Charging System of Solar Car

[devonsc]

Hi, would like to have one simple question regarding the charging system of the solar car.

Mainly, the solar panel would be implemented for charging of the lead acid battery, is this right? Does it mean that the battery used to run the solar car will at the same time being charged while it is being used to supply the motor power?

 

[devonsc]

I'm actually building this battery charger unit to be fitted in the "middle" of the connection between the solar panel and the motor. I've been trying to read up certain website regarding Maximum Power Point Tracker but it seems that I couldn’t come into conclusion regarding the major differences between a MPPT and a normal battery charger.

Do you mind to briefly explain the difference between the MPPT and the battery charger? Am I right to say that, one of the major differences would be the ability for the MPPT to track and make certain adjustments to deliver a maximum power to the battery?

However, I'm building this battery charger unit, where I will boost the voltage level of the solar panel to an appropriate level for charging of the battery. This statement: "I will control the duty ratio of DC/DC converter to boost up the output voltage of the solar panel to an APPROPRIATE LEVEL". So, can I consider my battery charger a MPPT? However, I will not be able to deliver a maximum power to the load most of the time. In my situation, as a battery charger, I thought my main concern would be stepping the voltage level up to an appropriate level for charging to occur? Thus, how do I maintain or control to obtain a maximum power point from my charger?

By the way, I don't understand how do we connect the battery-motor-solar panel together. As in, if I simply connect them in series, does it mean that the output from the solar panel will first flow into the battery. But, if I turn the motor on, the motor will first "automatically" or "smartly" draw the current from the solar panel. If it is insufficient, then the remaining will come from the battery. Meaning, the possibility of having the motor undergo a charging process is impossible when I turn the motor on? Am I right to say this?

Thanks in advance.

 

[Klaus]

I wont try to answer all your questions :wink:
but, IMO, it is wasteful to "boost" the voltage from a solar panel in order to charge a battery.
Would it not be much simpler to string sufficient solar cells in series (~36) to make up a 'solar panel' with sufficient output voltage to charge a 12V lead acid battery?
The charge current you get from this depends on the wattage rating of the panel, the amount of sunshine and the solar cell type.

For your car, start with a fully charged battery. Connect the motor to the battery and the panel to the battery.
For long periods of non driving you'll need a solar regulator between panel and battery.
For car speed control you need a controller between motor and battery.
Some controllers can capture regenerating power during braking and feed it to the battery.

Wether you run out of battery charge or not depends on the operating conditions.
have fun

 

[devonsc]

Oh no...Klaus? Really need your opinion here. So, I should change my objective of my project then?

I guess I will have to reconsider my project all over again. Will get back to my post here later...

Thanks a lot, Klaus! Thanks a lot...