Heltec (JK) 200A Smart BMS with 2A Active Balance

[lonertic]

No I'm using the full BMS with the additional 2a active balancer function built in.

Yup so that's the same as what I've got. I've got the 24S bms, 200A current with active balancer (2A) .... I wish the 2A was higher though. Jikong was willing to customise it with a higher current balancer for me but MOQ was like 100 units and I'm not made of gold... so...

if the 2Amp balancer in my BMS does not do the trick, I will be adding the additional 5 amps in parallel.

That's the part I'm not sure about... I actually don't know if it's possible to add an extra "active balancer" on top of the BMS with built-in balancer, like, what would happen if they get in the way of each other? have you or others tried that setup and know that it works? sorry im still new to this forum so that might've been covered in other posts.

Heltec seems to make some decent stuff.

Someone smarter than I could probably confirm/deny this.. but Heltecs appear to be just rebranded Jikong's, their company profile on alibaba suggests they're just a reseller/distributor judging by their employee count.. and Jikong's profile/website suggests they're a subsidiary of E&J Power which has thousands more employees, which is why the android bluetooth app is called "enjpower BMS", or a rebranded version called "jikong BMS" and if you open the APK file it's got enjpower files all over it...

 

[UV-PWRD]

Yup so that's the same as what I've got. I've got the 24S bms, 200A current with active balancer (2A) .... I wish the 2A was higher though. Jikong was willing to customise it with a higher current balancer for me but MOQ was like 100 units and I'm not made of gold... so...



That's the part I'm not sure about... I actually don't know if it's possible to add an extra "active balancer" on top of the BMS with built-in balancer, like, what would happen if they get in the way of each other? have you or others tried that setup and know that it works? sorry im still new to this forum so that might've been covered in other posts.


Someone smarter than I could probably confirm/deny this.. but Heltecs appear to be just rebranded Jikong's, their company profile on alibaba suggests they're just a reseller/distributor judging by their employee count.. and Jikong's profile/website suggests they're a subsidiary of E&J Power which has thousands more employees, which is why the android bluetooth app is called "enjpower BMS", or a rebranded version called "jikong BMS" and if you open the APK file it's got enjpower files all over it...

2a seems enough for me, but my pack was top balanced in parallel for almost 2wks prior to commission.

I thought I had balance issue but it turned out to be a bad washer on the balance lead. I redid them all and its been solid for the few weeks since, but given its autumn the pack is going between 80 and 20% mostly so I'm not getting into the knees where it's more obvious if there's an issue.

 

[Sanwizard]

No I'm using the full BMS with the additional 2a active balancer function built in.

I think I said DanF is using the balancer. I like you are using the full BMS with 2amp active balance function

 

[UV-PWRD]

I'm so confused, I am actually DanF IRL so I assumed you meant me as I didn't see a DanF here?

 

[Sanwizard]

I'm so confused, I am actually DanF IRL so I assumed you meant me as I didn't see a DanF here?

No worries mate. DanF is yet another Solar enthusiast, who also has a youtube channel I watch, along with Andy from off grid garage, and DMI inc. DanF and DMI also use MPP Solar LV6548 Inverters like I do. I learn from everyone I can!

 

[UV-PWRD]

My BMS has stopped allowing me to connect via Bluetooth, on 3 separate devices (iOS and Android).

Is there a way to reset/reboot without disconnecting from the inverter so I can avoid the pre charging caps process?

Can I just remove the balance lead harnesses and reconnect them?

 

[Sanwizard]

My BMS has stopped allowing me to connect via Bluetooth, on 3 separate devices (iOS and Android).

Is there a way to reset/reboot without disconnecting from the inverter so I can avoid the pre charging caps process?

Can I just remove the balance lead harnesses and reconnect them?

Just use a resister and reboot. I built one into my box with a momentary contact switch for maintenance.

 

[UV-PWRD]

Just use a resister and reboot. I built one into my box with a momentary contact switch for maintenance.

Can you snap a pic?
I never work with resistors so I'm picturing the little thin wire ones from high school, I can't see how I'd neatly permanently wire that in, but I know there'll be something more suitable.

 

[Sanwizard]

Can you snap a pic?
I never work with resistors so I'm picturing the little thin wire ones from high school, I can't see how I'd neatly permanently wire that in, but I know there'll be something more suitable.

You can use a ceramic resistor like the one shown, and toxh one side to your battery terminal and the other to the inverter. BMS would not need it, as there are no large capacitors like in the inverter.

I included a circuit on my battery box with the resistor across the switch connections, and a momentary switch to press before turning the switch itself to the on position.

 

[UV-PWRD]

You can use a ceramic resistor like the one shown, and toxh one side to your battery terminal and the other to the inverter. BMS would not need it, as there are no large capacitors like in the inverter.

I included a circuit on my battery box with the resistor across the switch connections, and a momentary switch to press before turning the switch itself to the on position.

This is my issue, I do not have an on/off switch (other than the battery to inverter breaker). As the BMS sees an inverter starting as a short, currently I connect a DC power supply to the battery main positive and the BMS output lead/inverter connection point and feed it a few volts above pack voltage and let it draw a couple amps until the inverter registers a battery, then I know the caps are charged and I can just remove the supply.

I guess I can wire direct from battery main neg to the other side of the battery breaker where the inverter can see it.

A part of this question also is knowing exactly what to disconnect to reboot the BMS, as I assumed it was taking it's running power from the 2 balance lead harnesses, which means I could just remove those and reconnect to reboot it or is it taking its running power via the main batt pos/neg wires?

 

[GXMnow]

An incandescent light bulb makes a good cheap power resistor for pre charging the inverter capacitors. Don't use LED of CFL. IF the inverter has very large caps, a 40 watt 120 volt bulb might even glow for a bit as it charges the caps up on a 48 volt system. You can connect the bulb or other resistor across your breaker. Once the voltage at the inverter is within just a few volts of the battery, you can then safely turn the breaker on with no surge. My Schneider XW-Pro actually powers up on the resistor, so I know it is charged and I can turn on my disconnect switch without a surge.

I do like the idea of the pre charge push button. I may add one to my system.

 

[Boondock Saint]

And how often does one need to do this inverter pre-charge? What are the circumstances that cause one to have to do it, or repeatedly have to do it? I'm not going to the back of my rig and pushing a button with any frequency, if it comes to that we need automation.

 

[lonertic]

My BMS has stopped allowing me to connect via Bluetooth, on 3 separate devices (iOS and Android).

hmm this is something i need to consider actually.. there is an advanced parameter for power-off voltage. I would assume one of your cells hit that limit and the BMS shut down to protect the cells (otherwise the BMS itself becomes a parasitic drain).. It's a good protection feature but I've never hit that limit (yet) and I don't have a reset switch either. My cells are placed on a metal shelf one on top of another, so if this happens to the bottom bank, I'll need to move half a tonne of cells above it just to get to it... Thx @Sanwizard for the resistor trick! I'll try that... do u have a quick wiring diagram of which end of the BMS to connect that to and which battery terminal? thx

 

[UV-PWRD]

I would assume one of your cells hit that limit and the BMS shut down to protect the cells (otherwise the BMS itself becomes a parasitic drain).. It's a good protection feature but I've never hit that limit (yet) and I don't have a reset switch either. My cells are placed on a metal shelf one on top of another, so if this happens to the bottom bank, I'll need to move half a tonne of cells above it just to get to it... Thx @Sanwizard for the resistor trick! I'll try that... do u have a quick wiring diagram of which end of the BMS to connect that to and which battery terminal? thx

Nah, the BMS is still running, charging and discharging as it should be it's literally only the bluetooth interface that doesn't work, it's been running for a few months already.

I have hit over and under voltage protection and I have my recover times configured accordingly, so I know what the behaviour from the BMS and inverter is in those instances.

I really think it's just the Bluetooth that has shit itself, could even be a hardware issue yet but I need to reboot it to start the troubleshooting process.

 

[Sanwizard]

hmm this is something i need to consider actually.. there is an advanced parameter for power-off voltage. I would assume one of your cells hit that limit and the BMS shut down to protect the cells (otherwise the BMS itself becomes a parasitic drain).. It's a good protection feature but I've never hit that limit (yet) and I don't have a reset switch either. My cells are placed on a metal shelf one on top of another, so if this happens to the bottom bank, I'll need to move half a tonne of cells above it just to get to it... Thx @Sanwizard for the resistor trick! I'll try that... do u have a quick wiring diagram of which end of the BMS to connect that to and which battery terminal? thx

I put mine on the positive side, but either side should work. Your battery on/off switch should be in series on your positive wire to the inverter from the battery. The resister goes across the switch connections in parallel, with q momentary switch in series on that wire.

So no resistance unless you hold in the precharge switch, let your capa charge, then let go of the momentary switch and turn on the main battery switch.

Will has a vid on pre-charge, and I borrowed the button idea from a russian dude on youtube.

 

[GXMnow]

If everything is working fine, you only need to deal with pre charging the inverter on the initial turn on. Mine was up and running 4 months before I had to do it again when a balancer lead failed. So I just used a clip lead and resistor again. It has been back up running over 3 months again without another reason to shut it down. So it is not like you nee to reboot all the time, and using a resistor and a clip lead does work just fine once in a while. But if I need to work on my system again, which I am sure will happen at some point, I might as well just wire it in so it is convenient to fire it up again. I may also wire in a second switch to jump start the BMS with a clip for a 9 volt battery. One time when I was using a clip lead, I dropped the end and it of course had to swing past one of the buss bars. It made a bright flash and burned 1/4 inch off the end of the clip lead with some flying molten metal. So having it nicely wired in with a button is definitely much safer. I have not dropped a clip lead again, seeing that once was more than enough. The current to fry that lead was nothing to this battery bank. The C rating on my cells puts my constant current capability at over 1,000 amps!

 

[Boondock Saint]

Right on, thanks! If I have to do something more than once, I want to automate it. The only think I do more than once is get up to pee and I'm working on that too.

It would be handy to accomplish the two things you mention with a touch of the phone through one of the apps.

 

[UV-PWRD]

Yesterday when I got home, the Bluetooth was now working correctly across all my devices by itself, and the BMS has continued to charge/discharge fine the whole time 0_0

Logs showed no issues at all since the last boot.

 

[lonertic]

I tried the switch method (but just by using a jump lead with the resistor). Didn't seem to wake up the inverter. As in, it did nothing.

The only time it wakes up is as per the manual, 5V+ to the B- (blue cable) side, and 5V- to the P- side. Well in my case i had a spare 12V battery to do it. I've completely rewired all my banks today. Holy cow it took some effort. But at least now each of the B- sides are easily accessible at a corner, and the P- side is the -'ve that goes to the inverter so it's always accessible. So that means if i ever need to wake it up i won't have to move all that weight again.

 

[Boondock Saint]

We could build in jumpers with 4' leads in order to conveniently supply that occasional 6v or 9v source. A 9v battery or pack of 4 AAA with a switch could sit there and be available and viable for many months of not years since the batteries will have no load on them.

Then all we have to do is push the switch on for a second and off again. It could be a momentary contact switch or mini switch w LED, so many options.