1999 V70T5M56 Elizabeth Voltage Bus problem [Old battery on last legs] Topic is solved

Post by **abscate** » 07 Dec 2019, 11:22

Documenting a problem

Prewarning: we had a heavy snow here and with lots of slush I noticed that if STC operated for more than a few seconds, I would get an ABS light. I also noticed if Imrookie-clutched it and let the revs go below 500 rpm, I would get the same fault. After a few seconds of running the fau;ts would clear.

I drove the car to Boston with no faults two days later

On the way home, if I flashed high beams to guide a truck back in, I got the ABS fault, then just headlights did the same thing. Turning lights off , then faults cleared again in a few seconds

I made it home just before dusk wth lights off.

I measured 12.5 v at battery at 0 Celsius

I put the battery on charger overnight, and now have driven it for a week with no faults

Battery history is near end of life . 6 years and 105k miles in service

Alternator is relatively new, 2 years 40k miles

Video of failure recorded below.

One minute video of fault at at speed

Post by **volvolugnut** » 07 Dec 2019, 17:34

You have received full value from that battery. Time to replace. Thanks for good documentation of poor voltage faults.

volvolugnut

Post by **abscate** » 07 Dec 2019, 18:12

I’m going to try top it off each weekend and nurse it through winter. It will be fine in summer.

A real grownup will just replace it now , of course

tmm657 · Post by **tmm657** » 20 Dec 2019, 23:31

Don’t know where you live, but Rural King has 60 month batteries for 55-60 bucks for most sizes and the last I knew they were relabeled Exides. Check whatever farm supply stores you have.

Post by **abscate** » 21 Dec 2019, 01:48

A real grownup would just replace it of course. Whenever I take a dollar out of my pocket, George Washington blinks for all the light, though.

It’s a good learning lesson on how a battery can be good enough to start a car at 20F, but not be good enough to run an electronic era car reliably. She is starting and running fine three weeks later, after a solid charge.

Post by **volvolugnut** » 21 Dec 2019, 09:12

We should make it rule number 1 of late model Volvo ownership: The battery voltage must be sufficient to keep electronics happy. It is not 1960 when battery test is cold starting capability.
volvolugnut

Post by **abscate** » 10 Jan 2020, 03:53

The same battery is cranking and running fine in 20 F weather, so I’m trying to get one last winter out of it. It will get a good charge on weekends to keep it happy, then get relegated to boat duty where it will just light some LEDs

Post by **volvolugnut** » 10 Jan 2020, 10:26

You make a good point here. There are batteries and BATTERIES. We used to use batteries until they would not crank the car any longer. (Side note: I once had a battery explode with a hole in the case. It measured about 10 volts, but would start and run 1964 Ford truck.)
Batteries now are good for boat lights and old cars without extensive computer systems.
BATTERIES are needed for cars with major computer systems that require fully charged voltage just to keep the vehicle running well. When BATTERIES get old they degrade to batteries.
volvolugnut

Post by **abscate** » 10 Jan 2020, 12:04

It is not 1960 when battery test is cold starting capability.

This has been registered as official MVS lore (tm)

Thanks, volvolugnut

Post by **abscate** » 15 May 2020, 01:53

Still running that old battery. With Corona shut down, I’m putting all the cars on charger every 2-3 weeks

It’s showing 12.2 Volts at 75F, so a bit less than 50% capacity by voltage, I’m guessing Current capacity is even less