Victron VenusOS driver for serial connected BMS available - LLT/JBD / Daly Smart / ANT / JKBMS / Heltec

BigDean

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@BigDean, the 200A model use a relay to switch the battery on/off while the 100A model use a bank of FETs. Both work fine, but I don't think it is economical to add enough FET chips to handle 200A, while the relay (this one with a precharger which is good) has some other drawbacks like being slower to switch.

If the 100A will be enough for your system, then I would suggest that model rather than the relay.
How do you know it will be enough for your needs? That depends on the power you need and intend to draw. 100A x 51V = 5100Watts so if you have a 5kW inverter 100A is your limit in any case.

You need the RS485 or UART interface. The driver don't use CAN. If you can make sure it has an extra interface. On the JBD the bluetooth normally is installed on the UART, so if you get the RS485 port extra then that mean you have the bluetooth and connection to the driver at the same time which is nice.

This will top balance your battery, but you will have to give it time to do that. So build your cells and install the BMS and charge it to around 80-90%. Then disconnect the charging and set the BMS to balance always (and not just on charging) and leave it for about a week. Check daily if the cells have settled and if it is still balancing and you can also top up the charge a bit if you want. You can extend this to two weeks if your battery needs more time. Then switch the balancing back to only on charge and you can begin using it in your system. The BMS should then keep your cells balanced from there on.
Thank you very much for this. Invaluable.

It is a 5kw inverter, so the 100A will be the best.

As always with Aliexpress, the advert is not 100% clear, but I think this includes the bluetooth and UART/RS485 connections....: https://www.aliexpress.com/item/100...o.store_pc_groupList.8148356.1.16387277X9TlrE

So hopefully I wont need any additional cables/interfaces!

Thanks again for your help.
Dean
 

Just John

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Thank you very much for this. Invaluable.

It is a 5kw inverter, so the 100A will be the best.

As always with Aliexpress, the advert is not 100% clear, but I think this includes the bluetooth and UART/RS485 connections....: https://www.aliexpress.com/item/100...o.store_pc_groupList.8148356.1.16387277X9TlrE

So hopefully I wont need any additional cables/interfaces!

Thanks again for your help.
Dean
I have this exact model (pretty sure, but I ordered from Alibaba). Be aware that the UART plug is used by both the PC (USB) and Bluetooth modules, so only one at a time.

The RS485 and Canbus have separate interfaces, thus can be used at the same time. Unfortunately, they always seem to be out of the Canbus interfaces.
 

BigDean

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I have this exact model (pretty sure, but I ordered from Alibaba). Be aware that the UART plug is used by both the PC (USB) and Bluetooth modules, so only one at a time.

The RS485 and Canbus have separate interfaces, thus can be used at the same time. Unfortunately, they always seem to be out of the Canbus interfaces.
Thanks for that. The description does seem to say you can use both with the “additional” box, but I “think” that additional box is included.

I will have this well before my batteries turn up so I can check.

Thanks
 

Just John

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Thanks for that. The description does seem to say you can use both with the “additional” box, but I “think” that additional box is included.

I will have this well before my batteries turn up so I can check.

Thanks
There is an additional box, it converts from serial port to USB. There is also a Bluetooth module, it converts from serial port to Bluetooth. Both plug into the same serial port. The RS485 and canbus also have converter boxes, but dedicated ports for each. The Bluetooth and USB modules use the same port, so only one can be used at a time.
 

BigDean

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There is an additional box, it converts from serial port to USB. There is also a Bluetooth module, it converts from serial port to Bluetooth. Both plug into the same serial port. The RS485 and canbus also have converter boxes, but dedicated ports for each. The Bluetooth and USB modules use the same port, so only one can be used at a time.
Ah!

I think it is the RS485 we use for the Cerbo, so think we are okay to use that and the Bluetooth. Ah well, on order now so we will see. 👍
 

lexio

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maybe it is handy if we have a hardware list with alibaba links with what is working
can i use any rapsberry pi ?
you have differend models
and how is the multi bms going and what are the problems whit that
 
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interestingfellow

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Hope someone can help. I am a newbie.....

Have ordered 16 x 280 cells for a 48v system and need to order the JBD BMS to match but I am confused on Aliexpress!

I THINK the options are:

200A with UART https://www.aliexpress.com/item/100...o.store_pc_groupList.8148356.8.43f57277iE2eTp
then add an RS485 interface

OR

100A "SMART" which includes UART/RS485 and CAN: https://www.aliexpress.com/item/100...o.store_pc_groupList.8148356.6.6ae86333H4dyct

Price doesn't matter, just want the right one that is most capable. Would prefer the 200A if that works.

And... again, sorry for newbie question; will this top balance or do I need something else to do that? If so, what would be a good option?

Thanks in advance.
Dean

PS, thanks @Louisvdw for your posts, it has made this journey much easier.
I made the mistake of not top balancing
YES YOU SHOULD TOP BALANCE!

Apparently the daly bms only burns of tens of milliamps from each battery during balancing: if you have a 280ah cell out by .1v, that will take days to balance out and that cell will be higher than the rest, running the risk of tripping your cell HVD.

*Ask me how I know
 

Just John

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interestingfellow

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Is it an Idea to put a additional (active) balancer on top of the Daly?
I found this one https://www.alibaba.com/product-det...4.html?spm=a2700.wholesale.0.0.1f4e59a69bDnJO
This has 4A capacity
The problem with this is needing to keep it on the batteries only after 3.4v/3.5v and above, and only until the cells are balanced for that cycle. You do not want it on while the pack is discharging, idle, or low SOC because it can throw off the balance

I used an active balancer because I did not top balance first, but I did adjust bulk/boost current to 5a (because that's what my active balancer can dissipate, and I brought absorption down to the pack voltage where the runner cell ran off, and then adjusted float to.1v below that. it took several cycles to get it balanced.
 

sparklehunt

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excuse a dumb question: Does this 'modbus RTU over RS485' integration with the Venus OS software give the same features as CAN enabled BMS? Like will the Venus then use that info to control a Victron inverter and/or MPPT charger?

Also, I can't find info on exactly what real benefits a CAN-enabled BMS (like Orion?, REC, Batrium, others?) will give you.

EDIT: I found the answer. From Orion:
<start quote>
Charge and Discharge Current Limits
For Lithium-ion cells, limiting cell voltages to within a specified voltage range is essential for protecting the cell from damage. However, there are many other parameters, such as temperature and current limits, which must also be monitored to protect the cells. To be able to control more than one parameter at once, the BMS incorporates different parameters into a maximum allowable charge and discharge current limit. Charge and discharge limits can be thought of as the realistic maximum amperage limits that a battery can discharge or charge at any given moment (expressed in 1 amp increments). Current limits are especially useful for variable current applications such as light mobile applications, because they allow these applications to slowly reduce current as a battery pack is emptied and therefore in- crease the usable range of a battery pack.
The charge and discharge current limits can be transmitted digitally from the BMS to other devices if the external device supports this. For example, most CANBUS enabled motor controllers and CANBUS enabled battery chargers support this. When a motor controller receives the current limit from the BMS, the motor controller knows that it cannot exceed the maximum current limit sent by the BMS even if the operator of the throttle calls for more power. Because the BMS incorporates many factors into the max- imum current limit, ensuring the current does not exceed this calculated current limit also ensures all the other associated battery parameters (such as minimum cell voltage, temperature, maximum C rate, minimum state of charge, etc) are enforced.
<end quote>
 
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Louisvdw

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give the same features as CAN enabled BMS?
Yes it does. The driver will then give you all the same features that a CANbus BMS will give (and in many cases more).
More details under the Wiki Features page. For example you will see on that page the last graph image show the charge and discharge limits that come from the driver.
 

jamiegreen

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Quick question, if I install this driver with my JK BMS and ccgx, and say I enter my max charge voltage on the ccgx to 80%, will the ccgx stop the charging at 80% or will this be ignored and instead charge until it hits what the BMS is set at? Also I have a 712 shunt, If I recall you can select which device the ccgx takes its SOC from? Obviously wanting to keep the 712 readings. Thanks.
 

Louisvdw

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will the ccgx stop the charging at 80%
Correct yes. The driver will tell the GX what the SOC value is, so the GX will know when 80% is reached. But the GX is still in control of the charge, so if you told it to stop at 80% then the GX will instuct the inverter/charger/MPPT to stop the charge.

you can select which device the ccgx takes its SOC from
In the latest VenusOS firmwares you choose which which Battery Monitor the system should use. I strongly suggest you use the BMS here and not the BMV712, and this will also be the default setting, but you can change it. The reason is simple that while your BMS is a very acurate shunt if does not have all the information. It was built for lead acid batteries and does not have the individual cell voltages, while your BMS does have this and will take this into account when calculating the SOC.

In the very latest firmware you can also see the value of the other Battery Monitor in your VRM and not only the one you selected.
 

jamiegreen

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Correct yes. The driver will tell the GX what the SOC value is, so the GX will know when 80% is reached. But the GX is still in control of the charge, so if you told it to stop at 80% then the GX will instuct the inverter/charger/MPPT to stop the charge.


In the latest VenusOS firmwares you choose which which Battery Monitor the system should use. I strongly suggest you use the BMS here and not the BMV712, and this will also be the default setting, but you can change it. The reason is simple that while your BMS is a very acurate shunt if does not have all the information. It was built for lead acid batteries and does not have the individual cell voltages, while your BMS does have this and will take this into account when calculating the SOC.

In the very latest firmware you can also see the value of the other Battery Monitor in your VRM and not only the one you selected.
Thanks for clearing that up.

I was under the assumption the reading given by the BMS was not always the most accurate (in general, not sure about the JK BMS) atleast not compared to a dedicated shunt, so I assume you'd say the BMS's ability to calculate SOC is accurate enough then? In this case installing the 712 would be of no use?
 

Louisvdw

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Thanks for clearing that up.

I was under the assumption the reading given by the BMS was not always the most accurate (in general, not sure about the JK BMS) atleast not compared to a dedicated shunt, so I assume you'd say the BMS's ability to calculate SOC is accurate enough then? In this case installing the 712 would be of no use?
Most of the BMS also measure using a shunt. And although the quality of the shunts might vary they tend to be quite accurate (less that 5% variation from what I have seen). The Victron BMV shunts are very high quality, but they only can measure the power in and out and does not have any measurement on cell level that a BMS has. For that they are not as useful in the lithium space if you already have a BMS in the system.

It's like comparing apples vs pears :).
If you want to measure the amount of energy you put into a battery, or the amount of energy you have used from the battery, then a shunt is a very accurate way to do that. The more accurate your shunt the more accurate your energy reading. We could also say shunt measure what has happened.

The difference come in when we are talking State Of Charge which is an aproximation of how much energy I should be able to get out of the battery or put back in to the battery. We could say this is a prediction of what will happen.

Lead Acid:
For LA based batteries there are no other measurements except to measure the current flow from a shunt. So then the prediction is the inverse of the measurement. If I know I have used 100Ah energy from the battery then my prediction(SOC) is that I should be able to add 100Ah of energy back.

Lithiums:
For Lithiums using a BMS we also know the current flow just like with LA, but now we also know the cell voltages, imbalances, resistance, etc. between these cells. So the BMS will have a much better prediction of what will happen and can adjust those predictions. Now the prediction is not just what happened, but also adjusted to include the other factors that is also influencing a battery.

So people think the dedicated shunt is better, but that is still thinking in Lead Acid terms. Rather spend the money on a better BMS. It's a much better option.
 
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