OT - Powering via Batteries
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Posts: 46,084
I have a robot that I am working with that needs a variety of different
voltages to power the different subsystems.
Onboard are a pair of 12v SLAs that can deliver all the current I need for
the two drive motors and the four other operational motors on the robot at
12v.
I also have a bunch of regulated power supplies that I want to drive at 24v
to produce the needed 12v, 9v, and 6v lines for the logic, servos and
communications gear.
To further complicate matters, I have several 12v, relatively high current
accessories that need to be directly coupled to the batteries individually
(rather than come through the regulators).
Here is my dilemma (and I'm sure there is an easy solution, but I am an
electronics idiot savant - I can work with the detail stuff but the basics
elude me):
How do I distribute the loads?
I need to have each of the batteries available to power different parts of
the robot directly AND I need to hook them up in series to produce the 24v
for the regulated supplies.
Obviously, if a device that is using the "top" cell of the series shares a
ground with a device that uses the whole stack, there will be trouble.
Is there something that can be done simply with diodes that will separate
the "center tap" of the battery stack but still support the current loads?
Sorry for the use of bandwidth and thanks in advance for any of your helpful
replies!
---
Jeff Abrams
jeff@m...
TURBOCHARGED & INTERCOOLED 2.5 liter 1993 Mazda MX-3 GS
TURBOCHARGED & INTERCOOLED 1.8 liter 1997 Mazda MX-5 Miata
http://www.mazdamaniac.com
As I bit into the nectarine, it had a crisp juiciness about it that was very
pleasurable - until I realized it wasn't a nectarine at all, but A HUMAN
HEAD!!
voltages to power the different subsystems.
Onboard are a pair of 12v SLAs that can deliver all the current I need for
the two drive motors and the four other operational motors on the robot at
12v.
I also have a bunch of regulated power supplies that I want to drive at 24v
to produce the needed 12v, 9v, and 6v lines for the logic, servos and
communications gear.
To further complicate matters, I have several 12v, relatively high current
accessories that need to be directly coupled to the batteries individually
(rather than come through the regulators).
Here is my dilemma (and I'm sure there is an easy solution, but I am an
electronics idiot savant - I can work with the detail stuff but the basics
elude me):
How do I distribute the loads?
I need to have each of the batteries available to power different parts of
the robot directly AND I need to hook them up in series to produce the 24v
for the regulated supplies.
Obviously, if a device that is using the "top" cell of the series shares a
ground with a device that uses the whole stack, there will be trouble.
Is there something that can be done simply with diodes that will separate
the "center tap" of the battery stack but still support the current loads?
Sorry for the use of bandwidth and thanks in advance for any of your helpful
replies!
---
Jeff Abrams
jeff@m...
TURBOCHARGED & INTERCOOLED 2.5 liter 1993 Mazda MX-3 GS
TURBOCHARGED & INTERCOOLED 1.8 liter 1997 Mazda MX-5 Miata
http://www.mazdamaniac.com
As I bit into the nectarine, it had a crisp juiciness about it that was very
pleasurable - until I realized it wasn't a nectarine at all, but A HUMAN
HEAD!!
Comments
Don't use the "centre tap" of the cells as "ground" but, the negative
terminal of the bottom cell. This will give you +12 & + 24 referenced to
the "ground" terminal. +6 +9 etc, can be regulated from the + 12 point.
If you need any negative (-) supplies (referenced to gnd), (at modest
currents) there are easy ways to generate them as well.
GND +12 +24
(-)----(+)--(-)
(+)
BATT1 LINK BATT2
Rob
Original Message
From: Jeff Abrams [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=DQWOpu7shHvrPdmBgZA88TD6sjyKRfQkwvs56GB8pDUMMedpg8O7d3j3bls4vWdba33fNyVNAZtmrBTN4d4E]clavier@b...[/url
Sent: 26 March 2003 04:22
To: Basicstamps@Yahoogroups. Com
Subject: [noparse][[/noparse]basicstamps] OT - Powering via Batteries
I have a robot that I am working with that needs a variety of different
voltages to power the different subsystems.
Onboard are a pair of 12v SLAs that can deliver all the current I need
for
the two drive motors and the four other operational motors on the robot
at
12v.
I also have a bunch of regulated power supplies that I want to drive at
24v
to produce the needed 12v, 9v, and 6v lines for the logic, servos and
communications gear.
To further complicate matters, I have several 12v, relatively high
current
accessories that need to be directly coupled to the batteries
individually
(rather than come through the regulators).
Here is my dilemma (and I'm sure there is an easy solution, but I am an
electronics idiot savant - I can work with the detail stuff but the
basics
elude me):
How do I distribute the loads?
I need to have each of the batteries available to power different parts
of
the robot directly AND I need to hook them up in series to produce the
24v
for the regulated supplies.
Obviously, if a device that is using the "top" cell of the series shares
a
ground with a device that uses the whole stack, there will be trouble.
Is there something that can be done simply with diodes that will
separate
the "center tap" of the battery stack but still support the current
loads?
Sorry for the use of bandwidth and thanks in advance for any of your
helpful
replies!
---
Jeff Abrams
jeff@m...
TURBOCHARGED & INTERCOOLED 2.5 liter 1993 Mazda MX-3 GS
TURBOCHARGED & INTERCOOLED 1.8 liter 1997 Mazda MX-5 Miata
http://www.mazdamaniac.com
As I bit into the nectarine, it had a crisp juiciness about it that was
very
pleasurable - until I realized it wasn't a nectarine at all, but A HUMAN
HEAD!!
To UNSUBSCRIBE, just send mail to:
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bottom cell.
I want to run one motor on one cell and the other motor on the other cell.
However, both motors may end up having a common ground because of the motor
controller's connection to the PCM receiver. The PCM receiver is pulling
power from a regulator that is tapped across BOTH batteries.
---
Jeff Abrams
jeff@m...
TURBOCHARGED & INTERCOOLED 2.5 liter 1993 Mazda MX-3 GS
TURBOCHARGED & INTERCOOLED 1.8 liter 1997 Mazda MX-5 Miata
http://www.mazdamaniac.com
I think one way the cops could make money would be to
hold a murder weapons sale. Many people could really use used ice picks.
Original Message
From: Rob [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=tO-ath5DIv4f8MGI0kfWrIUzBbuCcEVqxmjiai15qzhdVlOF-6rLw9QMyD17DlGPtLXefO4AQflUcI9S5CtVFNEN2A]robbed666@b...[/url
Sent: Wednesday, March 26, 2003 2:19 AM
To: basicstamps@yahoogroups.com
Subject: RE: [noparse][[/noparse]basicstamps] OT - Powering via Batteries
Hi,
Don't use the "centre tap" of the cells as "ground" but, the negative
terminal of the bottom cell. This will give you +12 & + 24 referenced to
the "ground" terminal. +6 +9 etc, can be regulated from the + 12 point.
If you need any negative (-) supplies (referenced to gnd), (at modest
currents) there are easy ways to generate them as well.
GND +12 +24
(-)----(+)--(-)
(+)
BATT1 LINK BATT2
Rob
Original Message
From: Jeff Abrams [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=DjaO_10kitDQPaEfP9l199Cn4cm635zHRKxxRukFkYgt8roqupGajxV0yQVMAhRssOzDg4X7VYLjfNAEveFI]clavier@b...[/url
Sent: 26 March 2003 04:22
To: Basicstamps@Yahoogroups. Com
Subject: [noparse][[/noparse]basicstamps] OT - Powering via Batteries
I have a robot that I am working with that needs a variety of different
voltages to power the different subsystems.
Onboard are a pair of 12v SLAs that can deliver all the current I need
for
the two drive motors and the four other operational motors on the robot
at
12v.
I also have a bunch of regulated power supplies that I want to drive at
24v
to produce the needed 12v, 9v, and 6v lines for the logic, servos and
communications gear.
To further complicate matters, I have several 12v, relatively high
current
accessories that need to be directly coupled to the batteries
individually
(rather than come through the regulators).
Here is my dilemma (and I'm sure there is an easy solution, but I am an
electronics idiot savant - I can work with the detail stuff but the
basics
elude me):
How do I distribute the loads?
I need to have each of the batteries available to power different parts
of
the robot directly AND I need to hook them up in series to produce the
24v
for the regulated supplies.
Obviously, if a device that is using the "top" cell of the series shares
a
ground with a device that uses the whole stack, there will be trouble.
Is there something that can be done simply with diodes that will
separate
the "center tap" of the battery stack but still support the current
loads?
Sorry for the use of bandwidth and thanks in advance for any of your
helpful
replies!
---
Jeff Abrams
Can you give us some idea of what current level you require from each
supply volt you need? A receiver should only be a few 100mA's MAX,
miniature DC-DC converters are cheap (up to a few Watts), and some only
the size of a DIL package. Using isolated DC-DC converters, you can
reference multiple voltage sources, both positive and negative to a
common ground. Am I right in assuming you main current draw will be by
the 12 motors, and the 24 volt current requirement is small? Just list
the voltages and what you intend to connect to them. A DC-DC converter
does appear to be your receiver (24 volt?) answer. In fact using
isolated DC-DC converters the batteries can be left to "float" and the
ground used for logic and control only. Are you using "H" bridges to
drive the motors ?.
Rob
Original Message
From: Jeff Abrams [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=gJfk7QeuVX_TM9KCmQTClgqUjlG1kuyXhIhqtCHV00rbNSLGj0MbXHu8VYcP5SeAAVQils2M3rpO60kyNv6DmHom2Q]clavier@b...[/url
Sent: 26 March 2003 07:28
To: basicstamps@yahoogroups.com
Subject: RE: [noparse][[/noparse]basicstamps] OT - Powering via Batteries
But this would mean that all of my 12v sources would be pulling from the
bottom cell.
I want to run one motor on one cell and the other motor on the other
cell.
However, both motors may end up having a common ground because of the
motor
controller's connection to the PCM receiver. The PCM receiver is pulling
power from a regulator that is tapped across BOTH batteries.
---
Jeff Abrams
jeff@m...
TURBOCHARGED & INTERCOOLED 2.5 liter 1993 Mazda MX-3 GS
TURBOCHARGED & INTERCOOLED 1.8 liter 1997 Mazda MX-5 Miata
http://www.mazdamaniac.com
I think one way the cops could make money would be to
hold a murder weapons sale. Many people could really use used ice picks.
Original Message
From: Rob [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=nKe8BS46WNBm-12TdAtzpJXWc1_z6TBU4ie8id4FlgmNTyAjoF3AfAJ_cBgK9DvyAuzT0MCZj0s8a1bOxT-kpGCz]robbed666@b...[/url
Sent: Wednesday, March 26, 2003 2:19 AM
To: basicstamps@yahoogroups.com
Subject: RE: [noparse][[/noparse]basicstamps] OT - Powering via Batteries
Hi,
Don't use the "centre tap" of the cells as "ground" but, the negative
terminal of the bottom cell. This will give you +12 & + 24 referenced to
the "ground" terminal. +6 +9 etc, can be regulated from the + 12 point.
If you need any negative (-) supplies (referenced to gnd), (at modest
currents) there are easy ways to generate them as well.
GND +12 +24
(-)----(+)--(-)
(+)
BATT1 LINK BATT2
Rob
Original Message
From: Jeff Abrams [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=gJfk7QeuVX_TM9KCmQTClgqUjlG1kuyXhIhqtCHV00rbNSLGj0MbXHu8VYcP5SeAAVQils2M3rpO60kyNv6DmHom2Q]clavier@b...[/url
Sent: 26 March 2003 04:22
To: Basicstamps@Yahoogroups. Com
Subject: [noparse][[/noparse]basicstamps] OT - Powering via Batteries
I have a robot that I am working with that needs a variety of different
voltages to power the different subsystems.
Onboard are a pair of 12v SLAs that can deliver all the current I need
for
the two drive motors and the four other operational motors on the robot
at
12v.
I also have a bunch of regulated power supplies that I want to drive at
24v
to produce the needed 12v, 9v, and 6v lines for the logic, servos and
communications gear.
To further complicate matters, I have several 12v, relatively high
current
accessories that need to be directly coupled to the batteries
individually
(rather than come through the regulators).
Here is my dilemma (and I'm sure there is an easy solution, but I am an
electronics idiot savant - I can work with the detail stuff but the
basics
elude me):
How do I distribute the loads?
I need to have each of the batteries available to power different parts
of
the robot directly AND I need to hook them up in series to produce the
24v
for the regulated supplies.
Obviously, if a device that is using the "top" cell of the series shares
a
ground with a device that uses the whole stack, there will be trouble.
Is there something that can be done simply with diodes that will
separate
the "center tap" of the battery stack but still support the current
loads?
Sorry for the use of bandwidth and thanks in advance for any of your
helpful
replies!
---
Jeff Abrams
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject
and Body of the message will be ignored.
Your use of Yahoo! Groups is subject to
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motors. They max out at 30A, but typically I won't be pulling more than
15A - 20A. I have two more motors driving the arms that are wired the same
way and one more that turns the head. Up and down on the head is via servo.
I need to pull about 6A of regulated 12v, 3A of regulated 9v and less than
1A of regulated 6V.
I also need to draw power directly from the two batteries individually to
power some high current items like a TV/VGA monitor, a Dell laptop and a
power amplifier as well as a 1W video amp and transmitter.
The problem is that some of the items powered by the "raw" batteries will be
in common contact with the regulated items, effectively shorting the bottom
cell.
For those of you that are interested in the thing as a whole, you can look
here:
http://www.washingtontalent.com/sprockit/index.shtml
I build those things. Don't laugh.
I was running the batteries in parallel, but I found that the 12V
electronics were too sensitive to voltage drop and discharge. This gave
diminished performance as the batteries reached the end of their charge.
I want to run the batteries in series to get every last drop out of them
before the robot goes blind/deaf/mute.
---
Jeff Abrams
jeff@m...
TURBOCHARGED & INTERCOOLED 2.5 liter 1993 Mazda MX-3 GS
TURBOCHARGED & INTERCOOLED 1.8 liter 1997 Mazda MX-5 Miata
http://www.mazdamaniac.com
If they ever come up with a swashbuckling School, I think one of the
courses should be Laughing, Then Jumping Off Something.
Original Message
From: Rob [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=dYFUFS15PzsYBdsDO3BFkhXbxkOQH3fr5T345iX7ZNAjfFkfkP1YVTBt6WpUP0jBPdOjuWYZvc6kO7syXOE]robbed666@b...[/url
Sent: Wednesday, March 26, 2003 1:17 PM
To: basicstamps@yahoogroups.com
Subject: RE: [noparse][[/noparse]basicstamps] OT - Powering via Batteries
Ok Jeff,
Can you give us some idea of what current level you require from each
supply volt you need? A receiver should only be a few 100mA's MAX,
miniature DC-DC converters are cheap (up to a few Watts), and some only
the size of a DIL package. Using isolated DC-DC converters, you can
reference multiple voltage sources, both positive and negative to a
common ground. Am I right in assuming you main current draw will be by
the 12 motors, and the 24 volt current requirement is small? Just list
the voltages and what you intend to connect to them. A DC-DC converter
does appear to be your receiver (24 volt?) answer. In fact using
isolated DC-DC converters the batteries can be left to "float" and the
ground used for logic and control only. Are you using "H" bridges to
drive the motors ?.
Rob
Original Message
From: Jeff Abrams [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=z3_BusdnlufSHz6whYlemaGIqa1UDlWBWnXpETsUwPaqromA_50JAspDyrL5QXwEJ0xLVa8ywQXruOyP6vUqeA]clavier@b...[/url
Sent: 26 March 2003 04:22
To: Basicstamps@Yahoogroups. Com
Subject: [noparse][[/noparse]basicstamps] OT - Powering via Batteries
I have a robot that I am working with that needs a variety of different
voltages to power the different subsystems.
Onboard are a pair of 12v SLAs that can deliver all the current I need
for
the two drive motors and the four other operational motors on the robot
at
12v.
I also have a bunch of regulated power supplies that I want to drive at
24v
to produce the needed 12v, 9v, and 6v lines for the logic, servos and
communications gear.
To further complicate matters, I have several 12v, relatively high
current
accessories that need to be directly coupled to the batteries
individually
(rather than come through the regulators).
Here is my dilemma (and I'm sure there is an easy solution, but I am an
electronics idiot savant - I can work with the detail stuff but the
basics
elude me):
How do I distribute the loads?
I need to have each of the batteries available to power different parts
of
the robot directly AND I need to hook them up in series to produce the
24v
for the regulated supplies.
Obviously, if a device that is using the "top" cell of the series shares
a
ground with a device that uses the whole stack, there will be trouble.
Is there something that can be done simply with diodes that will
separate
the "center tap" of the battery stack but still support the current
loads?
Sorry for the use of bandwidth and thanks in advance for any of your
helpful
replies!
---
Jeff Abrams