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Old 05-09-2021, 02:50 AM   #24
Join Date: Nov 2016
City & State: Bulgaria
My Country: Bulgaria
Line Voltage: 230VAC 50Hz
I'm a: Student Tech
Posts: 937
Default Re: Harbor Freight car battery chargers any good?

Originally Posted by redwire View Post
One review had blown capacitors, another said it's actually 12V 2A and 6V 4A so around 25W. The "4A" label is misleading.
That's the problem - a low battery will overload any charger and chinese stuff is already pushing parts too hard and poof.
Here is equivalent Lidl charger
And SMPS has good efficiency and usually small SMPS are able to provide good/adequate currents.
Originally Posted by eccerr0r View Post
depends on the battery of course.
Though at 2A it could take a day to charge some of the bigger batteries. However at 13.8V it should be about full, though it may still be in absorption phase.
Last time my battery was depleted by leakage currents in my car, with this kind of charger it took me almost a day to charge it up to acceptable level. 72Ah...
3Ax8=24Ah. 3Ax16=48Ah. At this point the battery was sufficiently charged, so the car can start without any problems. The rest of the capacity the car alternator restored after driving out of the town with 80-90km/h.
But I love to buy batteries at least 20% bigger in capacity than what the car really requires and it is recommended. If the manual says at least 48Ah, I will install 62Ah. If it says 52Ah or more, I will directly put 72Ah. The price difference between the capacities is not that large and usually putting the biggest battery that fits guarantees you that when the battery becomes worn off and it's capacity drops, it will not drop so quickly below the point, where the battery is still adequate to start the car.
Some people say that this overloads the alternator. But the simple logic shows that if you consume 10Ah from 48Ah battery and 10Ah from 72Ah battery, the alternator in both cases will need to restore exactly 10Ah. But in the first case it is about 1/5 of the capacity and in the latter 1/7 of the capacity. And during the winter this is significant. And if you deplete your battery significantly, you have to charge it with external charger anyway, unless you plan to drive long distances soon. Or there is some kind of electronics/wiring malfunction in your car. That eats battery capacity. And this usually is radio, alarm, electronics not going to stand by mode or plain things like forgotten lights.
So, if you have battery problems too often, check the alternator - if it's charging adequately, the voltage it provides. Check for anything that drains it - radio not turning off and what the stand by consumption is by using mustimeter in amp meter mode. If everything checks out and it's fine, then it is time to replace the battery.
Useful conversions. I don't "speak" imperial. Please use metric, if you want to address me.
1km=1000m=100000cm, 1inch=2.54cm, 1mile=1609.344meters, 1ft=30.48cm 1gal(US)=3.785liters, 1lb=453grams, 1oz=28.34grams

Last edited by televizora; 05-09-2021 at 03:27 AM..
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