Heating Mat for battery warming - thoughts / recommendations ?

[SporranMcDonald]

The Pylontechs are in the Attic.

I have build an ad-hoc polystyrene box around them, but need a trickle heat source to keep them > 10degC.

At present I have two remote thermometer sensors within the box (1) at bottom (2nd) at top.
- The lower one dropped to 7 deg C yesterday overnight.
- The higher one is 2 - 4 deg C higher.

What experiences / recommendations ? Inkbird ? Generic heat mat ?

It would be good if I could control the wattage as well as set the ON-temp & OFF-temp . . .

Thx

[MrPablo]

I'd also be interested in this as well.
Current thinking is a brute force temporary method using a small tube heater in the nearby area - long-term is an insulated enclosure with something lower power.

[AGT]

Trace heating tape is low wattage

What about a 15 watt light bulb?

[AGT]

What do pylontech actually say in their specification regarding operating temperatures?

[Stinsy]

First step is to confirm you actually have a problem! Pylontech throttle the charge rate from 10A/kWh to 2A/kWh when the cell temperature drops below 0℃. Be aware that this is the cell temp not the ambient temp, the cells take a long time to cool down when not in use and quickly warm up again when charged at the lower rate.

My Pylontechs are in the attic and last year it got down to -6℃ and I didn’t once notice the charge-rate be throttled due to temperature. I’ve had this in the past though, I can see them charge at 1.2kW for 20mins or so before cranking to full whack.

[SporranMcDonald]

Thanks AGT & Stinsy.

Plenty of time to observe and evaluate before panicking into overkill.

Pylontech manual gives limited info :-
- Charging window : Lower limit 0 C
- Discharge window : Lower Limit -10 C

Stinsy's description is rather more useful.

[SporranMcDonald]

I've just got hold of a 230V 13W heating pad to put under the bottom Pylontech ( 4 * 2000c in the stack ).

I was going to control the heating pad with a Temperature Sensor Relay ( a W1209 ).

However, with the batteries in the attic and Remote temp Sensors already in the insulated box I thought it would be better to experiment with manual control of the Heating Pad first.

I guess I need a WiFi controlled plug to switch the pad ON/OFF. . . . . to avoid climbing up/down to attic each time.

Is this as simple as it sounds ? My first WiFi plug . . . are they cheap / readily available / reliable / easy-to-use .
Is there anything a newbie user need watch out for ??
Linux on the PC
Android on the Phone.

Thanks.

[AGT]

I use Tapo p110 Wi-Fi sockets, they have energy monitoring built in too, set schedules for on/off times, very easy to set up and control.

[SporranMcDonald]

I have upgraded from manual monitoring : -
PREVIOUSLY : I (remotely) read a temperature Sensor near the Batteries (attic) and I switch the WiFi socket ( with connected heating elements ), On/Off

Now :-
Raspberry Pi Zero 2W - runs a Python program to switch ON the heating elements if coldest cell temp is <= 10 C
- monitors the "Lowest Battery Temperature" directly from the Pylontech Master Battery BMS
- switches the heating elements On/Off for 15-minute blocks

This is pretty elementary stuff for most of you here. But I have learnt a huge amount by DIY-ing it.

[Fintray]

Good to hear that you have managed to automate it and learned something new in the process.