ESP32 on Batteries - your setup

[meneldor]

Have anyone tried SP6205EM5-L-3-3 or MCP1726-3302E/SN?

[rontec]

Have anyone tried SP6205EM5-L-3-3 or MCP1726-3302E/SN?

Consider these switching regulators, instead of linear regulators, instead:

The EA3036C is under $0.15 per unit
The MP2161 is under $0.10 per unit
The SY8089 is under $0.09 per unit

Also see https://www.esp32.com/viewtopic.php?f=12&t=8451

[tvoneicken]

I haven't looked these switching regulators up, but in general their quiescent current is higher than that of linear regulators and if you're regulating down from a LiPo the voltage drop isn't all that big, thus LDO has little/no performance disadvantage when the esp32 is active but a big advantage (for LDO) when idle.

[rontec]

[deleted]

[tvoneicken]

LiPo = Lithium Polymer, basically same chemistry as Li-Ion and 4.2V charge, so quite a bit out of spec. An esp32 won't instantaneously combust at 4.2V, but that's past my comfort zone... LiFePO4 is a different checmistry and charges to 3.6V, so OK, but capacity is quite a bit lower for the same volume and there are very few choices for small cells.

[rontec]

I did get the chemistries mixed up for a moment.

The MP2161 has IQ of 17μA.

That seems to be a much smaller issue than throwing away 0.16W (3.7V to 3.3V at 400 mA at full load) from a linear regulator.

In the end, whether you want a regulator that operators most efficiently at low load or high load depends on the expected sleep/wake cycles of your design.

[woofy!]

Hi Guys,

Just an update on the oil tank level monitor mentioned in an earlier post. The batteries have finally expired, they are now down from 4.5v to 3.8v and the sonar I'm using for depth sensing no longer works although it is still transmitting telemetry every hour.

So that's an ESP32 + sensors running almost 16 months on 3 * AA batteries.
Not too bad at all.

[daisy1980]

@woofy, can you post detail on your project ? Type of dev / board you are using, component list etc. Appreciate it.

[woofy!]

Here's the schematic and pcb. I'll try to find the firmware when I get home tonight.

[commando_j]

You have the option for ultra-low quiescent current buck-boost regulators if you can deal with BGA packages.

Or something like this LTC3443 if money is no object.
http://www.farnell.com/datasheets/43210.pdf

It's hard to find a buck-boost that is cheap, easy package to solder, decent current (600mA+), and low quiescent current (<30uA). There is a bit of sacrifice on at least one of those requirements, at least in my quick search.