School me on Battery tenders - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

jflogerzi · 08-29-2022, 10:23 PM

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.

euniqe · 08-29-2022, 11:17 PM

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.

Sapphireho · 08-29-2022, 11:32 PM

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.

ThatYeti · 08-30-2022, 07:06 AM

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

Tcoat · 08-30-2022, 07:24 AM

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!

Ohio Enthusiast · 08-30-2022, 07:59 AM

Quote:

Originally Posted by Tcoat

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

Reported!

Grady · 08-30-2022, 08:34 AM

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.

bcj · 08-30-2022, 12:27 PM

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.

RToyo86 · 08-30-2022, 12:33 PM

Quote:

Originally Posted by Tcoat

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!

Good bot

Gialren · 08-30-2022, 05:01 PM

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.

Grady · 08-30-2022, 05:56 PM

Quote:

Originally Posted by Gialren

Is there an article somewhere about how they affect the battery? I am interested in research as usual with graphs and bars.

Rabbit hole activate!

https://batteryuniversity.com/articles

jflogerzi · 08-30-2022, 09:57 PM

Thanks for the inputs!

Sent from my Pixel 6 using Tapatalk

soundman98 · 08-30-2022, 11:41 PM

Quote:

Originally Posted by Gialren

Is there an article somewhere about how they affect the battery? I am interested in research as usual with graphs and bars.

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.

Tcoat · 08-31-2022, 07:24 AM

Quote:

Originally Posted by RToyo86

Good bot

08-30-2022, 07:24 AM	#5
Tcoat Senior Member Join Date: Jul 2014 Drives: 2020 Hakone Location: London, Ont Posts: 69,845 Thanks: 61,656 Thanked 108,286 Times in 46,456 Posts Mentioned: 2495 Post(s) Tagged: 50 Thread(s)	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! __________________ Racecar spelled backwards is Racecar, because Racecar.

08-30-2022, 05:01 PM	#10
Gialren Junior Member Join Date: Aug 2022 Drives: ft 86 Location: San Luis Obispo, California Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	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. Last edited by Gialren; 09-30-2022 at 06:24 AM.

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08-29-2022, 11:17 PM	#2
euniqe Member Join Date: Oct 2018 Drives: 2012 Toyota 86 GT Location: Australia Posts: 17 Thanks: 7 Thanked 20 Times in 10 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	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.

08-29-2022, 11:32 PM	#3
Sapphireho ¯\_(ツ)_/¯ Join Date: Mar 2016 Drives: '15 ultramarine Location: Idaho Posts: 13,234 Thanks: 5,462 Thanked 18,289 Times in 8,638 Posts Mentioned: 156 Post(s) Tagged: 0 Thread(s)	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.

08-30-2022, 07:06 AM	#4
ThatYeti Senior Member Join Date: Aug 2019 Drives: BRZ Location: Connecticut Posts: 195 Thanks: 45 Thanked 25 Times in 23 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	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

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