspect even working units have this terrible regulation, but would also like to test for efficiency as well.

 

[v81]

I know our dashcam PS's are rather simple, cheap, and nasty devices but that's more like an earthquake than ripple....
....I don't expect great things here, but this is more than a little bit shocking to me. 2.59V avg vpp is NOT regulation, it's madness.

Sorry i missed your post, I don't know what's going on but it's as if new posts are popping up between existing posts at least from my perspective.
Maybe this forum threads things in ways I'm unfamiliar with.
I'm actually surprised these units power the Navman we have here.
That said the test with the Navman unit was done before i took them to the bench.
Now that I've seen the madness (simply a fair and honest description, that not an overstatement) I wouldn't plug one of these into anything other than a load.
It goes to show just how tolerant some cams can be of poor power supplies.
I suspect this is normal for these, and the examples i have are just so bad the A129 can't tolerate it.
I'm really keen to get a unit that does successfully power an A129 and do the same tests on it.

 

[IAmATeaf]

Interesting read. Could you guys also do a test where the supply voltage is actually below the cutoff voltage and then go into parking mode. I’ve read previously that in cases like this the HK3 never cuts out as the supply voltage was already below the threshold.

 

[v81]

Could you guys also do a test where the supply voltage is actually below the cutoff voltage and then go into parking mode. I’ve read previously that in cases like this the HK3 never cuts out as the supply voltage was already below the threshold.

Just tested with low voltage cutout @ 12.4v
Batt power simulated at11v
Acc power simulated at11v
Unit cuts out in approx 110 seconds, pretty much same as usual.

Also tested to see if unit would cut out at 11v with acc still connected, unit does not cut out.
This scenario however is unlikely, only thing i could think that might replicate this is a very very sick vehicle electrical system, maybe a bad ground.
Can't really fault it, seems to do the right thing.

Ultimately just rotten voltage regulation is the only flaw in it i can see.

 

[v81]

So for those not fully understanding this i have spent some time testing a number of randomly selected voltage regulators and power supplies around the home and car.

Some may already understand these figures, for others I'll explain.
Power, measured here in watts, a universal measurement of power regardless of voltage and current.
Efficiency is how much power in vs out 75% to 95% is ballpark reasonable for a switch mode power supply, higher is better.
Ripple in power supply terms is the amount of voltage swing from minimum to maximum at a given voltage output.
No power supply has a perfectly still voltage output, a battery measured with nothing else attached is probably the closest to being perfect, but even minor environmental factors and local electrical noise will cause measurable ripple.
Switch mode regulators by their nature typically cause a higher amount of ripple that linear regulation, but this negative is offset by their efficiency.
Ripple is usually measured in millivolts (0.001 volt) as it's usually a small number. Sub 100mV is acceptable for most things, Sub 20mV is very nice for a switching reg.
Vmin and Vmax Minimum and Maximum voltage recorded (in this case taken from a Vmin and Vmax average). Ideally for 5v we want to see the regulation maintain +/- 10%, so Vmin 4.5v or greater, Vmax of 5.5v or less.

Here is the data that i collected in plain form.
Lab supply - Rigol DP832
Scope - DS1054Z
Load - this time a new unit that arrived today from Ali Express, added bonus it had a mini usb port.
All devices that had a fixed cable (HK#'s for example) have now been tested at the end of the cable.
This will account for most variances from original tests.

	Power in (W)	Power out (W)	Efficency (%)	Ripple (mV pp)	Vmin (V)	Vmax (V)	Notes
Ebay PSU A .5A	2.87​	2.5​	87.11​	22​	4.92​	5.04​
Ebay PSU A 1A	5.7​	4.99​	87.54​	31​	4.95​	5​
Ebay PSU B .5A	2.71​	2.49​	91.88​	43​	4.88​	5​
Ebay PSU B 1A	5.47​	5​	91.41​	45​	4.88​	5.04​
12v to USB noname .5A	3.2​	2.5​	78.13​	27​	4.92​	5.01​
12v to USB noname 1A	6.12​	4.93​	80.56​	26​	4.84​	4.92​
12v to USB Belkin F8Z445 .5A	3.58​	2.52​	70.39​	68​	4.92​	5.08​
12v to USB Belkin F8Z445 1A	6.96​	4.94​	70.98​	65​	0​	0​	Ripple reducing by small amount over time - Output failed about 1 min into 1A load
12v to USB Belkin F8J002 .5A	3.13​	2.52​	80.51​	24​	4.93​	5.04​
12v to USB Belkin F8J002 1A	5.97​	4.96​	83.08​	16​	4.88​	4.96​
HK3 #1 .5A	3.2​	2.61​	81.56​	1580​	4.4​	6​	Powers Navman dashcam
HK3 #1 1A	6.97​	5.32​	76.33​	2260​	4.12​	6.48​	Fails to operate Viofo A129 Pro Duo for more than ~ 40 seconds on average.
HK3 #2 .5A	3.26​	2.62​	80.37​	1790​	4.28​	6.12​	Powers Navman dashcam
HK3 #2 1A	7.3​	5.33​	73.01​	2600​	4.04​	6.64​	Fails to operate Viofo A129 Pro Duo for more than ~ 20 seconds on average.

And here is the data on a chart.




Safe to say the HK3's I have here despite working for a camera with lower power demands are quite poor.
Still keen to test a HK3 known to work woth a Viofo A129 Pro Duo setup and report my findings.
Also after looking around keen to test one of the similar looking Street Guardian hard wire kits.
I don't have a huge budget, so would rather borrow and return a unit, preferably one known to work.
If anyone can help with this let me know.
Keeping open minded a properly working hard wire kit might not exhibit this behaviour.
But i suspect the PCB / circuit designer/manufacturer has some answering to do.

 

[Nath]

That's a really nice research!

I'm still thinking about your HWK measurement, no doubt about the output of your lab power supply (i'm perfectly aware of the specs) but have you tried to measure the HWK connected to a battery ("the true ripple-free source" )?

 

[SawMaster]

If not directly battery-powered, at least with one 'floated' across the output. I know this sometimes helps in removing 60Hz ripple in radio transmitter audio. It shouldn't matter with a good lab-grade PS like is being used here but strange things do sometimes happen.

Needn't re-test everything, just the HK3. It would solidify the test results by positively proving it has nothing to do with the power input.

Wishing I was nearby to let @v81 have a go with all the PS's and HWK's I have but I'm half a world away

Phil

 

[DAP]

Another useful thing to measure would be the voltage dropout that the A129 pro can continue working with. Slowly drop the voltage and find out where the A129 pro malfunctions.
I suspect a lot of malfunctions blamed on the A129 pro firmware are really caused by insufficient voltage caused by resistance in the cables.

 

[v81]

That's a really nice research!
I'm still thinking about your HWK measurement, no doubt about the output of your lab power supply (i'm perfectly aware of the specs) but have you tried to measure the HWK connected to a battery ("the true ripple-free source" )?

If i were seeing anything significant across the other supplies to suggest there would be anything significant introduced by the lab supply then this might be worth doing, but it is a 'propper' linear regulated lab supply, honkin big transformer in it, even if not a high end one as opposed to being just a 'bench' supply.
Whilst not a bad idea the result would be no different.
Add to that, a lab supply really is the standard for making measurements like these.

If not directly battery-powered, at least with one 'floated' across the output. I know this sometimes helps in removing 60Hz ripple in radio transmitter audio. It shouldn't matter with a good lab-grade PS like is being used here but strange things do sometimes happen.
Needn't re-test everything, just the HK3. It would solidify the test results by positively proving it has nothing to do with the power input.
Wishing I was nearby to let @v81 have a go with all the PS's and HWK's I have but I'm half a world away

Phil

As mentioned above, if there were something on the output it would be on the other power supply tests too.
Whilst I'm not a professional lab, any professional lab would still test with a lab supply, testing the supply itself directly if need be to rule anything else out (have done this, she's clean as a whistle!).
The testing in the above post was a fresh set of testing done in 1 sitting with the single setup.
I could go off on all kinds of testing tangents, but the results are clear enough as they are.
Would love to test your stuff, would need to get longer test cables though!.

Another useful thing to measure would be the voltage dropout that the A129 pro can continue working with. Slowly drop the voltage and find out where the A129 pro malfunctions.
I suspect a lot of malfunctions blamed on the A129 pro firmware are really caused by insufficient voltage caused by resistance in the cables.

Bench is cleaned up / packed up for now and i don't actually have the A129 here.
Great idea though, and you've basically spoken what i had on my mind.
We're clearly thinking along the same track.
HK3 #1 at 0.5A has a min of 4.4v - and powers the Navman, i mentioned this in the 0.5A test as that about the current draw of the Navman)
Same unit at 1A drops to 4.12v, this is way low, getting a bit close for a 3v3 reg, and if there are any sub circuits running 5v these are probably not happy.
HK3 #2 also powered the Navman, and on a 1A load was worse measuring Vmin of 4.04

These Vmin figures were taken from the statistics display of the scope using Vmin average, tested over 20-30 seconds, the actual Vmin is a little lower.

It's great to see someone draw the same conclusion as I did without me even typing it.
As for testing the the drop-out, a little reluctant, the unit is not mine, and is in use.
If i had spare funds or a loaner then no worries, it would make a great test.

 

[wasyoingonce2]

That's a really nice research!

I'm still thinking about your HWK measurement, no doubt about the output of your lab power supply (i'm perfectly aware of the specs) but have you tried to measure the HWK connected to a battery ("the true ripple-free source" )?

The Rigol PSU is linear with microvolts ripple.

The results basically say the ripple filtering of the HK3 is poor. This manifests in poor efficiency and voltage output regulation. I wonder if they changed something between this and HK2 kit?

Basically the cheap fleabay converters are better. That may be a starting point in modifying the HK3...

cheers

 

[jokiin]

these tests

HK3 #1 at 0.5A has a min of 4.4v - and powers the Navman, i mentioned this in the 0.5A test as that about the current draw of the Navman)
Same unit at 1A drops to 4.12v, this is way low, getting a bit close for a 3v3 reg, and if there are any sub circuits running 5v these are probably not happy.
HK3 #2 also powered the Navman, and on a 1A load was worse measuring Vmin of 4.04

and these results

First install resulted in a camera that functioned for 20-40 seconds and then froze.
Powering it from a USB power bank, or any other Automotive 12v - 5v USB adapter worked fine, so we blamed the hard wire kit.
We receive a 2nd hard wire kit, dad installs it and similar issues.

look to point at faulty hardwire kits, I'd assume they both came from the same supplier so batch issue maybe???

the A129pro is heavy on power compared to the other models so a bad power supply would show up quickly on this model, I'd expect the other models would have issues with these same supplies also, might work for longer on a camera with a battery but would likely cause problems eventually depending on the charge circuit design

 

[SawMaster]

Basically the cheap fleabay converters are better.

Which is what I can't understand here- why would any good dashcam manufacturer send out such a bad HWK when better can be done very cheaply? Couldn't amount to more than $1 per piece to make a vast improvement and that little wouldn't affect sales, while bad PS's will

Batch issue? Maybe, but IMHO equally o9r more likely to be a design flaw with poor in-house testing not catching the problem; the clue being the need for the ferrite choke versus not needing one on the plug-in PS. Very long odds that those two tested units are the 0.01% expected failures from mass-production runs. Even if bad outsourced components are the cause, someone should have caught this at several levels but nobody did And if it is in the design, then solving this one issue might solve several issues across the range of cams which use the HK3, and maybe even the HK3C for the A139 if it uses the same PCB and components.

Even with dashcams, it's GIGO

Phil

 

[jokiin]

Batch issue? Maybe, but IMHO equally o9r more likely to be a design flaw with poor in-house testing not catching the problem;

before it turns into a witch hunt and they get crucified, he has two power supplies that will only run the camera for 40 seconds or so before shutting down, sounds like he got faulty units as that's not normal at all, they've been using the hardwire kits for 2 years or whatever already, limited feedback of similar problems from other users would suggest it's not widespread, maybe they got a batch with some bad components, sucks but it can happen to anyone

 

[v81]

The Rigol PSU is linear with microvolts ripple.
The results basically say the ripple filtering of the HK3 is poor. This manifests in poor efficiency and voltage output regulation. I wonder if they changed something between this and HK2 kit?
Basically the cheap fleabay converters are better. That may be a starting point in modifying the HK3...

cheers

Exactly

these tests

and these results

look to point at faulty hardwire kits, I'd assume they both came from the same supplier so batch issue maybe???

the A129pro is heavy on power compared to the other models so a bad power supply would show up quickly on this model, I'd expect the other models would have issues with these same supplies also, might work for longer on a camera with a battery but would likely cause problems eventually depending on the charge circuit design

They are indeed faulty, both from the same ebay seller.
At glace at the circuit itself suggests these are poor designs to begin with.
My theory is that they might have been used for previous models with great success at lower loads and now they are starting to close in on tolerance and show issues.
Slightly less ripple will power the A129, but that doesn't make them a good unit.

The definition of faulty is interesting though.
If the kits i have here were supplied by Navman to power their camera (and these 2 kits in question do successfully power the Navman) would they still be considered faulty?
No pressure, but I'd love to put the Street Guardian kits on the bench to test. Would you consider sending one or 2, if possible tested to work with your highest power camera or a Viofo A129 Pro in 4K high bitrate mode (if you have one to test).
I've put a bit of effort into this and now really just want to follow it through.

Which is what I can't understand here- why would any good dashcam manufacturer send out such a bad HWK when better can be done very cheaply?

I'm just going to be a straight up realist here.... cost cutting.
Us mere mortals don't understand why someone would go to such lengths, but this is basically it.

Batch issue? Maybe, but IMHO equally o9r more likely to be a design flaw with poor in-house testing not catching the problem; the clue being the need for the ferrite choke versus not needing one on the plug-in PS. Very long odds that those two tested units are the 0.01% expected failures from mass-production runs. Even if bad outsourced components are the cause, someone should have caught this at several levels but nobody did And if it is in the design, then solving this one issue might solve several issues across the range of cams which use the HK3, and maybe even the HK3C for the A139 if it uses the same PCB and components.

Refer above reply to jokiin for my theory.
As for a choke, it's just plain good practice not just for power supply filtering, but for RFI/EMI filtering.
If my theory is correct I'd not be surprised the failure rate of the HK3 in conjunction with an A129 Pro Duo would be quite high, whilst with lower power cameras it might have the rotten ripple, but because they work no one looked into it before.

before it turns into a witch hunt and they get crucified, he has two power supplies that will only run the camera for 40 seconds or so before shutting down, sounds like he got faulty units as that's not normal at all, they've been using the hardwire kits for 2 years or whatever already, limited feedback of similar problems from other users would suggest it's not widespread, maybe they got a batch with some bad components, sucks but it can happen to anyone

Given a glance at the circuit, it's a pretty rotten design, even if they work.
I think I just have combination of a poorer version of a poor design trying to power a what seems like a hungry camera.

Also in my experience how often does knowledge of faults actually make it up the chain?
The seller that supplied our units has just left the faulty units with us, and i's probably reasonable to assume many other sellers do the same.

I'm not looking to do a witch hunt, but I think it's reasonable to call out bad design even if it works in some cases.
And if it results in action we all win, both Dash cam companies with improving reputation on the street and users enjoying a higher likleyhood of having no issues over the product life cycle.

 

[jokiin]

I think a first course of action should be to get a working replacement power supply from @viofo that is made for that camera and then test, testing known faulty power supplies and trying to evaluate the results of how a working one performs is not really fair on them, the seller might not care enough about the result but I would think Viofo should be interested in working it out

 

[Vlad1977]

What if these are counterfeit / knockoff HK3 units? I purchased my HK3 directly from Viofo when I purchased my A129 Pro.

I was also thinking why would a manufacturer put something like this out there.

My HK3 and A129 Pro seems to be working properly. How would someone with only modest tools, check their HK3?

 

[jokiin]

What if these are counterfeit / knockoff HK3 units?

I think they're just faulty, nobody would bother making a knockoff of something like this

 

[v81]

I think a first course of action should be to get a working replacement power supply from @viofo that is made for that camera and then test, testing known faulty power supplies and trying to evaluate the results of how a working one performs is not really fair on them, the seller might not care enough about the result but I would think Viofo should be interested in working it out

It's become a chicken and egg situation.
My father spent about $500 on the package and I now don't want to plug in anything with an unhealthy output, even if it were likely to work for a while.
If I receive a replacement and saw more than 1000mV of ripple could you blame me for not wanting to plug it in even it if did work?
Given how crude the circuit is it's extremely unlikely that these could ever be a healthy option, even if they appear to work.
The possibility does exist that these are counterfeits, but extremely unlikely as you say.
But being counterfeits and finding that there might be a legitimate unit with completely different internal circuitry is the only way this could turn the situation around.

What if these are counterfeit / knockoff HK3 units? I purchased my HK3 directly from Viofo when I purchased my A129 Pro.

Can't rule it out, but seems unlikely.
The BoM cost to make a device like this that uses premium components and design is only marginally more expensive.
Whilst it does not include a low voltage cutout the regs I tested got for as little as 50 cents in quantity.
Quite simply, as jokiin says, making a knockoff of these isn't worth the bother.

I was also thinking why would a manufacturer put something like this out there.

In all honesty, they might just specify some basic requirements and then accept what is offered.
If an electrical engineer were involved in every part of the design, procurement and logistics process this would never happen.
But.... if an electrical engineer were that involved... let's be honest... nothing would get done!

My HK3 and A129 Pro seems to be working properly. How would someone with only modest tools, check their HK3?

You'll need an oscilloscope and a DC load.
Any power supply able to deliver 1 amp at 13.8 volts would do.
Given just how massive the ripple is even a crude $20 approximation of an oscilloscope would find that much ripple.
A local hacker space might be able to help?


Still nothing heard from Viofo after an email and a follow up call.

 

[jokiin]

Still nothing heard from Viofo after an email and a follow up call.

I tagged them in this thread already and they've been online since then so they should be aware, it's in their own interest to follow up with you, perhaps they're doing their own check on this before responding, would like to think so anyway

 

[Nath]

The Rigol PSU is linear with microvolts ripple.

The results basically say the ripple filtering of the HK3 is poor. This manifests in poor efficiency and voltage output regulation. I wonder if they changed something between this and HK2 kit?

Basically the cheap fleabay converters are better. That may be a starting point in modifying the HK3...

cheers

I'm not able to wrap my head around what is so hard to understand about "...(i'm perfectly aware of the specs)...". Btw: Spec says "<350 µVrms/2mVpp" and don't try to stick to the Vrms part, that Vpp matters too. Even though it's great, still worse than battery...

And it was only a question, because i tried to alternate the input to get the same Vpp as OP and i failed. These are not bad equipment, not gonna lie, and HWK is just a cheapo step-down converter, but still it was "designed" for a battery (so no wonder that "ripple filtering is poor"), such device can go nuts even from small discrepancies (especially with the "right" frequency).

Anyway so, as well as @jokiin stated, i don't want be rude, but you can't blame your car for bumpy drive when one wheel is missing... Viofo's HWK is still a crap though...

Another useful thing to measure would be the voltage dropout that the A129 pro can continue working with. Slowly drop the voltage and find out where the A129 pro malfunctions.
I suspect a lot of malfunctions blamed on the A129 pro firmware are really caused by insufficient voltage caused by resistance in the cables.

I tested this before and basically the whole system works at <=3.3V so as (could be) expected A129Pro works even at 3.3V via USB (<3.5V LCD flickers, <3.3V starts to shuting down in 2CH/<3.1V starts to shuting down in 1CH) that was the reason i wasn't buying that whole "lamp cable" solution of yours (more like another HWK Vpp overshoot issue or a cable issue, and the capacity or a better connection of the lamp cable saved the day)