[ausev] Technical Considerations; Battery Pack Replac...

Fri Aug 11 17:53:45 GMT 2006

On heat on batteries, we have an '04 Honda Civic Hybrid and the maintenance  
manual shows, and I've looked at,  a blower fan that circulates air around  
the battery pack under the rear seat, I think sucking it in from a vent on the  
back window shelf. It is on a thermal control and runs when needed as are the 
2  front engine fans. 

There are 2 torsion bars on the car also, and it is very well controlled in  
all situations so far. 

I could get some specs on fan size etc. if that would help. I'd assume that  
the parts could be purchased from Honda. 
Chuck Simms, (contact info below.) 

In a message dated 8/10/2006 4:47:52 P.M. Central Standard Time,  jtp at onr.com 
writes:

Engine compartments can reach over 250 degrees at  times.  Many batteries 
have insulator blankets or plastic covers.   These extend the functional life 
approximately 30 percent. 
The only heat factor which is relevant, then, is  your rate of charge in an 
EV.  The more heat (faster charge rate) the  greater the reduction of endlife.  
Installing heat sensors or other  devices which can monitor heat values 
during charging may help greatly to  study appropriate charge rates for all of the 
various use, discharge, and  battery state conditions.  
 This might be more feasible as part  of bench-test studies.
Carefully recording readings with an infrared  thermometer taken of all cells 
(bottom to top) during various recharge rate  tests might be easier and 
cheaper given all that has to be  done to replace the pack.   I would contact the 
battery  manufacturer to ask about nominal rates and temperatures.
Also,  what just occurred to me, if heat-up  rates are closely comparable to 
OEM (orig. equip. manuf.), then you may  not need to be concerned about extra 
cooling of some sort. Otherwise, it  may be a good idea to get recommendations 
from the battery manufacturer about  possibly needing some additional   
active or passive cooling.  
Dan Petit.  

----- Original Message ----- 
From:  _michael_ (mailto:mringer at austin.rr.com)  
To: _'AustinEV News Announcements and General  Discussion'_ 
(mailto:ausev at austinev.org)  
Sent: Thursday, August 10, 2006 8:10  AM
Subject: *****SPAM***** Re: [ausev]  Technical Considerations;Battery Pack 
Replacement 98 Ranger

Based on all of  this, it brought me to a new question….  

In cars with  engines, heat is the major killer of batteries, I don’t know 
how many  “swelled” batteries I replaced during my grease monkey/tire jockey  
days.  Is this a concern for  Electric cars or is the heat not as much of an 
issue since it only is sun  heat and not engine and sun heat?   

(I hope that last  sentence made sense) 
Thanks! 

Michael  Ringer 
Administrative  Manager 
GCE,  Inc 
512-528-0908 
512-528-9293  FAX 
Your  Passport to education and employment 
Member  of NACES 
_http://www.naces.org_ (http://www.naces.org/) 
-----Original  Message-----
From:  ausev-bounces at austinev.org [mailto:ausev-bounces at austinev.org] On 
Behalf Of jtp
Sent: Thursday, August 10, 2006 11:46  AM
To: AustinEV News  Announcements and General Discussion
Subject: [ausev] Technical  Considerations; Battery Pack Replacement 98 
Ranger 

Additional technical aspects  worth considering in the battery pack 
replacement may relate to some of the  new advanced electrical controls on '99 and 
later  IC's.

'99 and later DC  alternators on GM vehicles, for example, use a computerized 
all-silicon  voltage regulator, which requires a specific sequence in 
reconnecting the  harness, high amp output, and ground, in order to properly "bias" 
the  charging system for it to work.    

Consideration might  be given to the possibility that components of the '98 
Electric Drive Ranger  may not only have a reconnection sequence as well, but 
possibly, the  question ought to be answered as to the potential need for a 
disconnection  sequence also.  

When inspecting the  Ranger at the "Who Killed the Electric Car" event,  I 
noticed that the  drive motor was manufactured by Siemens.  It might be a good 
idea to  see if Siemens Engineering could provide guidelines about  this  or 
anything else in the wiring  and controlling.

Since there is  apparently  a very substantial undertaking in the replacement 
of the  batteries,  I recommend that a very high level of working precision 
be  required here.  For example,  an "Inch-ounce" torque wrench in  order to 
record the removal torque required for all bolts and clamps at the  batteries, 
and making a carful decision as to minimal and maximal torque  specification at 
battery connections.  Torque should be rechecked at  least three times at 
differing temperatures (as if you were working on the  Space Shuttle).

Recording torque readings at  removal for the main tray bolts also would be 
important with a  foot-pounds torque wrench.

Since the "Sprung-weight"  of the batteries would be off of the suspension, 
and, an anticipated spring  travel will reposition front steering and 
suspension geometries, then, it  may be a good idea to lubricate any available grease 
fittings in the  "extended-travel" positions of the lubricated joints.  This in 
 anticipation of dried-out or thickened lubricants at all of the suspension  
points. 

I am very opposed to the  use of any kind of grease coating at any battery 
connection, since grease is  an insulator and can melt down between critical 
contact areas.  While  for  IC automotive (easy to access) battery sitiations I 
use clear  acrylic spray paint which keeps corrosion at bay for at least 5 
years (and  is also of some value in reducing the chance of accidental shorts as 
it has  slight, low voltage insulating value),  I can not say I could recommend 
 that for higher voltage packs at all, but only for the auxiliary voltages at 
 a 12 volt auxiliary battery only. 

Another  consideration which comes to mind, given the difficulty in this 
endeavor, is  to test cycle ALL the batteries at least a minimal number of times 
in a  similar application.  This may sound like a lot of work, but actually  
using the batteries in a similar load-scenario may be wise, such as  installing 
them (if they will fit), into an EV where the batteries could be  performance 
tested.  Then, if there is one or more which seem unable to  perform as well 
as the rest, then there ought to be an exchange requested  for the 
underperformers. 

Optional  items.  Diamler-Chysler utilizes a datastream called "Battery  
Temperature".  There is a sensor placed in the tray underneath the  battery which 
provides battery temperature as a function of  "reference  voltage" whereby 
temperature of the battery influences its internal  resistance.

(Allowing for a very nicely  accurate decision as to which mixture ratio 
schedule to  process).   This may be a really nice way to remotely monitor  
battery temperatures, but maybe on an analog basis.   Also,   performing bench 
testing of cell temps during recharging each battery after  a calibrated discharge 
(of several discharge rates) may be helpful in  preventing inadvertent 
installation of a weak battery.  

Dan Petit.  

Chuck Simms

Director, North Austin M.U.District  #1
e-mail: charlesvsi at aol.com
Phone: 512-331-9630
Cell:  505-331-1237
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