General > General Technical Chat
Murphy’s Law with my OBD2 reader
edy:
--- Quote from: sokoloff on January 05, 2023, 03:55:54 pm ---$88 in 2012 is $114 today.
Even modest annual inflation accumulated over a decade ends up being quite noticeable.
--- End quote ---
Wow! I can’t believe it. I guess I’ve been living in a cave. It’s not even 10 years, that’s crazy. I have to check if my income has kept up but somehow I don’t think so. :scared:
So a bit of history. The car is 2011 (bought it spring 2011) so you may be wondering why I bought a battery in Dec 2012 which is not even 2 years after I bought the new car. Surely the original battery was good? Yes it was. However around that time my son needed a CPAP machine and some other medical devices so I bought a battery and kept it trickle-charged so in case of a power-failure we would have something to run his equipment (I also have an DC/AC inverter).
Turns out that a few years later, not sure when, my car’s original battery finally died. When I bought the extra battery for my son’s CPAP I made sure it would fit my car because eventually I knew I could have a spare. So when my original car battery died I put in this “backup” which was the emergency use one for the CPAP in case of power-failure. Meanwhile I didn’t buy another battery because by then my son grew old enough that he could manage and the CPAP machine wasn’t critical anymore. That also is why I got a regular car battery and not one of those deep discharge marine batteries with thicker lead plates that can be discharged and depleted further (which would last longer and not get damaged and may make more sense for power-failure inverter use cases).
So while technically the battery is about 10 years old now, it’s really only been in the car (and under weather and other stresses) for much less than that but I can’t tell how long. 4-5 years? 7 years? I have no idea.
As can be seen by the attached photo the battery managed to complete the charge before 10am this morning. When I checked it while it was charging and seconds after I pulled the charge clips off the terminals it was up around 12.89V but dropping. Once it got to the “complete” and left it like that for a few hours (it’s now 1pm) I just measured it and it’s a steady 12.66V right now. I assume the charger stopped supplying current and so the battery has settled. I’ll leave the battery disconnected completely from the charger and check the voltage again at the end of the workday before I put it back into the vehicle for the drive home, probably closer to 6-7pm.
[ADDENDUM 1: Strangely enough I just measured it now, closer to 2pm and it’s at 13.08V. :-// I’ll measure it every hour, I don’t know why it went up more since I disconnected it from the charger. Did it have some “momentum” going for ions still exchanging internally or was my meter messed up or not contacting the terminals properly before ??]
[ADDENDUM 2: Ok, so my meter is a cheap piece of garbage. When I have it on 20V range it tells me 13.06V, when I put it to 200V range it reads 19V and when I put it on 500V range it alternates between 12 and 13V reading. I don’t trust the 200V range setting at all. Seems the 20 and 500 ranges are closer to being accurate but anyways if I just keep reading on the 20V range (the next lower one is only 2V) at least I figure the comparison of values to see if it is falling will be ok even if absolute value is completely off. Until I get home I won’t have a better meter].
[ADDENDUM 3: Since nothing posted after this reply I figure I’d put in another addendum. It’s now close to 7pm and measured it again and it is 12.63V. I don’t know what was going on with the multimeter before but clearly something was not right for it to measure >13V. Anyways, I’ll keep an eye on things and if I see things not stable I’ll just get another battery, but for now this one seems to be working well enough].
[ADDENDUM 4: Tried multimeter again, showing 13.08V. |O I don’t know what’s going on with it. So last time it measured 12.63, before that 13.06, I am not doing anything different.]
edy:
Hey everyone,
It's been about 5 days and more testing on the battery. It cranks the car for a day or two, then refuses to start the car. I've brought the battery into an auto repair shop twice for testing on special machines, both times they are telling me cold-crank amps is in the high 200's to mid 300's (depending on it's state of charge) and that the battery is still OK and doesn't need to be changed (it's rated at 500).
I've checked drain on battery when car off and parked, doors locked and all lights off by checking current using multimeter across negative battery terminal to negative connector lead and initially it jumps up to a couple A (likely computer and other components turning on) and then within a few seconds drops down to 0.1A or even less. So I don't believe anything is draining the battery in the car.
Also, last night charged up battery and immediately after disconnecting from charger it was 12.8V. After a few minutes it settled to 12.6V. I then put it in the car, connected it and left it overnight. In the morning the battery was 12.1V but I was able to start the car. Drove to drop of kids at school and then to the mechanic, maybe 30 minutes driving.... When I got to the mechanic the battery was up around 12.4-12.5V. They tested it again on the machine, they said battery was ok. They used a "fancy" machine that checks individual cells also.
At this point, I'm going to do the following to try and narrow down the flaw. It could either be battery, alternator not charging it, or some phantom power draw when car is off. I checked battery leads when car is running (with battery disconnected) to see what alternator is putting out and it was measuring 14.2-14.4V so alternator is delivering charge so I can't imagine it's that.
So trouble-shooting steps:
1. disconnect battery when car is parked and see if it still drains it
- if my voltage drops while it is just sitting there doing nothing, maybe battery has some internal issue and for whatever reason all the machines are erroneously claiming it's still good
2. connect battery across multimeter to keep eye on amps, then start pulling fuses one by one and seeing if there is a current draw change. However, as I mentioned normally current draw is very low even with all fuses in so I can't see that being the case.
3. alternator charge not good enough, even if voltage reading is high on terminals? could it be encountering some other issue not providing enough current to the battery?
And down the rabbit hole we go.... |O
bdunham7:
How many miles on your CRV? Does it rattle a bit when started cold? Timing chain wear or other related parts are a common issue causing P0341 on higher mileage K24 engines. If you are using oil, keeping it full is a must--you should check it every fueling, just like the old days. The oil consumption may vary drastically under different conditions. Also, good 5W30 oil won't kill your old CRV engine--even in cold weather--and it may or may not help with consumption and the other issues.
PlainName:
My money is on the battery - needs replacing.
If it were a current draw then the battery would be flat (and buggered), but it's not.
AVGresponding:
I reread your OP just to check a few things. This sounds very much like a bad connection, if the battery tests at the garages are to be believed, and I see no reason not to.
When you say you checked for loose connections, did you check the main earth, and did you check the connections into the main fuse board which are usually not easily accessed without some disassembly?
The main earth can appear to be well terminated, but the cable can be badly corroded and giving poor or intermittent connection. The main fuse boards on cars this modern can be problematical, there's so much controlled through relays by the various body control modules. My drivers side dipped beam is out atm, lamp is fine, wiring is fine, bloody relay in the main fuse board is the problem. One common enough issue is relay contacts welding closed, so lights can't be turned off :palm:
Anyway, you could easily have a problem in the fuse/relay board. It's worth reseating everything as a first attempt :-//
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