https://www.amazon.com/Xtreme-Charge-XC100-P-Maintenance-Desulfator/dp/B001JSTM8I

This is the battery maintainer that I use on my 12v cars and airplanes. As long as it is a lead acid flooded battery (a normal battery) it works great. Even if the battery is totally dead this thing brings it back to life. I have the cheapest battery I could get in my 68 and it is still going. But once the battery is dead it s dead. It mightl start the car one last time but if you turn it off it's done.  PS This is not a recommendation for Amazon. I'ts just what came up first.

I have something that's similiar to the Amazon link that I got from Home Depot at Thankgiving for $20 bucks. It's been on Sheryl's BMW ever since. It took several das to get the battery fully charged. I haven't  checked it in several month, guess I should take a look to see how to doing. 

Battery Minder...and if you have an alarm system, modren radio, efi, cruise control, Vintage Air Gen IV system or anything else that requires "Keep Alive" power you'll definitely want to use one or some sort of battery trickle charger or at least disconnect the NEGATIVE cable.  Always disconnect the negative cable first.  Working on the Positive cable while the negative is connected can be very dangerous as accidentally getting a wrench between the cable and ground is the same thing as laying a wrench across both posts....not fun.

Also, most normal chargers including my Battery Minder will not bring back a fully discharged AGM  battery (Optima, Obital, etc.)  but will keep them nicely up to speed without damage over the winter.

BB
 

Once a battery is activated it starts to die. So it will die if it is not kept charged. And disconnecting it and walking away from it will not save it. It will last longer with a trickle charger on it. There are different types of trickle chargers also. Some continue to charge at 1 to 2 amps. That can over charge a battery if waked away from over a period of time. Others turn off when the battery is charged and turn back on when the charge depletes itself. Some desulfurization chargers don't turn off after the battery it brought back to life. If you are trying to desulfer a battery it might take a couple of days to a week. After week it's time to chunk it.

To answer your question Mike, first put an amp meter (like a real one,HF has em for under ten bucks, sometimes they are free with another purchase)
 Disconnect the neg cable and insert the meter beween it and the neg on the battery. If there is any drain at all, on your car there should not be unless you have some thing connected like an alarm system etc.
If no current is detected you might as well leave the batt cables on during down time.

 My next question is why on earth does that "hot rd" sit idle for a month at a time, the kind of weather you have in Surfside you should be out every day scarin lil ole ladies and stray dogs.
PS, don't waste your money on a HF trickle charger, they are junk.

 My red top Optima has been good for over ten years with the method I use. The car is down for each winter from late Oct. to mid Aplril. I have a regular 15 amp charger connected to a timer that comes on for a hour each day, it seems to be what the Red Top needs. During driving season I try to start it at least every two weeks if not driving it. I have an alarm system that does have a constant battery drain 24-7-365.
 Hope this helps ya Mike.

Last edited by Rudi (5/26/2018 2:18 PM)

Rufus68 wrote:

Who is GF?

Also, any modern radio has a memory and clock power draw.

Sorry , that should have been HF, Harbor Freight.
https://www.harborfreight.com/7-function-digital-multimeter-63604.html

Thanx fer the "input"!
  It rarely goes more than 2 weeks without at least a spin-around-town, Rudi.
I was just wondering about when we go out of town for several weeks at the time.

Really just wanted to post something (other than brakes, steering question!)

I do need to replace my battery disconnect switch so I guess I will do that soon.
6sal6

Alan wrote:

https://www.homedepot.com/p/Sunforce-1-8-Solar-Battery-Maintainer-50012/202218716?cm_mmc=Shopping%7CG%7CBase%7CD27E%7C27-31_CONTROL%7CNA%7CPLA%7c71700000034238969%7c58700003946879296%7c92700031953709695&gclid=EAIaIQobChMI8JeP7K6j2wIVkLbACh2CSAXREAYYBCABEgJF-PD_BwE&dclid=CLjCvoKvo9sCFRyvTwodUtABEQ

Would one of these keep a battery charged enough?

of your iphone maybe! :D I wouldnt think it could even trickle long and hard wnough to maintain a consistent charge in the 12V battery. .

I just bought a cheap self sensing battery charger off amazon .. which slowly charges up the battery . I leave it all hooked up , unless i am plannig on not driving for months