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I've used Battery Tender's on my motorcycle's for years, and still do. Having said that, I'm not a huge fan. Yeah, I suppose a tender is helpful to a degree, especially if the bike or car sits for extended periods.
What I don't like is the "green light" that gives a false sense of security that the battery is fine when it actually isn't. The light only indicates that voltage is normal, but the cranking amperage may not be sufficient to start the bike or car. I also have not found the tender to increase the life of the battery.
Never used one. I just turn the battery off with a blade style disconnect switch all the time.
Current Walmart battery is 7 years and 5 months old and never a problem with it.
Time for a new one just to be on the safe side.
I do the same thing. I leave one 1980 Corvette for seven months, with the battery disconnected and it starts right up. Just to see how much it discharged, I hook up a 10 amp charger, and within 1/2 hour it is fully charged.
I purchased a Napa Battery in early 2012 and replaced it this Spring, just because it was seven years old, but it still started the car after sitting for 7 months.
I am leery about leaving the battery connected in an older car even for a few days, because of the risk of fire.
Last edited by mark79,80; Sep 11, 2019 at 09:19 PM.
I try to keep my cars on a battery tender when not in use. I started using the timer on mine.
My battery tender has the 2 lights with 3 modes
1- less than 80%
2- greater than 80 less than full
3- fully charged, in maintain mode.
I found if I was driving the car and plugged it in, it took less than 20 min to show in maintain mode. If cars were sitting for a bit, still around 2 hours they were full. So so I set my timer for 3 hours every night.
I do do notice that if you c3 has a working clock it will drain the battery. I forgot to plug mine in once and after 3 weeks I could tell the battery was not 100% when the car turned over
From: Loud, Raw and Dangerous 1968 327 4S in Southern California
I don't use one either. New battery and alternator...car will start after a month no problem. I check it with a cigarette lighter plug-in LCD voltmeter. Starts out at 12.7 volts and only drops to 12.0 volts after a month. No aftermarket parts installed that draw any significant current, just a modern stereo. If it is going to be stored for a longer time and/or I am out of town I use a battery disconnect switch for safety.
I don't use one either. New battery and alternator...car will start after a month no problem. I check it with a cigarette lighter plug-in LCD voltmeter. Starts out at 12.7 volts and only drops to 12.0 volts after a month. No aftermarket parts installed that draw any significant current, just a modern stereo. If it is going to be stored for a longer time and/or I am out of town I use a battery disconnect switch for safety.
Redvette2
you realize according to most charts that dropping from 12.7 to 12.0 is 50% discharged?
From: Loud, Raw and Dangerous 1968 327 4S in Southern California
Originally Posted by Tiger Joe
you realize according to most charts that dropping from 12.7 to 12.0 is 50% discharged?
Fortunately at 12.0 volts it can still start my car. Set the choke and it fires right up. As the battery ages it might become a problem but I have a 10A battery charger in the garage if I ever need it. As mentioned anything long term then the battery gets disconnected. My 2011 Jeep battery lasted 8 years/100K miles before it failed and it discharged much faster than the Corvette. I guess the main reason I don't like trickle chargers is the connect and disconnecting of the cable and plug every time I want to go for a ride.
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2024 C3 of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
Originally Posted by jim2527
Nice video on long term storage....
Amazing video. I can't imagine how much it would cost to leave a car there! And, it's almost impossible to find any parking in London, let alone underground, so how has that chap managed it, without shelling out a few million?!
Some intersting info though.
And yes, I keep our '78 on a trickle charger all the time its here in the garage.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
I have a battery tender which has the detachable leads. It came iwth clamps and direct bolt on leads that I have atteched directly to the battery. I drive mine atleast 2 times a week from may until october so I dont worry about it. I also have a battery disconnect hard mounted between the seats so I turn off the main system everyday. I have bypassed thhat for the clock and the radio so they never lose time or memory. During the winter is when I do the most work on it so if I'm cranking the motor or doing brief starts I will throw on the smart charger and let it sit until the green indicator comes on indicating a full charge. Itry to keep it ready to go at all times so if the urge hits I can crank her and go.
I keep all of my cars on maintainers when they aren't being driven. If I know I will drive a car within a few days after I have driven it then I may not hook it up, anything longer it goes on the maintainer. I don't know if they extend battery life, I'm at 8 years on the oldest battery, but no matter how long they sit I've never had any issue with starting or otherwise.
Last edited by buckybadger45; Sep 14, 2019 at 12:34 PM.
I’ve used Battery Tenders on my cars, boats and motorcycles for close to 50 years.
Their products have never failed me.
Through the past 50 years I’ve only just recently purchased my third Battery Tender unit.
I still have the second one I purchased, it still works and I only replaced it do to it’s age.
[QUOTE=Stephen Irons;1600151324 And, it's almost impossible to find any parking in London[/QUOTE]
We were in London last May, I was surprised how many high end cars were parked street side. All covered in pollen, dirt and other grime. The owner of the boutique hotel we stayed at parked his Bentley out front.
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2024 C3 of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
Originally Posted by jim2527
We were in London last May, I was surprised how many high end cars were parked street side. All covered in pollen, dirt and other grime. The owner of the boutique hotel we stayed at parked his Bentley out front.
We have a very cool NEW Product that is really beneficial for eliminating those dead battery situations, and also at allowing you to really see what your battery is doing. The product called the Battery Tracker. Its a small Bluetooth device that attaches to your Car's Battery in a two minutes, and then sends all your voltage and battery performance data to your Phone and the Battery Tracker App we developed. So it a massive help in eliminating dead batteries but does much more than that. The Battery Tracker can be seen HERE... https://shop.antigravitybatteries.co...ker-lead-acid/ It does these things...
1- You can see your past 5 minutes Real-Time voltage on your phone without ever needing a Multi-meter, or needing to access your battery, or look at your Cars Instrument Cluster. You can even do this from OUTSIDE your Garage and being up to 30 ft away from the Car. For example, if you are within 30 ft of the car you can check your voltage and get all historical data on your phone and know the status of your battery. Or if you are with the car you can do some testing by turning on the Stereo or other electronic and see the effect on the real time voltage screen.
2- It also saves 31 days of historical voltage in an easy to read graphic page... For example this means you will see every start attempt, every driving event (since your voltage goes up when driving/charging), you will see how long you drove for, you will see how fast your voltage goes down while the car is in storage or sitting for a few days and know how long your car can sit before over-discharging the battery. You could see if a new accessory is drawing down the battery faster because the graph timeline for each day will show the amount of discharge.
3-You will get warnings sent to your phone if the battery voltage is going too low. You can set at what voltage you want the warning sent to your phone.
4- Last it offers a Cranking Test and Charging Test to inform you if you voltage is going low on Cranking or if you Charging System is not charging. So it takes all the tedious tasks of checking and tracking voltage and makes it so simple that you don't even have to watch your battery... just look at the App on your phone and have all the data there.
Below are some screenshots then a video. ON this screen shot is the Main screen showing 5 minutes of real-time voltage. I had the Car running... then turned it off and you can see the voltage settling back down... no need for a Multi-meter, the graphic is on your phone and seeing the live voltage changes.
ON this screen shot below it is the Historical Data. I can see that Car Battery was sitting at 13.2v all day then I started it and went for a drive around 2:30pm... I stopped for a short time around 3:15pm, you can see this because the voltage went down.. and then I started the car and drove again... then stopped the car at about 4pm and did not drive it again. You can see the voltage is now in a higher state of charge after my drive. When you slide your finger on the screen a RED LINE appears and shows the exact voltage, and time of day. So you can see the accurate voltage at any time over 31 days. So it very comprehensive and beneficial information if you are interested in this type of Data, and it make it all very easy to see what your car is actually doing.
GTR1999,
That brings up a good point about surges / spikes. I too fried Battery Tender during a thunderstorm.
I have my two garage door openers plug into a pair of single outlet surge protectors, because of the same reason. I believe they came from Amazon and have a green light showing its working. I should look into another surge protector for the charger.
O.P.
No matter which tender you buy, make sure it has some type of indicator lights. Its worthless if you don't know what the unit is doing.
In areas prone to lightning, it is a good idea to use a surge protector. Most of these (especially cheap ones) have little ot no surge protection.
After reading all the comments (and watching the Supercar Garage video Jim2527 posted in comment #31) I decided to take it up a notch and bought the CTEK Multi US 7002 battery charger.
Quick question. CTEK instructions call for the negative charger cable with the alligator clip to be connected to a metal ground and not directly to the negative terminal on the battery. Since the battery in the 1970 coupe is in the compartment behind the drivers seat and there is no engine metal ground, would you guys just connect directly to the battery? As CTEK also provides eyelet cables to be connected directly to the positive and negative battery terminals, why should there would be a problem using the alligator clip cables directly on the battery? (I will likely ultimately use the eyelet cables, but would like to test out the charger first.)
