The microprocessor remembers your last settings. If you always charge 12V AGM batteries, the charger will default to that mode upon power-up, saving you time.

While TGC uses different codes across revisions, the most common BC-90-1H error codes are:

If your charger is beeping or the display is flashing, the tgc bc-90-1h manual’s troubleshooting chapter is your best friend. Here are the most common codes:

| Error Code | Meaning | Solution from Manual | | :--- | :--- | :--- | | E01 | Reverse polarity | The clamps are on the wrong terminals. Swap red and black immediately. | | E02 | Short circuit / Bad cell | Battery likely has an internal short. Test with a multimeter; replace battery if necessary. | | E03 | Voltage too high (over 15V for 12V) | You selected the wrong voltage (e.g., 24V for a 12V battery). Turn off and reset. | | E04 | Voltage too low (under 2V) | Battery is sulfated or deeply dead. Try “Wake Up” mode (press and hold Start for 5 seconds). | | E08 | Over-temperature | Internal unit is too hot. Move to cooler location and let the fan run for 30 minutes. |