There is a bit more to Lithium charging than just voltage based control.

The Victron philosophy is to establish comms between battery and inverter/charger. This is mostly done via CAN bus in the Victron world but can also be done via RS485 or Serial - this comms allows a *Smart BMS* to act as system controller able to send control messages to the system's inverters/chargers who then become passive slaves.

When the inverter/charger can talk to the battery, you are able to access more energy and charge better and faster. In the Victron world, three control parameters dynamically obtained from a smart BMS are used to manage battery charging.

Charge Current Limit - CCL - for Pylontech, allows battery to request a max 0.5c and a min 0.2c charge rate at different SoCs

Discharge Current Limit - DCL - makes it so that you are forced to throttle loads as the SoC drops below 10% - you can no longer do 0.5c discharge rates past 10% SoC

Charge Voltage Limit - CVL - Dynamically adjusts to achieve 100% charge and also take care of cell imbalances so that no cell is overcharged even though there is massive imbalance in the cells - I have seen BMS elegantly limit CVL to 50v in a scenario where 2 cells out of 15 had issues - this was sustained for about a week until the balancers were able to bring the entire pack back into balance.

In a moderate to large system running off Lithium batteries, you really want to have a truly Smart BMS capable of comms - fixed voltage charging in a Lithium profile may not cut it and it is entirely possible to overcharge some cells or destroy your batteries even though overall system wide voltage limits are within spec.

In my case with Victron talking to Pylontech, the Pylontech BMS broadcasts a control parameter called charge current limit - CCL of 800amps when battery is low, this allows the inverter and MPPTs to run full throttle pushing in a combined 22kw (my installed hardware limit) of charge current until about 90% SoC when they throttle charging so the cells don't swell or heatup.

Further, because the batteries can report SoC, I am able to set precise Gen Start/Stop parameters and a host of others to achieve an optimal system.

This is why one would pay a premium for truly Lithium compatible equipment beyond just setting a Lithium charge voltage profile.

adrusa:


I don't know what else "lithium profile" on a charger mean other than setting bulk, absorption and float voltage to the same value and disable equalization. That is exactly what happens when I select "lithium profile" from victron charger. As to the fear of continuous float charges on the battery, the BMS usually does the remaining. When my lithium batteries enter "float" the current meters read zero.

So, if you have a perfectly good charger (inverter or Charge controller) on which you can modify the charging parameters, I don't see the need to waste extra money on any "lithium" profile, I honestly think it is a scam for manufacturers to make a little extra money on selling their inverters and chargers.

How may I contact you ?

Valto:
yes it's available. 18000. it is a dc/ac 18inches with usb and remote (25w consumption on highest speed. can work with 12v batteries, 12v to 18V solar panels and direct to 220v utility.

dejidotun2000:
How may I contact you ?

call or whatsapp 0802-057-4628

The key word is *dynamically* adjustable charging profile that can respond to *cell* level events (voltage, SoC, temperature).

In a multi cell Lithium battery pack, this necessarily requires communication between BMS and Inverter - this is the reason why the elite manufacturers only released Lithium support in their equipment with comms and the Axperts and smaller players rushed to add additional cards e.t.c to their inverters to achieve 'Lithium compatibility' which is essentially communications between inverter/charger and battery.

Indeed their is more to stable, long term use of a large Lithium battery pack than just setting charge voltages and LVD.

Oshomo12:


You are very correct, just get something that has an adjustable charging profile, that's all!

I have been nearly 100% offgrid over 6 years and running ACs off my system for ~4 of those years.

The system performance when using lead acid was average, I would get a little over 2 years from my battery as the battery was deep cycled daily with 2 ACs running almost 24/7.

Now that I have ported to Lithium the experience is far better - 18months 100% OFFGRID running 2 units 1hp ACs 24/7 and another 5 ACs opportunistically off a 48Kwh Pylontech bank and the batteries have performed outstandingly - no discernible degradation, no capacity loss and cell level state of health in excellent shape.

You really have to size the system appropriately viz number and wattage of panels, battery size and BATTERY TYPE - certainly Lithium batteries do far better in high discharge rate applications - with proper design, I was able to dump all my inverter ACs in favor of standard ACs so I could enjoy better cooling performance - so a trade up in all aspects for me - everyone's situation and mileage may vary though.

With all the ruckus about Deye inverters, I could not help but pickup a new 8kw unit as well as a couple of new Lishen 280Ah cells to try things out - once I have the system integrated into my existing one, I will be in a position to run at least 4 1hp ACs 24/7.

By now, I have run out of spare internal organs to sell to afford Lithium so I had to sell off some Pylontech bricks to finance the Deye inverter and Lishen cells.

I find that most folks do not really run their ACs 24/7 or overnight - on average you would need about 1kwh of battery storage per 1hp standard AC and about 600wh of battery storage per 1hp inverter AC if running overnight (you get better mileage if you allow the inverter units run continuously). Day time use you need at least 2kw PV to run 1hp AC and size up to 4kw or more if you need to replenish battery capacity that was spent overnight to power thesame AC.

The ugly truth about offgrid living with high energy consumers e.g. ACs is that you will likely need a generator from time to time - the premium inverters like Victron incorporate a power assist feature so that you can use the smallest possible generator size e.g a 5kva generator to drive a 15kva inverter AND automatic Gen start/stop based on SoC, battery voltage and AC loads so that the Gen can run the minimum possible amount of time - you can even set exercise hours so that the Gen battery and internals stay ready for use any time.

mctfopt:
Genuinely out of curiosity, is anyone running ACs or AC off their renewable system? If yes, what is the minimum battery and PV they running it off and how has the performance being?

NiyiOmoIyunade:
This is an interesting design question - one that begins to come up more as we get larger and larger panel sizes e.g 385w, 435w, 535w due to tech advancements yet the traditional CC manufacturers are sticking to the standard 150v ceiling or you already have 150v CC on hand and unwilling to upgrade.

From the point of view of the charge controller, the VoC is a momentary value just before the internal circuitry engages and begins to take/make power from the panels.

A 3s config with ~49v VoC panels will work with a 150v capped CC in the following scenarios.

1) You are located in the tropics with ambients generally over 30°C - there is an inverse relationship between temperature and VoC so your observed VoC will be less than the panel spec at 25°C STC

2) The panels will mostly be at open circuit in the early mornings and late evenings - both of these times are associated with poor illumination so the reference VoC will never be attained. In the case of an afternoon disconnect creating open circuit condition, the ambient temperature in the tropics is high enough that the actual VoC is less than spec

In summary the fact that your ambient temperature is higher than reference and your illumination is lower than reference allows you to get away with a nearly 150v VoC on a 150v capped CC.

Should the day come when you have an 10°C ambient and perfectly clear skies and full sun - you may well brick the CC permanently.

If you installed in Jos for example or some parts of the North that get really cold yet have full sun and clear skies, you would have to do extra work so that the install stands the test of time.

Hybrid inverter manufacturers are keeping up with the pace of change.

NiyiOmoIyunade:
I have been nearly 100% offgrid over 6 years and running ACs off my system for ~4 of those years.

The system performance when using lead acid was average, I would get a little over 2 years from my battery as the battery was deep cycled daily with 2 ACs running almost 24/7.

Now that I have ported to Lithium the experience is far better - 18months 100% OFFGRID running 2 units 1hp ACs 24/7 and another 5 ACs opportunistically off a 48Kwh Pylontech bank and the batteries have performed outstandingly - no discernible degradation, no capacity loss and cell level state of health in excellent shape.

You really have to size the system appropriately viz number and wattage of panels, battery size and BATTERY TYPE - certainly Lithium batteries do far better in high discharge rate applications - with proper design, I was able to dump all my inverter ACs in favor of standard ACs so I could enjoy better cooling performance - so a trade up in all aspects for me - everyone's situation and mileage may vary though.

With all the ruckus about Deye inverters, I could not help but pickup a new 8kw unit as well as a couple of new Lishen 280Ah cells to try things out - once I have the system integrated into my existing one, I will be in a position to run at least 4 1hp ACs 24/7.

By now, I have run out of spare internal organs to sell to afford Lithium so I had to sell off some Pylontech bricks to finance the Deye inverter and Lishen cells.

I find that most folks do not really run their ACs 24/7 or overnight - on average you would need about 1kwh of battery storage per 1hp standard AC and about 600wh of battery storage per 1hp inverter AC if running overnight (you get better mileage if you allow the inverter units run continuously). Day time use you need at least 2kw PV to run 1hp AC and size up to 4kw or more if you need to replenish battery capacity that was spent overnight to power thesame AC.

The ugly truth about offgrid living with high energy consumers e.g. ACs is that you will likely need a generator from time to time - the premium inverters like Victron incorporate a power assist feature so that you can use the smallest possible generator size e.g a 5kva generator to drive a 15kva inverter AND automatic Gen start/stop based on SoC, battery voltage and AC loads so that the Gen can run the minimum possible amount of time - you can even set exercise hours so that the Gen battery and internals stay ready for use any time.

Thank you for this super detailed response. I may just get me some Deye inverter as they have been in my cart for so long.

When you ran off lead acid battery, which size of battery did you use that needed change after two years and what was the size of the PV system?

I understand the need to run off regular AC as I've noticed that you trade performance for low energy when you go the inverter AC route.

Lishen, CATL, EVE all happen to be in the same WhatsApp group for most DIYers across the world.

I have another question for the house, is anyone here into EV or at least the younger bro electric bicycles/scooter etc? I hope I'm not alone here. Lol.

Oshomo12:


I need clarification here, 10kva (8kw), or 8kva, which one are you using? cos I am seeing 8kw

8kw I no type 10kva o....8kw Deye inverter

Is there anything i can do to save a runaway battery?.
Voltage gets to 15.6volts, while other batteries in series are 14.4volts.
From the graph we can see the history, will upload another image when its really high.

I have added a balancer last week, but nuthing appears to be changing

Battery C is the bad battery with the voltage spikes, green graph too.
4fla in series

At that time I had 48v 800Ah of Gel batteries, PV array was 7.56Kw.

I have been looking at an electric bike called a 'Rungu Kilimanjaro' - something for recreation and exercise but with enhanced stability (2 front wheels) - I am a bit of an extreme sports fan - ride quads and jet skis a lot.

mctfopt:


Thank you for this super detailed response. I may just get me some Deye inverter as they have been in my cart for so long.

When you ran off lead acid battery, which size of battery did you use that needed change after two years and what was the size of the PV system?

I understand the need to run off regular AC as I've noticed that you trade performance for low energy when you go the inverter AC route.

Lishen, CATL, EVE all happen to be in the same WhatsApp group for most DIYers across the world.

I have another question for the house, is anyone here into EV or at least the younger bro electric bicycles/scooter etc? I hope I'm not alone here. Lol.

mctfopt:


Lishen, CATL, EVE all happen to be in the same WhatsApp group for most DIYers across the world.

I have another question for the house, is anyone here into EV or at least the younger bro electric bicycles/scooter etc? I hope I'm not alone here. Lol.

which Washpap group? kindly share.

Very interested in EVs. These will be the next accomplishment of the solar cadres. All that excess afternoon solar going into your transport!!
Then go bigger, and set up a charging station for your neighbours.

Africa will shock the world with adoption of affordable EV especially bicycles (mountain bike style for all terrain), keke trikes (for commercial taxis), and scooters (for neighborhood runs if you have smooth roads). Let me know if you want to make a business of these.
You are not alone. You are ahead.

Me, I no get money for isho, i dey plan ile-ala ja gogoro!! And not gogoro the Asian battery swap e-bike mobility business, either.

Valto:
guess it is 32pcs eve 280ah cells.. the 310ah should be CATL...

How far with the next LiFePO4 group buy?
My kidney is ready for harvesting.

remizvxcq:


How far with the next LiFePO4 group buy?
My kidney is ready for harvesting.

there is no group buy at the moment.its now individual stiuff. however u can easily buy and ship by yourself.u can contact me for heads up..

Why sell pylontech to buy Listen, couldn't you have used the pylontech with the Deye inverter ?

How do you hope to connect the two Lishen cells to a 48V Deye inverter ?

NiyiOmoIyunade:



With all the ruckus about Deye inverters, I could not help but pickup a new 8kw unit as well as a couple of new Lishen 280Ah cells to try things out - once I have the system integrated into my existing one, I will be in a position to run at least 4 1hp ACs 24/7.

By now, I have run out of spare internal organs to sell to afford Lithium so I had to sell off some Pylontech bricks to finance the Deye inverter and Lishen cells.

ojeysky:


8kw I no type 10kva o....8kw Deye inverter

You did not get my question,
Deye has 10kva(rated also 8kw), 6.5kva(also rated 5kw) etc.

Which deye model are you using, SUN-7.6K?

NiyiOmoIyunade:
There is a bit more to Lithium charging than just voltage based control.

The Victron philosophy is to establish comms between battery and inverter/charger. This is mostly done via CAN bus in the Victron world but can also be done via RS485 or Serial - this comms allows a *Smart BMS* to act as system controller able to send control messages to the system's inverters/chargers who then become passive slaves.

When the inverter/charger can talk to the battery, you are able to access more energy and charge better and faster. In the Victron world, three control parameters dynamically obtained from a smart BMS are used to manage battery charging.

Charge Current Limit - CCL - for Pylontech, allows battery to request a max 0.5c and a min 0.2c charge rate at different SoCs

Discharge Current Limit - DCL - makes it so that you are forced to throttle loads as the SoC drops below 10% - you can no longer do 0.5c discharge rates past 10% SoC

Charge Voltage Limit - CVL - Dynamically adjusts to achieve 100% charge and also take care of cell imbalances so that no cell is overcharged even though there is massive imbalance in the cells - I have seen BMS elegantly limit CVL to 50v in a scenario where 2 cells out of 15 had issues - this was sustained for about a week until the balancers were able to bring the entire pack back into balance.

In a moderate to large system running off Lithium batteries, you really want to have a truly Smart BMS capable of comms - fixed voltage charging in a Lithium profile may not cut it and it is entirely possible to overcharge some cells or destroy your batteries even though overall system wide voltage limits are within spec.

In my case with Victron talking to Pylontech, the Pylontech BMS broadcasts a control parameter called charge current limit - CCL of 800amps when battery is low, this allows the inverter and MPPTs to run full throttle pushing in a combined 22kw (my installed hardware limit) of charge current until about 90% SoC when they throttle charging so the cells don't swell or heatup.

Further, because the batteries can report SoC, I am able to set precise Gen Start/Stop parameters and a host of others to achieve an optimal system.

This is why one would pay a premium for truly Lithium compatible equipment beyond just setting a Lithium charge voltage profile.

I honestly don't believe a word of these very technical and deliberately confusing points. And I'm not talking about what you wrote, but what the battery, BMS and charger manufacturers have clearly made you to believe. I continue to believe that most of these talks are basically to make you pay more for pre-existing technology given a new name. One thing I'm prepared to concede is that battery manufacturers may set stringent conditions for their batteries as a way of ensuring that warranty claims are not too burdensome. If a car can do 100Km/h, the manufacturers will be happy to limit you to 50Km/h knowing that the chances of damage is much lower at that speed. So, they may tell you not to charge at 1C or 0.5C or whatever tickles their fancies. With a good BMS, you can actually be a bit liberal with your lithium batteries. Your BMS should stand between your battery and any problem. The chances are that you will be seriously under-utilizing your batteries if you strictly follow manufacturers guidelines. Lithium can actually take as high as 1C charging current. That is why phone manufacturers are doing all sorts of high current charging, warp charging, flash charging, superspeed charging etc.

I also understand why installers may want to push premium and extra-protected system to clients. It reduces support calls and increases your business reputations. But, as a DIY guy, I have better ways to spend my money than buying bogus technologies that add little or nothing to my setup. I have used Victron "Lithium Profile" before and I see no advantage over my current setup with Outback and Felicity CCs and Inverters.

No I sold 4 units out of my 20 Pylontechs and replaced with 32pcs 3.2v 280Ah Lishens.

The remaining 16 Pylon US2000s will continue to run off my 15kva Victron inverter while the Deye 8kw will be paired with the 48v 560Ah of Lishens.

I have contrived an arrangement where the 15kva Victron will transfer loads over to the 8kw Deye once the Pylontechs are at 40% SoC - this is essentially replacing my Generator autostart if I run loads aggressively (4 ACs late into the evening)

In the past heavy loads taking the battery to 35% SoC would trigger a Gen start for 1 hour, now instead of a Gen start it will trigger a load transfer to the Deye which will then run to 20% SoC before starting the Generator.

From 48kwh of Pylontech and 38kwh useable energy, I now have a combined 67kwh battery bank of which I can use 60kwh.

See attached pics when I took delivery of the cells and trying to figure out how best to arrange them.

dejidotun2000:
Why sell pylontech to buy Listen, couldn't you have used the pylontech with the Deye inverter ?

How do you hope to connect the two Lishen cells to a 48V Deye inverter ?

NiyiOmoIyunade:
No I sold 4 units out of my 20 Pylontechs and replaced with 32pcs 3.2v 280Ah Lishens.

The remaining 16 Pylon US2000s will continue to run off my 15kva Victron inverter while the Deye 8kw will be paired with the 48v 560Ah of Lishens.

I have contrived an arrangement where the 15kva Victron will transfer loads over to the 8kw Deye once the Pylontechs are at 40% SoC - this is essentially replacing my Generator autostart if I run loads aggressively (4 ACs late into the evening)

In the past heavy loads taking the battery to 35% SoC would trigger a Gen start for 1 hour, now instead of a Gen start it will trigger a load transfer to the Deye which will then run to 20% SoC before starting the Generator.

From 48kwh of Pylontech and 38kwh useable energy, I now have a combined 67kwh battery bank of which I can use 60kwh.

See attached pics when I took delivery of the cells and trying to figure out how best to arrange them.

Wow! 60KWh of useable battery power is a lot. It is about 3 times what I use daily.

mctfopt:
Genuinely out of curiosity, is anyone running ACs or AC off their renewable system? If yes, what is the minimum battery and PV they running it off and how has the performance being?

I run a single 1.5Hp LG AC on my system. The AC is located in my bedroom and it works in bursts of 1, 2 or 3 hours, maximum of 6 hours per night. I tend to do more of 4 hours than 6 hours. I have a total lithium power of about 600AH and I'm not shy of pushing it down to as low as 30%.

Chai! Baba, cut Lithium for me na!

mctfopt:


This is awesome to hear. The 5.2kw PV is it premium make or just Chinese type? I do see Deye online, didn't know they make really cool inverters. My neighbour just had these bad boys delivered.

Lmao. It probably can happen in the south during less dust severe harmattan. Clear skies, chilly day, full midday sun......magic smoke released!

NiyiOmoIyunade:
This is an interesting design question - one that begins to come up more as we get larger and larger panel sizes e.g 385w, 435w, 535w due to tech advancements yet the traditional CC manufacturers are sticking to the standard 150v ceiling or you already have 150v CC on hand and unwilling to upgrade.

From the point of view of the charge controller, the VoC is a momentary value just before the internal circuitry engages and begins to take/make power from the panels.

A 3s config with ~49v VoC panels will work with a 150v capped CC in the following scenarios.

1) You are located in the tropics with ambients generally over 30°C - there is an inverse relationship between temperature and VoC so your observed VoC will be less than the panel spec at 25°C STC

2) The panels will mostly be at open circuit in the early mornings and late evenings - both of these times are associated with poor illumination so the reference VoC will never be attained. In the case of an afternoon disconnect creating open circuit condition, the ambient temperature in the tropics is high enough that the actual VoC is less than spec

In summary the fact that your ambient temperature is higher than reference and your illumination is lower than reference allows you to get away with a nearly 150v VoC on a 150v capped CC.

Should the day come when you have an 10°C ambient and perfectly clear skies and full sun - you may well brick the CC permanently.

If you installed in Jos for example or some parts of the North that get really cold yet have full sun and clear skies, you would have to do extra work so that the install stands the test of time.

adrusa:


I run a single 1.5Hp LG AC on my system. The AC is located in my bedroom and it works in bursts of 1, 2 or 3 hours, maximum of 6 hours per night. I tend to do more of 4 hours than 6 hours. I have a total lithium power of about 600AH and I'm not shy of pushing it down to as low as 30%.

You're using a 24V or 48V system?

Oshomo12:


You did not get my question,
Deye has 10kva(rated also 8kw), 6.5kva(also rated 5kw) etc.

Which deye model are you using, SUN-7.6K?

I have SUN-8K do you have a reference where it's stated that it's 10kva? Because I think that is actually the max PV string input.

Indeed you are correct that one does not always need all these additional overhead and gimmickery but in medium to large systems and especially commercial installations, one cannot do without these addons if you want a truly robust installation. I also agree with you most heartily that the manufacturers have set the BMSs to be really conservative, making it harder to abuse the battery and easier to make or exceed the promised life.

If I could put it simply, you are able to utilise the battery better and safer if you go beyond just a BMS installed to having active communication between the inverter and battery BMS.

I say this because I have access to cell level monitoring data for quite a large number of installations and I can see differences for systems where the BMS actively controls the charge profile vs those where we have implemented just voltage based control.

Some cases where it is a very good idea to be able to have the BMS actively talk to the inverter.

1) 'Low Voltage Disconnect' based on BMS reported state of charge % - Is better implemented when the inverter can read SoC information directly from the battery. Especially in situations of partial charge and/or running large loads, voltage becomes fairly inaccurate to help you know when to stop using your battery - I quickly saw that when the Pylons reported 20% SoC, voltage was still well above 3.2v per cell, we were able to play with lowering the SoC cutoff until we found a sweet spot closer to 3.2v or very slightly below - this meant 2 to 5 more hours backup time for some customers.

With purely voltage based control, your inverter may cross the LVD while running large loads because the voltage sags (despite Lithium's fairly flat voltage curve) yet you still have enough juice left in the battery or even have the BMS cutoff power while the voltage is above LVD threshold because of successive days of partial charge (Oga Chris has a video where he experienced the BMS cutting off due to low state of charge while battery voltage appeared in the still useable range)

2) If your system has an automatic Gen start/stop built in, you can have finer control of when to call for the Gen to assist the batteries and minimse Gen run time and costs when the BMS can communicate battery status directly to the rest of the system, things like diversion loads, capture excess PV production and a host of other features work better when inverter and battery can communicate.

I can tell you for free that these features properly deployed have helped customers capture huge savings in diesel and generator maintenance costs (Gens run far less) when the Gen can respond based on actual battery state of charge vs just voltage.

3) Cell Status Within a Battery Pack - it is entirely possible to set your desired charge profile on the inverter and yet still overcharge some cells that are out of sync with the rest of the battery pack. Where you have comms between BMS and inverter, what you have set is the not to exceed charge voltage, the BMS can actively instruct the inverter to lower this overall charge voltage to elegantly deal with a divergent cell - any other scenario without comms, the BMS disconnects you and you have to figure things out yourself.

4) In an integrated system with comms between inverter and BMS, you get nice polite emails and notifications of system status e.g load threshold breached, internet service down, battery running low and time to go, generator is ON/OFF, grid is restored/lost with not much extra work beyond logging into a monitoring portal.

The plethora of information relating to both battery and general system status can be very useful and customers are indeed happy to pay good money to have this information on tap and constant reassurances that their system is working well. Again if your only goal is for the battery to power loads, all these extras are not of much use or relevance.

adrusa:


I honestly don't believe a word of these very technical and deliberately confusing points. And I'm not talking about what you wrote, but what the battery, BMS and charger manufacturers have clearly made you to believe. I continue to believe that most of these talks are basically to make you pay more for pre-existing technology given a new name. One thing I'm prepared to concede is that battery manufacturers may set stringent conditions for their batteries as a way of ensuring that warranty claims are not too burdensome. If a car can do 100Km/h, the manufacturers will be happy to limit you to 50Km/h knowing that the chances of damage is much lower at that speed. So, they may tell you not to charge at 1C or 0.5C or whatever tickles their fancies. With a good BMS, you can actually be a bit liberal with your lithium batteries. Your BMS should stand between your battery and any problem. The chances are that you will be seriously under-utilizing your batteries if you strictly follow manufacturers guidelines. Lithium can actually take as high as 1C charging current. That is why phone manufacturers are doing all sorts of high current charging, warp charging, flash charging, superspeed charging etc.

I also understand why installers may want to push premium and extra-protected system to clients. It reduces support calls and increases your business reputations. But, as a DIY guy, I have better ways to spend my money than buying bogus technologies that add little or nothing to my setup. I have used Victron "Lithium Profile" before and I see no advantage over my current setup with Outback and Felicity CCs and Inverters.

Is this not just a conversion problem for the OP?

10Kva is about 8Kw where the power factor is assumed to be 0.8

ojeysky:


I have SUN-8K do you have a reference where it's stated that it's 10kva? Because I think that is actually the max PV string input.

adrusa:


I honestly don't believe a word of these very technical and deliberately confusing points. And I'm not talking about what you wrote, but what the battery, BMS and charger manufacturers have clearly made you to believe. I continue to believe that most of these talks are basically to make you pay more for pre-existing technology given a new name. One thing I'm prepared to concede is that battery manufacturers may set stringent conditions for their batteries as a way of ensuring that warranty claims are not too burdensome. If a car can do 100Km/h, the manufacturers will be happy to limit you to 50Km/h knowing that the chances of damage is much lower at that speed. So, they may tell you not to charge at 1C or 0.5C or whatever tickles their fancies. With a good BMS, you can actually be a bit liberal with your lithium batteries. Your BMS should stand between your battery and any problem. The chances are that you will be seriously under-utilizing your batteries if you strictly follow manufacturers guidelines. Lithium can actually take as high as 1C charging current. That is why phone manufacturers are doing all sorts of high current charging, warp charging, flash charging, superspeed charging etc.

I also understand why installers may want to push premium and extra-protected system to clients. It reduces support calls and increases your business reputations. But, as a DIY guy, I have better ways to spend my money than buying bogus technologies that add little or nothing to my setup. I have used Victron "Lithium Profile" before and I see no advantage over my current setup with Outback and Felicity CCs and Inverters.

There was a time we used to talk about DIY LFP Vs premiums and there was a time I would have responded to Oga neyo that the idea he has isn't accurate. There are a few scenarios where littium cells may not charge optimally but none of them has anything to do with the inverter talking to the BMS or not.

Having the inverter talk to the BMS is a good to have as you get to see the individual cell voltages, and maybe set triggers based on individual cell status apart from that, it's a charge and stop that remains. Even when I was using Felicity and MPP which both has float bugs, I could still charge my lithium optimally by working around the voltage to avoid the float bug.

NiyiOmoIyunade:
Is this not just a conversion problem for the OP?

10Kva is about 8Kw where the power factor is assumed to be 0.8

Ah yes, that could probably be the case.

NiyiOmoIyunade:
No I sold 4 units out of my 20 Pylontechs and replaced with 32pcs 3.2v 280Ah Lishens.

The remaining 16 Pylon US2000s will continue to run off my 15kva Victron inverter while the Deye 8kw will be paired with the 48v 560Ah of Lishens.

I have contrived an arrangement where the 15kva Victron will transfer loads over to the 8kw Deye once the Pylontechs are at 40% SoC - this is essentially replacing my Generator autostart if I run loads aggressively (4 ACs late into the evening)

In the past heavy loads taking the battery to 35% SoC would trigger a Gen start for 1 hour, now instead of a Gen start it will trigger a load transfer to the Deye which will then run to 20% SoC before starting the Generator.

From 48kwh of Pylontech and 38kwh useable energy, I now have a combined 67kwh battery bank of which I can use 60kwh.

See attached pics when I took delivery of the cells and trying to figure out how best to arrange them.

That set-up will almost guarantee that your Gen will mostly not get triggered again. So it means you will be using the Gen port on Deye or what do you intend to use for the trigger?

microgiant:


I already ordered at ₦ 42,848.00 including delivery, which is cheaper for me.

How were you able to sideline the 100usd monthly limit on ATM card online transactions by some of those banks while others peg theirs at around 50 usd?

Or has the limit now been raised above 100usd?

But omo, naira don kpafuka o. PowMr used to be 28k, then it moved to 32k. Now it's 42k, and I'm sure that one na with AliExpress standard shipping, not expedited ones like UPS or FedEx which will require around another 25k for delivery charges.

NiyiOmoIyunade:
At that time I had 48v 800Ah of Gel batteries, PV array was 7.56Kw.

I have been looking at an electric bike called a 'Rungu Kilimanjaro' - something for recreation and exercise but with enhanced stability (2 front wheels) - I am a bit of an extreme sports fan - ride quads and jet skis a lot.

Rungu is rugged, I'm thinking of getting a RadRunner

The gel battery you've got then was pretty huge. That's why I often don't advise people to run their ACS off their smaller systems.

litaninja:
Chai! Baba, cut Lithium for me na!

You can do even more. If you want to. Chinese making it easier by the day.

olopan:
Personally in our design, we mostly consider MPPT range, since most low PV input charge controllers do not consider start-up voltage as most high PV input of hybrid inverter and grid-tie inverters, anything that sits within the MPPT range is fine.

We have had felicity charge controllers a clone of MPP controllers show error of high voltage on very sunny days because a 3s is used but will never or hardly happen when 2S is used on them

Since each installation comes with a unique solution, their is no rule of thumb that apply to all.

With those high VoC panels, 2s can be applicable comfortably then so far the SCC can not tolerate 3s. I think I don't mind those panels though, but the problem go be the installation. They're gonna be fairly heavy to lift.

Another thing I wonder is if lower VoC panels have been pre-installed in the 3s configuration and one requires adding more panels for upgrade, will it be appropriate to now include these high VoC ones in 2s configuration into the mix, in parallel configuration of course?