I am troubleshooting a GTO/PRO 1000 automatic gate opener. It uses a 12 volt lead acid battery, kept charged by a trickle charger. The trickle charger puts out 1100ma @ 18 voltsAC, which is fed into the control board where it is changed to between 12.0 & 14.8 volts DC at the battery. The charger output (to the board)is within specs, but at the battery there is only 10.5 volts. The manual says to check the charging voltage with the battery hooked up. My question is, if the battery is bad or has a bad cell etc, could it affect the charging voltage reading, causing it to read lower than it actually is? When I checked with the battery disconnected, the charging voltage is still low, but again, the manual says to check with the battery connected. I did not have a new battery with me. My thought is to bring a new battery and a new board when I return, but I would hate to go to the trouble (mail order) and expense of the board if it is not needed.

It seems like if I stuck in a new battery, the charge voltage test would show ok since it would read the full voltage of the new battery.

What is your voltage at the battery with no load or charger on it? Usually once they drop below 8 or 9 VDC the cells are shot and will never hold a full charge, from my experience. Your ideal charging voltage for most lead acid batteries is 13.8vdc. If you have a bad cell or something else is wrong internally with the battery it could drag the charger down.

The battery voltage is around 10.5 volts. When you say a bad battery can drag the charger down, do you mean permanent charger damage or just a low reading when testing?

BigB
FWIW - Is this a new installation? I just wired two GTO openers (new installation) both units came with batteries showing low voltage (around 8V) They didn't seem to take a charge properly. Both sets of gates would not operate until I replaced both batteries with fresh 12V 7AH batteries. My guess is they sat on the shelf too long.
TCS

[This message has been edited by TwinCitySparky (edited 12-11-2006).]

No, these gates are not new. I replaced the battery for them about a year ago. I just want to make sure when I put in the new battery it will charge. This customer is a Loooong drive way out in the sticks, I don't really want a callback. I guess the smartest way would be to just go ahead with the new board and battery as a guarantee. I called tech support but they don't call back the same day.

Thanks

That sure sounds like a dead cell in your SLA battery. The thing is that you should usually get more than one year out of the battery unless it is in a hostile environment. Temperature extremes? Unregulated charging above 14.5 volts? Your DC might read low without a good battery if your trickle supply isn't filtered. I guess you could keep a 1000uF, >= 25 volt electrolytic cap in the truck. If a large filter cap on the output provides the proper voltage, a new battery is probably all that you need.
Joe

Check battery first, first charge it using a suitable charger (not the board you are dealing with), check voltage should be about 12.5 to 14 V), then disconnect your car battery from your vehicle and hook the SLA battery up to your vehicle (already warm) and watch voltage as you power up the accessories in your vehicle (dont try to start vehicle) - if voltage drops below 10V while trying to power accessories (fan blower, dash, interior lights and headlamps) you have a defective battery.

Thanks Ann but that sounds like too much work!

Tech support called and when I read them the various readings he said: "The board is bad". So a board and battery it is, at least this way I won't have to make the trip out there for a while.

Altho it is kind of nice to go out to the sticks once in a while. So far I have fixed their remote controlled roping chute, their hot walker and two automatic gates. Not to mention installing HPS lights on top of fold down poles for the roping arena, where they practice for the rodeo.