This is going to sound lazy... But I don't think I'd understand the specs... ?Your solar panel is shown as 1.5W, 24V. That gives .063A. If the charge controller draws say 10ma, that is 1/6 of your energy budget. Your energy budget is tight enough with out that. I suspect that others are correct - no charge controller is required. A .063A source is not going to over charge any SLA battery.
You did read the specs on the charge controller?
The problem here is that the maximum charge current for a typical Flooded Lead Acid battery is .1 C where C is the 20 hour amp-hour capacity. If you are applying a constant current maximum charge (from an unregulated PV panel) you do not want to exceed .1 C but you need to recharge the battery fully within a roughly 6 hour period of peak sun. That means that you will end up with a large battery that is only partially discharged. But if you size the battery and panel for reliable recharging during winter conditions (maybe 4 solar hours per day when weather is good) then you arel likely to overcharge the battery to some extent in summer unless you have a charge controller that limits the float voltage.To continue with Jon's post, for flooded lead acid batteries, if the charge rate is below a certain percentage of battery amp hour rating, then you don't need a charge controller since the charger will never overcharge the battery. I dont remember the figure, you can probably Google it easily. Think of those motorcycle trickle chargers that you just leave on continuously. They put out about an amp. You can get a small simple chsrge controller from a place that sells solor/off grod equipment like backwoods solar.com.