Battery Tenders, how long can they stay on?

[Vette40th]

This is a beat to death topic, I understand. But, I have to put my Vette, C4 on a tender as I am going away for a long time. I used old Schumacher from Wal Mart years ago, and I don think they worked well. Still had issues after the fact.
So, I bought a Noco Genius 2, and the battery was fully charged, and I put this on.
What length of time is reasonable to expect this to keep battery alive? Its a 2 year old batter now, but was at 12.7 after using my Sears charger over night.

[Big bob]

I believe that is a charger not a tender.

My bad you made me look it appears to be both. I have seen others left on for years and the battery dried up.

[Vette40th]

Originally Posted by Big bob

I believe that is a charger not a tender.

It says after the charge, and light is green it will go into a maintenance program and can be left indefinitely.
Thats why I ask, citex (sp), battery tender (jr?).. Different terminology is what my issue is..

[Big bob]

After reading I think your good.

[Murray]

If it’s a battery tender you can leave it indefinitely. Mine goes on in the fall and I don’t look at it till late March/early April.

[snide]

Or you could just disconnect the battery.

For how long will you be in prison?

[JRD77VET]

I have Battery Tender Jr's for both my Cub Cadets. I unplug them to use them and plug them back in when done.

My little 340 CCA batteries now last many years.

[Vette40th]

Originally Posted by snide

Or you could just disconnect the battery.

For how long will you be in prison?

6 to 12 weeks, gen pop..

[Bruze]

Originally Posted by Murray

If it’s a battery tender you can leave it indefinitely. Mine goes on in the fall and I don’t look at it till late March/early April.

Same here. That's what they're designed for.

And to the OP: A voltage check doesn't tell you the health of the battery, it only tells you the available voltage. It might be 12+, but not enough depth (volume of current) to even crank an engine one spin.

To test the health of a battery you need a hydrometer (cheap, any auto store) or a load tester.

[Big bob]

I have a noco 10 and never knew this thank you.

[CurtP]

I have a CTEK 7002 that's been on the Porsche since December 2017.

[Vette40th]

Originally Posted by CurtP

I have a CTEK 7002 that's been on the Porsche since December 2017.

So is that why Porsches never break, because they are stored forever?
J/K I would love a 911, damn would I.

[04 commemorative]

I left mine on all the time,removing it took maybe 3 seconds if I wanted to use vette,then plugged it back on.

[Yadkin]

Read the factory manual. It has useful information, mostly written by the guy who designed the thing.

I lost my tender in the move. That I could leave on indefinitely. I plug my battery charger in the 'Bird at 2 amps overnight about every 2-3 weeks.

[Bruze]

Originally Posted by CurtP

I have a CTEK 7002 that's been on the Porsche since December 2017.

I had a Tender Jr. on my boat battery from 2011 until I sold the boat in 2021. Battery was still usable.

I keep a 20+ year-old Jr. on my Vette during the winter, and an old Schumacher on my '51 Fergie 6-volt system all the time unless I'm using it, which is rare.

Seldom-used batteries with a tender will last way, way longer than a seldom-used one with no tender.

[Jughead]

I have my C6 in storage most of the year as I don't have a 6 car garage. Been using the same C-tec charger FT.

[Vette40th]

Originally Posted by Yadkin

Read the factory manual. It has useful information, mostly written by the guy who designed the thing.

I lost my tender in the move. That I could leave on indefinitely. I plug my battery charger in the 'Bird at 2 amps overnight about every 2-3 weeks.

I had to download the manual. I did read it. The manual in the package was font 1.
But, I was being a little OCD to verify. Tenders have many functions stated, algorithms for charging, maintaining, frequency systems to agitate battery, etc etc.
Its like phone chargers, some phones/laptops(with flexi charge bios) will shut the charging off at certain levels. Its good to know the safety and features.

[Frankie the Fink]

I leave tenders on my boat and jet ski for months at a time....no issues....make sure they're on a surge suppressor if you're going to be away for an extended period.

[Norm]

Have several Deltran Battery Tender Plus units, use on the lawn equipmen batteries for winter layup works well.
Used one on my son's C4 when he was in the sandbox for a year, fired right up. Have one on the C3 now since Oct, will stay on untiil Mar/Apr.

[Mick]

Originally Posted by 04 commemorative

I left mine on all the time,removing it took maybe 3 seconds if I wanted to use vette,then plugged it back on.

That's pretty much what I do. If we are having a run of nice weather such that I'm pretty sure I'll have the car out multiple times in a week, I don't bother connecting it. If I think it will be more than a day or two before I drive it again, I'll connect it.