!!CAUTION!! when jump starting your Gen II

[97 B/W GTS]

Back in March I had trouble starting my car after a 10 month hibernation.

Hooked up the portable jump starter. Wouldn't start. Put it on "Boost" setting. Nothing.

After lot's of help (especially from Steve-Indy's phone help...thanks!) fiddling with the alarm reset, plugs, fuel pump relay, etc. and still no start, the car was put on a stretcher to Dan Cragin.

Fried PCM.

Why? If I undertstand correctly, since the car sat for so long with no juice, the PCM was totally drained. Using the "boost" just put too much electricity at once for the PCM to handle. Zap! Steve-Indy has heard of this happening to a few other Vipers also. Not really sure if the 'sitting for so long' part has anything to do with it, but the 'boost' definitely did.

Hopefully my expensive mistake will help others.

Lesson? DONT USE THE BOOST ON JUMP CHARGERS. Ideally, charge a dead battery before jump starting.

[Steve-Indy]

I would be interested to hear what the pro's think about this. The few that I know about were ALL GenII's, had tried to charge their battery, then applied a 50 amp to 250 amp "boost-to-start" and were later diagnosed with a "fried" PCM as mentioned above. A neighbor also did the
exact same thing to a 1997 Dodge Dakota with the same results...bring my personally observed total to 6 "fried" PCM's (5 Vipers).

Chance observations?? Did the PCM's "die" before of after the interventions??

Please jump in, Professionals !!

[Billy Coons]

When I replaced the battery in my 03 SRT-10 and mentioned it to the local Viper tech, he told me never to let the battery discharge completely if I could help it (have a trickle cahrger now) and if it did, pull it out and charge it seperately from the car. Said he had another guy that fried his GEN3's computer trying to charge it in the car after sitting over the winter.

[dave6666]

I'll jump in on the level of professional intelligence. With what seems like frequent posts etc about batteries going bad over winter or other hibernation periods, wouldn't the smart thing to do be to remove the battery and store in a warm area with a tender?

I just fail to understand how 10 months of downtime drains the PCM any more dead than the Wizard mandated approach of resetting the PCM by shorting out the positive battery cable to the chassis. Which I have done on my '01 many times. Always fires right back up. No alarm reset needed, no key fob issues. Nothing.

We're talking solid state electronics. Time is not their enemy. Circuit chips, capacitors and resistors do not go bad when power is removed.

But I definitely agree that the boost charger thing is a bad idea.

Just take care of your battery is my short opinion.

[Viper Specialty]

It is not the amperage that causes a problem, it is the voltage and type of current. The Viper PCM can be applied 10,000 amps at 12 volts DC, and it will not be damaged. The PCM, like most electrical devices, is internally regulated and contains components which resist the free-flow of electrons which would normally induce a "dead short". The device will only draw as much current as needed.

Likely, there is a problem with the AC/DC rectifier diode of these "boost" units, and it is bleeding through AC into the system, which is causing the damage. Normally, the battery would filter some of this out if fully charged, though when the battery is flat-lined/damaged, it is unable to do so.

[99 R/T 10]

If you need a PCM, PM me.

[Chopper]

Battery Tender.Plug it in then forget about it.

[dave6666]

Originally Posted by Chopper

Battery Tender.Plug it in then forget about it.

A freezing battery is a freezing battery... No bueno!

[Madduc]

A fully charged battery will not freeze.

[RTTTTed]

Originally Posted by Madduc

A fully charged battery will not freeze.

Yah, they will. That's why I sell "Battery Blankets". Even around -20 many batteries don'w work well. Once you get to -40 not many batteries work at all.

Ted

Ted

[Madduc]

"Frozen" and losing its cranking ability due to very cold temps are different. Yes batteries lose CCA the colder it gets, and that is compounded by the engine being even harder to crank over. I was talking the battery is frozen solid.

[dave6666]

Originally Posted by Madduc

"Frozen" and losing its cranking ability due to very cold temps are different. Yes batteries lose CCA the colder it gets, and that is compounded by the engine being even harder to crank over. I was talking the battery is frozen solid.

As I have worked in the chemical industry for the past 27 years now, and have access to more PhD chemists than is really necessary to have access to, I asked about the freezing point of H2SO4. Depending on the concentration of battery acid, the freezing point may not be a "practical" temperature. Like maybe minus 100 deg F or so. But trust me, sulfuric acid can and will freeze solid at any concentration.

[Kenneth Krieger]

Freeze a battery? You've got to be kidding? Oops....sorry, I live in Phoenix....no frozen batteries here! However.....we have HEAT as you know and will fry a battery in most instances. The average battery lasts about 18 months in the Phoenix heat....UNLESS....you have a battery tender! On my Gen 1 the battery lasted 9 years and was going strong when the car was totaled. I hook up a battery tender to all my cars and haven't replaced a battery in years! Get the battery tender, and yes in a cold climate, if you are storing the car for months at a time....take the battery out and keep it warm while on the tender....it will last a long, long time!

[AviP]

If there is some juice, you could always try push starting it. It has worked for me when the battery is just below normal starting voltage.

[Madduc]

Well if it's -100f out, I'm not gonna drive the viper, or even go outside myself!