I’m going to attempt to list all of our possible options below:
- Seasonal variance factor for solar power - disable solar panels for winter, halve for autumn and spring. Something more advanced, a combination of weather and season?
- Reduce battery capacities.
- Increase power consumption rates for common devices (kitchen unit, fridge, welder), or all devices. Or really jack up the consumption for some rare but likely devices that the player is bound to need at one point, such as the eletric forge, which might damn near drain a storage battery or two.
- Lower the number of batteries that can be installed on any one vehicle. Possibly more incompatibilities for storage batteries against other parts (floor trunk). Disallow installation of multiple battery types in one slot.
- Electric motors and vehicle weight: increase the power consumption curve. After certain mass, the engine power consumption becomes increasingly intolerable and difficult to manage. (exponential curve)
- Make solar panels more rare.
- Make alternators less efficient.
- Make storage batteries fridge-like blocks.
- Alternative energy sources: gas stoves (propane? hydrogen?). Then jack up the electrical stove power consumption.
- Separate battery recharge efficiency and solar panel efficiency - Allow solar panels to power devices directly (during sunny summer weather). Then hamper the battery recharge rates.
- Introduce batteries of various quality - the best batteries would be more rare. Batteries would differ in recharge rates and capacities. Low-end or makeshift batteries could even have passive discharge rates, unable to hold charge properly.
- Make solar panels irreparable. Or allow repairs only with spare solar cells instead of just a magic welder.
- In fact, nerf the welder and start demanding resources for vehicle repairs. (Too off-topic?)
- Introduce solar panels of various efficiency and/or power, just like engines come in various displacements (liters). Solar panels could come in 100W increments. Randomly found vehicles should only have panels of one type. Usually.