Trickle charger

[Rjscharer]

Have to leave car garaged for a month. Where is the best place to attach positive and negative cables from charger?

Thanks

[Kessler35is]

To the battery terminals.

That is where I always attach my pigtails for trickle chargers.

[jparnes1]

Originally Posted by Kessler35is

To the battery terminals.

That is where I always attach my pigtails for trickle chargers.

Def intely not the battery terminals. BMW's have a positive and ground in the engine bay. Don't mess with the battery.

[Rjscharer]

Much thanks...all hooked up.

[Kessler35is]

I'm talking about a pigtail. This lets you have a lead to the battery that is bolted on to the battery.

I have these on everything I own with a 12 volt battery, Truck, Car's, Motorcycle, Lawnmower, & Boat.


These are well known in the battery tender world and well trusted, they are even fused. It lets you hook up quickly and lets you close the trunk/hood of the vehicle.

Once you invest into a good charger just buy these @ about $6 per to outfit the fleet. You can buy tenders that can tend to 1,2,4,10 12V batteries at a time.

Because I keep anything in the garage on a tender 100% of the time the batteries in my equipment last a long time. My Motorcycle battery is over 5 years old and holds a charge like the day it was bought, my lawnmower has a 4 1/2 year old battery in it. In my last truck it was 5 years old and the battery was perfect. Because I keep them hooked up I rarely ever have to buy a battery. I know guys at work that have to buy a new lawnmower battery every year, My buddy has been through 3 motorcycle batteries in 4 years before I could convince him and now he has not changed one in 3.

The only way you will use a tender is if it is convenient to use. If you have to drag it out, pop the hood, clamp on clamps you will get tired of all of that. Now, if you had an industry standard plug in your trunk and all you had to do was open the trunk, plug it in and the tender took over you will be more likely to use it often.

Also, by putting this on the battery terminals you are sure of the good connection, if someone trips over the cable it will just unplug and not rip the clamps off of those terminals under the hood and have metal clamps scratching your paint as they get ripped out from under the hood.

[jparnes1]

OK I see what you're using, but how is that more convenient? Are you saying the tender is always stored in your trunk, all ready hooked up to the pigtail, and all you do is plug it in? I guess I'm not sure how you're utilizing this.

[Kessler35is]

Originally Posted by jparnes1

OK I see what you're using, but how is that more convenient? Are you saying the tender is always stored in your trunk, all ready hooked up to the pigtail, and all you do is plug it in? I guess I'm not sure how you're utilizing this.

My tender has long SAE cables on it, plus you can add extensions to it for greater range, and add clamps to it for a vehicle that does not have the pigtail. I do this if i need to charge a battery that is not in something and it only has bare terminals.

I will say for every other vehicle it is much easier since I have the pigtail in a place I can reach with out opening anything up. I have not looked yet but there may be a spot to feed the plug outside the trunk through a grommet and then seal it up.

So on the Z4 I have it in the trunk above the cover. I open the trunk, plug it into the tender cord, close the trunk and leave it to keep the battery topped off. I like these because you can not hook them up backwards and I can use them on all of my batteries. You will also know ahead of time if the battery is not holding a good charge since at some point the tender will never go into maintain mode and stay in trickle charge the entire time. When you get that, it's time to replace the battery soon or it could be low on fluid.

[Mick70]

Originally Posted by Kessler35is

I'm talking about a pigtail. This lets you have a lead to the battery that is bolted on to the battery.
(...)

I also use a pigtail for similar reasons.

However, please note that you should NOT attach the black (-) wire directly to the battery: The "IBS" ("Intelligent" battery sensor) is located directly behind the (-)-terminal of your AGM battery (see here, unfortunately in German). If you bypass this sensor, it cannot recognize anymore if you charge the battery at night and will possibly regulate in-drive charge cycles not correctly ("efficient dynamics").

So you should attach the black wire of the pigtail to the car body, e.g. as shown in the attachment (the picture shows the battery compartment in the trunk, directly behind the battery; the screw drills into metal, not into plastic).

Best regards

Mick

[Kessler35is]

Thanks for the info, I'm good with putting the ground on the chassis.