Can Classic+WBJr trigger events based on Ah in/out of battery bank?

[openplanet]

Thank you boB.
If the people you chat with need to chat with someone who can make a compelling, air-tight, overwhelming, stupendous, powerful, stunning, powerful case for these two enhancements, send 'em over to me and I'll work my persuasive magic.  Oh, and did I mention that with these two enhancements sales of Classics will spike by at least 20%?  Yup...
--Paul, aka Openplanet

[openplanet]

Fair enough boB...but what about Net WbJr. Ah? As I tried in my last post to make the case, this alone would go a huge way toward enabling LiFePO4 owners to charge and discharge their battery banks in a way that protects them very effectively.
Can we hope for a firmware change that would let us toggle Aux outputs based on + and - Net Ah set points???

[Steve_S]

Been a while to get back to this thread.

Classic to LifePo issues.  Not including the self-contained LFP packs which have their own internal BMS.
A Smarter BMS with the ability to communicate like http://chargery.com/BMS8T.asp or https://www.energusps.com/shop/product/tiny-bms-s516-150a-750a-36?category=4 as an example of TWO but there are many more is increasingly common, in addition to Separate Port BMS' which have an independent charging circuit aside from the load terminal.

Typical conditions to monitor for are:
- Hi & Lo temp to prevent charging in harmful conditions.  Never charge below freezing or in over heat conditions.
- Hi & Lo voltage disconnect.  Pretty obvious why, very voltage sensitive.

---   An AUX port being able to receive the ON/OF signalling from a BMS would save a LOT of hackery that is potentially more weak points in a system.  more pieces subject to failure....
---  A simple 2 Stage Charging Profile to accommodate newer battery tech like LFP & LiIon.  No need for Equalization...

boB
Yeah, you won't be seeing battery voltage sense on a Classic but the new stuff has it.

??   New Stuff ?   Abandoning the Classic line or   Maybe time to get the pre-warranty end refresh of my C-200 if that's still going...   Or is that like the free WizBangJr deal which never arrived ? 

----   From Samlex:  The Inverter I use, on their BMS interaction / capability.  ------------------------------------

3.16 INSTALLING CONTROL INPUT WIRING FROM LITHIUM BATTERY MANAGEMENT SYSTEM (BMS) TO ENABLE / DISABLE CHARGING OR INVERTING Refer to Section 5.11.2 regarding “Stop Charging” or “Stop Inverting” protections for Lithium Ion Batteries when parameter “BATTERY TYPE” is programmed for Option 2 - “1=Lithium” (See programming details at Section 4.4.2.22.2 in the EVO-RC Manual attached at Appendix A)

The Battery Charger Section of EVO is designed to charge 3 types of batteries - Lead Acid / Nickel Zinc (Ni-Zn) / Lithium Ion. Lead Acid and Nickel Zinc (Ni-Zn) battery charging voltages are required to be compensated based on the temperature of the battery cells. Hence, Battery Temperature Sensor Model EVO-BCTS is required to be connected to the RJ-45 Jack (6, Fig 2.1) as explained at Section 3.15.

Charging voltages of Lithium Ion Battery are not affected by temperature and hence, Battery Temperature Sensor Model EVO-BCTS is NOT required to be used when Lithium Ion batteries are used. The RJ-45 Jack (6, Fig 2.1) can be used to feed control signals from certain Lithium Ion Battery Management Systems (BMS) that may have capability of enabling / disabling “Stop Charging” or “Stop Inverting” control signals for inverter chargers. This control signal is normally generated by the BMS by switching ON (enabling) or switching OFF (disabling) potential free, Drain (+) and Source (-) terminals of mini Opto Isolated Mosfet Switch [Solid-State Relay (SSR)]. Connect the control signal output from the BMS to RJ-45 Jack (6, Fig 2.1) as follows:
• BMS control signal terminal marked “+”: o Connect to any of Pins 1/2/3/4 (Refer to Fig 3.13 for pinout of RJ-45 Jack. Pins 1 to 4 are internally shorted) • BMS control signal terminal marked “-”: o Connect to any of Pins 5/6/7/8 (Refer to Fig 3.13 for pinout of RJ-45 Jack. Pins 5 to 8 internally shorted)
-------------------------------------------------------

[boB]

Been a while to get back to this thread.

Classic to LifePo issues.  Not including the self-contained LFP packs which have their own internal BMS.
A Smarter BMS with the ability to communicate like http://chargery.com/BMS8T.asp or https://www.energusps.com/shop/product/tiny-bms-s516-150a-750a-36?category=4 as an example of TWO but there are many more is increasingly common, in addition to Separate Port BMS' which have an independent charging circuit aside from the load terminal.

Not familiar with these but may have a look.  The guys working on the LiFePo batteries should definitely see those if they haven't already.

Typical conditions to monitor for are:
- Hi & Lo temp to prevent charging in harmful conditions.  Never charge below freezing or in over heat conditions.
- Hi & Lo voltage disconnect.  Pretty obvious why, very voltage sensitive.

There is a high temp turn-off already in the Classic but you might have to call tech support to find out how to change it. It involves getting into the modbus editor in the MNGP and changing one of the registers is all.

Low temp and Low voltage disconnect ?  Not sure how important that is unless there is something really wrong with the batteries ?  I might be brain dead right now and forgetting something important ?  At low temperature, charging should heat the batteries up and low voltage should charge them up.

---   An AUX port being able to receive the ON/OF signalling from a BMS would save a LOT of hackery that is potentially more weak points in a system.  more pieces subject to failure....
---  A simple 2 Stage Charging Profile to accommodate newer battery tech like LFP & LiIon.  No need for Equalization...

Aux 2 can be programmed to turn on and off with a high or low logic signal.  This mode was added to the Classic just for lithium BMS's actually.  Can't remember who ?

boB
Yeah, you won't be seeing battery voltage sense on a Classic but the new stuff has it.

??   New Stuff ?   Abandoning the Classic line or   Maybe time to get the pre-warranty end refresh of my C-200 if that's still going...   Or is that like the free WizBangJr deal which never arrived ? 

No, not abandoning the Classics.  It'll be a little while before  new CCs are out though.


Will have to see what the others have been doing.  We have others around here that know way more than I do about this stuff anymore !

----   From Samlex:  The Inverter I use, on their BMS interaction / capability.  ------------------------------------

3.16 INSTALLING CONTROL INPUT WIRING FROM LITHIUM BATTERY MANAGEMENT SYSTEM (BMS) TO ENABLE / DISABLE CHARGING OR INVERTING Refer to Section 5.11.2 regarding “Stop Charging” or “Stop Inverting” protections for Lithium Ion Batteries when parameter “BATTERY TYPE” is programmed for Option 2 - “1=Lithium” (See programming details at Section 4.4.2.22.2 in the EVO-RC Manual attached at Appendix A)

The Battery Charger Section of EVO is designed to charge 3 types of batteries - Lead Acid / Nickel Zinc (Ni-Zn) / Lithium Ion. Lead Acid and Nickel Zinc (Ni-Zn) battery charging voltages are required to be compensated based on the temperature of the battery cells. Hence, Battery Temperature Sensor Model EVO-BCTS is required to be connected to the RJ-45 Jack (6, Fig 2.1) as explained at Section 3.15.

Charging voltages of Lithium Ion Battery are not affected by temperature and hence, Battery Temperature Sensor Model EVO-BCTS is NOT required to be used when Lithium Ion batteries are used. The RJ-45 Jack (6, Fig 2.1) can be used to feed control signals from certain Lithium Ion Battery Management Systems (BMS) that may have capability of enabling / disabling “Stop Charging” or “Stop Inverting” control signals for inverter chargers. This control signal is normally generated by the BMS by switching ON (enabling) or switching OFF (disabling) potential free, Drain (+) and Source (-) terminals of mini Opto Isolated Mosfet Switch [Solid-State Relay (SSR)]. Connect the control signal output from the BMS to RJ-45 Jack (6, Fig 2.1) as follows:
• BMS control signal terminal marked “+”: o Connect to any of Pins 1/2/3/4 (Refer to Fig 3.13 for pinout of RJ-45 Jack. Pins 1 to 4 are internally shorted) • BMS control signal terminal marked “-”: o Connect to any of Pins 5/6/7/8 (Refer to Fig 3.13 for pinout of RJ-45 Jack. Pins 5 to 8 internally shorted)
-------------------------------------------------------

[mike90045]

  .....  Low temp and Low voltage disconnect ?  Not sure how important that is unless there is something really wrong with the batteries ?  I might be brain dead right now and forgetting something important ?  At low temperature, charging should heat the batteries up and low voltage should charge them up.

Below 40F, Li batteries become less capable (charging & discharging) and below 33F unable to be safely charged. 
Since their internal resistance is so low, there is very little self-heating, and off-grid usage doesnt usually charge/discharge hard enough to get them very warm, just a couple degrees above ambient.

Even here is NoCalif, winters get to 15F at 1500' elevation.  A couple days of that and my NiFe bank is hovering around 32F, and I get condensation  frost on my generator in the pole barn.  I have to run 5-30 weight in the diesel to get it cranked, otherwise I can't spin it fast enough to start.   

If I went to Li batteries they would be below 32 unless I had heaters on them.  I use kerosene lamps in the pumphouse and greenhouse to keep the temps above freezing.  So having a simple software tweak to inhibit charging below 33F would be beneficial immediately and solve the issue of the BMS disconnecting the batteries from the controller when cold

[Steve_S]

Charging below freezing 32F/0C with cannot be done without damage as Mike said. I'm in Northern Canada, -30 happens here and IF there is a heat failure in my powerhouse...  safeties are important.  Info on this forum and the main docs are minimal & what can be found not very helpful.   The world moved beyond FLA

BTW:  I promote the Classic as well as my Samlex Inverter because it is good gear and does what it should but without good documented features / functions that support LFP & LiIon & BMS interactivity it limits the potential....    Maybe it would be wise to pay attention to Victron & Others to see where they are a and how they are supporting LFP etc.  Even an addendum that specifically addresses LFP & Lithium Variants and the settings etc (at minimum) for now woudl be better than what's available now... 

@Mike:  I use a propane furnace recovered out of a wrecked RV Camper... to keep my powerhouse  / pumphouse warmed up, it's a  Suburban brand, with a 12V & LPG, I have it running with the dual regulators, and a 12V battery attached to it's own Solar Charger to keep it independent.  Quite convenient and much less fussy and without a pilot light, (electronic ignition) it works a treat.

[Westbranch]

Hi Steve, Just where are you  north of the 49* Latitude? 
I am in the Cariboo in BC.  I like your use of a RV heater.  How much insulation do you have (R value wise) and have you been successful at -40* ?

PS  there was a post in your other thread  I believe  from a fellow at either CorMax or CMXbattery.com.
I went to their site and  saw an interesting picture of  their BMS...  you might want to see if it does what you want.
I also have been discussing with  a rep about a 500 Ah 24V unit..  LiFePO4 and they have addressed every question so far...

[Steve_S]

I'm near to CFB Petawawa (Algonquin Park) Ontario.   Deep in the valley & up the line !

Powerhouse:   the Powerhouse / Pumphouse 75' from cabin. It is heated via a small RV Furnace which I got from a wreck with electronic ignition, runs with 12VDC and has it's own AGM & Solar Panel with charger just for it. That building is also hyper insulated with 4" thick XPS between the studs (locally milled and really 2x4 not 1.5" x 3.5") and then 1" of XPS before exterior sheathing & cladding, it also has a frost protected slab foundation with radiant pex in it (for future).  Th roof has 6" of PolyISO between the rafters and a cool roof system over it.  The 1" creates a thermal break increasing R value.   The XPS is R5 per inch, the ISO is R6 per inch.  I keep the powerhouse at 10C because it also holds my 50 Gallon pressure tank & well head.

I bought a Chargery BMS8T with 2 300A relays and the relay delay board as well.   This will allow me to hookup my RaspberryPi with NodeRed etc to communicate with the BMS as well as the Classic 200 & the Samlex EVO Inverter using Modbus.   There is a thread on that.

[boB]

OK on the low temperature cut-off for lithium.  Like I said, I wasn't the expert.

It would seem to me that the BMS in lithium batteries should also take care of this issue but I guess that BMS's have a little ways to go yet.

So, is it unsafe to discharge them below freezing as well as charge them below freezing ?

[Steve_S]

You can discharge below freezing but not charge below freezing.   BMS do handle Hi Temp, not all handle low temp or have low temp cutoff.   The cutoff occurs @ the Battery / BMS meaning that is basically leaves a relay OPEN so the charge controller is feeding power to nothing !  (battery is essentially disconnected).   SOME BMS' can & do use external relays which are in-line with the battery cable to disconnect the battery if triggered.  -

In some cases, to disconnect solar charging, people are dropping the Solar Panel IN line before the charge controller.  As well as other assorted means.   

There are different types of BMS' with features & functions relative to their target market.  Some are for E-Bikes and fairly basic, others for EV's are quite complex (as you all learned) then those for Energy Storage again are different with various features & functions.   The "Basics" like charging profiles for LiIOn and LiFEpo4 (they are different), Hi / Lo Volt, Hi / Lo Temp need to be observed.  for SOC / DOD measurements, very accurate voltage readings need to be monitored as well, there is very little "grace" there, unlike FLA and variants.  An extra volt over full charge on FLA won't bother it but could be a problem for LFP / LiIon because often the DOD is user limited to 80/20.  Meaning 80% full to 20% remaining and they operate their battery pack between those % for DOD to extend / prolong the lifespan of their batteries.

[boB]

Yeah, the different chemistry or "alloys" maybe they should be called for lithium have different requirements for sure.

As for the relay being open (FETs usually these days), the BMS can tell when it is being charged or discharged so maybe that should be included ?   

What they could do to help this maybe is to let the current go slightly into charge and for a certain amount of time (seconds or minutes) and THEN shut off the relay FETs for some amount of time and then turn them back on again.
This can be tailored to any lithium chemistry as needed.

[mike90045]

The problem is, charge rate needs to be about c/100 at cold temps, so really, not worth charging at all. simpler to just not charge

The BMS preserves the battery when activated, by cutting the power lead, and now the charge controller has 103V of PV on it's input, and no battery connected. 

So really, the Charge Controller needs the BTS to be able to inhibit charging below 33F   
  Couldn't this be a new menu item in the classic firmware, if BTS <33F , go to Resting mode ?  Maybe in the temp comp selection menu ?

[ClassicCrazy]

Does anyone know how Tesla deals with charging their car batteries when they are below freezing ? Do they have some resistance heating coils in the battery bank ? Or do they do a slow charge to gradually warm them up enough above freezing ?

Larry

[Steve_S]

There is a heating element in the coolant lines,

[australsolarier]

i feel too midnite classic missed the bus on lifepo4/lithium ion batteries. maybe it is just american conservatism. but it seems to me lead acid will soon be a thing of the past.
it seems to me midnite classic never much experimented with lifepo4 batteries. the experimenting was all done by users.
it seems to me midnite classic sort of abandoned the classic chargers for new things that seem not to appear anytime soon.
would have been better working with a reliable inverter manufacturer. (or bms manufacturer)
just saying