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Old 05-09-2021, 01:15 PM   #29
Badcaps Veteran
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 2,467
Default Re: Harbor Freight car battery chargers any good?

Originally Posted by caphair View Post
Seems to be working ok so far. Checked this morning and the display is green and displaying 13v

After removing the charger the voltage on the battery with a dvm reads 13.12v is that normal right after a charge? Not used to seeing anything greater than 12.7v
It's normal for a lead-acid battery to have a "surface charge" which reads as slightly high terminal-voltage right after charging. It will drop down to around 12.8V at 100% state-of-charge.

The Harbor Freight 63350 charging voltages are all look too low There's no evidence it does the top-up to >14.4VDC, it does not do an equalization charge (flooded types need that) and a float voltage of 13.0V is way too low which is a problem.
This means it's charging the batteries to say 80% but doing nothing about sulphate build-up.
If you float a car battery at 13.0-13.2V it has a short life because of sulphate build-up and lack of equalization charge. Most people won't notice.
If you don't believe me, look at car battery datasheets, charging info. I have collected Exide, Trojan, US Battery, Panasonic, Magnavolt, Victron, Powersonic charging voltages. They are largely the same amongst the different chemistries such as lead-calcium, antimony, AGM etc.
Flooded PbCa is charge to 14.7V, float at 13.8V, equalize at 14.7-16.2V 1-3hrs every month. Value depends if deep-cycle, marine, starting etc. A good boil.
AGM/VRLA/Gel is charge to 14.4V, float at 13.5V, strictly no equalization unless really old and beat up.
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