Now the Overload beta boards is finished, we will use this prototyping to verify our schematic design and test the actual effects.
The OverLoad will use the ATmega328P instead of using the C8051, and there will be arduino bootloader in chip, you can easily use the Arduino IDE to upgrade new firmware – the firmware code is open source, you can DIY the personalized UI yourself.
OverLoad not only a electronic dummy load but also the voltmeter and ammeter. On the prototyping board we use the 74HC4052 to switch different function channels. There is a rotary Encoder for menu selecting, and a rotary potentiometer for dummy load value adjusting.
A 10W 1R 1% power resistors will be used to replace now the 5W 1R 5% one, it will help improve the sampling accuracy. Indeed, even the 1% accuracy is not enough for a measuring instruments, but for a simple dummy load, we consider that this equipment can meet many simple requirement when you testing your power project.
For voltmeter and ammeter, we use the 12bit ADC for sampling. The Initial target we want to reach is: 0-30V range, 10mV accuracy; 0-3A range, 30mA accuracy.
Buzzer and Micro SD card slot are available in board. But will not be used in the 1st version firmware.
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You may have missed on the C8051 load upgrade page. Here are my comments from using the C8051 first version:
1. It was quite difficult to properly put the C8051 in a case, so maybe “enclosure” can be supplied as an option.
2. Have load available on banana socket shall be nice too.
3. I have a bench load tester in the lab. Due to the portability of C8051 loader, I am looking to use C8051 in the field, and for some quick and easy load testing. If it can be operated from an onboard battery, it shall be nice.
new 4. Have a load on/off toggle switch. Default off. This shall allow for setup(wiring and settings) to be done, check done, prior turning on the load.
new 5. if you have amp/volt monitoring built in. Shall be useful for it become a wattmeter and power analyzer:
new 6: likely to be a sw feature, if it is not included, arduino platform shall allow easy addition: a pulsing light loader to test battery. This shall allow a more accurate testing of batteries without eating up its capacity.
I want this! Please send email when ready and I’ll order immediately. Thanks for the 30V/3A upgrade, its perfect for our solar products testing.
http://iteadstudio.com/iforum/viewtopic.php?f=12&t=574
You can see the update here : )
@Ling SM:
Thanks for you kind feedback.
1. Yes, the C8051 code is so rough and we will improve this poor operating experience in this version.
2. You can see the banana socket there : )
3. This load can work with the 12V battery – also the C8051 one.
4. Load on/off switch will be added , thanks for the suggestion.
5. Yes, it can , the same hardware but the different code- everything is opensource.
6. We are going to make a smart battery charger, but will not in this one.
@ Craig Hollabaugh:
I am sorry that can not work with 30V3A… 90W load could not be so small… The spc for dummy load should be 12V-2A max, and the 30V and 3A is for the meters.