Recent content by bww129

Appreciate the links but the first two were posted after I purchased the pack. The third link is initially very positive about the cell with some people saying otherwise. Seems a bit early to say one way or the other, doesn't it? If the cells were really known to be so bad then why did Luna use...

Finally got back to working on this because it's difficult to be around for so long while each group charges, but I got to C6 and measured 2.45V on both C6 and C7. That doesn't make any sense when they were 3.5V and 3.8V before. The full stack voltage is 54.6V, which is higher than before, and...

Group C1 charged up from 3.79V to 3.96V. Group C13 charged up from 2.94V to 4.07V. Charging C4 now. Seems to be working so far but there's still a ways to go. Charging is done with a lab power supply set to 4.2V and a 1.5A current limit to CC/CV charge the groups. I'm afraid to push the current...

Did you ride with me every time I used the Wolf pack? Were you in my house every time I charged the pack? The battery, and typically my bike which is a daily rider and not a downhill racer BTW (since you apparently know all about me), was stored in my basement. I got the 30Q pack because Luna...

That's a great design that will ensure higher pack capacity over a longer period of time because the cells will almost always be balanced after a charge cycle. Unfortunately the Luna packs use a BMS that appears to only balance at a higher voltage, and the balance current is likely a bit too...

It's not pretty and not for the faint of heart, but if it can save the pack then it's worth it. Covering up these sections with some hot melt or other electronics grade silicone will still retain the waterproofing.

Hate away without any details... or read on for more information. The pack was purchased in March of 2020 and I've used it in the spring/summer/fall since 2020. A couple of times in the snow in 2020 too! The potting is a nice weather proof feature and works really well. Using the battery pack...

I first attempted to use a hot air gun to melt away the potting but it resulted in a fair amount of smoke and didn't melt it away as quickly as expected so I stopped before melting much away. The next attempt I owe to our local takeout place because I saw some plastic utensils and decided to try...

If the manual rebalancing doesn't work I'll probably try to take the entire ABS shell off to see if any of the cell level fuses have blown. Not sure what else to do with it... It's a shame the BMS does such a poor job of balancing the cells. I typically charged it to 100% too, which should have...

This pack was great for a couple years but has gone downhill fast. It now has very limited capacity and I had to find out why so I decided to cut into the housing and try to measure the cell voltages. After doing a bit of digging I found photos of the clear potted packs that show the location of...

Very admirable of you jumping straight into the deep end on a project like this! I would have recommended you take it a bit slower and read through all the threads of other builds to learn from what everyone else has done before going all in on a design, but that is a great way to learn. BTW...

Accurate CAN bit timing requires an accurate clock source once you get into the 500k-1M baud rate range. Reduce your baud rate to 250k if possible and that will help alleviate the issue. Don't underestimate the importance of the crystal, especially for CAN and USB. The tolerance of internal RC...

One thing to note about the ST CAN bootloader is that they specify the use of PB13 CAN2_TX pin 34 and PB5 CAN2_RX pin57 on the STM32F405 as the bootloader pins. This differs from PB8 CAN_RX pin 61 and PB9 CAN1_TX pin 62 used on the VESC. I'm not much of a software guy and don't know if those can...

Yes, they know it is open source and that code additions would be open source. Adding a CAN bootloader, while not trivial, would likely be based on the existing ST CAN bootloader which isn't proprietary. Changing the CAN messaging format to be more J1939 like is a different story. The open...

It never hurts to include support for it in your design. If you don't want to use CAN then just don't populate the CAN transceiver and supporting components. Unless you're really cramped for space there's not much downside. The company I work for has just become interested in a modular BLDC...