Why a Lithium RV Battery Will Not Charge Below 5 °C, and What That Means for Winter Trips
Summary
Victron's technical data for both its Lithium Smart and Lithium NG 12.8 V batteries gives two temperature windows: discharge from −20 °C to +50 °C, charge from +5 °C to +50 °C. Below 5 °C (41 °F) the battery can still run loads, but no source, solar, alternator or shore power, is allowed to charge it. On a winter morning in a van that is the normal state of the battery, so the system has to either warm the battery first or hold charging back until it does.
The two windows
| Discharge | Charge | |
|---|---|---|
| Lithium Smart 12.8 V (100 / 200 / 330 Ah) | −20 °C to +50 °C | +5 °C to +50 °C |
| Lithium NG 12.8 V (100 / 150 / 200 / 300 Ah) | −20 °C to +50 °C | +5 °C to +50 °C |
Neither technical data page we read lists a built-in heater for these models or quantifies how much energy is lost at low temperature; we do not add a figure.
Where the battery sits decides the morning
A battery mounted under the floor or in an unheated bay follows the outside temperature. One inside the living space follows the cabin. If the van is heated overnight, an interior battery is usually inside the charge window by the time the sun or the engine could charge it; an exterior one may not be until midday, and in a cold snap not at all.
What has to stop, and what does not
- Stop: the solar controller, the DC-DC charger and the shore charger, all of which push current into the battery.
- Continue: the loads, which draw from it; the discharge window runs to −20 °C.
A charger that keeps going below the window is doing what the data sheet says not to do; how a given controller learns the battery temperature is a system-design question we have not verified for these products and leave to Victron's documentation.
Planning a winter trip around it
- Start full. The battery will carry the loads overnight on what it has; charging may not resume until it warms.
- Count on the engine for heat before you count on it for charge: a DC-DC charger delivers nothing until the battery reaches 5 °C.
- Size for the discharge, not the recharge: a 100 Ah battery is 1,280 Wh regardless of weather, and a cold morning with no charging means that is the whole budget until the window reopens.
Shopping for one? Browse RV and off-grid solar panels →
Sources
- Victron Energy — Lithium Smart Battery Manual, 7. Technical data
- Victron Energy — Lithium NG 12,8 V manual, Technical data
We have not tested these products. Specs, prices, stock and terms are as published on these pages on the date above and can change; check the manufacturer or retailer before you buy.