Lifepo4 batteries are 3.2v and rechargeable.
https://www.bunnings.com.au/solar-magic-lithium-14500-3-2v-rechargeable-battery-2-pack_p4351891
https://www.jaycar.com.au/18650-lifepo4-battery-1600mah-3-2v/p/SB2307
AU$6.01 64%OFF | 10Pcs 18650 Battery Holder
https://a.aliexpress.com/_mLQ2jR0
The upside with LiFePO4 is the voltage-discharge curve is very flat between 5% and 95% state of charge.
The downside of this is voltage as a proxy for battery state of charge is not valid. Without a shunt measuring energy in/out you will really only know when the battery is fully charged or all but fully discharged.
As with all lithium chemistry, it’s really important to use a charger specific for that chemistry, or at least a fixed voltage controllable power supply. Very easy to destroy them with too high a voltage.
With LiFePO4 it’ll just kill the battery, might release some nasty chemicals. Max 3.65 V (and 3.45 V will be plenty as a charge voltage, that’ll get a cell to ~98%).
With NMC the risk is fire/explosion. I would avoid this chemistry unless you have a way to safely charge them. Commercial units typically have in-built BMS with protections for over charge/discharge. When using raw cells take great care.
With discharge you need a way to cut the circuit once voltages drops below a safe level for the battery as further discharge will damage the cell.
I’ve been happy with my LittoKala charger so far. Seems to do what it says on the tin.
Liitokala Lii-500 Lii-402 Lii-202
https://a.aliexpress.com/_mLOvjOW
I thought Lifepo4 was more forgiving in this regard, but have done limited reading on the topic.
I’ve been using a few of these for 18+ months and have never missed a beat and have worked great on rechargeable AAA if you decide to not go the hardwired route.
LiFePO4 are forgiving of being discharged to manufacturer’s 0% state of charge (defined as the capacity in the range 2.5 V to 3.65 V) but that is not the absolute lowest voltage the cell can be discharged to.
Once you allow it to go below 2.5 V then there is a strong likelihood of permanent cell damage. They will keep going if you let them, hence having a battery protection system to prevent further discharge.
Best to keep it no lower than 3.0 V, that’s like at 1-2% SOC anyway. The charge and discharge curves are very flat in the normal operating range, but at each end (fully charged and fully discharged) the voltage changes rapidly and a battery protection system is needed as you can go from OK to bad news pretty quickly.
Note:
How little charge the cell has if only charged to 3.3 V (or less)
How much more charge the cell has if charged to 3.4 V
How very little extra capacity there is if charged higher than 3.4 V (don’t charge to 4.2 V!)
How steep the drop off if once you reach 3.0 V.
To save cluttering up this topic I am detailing my blind control progress here:
Hi, I wonder if you may be able to give a little more detail on how to use the tuya-cli and where the configuration.yaml file you mentioned is located assuming this is not the main configuration.yaml in the /homeassistant folder.
Hey folks! I just got my first EV. Currently just running off the 10A socket in my garage, but wanting to get an electrician out to do a bunch of work, so looking at getting a 15A socket installed on a separate circuit. I do not need a dedicated wall charger as my PV array is only 5kW and I work from home so have little use for fast charging - would just be nice to get more than the 8A I can currently safely pull.
Has anyone had any success with a device that has power monitoring and a relay that is strong enough to break 15A current? It seems the general consensus is to get the Shelley EM and use the contractor control to control another relay/breaker. Is this what I should be looking to do?
Secondly, I would love to replace my dumb Fluro light in the garage with a smart light. I don’t know of many/any reliable drop in tube replacements, but am not against replacing the entire assembly. If that were the case, what would be the recommendation for lights strong enough for the larger space of a garage? Or does anyone know of any reliable tube replacements?
Legally the 15A does need to be on it’s own circuit, so that is correct.
Either that or one of these if you are already into Z-Wave.
I’d go with replacing it with a normal dumb LED light(s) and install a smart switch instead.
Great tips thanks! The Aeotec looks good, however I’m purely WiFi/Zigbee so may have to go with the Shelley + a separate relay.
Just get a z-wave stick like the Zooz 800 Series Z-Wave Long Range S2 Stick (ZST39 LR) so that you have options to integrate devices that are not wifi/zigbee avaliable.
Most of these small/compact smart switching devices are not really rated for handling the switching of higher currents nor the higher sustained current. Many of them might say they are rated at “16A” but in reality that’s for short duration peak load, not sustained and not for regular switching at that full load.
So yes, get a decent contactor properly rated for the job, controlled by a smart switch of your choice - the Shelly is perfectly fine for that job but there are others.
It’s a requirement to have a dedicated circuit for a 15 A power outlet in any case.
Pretty sure the 40A rated Aeotec would be good for 16A though…(It’s a much more compact solution too)
I’ve had great success with Aeotec over the years. Some of my Aeotec devices are a good 7+ years old.
Definitely, that’s an exception though when you consider the smart switches people generally consider.
If going to the trouble to install a new circuit in the MCB and run a new cable to the garage and then add one of those switches and the hub, I reckon you may as well put in a 32 A circuit and cable.
With some help I just managed to integrate my EV with Home Assistant. So I could control charging that way:
I won’t be as I already use an OCPP EVSE and that controls charging based on various control options be it from solar PV/avoiding grid imports, or taking advantage of free tariff periods.
EDIT: Added a better image of MG4 charge controls in Home Assistant
Is there something similar that is wifi-based? I dont use Z wave at all at this point.
Not that I’ve seen.
hey i got mine going! set it up using shelly app but it doesn’t seem to appear under integrations. i can add it through shelly integration in home assistant but not sure if that is right approach?
thank you
here it is in ha using shelly
I can make it show as a door but it seems to be reversed. am able to update it in shelly app settings and it shows correctly now. i hope i can uninstall shelly app now.
Anyway is this the right way to use this in home assisant?
That’s the correct approach when setting items up, you add them through the intergration that they use in home assistant, just change the name to a better identifiable name and then you can setup your automatons that you need with it.
I literally got it up and running in like five minutes. And this one device can let me reach four contact sensors.
So good
It’s acting as an extender for those that are being detected through it which is how you extend out your devices to where you need to use them the most, you use device types that act as routers for the end point ones to connect through.
In this case since your shelly i4 is using an ESP32 its also acting as a bluetooth proxy through the wifi.
