I liked this one! I couldn't find anything serious to critique this time. I'd just add, on spec'ing cable amperages, even if the insulation can handle high temps you still don't want high temps in your system for a variety of reasons. Most prominently, voltage drop and thermal cycling causing connections to loosen over time. Under-sizing cables is mainly a legacy 12V issue where people with 12V systems just couldn't afford super-huge 4/0 cabling to handle the currents they wanted to work with. It is entirely unnecessary on a 24V or 48V system. So always use 60C or "AWG for power transmission" tables in higher-voltage systems. -Matt
Undersizing cables can also happen in 24 or 48V systems. I don't recommend using only 60°C insulation rating because the wires will have to be bigger to support the same current as a 105°C wire would.
@@cleversolarpower Do you really want 105C (221F) cables anywhere in your system? Connecting batteries, equipment, or running through a wall, or between compartments in an RV? Or pre-heating fuses and breakers in the cabling path? Starting to see the problem? Running cables hot is a 12V thing. It is entirely unnecessary at higher voltages... for example, at 48V, 2 AWG translates to 5000W and the cables only get a bit warm to the touch. When you have the choice, keep things cool. You can still use cables rated for 105C... that's a good idea, but you don't have to size the cables to actually run even remotely that hot. -Matt
@@junkerzn7312 Using 105°C cables does not mean they will get hot. They are rated for higher current. If you size your wires correctly, they will not get warm.
Thanks big boss for your devoted and educative lecture . Best regards . To carry out load analysis on a system with Switch mode power supply ( SMPS), Can one use the Amp and Voltage rating on the SMPS for load analysis. e.g adapter for laptop charging
I just get the biggest of everything I can. I have a 12kw transformer inverter in fitting soon and currently 20kw of 48v battery. The inverter in using now is only 5.6kw. not enough. I will need to up size the battery to at least 50kw to make it worthwhile. I also have one victron rs450/100tr charge controller to start with. I'll be going with 120mm2 cable and 300a nt2 blade fuse. During any blackouts I can sell energy to the neighbours. At a free market rate of course😂
in regards to charge and discharge rates. is the charge rate a per hour measurement? 0.2c seems to me like it would drain a lead acid tubular battery to 50% in 5 hours. am i getting this correct or no? what if you need it to last you 24 hours? or 72?
C-rate is a current measurement based on the batteries capacity. 1C @100ah=100A. To answer your question: 12V * 100Ah = 1200Wh of stored energy, but you can only use 50%, so thats 600Wh. 0.2C of 100Ah is 20A at 12V= 240Wh. 600Wh/240Wh=2.5h running time.
I have a question who inverter companies don't give a good answer, they said you can charge your battery bank with external generator connecting to your inverter charger, what kind of wave they don't say , pure shine or square or modify,I think only pure shine ,but most generators in the market still use square or modify.
There is a difference between inverter/generators and normal generators. The first have better sine waves, the latter have more 'dirty' power which not all inverters can take. I'm not aware of any inverters create a modified sine wave.
Good day sir, I have 2 250W solar panels and one tall tubular 12v 240ah battery and a 30A charge controller, I am using an egg incubator which runs 24/7 on AC 1000W inverter charger, my charge controller shows my usage 7A on average, sometimes it's not sufficient for my incubator and it turns off, so what could be the problem, please help on this regard.
7A*12V=84W*24h=2000Wh. you only bring in 1500Wh with 3 sunhours per day. Your battery is 2880Wh. You need to increase battery power and put more solar panels.
@@cleversolarpowerif I add one 12v 100ah battery, and connect a 250 solar panel to it without a charge controller for day time usage, will it be enough for day use? And can a 250w solar panel charge my 12v 240ah battery alone for night use? Will this setup work?
Hi @Cleversolarpower, this is Grandpa Emil, one of your avid subscribers in the Philippines. Will it be possible to make a YT video about the proper way of charging and discharging powerstations? I am currently using a Pecron E1500LFP and since I pretty much would like to make the batteries last longer, I would want to know the proper way of charging/discharging/storing it. There are several schools of thought on this matter which, instead of helping me, sadly, it made my brain explode: (1) Some experts suggest to maintain at least 20% of its battery capacity before charging/topping it again for the next use. In relation to this, will it affect the one (1) cycle count if, say, I re-charge it back to 100% from 20% remaining viz zero percent because from what I've read, generally, a cycle is depleting the battery from 100% to 0%. (2) On the other hand, some would advice to charge/top it to just around to 80% (not 100%) before its next use. (3) Still, other experts would suggest that when storing LFP powerstaions, charge it between 40% to 50%. Then use it after 3 months of storage to maintain its battery life (roughly 3500+ battery cycles). That said, based on your experience and hopefully thru actual tests concerning the same, can you please provide us in one of your future videos the proper way of charging/discharging/storing powerstations with LFP batteries or any other battery chemistry, for that matter? Thank you.
I recommend cycling a lithium battery from 10% to 90%. Normally you would program this in your charge controller and BMS of the battery. However, i don't think thats possible with power stations. Let's say your power stations battery can last 3500 cycles. That's still 10 years of use when you do one cycle every day. I think the electronics will die sooner than the battery itself. And after 3500 cycles you still have 80% capacity left. So don't worry about optimizing cycle life. Storage is around 30 to 50% charge, but again, that doesn't really matter.
12V only makes sense for use in an RTV. 24V has a big advantage: Sensors, plc etc. run on 24V. You will do hard finding components in industry quality for 12 or 48V, when building some sort of control system with a big battery backup. 48V is good for diy battery storage systems.
Why is it that everyone that does such explanations with using a 3000w inverter on 12v and suggesting cable size and fuses etc with the equation of 3000/12 fails to take into account that battery voltage when low or reaching BMS or inverter cut off may fall to 10v or even 9v. Cable, fuse, and even your 1.25 safety factor margin are out the window without taking the lower voltages into account. It's simple to say don't build such high powered 12v systems but there's situations such as in smaller recreational vehicles where 24v or 48v does not make sense.
He invested his time to make a video that is useful for certain people. He should be applauded. Nobody can satisfy everyone. If you have observed a gap in the knowledge, make a video about it and fill in the gap. That is why knowledge and learning are never ending.
@@1982757 I do applaud his knowledge and efforts. I asked a question and didn't receive an answer. I don't need to make a video or to have someone simping for him because you see my comment as a criticism. It has nothing to do with pleasing everyone. If voltage drops, amp draw increases. If you can't answer the question either then your comment is hardly useful.
Lithium batteries are 12V at 10% and 10V at 0%. If we use 10V as the worst case, then you will have 3000W/10V=300A. If we use 12V as the lowest reference, which was used in this video, we get: 3000W/12V=250A, multiplied by the safety factor of 1.25, we get 313A. This is still more than the 300A in the worst case scenario, so this passes. Your wire size and fuse size will both be larger than this. We will use a 2/0 cable which can carry 325A with a 300A fuse. Now you might think that a 300A fuse is too low. If we look at the datasheet, we can see that the fuse will never trip at 300A. Only at 525A after 16 minutes. Hope this answers your question.
@@cleversolarpower Thank you for your reply. You state that Lithium batteries are 10% when at 12v and 10v at 0%. I don't profess to be an expert and I'm learning more by asking questions, but surely that would only be true at a unloaded resting SOC voltage? Though lithium batteries are not as susceptible to extreme voltage sag under large continuous load as lead acid batteries are they still do suffer from it. Thus a 3000w inverter could run for some time at 10v 'if' the BMS or inverter cut off voltage is set that low. So, the battery voltage may be 10v but it's not truly at zero percent charge and without load it would recover to a higher voltage and the inverter would likely switch back on again. Which is one of the reasons voltage is far less useful as a guide to SOC with lithium compared to lead acid and shunts are more accurate. Also, with regards to cable size I would like to point out that despite standards (and here in Aus we use the B&S standard) not all cables sold from different manufacturers as a given size are created equal with regards to amp rating. Using generic data sheets rather than specific manufacturers data sheets for the brand of cable is asking for trouble. Then there's the reduction in current carrying capacity as ambient temp increases. Most cable ratings best figures are at say 25c. In a recreational vehicle traveling around in full summer inside temps can be double that.
📖 My Best-Selling book on Amazon: cleversolarpower.com/off-grid-solar-power-simplified
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I liked this one! I couldn't find anything serious to critique this time. I'd just add, on spec'ing cable amperages, even if the insulation can handle high temps you still don't want high temps in your system for a variety of reasons. Most prominently, voltage drop and thermal cycling causing connections to loosen over time.
Under-sizing cables is mainly a legacy 12V issue where people with 12V systems just couldn't afford super-huge 4/0 cabling to handle the currents they wanted to work with. It is entirely unnecessary on a 24V or 48V system. So always use 60C or "AWG for power transmission" tables in higher-voltage systems.
-Matt
Undersizing cables can also happen in 24 or 48V systems. I don't recommend using only 60°C insulation rating because the wires will have to be bigger to support the same current as a 105°C wire would.
@@cleversolarpower Do you really want 105C (221F) cables anywhere in your system? Connecting batteries, equipment, or running through a wall, or between compartments in an RV? Or pre-heating fuses and breakers in the cabling path? Starting to see the problem?
Running cables hot is a 12V thing. It is entirely unnecessary at higher voltages... for example, at 48V, 2 AWG translates to 5000W and the cables only get a bit warm to the touch.
When you have the choice, keep things cool. You can still use cables rated for 105C... that's a good idea, but you don't have to size the cables to actually run even remotely that hot.
-Matt
@@junkerzn7312 Using 105°C cables does not mean they will get hot. They are rated for higher current. If you size your wires correctly, they will not get warm.
Thank you very much
Interesting man. Leaner from India.
Hello and thanks for letting us learn with you . I bought your book. And I'm been reading it and leaving a lot .
Educative, i have learnt alot from you battery discharge explanation. It will sure help when i choose batteries for a setup.
Thank you sir.
Glad it was helpful!
Thanks big boss for your devoted and educative lecture . Best regards . To carry out load analysis on a system with Switch mode power supply ( SMPS), Can one use the Amp and Voltage rating on the SMPS for load analysis. e.g adapter for laptop charging
I just get the biggest of everything I can. I have a 12kw transformer inverter in fitting soon and currently 20kw of 48v battery. The inverter in using now is only 5.6kw. not enough. I will need to up size the battery to at least 50kw to make it worthwhile. I also have one victron rs450/100tr charge controller to start with.
I'll be going with 120mm2 cable and 300a nt2 blade fuse.
During any blackouts I can sell energy to the neighbours. At a free market rate of course😂
Excellent information of Solar system design
Thanks! 🙏
I am looking for a way to charge 4 different batteries at a time how do I start ? I am new to this and direction will be greatly appreciated Jim
you could buy his book..
Great information!
Excellent, Thank you so much!
Also, location of solar panels and distance from batteries, and the cables to connect them.
in regards to charge and discharge rates. is the charge rate a per hour measurement? 0.2c seems to me like it would drain a lead acid tubular battery to 50% in 5 hours. am i getting this correct or no? what if you need it to last you 24 hours? or 72?
C-rate is a current measurement based on the batteries capacity. 1C @100ah=100A. To answer your question: 12V * 100Ah = 1200Wh of stored energy, but you can only use 50%, so thats 600Wh. 0.2C of 100Ah is 20A at 12V= 240Wh. 600Wh/240Wh=2.5h running time.
Hi I have a 24V 240AH traction battery. Which converter can I connect to this and how many panels do I need at least to charge sufficiently?
Recommended to have a max of 1200W of inverter power (0.2C). Recommended solar panels is the same at 1200W to charge most efficiently.
@@cleversolarpower okay thanks. For you info.
very clear and direct.
Thanks, hope you learned something!
@@cleversolarpowerI'm curious, how did you arrive at 2/0 cable handling 250 amps?
@@powerguymark checkout welding cable by windynation on amazon
I have a question who inverter companies don't give a good answer, they said you can charge your battery bank with external generator connecting to your inverter charger, what kind of wave they don't say , pure shine or square or modify,I think only pure shine ,but most generators in the market still use square or modify.
There is a difference between inverter/generators and normal generators. The first have better sine waves, the latter have more 'dirty' power which not all inverters can take. I'm not aware of any inverters create a modified sine wave.
Very nice 👌 👍
Nice report👍
Good day sir,
I have 2 250W solar panels and one tall tubular 12v 240ah battery and a 30A charge controller,
I am using an egg incubator which runs 24/7 on AC 1000W inverter charger, my charge controller shows my usage 7A on average, sometimes it's not sufficient for my incubator and it turns off, so what could be the problem, please help on this regard.
7A*12V=84W*24h=2000Wh. you only bring in 1500Wh with 3 sunhours per day. Your battery is 2880Wh. You need to increase battery power and put more solar panels.
@@cleversolarpowerif I add one 12v 100ah battery, and connect a 250 solar panel to it without a charge controller for day time usage, will it be enough for day use?
And can a 250w solar panel charge my 12v 240ah battery alone for night use?
Will this setup work?
What about soldering cheap lugs???
Never solder lugs.
Hi @Cleversolarpower, this is Grandpa Emil, one of your avid subscribers in the Philippines.
Will it be possible to make a YT video about the proper way of charging and discharging powerstations? I am currently using a Pecron E1500LFP and since I pretty much would like to make the batteries last longer, I would want to know the proper way of charging/discharging/storing it.
There are several schools of thought on this matter which, instead of helping me, sadly, it made my brain explode:
(1) Some experts suggest to maintain at least 20% of its battery capacity before charging/topping it again for the next use. In relation to this, will it affect the one (1) cycle count if, say, I re-charge it back to 100% from 20% remaining viz zero percent because from what I've read, generally, a cycle is depleting the battery from 100% to 0%.
(2) On the other hand, some would advice to charge/top it to just around to 80% (not 100%) before its next use.
(3) Still, other experts would suggest that when storing LFP powerstaions, charge it between 40% to 50%. Then use it after 3 months of storage to maintain its battery life (roughly 3500+ battery cycles).
That said, based on your experience and hopefully thru actual tests concerning the same, can you please provide us in one of your future videos the proper way of charging/discharging/storing powerstations with LFP batteries or any other battery chemistry, for that matter? Thank you.
I recommend cycling a lithium battery from 10% to 90%. Normally you would program this in your charge controller and BMS of the battery. However, i don't think thats possible with power stations. Let's say your power stations battery can last 3500 cycles. That's still 10 years of use when you do one cycle every day. I think the electronics will die sooner than the battery itself. And after 3500 cycles you still have 80% capacity left. So don't worry about optimizing cycle life. Storage is around 30 to 50% charge, but again, that doesn't really matter.
Thanks you sir
melting cable, I learn this the hardway
😬
Seems most videos concentrate more on either 12v or 48v systems. A detailed 24v split phase system video for temporary home backup would be awesome.
12V only makes sense for use in an RTV.
24V has a big advantage: Sensors, plc etc. run on 24V. You will do hard finding components in industry quality for 12 or 48V, when building some sort of control system with a big battery backup.
48V is good for diy battery storage systems.
Why is it that everyone that does such explanations with using a 3000w inverter on 12v and suggesting cable size and fuses etc with the equation of 3000/12 fails to take into account that battery voltage when low or reaching BMS or inverter cut off may fall to 10v or even 9v. Cable, fuse, and even your 1.25 safety factor margin are out the window without taking the lower voltages into account. It's simple to say don't build such high powered 12v systems but there's situations such as in smaller recreational vehicles where 24v or 48v does not make sense.
He invested his time to make a video that is useful for certain people. He should be applauded. Nobody can satisfy everyone. If you have observed a gap in the knowledge, make a video about it and fill in the gap. That is why knowledge and learning are never ending.
@@1982757 I do applaud his knowledge and efforts. I asked a question and didn't receive an answer. I don't need to make a video or to have someone simping for him because you see my comment as a criticism. It has nothing to do with pleasing everyone. If voltage drops, amp draw increases. If you can't answer the question either then your comment is hardly useful.
Lithium batteries are 12V at 10% and 10V at 0%. If we use 10V as the worst case, then you will have 3000W/10V=300A. If we use 12V as the lowest reference, which was used in this video, we get: 3000W/12V=250A, multiplied by the safety factor of 1.25, we get 313A. This is still more than the 300A in the worst case scenario, so this passes. Your wire size and fuse size will both be larger than this. We will use a 2/0 cable which can carry 325A with a 300A fuse. Now you might think that a 300A fuse is too low. If we look at the datasheet, we can see that the fuse will never trip at 300A. Only at 525A after 16 minutes. Hope this answers your question.
@@cleversolarpower Thank you for your reply. You state that Lithium batteries are 10% when at 12v and 10v at 0%. I don't profess to be an expert and I'm learning more by asking questions, but surely that would only be true at a unloaded resting SOC voltage? Though lithium batteries are not as susceptible to extreme voltage sag under large continuous load as lead acid batteries are they still do suffer from it. Thus a 3000w inverter could run for some time at 10v 'if' the BMS or inverter cut off voltage is set that low. So, the battery voltage may be 10v but it's not truly at zero percent charge and without load it would recover to a higher voltage and the inverter would likely switch back on again. Which is one of the reasons voltage is far less useful as a guide to SOC with lithium compared to lead acid and shunts are more accurate. Also, with regards to cable size I would like to point out that despite standards (and here in Aus we use the B&S standard) not all cables sold from different manufacturers as a given size are created equal with regards to amp rating. Using generic data sheets rather than specific manufacturers data sheets for the brand of cable is asking for trouble. Then there's the reduction in current carrying capacity as ambient temp increases. Most cable ratings best figures are at say 25c. In a recreational vehicle traveling around in full summer inside temps can be double that.
1:39 @@cleversolarpower
Before watching this I thought I know solar system designing. How wrong I was. Roll up my sleeves
Voice like scott
Only use lugs that cost at least one dollar...
"I think I have an idea for profitability!" - knockoff amazon seller
Haha, they would get too much returns to be profitable 😄
Just a plug for a product, no thanks.