Harbor Freight Float Battery Charger

[Bob_Roller]

I got a coupon for a float type battery charger from Harbor Freight, went to the store and purchased it yesterday .

I checked the box, and it stated that is was for use on gel cell type batteries .

I read the instructions, and it stated that the charger was not to be used on gel cell or AGM type batteries .

All of my batteries are either gel cell, or AGM type .

Anyone in the US have any experience with these chargers ?

[Barry]

The thing to do is measure the output voltage of the charger connected to a fully charged battery and see if that is suitable for the type of battery you have.  It won't do any harm in the short term.

Using an internal pot I have adjusted the float charge voltage and auto charge voltage on my charger to 13.65V  and 14.4 V respectively to suit a standard wet battery. I think the voltage requirements for your batteries may be a little different even from each other.

[Bob_Roller]

I removed the Odyssey battery (gel cell type battery) form the '84 LS this afternoon, it has a placard on it stating the float charging voltage should be in the 13.5-13.8 vdc range .

The owners manual for the float charger states a maximum output voltage of 13.2 vdc .

I'll charge the battery overnight on my normal charger, then tomorrow after work, I'll connect the float charger to the battery, and see what kind of voltage I get .

[Rob Valdez 79 R65]

My experience with AGM (Odyssey?) is that they like their juice in high amperages for shorter periods, like say, no more than an hour.

I use my Sears "2-10-Start" charger set on the 10 Amp setting.


Odyssey owners manual:
http://www.odysseybatteries.com/files/US-ODY-OM-006_0208.pdf

[Barry]

The owners manual for the float charger states a maximum output voltage of 13.2 vdc .

13.2 V is often quoted as being the correct float charge voltage for standard wet batteries although there doesnt seem to be any clear consensus and it always best to check the manufacturers recommendations. It does explain the comment in your instructions.

My 13.65 volt setting is a little high for a wet battery but would be ok for other types. I was aware of that but can't adjust it independently of the 14.4v auto charge voltage which would end up at 13.95 and that would then be too low.

Here's the bottom line for Odyessy batteries taken from Rob's link

"Trickle chargers that do not have a regulated trickle charge voltage between 13.5V and 13.8V (no lower than 13.5V and no higher than 13.8V) will cause early failure of the Battery and void the warranty"

I don't understand by what mechanism 13.2 volts could damage one of these batteries other than by not maintaining it quite fully charged. They are the experts though.  

[Bob_Roller]

I charged the Odyssey battery overnignt, with my normal battery charger, the voltage was 14.3  vdc ,

Put the float charger on it at 0500, just before I left for work, 12 hours later, the voltage is 13.3 vdc .

I'll leave the float charger on until tomorrow evening and see what type of voltage I see .

I'll experiment with this battery, as it's a little over 5 years old, way beyond warranty .

I removed it from my oilhead a few weeks ago due to slow starter operation, so I know the battery is in it's final stages before quitting it's 'day job' !!!

[Bob_Roller]

The float charger has been on for just a bit under 37 hours, battery voltage is 13.31 vdc .

Charger uses 2.8 watts of power .

[Barry]

It would be interesting to measure the open cicuit voltage after allowing the surface charge to dissipate.  I think 12.8 volts would indicate a full charge on those batteries. 12.65 Volts is more typical on wet types.

[Bob_Roller]

I'll put the float charger back on the bike after I get home from work today .

Weather forecast for tomorrow is an all day rain event/thunderstorms, so the bike won't get ridden on Sunday .

I'll leave the charger on a few days, then remove it, let it sit a day or two, and check the voltage .

[Semper Gumby]

Be careful with your Odessy batteries.  If your charger puts 15 volts or more it will damage the Odessy Battery.  That gets expensive quick.

Caveat Emptor!