[DeTomaso] battery recommendation

Christopher Kimball chrisvkimball at msn.com
Wed Aug 19 01:53:27 EDT 2009


Your last sentence is exactly how I feel, too.  However, after cleaning the terminals on my existing battery, spraying anti-corrosion stuff on the posts and clamps and putting it all back in the car, I noticed the ammeter doesn't drop below 0 as much as it used to.  In fact, while running around this evening, with headlights on bright, all three fans running and the stereo blasting, at cruising speeds the ammeter registered just over 0, indicating a slight charge going to the battery, which I think is normal.

At idle (and the car is idling very slowly right now--in fact, at stop lights the throbbing engine shakes the car) the ammeter dipped below 0 whenever a loud bass note hit, but other than that, stayed at 0.

I may go ahead and get that new battery, though, since I don't want to get stranded when the battery dies in the middle of nowhere!

Thanks,

Chris





Date: Mon, 17 Aug 2009 23:42:57 -0700
From: rlbpantera at earthlink.net
To: chrisvkimball at msn.com
CC: detomaso at realbig.com
Subject: Re: [DeTomaso] battery recommendation






  


Chris,



Well, hard to say but maybe a few tests might help. One easy test you
could do is to jumper (with good stout jumper cables that are well
connected at both ends) your battery from another (running?) car. Warm
up the Pantera, stop it and then start it again. Note how easily (or
not) it starts. Now disconnect the jumpers and restart it again. Any
change in the speed it spins and starts? If not, the P-1 probably won't
make any difference for now (or PM-1, I think they are actually the
same, just with different guarantees with the PM-1 not as good at only
3 years). Remember with a conventional battery you're only one or two
deep discharges from a toasted battery.



If both starts seem to be less strong than they should be you might try
checking the voltage drops in your system. I have no idea what they
should be but I would think something less than 0.5 V might be
reasonable from the stand point cranking power lost. At 0.5 V there
would be about an 8% loss in cranking power. This is roughly linear at
this point so 1 V about 16% and 0.25 V about a 4% loss.



A few weeks ago I helped Grant Stockwell troubleshoot why his car would
barely start. Part of it was that his battery was on its last legs.
However we also discovered some seemingly large voltage drops while it
was cranking. The first suspect was the disconnect gizmo he has between
his + terminal and the battery cable. The drop was about 1.3 V while
cranking. After cleaning it up and applying OX-GARD (discussed in may
http://list.realbig.com/pipermail/detomaso/2009-May/109522.html), the
voltage drop was close to 0 V. Then we tested the drop between the +
terminal and the starter motor. It was almost 2 V!! He was loosing
about 30% of his cranking power. His setup has the original battery
cable going to the solenoid on the firewall and then a new cable
attached to the old one going to the solenoid on his gear reduction
starter motor. The voltage drop to the junction at the original
solenoid was about 1.2 V meaning there was about a .8 V drop on the
short cable to the starter. Obviously some bad connections somewhere.
It was getting late and didn't have time to figure it out. I just
talked to Grant and the new P-1 starts the engine (hot) just fine. It
would be even better without the 2 V drop.



Question for the List: What is a typical voltage drop across the stock
Pantera battery cable during starting? I realize this is completely
dependent on the starting current (and of course the resistance). If
the starting current is 200 amps (a number I've heard mentioned for
cars) then the 2 V drop would mean a resistance of 0.01 Ohms. Not much
and not something I can't measure directly. Alternatively, what is the
gauge of the stock battery cable? According to this chart
(http://www.stealth316.com/2-wire-resistance.htm) 10' of 4 gauge wire
should have a resistance of only 0.0025 ohms. which would give a 0.5 V
drop at 200 amps. Also, I just found this reference
http://tinyurl.com/m5uetv that states that if the starting voltage from
the starter to ground is greater than 9.6 V then the system is probably
working as it should. By the way, the internal resistance of the
P-1/PM-1 is about 0.004 Ohms which would give a drop of 0.8 V at 200
amps.



To answer your question directly though, I'd get the PM-1 (or P-1) now.
With batteries and tires I always try to replace them before they fail.
Squeezing out a little extra just isn't worth it to me.



Richard



Christopher Kimball wrote:

  Dear Richard,

 

I went to Sears today all set to spend $240 on a new Platinum PM-1.  I
took in the existing battery from my Pantera, which was a
2003, 72-month battery.  I figured if it were a bit lame it might not
have enough "oomph" to get the starter turning a few more rpms when
it's hot.  

 

They checked the existing battery and they said it was in great shape.

 

Since my battery is about at the end of it's natural life, and since my
starter is relatively new (and I don't feel like spending more money on
a starter), should I get the PM-1 anyway, or wait?

 

Thanks,

 

Chris

 

  

 

> Date: Wed, 20 May 2009 15:50:09 -0700

> From: rlbpantera at earthlink.net

> To: DeTomaso at realbig.com

> Subject: Re: [DeTomaso] battery recommendation

> 

> I agree with Ralph Granchelli post on May 17: Optima's suck. My
wife's 

> Lexus SC420 has gone through 2 of them (red tops) in less than 4
years. 

> It sits for a week or more at a time and before I got a tender
would get 

> drawn down to dead once in a while. I thought they were supposed
to do 

> better than most against that but this is not the case. The last
one 

> lasted 1.5 years and got killed on the tender when the tender
couldn't 

> keep up with the trunk light drain.

> 

> Zonkey has had an Odyssey PC1200 (same one) for 7 years (I won it
in the 

> Vegas raffel). It's been run to zero a number of times and still
works 

> fine. So I decided to bite the bullet ($$$) and put one in the
Lexus.

> 

> It turns out that the Sears Platinum is an Odyssey (both made by 

> Enersys). I discovered this while searching for a good price on an
  

> Odyssey. The Sears Platinum P-1 (Group size 34) is the same as the
  

> Odyssey PC1500T (1500 peak cranking amps, 62 amp hours). It is
$189. If 

> you want the ultimate cranking machine, the Marine Platinum PM-1
is a 

> PC2150S and rated at 2150 amps/ 95 ah (and weighs 75 lbs!). If
that 

> can't start your car, nothing will! It costs $249 (but now is $10
off, 

> $239).

> 

> Richard

> 

> -- 

> ----- 

> Sincerely, Richard Barkley

> 

> To Ski or not to Ski, that is the question!

> 

> Richard Barkley (310) 373-6695 (home)

> E-mail: rlbpantera <atsign> earthlink.net

> ZONKEY'S home page: http://home.earthlink.net/~rlbpantera

> Mammoth Lakes Vacation Condo: 2BR+loft/3Bath - Horizons 4 #186
(760) 934-6758

> Condo web address: http://home.earthlink.net/~rbarkley

> 

> _______________________________________________

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-- 
----- 
Sincerely, Richard Barkley

To Ski or not to Ski, that is the question!

Richard Barkley (310) 373-6695 (home)
E-mail:  rlbpantera <atsign> earthlink.net
ZONKEY'S home page: http://home.earthlink.net/~rlbpantera
Mammoth Lakes Vacation Condo: 2BR+loft/3Bath - Horizons 4 #186 (760) 934-6758
Condo web address: http://home.earthlink.net/~rbarkley



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