Victron, lithium and 12v

[campervanannie]

Single 300Ah Lithium in fact

And as an aside, that screenshot also shows that the AMT Starter Battery Trickle Charger is doing its thing perfectly as well

I can never remember the technical stuff it’s big solar big battery and magic blue boxes in Annie’s world.n

 

[merl]

And as an aside, that screenshot also shows that the AMT Starter Battery Trickle Charger is doing its thing perfectly as well

Really? Don't fink so. 13.4v - 13.6 is typical manufacturers data for floating. 12.78 is better than nothing and ensures the van starts but far from perfect WRT longevity.
Why so low? I thought the ablemail was super adjustable?

 

[Nabsim]

Sounds like you had same as I had then Annie. I just make sure I aim fully charged every now and then if I can't easily get 100% from solar or driving

 

[merl]

Sounds like you had same as I had then Annie. I just make sure I aim fully charged every now and then if I can't easily get 100% from solar or driving

Mine does exactly the same. I've monitored it closely and mine misbehaves in this way because the device doesn't respond and 'count' very low currents even though the display shows them. Consequently if you have a low drain such as 60 milliamps from a PDU, over a layup period of many weeks this slow drain 24-7 will result in a considerable loss of battery capacity but because it doesn't get counted the battery capacity display stays at 100% and a large error forms. Very careful choices of the solar restart voltage can keep the error to a minimum but this isn't an option on a lot of controllers, also the wrong setting could be harmful to lithium batteries so probably best to leave these settings alone unless you know what you're doing and simply give the van an overnight charge on EHU occasionally/before going away.

 

[wildebus]

Something that can happen with the BMVs, especially with Solar Setups, is a premature reset to 100% SOC.
The Victron BMV and SmartShunts use a combination of voltage over a certain amount and current under a certain value for a specified duration which resets the State of Charge to 100% and it is possible to have a false reset especially with solar.
For this reason, I tend to set the voltage at a higher level than the chargers are set to so a false reset can not happen (my screenshot in post #4 shows the "charged voltage" set at 15.0V for example).

It does mean that the BMV will only ever reach 99.9% SOC, but as I know that is pretty right.

 

[Nabsim]

Mine does exactly the same. I've monitored it closely and mine misbehaves in this way because the device doesn't respond and 'count' very low currents even though the display shows them. Consequently if you have a low drain such as 60 milliamps from a PDU, over a layup period of many weeks this slow drain 24-7 will result in a considerable loss of battery capacity but because it doesn't get counted the battery capacity display stays at 100% and a large error forms. Very careful choices of the solar restart voltage can keep the error to a minimum but this isn't an option on a lot of controllers, also the wrong setting could be harmful to lithium batteries so probably best to leave these settings alone unless you know what you're doing and simply give the van an overnight charge on EHU occasionally/before going away.

I haven't noticed this happening with mine, the one occasion I had the problem it was after I had disconnected the hab battery bank causing the shunt to reset to 100% on power on. As soon as the Victron update came out I changed the setting so it couldn't happen again.

If mine is ever 'laid up' it has the solar and is stored outside so that may be why I haven't had the problem you mention.

 

[merl]

If mine is ever 'laid up' it has the solar and is stored outside so that may be why I haven't had the problem you mention.

I'm not using the Victron shunt/BMV but the less expensive AiLi TR16. Probably a bit of a shortcoming with a budget unit?

 

[Nabsim]

I'm not using the Victron shunt/BMV but the less expensive AiLi TR16. Probably a bit of a shortcoming with a budget unit?

Or it may just be that mine stays at 100% if left for most months of the year. Or whatever it may have lost was replaced on journey out. Who knows, I may have jinxed it now lol

Edit: When the van is parked up to be left a while the draw is extremely low, 300W on solar on the roof can stay on top of that even through Winter. If short term for an odd week if it dropped I would recharge with the genny so I probably wouldn't see it happen

 

[merl]

I think solar settings will also play a part. Assuming the battery has just finished fully charging , the mppt cuts off and the battery voltage now falls back to 13.6v because that's the resting voltage of lithium. There's bound to be a slight drain on the battery, even the BMS itself will draw a slight current, also the mppt, PDU etc. The point at which the solar cuts in again and starts recharge will depend upon the actual design of the charger and if adjustable it's 'restart' voltage setting, depending on what this voltage is the battery capacity could drop considerably because the discharge curve of lithium is so flat, just half a volt equals about 50% capacity.
So the mppt cuts back in and starts charging but there's not a lot of sun and the battery only gets back up to say 60% before the sun goes down....what happens in the morning? Does the charger carry on from where it left off the previous evening or does it stay off because the battery voltage is now very slightly over the restart voltage?
All very system and settings dependant but interesting...... probably not though unless you're me

 

[gasgas]

What he said !

Yeah. Agreed.
I don't do all that monitoring stuff. I know when my batteries are flat because the lights go out. Simples. But I would agree, you need to investigate if things stop working unexpectedly.
I have 200W of solar and lithium batteries. No Victron or any monitoring stuff. I haven't plugged my van into EHU since August, just relying on cloud cover to keep the batteries charged. I was running my newly fitted diesel heater last night for 4 hours and the lights didn't go out, the voltmeter didn't go below 12v and all was fine. And I was listening to the radio.
I live in blissful ignorance and sleep well.

 

[Nabsim]

I think solar settings will also play a part. Assuming the battery has just finished fully charging , the mppt cuts off and the battery voltage now falls back to 13.6v because that's the resting voltage of lithium. There's bound to be a slight drain on the battery, even the BMS itself will draw a slight current, also the mppt, PDU etc. The point at which the solar cuts in again and starts recharge will depend upon the actual design of the charger and if adjustable it's 'restart' voltage setting, depending on what this voltage is the battery capacity could drop considerably because the discharge curve of lithium is so flat, just half a volt equals about 50% capacity.
So the mppt cuts back in and starts charging but there's not a lot of sun and the battery only gets back up to say 60% before the sun goes down....what happens in the morning? Does the charger carry on from where it left off the previous evening or does it stay off because the battery voltage is now very slightly over the restart voltage?
All very system and settings dependant but interesting...... probably not though unless you're me

I don't know what actually happens but from what I see I would say my solar and my B2B would try to charge whatever the battery state then drop to float if not needed. I could well be wrong g though as if I am there to look then I would have used some battery at least. I know this happens with the B2B if I start engine when battery are full, with solar I think the Victron does check at intervals. It probably gives all the info in the manuals

 

[wildebus]

Yeah. Agreed.
I don't do all that monitoring stuff. I know when my batteries are flat because the lights go out. Simples. But I would agree, you need to investigate if things stop working unexpectedly.
I have 200W of solar and lithium batteries. No Victron or any monitoring stuff. I haven't plugged my van into EHU since August, just relying on cloud cover to keep the batteries charged. I was running my newly fitted diesel heater last night for 4 hours and the lights didn't go out, the voltmeter didn't go below 12v and all was fine. And I was listening to the radio.
I live in blissful ignorance and sleep well.

How do you know if the voltage didn't go below 12V? as you said "No Victron or any monitoring stuff."?

 

[gasgas]

Ah yes I see what you mean. I don't have an App that follows and records every point nought of a volt throughout the year, but I do have some monitoring stuff as there is a voltmeter on my analogue-with-switches-that-join-two-bits-of-metal-together control panel. If I press a button next to it, it shows the water level. It doesn't show points of a volt but it is good enough to tell you if the battery is healthy, the sun is shining on the solar panel, or

if the volts are getting a bit low.

 

[marchie]

Ah yes I see what you mean. I don't have an App that follows and records every point nought of a volt throughout the year, but I do have some monitoring stuff as there is a voltmeter on my analogue-with-switches-that-join-two-bits-of-metal-together control panel. If I press a button next to it, it shows the water level. It doesn't show points of a volt but it is good enough to tell you if the battery is healthy, the sun is shining on the solar panel, orView attachment 146820 if the volts are getting a bit low.

View attachment 146820

Why does one need a gauge for water level? It always is ...

Steve

 

[campervanannie]

So on mine it usually says Bulk or float but if you look at my pictures it says open what does that mean?

 

[Nabsim]

So on mine it usually says Bulk or float but if you look at my pictures it says open what does that mean?

There is a relay fitted Annie that you can use to activate something if you wish to. The open refers to that. You can't set at what percentage SoC the relay opens and closes. I don't know if you make use of this function or not but it looks after itself and can be ignored.

 

[wildebus]

There is a relay fitted Annie that you can use to activate something if you wish to. The open refers to that.

The Bulk/Absorption/Float info will be on the Charger Screens - so when you go to the MPPT Controller or the Multiplus Smart-BMS unit you will get info on that. The Open/Close is on the BMV-712 and is for the relay on the Shunt, as Neil says above.

You can't set at what percentage SoC the relay opens and closes. I don't know if you make use of this function or not but it looks after itself and can be ignored.

You can indeed programme the relay on the BMV to activate and deactivate at different voltages and can be quite handy in fact. On my last camper, the Stripey Clarence, I used to activate the relay at a high SOC in order to turn on the electric water heater and then when the SOC dropped to a certain lower SOC, turn off the water heater.
Annie, you aren't using the relay for anything in your setup I think. (I would think at the very most 5% of BMV users have the relay connected).

 

[campervanannie]

The Bulk/Absorption/Float info will be on the Charger Screens - so when you go to the MPPT Controller or the Multiplus Smart-BMS unit you will get info on that. The Open/Close is on the BMV-712 and is for the relay on the Shunt, as Neil says above.


You can indeed programme the relay on the BMV to activate and deactivate at different voltages and can be quite handy in fact. On my last camper, the Stripey Clarence, I used to activate the relay at a high SOC in order to turn on the electric water heater and then when the SOC dropped to a certain lower SOC, turn off the water heater.
Annie, you aren't using the relay for anything in your setup I think. (I would think at the very most 5% of BMV users have the relay connected).

Did I ever tell you how wonderful you are Mr Wildebus and the rest of you with your very useful help and information.

 

[gasgas]

Why does one need a gauge for water level? It always is ...

Steve

One needs a gauge for water level so one can tell when the tank is about to run out of water and therefore you need to go to Europe where you can call in at the next village Aire and replenish the tank.
Whereas in the UK you need to book into a camp site and pay £25 to refill the tank.
Pssst . . . on the Isle of Man I know three places where you can fill the tank (and dump the cassette ) free of charge . . . . .but it's more expensive to get to the IOM from the UK than it is to get to Europe.

 

[marchie]

One needs a gauge for water level so one can tell when the tank is about to run out of water and therefore you need to go to Europe where you can call in at the next village Aire and replenish the tank.
Whereas in the UK you need to book into a camp site and pay £25 to refill the tank.
Pssst . . . on the Isle of Man I know three places where you can fill the tank (and dump the cassette ) free of charge . . . . .but it's more expensive to get to the IOM from the UK than it is to get to Europe.

'Whoosh'

Steve