[wwiiavfan]

I put a 1.5 amp Schumacher maintainer on the underhood terminals on my ‘17 SS the first winter I had it (2017-2018). In heated but partially insulated garage in Wisconsin. Started fine in the spring but battery died within a month. Ended up being a bad battery (even though it tested perfectly at the dealer.)
Since then I’ve removed my battery in the winter (only takes 5 min) and brought it in my basement on the same maintainer with no issues.

[tommcd24]

Originally Posted by Chutzpah

I’d say your charger is a bit underpowered for the application. I use a NOCO 3.5A unit, in a heated garage. I probably wouldn’t go any smaller than what I have now (just based on how long it could take to fully charge a discharged battery). I use the terminals under the hood.

I think I’m leaning that way also, particularly since I don’t want to leave it connected all winter. I’ll see what my 2amp Noco reads in the morning, but I’ll probably be ordering a 5amp unit tomorrow.

[Gunkk]

Originally Posted by tommcd24

Does this seem legit that my battery could truly have drained that much?

Yes. Our cars will draw ~20mA or so while asleep. 70 Amp-hours / 0.02A = 20 weeks by the numbers, but in reality you're more likely to get only half that before the battery can't start the car. So yeah 10-12 weeks will usually kill a completely charged battery.

Re-charging by driving doesn't work well because AGM. Not like the old flooded cells. You really need to get a good AGM charger/tender on it for a couple days.

Is my NOCO underpowered or do the front battery terminals have too much resistance or something for trickle charging?

Probably not, but it might take a week to completely charge a dead battery, or a few days to top up a half-dead one. My 5 amp Ctek needs about 48 hrs to charge a dead AGM battery. About half that for a regular flooded cell. So your 2 amp NOCO would need 250% that time... close to a full week for a Camaro.

In the meantime, if anyone has "been there, done that" and has pointers for me, I'd appreciate it.

My Ctek doesn't play well with the modules in the car. If one of the modules is awake and pulling 100-250mA during the "health check" cycle, the CTEK will see the high drain and error out, thinking the battery has a short. You can watch the car go to sleep by measuring voltage drop across the fuses in the front engine bay fuse box using a chart. I've seen some odd sleep/wakeup behavior with the modules in my car when there's a stored CEL, and your remote unlock Chevy app can obviously also wake up the car. Using the Ctek on the front posts seemed to want to trigger more weirdness. Might be the desulfate cycle, might not.

I wasn't interested in troubleshooting all of that BS, so I got one of these old-school battery disconnects. And I disconnect the car from the battery while the tender is clamped to the battery. Just have to lay a towel over the latch to keep the trunk ajar so I can get back in the car without having to take apart the door handle. The vert's trunk configuration makes access to the battery terminals a breeze. No wrestling with trunk interior panels required. Disconnects are not for everyone, but the Ctek works just fine with the switch. The Ctek's dual mode is also good for the 3 other family cars without AGM batteries. It's surprising sometimes how a daily driver battery can drain down after a few weeks of nothing but a few <5 min trips.

[tommcd24]

Update: checked on the NOCO this morning and the battery was up to a full charge and in maintenance mode. Strange that the first 12-hours left it at 25% and the second 12-hours (actually about 14 hours) finished the process.

I have read that these new generation NOCO Genius chargers have a desulfitation process they run through, so maybe that takes a good chunk of the first 12-hours.

I'll probably hook it back up in a week or 10-days to guage how long it takes from start to finish at that point.

[ember1205]

Originally Posted by tommcd24

Question for those of you who live in cold climates regarding trickle-charging/maintaing the battery. I've never been one to use an always plugged in battery tender, instead opting to connect a charger/maintainer once a month or so instead.

I just got my 2SS in Dec. and it's been parked in my garage since. I did start it up on Christmas Day for the family and let it idle for about 20-minutes, but otherwise have avoided starting it, since I won't be driving it until closer to spring.

So, car's been parked since mid-December in a garage that is insulated, but not heated. As an example, if it's 0*F outside, it is normally 20*F in the garage. We've had a number of sub-zero degree days lately, including a 72-hour stretch last week and another cold snap coming up. So trying to be proactive, I put my NOCO 2-amp charger/maintainer on yesterday for about 12 hours expecting that would top it off and report a full charge state. When I checked it around 10pm last night it had not progressed past the 25% indicator, which surprised me.

In comparison, I can fully charge/maintain my Harley battery in 4-6 hours, which I do about once a month or so. Obviously the Camaro's battery is much larger than my Harley's, but I fully expected that 12-hours would have at least progressed to the 50% indicator (the NOCO has four lights, each roughly corresponding to 25% of capacity).

Does this seem legit that my battery could truly have drained that much? When I opened the door, the interior lights all came on, the window did it's normal 1/2" downstroke (convertible), and everything seemed "normal" or at least as normal as I can tell since I've driven the car a total of 30 miles or so at this point... I do understand it would take much less juice from the battery for the lights than starting it, etc. but all of the "dome lights", accent trim lights (2SS), illuminate door sills, etc. lit up normally.

Is my NOCO underpowered or do the front battery terminals have too much resistance or something for trickle charging? I've read that many people use a 4-amp maintainer, which is what GM sells, maybe 2-amp is just too low?
The other question I have, and my next step, is to move the NOCO to connect directly to the battery in the trunk and see if that changes anything.

In the meantime, if anyone has "been there, done that" and has pointers for me, I'd appreciate it.

I have a couple of different types of tenders... One is a "Battery Tender" brand and the entirety of it plugs directly into the wall. This is a low wattage unit that took over two full days to fully top off a battery in a Honda Accord that had been sitting outside for three months in the winter. The charge level was down a bit from not being driven, but it did start on its own with some slowed cranking. I pulled it into the garage, plugged it in, and left it for 2.5 days until it was finally topped off.

I also have the Schneider Electric units that are a bit higher wattage and will top off my Camaro and hold it there nicely.

I have a solar-powered Battery Tender unit that I'm considering trying to connect to the Camaro while it's in storage to at least see where it shows the battery currently. Doubt it would actually be able to put any charge on it.

Originally Posted by Rock-It Man

I can't understand why the OP waited until it was below freezing to attach a battery tender.

The battery tender should be running full time as soon as the car goes into storage. Among other things, it protects the battery from damage due to freezing temperatures. Possibly the OP's battery is already seriously damaged.

Freezing temps will not do damage a battery unless the charge level of the battery is sufficiently reduced. How many students park their cars in the lots at college in cold weather states and leave them there for weeks upon weeks without being driven? And how many of them have battery damage as a result?

Originally Posted by Gunkk

Yes. Our cars will draw ~20mA or so while asleep. 70 Amp-hours / 0.02A = 20 weeks by the numbers, but in reality you're more likely to get only half that before the battery can't start the car. So yeah 10-12 weeks will usually kill a completely charged battery.

Maybe, maybe not. Started and drove my car in January 2021 as I had to bring it to the dealership to be looked at by the local rep. Drove it back to storage after the visit and parked it there until early May. Well over the 12 weeks you mentioned, and my car started right up. Cold storage, no ability to connect a charger/tender. And it wasn't in transport mode.

[JSH]

The thought of charging mine has never crossed my mind. Just drive or crank it occasionally and save the dough.

Originally Posted by tommcd24

Question for those of you who live in cold climates regarding trickle-charging/maintaing the battery. I've never been one to use an always plugged in battery tender, instead opting to connect a charger/maintainer once a month or so instead.

I just got my 2SS in Dec. and it's been parked in my garage since. I did start it up on Christmas Day for the family and let it idle for about 20-minutes, but otherwise have avoided starting it, since I won't be driving it until closer to spring.

So, car's been parked since mid-December in a garage that is insulated, but not heated. As an example, if it's 0*F outside, it is normally 20*F in the garage. We've had a number of sub-zero degree days lately, including a 72-hour stretch last week and another cold snap coming up. So trying to be proactive, I put my NOCO 2-amp charger/maintainer on yesterday for about 12 hours expecting that would top it off and report a full charge state. When I checked it around 10pm last night it had not progressed past the 25% indicator, which surprised me.

In comparison, I can fully charge/maintain my Harley battery in 4-6 hours, which I do about once a month or so. Obviously the Camaro's battery is much larger than my Harley's, but I fully expected that 12-hours would have at least progressed to the 50% indicator (the NOCO has four lights, each roughly corresponding to 25% of capacity).

Does this seem legit that my battery could truly have drained that much? When I opened the door, the interior lights all came on, the window did it's normal 1/2" downstroke (convertible), and everything seemed "normal" or at least as normal as I can tell since I've driven the car a total of 30 miles or so at this point... I do understand it would take much less juice from the battery for the lights than starting it, etc. but all of the "dome lights", accent trim lights (2SS), illuminate door sills, etc. lit up normally.

Is my NOCO underpowered or do the front battery terminals have too much resistance or something for trickle charging? I've read that many people use a 4-amp maintainer, which is what GM sells, maybe 2-amp is just too low?
The other question I have, and my next step, is to move the NOCO to connect directly to the battery in the trunk and see if that changes anything.

In the meantime, if anyone has "been there, done that" and has pointers for me, I'd appreciate it.

Link to my unit if it helps with the underpowered question: https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

[ctrlz]

Originally Posted by tommcd24

Update: checked on the NOCO this morning and the battery was up to a full charge and in maintenance mode. Strange that the first 12-hours left it at 25% and the second 12-hours (actually about 14 hours) finished the process.

I think maybe you had a bad connection at first.
I don't think your NOCO charger is undersized for what you are trying to do.

[tommcd24]

Originally Posted by ctrlz

I think maybe you had a bad connection at first.
I don't think your NOCO charger is undersized for what you are trying to do.

Could be. That positive terminal under the red cap is pretty thin. The first time I had the jaws standing up. When I re-connected it last night I put the jaws sideways on the positive terminal. Think of it like biting with the molars instead of the front teeth.

Should work either way, but maybe the side teeth have a better "bite".

[ctrlz]

Originally Posted by tommcd24

Should work either way, but maybe the side teeth have a better "bite".

I pretty much always jiggle those clamps, even if attaching to the battery directly. Surface corrosion or some other contaminant is often present.

[FarmerFran]

Originally Posted by tommcd24

Fair point, but yes, I have it in AGM 12V mode. All my batteries are AGM now, and the unit has some memory function so it starts right up in that mode.

I did some reading on NOCOs site after posting earlier, and noticed that my NOCO 2amp charger is only "rated" for up to 40mah batteries. Our batteries are 70mah, I believe. Not sure if it has some logic that detects the battery capacity and truly fails to work or not? Seems like a trickle charger is a trickle charger is a trickle charger, but with some of the newer logic circuitry maybe that's not the case anymore.

Based on what everyone has said, I'm going to hook it back up when I get home from work and leave it connected overnight and potentially throughout the day tomorrow. If it's still stuck at 25% at that point, I may look to order a NOCO 5amp unit (rated up to 120mah) and/or just connect my full battery charger for a while.

I still have my GM Camaro charger in the garage if you want it. Cheap.

[ember1205]

Originally Posted by FarmerFran

I still have my GM Camaro charger in the garage if you want it. Cheap.

No way, man... That thing causes your engine to blow...


(too soon?)

[FarmerFran]

Originally Posted by ember1205

No way, man... That thing causes your engine to blow...


(too soon?)

[UnknownJinX]

Originally Posted by JSH

The thought of charging mine has never crossed my mind. Just drive or crank it occasionally and save the dough.

Driving a Camaro with summer tires when it's freezing out isn't realistic, and cranking it without actually driving the car can actually drain your battery more than it recharges. It just adds unnecessary wear and tear to the engine and the battery.

That said, here is a thought I am personally going to experiment:

If you have a car outside of the Camaro and a set of jumper cables, could you just use that other car and hook up the jumper cables to the Camaro to charge it occasionally? Obviously, I won't start the Camaro until I decide to actually drive it, but it beats me taking out the battery again to put it on a maintenance charger.

The reason I am doing it this way is because my apartment is stupid and won't let me use the outlet even though there is one right beside where my Camaro is parked, unfortunately. I had the battery out and on a maintenance charger for the last two months, but I forgot an OBD reader in the Camaro and I needed it for something on my winter car. Since the Camaro will only sit for a month more, I thought I'd just hook the battery back up while I am at it.

[ember1205]

Originally Posted by UnknownJinX

Driving a Camaro with summer tires when it's freezing out isn't realistic, and cranking it without actually driving the car can actually drain your battery more than it recharges. It just adds unnecessary wear and tear to the engine and the battery.

That said, here is a thought I am personally going to experiment:

If you have a car outside of the Camaro and a set of jumper cables, could you just use that other car and hook up the jumper cables to the Camaro to charge it occasionally? Obviously, I won't start the Camaro until I decide to actually drive it, but it beats me taking out the battery again to put it on a maintenance charger.

The reason I am doing it this way is because my apartment is stupid and won't let me use the outlet even though there is one right beside where my Camaro is parked, unfortunately. I had the battery out and on a maintenance charger for the last two months, but I forgot an OBD reader in the Camaro and I needed it for something on my winter car. Since the Camaro will only sit for a month more, I thought I'd just hook the battery back up while I am at it.

Can you? I suppose you -could-... Here's why I wouldn't...

The charging system of your Camaro is specifically designed to charge the AGM battery in your car without overcharging it. Does this "other car" have the same design?

Also... You would be connecting to another car that is sitting and idling - not optimal for charging output and the amount of charge it would put into your battery would be just as minimal as if you started the Camaro. The only difference is that you wouldn't have first put the power draw on that battery to start the car in the first place.