CarlosVP

I'm requesting the assistance of the experienced members of the forum. Is this something somebody has used on the past or at least something like this? It looks interesting, but not sure if it could affect anything. Sorry about the dumb question, my C8 is my first high sport car and I want to learn how to keep it on its best shape. I already have the CTEK battery tender

BigF6B

I think you have all you need with your C-Tek charger..I finally did buy one for my '20 C8 and it seems to work fine..My C8 is not a DD so it sometimes sits in the garage for a couple of weeks. It just did since I am in Charlotte county (SW) Florida and we took a beating from Hurricane Ian!..I had to move the car out of the garage to facilitate cleanup and it started right up...Everybody loves gadgets, especially when they have Bluetooth!...

avigar

I agree that your CTEK is sufficient to keep the battery in good condition as long as you use it regularly. No need to add anything else that may throw off the electronics in your C8.

CarlosVP

Thanks to all for your responses. My C8 is my daily driver and I have read some story of people DD their C8 but making short trips and not having enough time for the alternator to charge the battery enough. This looked like a good idea to know when to plug the CTEK, but looks like it will be a pass on it

Bmbl-Bee

If you are daily driving your car, I wouldn't think you would need to put a battery maintainer on it.

Andybump

The CTEK will keep your battery at or near fully charged if you connect it while it is parked in your garage. Mine is always connected when parked in my garage. The device at the link is not a charger nor a maintainer. In fact, if you check the specifications, it says it will draw 1 ma. I have measured the parasitic draw on my 2021 C8 after it been off and undisturbed for 15 minutes or so.

Here is a description of the measurement process:
https://www.corvetteforum.com/forums...e-battery.html

The level I measured drops to 10-11ma and is consistent with what the service manual says about parasitic draw. So, this aftermarket device increases your parasitic draw by 10% - maybe that's negligible - but I would not put it on my car. Also, the idea of monitoring the battery from my phone (as long as I am 30 feet or closer) is not something I would value (but that is a personal decision, not advice). I also do not believe this device would have prevented most of the early battery failures reported on the forum. What would be of interest to me, as an experiment but not a permanent connection to the battery, would be a historical record of the parasitic current draw, especially during an OTA . But this device does not measure parasitic current draw.

If you did connect it, you will want to be aware that there is already an existing Battery Monitor Module in the car, that is electrically in series between the negative battery cable and the negative battery post. That Battery Monitor Module "monitors the system voltage, current, and internal temperature to verify they are within the normal operating range. It also monitors ROM or RAM memory faults, and performs other internal diagnostics." The information is use to detect faults and also to adjust the alternator charging rate. You would need to give some thought to where the aftermarket monitor should be connected with respect to the existing Battery Monitor Module. Since the aftermarket device draws some current, the negative lead should probably be connected to the negative cable side of the existing Battery Monitor, and not directly to the negative battery post. But I am not certain about that, and its another reason I would not use it on my car.

johnodrake

Hope your damage was light.

johnodrake

As CarlosVP said, some make a lot of short trips. This was the case with my wife's daily driver. I bought another CTEK for her car after the system kept giving her alerts to check 12V battery and the stop/start stopped working. Since using the CETEK the issues went away. Now all three cars are on maintainers.

CarlosVP

Thanks for the detailed explanation. My plan was to monitor the battery so I only connected the CTEK when necessary, but reading all the inputs, I'll refrain of buying this and connecting it to my C8. I guess I'll put the CTEK every once in a while.

Thanks a lot!

CarlosVP

Yes, I might do one short trip daily, but I go to work Tuesdays and Thursdays, so I think this should be enough to keep the battery at good levels

Avanti

I'm not sure what you are wanting to do. Perhaps just buy a cheapo, plug-in digital volt meter (ebay), assuming there is a plug-in easily available you can monitor.

BigF6B

Thank You johndrake for your concern...As powerful as this storm was in my area, I had some damage to a car-port that was added to the front of the garage by the previous owner of the home.I also lost my 8X10 resin shed in the backyard. All in all I consider myself very lucky this time around.

JerryU

FWIW, like my two C7’s myC8 is a DD but retired, now 22 years and that is not every day. As you note the alternator needs time to charge the battery. But worse with both the C7’s and C8. Like most new cars the battery is only charged to ~80% to save energy. It’s computer controlled and why you may see a step change in voltage.

Not at home so can’t post the discription of what controls to get to 80% but once there it lowers the alternator voltage to that required to just supply the current need, I.e. sound system, AC fans etc etc AND NO MORE. Lots of threads with some folks complaining about this new system. But my 2014 4 volume service manual had a table showing at 80% charge it will start a car after about a month! On 2 1/2 week vacation as I was often ~7 years with my C7s. Did not plug in my CTEK which I seldom use! Too many afternoon lightening storms and don’t want any issues with voltage spikes causing damage as have had with TVs, sprinter controllers (replaced- 3) etc. Never have had a dead battery.

At ~3 years I will start monitoring battery voltage about every month or 2 (after it has sat overnight to deplete any surface charge.). I will determine when to change the battery. But you can’t do anything to change how the charging system works so putting a monitor on might be helpful with a 3 year old battery but a volt meter works fine.

Here are the voltages I read. If the C8 has sat unused for say 3 days I see a voltage reading on the dash meter of ~14 volts on the 25 miles to town. That is suffient to be charging the battery. On the return trip it will drop to slightly over 13 volts. That is an indicator the battery is at ~80% charged. Expect when I get home from this trip it will take a few round trip ~50 mile round trips to get to 80%. Yep a 4 mile trip to the store might not be enough to make up for the starter motor energy used! In my case live 25 miles from town. Few things I reach in 4 or 5 miles!

Now as some I could use my CTEK all the time. PIA for a daily DD IMO. Yep that could keep it at closer to 100% and would get longer battery life. But a new battery every ~3 years is cheap compared to having to remove a charger every time I drive. Yep might get 5 years life but lead acid batteries will die!

Zymurgy

Install whole house surge protection in your service panel. I've had them on my 2 service panels for the past 20+ years and I've never even had to replace a light bulb (incandescent) in my house. The reduction in transient spikes is amazing. We have many thousands of lighting strikes in the area each year (I have a lightning detector).

JerryU

^^^
I should get the whole house protector. Currently paying the power company monthly for one to protect the two external heat pumps. But have had one electromagnetic burst that also erased my wife’s phone connection in the BMW! It was close to the house on a big pine tree! Apparently unusual but happened to a friends medical appliance business. With all of the wires in the ground for the sprinkler system apparently not easy to protect that controller, the surge protector I have it plugged into did nothing.

The battery maintainer I have the Street Rod plugged into 24/7 could be an issue. Low probability as would be with the C8. But the extra battery life not worth the inconvenience of removing charger as the C8 shuts down most power by ~10 minutes. Recall someone tested and parasitic current draw that was only ~15 milliamperes. It occationally returns power for like OnStar to gather tire pressure info but shuts it down quickly. That is a very low parasitic draw, much lower than most cars.

My Street Rod with no such system but electrical circuits are always energized for the digital dash (retains OD info) remote control doors and windows receiver)remote control for the sound system and CD player and is over 50 milliamperes - so needs a charger. It has provided very long battery life for the Yellow Top Optima AGM battery I use. If there was an electrical issue, I wired it myself and can do the same to repair. Hate to think about an issue with the C8!

Andybump

[QUOTE=JerryU;1605794548]The battery maintainer I have the Street Rod plugged into 24/7 could be an issue. Low probability as would be with the C8. But the extra battery life not worth the inconvenience of removing charger as the C8 shuts down most power by ~10 minutes. Recall someone tested and parasitic current draw that was only ~15 milliamperes. It occationally returns power for like OnStar to gather tire pressure info but shuts it down quickly. That is a very low parasitic draw, much lower than most cars./QUOTE]

Yep - I measured closer to 10ma actually. I'm wondering about your thought that a power surge might be an issue with a connected battery maintainer. I can see where the power surge could damage the maintainer. Were you thinking that power surge might make its way through the maintainer through the 12 volt lead to the car, and damage the car electronics? I never gave that a thought. I looked at the schematics, and they do still use transformers, so it would appear that if there was a surge in line voltage, there could be a surge in the output lead to the car as well. I never heard of anyone having that issue but I see the concern.

JerryU

^^^
Yep have had issues with powered items in my attached garage. For example the garage door opener on my wife’s SUV failed after a close lighting strike. Her phone connection in the SUV was lost but was told that both could have been due to an electromagnetic induced surge. I had to replace 3 sprinkler controls that are powered from the garage. But that could be caused by the many wires close to the ground going to the zone valves. Have had the TV HDMI fail,in a lighting storm but TV was fine. It is on a surge protector,

Yep a surge going though the CTEK is minor concern. But my main reason for not using the charger is with two C7’s and C8 have no battery issues leaving those cars for 3 weeks! Why bother using the charger. A 10 milliampere parasitic current draw is very low.

okaythen

Those battery monitor things do they actually work good? or they are BS gadget and doesn't really work? I was looking at this one before (How low of battery in the monitor then you have to put CTEK on right away?)

johnodrake

Depends on how long the trips are and how often you start the car.

mefly2

I like the CTek LEDs on the dongle ...