Ok hold on...you just said not to do rechargeable...no?
I use the IKEA 2450 mAh āLADDAā AA rechargeables. In my August lock under heavy use, they last about three months before I have the charge them again. The Yale so far seems to be doing well on the alkalines that came with it, so Iām hopeful Iāll get a bit longer from the NiMH batteries in it. But even if I have to charge it in the same schedule, not a big deal.
I do not personally recommend rechargeable lithium batteries. The link I posted is for Nickel Metal Hydride batteries. Totally different technology and performance characteristics.
Here's something I found about a "raceway" and wiring through a door.
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And that Hinge is discounted to only $169
You can modify a door hinge to pass the wires through. Just use rubber grommets where the wires and metal come into contact. This is an interesting concept and to use a raceway. Hmmm going to noodle this a bit more and then might have to act on it. I really do not want my doors rely on batteries to lock/unlock. It seems that with the Kwikset locks if they go below 70% they become unreliable to HE on sending their current lock/unlock state. By running low voltage wiring to the device and soldering directly to the negative/positive leads in the battery container I could eliminate batteries completely. I have to figure out what voltage my doors need as I may just invest in a 5v power supply that will provide power to both doors in my basement ceiling.
I thought a lot about these scenarios with my Okidokeys lock. I was going to use some other device to trigger it since its app was discontinued. But in the end I decided I didnāt want to ruin the integrity of the door with a channel of any kind. If you donāt care about this kind of thing, then you could use a router and a very narrow bit with a guide and run a very shallow channel along the edge of the door, then seal it with an acrylic caulking.
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Yeah I saw that.. did find a cheaper one for only $89...
4 AA batteries are nominally 6v. Delivering 5v would put it at that 80% and may not account for cable loss.
I'd probably design it to have 12v on the wire and then find someone to 3D print out some fake-batteries and put a small voltage regulator inside the first of the 4 fake-battery. The other 3 would be wired as a "short" to just chain the voltage along to the final battery slot.
These are dummy batteries with connect through - you'd just have to wire the start of the first and end of the last..
I'm assuming longer wire runs, small wires = loss of voltage. Power supply might be close to one door, but a LONG way from the second.
I use NiMH batteries in place of Alkaline for all my devices. I've been thinking of soldering a small charging cable onto my Kwikset locks battery tray and using a NiMH charger such as this to charge them every few months:
I've also considered just hooking them up to a constant 5.6 v power supply to keep the batteries from discharging below 1.4v (IE: float charge them at around 70% of capacity). You can't float charge NiMH to 100% because it has a voltage dip once it gets above 70% and it will enter thermal runaway and ruin the cells. As long as you stay below 1.45v/cell though you shouldn't have to worry about that. But then I'd need to find a way to hide the wires somewhere since they'd be hooked up 24/7 and drilling a hole through the door is probably more than I'm willing to take on project wise.
Wouldn't it have been nice if they just put a small micro USB or USB C port on these locks that you could just plug them in a few hours every year or so to keep them charged? NiMH charging circuitry is so tiny they can literally embed it into the USB casing of the device I linked to above, and it's relatively inexpensive.
Since thereās a good chance a charge cable could be in advertently ripped from the lock when opening the door, a magnetic charge port would be ideal. Of course, if we want lock manufactures to make these changes, we need to give them our ideas
How about spring loaded contacts on the jam side, supplying the voltage, and flush mounted mating contacts on the door edge just above or below the lock. When the doorās closed, thereās power going to the lock. That should work fine since you donāt need to power a lock when the door is open.
Alternately, this method could be used to keep the charge of rechargeable batteries topped up.
[Edit] Now that I think about it, probably not a good idea to constantly apply and remove all power to the lock. So I think itās still a feasible idea, but best for keeping batteries topped up
That is how my Jeep works for the tailgate. Contacts allow the rear third brake light to work when the door is closed. Thought about this option too.
So here is another question surrounding the high NiHM battery options: how long do they really last? Both doors are heavy traffic especially the garage door as we go in/out to garage Freezer and fridge multiple times a day. One option I thought about is changing how I handle auto-locking for at least the garage door. Reducing or eliminating the auto lock while people are in the house during a certain time of day/modes. Wifey didnāt like this option as she wants the house always locked up and entry only to occur either through manual entry or approved code entry.
So thatās off the table 
Thereās no way to know how long theyāre going to last until you try. Itās going to vary for every single lock manufacturer and battery manufacturer and type, and just about every model within a lock manufacturerās lineup
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I like the ideas being presented overall. So just to recap:
- Use high powered NiHM batteries for best overall performance and potential longevity compared to alkaline.
- Avoid recharable NiHM batteries if possible unless you can get into a schedule to replace frequently with charged batteries
- (4) AA batteries is really 6.4v. If hardwiring I will need to take into account there isnāt a 6.4v power supply and will need to invest in a 10v power supply with a step down module (probably custom made) to 6.4v at the door lock end of the wire.
My last option may be to invest in Yale locks as I continue to have connectivity drops due to the locks either antenna or power save mode when batteries get below 70%.
Any others?
Oh man... so many variables. If it's a high traffic door: Probably twice as long as Alkaline. if it's a rarely used door: Probably less than Alkaline.
The key is to use high capacity "pre-charged" NiMH cells. Standard NiMH has a fairly high "self discharge" rate which means that even if you keep them in the package and never use them their internal self discharge will cause them to go flat after 6 months. the "pre-charged" NiMH cells will hold their charge for 3+ years. In fact I had a Kwikset 911 (Not zwave, just a basic keypad only) lock before upgrading to the Kwikset 914, and that Kwikset 911 lasted over 3 years on a single charge of NiMH batteries.
The biggest thing with NiMH is understanding the differences in the discharge voltage curve. I've switched every device I own that uses Alkaline batteries toi NiMH so far and have been happy in all cases. The only exception so far is the Kwikset 914's that I just installed a month ago: They still have the alkaline batteries they came with. I figured I might as well use them since there's no sense in throwing away good batteries.
So keep in mind I haven't actually tested the battery performance in these Zwave Kwikset 914 locks yet: But in general in high demand situations NiMH will outlast Alkaline significantly. In low drain situations Alkaline will sometimes last a little longer due to it's almost zero self discharge rate. I find most use cases tend to favor NiMH performance over alkaline. The biggest issue is the battery level reporting will not be accurate because of the difference in discharge voltage curves for the two cells:
I've tested NiMH in a variety of other devices and found that it has a much "flatter" discharge curve than Alkaline and this is what makes reporting battery levels difficult for devices calibrated to an Alkaline discharge curve. An Alkaline battery voltage drops off very quickly. They are rated at 1.5v brand new out of the box: but as soon as you start using them they drop off very fast. NiMH also starts at close to 1.5v when fresh off the charger and almost instantly drops to 1.2v... But then stays there until nearly depleted:
In fact for many use cases (especially high drain) a quality NiMH will actually last longer than an Alkaline and are easier on motors because they hold their voltage under load better.
In my experience most devices that are calibrated to report battery level for Alkaline all offer similar differences in behavior when given NiMH batteries instead: They report an almost immediate drop in battery level to 60% (Because the cells drop to 1.2v so quickly) and then stay there for months. They will then slowly tick down through 30% or so and then drop off a cliff after that. So for each device I want to switch from Alkaline to NiMH I just monitor it and see where that 'cliff" is for that particular device since every device has a different cut-off voltage. A lot of Alkaline devices will cut off at very low voltages such as 0.8v and so for a device like that you may never "see" it hit 20% because the NiMH is completely flat before it drops to 0.8 volts where-as an Alakline still has some life left at 0.8 volts.
In general I find that if you can remember that:
60% Alkaline level = 100% NiMH level
and
20% Alkaline level = 0% NiMH level
This makes it easier to understand the battery levels and not to freak out when you see the battery level drop quickly to 60%. It's just a matter of understanding the calibration. Just aim to change/recharge them around 30% and you'll usually be fine.
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Did someone else say something in another thread about Yale locks? Iām just saying that mine is doing good so far, but I havenāt had it that long and my batteries are at 97%. I have no idea how itās going to behave when it gets to 70% or below. I havenāt gotten there yet
