Fishman pickups and expected battery life
All active or powered pickups need power to operate. How long the battery will last is a question that can't be answered without knowledge about two things. These two things are the current draw of the pickups and the capacity of the battery.
Ok, so what's current draw?
This refers to current consumed by a device when plugged in and is commonly expressed in mA or uA (1mA = 1000uA). For example, the current draw of a Fishman Fluence modern humbucker is 2,5mA (2500uA). This refers to one pickup only and to get the whole picture, one must add the draw of all active components to calculate the total current draw of the instrument. A dual Fishman Fluence humbucker-equipped guitar is therefore 2 X 2,5mA = 5mA total. This roughly translates into the power consumption of a common analog overdrive pedal.
Ok, what does this mean in terms of battery life?
To answer this question we have to know the capacity of the battery. There are many different kinds of batteries, all with their own capacity specifications. The most common kind of battery in terms of guitars are 9v block batteries. However, there are vast amounts of different 9v block batteries as well, just to make things complicated. Their capacity is commonly expressed in mAh (milliamp-hours) which refers to how many hours they're capable of delivering 1mA. By now, an idea about how to calculate battery life is probably starting to take shape, but let's do a couple of calculations using one of our Boden Metal guitars as the basis for comparison.
.strandberg* Boden Metal electronics
- Pickups: 2 X Fishman Fluence modern humbucker
- Total current draw (2 X 2,5mA) = 5mA
Different 9v block batteries capacities
- Standard Alkaline 9v 6LR61: Approximately 400-650mAh
- Rechargeable Alkaline 9v 6LR61: Approximately 150-250mAh
- Lithium 9v 6LR61: Approximately 700-1200mAh
- Rechargable Lithium 9v 6LR61: Approximately 500-800mAh
Estimated battery life with different battery options for a dual humbucker Fishman-equipped .strandberg* guitar
- Standard Alkaline 9v 6LR61 (400-650mAh) = 80-130 hours
- Rechargeable Alkaline 9v 6LR61 (150-250mAh) = 30-50 hours
- Lithium 9v 6LR61 (700-1200mAh) = 140-240 hours
- Rechargable Lithium 9v 6LR61 (500-800mAh) = 100-160 hours
There are a lot of different brands and types of batteries out there and these calculations are based on typical examples. Sometimes this information isn't even printed on the packaging, but you'll get a general idea. One thing's for sure and that is that you should never expect a certain amount of playing hours from any randomly chosen battery. Plugged in for 2h/day, the battery will last anywhere between 2 and 18 weeks depending on the battery chosen in the case of a Boden Metal guitar.