I want to design a MPPT controller, but I want first to know how much power is needed. I have a 250W solar panel with V_open circuit is 37.7V. I have a 24V, 100A BLDC motor. I have also 80AH Cap battery. I will make the solar panel operate at max power and then charge the battery.


if this battery is fully charged, how much and long roughly can the motor run at max?

is there a good procedure to evaluate and record the ratings of the equipments and then start the design process?

 

80/100 = 0.8 hours = 48 mins. at full power. Less actually as there are losses to take into concideration.

A 100Amp BLDC will not run at 100Amps unless it is fully loaded.
What are you trying to do?
If you want a constant 100Amps to the load. you will need to increase your battery and solar panel quite a bit.

 

80/100 = 0.8 hours = 48 mins. at full power. Less actually as there are losses to take into concideration.

A 100Amp BLDC will not run at 100Amps unless it is fully loaded.
What are you trying to do?
If you want a constant 100Amps to the load. you will need to increase your battery and solar panel quite a bit.

Based on 80AH Cap battery, is there a way to approximate (roughly) the time the DC motor will run under different load and no load? The reason I ask this question is to see if I need to add additional batteries or not based on the time the motor can run.

Thank you for your earlier answer.

 

It cannot be determined as you don't know the current for different loads yet.
But when you do, it is easy enough to get a rough indication.
An 80 AH battery can supply 80 Amps for one hour, 10 amps for 8 hours, 5 amps for 16 hours.
It is just Amps x Hours = 80.
But 100Amps, as mentioned in your original post, is a pretty hefty current for a battery to supply.
For the suspected current I think you will need to increase your battery capacity quite a lot. And the solar panels.
What is your actual application? How long will it need to run and how important is it?
Solar power is not real good for very large power supplies without some backup if it is critical.
I have "10KW" solar panels here and usually the peek power is about 8KW on a bright day, but some days it only gets to about 300Watts.

 

80 Ah battery but @ what V ?

 

80 Ah battery but @ what V ?

24V

 

It cannot be determined as you don't know the current for different loads yet.
But when you do, it is easy enough to get a rough indication.
An 80 AH battery can supply 80 Amps for one hour, 10 amps for 8 hours, 5 amps for 16 hours.
It is just Amps x Hours = 80.
But 100Amps, as mentioned in your original post, is a pretty hefty current for a battery to supply.
For the suspected current I think you will need to increase your battery capacity quite a lot. And the solar panels.
What is your actual application? How long will it need to run and how important is it?
Solar power is not real good for very large power supplies without some backup if it is critical.
I have "10KW" solar panels here and usually the peek power is about 8KW on a bright day, but some days it only gets to about 300Watts.

I want it to move a small cart but couldn't estimate the current for different loads etc.

thank u for answers

 

Your motor is rated for 24V x 100A =2400W, but your panel puts out 250W max, so at least ~ 90% of the power for running the motor will be drawn from the battery. Assuming you don't want to kill the battery by running it completely flat, let's assume the realistic Ah capacity is ~ 80% of the 80Ah rating. At a load current of 100A the battery charge should then be good for 80Ah x 90% x 80% / 100A = 0.576 hours, i.e 35 minutes (if it doesn't overheat and boil off the electrolyte).

 

Out of thin air & a 24 V electric tractor, no load = 10A, medium load =20 A, med. load 6% grade = 40 A, start
80 A.

 

For better current vs power might try a Prony brake.

 

Out of thin air & a 24 V electric tractor, no load = 10A, medium load =20 A, med. load 6% grade = 40 A, start
80 A.

Thank you very much. I want to estimate the amp during no load, medium, or full load and the start. But could you please tell me how did you estimate that?

 

How do you know that it is a 100 amp motor?? Does it have a nameplate with specifications like volts, amps, RPM, and horsepower? And how is the electronics package labeled?A lot more information is needed to be able to offer any useful suggestions.

 

How do you know that it is a 100 amp motor?? Does it have a nameplate with specifications like volts, amps, RPM, and horsepower? And how is the electronics package labeled?A lot more information is needed to be able to offer any useful suggestions.

Thank you very much. I got them and they are as follow:
volts: 24-48V
Speed: 2150-4250 RPM
AMPS: 98A
Duty: cont
Torque: 80LB.IN(9N.m)
Power: 2000-4000W
it is PM DC motor

 

That is indeed quite a powerful motor. The starting current will be greater, that published 98 amps is the full load running current. So you will need a lot greater current capacity in your PWM controller. Is the electronic controller part of the motor assembly, or is it separated? For an electronicly commutated motor of that size I would expect some control functions to be provided in the electronic control package part of the system. That may save you a lot of effort if there are controls as part of the package.