Alternate Battery Hookup Question

[russtafarian]

Since I have some SLA batteries lying around, I'd like to try them with my quickie.  Here's what I'm thinking: 12v SLA > 12v SLA > 12v SLA = 36v.  For 1.5v, tap off one of the 12v SLAs and regulate down to 1.5v.

In the kit, the 1.5v D cells are not tied to ground.  Can the 1.5v share the same ground as the 36v or does it need to be isolated?  Thanks.

Russ

[Paul Birkeland]

Since I have some SLA batteries lying around, I'd like to try them with my quickie.  Here's what I'm thinking: 12v SLA > 12v SLA > 12v SLA = 36v.  For 1.5v, tap off one of the 12v SLAs and regulate down to 1.5v.

In the kit, the 1.5v D cells are not tied to ground.  Can the 1.5v share the same ground as the 36v or does it need to be isolated?  Thanks.

Russ

The 12v stack will work fine to produce the B+ instead of the 9v cells, but sharing grounds between the three supplies will result in no output from the circuit.  Also, regulating 1.5v off the bottom battery will drain it very, very quickly. 

-Paul

[Paul Joppa]

As PB says, the1.5v batteries are floating for a reason. You could do this with a conversion to fixed bias, but remember the current drain would be 200mA which might drain the SLA pretty fast.

[russtafarian]

Thanks for the input.  When I get around to trying this (thought I'd have time over Thanksgiving weekend), I'll experiment with three 12V SLAs for the 36V and a separate SLA regulated down for 1.5v.

Russ

[Paul Birkeland]

Be sure to use two separate regulators to make the 1.5v, one for each channel. 
-PB

[russtafarian]

Thanks, I'll make sure I use two regulators, one for each tube.