Forum Posts

• February 1, 2022 11:41 AM CET

  in the topic Max current rating in the forum Support

  Tamás Fábián said: Hello Ray, the absolute maximum value is 11.8 Volts. This comes from the datasheet of the integrated circuit we use for driving the outputs (DRV8833). The safe operating limit is 10.8 for the same IC. Having said that, we managed to overvolt SBricks up to 14 volts and never damaged a single one. However, do not take this as a recommendation. It's a bit like overclocking / overvolting CPUs and memory modules in a PC. Be aware that overvolting your SBrick beyond the absolute maximum voids your warranty. What you can do is: Play safe, and don't run the SBrick over 10.8V Accept some extra heating and reduced safety margin, and go near the absolute maximum limit of 11.8V Accept the chance of immediately and permanently damage or severely reduce the lifespan of your SBrick, and run it over the absolute maximum of 11.8V. Use a 3-cell Lithium Iron Phospate (LiFePo4) battery. With a maximum cell voltage of 3.65V it just barely goes over the recommended operating limit of 10.8V, and stays well below the absolute maximum. Ray Simon said: Thanks Lenard! I have a follow up question: Is it safe to connect a fully charged three-cell LiPo directly to the SBRICK Plus? I'm sure when the battery levels off to nominal voltage of 11.1V it is safe. The question is if the initial voltage of 12.6V will harm the SBRICK. I would like to use my hobby-grade 3S LiPo batteries with the SBRICK Plus. These are standard three-cell LiPo used for RC cars, airplanes, helicopters, etc. The behavior of these batteries is that at full charge, the voltage is 12.6V without load. After load is applied and some current draw, the voltage drops and levels off to "operating" or "nominal" voltage which is 11.1V. I have been researching other options to use my 3S LiPo batteries and you can get a DC-to-DC mini voltage regulator, but generally the output must be at least 1.5V below the input voltage, which means it would need to be set to about 9V to be safe to handle the LiPo as the voltage drops while it is discharged. This is possible but requires more complexity and equipment. It would be much simpler if we can connect the LiPo directly to the SBRICK. Thanks for your support!   A simple solution for using the ubiquitous 3C LiPo batteries is to wire one (or better two) standard silicon diodes in series with the sBrick. Each one will drop between 0.5V and 1V, depending on load conditions. At the same time, they will protect your sBrick from accidental voltage reversals. I am cuurently using one 1N5406. It is rated at 3A, which is good enough for my creations, and gives me an idle voltage of 12.0V at the input of the sBrick. Take another one to be on the save side (i.e. within specs).   Nikolaus
• October 5, 2017 5:29 PM CEST

  in the topic ipad2 iOS9.3.5 - no Bluetooth support? in the forum Support

  I have tested my iPad again, and Bluetooth appears to be working - it still interfaces okay with my EV3, the only other Bluetooth peripheral I have. What else can I try? Nikolaus
• September 22, 2017 9:04 PM CEST

  in the topic ipad2 iOS9.3.5 - no Bluetooth support? in the forum Support

  I am using sbricks for a while now and I am generally satisfied, but I wonder why my iPad2 will never connect to an sbrick. I normally use my iPhone 4, which works fine. The iPad always tells me to "activate bluetooth", even when it is already active. I tried to reinstall the app, no use. I tried to discover the sbricks on the OS settings, but they don't show up. My bluetooth works, at least with my EV3 brick. Restarting the iPad makes no difference, either. The two sbricks in my current model are stated to be "hardware 5, firmware 18". What can I do to make it work? LG, Nikolaus