REC ACTIVE BMS vs Orion Jr for 4S4P 280Ah LiFePO4 system

jmole

Solar Enthusiast
Hi all - I'm trying to decide on a BMS for my sprinter van battery system.

I'm looking at the REC ACTIVE BMS and the Orion Jr.

I like that the REC is already set up for 4S, and seems like it has the ability to work with the WS500 regulator I'm using, as well as Victron equipment.

But the Orion seems like it is better engineered with better documentation. The big con with the Orion, of course, is that you're limited to 150mA of passive balancing current. They claim that this isn't a big deal, but I do wonder about it. I will have 4 very high capacity cells in series; the cells are matched, but they still will need to be kept in balance, and I worry that 150mA just isn't enough to cut it for 1120Ah.

The big feature that I'd like is the ability to tell the WS500 and the Victron Multiplus II and the solar panel controller to stop charging, without needing to close a contactor to accomplish it. It seems like I should be able to do this with both systems.

Would love to hear from anyone who has experience with either BMS, and what they like and don't like about it.
 

jmole

Solar Enthusiast
I got this response from Orion:

A 4P configuration with 280Ahr cells (>1000 Ahr total) would be pushing it for what we'd recommend in a single JR unit as far as balancing goes. Depending on what type of cells being used that may still be achievable, but lower quality LFP cells would probably require more balancing than that arrangement would afford. Still, this would be the most cost effective solution though, and there are ways to better optimize the balancing strategy depending on how frequently you have the opportunity to balance.

You could consider a 24 cell Orion 2 standard BMS which has greater balancing power, though this may be somewhat overkill for your specific needs here.

I'm still leaning towards the Orion, since I'm using matched cells, but it does give me pause.
 

HRTKD

Boondocker
But the Orion seems like it is better engineered with better documentation. The big con with the Orion, of course, is that you're limited to 150mA of passive balancing current. They claim that this isn't a big deal, but I do wonder about it. I will have 4 very high capacity cells in series; the cells are matched, but they still will need to be kept in balance, and I worry that 150mA just isn't enough to cut it for 1120Ah.

The big feature that I'd like is the ability to tell the WS500 and the Victron Multiplus II and the solar panel controller to stop charging, without needing to close a contactor to accomplish it. It seems like I should be able to do this with both systems.

I don't know what the balancing power is on my Overkill Solar 4s BMS, but it's working great on my EVE 280Ah cells.

If you have the BMS telling the solar charge controller to stop charging, if there is a load on the system that the PV output could normally handle without dipping into the battery, how would that work? So far, I don't see a need for the BMS to communicate, but my system is small with only two 4s batteries for 560Ah.
 

Ampster

Renewable Energy Hobbyist
I have been using Orion BMSs for the past six years. A year ago when I moved to a larger LFP pack I was having some issues at the top with larger cell deltas. I thought about an active balancer but never implemented it. It has taken time but when the cells are at the end of contant voltage charging they are within 0.04 volts. It reduces as they are discharging to 0.005 volts. One of the favorite things I like about the Orion is the Orion Connect which allows me to see various stats and trends remotely.
 

jwelter99

Solar Addict
Hi all - I'm trying to decide on a BMS for my sprinter van battery system.

I'm looking at the REC ACTIVE BMS and the Orion Jr.

I like that the REC is already set up for 4S, and seems like it has the ability to work with the WS500 regulator I'm using, as well as Victron equipment.

But the Orion seems like it is better engineered with better documentation. The big con with the Orion, of course, is that you're limited to 150mA of passive balancing current. They claim that this isn't a big deal, but I do wonder about it. I will have 4 very high capacity cells in series; the cells are matched, but they still will need to be kept in balance, and I worry that 150mA just isn't enough to cut it for 1120Ah.

The big feature that I'd like is the ability to tell the WS500 and the Victron Multiplus II and the solar panel controller to stop charging, without needing to close a contactor to accomplish it. It seems like I should be able to do this with both systems.

Would love to hear from anyone who has experience with either BMS, and what they like and don't like about it.

Several systems using the REC Active and zero issues. Anywhere from 200Ah to 1120Ah of capacity.

In most of the cases they use the REC contactor pre-charge module along with a BlueSea RBS-ML 500A contactor. We have the first install next week with the new WiFi management module which looks really interesting.

All of them are integrated into Victron systems and the canbus works well. With a Cerbo GX with the separate battery BMS bus it works really nicely out of the box; and you have the ve.can free for solar charge controllers and such. Victron also has a forum for REC BMS which is a plus; not official support but pretty close.

Several systems use wakespeed WS500 regulators like you plan; but Balmar is also very popular and a traditional choice.

Support is top notch - 24 hour or faster response time via email. And the support is engineering grade who knows the product inside out and not some front line support.

I personally use a Batrium but must say if needing to do it all over would go REC as it just works with zero fuss. For a hobbyist it's a bit boring of a product as not much to tinker with; but for people just wanting a well working system it's a great product.
 
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jmole

Solar Enthusiast
So I went with the REC, and my experience so far is about what I thought it would be.

The hardware works. I haven't really stress tested it but the contactor closes when I flip the main switch and opens when it's off. Nice alternative to a big ol battery switch, to be honest. I actually removed the battery switch from the battery entirely because it was eating more power than the fuses and contactor and wiring combined. Maybe I got a bad sample, or it's unique to the Blue sea 6010?

But in terms of the REC, the software is just as bad as the documentation seems to imply, and ditto for the firmware. Its just poorly documented altogether. It feels like they are a hardware company that really understands hardware design, but then they hired an intern from the local high school to write code and documentation.

To be fair - it works pretty much out of the box with the Victron stuff if you follow the directions.

But if you want to do any kind of configuration, it seems like you're basically SOL unless you get ahold of their development team.

EDIT - might be wrong about the following, see thread below.

Like, for a smart BMS, the idea is that you can tell the charging devices to stop charging over CAN once you're at SOC 100%. great. And REC does that. But then the same logic that drives the CAN communication also drives the CHARGE contactor logic, so your contactor will open at 100% even if the devices have stopped charging.

To me, this is silly. The contactor should be there as a last resort safety measure, but there is essentially zero configurability to it's behavior, outside of some thresholding (and it's the same thresholding that's used to tell other devices to stop charging)

Anyway - I'm hoping I can get in touch with them and work these issues out. I really wish their firmware was open source so I could fix it myself, but c'est la vie.
 
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jwelter99

Solar Addict
So I went with the REC, and my experience so far is about what I thought it would be.

The hardware works. I haven't really stress tested it but the contactor closes when I flip the main switch and opens when it's off. Nice alternative to a big ol battery switch, to be honest. I actually removed the battery switch from the battery entirely because it was eating more power than the fuses and contactor and wiring combined. Maybe I got a bad sample, or it's unique to the Blue sea 6010?

But in terms of the REC, the software is just as bad as the documentation seems to imply, and ditto for the firmware. Its just poorly documented altogether. It feels like they are a hardware company that really understands hardware design, but then they hired an intern from the local high school to write code and documentation.

To be fair - it works pretty much out of the box with the Victron stuff if you follow the directions.

But if you want to do any kind of configuration, it seems like you're basically SOL unless you get ahold of their development team.

Like, for a smart BMS, the idea is that you can tell the charging devices to stop charging over CAN once you're at SOC 100%. great. And REC does that. But then the same logic that drives the CAN communication also drives the CHARGE contactor logic, so your contactor will open at 100% even if the devices have stopped charging.

To me, this is silly. The contactor should be there as a last resort safety measure, but there is essentially zero configurability to it's behavior, outside of some thresholding (and it's the same thresholding that's used to tell other devices to stop charging)

Anyway - I'm hoping I can get in touch with them and work these issues out. I really wish their firmware was open source so I could fix it myself, but c'est la vie.

That isn't the way it works with the Canbus and Victron - you have something configured incorrectly.

The "main" contactor does not open when you reach 100% SOC. It opens when low/high cell voltage or temperature limits are reached. These are set higher then stop-charging and lower than stop-discharge voltage levels so in normal operation you should never reach them.

DVCC handles all the charge current (CCL) and voltage (CVL), and discharge current (DCL) settings and that works really nicely. As cells reach the start-of-balance during a charge you see the charge current gracefully be reduced to allow the active balance to do it's thing, before the end of charge voltage is reached. So you get a top balance across the cells at the end of each charge cycle.

Also once stop-charge is reached you see the CVL drop to float levels to allow the charge equipment to service whatever loads if they can to keep the pack topped up.

If you send a screenshot how it's setup I can try to help you, if not email REC. They always respond within the next day.
 
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jmole

Solar Enthusiast
That isn't the way it works with the Canbus and Victron - you have something configured incorrectly.

The "main" contactor does not open when you reach 100% SOC. It opens when low/high cell voltage or temperature limits are reached. These are set higher then stop-charging and lower than stop-discharge voltage levels so in normal operation you should never reach them.

DVCC handles all the charge current (CCL) and voltage (CVL), and discharge current (DCL) settings and that works really nicely. As cells reach the start-of-balance during a charge you see the charge current gracefully be reduced to allow the active balance to do it's thing, before the end of charge voltage is reached.

If you send a screenshot how it's setup I can try to help you.

Yes, I realized that today after finally fully charging the battery and seeing that the contactor indeed stayed closed.

The BMS reduced it's Charge Current Limit (CCL) as the voltage increased, and finally set it to zero when I topped the battery off this morning from the Victron inverter. That said - I just popped open the remote monitor and was surprised to see this:
1625606394320.png

Earlier in the day, the CVL was 14.1V and the CCL was near zero.
This also sort of aligns with my voltage settings shown in the settings page here:
IMG_2425.jpeg

This is what the docs say:
When the highest cell reaches the Balance start voltage setting, the charging current starts to ramp down to 1.1 A until the last cell rises to the End of charge voltage. At that point the Maximum charging voltage allowed is set to Number of cells x (End of charge voltage per cell – 0.5 x End of charge hysteresis per cell). End of charge SOC hysteresis and End of charge cell voltage hysteresis is set to prevent unwanted switching. SOC is calibrated to 100 % and power LED light is on. Charge optocoupler is turned off.

By my calculations, that's 4⨉(3.55-0.2*0.25) = 4⨉(3.55 - 0.05) = 4⨉3.5 = 14V.

WRT my earlier point about the contactor - I realize now that there is a different between the charge optocoupler and the charge relay - the charge optocoupler is not what controls the relay.

That said, I still maintain that the documentation for their product is hot garbage compared to Orion Jr 2 for example. Like the least they could do is put in a few little graphs that show thresholds, hysteresis points, and behavior.

The other irritation I have with their product is that the cell voltage readings are extremely noisy when the inverter is on, which can make balancing problematic. Ideally you want to balance to <20mV between cells but when your voltage readings are jumping around by 5-10mV between cycles, it's just not possible, which IMO kinda ruins the point of having an active balance system in the first place.

Anyway, curious to hear more from you - my biggest concern with the pack right now is that some cryptic error will happen with the BMS while I'm on the road and I'll lose power. Thinking now about bringing the Bluesea switch back as a bypass switch so I can bypass the contactor as a last resort in that case.
 

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Heap64

Solar Addict
I too recently setup the REC and also found the documentation a bit lacking. It took me a bit to even find the right drivers to make a windows 10 laptop to work with their cable. But eventually I got there. It shouldn't be that hard after spending that much money

I too would love to see others settings if I need to tweak anything from basically the defaults.
 

jwelter99

Solar Addict
Yes, I realized that today after finally fully charging the battery and seeing that the contactor indeed stayed closed.

The BMS reduced it's Charge Current Limit (CCL) as the voltage increased, and finally set it to zero when I topped the battery off this morning from the Victron inverter. That said - I just popped open the remote monitor and was surprised to see this:
View attachment 55271

Earlier in the day, the CVL was 14.1V and the CCL was near zero.
This also sort of aligns with my voltage settings shown in the settings page here:
View attachment 55275

This is what the docs say:


By my calculations, that's 4⨉(3.55-0.2*0.25) = 4⨉(3.55 - 0.05) = 4⨉3.5 = 14V.

WRT my earlier point about the contactor - I realize now that there is a different between the charge optocoupler and the charge relay - the charge optocoupler is not what controls the relay.

That said, I still maintain that the documentation for their product is hot garbage compared to Orion Jr 2 for example. Like the least they could do is put in a few little graphs that show thresholds, hysteresis points, and behavior.

The other irritation I have with their product is that the cell voltage readings are extremely noisy when the inverter is on, which can make balancing problematic. Ideally you want to balance to <20mV between cells but when your voltage readings are jumping around by 5-10mV between cycles, it's just not possible, which IMO kinda ruins the point of having an active balance system in the first place.

Anyway, curious to hear more from you - my biggest concern with the pack right now is that some cryptic error will happen with the BMS while I'm on the road and I'll lose power. Thinking now about bringing the Bluesea switch back as a bypass switch so I can bypass the contactor as a last resort in that case.

I'm using a MultiPlus 3000 as the charger/inverter and don't see the noise you reference and the cell voltages rarely jump more than 1 to 4mv between samples during balancing. My charge of a 840Ah pack routinely end (SOC goes to 100%, CCL is 0, and CVL drops to float levels) with voltages being equal or within 1mv. Even at the bottom when down around 15% SOC left I am only out by ~10mV from high to low cell.

Perhaps you are getting some AC ripple across the inverter to the battery DC side that is being picked up?

I do agree the manuals are not fantastic and leave you having to read carefully and sometimes diagramming it out yourself. Pretty typical for small volume tech products produced in Europe actually. Remember English is not their first language, and the manuals clearly show this.

As for reliability I recently put together a system with a neighbor for his class-C. He's been on the road now for about 4 weeks with it and zero issues. He reports in everything is working well and they are typically using 30% of the capacity overnight and it's fully recharged by solar/B2B by the next evening.

I've being keeping an eye on the VRM logs to make sure nothing unexpected and it all looks to be working well - nothing unexplained with the system overall.

The only gotcha right now is a couple Victron issues:

1) With the 2.7x release of the Cerbo GX firmware that causes WiFi to get dropped; but data is still logged internally and pushed up to VRM when WiFi is forced to reconnect. Victron is working on this (I've been in dialogue with them). The reason to use 2.7 is Victron/REC have added support for the REC BMS alarms so right on the Touch-50 panel you get any critical BMS alarms pop up. Makes it a bit easier to have a single interface.

2) VRM will report cell voltages to 2 decimal places; so the min/max cell stuff is clipped from the full 3 decimal places. So you see some weird graph traces due to the rounding (3.344 will be 3.34, and 3.345 will be 3.35 - showing a 0.01V split on the Cerbo, but on the REC you will see it's really only 0.001V). Trivial issue but if we get graphing of min/max cells it might as well be right.

I am pretty critical over stuff working as intended and quality of support and can't knock REC. They are far more responsive and knowledgeable than the typical Victron sales engineer and support group.

Batrium is not any better, perhaps slower support and more arrogant. Not dealt with Orion but they seem to be on top of things. The China suppliers are what they are. The local resellers of the China product likely give you answers but you can't be sure it is correct as they are just the messengers.

Also agree that having open source firmware would be really cool as so much that could be done if the development environment was reasonable.
 

jmole

Solar Enthusiast
Perhaps you are getting some AC ripple across the inverter to the battery DC side that is being picked up?
Maybe some DC ripple from the inverter itself, but the AC loads I was testing with were a hairdryer and a space heater so no ripple there AFAIK. I could feel the 4/0 battery cables pulsing though, so it's clear there is some serious EM energy moving around when the inverter is pulling 250A.

But comparing the voltages reported by the BMS software to my handheld fluke multimeter (which had essentially zero drift), it was clear that the BMS wasn't doing a great job of filtering the noise.

After thinking more about the cryptic failure issue, I decided I'm going to add another switch to my battery that powers the contactor directly, so I can force it to close if something weird happens on the road and the BMS refuses to cooperate.

The other failsafe I'm considering is the opposite of that - a switch to force it open in case something weird happens – basically a series cutoff for the other two contactor signals.

I'm not really worried about day to day - more like edge cases. One of the BMS fuses blows. Kid spills water and somehow it gets in the wrong place. Stuff like that.
 

jwelter99

Solar Addict
Maybe some DC ripple from the inverter itself, but the AC loads I was testing with were a hairdryer and a space heater so no ripple there AFAIK. I could feel the 4/0 battery cables pulsing though, so it's clear there is some serious EM energy moving around when the inverter is pulling 250A.

But comparing the voltages reported by the BMS software to my handheld fluke multimeter (which had essentially zero drift), it was clear that the BMS wasn't doing a great job of filtering the noise.

After thinking more about the cryptic failure issue, I decided I'm going to add another switch to my battery that powers the contactor directly, so I can force it to close if something weird happens on the road and the BMS refuses to cooperate.

The other failsafe I'm considering is the opposite of that - a switch to force it open in case something weird happens – basically a series cutoff for the other two contactor signals.

I'm not really worried about day to day - more like edge cases. One of the BMS fuses blows. Kid spills water and somehow it gets in the wrong place. Stuff like that.

I wonder if the cell sense leads are somehow picking up the EMI that the inverter is generating in its leads? I am using the provided REC harness but have the sense wires routed away from the bus bars/high amp leads and only crossing them at 90 degree to them.

For my main contactor I use a BlueSea 7713. It has a remote position for BMS control, a locked off setting, and a manual on, so it has the ability to override the REC if needed. I have that in there for maintenance so I didn't need a separate ESO as this is a system I may need to walk someone through remotely so less knobs and stuff to touch the better ;)

The downside is expensive but it was not a budget build.
 

Just John

Photon Sorcerer
I don't know what the balancing power is on my Overkill Solar 4s BMS, but it's working great on my EVE 280Ah cells.

If you have the BMS telling the solar charge controller to stop charging, if there is a load on the system that the PV output could normally handle without dipping into the battery, how would that work? So far, I don't see a need for the BMS to communicate, but my system is small with only two 4s batteries for 560Ah.
The small active balance current needs two things to work properly.
1. Well top balanced cells.
2. Cells with "close enough" self discharge rates.

Once cells are top balanced, all it needs to do is correct any self discharge differences.
 

Philtao

Sailor, EE & Designer of the TAO BMS
To answer some of the questions you have regarding the comparison of REC BMS and Orion Jr, the attached document might give you some pointers. It is a BMS features comparison chart for Orion Jr BMS2, REC ABMS, 123 Smart BMS, and TAO BMS. It covers more than 100 features and specifications.

As you might guess ;) I can talk about the TAO BMS features in response to what the different posters in this thread deem to be important:
  • "ability to tell the WS500 and the Victron Multiplus II and the solar panel controller to stop charging, without needing to close a contactor to accomplish it"
    TAO: yes CANBUS + wire remote control (as a potential backup / failsafe)

  • "The big con with the ..., of course, is that you're limited to 150mA of passive balancing current"
    TAO: 4A active inductive balancing current (2A to charge lowest cell and 2A to discharge highest cell)

  • "One of the favorite things I like about the Orion is the Orion Connect which allows me to see various stats and trends remotely"
    TAO: yes - keeps lifetime history of measures and events log. Accessible on local WiFi and on the Cloud if the BMS is connected to a WiFi with Internet access

  • "I haven't really stress tested it but the contactor closes when I flip the main switch and opens when it's off"
    TAO: the remote display panel has an emergency button that activates the selected contactors (up to 6) with a long press (there is a programmable time delay between contactors so that for example a LA battery can be connected in parallel before cutting off the alternator or isolating the main battery).
    The "stress testing" part is quite important as programmation and connection of different equipment becomes more complex and therefore more prone to errors and failures. There is an option to simulate individual cell voltage and temperature to be sure the it produces the expected outcome.

  • "some cryptic error will happen with the BMS while I'm on the road and I'll lose power"
    TAO: a combination of 4 leds at the dashboard gives you an indication on the type of error the BMS has detected. You can also set a user defined delay between detection of the error and the activation of the relay (gives you time to investigate and hopefully fix the problem before loosing power). You can also set warning levels that tells you something is out of bound but does not activate any relays.

  • "having open source firmware would be really cool as so much that could be done if the development environment was reasonable"
    TAO: I am not planning to make the BMS firmware open source as this is the heart of the system and key to the safety of the system (it is complex and has been stable for a long time - it has a simple API that we can easily evolve to support additional functionality required by users).
    A large part of the logic and all the external communication happens in the Monitor (Python, web server, CANbus,...). It communicates with the BMS using the BMS API and I could consider making the Monitor firmware open source (I just need to make a proper user documentation for it so that I do not create a support nightmare for myself) à suivre...
 

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Just John

Photon Sorcerer
FWIW my Orion has no problems keeping my 560Ah 48v bank balanced. It’s balanced within an hour of reaching 100% SoC.
Not surprised. It seems a well made BMS from what I have read, just expensive.
Active balancers aren't magic, if you are not discharging to get that weakest cell down to the bottom, most don't need something else to go wrong. With properly top balanced cells, the BMS just has to balance out the self discharge difference between cells. Depending on how fast you charge and discharge, active balancer might get a couple of extra amp hours out of a battery near the end. But it will negate your top balance, forcing you to charge higher than you really should (but I guess if you need that couple of extra amp hours........).
 
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