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rearrange batteries with relays?

B

BobG

Jan 1, 1970
0
Surely there must be a name for this subject.... an array of contactors
in a row and column arrangement of 12 batteries to allow series and
parallel connection as 12,24,36,48,72,96,and 144 volts etc? You cant
always use the bottom battery in the stack to run on slow... the
submariners must have worked all this out in the 40s....
 
D

Dan Hollands

Jan 1, 1970
0
BobG said:
Surely there must be a name for this subject.... an array of contactors
in a row and column arrangement of 12 batteries to allow series and
parallel connection as 12,24,36,48,72,96,and 144 volts etc? You cant
always use the bottom battery in the stack to run on slow... the
submariners must have worked all this out in the 40s....



What's the question?

--
Dan Hollands
1120 S Creek Dr
Webster NY 14580
585-872-2606
[email protected]
www.QuickScoreRace.com
 
B

BobG

Jan 1, 1970
0
If its been done before and is a mature technique, I just need some
keyword to look for it. If its a clever new idea of keeping batteries
leveled by parallelling at lower voltages, I'd like to brainstorm on
how to do it with mosfets or something more efficient than contactors.
Do they make latching contactors that go to zero watts after latching?
 
D

Dan Hollands

Jan 1, 1970
0
..QuickScoreRace.com
BobG said:
If its been done before and is a mature technique, I just need some
keyword to look for it. If its a clever new idea of keeping batteries
leveled by parallelling at lower voltages, I'd like to brainstorm on
how to do it with mosfets or something more efficient than contactors.
Do they make latching contactors that go to zero watts after latching?


I've never seen an application for this type of device

--
Dan Hollands
1120 S Creek Dr
Webster NY 14580
585-872-2606
[email protected]
www
 
P

Pooh Bear

Jan 1, 1970
0
BobG said:
Surely there must be a name for this subject.... an array of contactors
in a row and column arrangement of 12 batteries to allow series and
parallel connection as 12,24,36,48,72,96,and 144 volts etc? You cant
always use the bottom battery in the stack to run on slow... the
submariners must have worked all this out in the 40s....

It looks like speed was controlled by the configuration of the motor
windings

" The motor bus can be split for operation of the motors on each side
independently of the other sides (BUS TIE OPEN), closed for parallel
operation of both motor groups (BUS TIE CLOSED), connected to the battery
bus for battery operating of the main motors (BATTERY BUS), and lastly, for
series operation of all motors the positive side of one motor bus can be
cross-connected to the negative side of the other motor bus, so that by
proper closing of the motor contactors, all four motors can be placed in
series for slow-speed operation on the battery bus (SLOW).

Either or both batteries are connected to the battery bus by closing their
respective contactors which, in turn, are controlled by one operating
lever. "

http://www.maritime.org/fleetsub/chap6.htm

Graham
 
C

cbm5

Jan 1, 1970
0
BobG said:
Surely there must be a name for this subject.... an array of contactors
in a row and column arrangement of 12 batteries to allow series and
parallel connection as 12,24,36,48,72,96,and 144 volts etc? You cant
always use the bottom battery in the stack to run on slow... the
submariners must have worked all this out in the 40s....

They used four motors or a couple split-armature motors, and varied the
speed (actually, torque) by connecting the armature windings in
different combinations of series and parallel, and also by varying the
shunt fields for fine control. There are quite a few combinations
available, especially when a submerged submarine barely needs more than
"fast" and "slow".

These days most electric motors will use pulse-width modulation or
variable-frequency multiphase drives. Certainly much less complicated
than switching banks of batteries around, and you can use feedback to
make adjustments for dropping battery voltage.
 
B

BobG

Jan 1, 1970
0
OK, thanks for the info on how they did it in submarines. Back to the
present. 12 batteries seems like a nice number because it has lots of
divisors. You can get 12V with all 12 in parallel, 24V with 6 banks of
2 in series, 36V with 4 banks of 3 in series, 48V with 3 banks of 4 in
series, 72V with 2 banks of 6 in series, and 144V with all 12 in
series. Is 6 speeds enough for an electric car? (probably not), but I
get the idea that when using regen, the computer thinks... hmmm slowing
down from 30mph... motor putting out 26V.... reconfigure battery bank
to 24V... slap motor on battery bank. Or however programmers make
computers reason these things out.
 
K

kell

Jan 1, 1970
0
BobG said:
OK, thanks for the info on how they did it in submarines. Back to the
present. 12 batteries seems like a nice number because it has lots of
divisors. You can get 12V with all 12 in parallel, 24V with 6 banks of
2 in series, 36V with 4 banks of 3 in series, 48V with 3 banks of 4 in
series, 72V with 2 banks of 6 in series, and 144V with all 12 in
series. Is 6 speeds enough for an electric car? (probably not), but I
get the idea that when using regen, the computer thinks... hmmm slowing
down from 30mph... motor putting out 26V.... reconfigure battery bank
to 24V... slap motor on battery bank. Or however programmers make
computers reason these things out.

The question of how many switches you need and how many poles and
throws per switch would be a math problem. You could offer it up to a
high school teacher or a professor at a local college as something for
his students to work on, although an engineering professor might tell
you it isn't practical to use batteries that way.
 
J

Jasen Betts

Jan 1, 1970
0
OK, thanks for the info on how they did it in submarines. Back to the
present. 12 batteries seems like a nice number because it has lots of
divisors. You can get 12V with all 12 in parallel, 24V with 6 banks of
2 in series, 36V with 4 banks of 3 in series, 48V with 3 banks of 4 in
series, 72V with 2 banks of 6 in series, and 144V with all 12 in
series. Is 6 speeds enough for an electric car? (probably not), but I
get the idea that when using regen, the computer thinks... hmmm slowing
down from 30mph... motor putting out 26V.... reconfigure battery bank
to 24V... slap motor on battery bank. Or however programmers make
computers reason these things out.

AIUI they use a buck/boost voltage converter these days.
 
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