Battery Tender recommendation

[silverf0x]

Been a while since I've posted. I still don't use my 2015 S4 that much (still has 19k miles), and even less and less these days (obviously). I did prep my car for winter but I don't think I'll use it afterall (beater does the job). Since I cannot store it inside at warm temp it'll be outside in the cold all winter (under a carport so no snow on it) and I was looking for a battery tender recommendation. I used to have a CTEK 93-56-864 MUS but I lost it so I'm looking for a replacement.

Important note: last year I had to change the battery on the count of the car not being used enough so it died and I figured I would not install an AMG battery since I would have to change it every 2 years anyway so I have a standard battery.

While price is not a problem, I'm looking for a tender that can be plugged in normal outdoor 120v outlets and can sustain -30c
I still have CTEK's accessories that allow to charge via the cigarette lighter plug but I won't use it since the car needs to be turned ON for this accessory to work (go figure!).

[sacandagaD]

I've used a couple of versions of the actual "Battery Tender" brand with good luck in the past. Not sure about at a sustained -30C, so YMMV.

[DarrenOman]

Why not disconnect the battery if the car is sitting unused.

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[KMPRSSD]

I have use this on my garaged S4 (I'm in the same position as you under 20k miles and less and less use).
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I also use this at my job to keep our tow motor charged. It is in an unheated car port but in very cold northeast temps. I have had very good luck with it.

[PenttisHSR]

I still have CTEK's accessories that allow to charge via the cigarette lighter plug but I won't use it since the car needs to be turned ON for this accessory to work (go figure!).

It's actually very simple to make the cigarette lighter socket permanent live by looping a live feed to it's fuse. I used this guide over four years ago and has worked perfectly for me since.
Link......... https://www.audizine.com/forum/showt...it-s-always-on

[silverf0x]

Why not disconnect the battery if the car is sitting unused.

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Because I would like to still be able to use the car quickly if I need it for an urgent matter. Plus wouldn't the battery suffer even more from being on a shelf?

- - - Updated - - -

I have use this on my garaged S4 (I'm in the same position as you under 20k miles and less and less use).
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I also use this at my job to keep our tow motor charged. It is in an unheated car port but in very cold northeast temps. I have had very good luck with it.

Thanks I will purchase that unit, it seems to fit my needs!

[silverf0x]

Last question, is it better to install the tender directly on the battery in the trunk or in front is ok too?

[KMPRSSD]

Last question, is it better to install the tender directly on the battery in the trunk or in front is ok too?

This has been a topic for debate. I go right in the trunk cause I have nothing in there and it’s not that difficult to put back the tool kit. I put the car cover in there anyway, so I have to open it regardless. Some have said the posts in the engine bay aren’t ideal because they add more resistance to the loop. There hasn’t been much data I have seen to back that up. I may start doing the hood myself, just cause it is that much easier.


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[1bsingh]

Audizine members are too clutch. In the same boat as OP. Thank you


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[grovlet]

I have this one setup in my garage on my Camaro:
Battery Tender

Recommended for a few reasons:
- Weatherproof - Doesn't mention actual temps - but I have NO insulation & only rough framed windows in my garage in New England and had ZERO Issues
- It is designed to maintain the battery - so reduces charge level as battery is charged to avoid overheating and includes auto monitoring
- Can be left plugged in constantly with no oversight - 120V standard electrical plug
- Comes with a set of "Quick Disconnect" pigtails - one has "O" rings that can can be hard wired directly to the battery and the other is set of clamps used for easy charge connections as normally expected

Sits connected 100% of the time (Quick connected with underhood direct mount to battery ) It's saved me form replacing battery what was every 2 years (up to 6 years now) - and I can disconnect it in under 30 seconds to drive the car with the quick connection.

Well Worth it....

[S4'ed]

There is no difference connecting the battery tender in the engine compartment versus the trunk. The resistance of the wiring (from the battery to the front) makes no difference to the small output current of the tender. The wires from the battery to the front have a low enough resistance to carry the engine starting current (300 to 600 Amps), as compared to the tender charge current of 2 Amps or less.

I recommend that any tender be plugged into a quality surge suppressor, like the Tripp Lite Isobar 2:
https://www.amazon.com/Tripp-Lite-Pr...s%2C169&sr=8-4

I like the Deltran "Battery Tender" brand of products. (Amazon, Costco, Walmart...)

Concerning taking the battery out of the car, the battery does not suffer any more self-discharge if you take it out of the car, "putting on a shelf", versus just disconnecting one terminal.

[silverf0x]

There is no difference connecting the battery tender in the engine compartment versus the trunk. The resistance of the wiring (from the battery to the front) makes no difference to the small output current of the tender. The wires from the battery to the front have a low enough resistance to carry the engine starting current (300 to 600 Amps), as compared to the tender charge current of 2 Amps or less.

I recommend that any tender be plugged into a quality surge suppressor, like the Tripp Lite Isobar 2:
https://www.amazon.com/Tripp-Lite-Pr...s%2C169&sr=8-4

I like the Deltran "Battery Tender" brand of products. (Amazon, Costco, Walmart...)

Concerning taking the battery out of the car, the battery does not suffer any more self-discharge if you take it out of the car, "putting on a shelf", versus just disconnecting one terminal.

Thanks for all the advice. As you seem to be very knowledgeable on this topic, may I ask which model of Batter Tender you would recommend? I'm looking for something that can sustain low external temperature, can be easily tucked under the hood and easy to remove
I could also consider a permanantly installed module to use even in summer (since I dont use the car that much).

Would something like this work? https://www.amazon.ca/Battery-Tender...731139&sr=8-21

Of course I would combine it with this as per suggested: https://www.amazon.ca/gp/product/B00...K6Y9EEQB&psc=1

[S4'ed]

The one you picked is a 24V unit, can't use that for your 12V car.

Get this one:
https://www.walmart.com/ip/Battery-T...rger/420435088
This would be fine. Unless it is directly exposed to rain/water, these cheaper models are good. No need for it to be rated for more than an amp or so of output current.