The Touch Board can be used with a single Lithium Ion or Lithium Polymer cell (3.7V). These are often referred to as LiPo batteries for short. Other batteries are not ideal as you will not be able to re-charge them with the on-board LiPo charge circuit.
If you connect the LiPo battery to the Touch Board and turn it on and the green light of the Touch Board doesn't illuminate, your LiPo battery may need recharging. The Touch Board has an onboard LiPo charging circuit that charges the battery while it’s powered via a USB cable at a safe rate of 200mA, which also extends the battery’s life. The “CHG” LED will light up when the battery is being charged. It will also automatically stop charging once the battery is full. This is indicated by the orange “CHG” LED turning off.
You can get hold of a Touch Board compatible battery from many suppliers. Here are a few points to double-check before purchasing:
- Is it a Lithium Polymer battery (also known as a LiPo for short)? Only these batteries are rechargeable with the Touch Board.
- Does it have its own onboard protection circuitry? This is very important for use with the Touch Board. You can normally tell these apart from unprotected types by the yellow taped section at the wire end of the battery, but be sure to ask your supplier to confirm this for you.
- Is it a single cell LiPo? – Be careful of multi cell LiPo batteries often sold from Radio Control shops. Only single cells are compatible – you can usually tell as their voltage is quoted as 3.7V, not higher.
- Does it have a 2 way JST PH connector (pin 1 positive, pin 2 negative)? – It is fairly recognisable, but check with the supplier to be sure.
- Does it have a capacity rating of at least 400mAh? – A nice size is around 800mA-1200mAh for most use cases.
You can also use power banks with the Touch Board.