Haze Battery

Wilk0,

at their web site, max charge rates for HZY12-80 and HZY12-90 are 20 and 22A respectively.
Comparing this with another gel cell battery manufacturer's data, this is already at the high end as the other specifies a recommended charge rate of between 10 and 20% of battery capacity.
Charging it with a 25A charger can potentially lead to dry out of your valuable battery, as the charge cannot be absorbed quickly enough. The effect of this is an overproduction of hydrogen which is beyond the battery's recombination ability.

I'd either get another charger, or buy the same battery again (if the existing one is almost new) and charge them in parallel.

Good chargers have a selector switch which allows for two or more presets of maximum charge currents (I'm not sure about the ctek?).
Also, try to get temperature compensation with this. You want -18mV/deg based on 20 degrees, for your gel cells.

Best regards, batterymeister

If you had a multiple outlet charger you could charge each battery independently and that would also offset parallel charging problems if they crop up .

Alternately you could fit a split charge unit that can charge independently and control over volt back feed and monitor each battery individually.

The only complication of the split charge unit is all batteries must be in the same vehicle and all channels must remain connected to a battery at all times.

Ian