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Overkill Solar Pathfinder BMS?

I’m wondering if the company is even operating anymore? They were in Florida during a hurricane. I want to switch from JKBMS, but with zero communication, I’m starting to look elsewhere.
 
They've been quiet. Probably very busy trying to get the new BMS rolled out.
They told me they are still working on it.
They are supposed to e-mail me when it's ready to go.
Hope it's soon, my panels are up & inverters in place, just need to wire it all up.
We have (48) EVE 3.2v-280ah cells top balanced ready for the BMS.
 
Got three JBD 200A BMS's for 16S LiFePO4 packs, would buy one of these just because it will have decent documentation and somebody who knows it thoroughly fixing issues and answering questions. From what I've seen of OverKill they will probably do this right, but verifying that it communicates correctly with dozens of inverters and chargers is not a job I would choose to take on. Doing 175A continuous with no cooling fan is plenty, seems this could be pressed considerably higher. The high side switching is nice, simpler and less likely to have wired wrong with disastrous consequences. They state a primary reason to design their own is lack of Bluetooth security on JBD, but that could be easily solved with a new hardware Bluetooth plug in module that implements their favored encryption, and a phone app to communicate with it. Or even more secure, remove that Bluetooth module and use a wired connection which is an option right now for all of us. But sounds like a fun project and they can rationalize it however they wish.
 
I have been wanting to build two more 12v, 4S batteries but have been holding off, for quite a while, waiting for the new Overkill BMS. Sure hope it is ready soon … and that it actually works without bugs.

I have been running the Overkill 12v, 4S 120A BMS for over two years now and am not looking forward to switching brands.

I may have to start searching for another JBD BMS, as an alternative to the Overkill BMS, but hate to do so.
 
I have been wanting to build two more 12v, 4S batteries but have been holding off, for quite a while, waiting for the new Overkill BMS. Sure hope it is ready soon … and that it actually works without bugs.

I have been running the Overkill 12v, 4S 120A BMS for over two years now and am not looking forward to switching brands.

I may have to start searching for another JBD BMS, as an alternative to the Overkill BMS, but hate to do so.
Same here, been waiting a long time.
We have (48) EVE 3.2v - 280ah cells top balanced ready for the BMS.
Hope Overkill gets it done real soon!
 
High side switching will be nice, makes using direct wire connections to UART's on the BMS much safer. On JK and JBD BMS's with low side switching, when there is a fault the BMS cuts the connection from the battery to the load through the negative wire from load to battery. A miniscule current drawn from the load will cause the load's negative connection to rise up till it meets the battery's positive connection. The load in my case is the 120/240 VAC inverter that powers my house, so the house wiring safety ground is now at the same voltage as my 48 Volt battery's positive lead. My UART connection into the BMS is still referenced to the battery's ground side, so my computer plugged into the house wiring will see around -48 Volts DC on the GND, RX and TX pins at the "GPS" or Bluetooth connector where I get my UART connection into the BMS. This will at least blow my UART-to-USB adapter, and perhaps my computer.
 
High side switching will be nice, makes using direct wire connections to UART's on the BMS much safer. On JK and JBD BMS's with low side switching, when there is a fault the BMS cuts the connection from the battery to the load through the negative wire from load to battery. A miniscule current drawn from the load will cause the load's negative connection to rise up till it meets the battery's positive connection. The load in my case is the 120/240 VAC inverter that powers my house, so the house wiring safety ground is now at the same voltage as my 48 Volt battery's positive lead. My UART connection into the BMS is still referenced to the battery's ground side, so my computer plugged into the house wiring will see around -48 Volts DC on the GND, RX and TX pins at the "GPS" or Bluetooth connector where I get my UART connection into the BMS. This will at least blow my UART-to-USB adapter, and perhaps my computer.
I'm glad I read this, I was probably going to plug a JBD BMS into a nice server's USB port, but that sounds like a terrible idea and I should just use an RPi or ESP32 instead and not connect them to anything but power (ie use wifi and not ethernet). Would it also be a bad idea to have the JBD BMS grounded to my server rack? I currently have it screwed to the rack (not connected yet). The rack itself is basically grounded via the case of everything else mounted in it that plugs into the wall.
 
I'm glad I read this, I was probably going to plug a JBD BMS into a nice server's USB port, but that sounds like a terrible idea and I should just use an RPi or ESP32 instead and not connect them to anything but power (ie use wifi and not ethernet). Would it also be a bad idea to have the JBD BMS grounded to my server rack? I currently have it screwed to the rack (not connected yet). The rack itself is basically grounded via the case of everything else mounted in it that plugs into the wall.
I'm a retired electrical engineer and I find this all a bit confusing, especially given the poor documentation. If your BMS has a metal case it's probably ok to bolt it to a grounded server rack. I'd first disconnect the BMS completely, then check to verify that the battery minus lead from your BMS is not connected to the BMS case, using an ohmmeter. It would be ok if the negative lead going from the BMS to the load (perhaps an inverter) is connected to case ground, but my particular BMS seems to have no connection at all to its metal case.

Before answering your post, I probed around and found that the ground pin of the 4 pin GPS connector on my JK-B2A20S20P is connected to the big fat minus lead for BMS to the load, but not to the BMS's battery minus lead. So in this case my previous post may be overly cautious. However, here's a discussion (toward the bottom) about connecting to the 3.3v CMOS TX and RX UART lines of the "GPS" connector of a JK BMS, and they insist you should use an isolated UART to USB adapter, which is why I wrote that post: https://github.com/Louisvdw/dbus-serialbattery/discussions/250

Best bet probably is to hook my "GPS" 3.3v CMOS port up to an RPi somehow (either to UART GPIO pins, or through a UART-to-USB adapter cable), and then power the RPi off of an isolated wall wart. Or better yet, some sort of local battery that gets charged from the isolated wall wart so I can check up on BMS status when the lights go out.

When I checked the ground pin of the 3 pin CAN/RS485 connector, it was not connected to any of the other grounds, which may mean that unlike the "GPS" connector it is totally isolated internally on this particular BMS. But none of that is documented in the BMS manual, and near as I can tell very few people in the forums understand any of this.

Speaking of confusing documentation, the 4 pin "GPS" connector might have been used initially for UART connection to a real GPS for use in a moving vehicle, but it seems everybody uses that connector for an "RS485" connection using an external 3.3v CMOS UART to RS485 adapter supplied by BK. The CAN/RS485 connector is typically set up to use the CAN bus protocol for communications with an inverter and/or charger so they can be shut down nicely before the BMS shuts down the contactor if cell voltages get out of line. This CAN/RS485 connector is seldom set up as an "RS485" port to be used for user communication into the BMS (as an alternative to using Bluetooth or the "GPS" UART port). You can go in with a Bluetooth connection and configure the "GPS" and "CAN/RS485" connectors on this BMS for other than the default use case.

At least the above is what I think. Could be wrong, the more I probe the more I learn.

Looking forward to this new Pathfinder BMS, am hoping this will be all fully documented, and have a reasonably simple implementation. Easily worth an extra $100 in my book.
 
I'm a retired electrical engineer and I find this all a bit confusing, especially given the poor documentation. If your BMS has a metal case it's probably ok to bolt it to a grounded server rack. I'd first disconnect the BMS completely, then check to verify that the battery minus lead from your BMS is not connected to the BMS case, using an ohmmeter. It would be ok if the negative lead going from the BMS to the load (perhaps an inverter) is connected to case ground, but my particular BMS seems to have no connection at all to its metal case.

I checked and there is no conductivity between the BMS input/output cables and the case. There is conductivity between the input/output cables and the battery terminal leads. I also verified that there's conductivity between the BMS case and the rack and other items mounted in the rack.
 
I checked and there is no conductivity between the BMS input/output cables and the case. There is conductivity between the input/output cables and the battery terminal leads. I also verified that there's conductivity between the BMS case and the rack and other items mounted in the rack.
Makes sense there's no connection to the case. If the case is to be grounded it is best to tie to your system safety ground, same as the outlets in your house wiring. By "battery terminal leads" you mean the skinny sense leads out to all the cells? Yes, those will be high impedance to the heavy battery ground and load ground cables, as the sense leads are easily tied to the wrong cells and that would fry those sense wires and traces rather quickly it were a low impedance path. (The sense leads probably have series resistors of thousands of ohms.)

You wrote:
"I was probably going to plug a JBD BMS into a nice server's USB port."
I assume you were going to run a 3.3v UART-to-USB cable (an FTDI TTL-232R-3V3 or similar) from the Gnd, tx, and RX pins of the "GPS" port of your BMS to that server. That might work fine if the ground pin of your "GPS" port is 0 ohms to the cables that go from the BMS to the load (typically an inverter). Otherwise you need an isolated UART-to-USB adapter such as they discuss here: https://github.com/Louisvdw/dbus-serialbattery/discussions/250 On my JK BMS, the VCC pin of the GPS port is tied to the B+ wire of the sense cable, and so is at 48 volts, you probably don't want to use that. Also, know that you will be tying the TX pin of your UART-to-USB adapter to the RX pin of your BMS's GPS port, and the RX pin to the TX pin. I have not yet gotten my BMS to talk over that port yet, all I have is Bluetooth which is a pain because my cellphone is not suited to run a Bluetooth connection full time for years. Anyways, much better to tie that GPS port to a nice cheap and well isolated RPi.

To get this back on topic, the Pathfinder could clean up all this silly business of grounds that aren't always grounded, and ports that do stuff other than what the label says. If you want to persue your issue further, that should probably be a new thread, or perhaps you can send me a direct message.
 
A high side contactor on the Pathfinder seems mostly good.
But one consideration is protection from shorts on the battery.

There should be protection for dropping a grounded conductor into the battery
or onto the B+ cable. (Dropping a wire with B+ into the battery is much less likely)
On a BMS with a low side contactor, the overcurrent protection in the BMS
should offer this protection, assuming it works given the huge momentary current involved.

With high side protection, I'm thinking a big fuse between battery B- and the BMS B-
would be a good idea. Probably a good idea on a BMS with low side protection too.

My battery might be asked to supply up to 200 Amps to the inverter for a few seconds,
100 Amps continuous. A 200 to 400 Amp fuse should be about right for this.
The B- sense line should go directly from BMS to battery, but the fat B- cable
should go through that fuse from BMS to Battery.

Jerry
 
We wanted to wait until the new Pathfinder was ready to go but we need to get our battery banks up & running now.
I decided to try the JK-PB2A16S20P, it's 200amp with 2amp active balancer.
Bought 1 to try it out, if everything works as it should we will order 2 more.
They are a bit pricey but with the overall price of our complete system, what's a few more $$$.
 
I bought a JK B2A20S20P from the HankzorBMS Aliexpress store a year ago
to replace a JBD. It's been doing great.
200A, 2A active balancing, well packaged.
Hankzor has been recommended by others here on the forum.
They actually support this product through their contact page.
Currently $103.47, free shipping from a warehouse in the US.

Not sure how the PB2A16S20P would be different, I may need to look into that one.
It's 107.49 on the "JKBMS Oficial Store" with free shipping:

I'm happy with the B2A20S20P now that I've figured out the 3.3v UART port.
Bluetooth is a PITA for monitoring, I was forever re-establishing a connection with my android phone.
I haven't looked into current opinions on the B2A20S20P, perhaps it is no longer favored.

Could be that "JKBMS Oficial Store" is now the place to buy.
Or could be that it is not actually their official store, for all I know.
 
I just happened upon this thread and the pathfinder has grabbed my attention, but on there page there has been no updates since September. is there anyone in the know, who knows what's going on?
 
I just happened upon this thread and the pathfinder has grabbed my attention, but on there page there has been no updates since September. is there anyone in the know, who knows what's going on?
Why they don't update what's going on is beyond me.
I sent a private email to them & they did reply back.
They hope to have it ready in the 1st quarter of next year.
May be end of March or they could miss their expectations & be later, who knows.
We decide not to wait any longer & ordered a JK BMS, hope it works out.
 
Why they don't update what's going on is beyond me.
I sent a private email to them & they did reply back.
They hope to have it ready in the 1st quarter of next year.
May be end of March or they could miss their expectations & be later, who knows.
We decide not to wait any longer & ordered a JK BMS, hope it works out.

ya for me its not a question of "can wait" . I have 4 setups now with older JBD (3 years old I guess) and I like the setup on the pathfinder so I would consider upgrading when they are ready.
 
ya for me its not a question of "can wait" . I have 4 setups now with older JBD (3 years old I guess) and I like the setup on the pathfinder so I would consider upgrading when they are ready.
We have invested a lot in our new system & need to get it producing ASAP.
Our electric bill has gone through the roof, so we just can't wait any longer.
 
We have invested a lot in our new system & need to get it producing ASAP.
Our electric bill has gone through the roof, so we just can't wait any longer.
Get a JK now, and a Pathfinder once it's available and people say it works. You'll want a backup anyway.
 
Well I guess I'm gonna have to find another source for a BMS. Overkill seems to have just left us all hanging for months. I can wait no longer. I like the ones I have but feel somewhat abandoned now. I will look elsewhere like the others have done. They should have kept selling the old ones until they were ready to release the pathfinder and then faded out the old style. All they have done is lose customers.
 

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