Hi,
Can anyone confirm from experience what is the lowest voltage, that is ok to use to power a D1 MINI ESP8266 via VIN/VCC pin?
On the official requirement it says Power Supply via VIN,VCC takes 4V to 6V
The problem is most battery power module like TP4056, doesn't have boost module. So output voltage is as high as battery voltage (or bit lower). Meaning with a 3.7v lithium cell, once battery is drained from its peak 4.2v, it might come down to even 3.5v.
Question is, is it safe to power D1 MINI via VIN/VCC pin (marked 5v on board !) with say 3.5v power?
Assuming all components in the system runs on 3.3v power/logic.
I was testing my system, and it was running ok on 3.9v. That is well below the minimum specified voltage (4v). Question is how low it can go? and how safe it is to do so?
There are a lot of devices called D1 Mini, post a link to the one you are referencing. Also make a note of the ESP part number suffix (last letter in number). Some may have regulations on board some do not.
Without more technical information I have to say stay with in the published specifications. They publish them for a reason. Setting the voltage to high will damage the CPU. Setting the voltage to low will not normally damage the CPU however: As the voltage goes down so does the switching speed of the internal FETs. As this happens the instructions start to fail generally starting with the more complex ones, results are unknown. These are the instructions that the compiler generates for the CPU not the code you write unless it is in assembler. These specifications are to guarantee it will work over its rated environment, exceeding these can destroy the unit. All electronic parts have tolerances and they can stack up to benefit or hurt you, depends. The best way to get this answered correctly is to contact the sales agent or manufacturer and pose the question to them.
Of course its best to stay within published specification. but i failed to see the practicality of whole thing. Considering this is ultra portable module, it should be able to powered up from a battery. But how? As per the specification 5v pin takes 4v to 6v and 3.3v pin takes 2.58v to 3.6v. While a lithium cell battery outputs .3.5v to 4.2v. Hence its unsafe to connect to 3.3v pin as battery voltage can be higher than 3.6v. And unsafe to connect to 5v pin as battery voltage can be lower than 4v.
One might think that's what battery charger modules are for, but no. most of the available battery charger module doesn't have a built in booster. Meaning it only provide maximum voltage battery can provide. So back to problem one.
I tried charger module HT4928S, 134N3P and TP4056 all provide maximum voltage as the connected battery.
I also tried this
that does have a built in boost module. but its bulky and wasteful as it generate heat. but most importantly lowest adjustable output voltage is 5.6v not 4.3 as claimed by the specification. thats bit on the high side for a D1 MINI, though within rage.
I can't be the only one with this problem. that's why i was wondering hows people dealing with this issue.
Most of the D1 Mini battery/solar powered projects i see online is using a regular TP4056 without the boost. so i thought maybe its ok to power the module with much lower voltage than specified. but unfortunately i see not much response from the community to confirm that either
At this point the only suggestion I can make is do some research on basic electronics. Based on your logic I could operate my house on a watch battery for a year because I do not understand why not. Engineering is not a put the blocks together, it is a lot of compromises and trade offs, the engineer decides what can be done in the price range needed. He then uses blocks that will do what he needs or designs them.
Thanks for a on topic reply, finally! I was almost loosing the faith. lol
Yes adding a separate step up regulator on top of the charging module is looks like the best solution so far.
Though if we need to use two modules (charger module + regulator module) to hook up a battery to a tiny on inch board, its looks far from pretty.
i did find one more small footprint charger module that has built in boost regulator. its by MakerFocus.
It looks awesome, though few comments says its cuts off power once ESP8266 goes to deep sleep. and never woke up. wondering if anybody had used those MakerFocus charge module with deep sleep with node module /D1 Mini.