Trickle charger questions

[Dohn]

I've put the coupe away for the winter and have two questions.
1) If I don't plan to use the car until March at the soonest, is it better to leave a trickle charger on it the whole time, or wait until February or so to attach it?
2) My battery is under the back seat, but there is a modern-style remote positive lug under the hood. Is it ok to use the remote lug and a good negative connection for the trickle, or should I connect the charger directly to the battery?
Thanks and Merry Christmas to all...

 

[jmackro]

#1 The answer would depend on the type of device that you are using. An old fashioned "charger" should not be connected for an extended period. The things called "battery tenders" are intended for long term use. The makers of premium "tenders" claim theirs are kinder to your battery than the cheaper varieties - dunno how true that is.

#2 The positive lug accessible under the hood will work just fine.

 

[Dohn]

It's a BMW branded trickle charger, aka battery tender. I used it on my 335i one winter and the battery went dead anyway, but I think the battery was just due for replacement. Those modern cars draw a lot of amps just parked.

 

[steve in reno]

I have used a Battery Tender brand for 10 years. i use it on the e9, motorcycle, and trlr batteries. And now my diesel truck.
It has leads that stay connected to the battery posts with a quick connect. Or big clips to battery.
Easy hook up and has lights to tell you what it it doing.
$25 on amazon
I have one that it needs to be replaced. They work very good.
Your batteries will last much longer since they will be kept charged.

 

[dpdapper]

#1 The answer would depend on the type of device that you are using. An old fashioned "charger" should not be connected for an extended period. The things called "battery tenders" are intended for long term use. The makers of premium "tenders" claim theirs are kinder to your battery than the cheaper varieties - dunno how true that is.

Any thoughts on just disconnecting the battery via a quick disconnect for a couple of months vs. keeping it on a battery tender? Unlike a modern car with lots of electronics, disconnecting the battery on an e9 only stops the clock!


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[mulberryworks]

Lead acid batteries will self discharge 5% per month just sitting disconnected. Warm temperatures will increase that rate and batteries with lots of cycles on them will also have a higher rate. There are a number of cheap battery tenders out there, but I'd be tempted to get a better one that tells you what it's doing. Any rechargeable battery doesn't like sitting discharged for extended periods. It will damage it.

 

[Honolulu]

I wonder if current (no pun intended) batteries self discharge as fast as they used to. Old batteries had cases that were slightly porous, less ding to an acid path to ground. I read that newer batteries with impervious plastic cases don't (as much?) behave that way.

 

[Philippe db]

Hi Guys,

Used a trickle charger for years but in the end the battery will still give up. Now for the first time I leave the batteries in the cars but disconnect them. Curious to see what they will do after 5 months.

To be on the safe side I bought this jump starter to assist when necessary.

https://www.ravpower.com/14000mah-portable-charger-car-jump-starter.html

 

[Nicad]

I'd think the battery would rather be on a tender over the winter months than not. I've had a battery on a Yuasa Hot Shot for .years and years. (guessing 6) Started up my dormant Corvair in cold weather with a long bout of cranking this month.

 

[Gary Knox]

I've used the very inexpensive battery tender/maintainer from Harbor Freight (on sale with a coupon for between $5 and 10) on typical lead acid batteries in cars I've stored over the winter for at least 10 years. It always maintained the batteries, and they were good for that period of time. I usually put the maintainer on for a few days, then remove for about a week, then recycle that procedure all throughout the storage period.

I use the sophisticated CTek maintainers on my Absorptive Glass Mat batteries, as they seem to need more precision in the 'tending' process. Only have about 3 years experience with them. Have had no issues with the 'service' battery (not used for starting the engine) on the MB SL55 AMG I've had for 3 years, keeping the CTek tender connected any time I'm not using the car for over a week. These batteries on these cars tend to discharge in ~3 weeks if not maintained. I use the same 'on and off' procedure with the CTek as well.

 

[Bwana]

I've got a number of vehicles, including motorcycles, in two locations and so have a lot of experience with batteries and tenders. I had a battery on a 1996 Triumph Trophy boil dry using a Beltran Battery Tender on constant float. So the way I hook stuff up now is with a $5 timer from Lowes (the kind with the big dial and the clips you push in) plugged into the Beltran and set for one hour. I've never had a battery go flat with this setup and have batteries sit for more than a year and the vehicles fires right up.

 

[glenn in encinitas]

I have used the BMW trickle charger with the cigarette lighter plug for over 15 years and it has never let me down. Battery life is substantially longer (8 years and running) than my vehicles that do not get the trickle charger. It’s super easy to set up- just plug it in!

 

[Belgiumbarry]

i think Bwana has it right... i hook up CTek from time to time. Not continously.

 

[JFENG]

My Costco
Has the 3 amp Battery Tender for $29. The 3a means it charges faster if the battery is a bit low. Plus it does gel and AGM types. That’s less than half of what I’ve seen it for at the auto parts store. I have three and picked up a fourth.

Only downside is size. I’ve had CTEK’s and they’ve gone bad on me. Never happened with a Battey Tender brand charger.

 

[RMP]

I'm with Glenn, 15 years w/BMW trickle charger via cig lighter for me on 3 cars with no issues.