Solar Panel and battery powered BLDC motor together

[Sunking]

ya, this car weight is just 90 Kg, and it will driven slowly , around 30 kmph.

I bet my golf carts can go faster and longer distance. Not too mention cost a lot less money.

[SunEagle]

ya, this car weight is just 90 Kg, and it will driven slowly , around 30 kmph.

Not only slowly but not very far. What is the battery size and voltage you plan on using?

A 12v 220 AH battery will probably get you a couple of hours of run time but then it will be pretty drained even with the solar panel helping.

You can put in a bigger battery but that 110 watt panel will then not be able to get it back to full charge even if it was sitting still and directly pointed at the sun. Add more panels for more charging and you add weight to the car which will eventually requires a bigger motor to move.

What is your full intent of this experiment. To see if an electric car can be run off a solar panel? Some Universities have done that already but their "car" was engineered to be light, aerodynamic to run smooth and covered in solar cells. You may be able to find out more details on those "cars" by doing some research.

[billvon]

ya, this car weight is just 90 Kg, and it will driven slowly , around 30 kmph.

You might be able to hit that speed with a 500 watt motor, with good tires on flat ground and a very low friction drivetrain. But it will be somewhat challenging.

[Magardion]

That must be either a very small car or a low speed car with just a 500 watt motor. Depending on your battery Ah rating even with that 110 watt panel I don't think the car will go far before the battery dies.

ya, this car weight is just 90 Kg, and it will driven slowly , around 30 kmph.

[billvon]

What happens when you come to a hill? Here I see people pushing the electric bikes to help them top even small hills.

Deals fine with most hills around here (San Diego.) It slows down considerably of course. There are a few off-road trails near me that it can't make it up at all.

[russ]

As a reference, I have a bicycle with an 800 watt electric motor. It weighs about 60 pounds. It will hit about 33-34mph on flat asphalt. So if you build a car with a smaller motor expect very low maximum speeds (10mph? 12mph? something like that.)

What happens when you come to a hill? Here I see people pushing the electric bikes to help them top even small hills.

[billvon]

Ohh thats my point, thank you for the explanation

So the truth is i wanna build electric car with solar panel as accessories, the motor power is around 500 watt

As a reference, I have a bicycle with an 800 watt electric motor. It weighs about 60 pounds. It will hit about 33-34mph on flat asphalt. So if you build a car with a smaller motor expect very low maximum speeds (10mph? 12mph? something like that.)

[Sunking]

So the truth is i wanna build electric car with solar panel as accessories, the motor power is around 500 watt,

Huh? You wanna build a car with less than 1 HP motor. I have toy RC planes with bigger motors. Heck my golf carts have bigger motors than that.

[SunEagle]

Ohh thats my point, thank you for the explanation

So the truth is i wanna build electric car with solar panel as accessories, the motor power is around 500 watt, and the solar panel is 110 watt, and i just use 1 battery, so i want to minimize the output energy of the battery with solar panel like the system i told

Thank you mr

That must be either a very small car or a low speed car with just a 500 watt motor. Depending on your battery Ah rating even with that 110 watt panel I don't think the car will go far before the battery dies.

[Magardion]

Ohh thats my point, thank you for the explanation

So the truth is i wanna build electric car with solar panel as accessories, the motor power is around 500 watt, and the solar panel is 110 watt, and i just use 1 battery, so i want to minimize the output energy of the battery with solar panel like the system i told

Thank you mr

[Sunking]

OK here is where you are getting lost. for any off-grid power system using batteries you have to determine how many watt hours you need in a day. Once you know that determines your battery size. So let's say you have a pump motor that runs 24 hours per day and uses 200 watts. That means the pump uses 200 watts x 24 hours = 4800 watt hours. If you use say a 24 volt battery will require 1000 AH 24 volt 2000 pound battery.

The panels must be able to generate what is used daily plus enough to over come system losses. At best a battery system is only 66% efficient. That means if you use 4800 watt hours the panels have to generate a minimum of 7270 watt hours under worse case conditions. So if you live in a area that only Recieves 4 Sun Hours in winter you would need a 1800 watt solar panel.

So in the day the panels supplies power to both the pump and charges the battery at the same time. Toward the end of the day as sun sets the panels generate less and less power. When the panels are generating less power than the pump is using th e batteries seamlessly makes up for the shortage and supplies power all night until the next morning when the cycle repeats itself.

[inetdog]

Hello Mr Sunking, thank you for replying my thread.
so, in this case, i dont use the LOAD terminal , but the CHARGING terminal of CC. and it will go to the battery. then it will paralelly with big load such as DC motor controller.

so i just wanna make sure that the system design is working. how do you think about that? if i had big load, it will need a big current, in my calculation, the solar panel and battery should work together to power the load.

True, but for a really big load the panel contribution will be small compared to what comes from the battery.
This affects wire sizes among other things.

[Magardion]

You get nothing. The LOAD terminal on controllers are pretty much useless. The are for very low power gizmos like a LED light. It is just small relay with a fuse, and a LVD that will open the relay if the battery voltage gets too low Otherwise they are never used for anything and everything gets connected directly to the battery terminals.

Hello Mr Sunking, thank you for replying my thread.
so, in this case, i dont use the LOAD terminal , but the CHARGING terminal of CC. and it will go to the battery. then it will paralelly with big load such as DC motor controller.

so i just wanna make sure that the system design is working. how do you think about that? if i had big load, it will need a big current, in my calculation, the solar panel and battery should work together to power the load.

and for your information, i just use 1 battery

[Sunking]

So, what actually happend if i have system like this:
solar panel go to CC, the ouput CC for charge the battery going to battery, and then the battery parralel with big load (usually go to motor controller first) , like DC motor
so i dont use the LOAD output of the CC, but the CHARGING output of CC

what will happend if i design the system like that?
sorry for this question, im very very beginner in this. Thank you

You get nothing. The LOAD terminal on controllers are pretty much useless. The are for very low power gizmos like a LED light. It is just small relay with a fuse, and a LVD that will open the relay if the battery voltage gets too low Otherwise they are never used for anything and everything gets connected directly to the battery terminals.

[inetdog]

So, what actually happend if i have system like this:
solar panel go to CC, the ouput CC for charge the battery going to battery, and then the battery parralel with big load (usually go to motor controller first) , like DC motor
so i dont use the LOAD output of the CC, but the CHARGING output of CC

what will happend if i design the system like that?
sorry for this question, im very very beginner in this. Thank you

You never want to connect either the battery or a large load to the LOAD terminals of the CC.
At most you may want to drive a relay from the LOAD terminal to provide a last-ditch low voltage cutoff function. But the LV cutoff threshold of the typical LOAD output is often too low to do much in the way of battery protection by itself.

Your description above is exactly the right way to handle large loads with battery and CC. All that you have left out is that you must have fuses between battery and load and between battery and CC.