Central Locking

Following my earlier problems with flat battery [You must be registered and logged in to see this link.] I've deliberately allowed my vehicle battery to discharge in situ for a couple of weeks. Again the central locking failed to operate but the LCD display showed the vehicle battery as having 9.8 volts.
Immediately I switched to Vehicle battery charging, the LCD indicated 13.8v and Central Locking was once again operative.

Now given I probably have a knackered vehicle battery, but should not 9.8v be sufficient to operate the central locking? Do I have a problem or is CL operation just amperage dependent?

Incidentally, Moderators, I find this site very useful and interesting. Most of all it's active! Many thanks!

Alan

Lead acid batteries used to be called accumulators. When they are charged they accumulate energy. They relinquish that energy by discharging it into a load.

The battery voltage is a reliable indication as to how much energy is available in the battery. The fully discharged (no energy left) voltage is 11.7v with no load or 10.5v when connected to a load.

The Sargent unit indicates the voltage under load. If the reading is 9.8v there is no energy left in the battery so it cannot deliver any current. Your battery will be physically damaged and will no longer accumulate a significant charge. It is a costly business to discharge a battery to exhaustion.

Peter

Thanks, Peter, for your explanation. I was not aware of the discharged voltage threshold, but am now!

I came to just that conclusion, that my battery was knackered, yesterday when I found the battery getting hot whilst under charge - so it's a new battery required.

I did buy a small 4W solar charger a month or so ago which was successful in keeping the battery charged, but not at fully charged as I had hoped, so it should do well on a new battery which I will NOT allow to become fully discharged.

Thanks again

Best wishes
Alan

btw I have a Bonus PDU 4M unit, not Sargent, which seems to be very poorly documented, although I see from an earlier post on this forum that a lady in Warwick is very knowledgeable, should I need it