Additional Charger Hardware Controls (V3.8.4) - OVMS User Manual

OVMS: Renault Twizy User Guide

Additional Charger Hardware Controls (V3.8.4)

Since version 3.8.4 the OVMS can control an additional charger fan and an additional charger.
Add-on Fan
The Elips 2000W charger officially specified operation range is -20..+50 °C. This is exceeded by
the Twizy easily even on moderate days. The charger temperature can easily rise above 60 °C, and
this is possibly the main reason why Twizy chargers eventually die.
A counter measure can be to add an additional fan and switch that fan on as necessary. This can be
done using the OVMS output port RB1, which is available at the expansion port on pin 18. (Note:
CMOS signal level, low power, use a relay module or power transistor to actually provide power to
the fan!)
The OVMS monitors the charger temperature. It turns on RB1 (+5V) when the charger temperature
rises above 45 °C, and off when the temperature drops below 45 °C. After end of charge (Twizy
system switched off), the OVMS does not get temperature updates, so it keeps the fan running for 5
minutes.
The fan control works during charging and driving, as during driving the charger also has to supply
+12V by the builtin DC/DC converter, and a drive may start with a hot charger.
Add-on Charger
The Elips 2000W (as the name says) does only charge with ~2 kW, thus needing 3-3.5 hours to
charge the original Twizy battery. That's quite slow and gets worse when replacing the battery by a
larger one.
The Elips is running a special Renault firmware and also taking a crucial role in the Twizy system
communication, for example to control the BMS. So it's not easily replaced by a third party charger.
But a third party charger can run in parallel to the Elips to boost the charge power. This can be done
best from the „rear end", i.e. using the battery main connector as the power input (like the SEVCON
does during regenerative braking).
Some documented examples of additional chargers:
https://www.twizy-forum.de/werkstatt-twizy/84935-twizy-schnelllader
•
https://www.twizy-forum.de/projekte-twizy/83603-schnell-lader-extern
•
https://www.twizy-forum.de/tipps-und-tricks-twizy/80814-twizy-schnellladen-die-wave-
•
kann-kommen
To avoid damaging the battery, additional charge power should not be supplied when the battery is
nearly full.
The OVMS provides a signal on port RB4 (expansion port pin 15, CMOS signal) to automatically
turn an additional charger on and off:
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2019/05/02 RT3.9.1