Battery problems with CS

Sounds like a heavy system draw.

Pretty simple to diagnose with some minor skills. Your taking within the range of Milli-amps though, so some electrical diagnostic equipment will be required.

Often times it will be related to a relay, or stereo equipment. I remember a factory amp that stayed on even after the car was shut down. We simply checked amperage (draw) at the battery and then pulled each fuse out of the fuse panel until we saw the draw drop significantly. Then we knew what circuit to explore.

Takes time but you will get to the bottom of it.

 

Sounds like you may need a new battery. Can be had a pep boys. Or at the dealer for $700.

 

Jason - My dealer (scottsdale Ferrari) only charged me $139.99 for an Interstate MTP-91 battery. Yes, it was more like ~110 at pep boys et al IIRC.

OP - yup, if the new battery is still having the issue...well, its likely something else (how's that for insight!)

 

Radio & amp are just examples. Your CS will still have dome lights, digital clock, alarm system, electric pumps, electric fans, dozens of relays. Your going to have to think out of the box.

 

Or in the box.. fuse box that is.

 

you say bare bones... what about the alarm. the various computers / memories etc that must be kept alive

as has been already mentioned do an audit of the current draw with the engine off, it will show how much power is being used... something could be malfunctioning

what are the specs of your battery...what is the reserve capacity of your current battery ? a low RC means it runs out of power quickly

a battery designed / skewed mainly for starting does a great job at starting, but goes flat quickly even with a small constant drain... it has nothing to do with the type of battery construction ( wet / gel / AGM )

a larger RC spec will not go flat as soon, ultimately it's the constant drain and occasional use that allow it to go flat... use a battery charger / maintainer... photos on this site show many cars hooked up to their chargers

I looked up the Interstate MTP-91 battery specs, spec given were skewed for a starting battery, ( good for starting ) but did not disclose any other details...
judging by low battery weight and small physical size I would guess that it does not have a good RC capacity. BTW it is a standard flooded cell (wet ) A typical power graph for this type of battery shows a flat line ( good power ) for a short time, then the line falls straight down where it looks like a cliff. I'll try to get in touch with Interstate batteries for more details.

 

My dealer quoted me a lot more. I'd have gotten it from the dealer too at that price.

 

using the 74Ah value, that battery would be discharged in 3 days if the rate of drain is 1 ampere ( that would be a very high rate to keep memories up ) actual rate of discharge should be a small fraction of that. To better understand what is going on in your car is to verify the rate of discharge, something may be causing an abnormal drain. It's possible the battery is not getting a full charge with each use. Need to check charging system, regulators can go out of spec. limiting the amount of charge or the car is not operated long enough for a full charge. In the short term, start using the battery charger, Ferrari supplies one. It's an acknowledgment that power is being used. It will insure that the battery is full each time, it may be all that you need to do with the way you use the car.

 

It is an acknowledgement that most Ferraris aren't driven enough and sufficiently frequently Current draw when parked is probably similar to other cars. Drive "any" car as little as most Ferraris are, and they will also kill the battery. Any of my cars not driven at least 3 days a week is on battery tender, no discrimination against marks

Though, full "discharge" in 3 days obviously isn't right.

Jes

 

I spent last winter chasing a high current draw/dead battery. Finally found it. An easy test if your car has the battery disconnect switch would be switch it off and then try starting the car three days later. Another thing to do is pull the battery out and have a battery store test it. My problem turned out to be the front hood, if it is not latched, there is a 500ma current draw because a system doesn't turn off. The factory charger harness has 3-4 wires and there is a relay in one of the 7-10 fuse panels that bypasses the the large battey disconnect switch located in the trunk (at least on the 360). I found my solution after: replacing the battery, bypassing all the switches on the driver's door so I could access the fuse panels, pulling each fuse and checking current draw.

Some other things that might cause the current draw are leaky diodes in the alternator, bad alarm system, windows that are not parking properly.

So just be patient, work through the check list. Normal draw is about 30 ma, if I remember corrently. FWIW

Jeff Pintler
89 348tb, 86tr, 99 360 3pedal