How about a low temperature shutdown for charging (at least as an option) - do not allow the charger to activate when temp is below 32F.
Having the charger on at a low current at that low temperature could actually keep the batteries from freezing.How about a low temperature shutdown for charging (at least as an option) - do not allow the charger to activate when temp is below 32F.
Yeah, I have taken a peak inside; it looks excellent. Have been thinking about buying it.Siwastaja,
Have you taken a peak at this:
Click on "search inside book" on the left under the picture of the book. Some great info. Goes over all the different designs. Sitting on my shelf if you want me to look anything up for ya.
Maybe, at least until they are full at which point you cannot charge anymore.Having the charger on at a low current at that low temperature could actually keep the batteries from freezing.
I highly recommend it. Basically reconfirmed everything I learned when I helped build/design some different BMS devices for a local Portland company.Yeah, I have taken a peak inside; it looks excellent. Have been thinking about buying it.
Yes, but if it's that cold, you know that it's cold well before and you can shut off the charger/turn it back on/turn off/turn on in anticipation. Eventually, you're right, but I don't think low temp should stop charging, it should continue it as long as it can.Maybe, at least until they are full at which point you cannot charge anymore.
No I don't have a better solution, and I consider this problem to be intractable when real-world economics are factored in. That is to say, it can't be solved without costing more money than consumers are willing to pay.Tesseract - is that not a problem with pretty much any of the commonly used BMS?
Do you have a better solution?
Nope. The PTC resistor has to be rated for the full pack voltage.I guess you could use small PTC heater elements instead of the shunt resistors.... i
You shouldn't need to bypass much current. I have seen no need to bypass more than 1/2 amp (EVpower regs) with a pre-balanced pack. I was eying a 2 amp fuse for about a 1.5 amp shunt.BTW, the fuse you suggest is only rated up to 5 amps, and costs about $3, which is more than the 30A relay I mention:
The Cooper Bussmann BK-PCx series fuses are a pretty good choice here, with the caveat that low amperage fuses tend to fail early from vibration/fatigue in automotive applications.... Here is an idea for the fuse....