Cold-Charge Adapter
Charge your battery safely all winter.
What it does
A car battery can freeze in cold weather. Charging a frozen battery can ruin it. And a battery that is low on charge freezes much sooner than a full one.
This adapter goes between your charger and your battery. It reads the battery temperature and stops the charger when charging would do harm. When the battery warms up, it connects again on its own. You can leave it alone all winter.
What the lights mean
| Green, steady | The charger is connected to the battery. All is well. |
| Red, one blink every 10 seconds | Awake and waiting. There is no charger, or nothing is hooked up yet. |
| Red, one flash every 2 seconds | The battery is too cold to charge. This is normal. Leave it be — it will connect when the battery warms up. |
| Red, two flashes, then a pause | The sensor is broken, loose or unplugged. Check the sensor on the battery post. It will not charge until this is fixed. |
| No light at all | No power. Check that the battery is hooked up the right way round. |
Before you use it
12 volt lead-acid batteries only. Do not use it with lithium batteries. They freeze and fail in a different way, and this adapter would give you the wrong answer.
The sensor must be bolted to the battery post. If it is loose, or clipped to something else, the adapter is reading the wrong thing. It will refuse to charge rather than guess.
This board
Board REV 20260728, built from tag
hw-rev-20260728. Quote both if you ask about a board.