WeatherDuino Forum

Today I made some successful and simple modifications to my WeatherDuino 4Pro Wireless Display.

I wanted a way to move my Wireless display unit form one room to the next, without needing to turn the system off and have it reload each time. I looked at adding two simple Arduino components - the "Lithium Battery USB Charger Module" and "5V DC to DC Converter Module".

[attachment=1429] [attachment=1428]
Lithium Battery Charger and DC to DC Voltage Controller


With the addition of an "18650 Lithium 3.7V 2,600mAh" battery, I have portable and rechargeable power source for this wireless display unit.

Simply adding the positive and negative wire from the "5V DC to DC Converter Module" to the positive and negative terminals on the "ESP8266 Main Board".

I took some current readings too of the Wireless display unit. It has a constant draw of 90mA with peak draw around 160mA. With a battery capacity of 2,600mAh, there is a potential of 16+ hours of battery standby time; truly enough to get through the night with.

A 10K ohm potentiometer has also been added across the backlight jumpers so the display can be dimmed - ideal for a bedroom. This also saves on the power consumption and drops the constant 90mA draw down to 50mA when dimmed fully.

Next task - housing it all in a nice enclosure.

[attachment=1426] [attachment=1427]

That is excellent! Well done 

Fantastic idea Palmy!

And here is a portable Wireless Display. Amazing.

Those who like to build things, always find something to improve! Interesting modification, good job.
Thank you for sharing.

For those who want to do the interesting modification suggested by Palmyweather and turn the Wireless Display in a portable unit, this little module which cost less than 3€ on eBay will make doing it even easier:









Two modules are now travelling to my home.
Seller link: https://www.ebay.com/itm/5V-UPS-Power-Di...SwkthZpysW

Thanks for the great idea, Palmyweather, and thank you for the link, Werk_AG. I've just ordered two of those and also the "over-discharge protection boards". This will be very useful for other things as well as the WD!!

Allan.

Hello,

since my profession is testing mainly Li-Ion batteries I would like to remind you that the usage of those batteries can be very dangerous under certain circumstances.
Due to misuse or productions failures a thermal runaway situation can occur, causing at least smoke or even fire.

So in the best case you have in addition to the charging IC a separate surveillance IC for over- and undervoltage, as well as overcurrent and overtemperature.

This are some crucial points what ISO62133 demands for portable Li-Ion Batteries.

And please don't buy some cheap cells, as they won't have the rated capacity and there is some danger of bad production.

Regards,
engolling

Hi Engolling,

Advices are always welcome, and in the case of Li-Ion batteries even more.

The module I posted above is using the LTC4056 chip (perhaps fake) and according to specs seems it includes some of the protections mentioned by you.

Quote:The output driver is both current limited and thermally
protected to prevent operating outside of safe limits. No
external blocking diode or sense resistor is required. The
LTC4056 also includes low battery charge conditioning
(trickle charging), undervoltage charge current limiting,
automatic recharge and a charge status output.

I'm in no way an expert in this matter, so what you think about that specific module?

Hello Werk,

the IC is good for a controlled charging of a Li-Ion Cell. 
But it does not provide a overtemperature and overcurrent protection of the cell, it only protects itself.

So I would recommend at least an extra safety module, search for: battery protection board 1s
If you want to be very safe get a module with temperature sensor or add a thermo fuse attached to the cell.

This should give you 3 stages of safety (which is not to much in my opinion since a 18650 cell in thermal runaway can generate a red glowing metal housing, called can shooting through the air):
1. The cell itself - if it is correctly manufactured it should irreversibly protect itself against overcharging, shortcircuit and overtemperature with a built in circuit interruption device (CID)
2. The charger - protects against overcharging
3. The safety circuit - protects against overcharging, short circuit and overcurrent and maybe against overtemperature.

Since it can happen, that one stage fails, you should have a backup.

If you have further questions about failing mechanisms of Li-Ion batteries or international standards feel free to contact me.

engolling

Hello,

I've prepared nearly the same as Palmyweather in the beginning ot this thread
and use nearly the same modules as him as subsequently described by Werk_AG 

But in the latter is not a module that Palmyweather used in his design - I used a little
diferent, but in its function and integrated circuit installation the same. Its advantage lies
primarily in battery protection:

[Image: DD05plusDD04_sm.jpg]

And here is the final build of my Wireless Display:

[Image: DSC_3261-upr_sm.jpg] [Image: DSC_3262-upr_sm.jpg]

[Image: DSC_3263-upr_sm.jpg] 

It continues ...