Battery top up

[Retro Pedro]

Done my electric fork lift top up course yesterday (for company insurance purposes) and the instructor came out with this one.
Apparently, I would need to charge a battery up first, then when fully charged and if required, top up with distilled water.
Explanation given was that whilst charging, the liquid expansion process will occur giving off a gas. If top up occured after charging, the distilled water would then be at the correct level.
What do you reckon, true or false?

[Rich]

I think he is correct i remember topping up a battery and then charging it and the finding the fluid over flowing while it charged.

[fogman]

i thought the electrodes had to be just covered before charging

[Drift]

I work for Linde fork lift trucks, we just top them up and charge them and top up after if needed, this is 24v, 48v and 80v batteries.

We also build/refurbish batteries and its not as technical as you may think, lots of hammering involved

[Lenny1969]

Instructor is wrong. I'm an FLT instructor and national examiner and what should be done is battery topped before charging to allow for equalisation charge to pulse fluid from water into electrolyte, otherwise all you are doing after charging is diluting the electrolyte thus shortening the battery length time.

[Drift]

If the cells look dry or you can't see the water then fill and charge then top up and test.