Go Back   EcoModder Forum > EcoModding > Fossil Fuel Free
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 03-01-2011, 06:20 AM   #11 (permalink)
Master EcoModder
 
JasonG's Avatar
 
Join Date: May 2009
Location: Charlotte NC / York SC
Posts: 726

05 DMax - '05 Chevrolet 2500HD
90 day: 18.48 mpg (US)
Thanks: 107
Thanked 54 Times in 50 Posts
Just to clarify, I'm not talking addind additional weight,motors,Tesla coils, etc.

I am asking if taking an "existing" say 400AH battery pack, and dividing it in half. (OK I added 2 large relays)

Would the rest time give the batteries more range the using them in parrallel thereby stressing them less ? ?

__________________




I can't understand why my MPG's are so low..........
21,000lb, 41' Toy Haulers are rough on FE!
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 03-01-2011, 06:34 AM   #12 (permalink)
dcb
needs more cowbell
 
dcb's Avatar
 
Join Date: Feb 2008
Location:
Posts: 5,038

pimp mobile - '81 suzuki gs 250 t
90 day: 96.29 mpg (US)

schnitzel - '01 Volkswagen Golf TDI
90 day: 53.56 mpg (US)
Thanks: 158
Thanked 267 Times in 210 Posts
Pretty sure it wont help. The batteries will be twice as stressed when they are being used, and the peukert effect isn't linear, it gets worse the more you stress a battery.



Also the battery is part of the circuit, if you have two in parallel, you effectively "halve" the internal resistance of one battery.
__________________
WINDMILLS DO NOT WORK THAT WAY!!!

Last edited by dcb; 03-01-2011 at 06:40 AM..
  Reply With Quote
Old 03-01-2011, 01:50 PM   #13 (permalink)
EcoModding Lurker
 
Join Date: Feb 2011
Location: jackson Michigan
Posts: 26
Thanks: 1
Thanked 0 Times in 0 Posts
I agree. You need exacly the right size motor and batteries to match the size of the car.
The performace will not get better by carrying batteries that are not active in the circuit.
  Reply With Quote
Old 03-01-2011, 01:51 PM   #14 (permalink)
(:
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 12,761

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,584
Thanked 3,546 Times in 2,215 Posts
Maybe you just need to P&G.
__________________


  Reply With Quote
Old 03-01-2011, 01:53 PM   #15 (permalink)
EcoModding Lurker
 
Join Date: Feb 2011
Location: jackson Michigan
Posts: 26
Thanks: 1
Thanked 0 Times in 0 Posts
Oh but, the performance gets better if you stop and replace the batteries every few miles. That way you only carry the weight required to run the motor until the next stop.
  Reply With Quote
Old 03-01-2011, 02:21 PM   #16 (permalink)
Master EcoModder
 
Phantom's Avatar
 
Join Date: Jan 2010
Location: Independence, KY
Posts: 602

Blue Meanie - '02 Volkswagon Golf TDI
TEAM VW AUDI Group
90 day: 48.52 mpg (US)

Wife's car - '05 WV Passat TDI

Rudy - '94 Chevy C2500
Thanks: 89
Thanked 46 Times in 43 Posts
I have thought about this and posted in a different thread, what would be the difference in run time if:

1: Run two banks both at 40v only having one connected till it is at 20v then run the second bank till it's at 20v. When both are at 20v run them in series for a total voltage of 40 again.

2: Run the same number of batteries in parallel/series for the same starting 40v.
__________________
I move at the speed of awesome.


"It's not rocket surgery!" -MetroMPG
  Reply With Quote
Old 03-01-2011, 02:44 PM   #17 (permalink)
EcoModding Lurker
 
Join Date: Feb 2011
Location: jackson Michigan
Posts: 26
Thanks: 1
Thanked 0 Times in 0 Posts
voltage verses current

Interesting thought. I think just regulating voltage from a series string of batteries might help keep the car runnng at a constant speed for a longer time. What if you have 120 volts to start and the motor only needs 96v. If you can use a regulator to hold the output at 96 you can discharge 24 volts before the car slows down. Changeing from series to parralled or vice versa will not change available watts but you can choose either higher current or higher voltage.
  Reply With Quote
Old 03-01-2011, 03:50 PM   #18 (permalink)
Administrator
 
Daox's Avatar
 
Join Date: Dec 2007
Location: Germantown, WI
Posts: 11,166

CM400E - '81 Honda CM400E
90 day: 51.49 mpg (US)

Daox's Grey Prius - '04 Toyota Prius
Team Toyota
90 day: 49.53 mpg (US)

Daox's Insight - '00 Honda Insight
90 day: 64.33 mpg (US)

Swarthy - '14 Mitsubishi Mirage DE
Mitsubishi
90 day: 56.69 mpg (US)
Thanks: 2,464
Thanked 2,535 Times in 1,529 Posts
Its all about amperage with batteries, especially lead acid. The faster you drain them, the less capacity they have (aka the peukert effect). Keep the amperage as low as possible and they last longer. Thats really about all there is to it. The more voltage you have, the less amperage you need. Therefore higher voltage is better for your pack.
__________________
Current project: A better alternator delete
  Reply With Quote
Old 03-01-2011, 05:33 PM   #19 (permalink)
Master EcoModder
 
Ryland's Avatar
 
Join Date: Jan 2008
Location: Western Wisconsin
Posts: 3,903

honda cb125 - '74 Honda CB 125 S1
90 day: 79.71 mpg (US)

green wedge - '81 Commuter Vehicles Inc. Commuti-Car

Blue VX - '93 Honda Civic VX
Thanks: 867
Thanked 433 Times in 353 Posts
Quote:
Originally Posted by Phantom View Post

1: Run two banks both at 40v only having one connected till it is at 20v then run the second bank till it's at 20v. When both are at 20v run them in series for a total voltage of 40 again.
What kind of battery can you drain that low tho? my 48v pack starts out at 100% full with a at rest voltage of around 52v once the at rest voltage is around 46 volts the pack is dead but in normal use I try to keep it above 47.5v to make my pack last longer as the deeper I discharge the fewer cycles I can get out of the pack.
Also the comment about a 120v battery pack and reducing the voltage to 96v going to the motor, that is more or less how speed controllers work, you give the motor the voltage it needs to go the speed you want to go, crawling along in traffic? your 120v pack might be reduced down to 20v via the speed controller.
The fact of the matter remains, stress your batteries to much and you will be replacing then every year or two instead of every 5-6 years, take really good care of them and they might last you ten years.
  Reply With Quote
Old 03-01-2011, 10:06 PM   #20 (permalink)
EcoModding Apprentice
 
Join Date: Nov 2010
Location: Annapolis
Posts: 159
Thanks: 0
Thanked 29 Times in 24 Posts
Quote:
Originally Posted by byte312 View Post
Interesting thought. I think just regulating voltage from a series string of batteries might help keep the car runnng at a constant speed for a longer time. What if you have 120 volts to start and the motor only needs 96v. If you can use a regulator to hold the output at 96 you can discharge 24 volts before the car slows down. Changeing from series to parralled or vice versa will not change available watts but you can choose either higher current or higher voltage.
That's a slightly misleading explanation.

If you need 96V from a 128V battery, the motor controller uses a 75% pulse. During the 25% 'off' period the motor current is provided by diodes or diode-like freewheel switching. Also during the off period the controller's smoothing capacitors recharge to provide part of the current for the next pulse.

As the voltage drops, the pulse width increases to compensate. Less of the current comes from the freewheel devices, and more current comes from the batteries.

A modern controller can do this very efficiently, at a frequency so high the motor current is almost constant. This is *far* more efficient than slowly switching banks of batteries in various combinations of serial, parallel and anti-series. (Anti-series is reversing/recharging one bank to effectively drop the voltage across the motor.)

  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com