My 40 year old steel case 6 amp automotive battery charger finally died. I only want to replace it (and I don't want a contraption that jumps cars).
I just want a new 120VAC simple sturdy 12VDC automotive car battery charger. And I don't get out to the stores much lately.
Mine had an analog meter, and a 6V/12V switch (which I never used at 6V). If they still come with an analog amperage needle, that would be nice.
Any advice where to get a good simple sturdy 12VDC battery charger online?
Like these?
Ditto. I have one very similar but 4 amps rather than three and I have had it for close on 40 years. No smarts on those. They will however not overcharge a normal sized (30-40AH) car battery. In fact, the normal/safe charging rate of a lead acid battery is a current rate of
25% of the amp hour capacity of the battery. So 10 amps for a 40 amp hour battery. Therefore charging at 3 or 4 amps will take a lot longer but will not damage the battery or gas it up. My charger typically drops the current to 1 amp or less once the battery is charged.A problem I have found with the so called smart chargers is that they can't handle a battery that is close to flat. I do have a smart 6/12V charger and it is handy for some 6 volt batteries I have. The one I mentioned above only does 12 Volts which, up until recently, was all I ever needed.
I guess they didn't have to be smart to do that, just skillful!
I think the most recent 6V battery we possessed was for the 1960 Ducati Monza.
Nah, battery resistance increases as it charges cutting down the current. No skill required.
I have a couple from battery backup devices, one such being the NBN battery backup box. The charger in the battery box isn't the best and, every now and then, the battery low warning light comes on so I remove the battery, give it a charge on the smart charger up to 12.7-12.8 Volts, plug it back in and have no further issues for a few more months.
I use an old computer 350w power supply as a battery charger. It works quite well.
A trick I picked up somewhere along the way for smart chargers and dead batteries: if you wire a charged battery in parallel with the dead battery, the charger will operate as expected. You can disconnect the helper battery after a few hours to finish charging the dead battery alone.
Tom
Yeah, I thought I might need to resort to something like your idea above but I left the smart charger connected for quite some time and it eventually started pulse charging. I will know next time I need to top it up whether the pulse charging and trickle charging have worked with that particular battery.
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