Looks like two pairs of MOSFETs in a back to back common-drain configuration with the battery to charger ground direction bypassed by a 10k resistor and diode. The diode path is probably meant to tie their sources together so all 4 gates can be driven on the charger side.
It’s a really shitty lowside loadswitch probably meant to protect the pack from overvoltage or undervoltage on the charge port. Probably also doubles as an antispark on the charge port.
I can only guess the transistors you see there are a rudimentary comparator circuit.
I don’t know if there are components on the other side.
This part exploded instantly on my friend’s Hurricane as well. The guy has the worst luck with crappy premades.
Luckily I finally finished my second board so he’d have something to ride for a couple months while the replacement comes in.
It’s working again now but I got my fingers crossed. He bought the board second hand so next time this happens he’ll have to go through the original owner for warranty service again if it’s even still under warranty.
Every time someone in my group gets excited about the new hadean/hammer/hurricane/hambone/whatever I gently say hey guys maybe instead of throwing yet another premade on the ever growing pile of unfixable unupgradable trash that the makers have closed the revenue books on you should consider…
…no yeah that’s for nerds like me. Normal people buy premades.
If anyone is willing to part with their functional or fried module you can send it to me and I’ll take a hard look at its design. Maybe we have some relatively inexpensive options for replacement.
@frame to the rescue! He is sending a functional one to me.
It is a pretty good board and Meepo does pick up the phone unlike Lycaon and Team Gee which are the other dead boards the guy I was talking about has in a pile in his storage room.
I’m probably late to the party but still… I believe this has nothing to do with the anti-spark module (or whatever that thing is). That’s probably just due to the nature of how the li-ion chargers work.
The voltage that you measured on your charger output while disconnected (50.3V) is what it will use in the final phase of charging when the battery pack is almost fully charged. At that point the charger enters the constant voltage (CV) mode. However, in the early stage of charging, when the battery pack voltage is low, the charging is done in the constant current (CC) mode. This means that the charger decreases its output voltage to keep the charging current constant. The charging current depends on the difference between the battery pack voltage and the charger voltage. More difference => more current. As the battery pack gains charge, its voltage increases and thus the charger needs to keep increasing its output voltage to keep current flow constant… until it eventually reaches its max output voltage, at which point the CV phase starts.
It’s like if you’re trying to pull a spring at a certain constant pace (say 1cm per second). Initially, there’s very little resistance so you only want to apply little force, otherwise it would stretch too fast. As the spring stretches, you need to gradually apply more and more force to keep the pace constant. Eventually you reach your max force and the pace of stretching starts slowing down until it stops completely. Then the spring is fully charged.
That said, it’s perfectly normal that you measured 49V on the charger output after connecting it to the battery.
No time to start any testing yet but I wanted to post photos of the module @frame sent me. Seems they only had one length of heat shrink available. To be fair though it does provide double the thickness of protection for most of the board.
PNP and NPN transistors with lots of diodes and odd-valued resistors leads me to the same conclusions as @Gamer43, comparators for under- or over-voltage protection.
I don’t know if it provides any anti-spark function but if it does it uses a slow turn-on of the FETs to slow the inrush of current. It does not have a power resistor to do that job via a secondary channel for the current.
The third (red) connector pin/wire just provides power to the module so if using just a standard 2-wire charger the board will not power up and you will be prevented from charging.
Wow that’s even simpler than an analog enable pin, though I guess it’s following the same sort of philosophy as crappy home security systems: just make it the tiniest bit more complicated, if you’ve got the skills to deal with that you’ll probably know better than to bother
Ayo, so, did your battery implode in time because of this? I legit bought a second hand hurricane to upgrade with a DV4s because my budget boy doesn’t have enough juice to satisfy me anymore and THE LITERAL FIRST TIME I PUT IT TO CHARGE, the board stops charging on its own after a pop sound. I am at this point quite confident that it is this board because it also smelled quite foul. Wondering what the best way to buypass it is.
a. solder the wire directly
b. put a 7a fuse on the wire and still have it connect directly
c. try to contact meepo for a replacement or a discount on a replacement
Another thing I also noticed is the very aggressive sparking from the connections. Wouldn’t this be solved if I plug the charger in the board, then into a socket with an on/off button and then just turn the socket from off to on? Wouldn’t that prevent the sparks?
To be fair though it does provide double the thickness of protection for most of the board.
can’t stop me there