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Is Victron Battery Protect really protecting your batteries?

TheOx

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Battery Protect 12/24 220A - No Settings to support AGM typical low voltage cut-off recommendations?​

We need to protect an off-grid solar system that is primarily used to power an 240VAC 80W sewerage system aerobic pump that is supposed to operate 24/7 and at least 4 hours per day in unattended use (private camp-ground). The battery is a Eclipse Power 280AH Deep Cycle AGM. We have purchased a Battery Protect BP220 to provide a low voltage cut-off to inverter however I notice that the highest low voltage cut-off on the BP220 is only 12.0V [Setting 8]. This is way too low in my research which should be above12.5V to maximize cycles. When there is poor light or after use at night, we need the battery protect to kill the load until the batteries are charged sufficiently. There is no-one the during the week.

Am I making the correct assumptions about AGM ideal cut-off?
Am I using the right product?
Are there alternate settings (I doubt it)?
Is there a better product? (we are currently using KICKASS 12 Volt 140 Amp Dual Sensing Voltage Sensitive Relay and seems to do the job 12.8 cut-off)

Relative Notes:

Latronics LS-1012 1000W 12VDC Sine Wave Inverter​

The inverter cuts out at 10V too-low also.
1609929116808.png

Victron Battery Protect BP220 Settings
1609929277689.png



Eclipse Power 12V 280AH AGM Deep Cycle Battery
Nominal Voltage12V
Nominal Capacity (20HR)280.0 AH
DimensionLength: 520 ±3mm
Width: 235 ±3mm
Container Height: 235 ±3mm
Total Height (with Terminal): 241 ±3mm
Approx WeightApprox 62.2 Kg
TerminalT11
Container MaterialA.B.S.
Rated Capacity280.0 AH/14.0A (20hr,1.80V/cell,25°C)
Max. Discharge Current1850A (5s)
Internal ResistanceApprox 3.0mΩ
Operating Temp.RangeDischarge : -15 ~ 50oC (5 ~ 122oF)
Charge : 0 ~ 40oC (32 ~ 104oF )
Storage : -15 ~ 40oC (5 ~ 104oF)
Nominal Operating Temp. Range25 ± 3°C (77 ± 5°F )
Cycle UseInitial Charging Current less than 75A.
Voltage 14.4V~15.0V at 25oC (77o F)
Temp. Coefficient -30mV/oC
Standby UseNo limit on Initial Charging Current
Voltage 13.5V~13.8V at 25oC (77o F)
Temp. Coefficient -20mV/oC
Capacity affected by Temperature40oC (104oF) 103%
25oC ( 77oF ) 100%
0oC ( 32oF ) 86%
Self DischargeEclipse Power Deep Cycle AGM batteries may be stored for up to 6 months at 25oC(77oF) and then a freshening charge is required. For higher temperatures the time interval will be shorter.
 
Am I making the correct assumptions about AGM ideal cut-off?
I'm not sure, I don't know a lot about lead acid batteries, and I definitely don't know anything about your specific batteries.
But, here are a few things to consider.
  1. Victron is a reputable (and usually conservative) manufacturer. It seems unlikely that out of 8 profiles they don't have one suitable for AGM or Gel
  2. Looking at this chart and this chart 12V puts you in the 40-60% DOD range, I'm not sure how representative these charts are or if they reflect your batteries voltage curve or not.
  3. Your desire to have a healthy DOD that maximizes cycle life is a good thing, but at the same time, the best way to achieve this is a properly sized system where your usage does not deplete the batteries overnight, and your low voltage cutoff is a second layer of defense. So the LVD itself does not need to be set at the optimal discharge that you are targeting unless you expect it to cut loads frequently. Does this make sense? its late and I'm not sure I'm explaining this point clearly.


Am I using the right product?

Are there alternate settings (I doubt it)?
I don't own it, but I believe the Victron SBP (smart battery protect) has configurable parameters.

Alternatively, if you have already bought the standard BP, you can use the remote inputs on it to switch it with an external device if you have something else in your system that can signal it to switch off at 12.5 or whatever your desired voltage is.
 
Many solar controllers have load outputs that can be configured with low voltage cut off and in some cases programmable time periods where the output is active, this could be considered.
Although the various voltage charts for AGM batteries help to an extent, I suggest that using a 12.0 v limit would take into account variables in the system.

If a minimum of 4 hours use is needed, could a timer citcuit be introduced to only enable the system during the day, say after noon for 6 hours?

As alternative to voltage control for limits you could use state of charge. For example the Victron BMV 702 battery monitor could be programmed to use it's state of charge relay to disable the inverter. A quick look at your inverter specification does not suggest there is a remote enable which makes the interface more difficult but not impossible. Many alternative inverters have the remote enable facility.

Note that the Victron Battery Protect is not recommended for inverter loads, as its possible the inrush could damage the unit.

In conclusion, monitoring the battery state of charge is a far more precise method of protecting the battery than using voltage, however if voltage is used, a setting of 12.0 volts would seem suitable.

Mike
 
I just got the 100a version of Victrons battery protect and you can set low voltage cutoff to whatever you want via Bluetooth in the Victron connect app.
 
I just got the 100a version of Victrons battery protect and you can set low voltage cutoff to whatever you want via Bluetooth in the Victron connect app.

Yup, this @TheOx - that's exactly what I did in my system. I set the LVDC for my 48v system to 48v (3.0 vpc).
 
Don't use a battery protect on the inverter. It will fail.

You're right - I should have read the original post more thoroughly. You cannot use a BP to directly control an inverter. You CAN use its relay signal to direct the inverter to shut down, but do NOT connect the inverter DC input through the BP.
 
You're right - I should have read the original post more thoroughly. You cannot use a BP to directly control an inverter. You CAN use its relay signal to direct the inverter to shut down, but do NOT connect the inverter DC input through the BP.
Yeah, I didn't read that either, just saw the voltage limit issue. I'm using mine to disconnect power to my DC load block.
I know the smart battery protect is a "one way" device, so it wouldn't work with an inverter-charger, but what is the problem using it with one-way power flow to an inverter (assuming it's not also a charger)? I don't think the battery protect would have a problem with that, but maybe it's bad for the inverter to abruptly cut it's power source?
 
The first thing that stands out in the manual:

The short circuit protection of the BP will be activated if you try to directly connect loads with capacitors on their input (eg inverters). For that use case, please use the BP to control the remote on/off switch on the inverter, instead of disconnecting the higher power DC line
 
I'm not sure, I don't know a lot about lead acid batteries, and I definitely don't know anything about your specific batteries.
But, here are a few things to consider.
  1. Victron is a reputable (and usually conservative) manufacturer. It seems unlikely that out of 8 profiles they don't have one suitable for AGM or Gel
  2. Looking at this chart and this chart 12V puts you in the 40-60% DOD range, I'm not sure how representative these charts are or if they reflect your batteries voltage curve or not.
  3. Your desire to have a healthy DOD that maximizes cycle life is a good thing, but at the same time, the best way to achieve this is a properly sized system where your usage does not deplete the batteries overnight, and your low voltage cutoff is a second layer of defense. So the LVD itself does not need to be set at the optimal discharge that you are targeting unless you expect it to cut loads frequently. Does this make sense? its late and I'm not sure I'm explaining this point clearly.



I don't own it, but I believe the Victron SBP (smart battery protect) has configurable parameters.

Alternatively, if you have already bought the standard BP, you can use the remote inputs on it to switch it with an external device if you have something else in your system that can signal it to switch off at 12.5 or whatever your desired voltage is.
Hi @Dzl Thanks for your response. This makes absolute sense. I will look into it.
 
Don't use a battery protect on the inverter. It will fail.
I fully understand this.
Yeah, I didn't read that either, just saw the voltage limit issue. I'm using mine to disconnect power to my DC load block.
I know the smart battery protect is a "one way" device, so it wouldn't work with an inverter-charger, but what is the problem using it with one-way power flow to an inverter (assuming it's not also a charger)? I don't think the battery protect would have a problem with that, but maybe it's bad for the inverter to abruptly cut it's power source?
I am pretty sure that this is accurate. If you are using BP in both directions you need 2 BPs. It says below from Victron site that never use a BP for Charging.
https://www.victronenergy.com/uploa...A-100-A--220-A-EN-NL-FR-SV-DE-PT-ES-TR-IT.pdf 1610405863444.png
We have decided to add 2 more panels in the array and upgrade the controller and (there are 12 unused panels on the roof!!!???). This reduce the disconnect charge and we will work out you to patch in a charger when the generator kicks in on weekends for 3 hours in evening to fully cycle up the battery. The AGM battery is massive and brand-new and working really really well.
 
I just got the 100a version of Victrons battery protect and you can set low voltage cutoff to whatever you want via Bluetooth in the Victron connect app.
$20-$30 extra would have got the Smart version :( should have.
 
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