My battery backup solution

So I am putting up several Wyze cams outdoors to watch my external entrances to my home. There are good solutions on Amazon for the cam, sd card, enclosure, and power cable. The one pain point for me was that there’s no way to prevent someone from simply unplugging the camera, short of running a new circuit into my soffits and installing electrical outlets out of reach of the bad guys.

Yes, you can find a few commercial cell phone charger packs that do pass through charging, but they are all relatively expensive (in comparison to the rest of the camera gear), and most are far too bulky to a discreet install. I decided to roll the dice and try making my own.

I ordered some small PCB boards off of Amazon. Don’t let this part intimidate you. All you need to know is the approximate discharge rate and that the board will allow pass through charging for this project. Here’s what I went with.

You’ll also need a battery holder. Here’s mine.

I am using 18650 batteries because I had some kicking around from an aborted e-bike project last year. If you want to do the same, look around for a discarded laptop battery pack. What I found is that out of the six to nine cells in a pack, one or two would have failed, bringing the voltage of the pack down to where it wouldn’t run a laptop anymore. Take the pack apart and separate the cells, charge the ones that will charge and they were very usable. If you prefer, you can buy 18650 cells for around $6-$7 each new.

Putting things together is very, very easy. All you have to do is solder the positive and negative wires from the battery holder to the B+ and B- contact points on the PCB board, install a battery, and plug it in. The micro USB is your AC power, the standard usb is your output.

The whole package is about the size of a large bic lighter and should run a Wyze for about an hour of continuous record time. More than enough for my purposes. If you want more capacity, you simply build a bigger pack at the same voltage by linking more battery cells together.

Cost for the project is about $4.50 US per pack, or around $10 US if you buy a new battery.

I’m still working on a waterproof enclosure. Two of mine are well protected by soffit, so it won’t matter, but the third is pretty exposed. Right now I am thinking about 1 1/4" clear aquarium tubing pulled over the whole pack, cutouts for the USB connectors, then install cables and silicone the cables into place. Then close both ends of the tubing with heat. If you have another idea, throw it out there!


That’s actually neat. What is the true lasting power on cam when power disconnected. Have you experimented?

I will be mounting them tomorrow, so no field data as of yet. Wyze says full power draw on the cam is 700 milliamps. Using a nominal batter voltage of 3.9v and 1700 mah measured on my battery, my calculator says just over an hour of continuous run time at full power. Probably pretty close in my case since I use an SD card to record continuously.

If you want more run time, you just have to connect more than one battery holder in parallel to get whatever capacity you are looking for. In my case, I’m really just trying to keep someone from disconnecting the too available AC plug and disabling the camera.

So the first test run this evening. The camera ran for 3hrs 40mins on battery alone.

Not bad for a ten dollar hack.

After considering the weatherproofing problem more, I think I’m gonna use heat shrink to wrap the whole thing, then silicone the cables into place.


Great project, thanks.
How did you determine that the board was going to provide pass-through power? I don’t see that in the description, doesn’t mean that it isn’t there. :slight_smile:
I can’t get that exact board on Amazon Canada but there are alternatives that would ship from China.

Given the $3.59 for the board, $5.49 for the holder and your $6-7 for a 18650 at 3000mAh plus shipping if you don’t up the order to $25, we’re looking at a Jefferson or so for your solution.

Checking for “portable cell phone power banks” on teh amuhzon with the $10-25 filter, you can get a quality Anker 6700mAh bank for $23.99.

For about the same, there are banks up to 24000mAh if you’re OK dealing with global sellers; specs might be, um, exaggerated. For those sellers, there are a few two 18650 cell banks for ten bucks. However, RAVPower is quite reputable and they have a 26800mAh bank for $19.00. I have several of their products.

Research or seller inquiry will help in pass through determination, but Anker and RAVPower provide it mostly; one might double check on their web sites before a purchase.

BTW, for my dash cam, eliminating the pain of hard wiring it or the unsightly “hang/dangle the wire” strategy, I have a RAVPower 12000mAh bank in a sun visor organizer. And a 10-foot USB cable to reach the lighter socket adapter for the occasional 6-8 hour trips where it might need a pass through top-off.


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The holders were a 3 pack. You’re right, I didn’t include the cost of shipping. I’ve been a prime customer for many years and tend to forget about shipping costs.

The lowest price pass through battery bank I could find was $27. The home brewed pack cost me just over $4, or $10 if you have to buy a battery as well.

The bigger issue though is size. These cameras hang under the eaves of my house. Putting a battery pack the size of a paperback up there is unsightly and makes it obvious the camera has an alternate power source.

So I guess this is cheating somewhat, but I’ve found these mini-UPSes quite good:

TalentCell Rechargeable 12V 6000mAh/5V 12000mAh DC Output Lithium ion Battery Pack for LED Strip and CCTV Camera, Portable Li-ion Power Bank with Charger, Black

I’ve found ways to use these as utility power extenders as well. Here’s one I attached within my parents’ carport, up & out of reach, using strong adhesive velcro…

If it meets your needs, it’s not cheating. Thanks for giving folks another option.

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Batteries make great electric noise filters. We receive about 50 power bumps for every power outage. Those bumps generate a lot of electrical noise. A small battery pack would do a nice job to protect the camera and its settings. It sounds like a small “micro” UPS would be a great device for the rural user who has electrical power flickers at home.

One question: I see you are using just one battery cell on a two battery cell charger board. The add says 5 VDC input? How about this board it is setup for one battey and it has output protection or a BMS (battery management system included).
Dual Micro-USB 3.7v to 5V 2A Mobile Power Bank DIY 18650 Lithium

Great question. To be honest, when I read the spec I assumed “up to” 5v. Since 18650 cells run from 3.7v to 4.7v, I thought it was a good fit. Time will tell, I guess.

I plan to pull the batter after 40 days of use and test the voltage and max mah. I’ve got them written down on the battery from when I put the pack together. That should give me some idea of the longevity of this solution.

The reward for good work is…more work.

The 5V DC input isn’t related to the number of cells used.
5V DC is the voltage coming in to the micro USB port to charge the battery.
I don’t get where you are seeing that one board is designed for single cell and one is designed for multiple. They are designed to use multiple cells connected in parallel, up to 2 amps.

I don’t see how we determine if these boards will charge the battery and send power to the USB ports at the same time.

If I am totally off topic please forgive me. I’m hungry. :smile:


I could be wrong, but the way I read the spec and the way it seems to work is 5v 2a charge, and up to 5v 1a discharge. Using multiple batteries would mean connecting them parallel to give you greater mah while still staying undre the 5v discharge.

Lithium Ion batteries don’t accept being overcharged. The mechanical stress becomes an issues and this stress drastically shortens the life of the battery. They can also overheat and that can become a fire hazard. The maximum voltage for the 18650 is 4.2VDC. The link to the TooGoo? brand does describe the BMS circuits to protect the battery, the other board may have the same stuff. I will take a look and see. pause, looking, looking.
I would say the charger you selected is for single cell voltage and there must be electronic circuitry to protect the battery from overcharging. It should work.

  1. Aesthetics. i worry something like this will look terribly gaudy on the outside of my house. Most HOA’s would end up fining someone for this
  2. insurance/safety. Lithium ion batteries are bombs. If they are damaged, the can and will explode or catch fire. It’s bad enough we carry these things in our pockets all day but I definitely don’t want a bunch all over the outside of my house when I’m not there!

i’d recommend poe to usb5v adapters and a poe network switch. One switch in your basement can power (and monitor) up to 48 wyze cams. Put that network switch on a (UL Listed) UPS that is much less likely to burst into flames. UPSes can last DAYS if they are only powering a network switch. And when it comes time to replace batteries¸you only have to do it in one spot.

The fewer batteries in my life the better. Or at least, the fewer separate places there are that have batteries the better. my UPS is in a fairly safe place if it were to catch fire. Concrete floor and walls, and no combustible material nearby. As opposed to my wood based home exterior. Yikes!

Poe might cost a little more but fewer overall batteries is my preference.


Lithium ion batteries are not bombs. As I said earlier in this thread, that stereotype comes from cheap Chinese knockoff batteries. Don’t buy a battery that is a third the price of a name brand one and you won’t have any problem.

As for esthetics, that’s exactly why I built mine rather than trying to use a commercial pack. Mine look like a bulge in the power line. Commercial ones approach the size of a paperback book by the time you get something that will support power pass through.

If your HOA is that restrictive, I suggest moving. Sorry, I don’t need anyone that far into my business. I will take my money somewhere the word privacy still has meaning.

The reward for good work is…more work.

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Ravpower 6700ma
Be sure to use a 2a plug not the wyze 1a plug adapter.

I actually tried powerpacks like these initially, but I found that they didn’t load switch to battery power (like a UPS) during an interruption of AC utility power. This would cause my cam pans to either reboot or become inaccessible. I even tried daisy-chaining 2 or more with same results.

Curious to know your experience with this model when u unplug the charger cable to simulate powerfail?


That’s why I finally built my own. Most commercial pack I tried would change power state when 120v power was interrupted. Honestly, these boards just aren’t smart enough to do that. They provide power right through interruption of utility power.

The reward for good work is…more work.