I do not have any experience using solar battery chargers on electric beach wagons however since no one else has replied to this post I thought I would reply with what I know. First off I know that a solar panel should not be connected directly to the battery pack, there should always be a charge controller between the battery pack and solar panel so the batteries do not get overcharged. Solar panel charge controllers are available everywhere that sell solar panels and do not cost very much. Regarding solar panel size that depends on how many Ah the battery pack is and how long of a recharge time is desired. For example if the beach wagon has a 24 Volt 12Ah battery pack then a 24 Volt 35 Watt solar panel in full sun will recharge a fully depleted 24 Volt 12Ah battery pack in around 5 to 6 hours. A partially depleted battery pack would of course recharge in less amount of time.
12 Volt solar panels are more popular than 24 Volt so they might be less expensive to buy and be a better value. Multiple 12 Volt solar panels can be wired in series to make 24 Volt, 36 Volt, 48 Volt, etc. solar panels. When wiring multiple solar panels together to make a higher Voltage panel the Watts rating of the 12 volt panel is multiplied by the number of panels. For example two 12 Volt 15 Watt panels wired in series makes a 24 Volt 30 Watt solar panel.
Update: We now carry solar panels and controllers for 12 Volt, 24 Volt, 36 Volt, and 48 Volt lead-acid and LiFePO4 batteries and battery packs.
These solar panels and controllers can be found on this page:
I have put together a motorized beach wagon and I was wondering if anyone who did the same has used a solar battery charger? I take the wagon camping for 7-14 days and I figure I could charge it while it is sitting on the beach. Any suggestions on a charger would be great.