Can Lead acid batteries be slow charged at C/10?

[treez]

Can Lead acid batteries be slow charged at C/10?
Then when fully charged, can they be trickle charged at C/20 or therabouts?.....and how do you know when the lead acid battery is fully charged so that you can transfer to trickle charge?

We wish to look into lead acid batteries for our emergency lighting application, as the 4Ah NiCad batteries that we currently use cannot be trickle charged with our DC current source which is 340mA to 400mA (i.e. the charger output current is poorly toleranced from unit to unit).
The NiCads will be damaged if we trickle charge them with this current source, -even if we PWM it ON/OFF repeatedly, so as to achieve the lower trickle charge current.

So we wish to look into Lead acid batteries, as we wonder if its more robust than NiCad.

 

[D.A.(Tony)Stewart]

Heat kills batteries, so NiCad shutoff by heat sensor is best. Lead Acid trickle charge is ok with fast rise time pulse best to prevent sulphation..

 

[treez]

NiCad shutoff by heat sensor is best

yes, i agree, though we are trying to avoid the expense of a heat sensor, which as you know, must be glud to the batteries themselves, and then wires must come back to the pcb from that sensor, and connect to the pcb....so theres the expense of another connector aswell.

Then there's the problem of what temperature do you indicate as being high enough to stop charging.........and of course, it relates to the ambient temperature, so one needs another temperature sensor, stuck outside the pcb enclosure, to sense the ambient temperature so that you can compare the battery temperature with the ambient temperature..........it all adds a lot of cost and assembly complications.........eg what if the assembler sticks the battery sensor on without properly thermally coupling it to the battery, etc etc.