Hello,
I have been trying to figure out what settings i should use for these batteries; i have two of them for 24volts.
https://bigbattery.com/product/24v-a123-lfp-battery-box-w-bms-free-shipping/
I called big battery and they said:
Turn off equalization
turn off absorb; or set it as short of time as possible
float at 26.6 - 27.6v
Do these settings seem correct? That it should go directly to float?
Also, they said set the Bottom at 22V and the Top at 29.2 (I don't know exactly what this means; except probably that the charger should stop at 29.2 and kick on at 22V) - How do i set this on the classic 150? I don't see any setting that lets me set the bottom and top voltages?
Sorry total newbie here - but i am learning slowly:(
They might mean setting your minimum and maximum voltages on the Classic which you can do but it doesn't relate to starting and stopping charging.
Only the absorb voltage, absorb time, ending amps, float controls how the Classic charges.
A lot of it depends on the BMS that is used on the battery.
You probably want to find out if you need to set maximum charging amps on classic.
just took quick look at your link - 130 amps max charging so you should be okay
Lithiums take awhile to learn all the ins and outs with them. They just are not so forgiving to abuses like lead acid .
Go to first page of the forums and do search for lithiums to read all the past discussions on here . There are lots of thoughts - some better than others.
What you might want to find out from them is if there is an ending amp setting - ( provided you have whizbang on your classic installed ) Then you can set the absorb, and it will terminate on an ending amps current and then go to float. In Absorb it holds the voltage steady but varies the current to do that. But with Lithiums it will usually give all current needed in bulk and then quickly go to absorb and then to float when ending amps is used. You could also set Absorb to very short Absorb time if that is what they want you to do - so it would give all power available in bulk, then gets to absorb and doesn't stay there long and goes to float.
Larry
Did Big Battery say anything about battery temperature affecting any charge voltage ?
What they say sounds like what I would think.... No or low Absorb time.
This was common although evidently some lithium batteries like a longer absorb time for some reason.
I'm running 24V system.
2X 24/280AH packs & 2X 24V/175AH.
Each has a Chargery BMS8T-300 used with Chargery's DCC smart Solid State Contactor and one QNBBM-8S Active Balancer.
Configured into Common-Port config.
All Battery Packs have exactly the same length of 4/0 wire to the common DC BusBars.
All battery Packs have an MRBF Fuse (Bussman)
All battery cables right to from Batteries to Inverter are 4/0 Royal Excelene.
Midnite Classic 200 & Samlex EVO-4024 Inverter/Charger
Charging Config setup:
Charge is capped to 28.8V (3.60V per cell)
- Absorb is set to 28.8V fr 15 minutes.
- Float is set to 27.8V *
- Equalize OFF
Lo cutoff is 22.0V (2.75V per cell)
Hi cutoff is 29.0V (3.625V per cell)
Temp Compensation is OFF.
WizBangJr end amps is set to 5 and to use WizBang. I don't think that's right but try to get an official answer anywhere... good luck.
*FLOAT: I have float set this way because I am Off-Grid & Solar powered only, therefore my inverter is always on and it's lightest draw @ 18W keeps things nicely in check. I don't use it's Powersave mode as it's not practical for my application. Side Note, the Samlex are 95% Efficient, unlike many other inverter brands/models. FLOAT has to be carefully considered and set do that it is not continually topping the batteries. LFP does NOT like to sit at 100% SOC for long, in fact you can charge LFP to 3.65 all day long and stop and let settle for an hour, they will usually drop to 3.55V resting , so if you want to float them it's best to do so below that point, so I use 27.8V or 3.47V per cell.
EVO Profile is #3, 2-Stage-Type-1.
Very programmable & Lithium Friendly. Can accept Charge ON/OFF or Inverter ON/OFF signals for the correct type of BMS.
A CRITICAL GOTCHA !
All Lithium battery types are Voltage Sensitive ! You have to really make sure to Calibrate the voltages. If your battery bank says 25.0V, the SCC (Solar Controller) & Inverter will likely see a different voltage, slightly less is normal. You have to configure the correction so that when the SCC sees 25.0V that it is actually 25.0V at the battery terminals (or common DC Bus terminals.) A half volt or even 1 full volt off can result in unpleasantness and strange behaviours.
BigBattery BMS. That is where you set the Lo & Hi volt cutoffs, BE CAUTIOUS ! They use a couple of different models of BMS so you will have to ensure you have the right docs for the BMS and then you want to know the Cells Specs they used for that battery pack. Specs vary a bit by manufacturer and particular cell models as well.
REF LINKS:
Chargery BMS8T: https://www.chargerystore.com/index.php?route=product/category&path=20_26
Chargery DCC: https://www.chargerystore.com/index.php?route=product/category&path=62
*NB: This is the new site, they are just updating their cert, so an error may appear.
QNBBM-8S Active Balancer: https://deligreen.en.made-in-china.com/product/VszxkDEUbCce/China-8s-24V-Qnbbm-Lithium-Battery-Equalizer-Balancer-BMS-for-LiFePO4-Lto-Ncm-Lmo-18650-DIY-Pack.html
Royal® EXCELENE ® NON-UL WELDING CABLE: http://www.industrial.southwire.com/en/tile/10/spec/70305/
Samlex EVO-4024: https://samlexamerica.com/products/ProductDetail.aspx?pid=575
PS to MIDNITE SOLAR:
Seriously, it is time to come up with an updated Firmware to support Lithium directly. I know you are no longer enthusiastic about the Classics in favour of what you folks are cooking up for the future (whenever that is) but the Classic are Bread & Butter baseline products for you guys.... time to step up. Even writing an official addendum to the manuals from "The Midnite Company" related to configuring Classic for Lithium Battery Systems. When Chinese companies flogging $300 SCC's can do it, why can't you ?
Quote from: Steve_S on November 14, 2020, 10:09:08 AM
PS to MIDNITE SOLAR:
Seriously, it is time to come up with an updated Firmware to support Lithium directly. I know you are no longer enthusiastic about the Classics in favour of what you folks are cooking up for the future (whenever that is) but the Classic are Bread & Butter baseline products for you guys.... time to step up. Even writing an official addendum to the manuals from "The Midnite Company" related to configuring Classic for Lithium Battery Systems. When Chinese companies flogging $300 SCC's can do it, why can't you ?
http://www.midniteftp.com/support/kb/faq.php?cid=1
Thanks for that link.
Interesting that a New Member finds that and none of the "old timers: shared those links.
I posted a new message thread under Lithium (likely ought to be Stickied) with direct links to the Lithium Config posts in the tech support FAQ resource.
I also posted this info into the resource section at https://diysolarforum.com as a LOT of Midnite folks are there and most have the same questions / issues. There is also an ever increasing number of folks converting from Lead to LFP (LiFePO4) and they "need" the information.
It's quite obvious that many still think Lithium is crazy expensive like it was even two years ago... that depends on the chemistry obviously but also supply & demand... LFP does not have the same demand pressure for EV's and such and the advancement of the chemistry and increase in production has been extensive. LFP does not explode, catch fire or contain expensive nasties like Cobalt.
PSST: 16 Pcs 3.2V 280Ah Grade-A EVE LiFePO4 = Total $1,662.32 USD delivered DPP (Duty, Taxes & Fees paid) to North America. That makes ONE 48V/280AH/14.336 kWh battery pack, add a fuse, BMS & box/casing and voila.
Then there are companies like https://bigbattery.com/ in the US which are turning the battery sector upside down, if you don't want to build your own packs.
steve_s
my sentiments exactly. even die hard american anti lithium youtubers are turning to lifepo4 batteries.
and yes, i think midnite classic is missing the train.
my float settings are 3.35V
absorption 3.5V
faired well with those settings. more than 4 years. the midnite classic however even after adjusting Vbat, needs higher settings to comply with the desired settings. (so at stead of 56V absorption 3 classics are programmed to 56.1V and one to 56.2. 2 classics programmed to 53.8V, 2 classics 53.7V to get the desired actual 53.6 float voltage. all this does not greatly affect lead acid batteries i suspect. but with lifepo4's those thenths of volts are a large factor.
I run Samlex EV Inverter... hit an issue, had a quick chat with their engineering (not tech support guys ) and voila an updated firmware. * I have a developer NDA with Samlex for ModBus integration. A few BMS' makers I deal with have also taken suggestions and applied them and even developed new product as a result of those discussions. EVEN Victron has taken a few items and applied them once forwarded to them...
Are we seeing the boat sail off into the vast distances ?
I hope not.... I do really like my Classic-200 it's a Champ but, 5 years after the purchase, I'm hearing myself say "Should'
a Could'a, Would'a" more often now especially since my foray into LiFePO4.
Ohhh well... none of this is registering so it's pointless.
The new stuff about to hit the streets from Samlex has my eye (no public info released yet).
The other segment is the All-In-One systems such as MPP-Solar, GroWatt, AExpert and others are really taking off, especially since all the wildfires and other amplified events have pushed peopel to look at alternatives to Grid Power & Grid Power backup systems. The quality AIO Producers can't keep up production to satisfy demand.... Missed Opportunities are rarely if ever recoverable, especially for the lackadaisical. When people start looking at companies in this sector, most want to see an active company updating, adding new product in a timely fashion and staying "current" visibly, that is important... When I hear words like STALE, stuck in the past, not innovating when aimed at a company, that's the first warning flags being raised...
Midnite has said it is devoting their engineering efforts to their new line of inverters and I believe there are also some new controllers associated with those.
So it isn't like Midnite are just twiddling their thumbs doing nothing.
They have the Classic which is stable and reliable. Updates to firmware often carry unknown bugs that need a lot of field testing. The other option is to put their efforts into new controllers with new hardware and software that is more adaptable to the newer technologies.
For those of us who have been using Midnite products since their beginning we have seen a lot of innovation and requested upgrades in firmware. And also hardware - like the Whizbang which was an incredible inexpensive addition that gave so much more value and control options to both the Classic and the Kid.
You still see a lot of support on here for the Classic from Midnite.
It is nice that a company like Samlex is working with you. Do they also have a public forum that lets anyone ask technical questions, discuss bugs or grievances, and have the engineers and technicians from the company openly problem solve and participate ? If so what is the link ?
Larry
Steve, we have 22 engineers innovating right now so we're not stale... As you know, you can't do that and survive.
Samlex and Victron are good companies though and we actually work with both of them.
The Classic and Kid should work fine with most LiFePo battery systems. What problems are you having ?
After a little reading on here, it looks like my Midnite Classic is going to become an expensive boat anchor. I want to change to LiFePo4 batteries, and I don't see any really good, safe way to charge them with my Midnite Classic. Looks like I'll have to be moving to a Victron solar controller. I've had this charger for a while, but haven't had the chance to go camping with it. Stinking Trojan lead acid batteries are such a pain to keep water in, is why I'm switching. Oh well...
DAY8293A@CS.COM,
the midnite classic charges lithium battery totally perfectly and without danger of doing something wrong. unlike some of the cheap chinese products. and yes victron is a very close runner up. they do have settings for different battery types. though not as programmable as the midnite and many expensive gadgets needed to make victron work in tandem.
Quote from: DAY8293A@CS.COM on December 19, 2020, 01:48:01 PM
After a little reading on here, it looks like my Midnite Classic is going to become an expensive boat anchor. I want to change to LiFePo4 batteries, and I don't see any really good, safe way to charge them with my Midnite Classic. Looks like I'll have to be moving to a Victron solar controller. I've had this charger for a while, but haven't had the chance to go camping with it. Stinking Trojan lead acid batteries are such a pain to keep water in, is why I'm switching. Oh well...
What are you trying to charge? Classic can be set to nearly any oddball voltage and time combo you care to figure out
Bulk and Absorb to 23V, Absorb time to 5 min, Float to 22V ? Whatever you need, you program into it.
The Classic charges Li batteries just fine. You will have to set it properly to work with your batteries.
If your Li battery's BMS has an output to tell the charge controller that it is charged, the Classic's AUX2 has an input that is just for that function.
If you want your Li battery to communicate with the Classic directly over MODBUS, then just set its BMS to give the Classic the proper commands.
What does your lithium battery management system need to do in order to charge properly ?
If there is some other communications interface, then a $40 Raspberi Pi might be necessary to interpret for each other.
Quote from: DAY8293A@CS.COM on December 19, 2020, 01:48:01 PM
After a little reading on here, it looks like my Midnite Classic is going to become an expensive boat anchor. I want to change to LiFePo4 batteries, and I don't see any really good, safe way to charge them with my Midnite Classic. Looks like I'll have to be moving to a Victron solar controller. I've had this charger for a while, but haven't had the chance to go camping with it. Stinking Trojan lead acid batteries are such a pain to keep water in, is why I'm switching. Oh well...
Have a Look at this:
CLASSIC - LITHIUM Quick Starthttp://www.midniteftp.com/support/kb/faq.php?id=121
CLASSIC - LITHIUM - How do I set the Classic to charge Lithium batteries (explained)?http://www.midniteftp.com/support/kb/faq.php?id=75
How do I set the KID to charge Lithium batteries?http://www.midniteftp.com/support/kb/faq.php?id=87
If you have a WizBang, the SOC readings etc are "subject to interpretation" as it's geared for Lead voltage profiles ?
Lithium Chemistry Voltage Curves vary a lot so this is a PITA simply put.
If you have multiple battery packs in a Bank, each with a BMS, interacting with the multiple BMS' becomes a bit of a dance as no single BMS can interact with the SCC, an intermediary has to arbitrate between the gear. Master / Slave decentralized BMS' can do such, using a programmed Raspberry/Arduino or similar may also serve such a function.
REC-BMS: http://www.rec-bms.com/BMSSMA.html *Not Cheap: You get what you pay for.
123-Smart-BMS: https://123electric.eu/
Batrium BMS: https://www.batrium.com/collections
It would be nice if the WizBangJr had voltage profiles for different chemistries.
There are 3rd Party monitors which can provide more accurate SOC. Several Models below, some with Shunts, others with Pickups. *Search part number on Amazon/EBay, several vendors carry them.
https://peacefair.en.made-in-china.com/product-group/yeKnbFSoPrWd/DC-Electric-Energy-meter-catalog-1.html
Quote from: Steve_S on December 20, 2020, 04:04:42 AM
It would be nice if the WizBangJr had voltage profiles for different chemistries.
There are 3rd Party monitors which can provide more accurate SOC. Several Models below, some with Shunts, others with Pickups. *Search part number on Amazon/EBay, several vendors carry them.
https://peacefair.en.made-in-china.com/product-group/yeKnbFSoPrWd/DC-Electric-Energy-meter-catalog-1.html
Steve ,
I don't get what you mean by the SOC not working for different battery types ?
The Whizbang is just counting amps in and out and voltage doesn't matter to it right - so what would be different ?
Larry
Quote from: boB on December 19, 2020, 11:19:19 PM
The Classic charges Li batteries just fine. You will have to set it properly to work with your batteries.
If your Li battery's BMS has an output to tell the charge controller that it is charged, the Classic's AUX2 has an input that is just for that function.
Gonna use AUX2 this way - does anyone know the impedance?
And is it safe to use 24 volts?
Quote from: Bob D on December 20, 2020, 10:15:29 PM
Quote from: boB on December 19, 2020, 11:19:19 PM
The Classic charges Li batteries just fine. You will have to set it properly to work with your batteries.
If your Li battery's BMS has an output to tell the charge controller that it is charged, the Classic's AUX2 has an input that is just for that function.
Gonna use AUX2 this way - does anyone know the impedance?
And is it safe to use 24 volts?
Well, Aux 2 input it designed to work up to around 17 or 18V as I remember. It is 10K Ohms into a 3V Zener inside.
But recalculating, that 10K Ohms hits a 3V Zener so at say, 25V input to Aux 2, that would be I = (25V-3V) / 10K = 2.2 mA
The resistor is a SMD and would have to dissipate around 2.2mA X 22V = 48 mW.
I would add another 10K Ohms maybe just to play it safe. The input threshold for a high or a "1" is around 5V as I remember but might be lower actually.
Here is a chart for LiFePO4, other chemistries are different
WizBang is reporting 26.3V at 96% but that is 3.287 per cell.
Well, Aux 2 input it designed to work up to around 17 or 18V as I remember. It is 10K Ohms into a 3V Zener inside.
But recalculating, that 10K Ohms hits a 3V Zener so at say, 25V input to Aux 2, that would be I = (25V-3V) / 10K = 2.2 mA
The resistor is a SMD and would have to dissipate around 2.2mA X 22V = 48 mW.
I would add another 10K Ohms maybe just to play it safe. The input threshold for a high or a "1" is around 5V as I remember but might be lower actually.
[/quote]
Given that the 24 volts is nominal and will be somewhat higher, it is probably best to use a lower voltage.
Picking 12 volts, and using your calc, the input would be 0.9ma. If I put a 10K and 40K resistor in series, and grounded the 40K, there would be 12V at the junction, assuming the 0.9 ma is correct. This setup also has the benefit of pulling AUX to ground when the 24V is removed.
Since the calcs might not be accurate, using a couple of 50K trm pots would allow tuning at setup.
Does this make sense?
steve_s
voltages on a lifepo4 to figure SOC does not mean very much. unless you want to stop drawing power and let the battery settle in for an hour or so.
also 3.65V is rather on the destructive end. 3.5V is now the generally accepted charging V. and keep in mind when charging towards the end some cells might be higher than others.
Quote from: Steve_S on December 21, 2020, 03:28:36 AM
Here is a chart for LiFePO4, other chemistries are different
WizBang is reporting 26.3V at 96% but that is 3.287 per cell.
The Classic with Whizbang does not calculate SOC based on voltage. It does it based on how many amps go in and out of the battery compared to what was programmed in for the batteries total AH capacity .
Larry
Here is a video with the Classic and Lithium batteries...
https://youtu.be/YsE1JPGg7Co
Vic,
No lighting strikes recently and you are correct I am in the Caribbean, Barbados to be precise. I have another classic workinig just fine at the same location. The classic shows around 41v when no input breaker is off.
Thanks