‍Occasionally, we get questions about using StimTracker with batteries. We purchased a TalentCell 12V 6000mAh lithium ion rechargeable battery pack and tested it with StimTracker. Its DC plug matches the diameter of the DC jack in StimTracker. It works well with all StimTracker models and we recommend it. Depending on use, a battery charge will last from a full day at worst to a few days.

‍Why Use a Battery?

‍In an ideal world, one would not be necessary. But there are sources of noise in the environment that can seep into the EEG data, e.g. nearby machinery or electric motors. Sometimes, it is the quality itself of the power that’s being delivered to your building. Taking the feedback from the original StimTracker (model ST-100) into account, the design of StimTracker Duo and Quad includes steps to not only reduce its own contribution to the electrical environment, but also to be more tolerant of the environment itself. 

‍The first step was to replace the included AC adapter with another model that has a grounded input; it uses a three prong AC cord instead of a two prong cord.

‍Speaking of which, please refrain from using “cheater plugs” like the one in the picture as this not only negates the noise suppression of the power supply, but can also make it worse by turning the ungrounded earth lead into an antenna.

‍The original StimTracker used a double-sided printed circuit board (PCB). When designing the second generation Duo and Quad models, we moved to a four-layer circuit board with integral planes. The sole purpose of those inner planes is improving noise immunity.

‍Because the role of StimTracker is to connect directly to multiple devices having different power sources and designs, it can be very difficult to implement a generic noise management scheme that suits all cases. A fast and effective solution for many situations is to power StimTracker from a battery.

‍How Long Would it Last?

‍This depends on how you are using StimTracker, of course. It’s best to illustrate with an example.

‍The recommended battery has a 6000mAh capacity. A StimTracker Quad with two m-pods connected (an Analog m-pod and another TTL-based m-pod) would draw about 150mA. Let’s rounded it up to 200mA as a safety margin. The battery would last at least 30 hours (that’s 6000mAh divided by 200), and longer if using a single m-pod.

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