The store bought battery tenders or maintainers do a great job of keeping batteries fully charged without over charging. I have found these, friendly priced for from $21.50 to over $45.00. Does anyone out there have a schematic for one of these units, I would like to see if I could build one. I have a pile of used chargers from phones, printers and etc. that I think would be large enough to maintain a car battery. I have used a number of these to power solenoids and even windshield wiper motors in household applications.
Battery Tender Clone
- Thread starter callcoy
- Start date
Tom Wesenberg
Well-known member
If your transformers put out at least 6.7 volts you should be able to use them for a trickle charger/maintainer. Many already put out DC, so all you need to do is put a couple battery clips on the ends. If they put out AC, then you can go to Radio Shack and buy a small full wave rectifier to install on the 2 output wires.
Doug in NJ
Well-known member
So, how many milliamps should a trickle charger be trickling into the battery?
Doug
Doug
Mike V. Florida
Well-known member
Keep in mind that battery tenders like the one sold by Deltran monitor the battery and provide a charge only when needed, float mode. It is not a "trickle" charger.
If you have a trickle charger you might want to put it on a household timer set for 15-30 minutes a day.
If you have a trickle charger you might want to put it on a household timer set for 15-30 minutes a day.
Thank you Tom for your input, Mike, kind of hits on my concern but Doug really nailed it. I have chargers that convert to a trickle mode, I am looking to build a "Tender" that does not overcharge the battery, but floats. Meaning as the battery loses a little of it's charge it is gently brought up to a full charge condition, then the system shuts down, it doesn't stay on forever.