[beren]

Thanks Ian,Paul and Jase. Like yourself Paul I have a 2amp Projecter trickle charger that I use on a 17a/hr powertank and 35a/hr lead sealed battery, does the trick for these but from what I can gather a Gel battery requires these three phases of charging.....

Step 1 - Bulk Charge - The battery is charged at full rated output current of the charger until the battery reaches its final charging voltage, known as the absorption voltage. This step replaces 70-80 % of the battery's capacity at the fastest possible rate.
Step 2 - Absorption Charge - When the battery reaches the absorption voltage, the charging current is steadily decreased while the battery voltage is maintained at the absorption voltage. This step replenishes the remaining 20-30% of capacity.
Step 3 - Float Charge - When the charge is fully replenished,charger voltage is reduced below the battery absorption voltage and is held constant. This prevents battery damage that would occur if the voltage was maintained at the absorption voltage yet still allows the charger to supply current to make up for self-discharge losses in the battery. The charger also supplies current to loads connected to the battery, reducing battery drain.

Thanks Jase/Ian for the suggestions on brands, looks like you can pay handsome prices for the type of charger that covers the needs of this type of battery $100-$200 min :I'll probarly check out these two... Projecter model and from Jaycar

It would suit your large capacity 120a/hr battery very well - You'd want something with reasonable charge amps. I might add that thats an impressive capacity

Had enough of being caught short and a vunerable corrector plate to boot with the portable power output I have now, hopefully this will be the solution