12vdc car battery charger

"solar battery maintainer" doesn't tell me much. Solar obviously refers to the less important aspect of how power comes into the charger, but nothing about the more critical aspect of how power is applied to the battery. Not only that, it sounds like it may not work well at night or in an unlighted garage. I guess I'll pass on that idea.

Not if you want any life from the charger either. It's goof dor about

At 6 amps the cables won't even get warm. They are roughly 14 gauge minimum. The ones with the 50 amp boost WILL warm the cables - duty cycle is about 30 seconds and 10%. 30 seconds on and 5 minutes off.

My old charger, very similar to the one in the OP pic, is rated at 4 amps. If the battery needs charging, then the current will ramp up to 4 amps, which is a trickle charge. As the battery reaches fully charged, its internal resistance will increase and the charger out will reduce voltage and current commensurately. Typically it drops to 1 amp or less and, on a typical 30-40 AH battery, that's a float charge and it is generally insufficient to damage a battery if left on full time. Sure, it is not *intelligent* and all the newer smart chargers have more charging modes, my smart charger having 4 or 5, but for most people the need for all these is minimal. The issue I found with some smart chargers is that they won't always correctly assess a battery's state. Mine is certainly like that whereas the old one always charges the battery regardless.

FWIW, while I have a charger capable of providing an intelligent float charge, I never leave it connected long term unless it is on a timer.

Whilst the alternator is capable of charging at rates of 30amps and upwards, It is never recommended that you let the alternator charge the battery if it has been flattened to any degree. The rule I was taught back in the 60s was you remove the battery from the car and charge it at the *safe charging rate* which was, IIRC, 10% of the amp hour rating of the battery. That ensures a long life. The alternator is designed to run the car electrics and it is not designed as a charger per se. That's why it is recommended that the car battery be occasionally put on a trickle charger now and then to remove sulphation and top it off to the correct voltages.

They are handy t have. I keep one in the car and one in the garage. The snag with those, if it can be called that, is that they need to be topped up every now and then, at least once every 3 months, preferably once every month.

I had two but I *foolishly* lent one to a friend and he dropped it. No wonder we call him passion fingers!

The underlying principles seem to make sense. Mine has the function and the last battery I had charged required pulse mode. I'll let you know how it went next time I need to top off the same battery.

Yeah, that's why I needed to use mine in pulse mode. Note, I had to force it into pulse mode otherwise live with it saying the battery was knackered.

I agree in a garage, maybe not so much but the sun shines every day if your vehicle is outside. It is plenty to keep a battery up with the advantage that it works without needing AC power where you are. No extension cords to screw with when you drive away.

Years ago I loaded batteries for recycling in Tucson. The guy had a lot of batteries on a pulse system. He would run the tradeins through the system and if they showed signs of life would sell them as used. Used tires were another big thing in that area. A lot of people were keeping their junkers running on fumes.

That's 600ma, nothing to sneeze at. It's not going to charge it quickly, but to maintain it where there is sunlight it would be perfect. Like if you have a car you're going to leave somewhere for a month or more. It also will charge it if you have enough time.

Maybe it's not idea, but millions of people do it. Battery drained, they get a jump start and drive off. I bet most of them don't get it charged by other methods. Even if it shortens the life by a small amount, the cost of that seems insignificant. Certainly is for those that can't charge it themselves and would have to go somewhere, pay them, have the car sit there for the charging duration, etc.

The rule I was taught

Remove it from the car?

That ensures a long life. The alternator is designed to run

That last part makes no sense. The alternator is constantly putting ~14V on it. I don't see what a trickle charger is going to do to a fully charged battery, nor do I see it removing sulfation.

Whatever works for you but 7.5w (0.625a) 5 hours a day (How solar collectors are rated) is plenty to replace the parasitic losses in a battery that is just sitting there.

It doesn't do squat for a dead battery but they should be charged if you drove it much at all the last time you used it. This has solved my dead battery problems in seldom used vehicles. I should sell one of the cars but I like mine, my wife likes hers and we still need a truck now and then.

If you took it to a mechanic shop they would hook it to their fast charger so it is a wash.

True - but every time a battery goes low and the car gets a boost, the alternator charges that battery and they still last an average of

Battery technologyAND charging systems have changed significantly since the 60s.. The biggest problem was with the small-frame GM alternatoe the high ampersge ones would fry themselves trying to charge the dead battery at 135 amps - - - -

Note what it says - Such technologies will lower the sulfation on a healthy battery.

So the idea is sound - and it DOES work - to a point. Once a battery is SEVERELY sulphared, virtually NOTHING will remve the sulphate. Pulse charge can extend the life of a battery that has been left partially charged for a little longer than it should have been but it can't "raise the dead"

I have not seen a reliable source that says pulse desulfation works.

A source I think is reliable for all types of batteries is battery university

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