Battery Tender

[likeold]

Do you use a "Smart Battery Tender" for those weeks or months of non driving times? What amperage do you use on your six volt system?

[Morgan Wright]

No. I take the battery indoors for the winter.

[Bloo]

I use them. I don't remember how many amps. Start out fully charged and you don't really need much. I go for small ones. Small is good. No point in charging the battery more than necessary. They don't like that. I think at least one of mine is a 1.5 amp.

 

Before these tender things were common I used to use a "dumb" trickle charger, 1 or 2 amp I think, on a timer and just have it come on once in a while. @edinmass suggested using timers on tenders. I haven't implemented that yet, but I think it is a great idea.

 

@Morgan Wright , I keep mine inside in the winter too, but in my area that is about a 3 month snooze, and I would rather not let the battery self-discharge that much, because I won't remember to top the charge off.

 

Edited March 19, 2022 by Bloo (see edit history)

[Str8-8-Dave]

Deltran makes the original battery tender and the 6volt models like the older one I have are around 1.25 amps.  It is a transformer with some onboard electronics that plugs into the wall and comes with ring terminal quick connect harness.  Not sure you can buy the one I have, it may be obsolete.  I use it on my 31 Buick's 6 volt NAPA lead/acid battery which is now 4 years old, never needs water and is always up to the task in the spring.  I also use a 12v Deltran battery tender on the winter garage queens.  Batteries in my tractors, Kubota side by side, 2 Ford trucks have never had a battery replacement, some after 10 years in service.

 

 

[kingrudy]

About four years ago I saw an article about a solar charger from Harbor Freight. It was cheap (maybe 15 dollars) I have used that for the last four years on my lawn tractor. Every spring my tractor starts right up without any hesitation. I don't think that the amps could be more than 1.25. I figure this solar charger has paid for itself.

For my Buick I just disconnect the battery. My battery was replaced this year after 6 years of service. 6 volt Interstate.

Edited March 19, 2022 by kingrudy (see edit history)

[Jim Nelson]

Schumaker battery chargers are my choice.   I have the 10 amp unit that automatically senses which voltage your battery is.     I also have a 'schumaker  trickle charger with a max rate of 1.5 amps.    This unit has a switch on the front to select which battery you have.    ( 6v or 12v).    I also have a  small (china ) 6v - 12 v , 1.5 amp charger from the company - 'Leicester' that senses what voltage you are using .   It works on these systems :   AGM,  GEL, VRLA, SLA, WET and deep -cycle batteries.     M/N  EPA1020-0612.   Bought it thru Amazon.  ( around $20.00)   Now I bought extra hook up cables  to hook up the chargers to the  battery when the cars have the batteries  {UNDER THE SEATS}.   ( my 1935 has it under the floor boards and my 1937 coupe has it under the seat.   My '38' has it up front next to the engine).   This let me hook the chargers to the battery without -grumble grumble     taking the seats out etc.   All I have  is a cable that I attached to the battery directly and thevother end  is kept under the seat  so I can easily hook up the charger.   The cable is polarizing so be sure that the cable coming from the charger it correct.   The other end of the charging cable should be - neg - exposed and the pos is covered with some insulation to protect it.    Now when you hook up the other cable - be sure it is correct to the battery is correct.  For some reason I have 'assumed' the correct wire to each on the battery,  ooops  my bad as I'm fairly good electrically.   Hmmmmm.   Any way,  each car is hooked up using the extra cable - one end matching the charger plug and the other with 'ring' ends to the battery .    I keep my cars on trickle charging if I'm not driving them.   I am in Florida so year round driving is nice.   I get in, flip the ign. on,  turn on the fuel boost pump for about 30 to 45 seconds to fill the carb,  pump the gas  2-3 times and hit the starter.   Good every time and my batteries are always at max. every time I drive.  

 

[39BuickEight]

I have a few of these because I can switch between 6v and 12v for whatever I need it for at the time.  They used to be $17.95 on Amazon.  My regular $65 6v Buick battery from Rural King is now 12 years old and still works great.

 

Edited March 26, 2022 by 39BuickEight (see edit history)

[Matt Harwood]

As someone who burns through A LOT of batteries in the hundreds of cars that have passed through my hands, I'm not convinced that battery tenders do anything to extend battery life compared to simply disconnecting the battery. They're useful on cars with computers to keep the computers awake, but on analog cars we have about the same battery attrition rate regardless of whether it's on a tender. In fact, tenders sometimes tell us the battery is fully charged but it isn't, so we periodically unplug them and plug them back in to let them take another shot at the battery. In most cases, the battery is shot. 

[Dynaflash8]

I've been using them 100% of the time now for about 6 months.  The 12v one gets quite warm, but I haven't worried about the all of the 12v ones I have do the same thing.   The 6v one was green one morning when the batter was totally shot, so I guess what you say is true.  Maybe I'll just go back to the disconnect.  I disconnect the '39 every time anyway, regardless of the new wiring harness firewall forward, since it is in the house garage.

Edited March 20, 2022 by Dynaflash8 (see edit history)

[Gary W]

I use a battery maintainer about a week before I'm taking a car out that has been sitting a while.  My Ford Roadster is more of a summer car, and it sits pretty much from October to April.  The Coupe is my winter Model "A", and of course the Buick is year round.  I have a Model "T" that runs exclusively on magneto, but I do get under there every three to four months and put the maintainer on the battery.  But I don't use them regularly.  Just for "touch ups"

 

I do, however, have a master kill switch in my cars (except the "T"), and I do think that the total disconnect preserves the batteries.

 

This is the kill switch I use in three of my cars.  I mount them on the floor, inside, just in front of the seat.  Paint the handle to match your interior.  Easy on and off.

 

 

 

And this is the maintainer I use to bring the batteries up.  It does conventional lead-acid, gel, AGM....  I run 6V OPTIMA Red Top batteries, so I use the AGM setting.

[Century Eight]

I use kill switches on everything except my daily drivers.  i have two newer antique cars that will drain a battery in a week or two, and the older  ones have wires that I’m not going to trust.  All will start right up in a non heated garage after 6 or 8 months of sitting if I use the kill switch, so no need for a trickle charge.

 

My big concern is fire as mentioned just recently in other’s posts elsewhere on the forum.

[Bloo]

The whole point is to not let the battery get too low from self-discharge. Sure you can and should disconnect the battery, and that is a big deal if the car has things that draw all the time, but it does nothing about what is happening chemically inside the battery. All of them self-discharge.

 

If you let a battery sit around partially charged, or worse discharged for a long period, it is getting sulphated. Tenders are a tool specifically designed to get around this problem. Overcharging is even worse, and batteries that cannot be allowed to drain down at all, such as the ones in uninterruptible power supplies don't last very long. There has to be a happy medium, and the idea is to let them drain down a little bit but don't let them sit drained.

 

I've been using maintainers for a while now. From watching them I do think they come on too much, but the results have been excellent. They must not be hurting the batteries. There are some pretty old batteries around here. The 36 Pontiac's battery is from 2015 if I remember correctly, and hasn't shown any sign of weakness. Before I started using a trickle charger with a timer, and later fully automatic tenders, I was lucky to get 2 seasons out of a 6 volt battery. I use tenders on 12 volt cars too. If you think the tender comes on more than it should, put a timer on it.

 

 

Edited March 24, 2022 by Bloo (see edit history)

[likeold]

I use battery tenders on all my cars 6V and 12V if there going to be sitting longer than a few weeks. I need to replace my 6V for the Buick, its an older model and if the electricity blinks it will not autostart, needs to be unplugged for a minute then its fine. I just wanted to make sure the 1.25 amp was the best way to go, that's what I use on all my cars. Buick has been sitting for 4 months now which is typical for the winter, my buddy has had to go to the barn and unplug my tender 5 time this winter because of electric issues. All my other newer tenders restart fine. 

Also I put kill switches on all my vintage cars. I like the knife kind because there is no doubting its is disconnected.

Edited March 27, 2022 by likeold (see edit history)

[Old26Buick]

I use both 6 and 12 volt Battery  Tenders. The only problem I have had is if the battery is real low the tender won'y work. I have been buying them that has a charger it it also. They work very good on a very low battery. I have had my lawn mower battery 7 years and still going strong.

[hidden_hunter]

I use a NOCO genius 10 on my optima red, more so my car is ready to go whenever 

[Jim Nelson]

For those who take the battery inside for the winter,   bless you !    Removing the battery from my cars is a real pain.    Under the floor is one issue but my '38' with it being up front by the engine is quite difficult for this old guy.   I'm  almost  to old (79)  to lift it up and over the front.    So,  using a 'tender' with a timer ( I've not done it that way yet) seems to be the best option.   Florida does not let me test that option.    When I lived 'up north' where it got below zero,  I always put a 60 watt light along side my battery and a small cover to keep the heat.   Then with a trickle charger,  it seemed to be OK.      Good conversation for the upcoming driving season and provides good options for our old car batteries.  

[Barney Eaton]

Very good discussion on a subject that everyone has an interest.   They all seem to work so whatever works for you go for it. 

Just don't do nothing or you will be buying batterys on a regular schedule

[Brian_Heil]

Stay away from this type of shut off. 
 

Unless perfect and tightened until your hand hurts, they can cause starting issues of high resistance.  You have enough to crank but nothing left to fire the ignition and poor starts. 
 

I didn’t believe it until a friend shared his experience and I proved it to myself.  
 

I have upgraded to the knife switch style as shown above. 

[Brian_Heil]

And my two cents on battery tenders. 
 

I have not found that they extend battery life but they are a must with more modern cars that have stay awake electronics with parasitic losses. Easier than re-programming the radio, seat and HVAC settings. 
 

In my older cars I have the knife switches and the batteries ‘sleep’ disconnected in the attached garage. But I put the tender on each in the Spring to bring each battery up. Handy as you can leave them on for several days and not worry about over charging. 
 

I might also add I have had 8+ year life multiple times with 6V tractor batteries from Tractor Supply.  Optima is a fine battery but I choose to spend my hard earned funds more wisely. 

[likeold]

15 hours ago, Brian_Heil said:

Stay away from this type of shut off. 
 

Unless perfect and tightened until your hand hurts, they can cause starting issues of high resistance.  You have enough to crank but nothing left to fire the ignition and poor starts. 
 

I didn’t believe it until a friend shared his experience and I proved it to myself.  
 

I have upgraded to the knife switch style as shown above. 

Exactly the way I felt about this switch, plus I never felt comfortable it was 100% disconnected.

[likeold]

15 hours ago, Brian_Heil said:

And my two cents on battery tenders. 
 

I have not found that they extend battery life but they are a must with more modern cars that have stay awake electronics with parasitic losses. Easier than re-programming the radio, seat and HVAC settings. 
 

In my older cars I have the knife switches and the batteries ‘sleep’ disconnected in the attached garage. But I put the tender on each in the Spring to bring each battery up. Handy as you can leave them on for several days and not worry about over charging. 
 

I might also add I have had 8+ year life multiple times with 6V tractor batteries from Tractor Supply.  Optima is a fine battery but I choose to spend my hard earned funds more wisely. 

That is how I first learned about battery tenders. I had a 2005 BMW Z car that sat all winter and when I went to start it the ALT light came on and would not go out even after driving it for an hour. Battery seemed to have plenty of power but I thought I was looking at a new alternator, not cheap for the beamer. After posting on a BMW forum like this they told me to get a battery tender, so I did. After 12 hours of charging the ALT light went out never to come on again since I used the tender - good stuff!

[Larry Schramm]

On 3/27/2022 at 4:25 PM, Brian_Heil said:

Stay away from this type of shut off. 
 

Unless perfect and tightened until your hand hurts, they can cause starting issues of high resistance.  You have enough to crank but nothing left to fire the ignition and poor starts. 
 

I didn’t believe it until a friend shared his experience and I proved it to myself.  
 

I have upgraded to the knife switch style as shown above. 

 

Based on Brian's advice, I threw the one that I had away.