Stanley, 6, 12, 24, 36, 48 volt SMART Golf cart battery charger

[Logan005]

I recently purchased a Stanley SMART Golf cart battery charger. It is designed to charge AGM, FLA and Gel batteries. It took 2 weeks of outdoor well ventilated use to get rid of the awful chemical smell, but now seems to be an amazing charger. My main concern is in AGM mode, it seems to exceed the recommended charge voltage, I see it read 15.2 volts at times. as I recall this exceeds an AGM battery design. Please advise as I do not want to ruin any of my batteries.

[PNjunction]

Yes, under normal circumstances, 15.2v is too high, but I suspect that the undocumented charge algo of the Stanley may be doing what's known as an IUI, or perhaps just a small zinger to 15.1v very rapidly at the end.

Only YOU will know if the GBCPRO's undocumented charge algo is going to kill your agm.

When exactly does this rise to 15.2v occur? Does it happen near the very END of absorb (when amperage is falling)? How long does it stay that way at 15.2v?

Understand that charger is primarily meant for very short turnarounds of golf-carts, where one may not have the time to allow for a minimum of 8 hours of float to actually finish a charge (common misunderstanding about agm). So, to compensate, it may be doing what's known as an IUI charge algo that goes back to a CC mode AFTER absorb is done for an hour or so, which entails raising the voltage. That is usually 15.5v, so I suspect this 15.2v is just a short zinger.

(Some other automotive "speed chargers" also do this IUI behind your back [even hiding it behind a false voltage in the display], but in certain circumstances, they bring it on too early by not allowing for absorb to actually finish, and it just gasses the hell out of your precious agm. Fortunately, I've found Stanley's to be a bit tamer and more usable).

Batteries like pure-lead Optima's actually can do this alternative IUI where short turnarounds and lack of float-time are the norm. Some UPS-style agm's cannot.

So grab a chair, a non-alcoholic beverage, your multimeter on "hold" or "max", and document the charge voltage while looking at the current.

I notice that the GBCPRO in the normal charge mode does NOT fall back to float under normal circumstances, but goes into a "float-monitoring mode" and only triggers back when a low voltage setpoint is reached.

So IF that charger is not truly doing an "IUI" charge, but just a small 15.1v zinger at the end, you'll want some way of actually doing 8 hours of float after all is said and done.

There appears to be a "maintenance charge" mode, which I would hope would be a 13.6v continuous float, which WOULD be ideal to do for at least 8 hours after finishing the basic charge, but with it being undocumented, you'll have to find out the hard way with your own metering.

If doing all this is just too much and you don't want to just cross your fingers, you may want to return it for a different charger that is FULLY documented, like a Samlex or other brand.

Another option if the voltages are just too high, is to *purposely* set it to GEL and document the charge yourself. Some consumer chargers may be too agressive with unusually high voltages for each chemistry, and purposely setting it to the wrong chemistry (gel in this case) may actually work better - your voltmeter across the terminals will be your guide as you document it yourself. This is not normally advised for those who do things blindly and do not actually measure things.

[Logan005]

I own a Samlex 24v charger installed as a UPS and it is a great charger and power supply for home security cameras and ATSC modulators. I am going to use meter to do some readings of the Stanley to find out more about it's set points and voltages. Will give an update. Thank You PnJ

[PNjunction]

When you take time to measure an undocumented charge algo yourself, sometimes you find that they DO get it right.

Of course, you may end up like I did with a pile of POS chargers that end up being recycled.