Hi Mike,
Just to clarify a little, the dAck! uses exactly what you're talking about - sealed lead acid - sorry if I was not clear in my previous post. Part of the design intent was to make something small, reasonably lightweight, inexpensive, and somewhat portable. I designed the thing with vinylphiles in mind with the knowledge that they're quite used to interactivity with their systems. Hence the small batteries - they are the largest that will fit inside the enclosure.
I could have easily spec'ed out large batteries, but like you probably know, engineering design is about compromise. It would quadruple the weight, move batteries outside the enclosure, and considerably increase the cost of the unit: extra enclosure requirements, need for durable and attractive wiring, and don't forget - overcurrent protection. This would give you a charging cyle of 24 hours to a couple days, depending on the size of the batteries.
This isn't an amp circuit or anything (it draws 100mA on average), so you're not going to get some night and day improvement by going to 42Ah. It's a bigger jump going from regulated AC-DC PSU to power cells. But yes, it does sound better (minorly) with larger cells.
Don't worry - I have some alternatives up my sleeve for you guys who just don't dig the battery thing. The system is designed modularly and new developments can be added to the existing system quite easily. What does this mean? Well you can probably figure it out from the above discussion :).
Thanks for the feedback.
-Chris
Just to clarify a little, the dAck! uses exactly what you're talking about - sealed lead acid - sorry if I was not clear in my previous post. Part of the design intent was to make something small, reasonably lightweight, inexpensive, and somewhat portable. I designed the thing with vinylphiles in mind with the knowledge that they're quite used to interactivity with their systems. Hence the small batteries - they are the largest that will fit inside the enclosure.
I could have easily spec'ed out large batteries, but like you probably know, engineering design is about compromise. It would quadruple the weight, move batteries outside the enclosure, and considerably increase the cost of the unit: extra enclosure requirements, need for durable and attractive wiring, and don't forget - overcurrent protection. This would give you a charging cyle of 24 hours to a couple days, depending on the size of the batteries.
This isn't an amp circuit or anything (it draws 100mA on average), so you're not going to get some night and day improvement by going to 42Ah. It's a bigger jump going from regulated AC-DC PSU to power cells. But yes, it does sound better (minorly) with larger cells.
Don't worry - I have some alternatives up my sleeve for you guys who just don't dig the battery thing. The system is designed modularly and new developments can be added to the existing system quite easily. What does this mean? Well you can probably figure it out from the above discussion :).
Thanks for the feedback.
-Chris