PLEASE NOTE: If you had an account with the previous forum, it has been ported to the new Genetry website!
You will need to reset the password to access the new forum. Click Log In → Forgot Password → enter your username or forum email address → click Email Reset Link.
5.3 Switched trigger circuits: above 50mA If your devices are on/off triggered, and the total switching current needed on one EXTIO port is above 50mA, then you will need a relay — ideally, an optically-isolated solid-state relay (SSR). Here are some examples to choose from: • The SSR-25DD and DC60S5 are panel-mounted options. They’re overkill for most applications, but easy to use. • The CPC1706 is a good choice for many circuits, and has a maximum load current of 4A, but it needs to be soldered into perfboard or other circuit board. If you need to reverse the on/off signal, which is common for EXTIO Type 3, 4, & 5, you can use the CPC1705 or other normally-closed SSR. • The 817 optocoupler board, available on Amazon, is popular, but not particularly high-quality. Remove the red jumpers if you use it. In order to power the relay, you’ll need to connect the EXTIO+ through a resistor to your positive distribution busbar, and the EXTIO− to the SSR input positive. Then connect the SSR input negative to your negative busbar. Your device(s) can now be switched by the SSR load terminals. You can also add more than one SSR in parallel on a single EXTIO as long as the total draw is under 50mA. The size of the resistor depends on the minimum switching current that’s required by the SSR. For example, a CPC1706 requires 5mA to activate, so for a 24V battery, the resistor can be a maximum of 24V ÷ 0.005A = 4,800 . Ω To give a safety margin, you may want to size it around 3,000 . Then to check the power rating for the resistor, V Ω 2 /R = 242 ÷ 3000 0.2W, so with a ≈ healthy safety margin, a 0.5W resistor will work well.
Electrical rules still apply regardless of what ideas might be tossed around. The options above that cannot be used on 48v systems are...well...all but one of them:
- PC817 cannot be used (I've mentioned this at LEAST once above): 35v breakdown voltage
- CPC1705 / CPC1706 / DC60S5 really can't be used either: they all have a 60v breakdown voltage. This MIGHT work, but you're playing with trouble when the system voltage can easily reach 56-58v on LFP. (Guaranteed failure if you're running lead-acid, which can easily reach 64-65v.)
- SSR-25DD has a ~240v DC rating, so the switching side is good.
Worth noting that ALL of these have an absolute maximum input signal rating of 32v or less--so the mentioned resistor divider will have to be experimented with and set to a value that ensures the input signal voltage rating is not exceeded.
Worth noting that ALL of these have an absolute maximum input signal rating of 32v or less--so the mentioned resistor divider will have to be experimented with and set to a value that ensures the input signal voltage rating is not exceeded.
I do not have any 24v inverter so I will use my 12v Powerjack . Thank you for the warning .
PowerJack 24-volt inverter automatic control: >>>>this is in reference to controlling the 24-volt PowerJack LF PSW SP Inverter at the moment (at the cell level monitoring the Electrodacus SBMS0 can provide that the PowerJack can not adequately do for a LiFePO4 Battery)..I am starting to understand more of the terminology...
the gross battery voltage (SOC) that PowerJack uses to turn the inverter off will be an early death wish(to a LiFePO4 battery) if something goes haywire with an individual cell or connection within the LiFePO4 battery builds....
this can later be designed for the 48-volt LiFePO4 i think with the right components...
yes, yes, I know the Electrodacus SBMS0 only works for up to 8S 24-volt configurations,,,it can work with 12 volts (and is designed to do so) and also and many different battery chemistries.... but I am currently concentrating on the LiFePO4 protection and control via the SBMS0....
I will start with controlling the 24-volt PowerJack inverters as the learning guiney pigs, likely a 6000 watt 24-volt one 1st as it was the least expensive.
the optoisolator in the relay will add a second layer of isolation ...
i do not want to damage the SBMS0 so i will use a separate power supply. the inflation is also driving up the price of the SBMS0... >>>i know why the arduino uno was not needed. i can get the second voltage with a buck converter attached to the battery...>>>> I may be able to utilize the arduino uno some other place later....
use the SSR relay with the jumper removed... that will make it so the one side uses mA from the SBMS0 and the other side uses the voltage from a separate power source, as i am starting to understand it more...
still learning the relay lingo so forgive the newbee(me) to the SSR (solid state relay)
learning more on youtube videos....
thanks for all your help and patience!! 😒🤔😎
more later
PowerJack 24volt inverter shut down automation: progress hopefully
Yesterday 4/4/2022 I ordered two of the >>>>
HiLetgo 2pcs DC 24V 1 Channel Relay Module with OPTO Isolation Support High or Low Level Triggle
from Amazon for $7.20 including tax and delivery
the idea is to use a buck converter as the power supply @24-volt..
the Electrodacus SBMS0 will give the signal to the optoisolator to turn off the inverter via the splice into the switch wire of the PowerJack 24-volt inverter. this will be done by the Electrodacus SBMS0 when any cell gets down to 2.5 volts so effectively stopping the over discharge from the PowerJack 24-volt inverter and saving the expensive LiFePO4 battery bank from over discharge damage. the cells in the series connected battery will then be protected at the cell level...
the gross voltage SOC (state of charge)that PowerJack inverters use to turn off the inverter in case of low voltage from the battery is inadequate to protect the expensive LiFePO4 battery...
i actually have 96 LiFePO4 cells cycling daily so it is a very big part of the solar off-grid equation / solution... the cell cost actually slightly over $10,000 dollars as i previously for some reason thought they were only 8000... >>>>32 272AH cells cost $2900; another 32 272Ah cells cost $3000 and the last 32 280Ah cells cost $4200 delivered and a bit more plus 2/0 wiring and tinned plated copper cable lug ends so maybe $10,300 ballpark investment to assemble 96 cells in the past 2 years... they became more expensive in year 2021 vs year 2020 prices(maybe worse today)
this is why the ability to stop or automatically turn off the PowerJack inverter is essential to my use... I am using the Electrodacus SBMS0 at 24-volts and I have 2 batteries in a 2P8S configuration and an additional 2 batteries in a 4P8S configuration. each is being charged with Electrodacus DSSR20's which are digital solid state relays capable of controlling up to 25amps each ( I have 2 250watt 60 cell solar panels connected to each Electrodacus DSSR20 so they usually push about 16-18 amps in parallel). the solar panels are connected in pairs in parallel at the array with Temco mc4 branch connectors.
this reliably charges the LiFePO4 batteries with no problems what-so-ever and the Electrodacus SBMS0 turns off the Electrodacus DSSR20's when any cell gets up to 3.55 volts for a preset time protecting the LiFePO4 battery from over charging... i have this part functioning correctly on the 4 assembled LioFePO4 batteries...
but i need to get the automated control of the PowerJack done via the Electrodacus SBMS0....via the ext io on the Electrodacus SBMS0....
i will set it up in a circuit and send pics when a few more parts are organized.... slowly ,,, very slowly!!!!
the Electrodacus SBMS0 will work with series connected batteries up to 8S configuration, so up to 24 volts and will also work great for 4S configuration or 12volt set ups in several different battery chemistries... I am using LiFePO4 cells
two steps forward - one step backwards???
have a great day all.... the darn wind is howling again in the night and this morning still...😒🤔😎
relay with smd optoisolator:
the 24v hiletgo relay...had to take a picture, could not copy and paste the product description...so a picture via the android cell phone of the desktop computer screen,,, not always very good quality... hope you can read it...
this is what i ordered from Amazon yesterday...
picture below
powerjack 24volt automation control progress: more info
Electrodacus SBMSO user manual that oberon compiled:
it does not copy and paste well for me, but it indicates that the extio 3 is used to control the loads and the optically isolated extio 3 max is 50mA at 300 volts. the way i read it is that when connected correctly to the inverter switch wire when any cell gets to 2.5 volts it will turn off as 2.5 volts in any cell is the point of the battery being out of the normal limits. still tyring to get my wiring correct for this part.
the extio 3 is on when the load is within normal cell voltage for any cell...
text copied and pasted from oberon's beginners manual for sbms0 below:
12 System specs quick-reference 12.1 Voltage & current limits Max Voltage Max Current Battery 32V 750A SBMS0 EXTIO ports 300V 50mA SBMS0 ADC2 & ADC3 60V — DSSR20 solar in 51V open circuit 20A DSSR20 Batt signal 30V 4mA (limited by 7k internal resistor) Ω DSSR20 Heat signal 30V 10mA 12.2EXTIO types All the EXTIO types are normally-open. A circuit connected to them is ON while everything is within normal limits, and they turn OFF if an out-of-limits condition is met. This is a fault-safe setup, as a charger or load will not turn on if a control wire is cut or the SBMS0 loses power. Type Function State & Trigger 0 Off Always off regardless of conditions 1 Charging disconnect Off if battery voltage rises above ‘Over Voltage’ setting 2 Load disconnect Off if battery voltage falls below ‘Under Voltage’ setting 3 High voltage alarm Off if SOC rises to equal or above ‘EXTIO SOC’ setting 4 Low voltage alarm Off if SOC falls to equal or below ‘EXTIO SOC’ setting 5 Fault condition Off if battery voltage goes outside of ‘Voltage Lock’ limit settings 6 Charging disconnect for dual solar array On or off to keep charge current within ‘Max PVOUT Current’, set in DMPPT settings. Works in conjunction with a Type 1 EXTIO to maintain optimum charging current with a dual array. The Type 6 EXTIO should control the larger (ideally 2×) array
the 4 different color wires represent the cat 6 solid core 24awg wire pairs( each color represents a twisted pair) purple is utilized for extio 3 for the load control automation. see pic below...
the extio 3 for load control is connected to >>>>actually it is the blue and blue white twisted pair... in some pictures it looks like a purple color for the twisted pair... sorry for any confusion.. i try to stay with a similar color coding when connecting all of the twisted cat 6 solid strand 24awg sense wires pairs to the sbms0...as best i can.
this can later be designed for the 48-volt LiFePO4 i think with the right components.
Two 24v batteries in series for 48v and 2 SBMS0 with one connected to each 24v will work for 48v inverter .
<a href="/monthly_2022_04/1787166911_Screenshot(363029).png.8e8e9dfdd907088ffa10e3cf30aaba9e.png" class="ipsAttachLink ipsAttachLink_image"><img data-fileid="1277" src="//forums.genetrysolar.com/applications/core/interface/js/spacer.png" data-src="/monthly_2022_04/913496935_Screenshot(363029).thumb.png.aa50900a81f7e970898157764624e6ea.png" data-ratio="56.1" width="1000" class="ipsImage ipsImage_thumbnailed" alt="Screenshot (363029).png">
<a href="/monthly_2022_04/1199056664_Screenshot(363033).png.1d43ac4bd3195f64114f147b986a032a.png" class="ipsAttachLink ipsAttachLink_image"><img data-fileid="1278" src="//forums.genetrysolar.com/applications/core/interface/js/spacer.png" data-src="/monthly_2022_04/1519576441_Screenshot(363033).thumb.png.1e4ba9f47c3a57274a0e154eec3c7754.png" data-ratio="56.1" width="1000" class="ipsImage ipsImage_thumbnailed" alt="Screenshot (363033).png">
10 hours ago, dickson said:Two 24v batteries in series for 48v and 2 SBMS0 with one connected to each 24v will work for 48v inverter .
this is the general direction i was heading. the SBMS0 is one of the better BMS's in my opinion; but does have a fairly steep learning curve.
i believe the SBMS0 can turn off more than one inverter at the same time, when correctly connected via the EXT IO number 3....
i could connect two of the 2P8S 24 volt batteries together or two of the 4P8S 24 volt batteries together, with each one being balanced by their own SBMS0.
the relays should be here in a couple days.... ordered bought some breadboards and some connectors to try assembly first as still a little uncertain in the connections....
i will try to show in pictures and some diagrams as i do more.......very very slowly....
i have bottle lambs taking more of my time and other critters plus family demands etc often seem to slow the progress....
thanks for your replies!😎
the automated turning off of the inverter is a must have so when one travels it does not require your physically turning off of the inverter... to save the high priced LiFePO4 battery bank. ((((a fail safe in case one cell goes haywire))))🤔
PowerJack inverter automated shut down:
coincidentally, i have been in a conversation with a online person who had cell number 15 go down to .2 volts in a Daly brand BMS controlled 16S LifePO4 battery. (possibly a bad cell, possibly a bad connection, possibly a faulty Daly brand BMS -- who knows for sure --- i am waiting for more info from the online person)
the SBMS0 would turn off the inverter if correctly wired when any cell drops to 2.5 volts,,, at least that is the direction i am trying to get to...using the Electrodacus SBMS0 to do so....
the gross voltage SOC (state of charge) that PowerJack inverters use to turn off their inverters will not adequately protect your expensive LiFePO4 battery if one cell goes south for some unknown reason....😒
2 hours ago, pilgrimvalley said:coincidentally, i have been in a conversation with a online person who had cell number 15 go down to .2 volts in a Daly brand BMS controlled 16S LifePO4 battery. (possibly a bad cell, possibly a bad connection, possibly a faulty Daly brand BMS -- who knows for sure --- i am waiting for more info from the online person)
Wouldn't be surprised if this was caused by inadequate balance current on the Daly. Pretty much all of the Chinese BMS options have pathetically small balance currents (usually 50mA, 0.05A). This would be adequate for a small battery bank (<100Ah), but most off-grid systems are considerably bigger than that.
Adding insult to injury with LFP is that it's only possible to balance cells when they near 100% SOC--because otherwise, their voltage is ~3.4vpc regardless of the SOC from 20-80% (or is it 15-95%?) That coupled with a paltry 0.05A balance current--means that said BMS units' balance capability is basically useless.
And if you're doing huge DOD (depth of discharge) cycles on a daily basis, that only increases the problem by several magnitudes.
Regardless, seems the Daly didn't disconnect @ 2.5v on the low cell...it'd only get down to 0.2v if the cell was completely destroyed due to overcharging (resulting from inadequate balance current), or overdischarged.
2 hours ago, pilgrimvalley said:i believe the SBMS0 can turn off more than one inverter at the same time, when correctly connected via the EXT IO number 3....
i could connect two of the 2P8S 24 volt batteries together or two of the 4P8S 24 volt batteries together, with each one being balanced by their own SBMS0.
With some precautions, yes. As they are using the TLP172GM for output isolation, you can literally put the appropriate control output on both SBMS0 units in series (due to the 350v rating on the TLP172GM), and use the result as a control signal indicating BOTH SBMS0 units are ON. Something like this:
<a class="ipsAttachLink ipsAttachLink_image" href="/monthly_2022_04/Untitledx.png.497eda86e120437186494c38d565b08e.png" data-fileid="1280" data-fileext="png" rel=""><img class="ipsImage ipsImage_thumbnailed" data-fileid="1280" data-ratio="57.30" width="1000" alt="Untitledx.thumb.png.01e7574a8271b79e14950c053e9e0d70.png" data-src="/monthly_2022_04/Untitledx.thumb.png.01e7574a8271b79e14950c053e9e0d70.png" src="/applications/core/interface/js/spacer.png" />
Adding insult to injury with LFP is that it's only possible to balance cells when they near 100% SOC--because otherwise, their voltage is ~3.4vpc regardless of the SOC from 20-80% (or is it 15-95%?) That coupled with a paltry 0.05A balance current--means that said BMS units' balance capability is basically useless.
I lost over thousand dollars of LFP with Daly BMS because LFP has a flat charge curve and low balance current . The LFP drop to near zero volt and can not be recharge .
I lost over thousand dollars of LFP with Daly BMS because LFP has a flat charge curve and low balance current . The LFP drop to near zero volt and can not be recharge .
You aren't the first person who's had that experience...
Two cents worth of comment on this. The piddly balance current works if you have decently matched cells and raise the cell voltages high enough to move them far enough up the curve. If you have crappy and/or mismatched cells a completely different strategy is needed, hence high current balancers and active balancers. If things are bad enough ditching top balancing completely and using bottom balancing can be a solution but that has its own bugbears.
Prebuilt elcheapo batteries often have crappy and mismatched cells. Part of their solution is to use a standard low current BMS but specify a low charge current to give the BMS a chance of keeping the cells comparatively in line. It's a dead give away that when you see a 200AH lifepo4 battery with a charge rate of 30A it's going to be crap.
5 hours ago, Sid Genetry Solar said:Regardless, seems the Daly didn't disconnect @ 2.5v on the low cell...it'd only get down to 0.2v if the cell was completely destroyed due to overcharging (resulting from inadequate balance current), or overdischarged.
It should also disconnect on cell over voltage. If the BMS is set up correctly, and actually does what it is told, all that should happen is the battery capacity falls over time as the cells get progressively further out of balance and the BMS top / tails the amp hour rating. No cell should ever be observed below 2.5V or over 3.65V. To see cells at 0.2v says something has gone badly wrong.
A technical view of the overall system involved would be interesting. Has he configured the BMS with completely incorrect settings? Has he damaged the BMS so that it can no longer do low / high voltage disconnection? Has he wired things up so that the BMS does not have the ability to disconnect the load or charger?