I want to know how companies who use solar panels on their cars utilise the energy generated by the solar panels.

Do they charge the traction batteries with the solar power or do they power the traction motors with it directly?

If they charge batteries with it then how they do it? Do they charge and discharge the batteries at the same time, or do they charge another set of batteries? If they charge another set of batteries to be charged by solar power then how do they extract that power?

If they power the traction motor with it then is it the case that batteries supplying only the extra power required by the traction motor left unfulfilled by the solar power?

If there is any case other than that please let me know.

I have asked these question after learning that some of the companies claim about 10,000 km under the most effective conditions.

  • \$\begingroup\$ which cars are you referring to? ... claiming 10000 km what? ... lifetime of the car? \$\endgroup\$
    – jsotola
    Jan 12, 2021 at 5:27
  • \$\begingroup\$ Yes, a lifetime of the car. I am referring to lightyear one. But I want to know how do they utilise solar power. \$\endgroup\$ Jan 12, 2021 at 6:23
  • \$\begingroup\$ According to the Lightyear One's specs it has a range of 725km, and goes 570km on 60kWh of charge - which suggests the battery has usable capacity of ~76kWh (sounds 'plausible', Tesla Model 3 is 82kWh). 10,000km/725km is only 14 charges. One would hope the battery lasts longer than that! \$\endgroup\$ Jan 12, 2021 at 6:37
  • \$\begingroup\$ @BruceAbbott I mean by 10,000km is that batteries can be charged by solar panels for a 10,000 km in the lifetime period of the car. It does not mean that batteries can be charged 14 times only and that is their lifetime. \$\endgroup\$ Jan 12, 2021 at 7:19
  • \$\begingroup\$ @TusharDubey why don't you do a bit of research about solar cells and answer your own question? \$\endgroup\$
    – jsotola
    Jan 12, 2021 at 8:11

1 Answer 1


The simple answer is that when there is both sunshine and a charged battery, both can be used simultaneously. Any combination is possible with the right control electronics, so it will differ depending on what the manufacturer wants to happen. The battery will always be the more powerful unit, so when solar panel and battery are both available, the solar panel will probably be used to supplement the battery power, so the battery will not discharge as quickly. Charging and draining simultaneously doesn't even make sense, but alternating between them can. For example, regenerative brakes charge a battery but then the battery drives the motor after braking has ended.

In a solar powered car with a battery, a few hours parked somewhere will charge batteries enough to get to the next parking lot, maybe. The difference between battery capacity and solar cell capacity is that big, and it always will be because the biggest limitation is the amount of energy the sun delivers per square metre, not the efficiency of solar panels. If all solar panels became 100% efficient tomorrow, electric cars would still need batteries, and the sun would still go down at night.

  • \$\begingroup\$ So when the batteries and solar power both are used simultaneously to drive the vehicle and batteries starts draining slower, instead of when batteries were the only source of power, as solar power gets available. So do batteries will do this behaviour automatically or we need to put electronics so when solar power is available battery should drain slowly? \$\endgroup\$ Jan 12, 2021 at 10:18
  • 1
    \$\begingroup\$ No, the car already has those electronics as part of its controller. Even the slightest bit of research will show you it's always draining the batteries while moving (well except maybe at walking pace on a sunny day) - just not draining them quite as fast as without solar. And you'd need to park it for about a week to recharge from solar alone. \$\endgroup\$
    – user16324
    Jan 12, 2021 at 13:51

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