MinispotA was $60 + $15 shipping. If you have a high C lipo, thatās all you need, otherwise a $45 lipo works. Thats, what, around the cost (or slightly below) of a low quality Sunnko from Amazon?
Even taking into account a full spot welder for your first build + materials/cellsā¦ The cost is around equivalent to buying from a reputable builder. Not to take business from them, not everyone has the time, attention to detail, or desire to build (or even buy) more than a single pack. In those cases Iād say buy- otherwise, equivalent cost with investment in time and research for the first and massive savings after that, totally a spot welder is worth it, I put it off too long.
This is a terrible idea. google it up. steel contacts are very high resistance. If you draw more than like 3 amps it heats up, bends, gets brittle, etcd. Contact gets worse, more heat, meltie meltie.
You say 20-30amp like itās nothing. That is quite a lot of energy.
Yeah thatās why I said google. Lots of people have tried and documented the fail. If you do a bypass mod, where you solder some copper where the cells contact, it has a chance. Might be worth a try in a charging station or a flashlight. Not worth the trouble at all in a vehicle.
Definitely a good point! That what I made wrong in my first build. 12awg for charge portā¦18awg would have just melted away. Better even using a 8-10a fuse as well on the charge port.
Just before i fire this thing up and charge it i wanated to make sure everything is ok so i dont get the magic smoke. i have a 7.5 A fuse wired for charging.
i was just charging my pack up and felt that the bms is pretty hot. Should i be concerned or is this normal. I think those are capictors. Not suremaby @thisguyhere or @b264 could help me.
it has been staying at around 95 degrees for 18min unplugged
So I have a real hard time trusting these cheap BMS. I used a stripboard pcb and some male headers to make a parallel board for the balance connectors, then hook up one of those bluetooth smart bms, to monitor cell voltages. I hook it up, then charge through the dumb bms, and can check whatās going on. Along with a FLIR to see where the heat is being made.
Lol I usually donāt like what I see, and it takes hours and hours, but it lets me understand the behavior.
this is why bms shouldnāt be attached directly to the battery.
can you share some pictures?
iām finding these small bms ineffective for large packs - i mean, balance current on the d140 (and most bms for that matter) is less than 0.01A - so at that rate to balance a, letās say 6p cell or 18Ah cell, thatāll take forever.
i have a 7.5 A fuse wired for charging.
10ch
i was just charging my pack up and felt that the bms is pretty hot. Should i be concerned or is this normal. I think those are capictors. Not sure
maby 