ipanda x-plorer mppt input voltage/tracking issue

[fabieville]

I have a ipanda x-plorer mppt 60A. I notice that it has a input/tracking voltage issue.
I have (2) 24v 320watt panels in series giving me around 70volts on my input and i am charging a 24v SLA battery.

In full sun my input keeps on fluctuating between 50 to 60+ voltage at a fast pace and sometimes it drops to as low as 28volts and stays there for a very longtime before it goes back to fluctuating between 50 to 60+ voltage in full sun.

Is there a way to solve this issue by updating/flashing the firmware of the controller. If yes could you send me the file to update it or what else can i do?
I await your response anxiously. I really love this controller but the voltage issue is giving me a hard time . I am losing out on a lot of wattage most of the times due to the fact that the input voltage is not steady and keeps on running up on down even thou i am getting a steady full sunshine with no shading effect.

If i put a big 100v 15000uf Capacitor on the input would that solve the voltage sagging issue?
it appears to have a tracking issue within the firmware.

[bcroe]

If you have a good MPPT control, it will vary the input voltage (by drawing varied current) to
stay on optimum power transfer. And if output current needs to be limited, it will raise the
input voltage. Do not put a big cap at the input, as this will interfere with regulation or
possibly stress it. I would instead observe the output current and see if it is following the
prescribed charge routine. It should with strong sun, if not then look for trouble. Bruce Roe

[Mike90250]

Many low quality ( and some high quality ) charge controllers have trouble with partial sun/clouds variable . They often get stuck at a non-MPPT point and I have one i have to set manually of 70% PV voltage for tracking.