Why would a wireround resistor be needed like with this CAMERA doorbell?

[MrMobodies]

As ambiguous as that statement about requring the 30va power supply in a thread I just started.
https://www.eevblog.com/forum/chat/conflicting-va-information-about-hardwiring-door-bell-on-eufy-websiie/

I Just saw a couple of videos with Youtubers and DIY'ers installing these things recommending to use wireround resistors on this Eufi one (not in the eufi manual) and others, Ring it does) and even searching but can not seem to find the reason WHY.

Here it mentions one in the wiring diagram for a RING doorbell camera.

No reason why without it.

Nothing on the page on the EUFI about requring one
https://support.eufy.com/s/article/How-to-Hardwire-Your-eufy-Wired-Doorbell-without-an-Existing-Wires

Nothing in the manual for Eufi:
https://ankertechnologycompanyltd.my.salesforce.com/sfc/dist/version/download/?oid=00D5g000004DkWQ&ids=0685g000007fnOnAAI&d=/a/5g000000gHI7/.As1GV_d9jcdpQJySXTTjRP4E8y.ibYvpAVsXB6hQ9g&operationContext=DELIVERY&asPdf=true&viewId=05HJ1000001qy13MAA&dpt=

But a Youtube video of someone putting one of these on a Eufi despite it not being required in the manual or website:

3.04 and also i'll be adding a resistor
3:10 this resistor is a 50 watt 24
3:13 25 ohm resistor so
3:16 this will go on to
3:21 either 8 or 24 volts
3:25 so each end will go

Comment:

@mkzayar1836 2 years ago 11 thumbs up
I don't understand fully. Why do you need the resistor for ?

No reply


3:37 in the video

The wiring must be connected to a transformer
with a voltage of 8VAC - 24VAC
and an internal doorbell or resistor.

2.05 in the video

So what are you going to need the resistor.

Very frustrating seeing in the comments, in other videos "oh get one", "I got one", "this is what I need and it was very helpful" etc but NOT WHY.

Can someone PLEASE explain whether or why this would need a resistor and what it does as to opposed without.

Thanks

OOps title edit: wirefound resistor NOT fuse. another mistake with the title. CAMERA doorbell.
Sorry about this.

[shabaz]

Usually the information is pretty vague because the manufacturers hope people use installers rather than do it themselves, and probably the installers might information-hide.

At least from Ring doorbell usage (I can't comment on Eufy, but it might be fairly similar) the resistor was only needed on older doorbells.
On newer doorbells, it's not needed. Nevertheless, I went for the topology where it's powered through a solenoid (i.e. the solenoid inside mechanical door chimes), so there is a bit of resistance in effect. It sips power, just enough to keep it's internal battery topped up, and that small amount of power doesn't energise the solenoid. The Ring doorbell is designed to act like a short across its power terminals (well, close to a short; I imagine it current-limits) when the user presses the button, so that the mechanical chime can work too. Presumably the older doorbells couldn't do that, so they would have to have a resistor if there was no solenoid in series.

I can recommend these parts for a Ring doorbell (specifically the "Ring Video Doorbell 4") because it's been in use for 3 years, with no issue so far.
I used a Friedland E3539N transformer, rated at 12V, and you'll see about 22 V AC on the output with a multimeter, and wired the Ring doorbell, and a mechanical (i.e. solenoid) door chime (Honeywell "Ding Dong D117") both in series. That works great.

If your doorbell requires a similar voltage and has an internal battery, then there may be a good chance that the items mentioned will work for you.

[Kim Christensen]

If the video doorbell is designed to replace the button and ring the original bell, it needs the resistance of the old bell in the circuit. So if the old bell as been removed, it needs to be replaced with a resistor. Otherwise the "video doorbell" will short out the transformer when it attempts to ring the missing bell. (If old bell wires shorted together instead of a resistor there)

[MrMobodies]

I see so this is to do with the bell. I am not sure what's he's got. I think it was a wireless thing he he told me linked to the base but I'll look tomorrow.

Thank you very much for your comments and very helpful.

[shabaz]

If the video doorbell is designed to replace the button and ring the original bell, it needs the resistance of the old bell in the circuit. So if the old bell as been removed, it needs to be replaced with a resistor. Otherwise the "video doorbell" will short out the transformer when it attempts to ring the missing bell. (If old bell wires shorted together instead of a resistor there)

Exactly that (with the slight caveat that I believe/speculate the newer doorbells current-limit so that there won't be a complete short, and they have in any case confused no end of users because they don't explain it, they just say 'no resistor required', but of course many users will instinctively not want to do that when there's conflicting information, old YouTube videos, etc).

I think it's safer all round to just stick in the resistor if there's ambiguity in the instructions of whatever doorbell is being installed, or simply buy a mechanical chime and stick that in series (it doesn't usually hurt to have the extra sound! : )

The first week or so, the battery level needs to be monitored (at least I had to do that with Ring) since it charges slowly, and when it's close to 100%, then it tends to remain approximately there (mine is currently at 95%) and will vary slightly depending on how often it is consuming more power (e.g. if it's facing a busy road maybe), but overall, I've never had the battery deplete (it is not facing a road). It's probably not good for the battery to be charged so fully always, but as mentioned it's lasted 3 years so far, so that's not too bad.

[EPAIII]

Best argument against getting a Ring or Eufi video doorbell I have seen. Thanks for the heads-up.

[Zucca]

worth to mention that in my ring installation I was required to put a "white box" in parallel to the bell.
I assumed it is for trickling energy (lowering the bell impedance) to the ring so that the ring battery can be charged.

[exe]

I can only think of power dissipation. For 24V transformer, 2k resistor will dissipate ~0.3W in the worst case. That's not insignificant. On the other hand, most wire-wound resistors have power rating at least 1W even without heatsink. So, that might be the reason.

Of course, it's better to ask vendor, but playing a guess game is much more interesting)

[Xena E]

When I saw the title I thought it was similar to mine where a high power ww resistor is used to stop condensation within the camera housing...

Quite clearly not! 

[shabaz]

worth to mention that in my ring installation I was required to put a "white box" in parallel to the bell.
I assumed it is for trickling energy (lowering the bell impedance) to the ring so that the ring battery can be charged.

I can imagine that indeed being the case if the specific bell is either electronic, or has high resistance. The simpler bells (the ones that only have a solenoid pretty much! such as that Honeywell model suggestion) are candidates for not requiring any additional resistor.

The current required to flow through the Ring device is low since it charges at such a slow rate, but it will then try to look like a low resistance for a short period when the user presses the button.

[MrMobodies]

There are no wires going to it. He has a wireless sounder a base and that's it.

The screws were so small it kept on slipping out or working their they out on the slightest movement.


Went home to get some clips but found I didn't have the right size which seemed bigger than the screw so I clamped the conductors between two washers with some longer screws that were a a few mm longer to get the thread in as much as possible. I suppose I could have put the clips in with a washer on the top to hold it in place.

I found it very easy to screw the conductors without them moving or slipping out during tightening and sit seems to hold it in very tightly.

I used the, Zyxel JAA-1601000F 16vac 1000mah 16va transformer but forgot to do one thing which I will do tomorrow. Connect a volt meter up, have the owner ring the bell to see it if shorts out. With it connected it shows on the APP that it is charging. It makes a very silent buzzing sound when I put my head near it but it didn't seem to get warm after a few hours. From a watt measuring plug it seems to draw 2watts on it's own and 2.2 to 2.4watt when connected up.

I noticed something that if there is no load it is about 18v but with the video doorbell connected up the voltages goes up to like about 22v.

I got a response this morning and I didn't know Anker owned Eufi.

support=eufy.com@mailbox.eufy.com on behalf of Anker Support mea Team<support@eufy.com>
Dear,

I understand how frustrating it can be to search for specific information without finding clear answers. Let me help clarify this for you. The eufy Wired Doorbell, including the Video Doorbell 1080p, is designed to replace your home’s existing wired doorbell. ** It requires a power supply of 16-24VAC, 30VA or above to function properly.

Key Points to Consider:
Voltage Requirements: The wired doorbell *needs to be powered by wires delivering 16-24VAC, 30VA or above. This is crucial because the doorbell's camera and other features require more power than a traditional doorbell button.

Checking Voltage: You can check your doorbell transformer’s voltage by locating it and reading the markings on it Alternatively, you can use a multimeter to measure the voltage directly. This is the most accurate method. Symptoms of Insufficient Power: If the doorbell doesn’t respond randomly, shows a red or amber ring during setup, works fine during the day but is unstable at night, or reboots when someone presses the doorbell, these are signs that the power supply might be insufficient.
Upgrading the Transformer: If you observe any of the above symptoms, consider upgrading your doorbell transformer. You can find more information on how to do this here.

Wrapwound Resistor:
The context provided does not mention the need for a wrapwound resistor when connecting the eufy Wired Doorbell to a power supply. Therefore, it seems that a wrapwound resistor is not a requirement for the installation or operation of the eufy Wired Doorbell.

If you are still unsure or uncomfortable with the electrical setup, it might be best to consult an electrician to ensure everything is installed correctly and safely.

Ticket# Proceed to specialized service

So wraparound resistor is not a requirement.

This again:

* The wired doorbell *needs to be powered by wires delivering 16-24VAC, 30VA or above.

**The eufy Wired Doorbell, including the Video Doorbell 1080p, is designed to replace your home’s existing wired doorbell. It requires a power supply of 16-24VAC, 30VA or above to function properly.

In contrary to:

Video Doorbell 2K
(Battery-Powered
Model: T8210
Input1: 8-24v ~ 0.2A (from doorbell wires)

Conflicting VA information about hardwiring door bell on eufy website
https://www.eevblog.com/forum/chat/conflicting-va-information-about-hardwiring-door-bell-on-eufy-websiie/

https://support.eufy.com/s/article/How-to-Hardwire-Your-eufy-Wired-Doorbell-without-an-Existing-Wires
Applicable for those products
Video Doorbell 2K (Wired)
Video Doorbell 1080p (Wired)
Video Doorbell 2K Pro (Wired)

For US users: Recommended third-party compatible power adapters:
VIIVRIA 24V / 500mA doorbell transformer
https://www.amazon.com/Transformer-Thermostat-Competible-Versions-Honeywell/dp/B07DJ7RHS5/
12va

Voyaux 16V (18v on picture and title) / 800mA doorbell transformer
https://www.amazon.com/dp/B07PJHVJ2T/
14.4va

https://support.eufy.com/s/article/Hardwire-Your-2K-Battery-Doorbell-for-Continuous-Charging-1617357656298

This guide is to provide you with an alternative method of powering the 2K battery doorbell. If you do not want to take off the battery doorbell for charging via USB cable, you can hardwire the 2K battery doorbell.

I have the existing wires...
To hardwire the battery doorbell, you can see details from Appendix 3 of the Quick Start Guide (from page 19).
The voltage requirement of the 2K battery doorbell is 8-24VAC, 10VA or above. What you need to do is to connect the existing doorbell wires to the terminals at the back of the doorbell, then tighten the terminal screws. The wire can connect to any terminal.

I do not have existing wires...
If you do not have the existing wires, you can purchase a doorbell power adapter for continuously charging. Here are the lists of compatible power adapters: 24V/500mA, 18V/500mA, 16V/800mA.

The 16v one I connected up is 1000 mah, 200 mah more than what's required above on that part of their website.

https://www.reddit.com/r/EufyCam/comments/rm66i5/2k_wired_doorbell_power_requirements/

/EufyCam•3 yr. ago rype89
Wired Doorbell Power requirements
Emailed Eufy quite a bit on this and they eventually tell me that I can ignore the 30VA power requirement if I'm not using existing wires. They recommended *24v/500mA, 18V, 500mA, and **16V/800mA power adapters for use if I did not have existing doorbell wires.

It seems they are not keeping the information clear across the board or consistent between technical support individuals.

[shabaz]

Looks like good progress.
I think they copied the rear to be like the Ring device (or vice-versa), they have a similar two screws on that flat surface.
The Ring device came with two short wires though, with one end containing forked lugs to slip under the screw heads. There were some wire nuts for the other end to attach to the existing wiring, I think I just soldered and heat-shrinked those ends.