Optimal Eve 280ah REC Abms settings with Victron Battery Protects, Victron 3000kva Multiplus ii

[HelenLo]

Hi all,

We’ve been building our system onboard our boat. We have 12 x Eve 280ah cells wired in 3p4s We’re now at the stage of programming our settings and connecting our Rec Active BMS, Victron 3000 kva inverter and battery protects, which we have one for 12 v load and one before batteries for incoming charge from solar, wind etc. We’re going to use a Raspberry Pi for monitoring.

My question is optimal settings, I’m seeing so much online and want to get the best settings that prolongs the life of the batteries but utilises the active balancing of the abms.

I’m thinking of:

3.6v for high voltage disconnect
3.45v for absorption for 1 hour
3.35v for float
2.9v for low voltage disconnect

Does this wound optimal for this system? Interested to hear from other people with a similar set up/ configuration.

Helen

 

[svsagres]

I don't think you need the absorption set for that long, as I recall my settings are only a couple of minutes. As I recall, it will stretch it out if it needs to balance the cells. That said, I also don't know that you'll see much of the shoulder at 3.45 for it to balance reasonably. On my boat, my REC will take my battery up to 14.5v for a few minutes, then let it drift down to 13.8 or 13.9v, and hold it there. If it drops below a lower threshold, it will reset the limit to 14.5, or it will also will want to go back there after a period of time (a week or two? I don't recall right now, and I'm not aboard so can't check).

The cells are rated for 3000+ cycles, so even if I were to cycle it every day, that's some 8 years of daily cycling, and realistically I don't cycle them anywhere near that frequently. Also, after 18 months, my cells (230Ah cells in a 2p4s configuration) are only 0.003v out of balance. Other than my first cycle, I have not seen my system ever actually try and balance the cells.

I have mine set to 3.45 for float, but only use that capacity when I'm aboard. Otherwise, I use the DVCC override on my Cerbo and drop the system voltage to 13.3v or 13.2v. I generally refer to this as "storage mode" or "Dock potato mode" This works though, because all my charge sources are integrated (Victron MPPTs, MultiPlus) so I only use the main contactor to as an HVC. It has never fired unintentionally in the 18 months we've had the system on the boat, and has actually only been actuated a handful of times. My wakespeed probably wouldn't listen to this DVCC override (as it listens directly to the BMS), but it's only ever in use while I'm aboard.

 

[Rocketman]

Your low voltage disconnect may be too high for a high load on the inverter. If your batteries are about halfway or 2/3rds down and you run a high load - say a microwave. There will be some voltage drop due to the load. You need to test your system and find out if that is ok or if it trips the low voltage disconnect.

Also, set your inverters low voltage disconnect higher than the bms’s. That way if you accidentally trip something- it is your inverter that stops and not the bms. Bms’s can be harder to restart.

 

[svsagres]

Your low voltage disconnect may be too high for a high load on the inverter. If your batteries are about halfway or 2/3rds down and you run a high load - say a microwave. There will be some voltage drop due to the load. You need to test your system and find out if that is ok or if it trips the low voltage disconnect.

Also, set your inverters low voltage disconnect higher than the bms’s. That way if you accidentally trip something- it is your inverter that stops and not the bms. Bms’s can be harder to restart.

In this kind of a system, the settings are sort of all one and the same. Yes, you set a low voltage cutoff on the inverter, but as long as it's getting commanded by the BMS (via the VenusOS running on the Raspberry Pi they mention) the BMS limits will override whatever is configured voltage/current wise on the inverter/charger. I tend to configure my MPPTs and other equipment conservatively, so if the BMS goes Tango-Uniform, I can throw the contactor manually and limp home based just on the settings in the other equipment, and know that I won't overcharge/undercharge my battery.

 

[HelenLo]

Thanks all, so reading these responses and looking at Will’s suggestions for settings for conservative usage intended for 5000+ charge cycles. These cells are rated for 6000 plus cycles and would love to look after them.

I’m looking at:

REC ABMS settings:
14.1v absorption
13.6v float
12v inverter cut off

And then slightly lower settings for the Victron equipment as svsagres suggests in the case of needing to limp back. We’re using Victron battery protects in the place of the contactors in the rec system. Not even sure these can be thrown manually, maybe just a case of adjusting settings but a very good point that I’d love to know before we set out!

On a separate note, wiring of the windlass we have to our house bank, would this better through our starter battery to protect the cells?

 

[HelenLo]

And low voltage disconnect for the inverter should be higher for the inverter than the bms.

So perhaps 11v on the bms and 12v on the inverter?

 

[svsagres]

Thanks all, so reading these responses and looking at Will’s suggestions for settings for conservative usage intended for 5000+ charge cycles. These cells are rated for 6000 plus cycles and would love to look after them.

I’m looking at:

REC ABMS settings:
14.1v absorption
13.6v float
12v inverter cut off

And then slightly lower settings for the Victron equipment as svsagres suggests in the case of needing to limp back. We’re using Victron battery protects in the place of the contactors in the rec system. Not even sure these can be thrown manually, maybe just a case of adjusting settings but a very good point that I’d love to know before we set out!

On a separate note, wiring of the windlass we have to our house bank, would this better through our starter battery to protect the cells?

You can’t use a battery protect for the multiplus, as the current flows both ways while the BatteryProtects can only handle current in one direction.

My charge bus is controlled by a BlueSea 7713. I like it for a couple of reasons: It’s 500a rated, it only consumes about 7ma while holding, I can manually force it on, and I can also manually lock it off. I work in industrial environments for my day job, so the ability to do my own lock out/tag out appeals to me.

For my house DC loads, I’m using a batteryprotect, and if I need to force it on, I can use a jumper to +12V.

 

[svsagres]

On a separate note, wiring of the windlass we have to our house bank, would this better through our starter battery to protect the cells?

The biggest issue with your windlass is what is going to happen when it stalls out due to a fouled anchor or similar. It’s basically going to go to a near short circuit. You’ll likely pop the fuses. Also, the high inrush current can erode the contacts on the control solenoid.

I was worried about this enough that I stuck with a cheap marine start battery for my engine, and just keep it charged up with an Orion-Tr.

 

[TomC4306]

3.6v for high voltage disconnect
3.45v for absorption for 1 hour
3.35v for float
2.9v for low voltage disconnect

Perfect.

 

[HelenLo]

The biggest issue with your windlass is what is going to happen when it stalls out due to a fouled anchor or similar. It’s basically going to go to a near short circuit. You’ll likely pop the fuses. Also, the high inrush current can erode the contacts on the control solenoid.

I was worried about this enough that I stuck with a cheap marine start battery for my engine, and just keep it charged up with an Orion-Tr.

We're continuing with a regular lead-acid starter battery and charging with the Orion-TR also.

Would it upset the system if we wired the windlass into this opposed to the house bank? We only use the windlass when the engine is running.

Many thanks for your replies, super appreciated.

 

[HelenLo]

In this kind of a system, the settings are sort of all one and the same. Yes, you set a low voltage cutoff on the inverter, but as long as it's getting commanded by the BMS (via the VenusOS running on the Raspberry Pi they mention) the BMS limits will override whatever is configured voltage/current wise on the inverter/charger. I tend to configure my MPPTs and other equipment conservatively, so if the BMS goes Tango-Uniform, I can throw the contactor manually and limp home based just on the settings in the other equipment, and know that I won't overcharge/undercharge my battery.

I think this is where I have made a mistake as I've used 2 battery protects. One for the charge system and the other for dc loads. But I haven't put a contactor in to shut down the inverter using data communicated from the BMS.

I just have the Inverter and BMS connected to the Raspberry Pi via cable and can connections. So I can set the settings for the inverter on the victron system but it wont be communicating with the BMS. Is that ok in the short term until I sort out an extra contactor?

 

[svsagres]

We're continuing with a regular lead-acid starter battery and charging with the Orion-TR also.

Would it upset the system if we wired the windlass into this opposed to the house bank? We only use the windlass when the engine is running.

Many thanks for your replies, super appreciated.

That’s often done. I know that on some larger vessels they have a dedicated battery forward, as it means they don’t need to run heave gauge wiring from the engine compartment (usually) to the forward cabin/vee berth to power the windlass.

 

[svsagres]

I think this is where I have made a mistake as I've used 2 battery protects. One for the charge system and the other for dc loads. But I haven't put a contactor in to shut down the inverter using data communicated from the BMS.

I just have the Inverter and BMS connected to the Raspberry Pi via cable and can connections. So I can set the settings for the inverter on the victron system but it wont be communicating with the BMS. Is that ok in the short term until I sort out an extra contactor?

Just make sure that you do not have your inverter behind a batteryprotect, as the batteryprotect can only handle current flowing in one direction while your inverter/charger can obviously push current in both directions.

If you have the control and venusos going, then it’s entirely likely that your inverter is being controlled by the BMS. Check to make sure you have DVCC enabled in VenusOS and that it has found/selected the REC. If that’s the case, then it will also control the multiplus.

 

[HelenLo]

Just make sure that you do not have your inverter behind a batteryprotect, as the batteryprotect can only handle current flowing in one direction while your inverter/charger can obviously push current in both directions.

If you have the control and venusos going, then it’s entirely likely that your inverter is being controlled by the BMS. Check to make sure you have DVCC enabled in VenusOS and that it has found/selected the REC. If that’s the case, then it will also control the multiplus.

The battery protects don't incorporate the inverter. Only the dc loads and charging.

I didn't think the BMS would control the inverter if there is no contactor for shut down in-between?

I did manage to get through to Rec who has said I can add this later but it shouldn't hold up going live with the system.

I'm just about to programme everything which is making me more nervous than all the wiring and making sure everything is connected properly!!

Thanks for the info on the windlass. We don't have a battery forward but we're 12.89m so not so much of a run...

 

[svsagres]

The battery protects don't incorporate the inverter. Only the dc loads and charging.

I didn't think the BMS would control the inverter if there is no contactor for shut down in-between?

I did manage to get through to Rec who has said I can add this later but it shouldn't hold up going live with the system.

I'm just about to programme everything which is making me more nervous than all the wiring and making sure everything is connected properly!!

Thanks for the info on the windlass. We don't have a battery forward but we're 12.89m so not so much of a run...

Properly designed, your contactor/batteryprotects should never operate. Through the Cerbo, the BMS voltage and current limits will be forwarded to the inverter/charger, so it will follow those commands.

If I was you, I'd look at slightly reorganizing your setup, with the inverter/charger, and your charge sources behind a contactor, and have that on the HVC side of the world, and one of the battery protects being a LVC and powering your DC loads. This is my configuration, and works really well. And the contactors have never, ever, fired, except when I've deliberately thrown the toggle switch.