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Hi, I have some questions about winter storage / battery tender. I had a 2014 and 2015 C7 and I have a CTEK MUS 4.3 battery tender. In the past I have had no troubles whatsoever using the battery tender on these cars. I now have a 2017 Grand Sport Collector Edition. I plugged it into the outlet in the trunk last winter and in the spring when I went to take the car out of storage, the battery was dead as a post. This year, I plugged in the outlet adapter (red led flashed showing there was power at the outlet I assume), then I plugged the adapter into the battery tender cord then plugged in the tender / charger. The battery tender was then switched to the "snowflake" mode and immediately I saw the first few amber lights come on showing it was charging (car had not been driven for a couple of weeks). After a few hours, I went out to check and the led's had all turned off except a green flashing light. I contacted CTEK to make sure I was doing things correctly and the technician told me that the green flashing light indicated that the battery tender was searching for a battery?? To me this means that the outlet "shut off" after a short time. I thought this outlet was powered all of the time and my manual says to use it to plug in the tender? Obviously, the battery will be dead again in the spring if this is any indication. So...what are everyone's thoughts? Should I lift the floor mat and connect directly to the battery using the alligator clip leads or ??? Thanks!
My tender has a slow flashing green light when it has brought the battery up to full charge and is "maintaining" it. No other lights are on, just the slow flashing green light.
Thanks guys for the replies. I also have a slow flashing green light - The technician at CTEK told me this indicates the charger is disconnected and "searching" for a battery. When I popped the trunk and wiggled the plug, the light goes off and 4 amber lights lit up showing a charge in process. Yes I am using the trunk plug and I also wiggled the plug to get the charger to change. now....I am not sure if popping the trunk changed the status on the charger or wiggling the plug, I did not wait after opening the trunk to see if it changed. I was wondering if the circuitry is cut off once the trunk has closed similar to the way the dash, lights etc. turn off after a short time to save the battery? It may be that the trunk needs to be left ajar?? I asked the technician about connecting directly to the battery using the alligator clips and I'm waiting for his reply via email. Will keep you posted.
AZCANUK - pop your trunk and wait a few minutes before trying to wiggle the plug. Let me know if the charger status changes at all. If not try wiggling your plug and see if it makes a difference? Be interesting to see if it changes. Thanks.
Hi Guys, I just received the following from the CTEK technician. I attached a photo of what my charger looks like right now and he replied based on that photo.
"Hi Dan,
Right now your picture indicates that charger is in absorption (step 4) so everything is working as it should . Ultimately, the charger will reach step 7 (float maintenance) and 10 days later, step 8 (pulse maintenance) which is where it will remain until removing it from your battery. Eventually all 8 lamps will be lit which is what you want to see. A flashing power lamp is never a good thing to see if your plan is to charge and maintain your battery. If the socket does lose power eventually going directly to the battery with clamps or eyelets is recommended if you can reach it. You can leave it on snowflake the entire time and there is no need to restart the charger while it’s maintaining."
Last edited by Tweedy; Nov 19, 2019 at 03:30 PM.
Reason: Clarification
I bought maintainer and it didn't have the cigg lighter adapter so I ordered one from Amazon and plugged it in and put my cover on. The next morning I thought I would go and check and make sure all was ok and guess what the maintainer indicated not charging so I took off the cover and the adapter had fallen out. So I put the clothespin clip connectors on the battery and have no problem now.
I left the trunk ajar now for the past 2-3 hours and the battery tender is woking like a charm which confirms that when the trunk is closed tight, it somehow shuts off the outlet after 10 minutes or so. I put the cover back on with the trunk slightly open and will check periodically but it looks good so far!
I have found the cigarette lighter adapter to be a wee bit flaky. I always press it all the way in with a twist. I do shut the trunk fully with no issues. I use the exact same CTEK as OP (I checked.) The last two lights should be GREEN, not amber, and it takes a few days for the last one (Pulse) to turn green.
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I have the GM accessory Battery Tender and I always keep the trunk popped. Interesting to hear that your outlet loses power after a short time with the trunk closed.
I left the trunk ajar now for the past 2-3 hours and the battery tender is woking like a charm which confirms that when the trunk is closed tight, it somehow shuts off the outlet after 10 minutes or so. I put the cover back on with the trunk slightly open and will check periodically but it looks good so far!
The trunk outlet is the only thing that stays on after 10 minutes...It does not shut off.
The trunk receptacle is not as good as it could be and closing the trunk could be enough to make the plug loosen.
See page 249 in the 17 owners manual. It looks like you have a 17 GS collector edition.
The trunk outlet is the only thing that stays on after 10 minutes...It does not shut off.
The trunk receptacle is not as good as it could be and closing the trunk could be enough to make the plug loosen.
See page 249 in the 17 owners manual. It looks like you have a 17 GS collector edition.
Well.... I had the trunk closed and I got the error green flashing led on the battery tender. I opened the trunk and tried the charger again and it works like a charm. The charger has cycled all the way through now to the 7th cycle with a green light and the CTEK technician told me it can take up to ten days before it turns on the last green light and goes into pulse mode. For giggles, I disconnected the charger and put a voltmeter on the outlet in the trunk. I then closed the trunk all the way. The outlet loses power after 10 minutes. So...I have to keep my trunk open. I called my service department and they said to leave the trunk ajar as well. Not sure why / how it works, but with the trunk open my charger works as designed so I put the cover back on the car and will leave the trunk slightly open for the winter.
PS - Just looked at the manual and that's exactly how I have the setup but notice in the picture that the trunk is open? It works with the trunk open so that's how I going to proceed.
I think it would be best to hook the clips directly to the battery for long term storage.
I have the Corvette maintainer hooked up at the plug in the trunk and have to wiggle it around to maintain contact once in awhile.
I leave the trunk open and check it as I walk by once a day.
I'm trusting the plug in and cannot check it daily as the car is 1300 miles away in Montana for 6 months. It worked fine all last winter so I just have to hope. I do have someone check on it once a week tho. I have thought about going straight to the battery with a beefier tender but most say stick with the plug and play.
I have the GM accessory Battery Tender and I always keep the trunk popped. Interesting to hear that your outlet loses power after a short time with the trunk closed.
I thought if I left the trunk popped it would keep the interior lights on or possibly create some drain on the battery. Apparently not.
Tweedy,,,was your car originally sold by Jenner in Victoria?
Hi, No, I bought it through Northstar GM in Cranbrook / Creston but I found the car in Sherbrooke, Quebec at Thibeault GM and had the BC dealership "import" the car from them.
Battery tender help!
