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KA2IRQ

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Apr 29, 2022
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Hi folks,

I'm a trustee for an amateur radio repeater system... basically two-way radio equipment that sits at a remote site. I'm researching replacing our old lead-acid batteries with LiFePo4, BMS, and charger.

Is there a BMS that allows some sort of remote Internet access? Or at least has a built in web page for control/monitor? The phone bluetooth apps are great if you're local at the site, but we need to be able to monitor the system and kill power to the repeater remotely. We are investigating Arduino and Raspberry Pi based custom systems, but we'd have to build in a lot of the functionality that already exists in the BMS. I hate re-inventing the wheel.

I understand the networking around it- we have that part of it under control. I just need a BMS that can do more than Bluetooth. WiFi would be OK, but a wired network connection would be better.

Thanks!
 
I just realized that the repo name has nothing to do with shoes.
 
Why do you need remote access to the BMS? These systems are designed to be set and forget. Not to interact with them constantly.

If this is for monitoring the voltage/SOC - are you going to act somehow if the SOC gets low?
 
brum said:
Why do you need remote access to the BMS? These systems are designed to be set and forget. Not to interact with them constantly.

If this is for monitoring the voltage/SOC - are you going to act somehow if the SOC gets low?
Click to expand...
A repeater is basically a transmitter, receiver, power supply, and Linux-based controller. We're having an issue where that controller gets buggy and needs to be rebooted- like once every 4 months or so. We've been working with the manufacturer to no avail. Problem is, if you remove AC power from the power supply (which is built-in to the unit), it just switches over to use its 12VDC backup battery. So to reboot remotely, we need to remove power from both the AC and DC ports. The BMS would easily allow us to do this by just turning off "discharge."

We are building a system to remotely remove AC power. We could add on a relay to remove DC power as well. However, I would also like to replace the SLA batteries and 1970's battery charger with a LiFePo4/BMS solution just because of the added capacity, reduced weight when it has to be moved occasionally (cleaning, etc.), and just, you know, it's better. So since LiFePo4 is the plan, I thought I would find a BMS that allows me to do this without having to build all the other control stuff, which will save us time, money, etc. Plug and play is better than re-inventing the wheel.
Also, since this is a remote site that we visit only once or twice per year, yes, if the SOC gets below a certain point, we will kick on a charger to top off the batteries. Would be a simple case of leaving the charger connected and disabling charge in the BMS until needed. Or maybe there's a better way- haven't thought of that yet. Unfortunately, no solar access to this site as we don't own the building and there's no place to mount panels.
 
KA2IRQ said:
A repeater is basically a transmitter, receiver, power supply, and Linux-based controller. We're having an issue where that controller gets buggy and needs to be rebooted- like once every 4 months or so. We've been working with the manufacturer to no avail. Problem is, if you remove AC power from the power supply (which is built-in to the unit), it just switches over to use its 12VDC backup battery. So to reboot remotely, we need to remove power from both the AC and DC ports. The BMS would easily allow us to do this by just turning off "discharge."

We are building a system to remotely remove AC power. We could add on a relay to remove DC power as well. However, I would also like to replace the SLA batteries and 1970's battery charger with a LiFePo4/BMS solution just because of the added capacity, reduced weight when it has to be moved occasionally (cleaning, etc.), and just, you know, it's better. So since LiFePo4 is the plan, I thought I would find a BMS that allows me to do this without having to build all the other control stuff, which will save us time, money, etc. Plug and play is better than re-inventing the wheel.
Also, since this is a remote site that we visit only once or twice per year, yes, if the SOC gets below a certain point, we will kick on a charger to top off the batteries. Would be a simple case of leaving the charger connected and disabling charge in the BMS until needed. Or maybe there's a better way- haven't thought of that yet. Unfortunately, no solar access to this site as we don't own the building and there's no place to mount panels.
Click to expand...
I use a seplos BMS and tunnel the RS485 comms connection over TCP/IP to any location in the world. as long as you have an active internet connection at the repeater side you can access the BMS. All freeware tools too ser2net on Linux or COM2TCP on windows. simple as two R-pi zeros or similar, ser2net on both and a tunneling app like tailscale. this sould work for any BMS that uses any kind of serial comms
 
KA2IRQ said:
A repeater is basically a transmitter, receiver, power supply, and Linux-based controller. We're having an issue where that controller gets buggy and needs to be rebooted- like once every 4 months or so. We've been working with the manufacturer to no avail. Problem is, if you remove AC power from the power supply (which is built-in to the unit), it just switches over to use its 12VDC backup battery. So to reboot remotely, we need to remove power from both the AC and DC ports. The BMS would easily allow us to do this by just turning off "discharge."

We are building a system to remotely remove AC power. We could add on a relay to remove DC power as well. However, I would also like to replace the SLA batteries and 1970's battery charger with a LiFePo4/BMS solution just because of the added capacity, reduced weight when it has to be moved occasionally (cleaning, etc.), and just, you know, it's better. So since LiFePo4 is the plan, I thought I would find a BMS that allows me to do this without having to build all the other control stuff, which will save us time, money, etc. Plug and play is better than re-inventing the wheel.
Also, since this is a remote site that we visit only once or twice per year, yes, if the SOC gets below a certain point, we will kick on a charger to top off the batteries. Would be a simple case of leaving the charger connected and disabling charge in the BMS until needed. Or maybe there's a better way- haven't thought of that yet. Unfortunately, no solar access to this site as we don't own the building and there's no place to mount panels.
Click to expand...
Sounds like a job for a heartbeat/keepalive system.
 
As @shavermcspud suggested above... if you need the whole BMS output relayed. There are also commercial RS485 to TCP/IP devices out there like one from Waveshare which only costs about 20 GBP (UK price).

But, if you only need to remotely turn charge / discharge off, then, similar to the github link above, there is also the overkill/JBD BMS, which has an Arduino compatible API that can be run on an ESP32 or similar - see...

github.com

GitHub - FurTrader/Overkill-Solar-BMS_2-Arduino-Library: Read and Write Library for Overkill Solar BMSs

Read and Write Library for Overkill Solar BMSs. Contribute to FurTrader/Overkill-Solar-BMS_2-Arduino-Library development by creating an account on GitHub.
github.com github.com
 
KA2IRQ said:
We're having an issue where that controller gets buggy and needs to be rebooted- like once every 4 months or so.
Click to expand...
This sure smacks of a memory leak to me. Probably a good idea for them to audit their use of memory; primarily use of malloc and stack variables (locals).
 
KA2IRQ said:
So to reboot remotely, we need to remove power from both the AC and DC ports. The BMS would easily allow us to do this by just turning off "discharge."
Click to expand...

It is unlikely that you'll find BMS with WiFi capabilities. So you'll have to go with a custom solution that communicates with the BMS. This is overkill for a simple task. Get an ESP8266 and use relays to turn on/off the AC/DC power.

If you go with BMS communication, you'll have a much more expensive solution. Not only in terms of cost, but in terms of reliability.
 
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