LiFePO4 batteries with heating offer you a big advantage. While batteries of this technology must not be charged at temperatures below 5°C, those with an integrated heating function can bring themselves into a state in which charging is permitted.
There are a few things to keep in mind, though. This article should help you understand the requirements and take all the necessary measures to make the best use of the benefits of your battery with integrated heating.
Allow for the Heat-Up Time
LiFePo4 batteries must not be charged when their temperature is below 5°C . LiFePO4 batteries with integrated heating solve this. They do not depend on you first warming the entire space around them enough for their core temperature to rise – they can heat themselves up so that they can be charged.
However, this only happens if enough charging power is available, meaning the charging current must first be sufficient for heating before charging even starts.
Depending on the type of battery and its current temperature, it takes a while until charging begins. With very short drives and a cold battery, it can therefore happen that no charging takes place at all, because the trip is over before enough heating has been achieved.
How long does heating take?
The heat-up time until charging is possible depends on the battery itself, its integrated heating function and, of course, the current temperature.
With our tigerexped LiFePo4 battery with 180W heating power it takes
- about 20 min (+/- 10 min) at 0° C.
- about 1.5h (+/-) at -35° C.
Charging Self-Heating Batteries with Solar in Winter
While battery heating consumes additional power, the energy yield from solar panels is significantly lower in winter than from spring to late summer.
Depending on the size of the solar system and the current weather conditions, the solar yield can be so low that it is not enough to run the heating and thus bring the battery into a chargeable state. If there is more than one battery in the system, the heating demand of course increases accordingly with the number of batteries.
If solar is the only charging source available in winter, the system must therefore be sized accordingly in advance. Charging with sufficient energy becomes at least more likely under such unfavorable conditions, although even a large system of course cannot generate power from absolutely unsuitable conditions.
Configuring the Charging Equipment for a Battery with Integrated Heating
For heating (and then charging) to start, the charging equipment must also be configured accordingly, in addition to providing enough energy.
Chargers in LiFePo mode often stop charging at temperatures that are too cold, because they assume the battery must not be charged under these circumstances. They do not “know” that the power provided is first used to bring the battery into a state in which charging is permitted.
Most chargers have a setting option for this.
With charging equipment from Victron Energy, for example, the low-temperature cut-off can easily be disabled in the settings via the app.
With Votronic it depends on the device. Here, the low-temperature cut-off cannot always be disabled in LiFePo4 mode. There is a solution, however, so that you can also charge with Votronic charge boosters at cold temperatures.
If you run into this problem, we are happy to help: technik@tigerexped.de
Conclusion on Running LiFePo4 Batteries with Heating in Winter
- It takes a certain amount of time until heating is complete. Until then, no current flows into the battery.
- If necessary, factor the heat-up time into your driving time.
- If solar is the only power source, the system must be sized large enough, because of the lower winter yields, to provide enough power for heating and charging.
- Chargers must be configured accordingly (low-temperature cut-off “Off”), so that the power supply to the battery (and thus to the heating) is not automatically stopped at low temperatures to protect the battery.
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