A 12V battery that is not correctly maintained above 12.4V will suffer from sulphation, which the main cause of battery died. That's why the vehicle battery easily goes to dead when vehicles are left sitting for too long.
eBay
1000W Solar Folding Panel Portable Bag USB Output Solar Charger Outdoor Power Hiking Camping Power Generator Home Mobile Phone
Aliexpress UK
【What’s Included】ECOFLOW 110W Solar Panel, solar cable connector for different connection ports. 【Upgrade High Efficiency】 Compared with other solar panels, with the chainable feature enables you to chain a maximum of more ECOFLOW 110W solar panels together with the solar cable.
eBay
USB Solar Panel Charger Portable Battery Mobile Phone Charging Bank Charging Panel for Phones Fans Flashlight Small Power Banks
Aliexpress UK
100W Solar Panel Only. 1x 100W Solar Panel. Maximum Power (Pmax): 100W. Output: USB 5V & DC 12V. 1x Battery Clip（Alligator clip）. Maximum Power Current (Imp): 1.2A. Before we solved your problem, pls don't open any case.
eBay
JMUYTOP Solar panel 5V Portable Foldable Waterproof For cell phone power bank Charger outdoor camping True wattage not false
Aliexpress UK
Luminous flux: 90lm. Solar panel: 3W. Type:Solar System/Kit. Power Source:Solar. Colour:As the picture shown. LED bulb power: 0.9W. LED color: White light, 6000K-6500K.
eBay
20W Foldable Solar Panel 5V Portable Battery for Phone PC Car RV Boat Charger USB Port Outdoor Waterproof Power Bank Sunpower
Aliexpress UK
IP67 Waterproof The solar panel's IP67 waterproof protection allows it to withstand even the harshest weather and your adventurous lifestyle. 1.5X Higher Energy Conversion Efficiency Monocrystalline solar cells and a powerful sunlight-trapping surface provide a conversion efficiency rate up to 23%.
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Dc7909 Female to DC8020 Male Adapter for Solar Panel RV Portable Power Station
Aliexpress UK
[Power All Your Essentials] With an output of up to 1000W, run 9 essential appliances simultaneously without worrying about overloading. With a whole host of ports, from 500W AC outlets to USB-C, we’ve got all your device’s plugs covered.
eBay
Solar Panel Bag Portable Lightweight 30W 5V Mono Waterproof Foldable Charger Outdoor Emergency Hiking Backpacking Camping
Aliexpress UK
HIGHLIGHTS For VTOMAN JUMP 600X Portable Power Station - 600W | 299Wh. 【600W Constant-Power Power Station】 VTOMAN Jump 600X solar power station with 2 AC outlets for rated 600W(surge 1200W) output power.
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30W Solar Panel 12V Portable RV Waterproof Photovoltaic Charger Kit Car Anti-loss Trickle Polycrystalline Silicon
Aliexpress UK
Model: Crimper Crimping Pliers. Type: Solar Crimper. Features: MC4 Wire Crimper+Connectors+Spanners. Wire Crimper Length: 220mm. 1x MC4 Wire Crimper. 10 Pairs MC4 Solar Connectors. US - Wire Connectors.
eBay
6-fold Solar Panel Charger Portable Power Bank with USB 5V DC Outdoor Emergency/camping Travel Mobile Energy Kit
Aliexpress UK