School me on Battery tenders
 

So now my car is only driven on track it will sit in my driveway for periods with out drives. I will start it and let it warm up one week for 15-20 mins.

Will battery tenders keep the voltage full on the battery or will they only kick in when the battery drops below X volts. I have a small 6lb AGM style battery so it does not have alot of juice. I don't want it to die but I want to understand how this will work.

Battery tenders have a 'float' mode, where they will first charge the battery up to full and then "pulse" charge it - it lets the voltage decay for a bit, before then charging it back up. This can vary in time, from milliseconds to minutes.

As I understand it, with modern chargers/tenders it's literally as simple as hooking it up and forgetting about it. The battery will stay charged for the length of its normal life.

I've had two CTEK models, and the second one doesn't even have an 'AGM' option on the car/motorcycle select button anymore, as it auto-detects whether the battery is lead-acid, calcium, or AGM. Cannot be used on lithium tho iirc.

Get any modern maintainer around 1 to 1.5 amps and you will be fine in California. Keep plugged in at all times with a tiny battery.

My .95 and 1.5 tenders have AGM settings. They are Duracell.

Use this for a truck I only drive every 2-3 weeks, have the clamps run straight to the battery and haven't had an issue in almost a year since I added it. Can't speak to what kind of voltage it's actually putting out but wouldn't imagine it's adding enough juice to be a problem and doesn't need to be plugged in so no cords all over the place.

https://www.amazon.com/gp/product/B0...e?ie=UTF8&th=1

An option that is rarely discussed is solar.
If the car is outside then it is a very efficient system.
I use one on the boat and it has never let me down.
https://www.amazon.ca/Maintainer-Wat...555637262&th=1

This looks like a bot response!

Reported! :lol:

Go to your battery specifications. It will tell you max charge voltage and recommended float voltage. Then find a charger that falls into those specifications. It is best to get a charger that has temperature compensation. I have always had good luck with Battery Minders. They cost more but also help reduce battery sufidation.

I've had my motorcycle batteries (similar size) on chargers since '05.
AGM have been fine with Battery Tender units.
You can buy extra SAE pigtails to attach to any 12v battery in your fleet to plug the tender into.
I put one on my 86 and needed it once when the keyfob opened the trunk overnight when I wasn't looking.

If you go with Lithium batteries the chargers need some extra computery stuff in the box but those work too.

Good bot

Is there an article somewhere about how they affect the battery? I am interested in research as usual with graphs and bars. Whenever I think of something, I have to do it. Now I got interested in batteries when I came across this topic. I did not even think before how it all works and what the differences are.

Rabbit hole activate!

https://batteryuniversity.com/articles

Thanks for the inputs!

Sent from my Pixel 6 using Tapatalk

calcification of the plates does tend to happen as part of any constant charging cycle. many battery maintainers tend to try to abate it a little by introducing an a/c waveform into the charging cycle to 'jiggle' the deposits loose from the plates.


my experience is that intelligent battery chargers with a 'battery recovery' mode will do a better job at it anyways.

*went 7 years on the oem battery alternating between the maintainer for extended parked periods and 2 recovery cycles on the charger near the end of the 7 years.

I had an odyssey AGM battery that was super picky about charging voltage and specified a minimum voltage too.. otherwise it would sulfate and somehow void your warranty.

I only found 2 or 3 chargers that would hit their spec.. besides the ones Odyssey themselves manufacture. Ended up just getting their charger randomly on supersale at amazon anyways.

I recommend installing a ring terminal fused SAE connector for easily connecting your chargers. This is preferable to leaving alligator clips attached to your race car. My charge connectors poke out of the hood cowl. https://m.media-amazon.com/images/I/...AC_SL1500_.jpg

And I also use a 25 foot SAE extension cable. This allows me to run my cables outdoors without having my chargers exposed. Since the connections are fused, I have less to worry about with short-circuiting. https://www.batterymart.com/merchant...081-0148_2.jpg

The "Battery Tender" brand waterproof chargers are the best for long-term maintaining. They are waterproof, and mine has lasted 20 years outdoors. They charge at about 10 watts, and maintain your battery at a float charge.

https://i.ebayimg.com/images/g/fAUAA...wzi/s-l640.jpg


The chinese branded battery chargers are pretty great to own too. I have a Foxsur charger that can do both 12v and 24v charging, at 6 amp. Or 60-70 watts on a 12v battery. I plug my car up to this charger 30 min before starting the car every day, and it definitely puts some juice into the battery - I figure this helps somewhat so I do it routinely.

https://m.media-amazon.com/images/I/...AC_SL1500_.jpg


Another thing to note is avoid old "heavy duty" battery chargers like the kind grandpa had in his garage he bought from Sears 35 years ago. Example is the one my grandad had, that when I plugged in it boiled my car battery at 15.5 volts.
https://i.imgur.com/w10bFKF.jpeg
These older chargers have poor voltage regulation. and will boil your battery at 15+ volts and can hurt electronics. It almost fried my truck's electronics before I started looking into it and running a voltmeter on it. Having a good voltmeter is a handy tool for checking battery health.

The only problem I'm personally seen with a battery maintainer, was one hooked up to a pair of AGM's for an RV. the maintainer was undersized and couldn't push the batteries hard enough to switch over to the float/maintain cycle. Just cooked them after a couple months.

Shouldn't be an issue with a single small AGM.