You say it is a 12volt 50 Amp=> 0.6kWh battery, and that is quite small
But it is a 25volt 50 Amp => 1.2kWh lifePO4 battery what can comfortably go to 80% rate of discharge
seems to me a reasonable size
I think you are mistaken: https://blog.epectec.com/lithium-iron-phosphate-vs-lithium-ion-differences-and-advantages
(FYI, the spec says only 2000 cycles lifePO4 for this trolley)
Life Cycle Differences
Lithium iron phosphate has a lifecycle of 1,000-10,000 cycles. These batteries can handle high...
That is the MPPT, if will find the most optimal current and voltage for the panel. You use that number to get the right panels and if you put them in paralel or in series (3*300w, 10A panels in parallel it seems)
The number for charging time would be the 840watt it can maximal take from the...