[ctrlz]

Originally Posted by p47dman

Yes, but a reading of 2 amps would be way too much. And a 60 amp hour battery would be dead in 30 hours.

This post has a neat little chart showing how long it might take to drain a battery with various parasitic loads.
https://www.camaro6.com/forums/showp...4&postcount=23

Some of those low amp chargers are fine for maintaining a car battery, but not necessarily recharging one. They can handle a motorcycle battery. Read the reviews. I have some Nexpeak chargers from amazon which work great on my jet skis. 1.75 amp peak.

[p47dman]

60 divided by 2 = what??

l find it very sad that some with no real world experience rely on the internet for everything.
Second, chart is wrong.

[ctrlz]

Originally Posted by p47dman

Second, chart is wrong.

Below is from the 2017 Camaro repair manual.
The main parasitic drain that is "always on" is OnStar, which is reported as < 40 mA
We are 17 posts in and nothing from the OP.

The battery run down time will vary depending on the battery's reserve capacity. If the reserve
capacity is higher, then the battery run down time may be longer. If the reserve capacity is
lower, then the battery run down time may be shorter. The graph below indicates roughly how
many days a 690 cold cranking amperage battery with a 110 min reserve capacity starting at
80% state of charge will last with a constant current draw until it reaches 50% state of charge.
Differences in battery reserve capacity and temperature will affect the results.
Current Drain Days
25 mA 33
50 mA 16.5
75 mA 11
100 mA 8.25
250 mA 3.3
500 mA 1.65
750 mA 1
1 A 0.8
2 A 0.4

[p47dman]

OMG

do the math for yourself!

[HypeBlueZL1]

I replaced my original AC Delco battery in my 2017 Camaro today. It was still starting the car but I figured after 8 years it was time. Changing batteries on these cars is kind of a pain and not something you want to do away from your garage and tools. I parked my car every winter and just disconnected the negative battery cable. Never had an issue with it.

[p47dman]

BlueZL1, what you did is fine. I have seen a lot will use a tender over storage with many different ways of hooking it up. Myself, I am lucky to have room at home to store her, this was her first winter, ha ha. We had almost no snow and only got below zero a couple of nights, I had her out in Feb, . Hence, I did not do anything for battery protection. Will have to rethink that for next winter, whenever that may happen.

[Gunkk]

Originally Posted by Uncle

Any help / advising is greatly appreciated!

My advice having gone through something like this on my 2017 back in 2020 (coincidently right around 3 years of ownership):

1. Use an AGM rated battery tender.
2. Disconnect the battery from the car during winter storage and leave the tender connected to the battery and only the battery. Do not use the jump posts under the hood (I know some do as getting at the battery is a PITA on the coupe, but I do not recommend this for reasons below).
3. Do not periodically start and run the car during winter storage. Does more harm than good. Plenty of discussion on this in the winter-prep threads.
4. The charging systems on our cars tend to under-charge the battery due to the designed-in conservative AGM battery management code trying not to overheat and overcharge the battery. So the battery can slowly lose charge over several months, even when daily driving. This can fool the owner into prematurely changing an otherwise good battery that just needs to be charged. Some say that tricking the system into high power state by running the HVAC and/or turning on the headlights during daytime driving can mitigate this.
5. Then if the battery then dies from said undercharging and/or sitting with a dark current of 20mA for a few weeks, some of the modules in the car can throw false codes as they slowly drop under critical "sleep state" voltage, and then after the jump start they get stuck in high-power "illuminate CEL" state that then becomes a parasitic drain unless the car is put into service mode and the codes are cleared.
6. I am one such fool who after seeing the battery quickly die after going through this wrongly though it was the battery. Only to then learn after a brand new AGM was installed I still had a parasitic drain due to the trouble-state of one or more modules. When my car gets into this state, I can see the backlight of the center console display won't turn off when the rest of the car goes to sleep -- a dead giveaway. After clearing codes this all goes away and the car is fine.
7. So now having learned all these lessons and now slap my CTEX MXS 5.0 on all my cars every 6 months as a preventative maintenance. When it's not doing that, it's on The Mistress with her battery disconnected using one of these.
8. No issues for me since, but I must put the car into service mode upon power reconnection prior to first restart or the modules do not play nice after a long nap. I chalk it up to 1st model year convertible software & modules being a bit twitchy in this regard.

Your mileage, as they say, may vary.

[arpad_m]

Gunkk, why do you not recommend hooking the battery tender to the underhood posts? I must have missed those "upcoming" reasons your mentioned in your point 1.

Incidentally, I've never had any problems using the underhood terminals, and really try to avoid disconnecting the battery, which resets a couple of things that I then need to set back up again.

Originally Posted by Gunkk

My advice having gone through something like this on my 2017 back in 2020 (coincidently right around 3 years of ownership):

1. Use an AGM rated battery tender.
2. Disconnect the battery from the car during winter storage and leave the tender connected to the battery and only the battery. Do not use the jump posts under the hood (I know some do as getting at the battery is a PITA on the coupe, but I do not recommend this for reasons below).
3. Do not periodically start and run the car during winter storage. Does more harm than good. Plenty of discussion on this in the winter-prep threads.
4. The charging systems on our cars tend to under-charge the battery due to the designed-in conservative AGM battery management code trying not to overheat and overcharge the battery. So the battery can slowly lose charge over several months, even when daily driving. This can fool the owner into prematurely changing an otherwise good battery that just needs to be charged. Some say that tricking the system into high power state by running the HVAC and/or turning on the headlights during daytime driving can mitigate this.
5. Then if the battery then dies from said undercharging and/or sitting with a dark current of 20mA for a few weeks, some of the modules in the car can throw false codes as they slowly drop under critical "sleep state" voltage, and then after the jump start they get stuck in high-power "illuminate CEL" state that then becomes a parasitic drain unless the car is put into service mode and the codes are cleared.
6. I am one such fool who after seeing the battery quickly die after going through this wrongly though it was the battery. Only to then learn after a brand new AGM was installed I still had a parasitic drain due to the trouble-state of one or more modules. When my car gets into this state, I can see the backlight of the center console display won't turn off when the rest of the car goes to sleep -- a dead giveaway. After clearing codes this all goes away and the car is fine.
7. So now having learned all these lessons and now slap my CTEX MXS 5.0 on all my cars every 6 months as a preventative maintenance. When it's not doing that, it's on The Mistress with her battery disconnected using one of these.
8. No issues for me since, but I must put the car into service mode upon power reconnection prior to first restart or the modules do not play nice after a long nap. I chalk it up to 1st model year convertible software & modules being a bit twitchy in this regard.

Your mileage, as they say, may vary.

[Gunkk]

Originally Posted by arpad_m

Gunkk, why do you not recommend hooking the battery tender to the underhood posts? I must have missed those "upcoming" reasons your mentioned in your point 1.

Incidentally, I've never had any problems using the underhood terminals, and really try to avoid disconnecting the battery, which resets a couple of things that I then need to set back up again.

TL/DR: if your tender works on your car's jump posts without issue, then you can ignore the rest of this post

A couple reasons. All of them might be related to how the CTEK interacts with my "special" car, and how my car behaves with low and intermittent voltage, or they might be common with more than one type of charger.

First one is Parasitic draw (and even deep sleep state of the modules drawing 20mA or so) which may be seen by the tender as a battery fault, resulting in the tender thinking that the battery has an internal short. This happened with my CTEK MXS 5.0 when the battery was connected to the car while the modules were throwing codes. The CTEK shuts off with a red light (stopping the charge), preventing the battery from being able to be recharged. Can't get the car into service mode with a dead battery to clear codes + can't charge the battery on the jump terminals = have to disconnect the battery in order to charge the battery.

Second one (I did not mention in my prior post) is Desulfation may not perform as desired with the electrical compliance in the entire system softening the edges of the pulses. And the extended desulfation pulsing from zero to 14+ volts from the CTEK 5-10 times per second probably isn't good for the car's electronics. How do I know? Just suspicion based on the behavior: Instead of stopping the pulses after about 5-10 seconds or so when connected directly to the battery with battery disconnected from the car, the desulfation pulse cycle doesn't stop when connected to the jump posts. So whatever signal it's looking for to stop and proceed to the next step in the charge cycle, it's not seeing it while connected to the battery posts. I'd prefer my electronics not be thrashed indefinitely by my tender if the house power blinks out and the tender resets, so I do what I do and recommend the same to others based on what I see.

[SS_Don]

I have used a NOCO GENIUS 5 for a couple of years connecting to the posts under the hood during the winter without any issues.

[arpad_m]

Originally Posted by Gunkk

TL/DR: if your tender works on your car's jump posts without issue, then you can ignore the rest of this post

A couple reasons. All of them might be related to how the CTEK interacts with my "special" car, and how my car behaves with low and intermittent voltage, or they might be common with more than one type of charger.

Got it, got it, thank you for the details.

The CTEK looks like a fairly basic unit indeed, I have an OptiMate 6 that works like a charm and charges the battery properly.