Hi guys. I've topped a lead acid battery to the upper level, stuck it on trickle charge till fully charged. It's fallen to the lower level now... When I top it up to the upper now do I have to charge again or should I be alright? 

Bye for now, Louis

What did you top it up with ??

lager, now the head's gone lol

Put a meter on it ,see what voltage is in it ,                             and stay off the Lager

Personally I'd just check it with a meter and stick it back in the bike, you shouldn't have to charge it once it's back in the bike/being used often 

You don't trickle charge till its fully charged. You charge a battery or maintain it.

Trickle charge is a waste of time. Once a car/motorcycle battery has dropped below 85 to 90 % its officially fkt. It may well appear to work for some time but its performance will start on a downhill. Unimportant on bikes like mine where the battery has little worth as far as high demand is concerned but anything with electric start will struggle.

You need to check the resting voltage with a good voltmeter. You should see roundabouts 12.2 to 12.6 for a good battery. Under 12 and there are problems, under 11.5 and its a door stop.

Also, you shouldn't charge a bike battery with a car charger, the current will be a lot higher than the battery is designed for, even 'low' on a car charger can be too high. Explains where your acid went.