trickle charger

Let's define our terms - in popular usage a "trickle charger" meant an old school unregulated "dumb" charger, they will boil a battery dry if they aren't disconnected when the battery reaches a full charge. A "float charger" or so-called "smart charger" is specifically designed to be left connected indefinitely.

The old school chargers like Sears and everybody sold were sized for the average car battery, at the 2 amp rate would taper down to almost nothing current rise, but the voltage is unregulated. In the summertime temperatures this does Bad Things to a battery very quickly.

In extreme cold it could probably be left connected for the duration of the extreme cold. The battery internal resistance will tend to limit the voltage.
 
Last edited:
Battery Tender makes a charger/maintainer that works on both 12 and 6 volt. I have several and have been very happy with them. You can find them online for around $60.
 
There are also smart battery maintainers that can convert the crystalline lead sulfate to amorphous lead sulfate. That will significantly extend the battery life. Look for desulfating battery charger.

The crystalline lead sulfate forms when the battery is partially discharged and cannot participate in the charging/discharging of the battery. It is one cause of reduced battery life.

I have killed more batteries by overcharging than anything else. It is important to have the right battery maintainer for your batteries.
 
It depends on the charger, whether its a charger and its charge rate, or, a maintainer.

Either way, if its going to used for any length of time I hook it to a timer for a hour or two a day.
 
If your car is going to be idle for extended period of time, just disconnect one of the battery cables. This has worked for me up to a couple of months, just make sure the battery is fully charged.
 
A battery will self discharge on its own because of a small amount of internal current. If you are going to leave it for more than a few months put a maintainer on it.
 
I use this on 12vhttps://www.amazon.com/Schumacher-SC1319-Automatic-Battery-Maintainer/dp/B0756Q88J5/ref=asc_df_B0756Q88J5?tag=bingshoppinga-20&linkCode=df0&hvadid=80745439395605&hvnetw=o&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4584345029241732&psc=1 and 6 v batt;s
 
The fellow I purchased the car from also gave me a trickle charger that he used on a regular basis. I will be away for a month and am worried about leaving it attached for so long unattended. If I don't connect it while away can't I just plug it in and wait until the light turns green indicating the battery is fully charged? By the way, what's the difference between a trickle charger and a maintainer?
 
What model charger do you have? Then we don't have to guess.


It is a DieHard battery charger model 28.71219. When I looked it up I found this model number but the picture showed a switch on it for 6 or 12 volts so mine must be an older version.
 
The fellow I purchased the car from also gave me a trickle charger that he used on a regular basis. I will be away for a month and am worried about leaving it attached for so long unattended. If I don't connect it while away can't I just plug it in and wait until the light turns green indicating the battery is fully charged? By the way, what's the difference between a trickle charger and a maintainer?

Kenjt,

Crankster explained the difference in post #2 above.

If you want to keep your trickle charger hooked up to your battery for an extended period of time the best thing to do is put it on a timer so it goes on for a hour or two each day and then goes off.

You can also charge your battery and then disconnect it. Even if you leave it connected, Model A’s don’t drain the battery unless you have a short in the system.

Personally, I would recommend buying a maintainer. I have a 6V/12V Battery Tender that I can use on my modern 12V cars as well as my Model A. They are not that expensive, you can leave it hooked up and you don’t have to worry about it.

David Serrano
 
That model is "automatic" and a "maintainer". It's smart. It should be absolutely fine to leave connected indefinitely, in fact that's what you want, it is designed to maintain a "float charge". If you measure it with your DVOM it will be somewhere around 13.10 volts or so, practically no current, this is just enough voltage to prevent self-discharge over time and permanent sulfation. That is what ruins batteries before their time. Will be charged and ready to go when you are, and also saves wear and tear on the generator or alternator.
 
Kenjt,

Crankster explained the difference in post #2 above.

If you want to keep your trickle charger hooked up to your battery for an extended period of time the best thing to do is put it on a timer so it goes on for a hour or two each day and then goes off.

You can also charge your battery and then disconnect it. Even if you leave it connected, Model A’s don’t drain the battery unless you have a short in the system.

Personally, I would recommend buying a maintainer. I have a 6V/12V Battery Tender that I can use on my modern 12V cars as well as my Model A. They are not that expensive, you can leave it hooked up and you don’t have to worry about it.

David Serrano


Thanks for the suggestion. The idea of getting a timer is great. It sounds like a real safe option and a lot cheaper than getting a new charger. The previous owner installed a cable to the battery that comes out by the seat bottom and make it very easy to hook up to the charger. I'd rather not redo this.
 
You don't need a timer for that charger.

I know this sounds crazy, but ... have you read the Instructions?
 
Let's define our terms - in popular usage a "trickle charger" meant an old school unregulated "dumb" charger, they will boil a battery dry if they aren't disconnected when the battery reaches a full charge. A "float charger" or so-called "smart charger" is specifically designed to be left connected indefinitely.

The old school chargers like Sears and everybody sold were sized for the average car battery, at the 2 amp rate would taper down to almost nothing current rise, but the voltage is unregulated. In the summertime temperatures this does Bad Things to a battery very quickly.

In extreme cold it could probably be left connected for the duration of the extreme cold. The battery internal resistance will tend to limit the voltage.

Mine doesn’t….’boil’, it shuts down !
 
The advantage of the Deltran Battery TENDER smart charger is that it will not over charge your battery. It lets it drop to 85% charge and then it brings it up to 100%. I have all my cars on them. A 3 year 6volt Model A battery once lasted me 10 years with these, and your Model A is always ready to go.
 
You don't need a timer for that charger.

I know this sounds crazy, but ... have you read the Instructions?


Yeah, I did find the instructions online but it doesn't say anything about how long it can stay hooked up. The idea of a timer (as above) is really great and that's what I'll do.
 
Back
Top