If you travel in winter or drive in snow, you'll have run into a limit of lithium: it can't be charged below 0°C without damage. What normally happens is the BMS cuts off charging in the cold to protect the battery, but that means that, in real cold, your battery stops recharging right when you need it most. That's what the self-heating lithium battery is for. Let's look at what it is and when it's worth it.
The problem: charging lithium in the cold
Charging a LiFePO4 battery below 0°C causes permanent damage to the cells (so-called "lithium plating"). That's why a good BMS automatically cuts off charging once the internal temperature drops below a safe threshold. It's a necessary protection, but in the depths of winter it can leave you unable to recharge from the alternator or the sun until the battery warms up. We explain this in temperature and batteries.
The solution: the self-heating battery
A self-heating lithium battery has a built-in system that warms the cells themselves when the temperature drops too low, using a small amount of energy. So, before accepting a charge in the cold, the battery warms itself up to a safe temperature and only then allows charging. In practice, it lets you recharge even in sub-zero outside temperatures.
When it's worth having
- If you travel in winter or drive in snow regularly, and need to recharge from the alternator or the sun in sub-zero temperatures.
- If you live in the camper in cold areas part of the year.
- If you keep the van outdoors in very cold climates and want to be able to use it without waiting around.
For three-season use (spring to autumn) in temperate climates, it usually isn't necessary: a BMS that protects the charge in cold weather is enough.
What to bear in mind
The heating system uses some energy and a self-heating battery costs more. It's a specific solution for genuinely cold conditions; if your use doesn't justify it, a normal battery with good cold-charge protection is enough. Also remember that in winter your runtime gets tighter because of less sunlight and higher consumption; size it properly in how much battery you need.
In short
A self-heating lithium battery warms itself up so it can charge in sub-zero cold, solving the cold-charge cutoff; it's worth having if you travel a lot in winter or snow. The step you can take today: if you use your camper heavily in winter and recharge in cold weather, consider a self-heating battery; if you travel in temperate climates, it's enough to make sure your battery protects the charge below 0°C.
