No doubt series connections are the superior way to move power around with minimal losses. The point I am trying to make is that you will need to use extra effort to keep the individual batteries in a series connection closely matched together as time goes by and if you run your batteries up to or below 50% DoD routinely.
The problem with equalization in series is that to be successful, it assumes the batteries are still closely matched in capacity/performance - imagine a 50% discharged battery placed in series with an 80% discharged one in a 24v system - at full charge one battery is at 100% while the other is at 70% - equalization at high voltage for 4 hours would just boil the battery already at 100% and may not fully charge the one at 70%.
Hence I advocate isolating each battery and charging to full charge individually.
Shallow battery cyclers may never really push their battery to the limits hence they assume all is well - you would be surprised if you ran a capacity test on your batteries to find that they are all not of thesame capacity anymore
The above is why I love flooded batteries. The ability to send equalising voltage cross all the batteries in the bank forcing all the cells to get higher voltage charge until you ensure (with the help of an hydrometer) that their voltage has been brought to an equilibrium, the ability to do this once a month means battery will never be allowed to be stuck in voltage imbalance for a long time. If you use a Valve regulated battery than your best bet is a battery balancer.
And it is better to have batteries in series connections than parallel. Parallel connection are generally less efficient, more expensive to setup and are more prone to imbalance, even with the best battery to charge/load connection the different internal resistance of batteries are more pronounced with parallel than with series. With series connection you are dealing mostly with voltage imbalance, which can be dealt easily with battery balancer, with parallel imbalance is more current.. some batteries would do more of the work and get more of the charge (thanks to internal resistance) you can try to fix this using battery connection but it only mitigate the problem.
What I posted has been proven scientifically and not guess work. Recheck your physics or electrical theories. The net current is independent of the charge rate so long as there's a difference in current drawn and current put in. So no need to mention C10 or C20.
In retrospect, your assumptions is more of guess work.
I dont work with theories sir . . . especially those that don't apply to real life . .e.g
12v 100ah battery at 50% d.o.d on 30w load cumulative = 20 hrs backup
that is theory . . not correct in practical. . even if we adjust for losses in the system multiply by .80 inverter efficiency; still theory
even if you add battery peukert effect, still theory . .
the only way to know how long it would last, do a live demonstration and use a stopwatch !
so like i said; and still stand by, get two ammeters and do the measurement . . .
I am more concerned with the current hitting the terminals !
Publish all his phone no. Here pls. It is a very bad trend here. We have very honourable members here. We may invoke referrals through known forum members soon. Letz make Nija beta.
Lol, i dey observe all ooo. That Subomi guy ehn, i no really understand am ... even people don offer to help him dey reject help ... na so I waka ohhh
I was dismayed its same "infinitikoncept" i sent a fairly new mercury 3kva power inverter & batteries to few weeks ago.. The post has almost clocked 30 pages overnight
JUO: some people are just bad from the womb. imagine selling 40a epever cc to someone, after receiving it he decided he doesn't want it again. I refunded him only him swap the cc I sent him and sent me scrap/dead cc.
This is quite painful tho .. I just remembered your discussion with me few days ago but kindly mail me if you still interested in your request ! My instincts was right that fateful day but sorry for the loss ... Everything has its pros & cons as I duely select clients I do "pay on delivery" or "installmental payments" with . Hope you can now see the reasons why Mr XYZ did what he did that day via inspection of 80a mppt then ... It is well !
The above is why I love flooded batteries. The ability to send equalising voltage cross all the batteries in the bank forcing all the cells to get higher voltage charge until you ensure (with the help of an hydrometer) that their voltage has been brought to an equilibrium, the ability to do this once a month means battery will never be allowed to be stuck in voltage imbalance for a long time. If you use a Valve regulated battery than your best bet is a battery balancer.
And it is better to have batteries in series connections than parallel. Parallel connection are generally less efficient, more expensive to setup and are more prone to imbalance, even with the best battery to charge/load connection the different internal resistance of batteries are more pronounced with parallel than with series. With series connection you are dealing mostly with voltage imbalance, which can be dealt easily with battery balancer, with parallel imbalance is more current.. some batteries would do more of the work and get more of the charge (thanks to internal resistance) you can try to fix this using battery connection but it only mitigate the problem.
Hmmn, can we really do without parallel looping- connections ? Take for instance , George D 3 step 48v battery string connection which has been serving him well .. I also use same technique and my battery voltage are stable with very little differentials ...I might be wrong , but does your analysis also support 12 unit of 48v battery bank connected in series & parralel with equal sized cables ? Are battery cost the only reason why so many discard 96v inverters nowadays ?? I have seen so many battery balancer blow up or malfunction at various site for reasons I can't really phantom tho !
I understood Mr Niyi point as I have been using the same step on charging individual battery to MAX before hooking it up in strings & switching batteries by rearranging them for balancing sake too...Most installers might be lazy to do all this due to time & money factor but it works.. Untimely death of batteries really hurts for those who havnt been in such situation before ! Below is a snapshot on inspection & maintenance recently carried out on L16 flooded batteries corroded cabling, lubrication , PV array cleansing & electrolyte balancing as happy clients effects more customer referrals :
This assumption is wrong in theory and in practise. Electricity flows from high potential to low potential.
Scenario 1 If say your PV is producing 1000w and your load is using 1200w, 1000w goes from your CC to your load, and the reminder 200w is taken from the battery.
Scenario 2 If your battery is full and your PV can potentially produce 1000w and your load is 1000w, the load from the PV goes straight to the inverter (Your battery is completely ignored.)
Scenario 3 If your PV can potentially produce 1000w and your load is using 500w then 500w goes from PV to load and unused 500wh would become potentials.
Scenario 4 if your battery is low and your PV is producing 800w but your load is using 800w,all 800w produced by the PV goes to the load. Non is left for the battery.
Remember like I said, electricity moves from high potential to low potential.. The lowest potential in all the above scenario is the load, not the battery. The battery always has a higher potential than the load, The battery charger in this case the PV/CC has the highest potential (so long as we are using a proper charger with the right voltage)
Its just against physics for a battery to draw electricity more than the load. The above is the theory.
For the practical, I have a Victron Battery Monitor BMV 700 the BMV comes with a current shunt which is connected to negative of the battery, inverter DC input negative cable and Controller dc output negative cable. The positive cable of the BVM connects to the battery.
The BMV monitors currents going into and out of the battery from the Inverter and CC. The BMV display shows gross net input and output to the battery hence 1 if my charge controller shows it is producing 24A and my load is 10A, the victron battery monitor shows 14A going into the battery. and this is confirmed by the battery voltage.
If I turn off the 10A load, I see the BMV showing 24A going into the battery. If I turn off the CC, the BMV will show -10A being drawn from the battery.
If my load is say 24A and CC is pulling 20A, the BMV shows -4A leaving the battery.
This idea that all power from the cc first goes to the battery and the load pulls it from the battery is false and against the principle of how electricity works. when I have time over the weekend I will demonstrate the truth of this.
With your multiple inverters, do you have a COMMON NEUTRAL output AC wiring for all the loads connected to them? or does each inverter have its separate live and neutral wiring for their loads?
In my case the zinnox are wired in parallel with common neutral and phase - but they require a seprate parallel board plus communication cable between two inverters and current sharing cable
If the manufacturer has not clearly indicated if the inverters can paralleledled then NEVER parallel them even only neutral [font=Lucida Sans Unicode][/font]
In case of grid failure the neutrals will be floating and can cause circulating currents between inverters and all kinds of strange behaviours
NiyiOmoIyunade: You do bring a unique perspective to equipment/cable safety using breakers.
The three pole breaker you mentioned - is it dual rated to handle both AC & DC currents? If it is please share the brand names and specs.
I only break my inverter battery connection (60/100A DC MCB, Inverter AC charging input (32A MCB), Inverter ouput (6A or 10A or 16A.... AC MCB) as typical loads dictate.
In solar applications, I break only the solar input - I stopped breaking the CC to battery connection after I lost my 60A morningstar MPPT CC to an unexpected breaker trip one fine sunny afternoon like that - as I heard the loud bang and rushed to the balcony, I saw magic smoke, fire and brimstone coming out of the CC - IMMEDIATELY I STARTED HAVING A NASTY HEADACHE AS I CONTEMPLATED THE REPLACEMENT COST OF A NEW MORNINGSTAR CC.
It is very dangerous to do that if the CC really fails it can cause the whole battery to discharge through it at short circuit currents and will cause cables to catch fire.
You can always put cables rated at 1.5 the o/p current of CC and fuses so it will never trip unless really fault occurs ( the fuses trip only after 2 to 3 times of rated current and the characterstics is inverse)
NiyiOmoIyunade: I checked online and the Yohako MPPT CC appears to be rated at input VoC 96v and max current 80a - this is probably the reason why your installer used a 2 panels in series config for you.
The challenge is now that this controller is mismatched for your application as you are using a 48v nominal system. MPPT requires some 'voltage headroom' to operate properly e.g a 48v nominal system will charge batteries anywhere from 56v to 62v (allowing for desulfation voltages) - at the panel side you will need at least 90volts to give sufficient headroom for the Charge Controller to 'boost' current and realise MPPT benefits - with 24v nominal panels, you need a minimum of 3 panels in series to achieve a useable MPPT voltage range for a 48v nominal battery bank - unfortunately, you will fry the Yohako at this voltage level.
Its either you switch to a 24v inverter and keep the Yohako as is OR you set your panels as 3 in series and change to a different controller capable of at least 150vdc e.g Chinco EP Solar/Fangpusun or the venerable MorningStar or Midnite Solar, Magnum e.t.c
As it is now you have an MPPT CC but operating like or worse than a PWM because it is not suitable for your application
You still have to ensure your panels face either South or West or East (some folks on here do North but I have no idea how that works) in that order of preference, your panel mount tilt/angle is relatively flat, no shading on the panels, properly sized cables e.t.c to be sure you have captured all angles.
But clearly, it appears your issue is a poorly designed/mismatched system and you will need some tweaking to get it right.
72 Cell panels Typically 250 watt and above are higher Vmpp appox 34 to 37 V so it is enough to use two panels in series for 48 V battery . For sixty cell panels, it is better to use three panels for headroom
Infact a 72 V cell panel 3 in series you have nominal loss of 1-5 % of rated power due to conversion from higher volatge to lower volatge
Your analogy is seriously flawed because unlike a container, a battery has only 1 opening . . the same opening for inward and outward current . . . Current must flow to load first; and be replenished by solar array (when under load) Or no current flows to load, and current is received by solar array (when idle and charging) so when 30A flows to load, for example, and solar pumps in 40A back . . . current flowing into the "opening" is still 40A; (which will kill a typical 100Ah or even 200Ah battery over time) and not 10A Best bet is to increase battery bank You garrit ?
Gentlemen The battery terminals work like a DC busbar unless there is a real busbar. All this current exchange happens only in the terminals and only excess current ( +ve) goes INSIDE the battery for chemistry to charge the battery or if the load is higher than battery excess current is generated by chemistry and delivered to the load in addition to CC current
As long as the CC is maintaining higher voltage than battery the entire current will go to the load .
Now you can see the reason for Hybrid inverters like ipower/zinnox/gennex where the current going to the battery is limited by the inverter but Current produced by the CC can be directly consumed by the load as the busbar is formed inside the inverter. At one time i was running 400 AH bank ( max 40 amp charge setting) with 5 KW panels without any issues. Any excess load was automatically supplied by PV power
I do not like guesswork. Please place an ammeter between charge controller and battery bank; and let us know what you get, Then place between battery bank and inverter and let us know what you get too . . before you do this, please ensure the CC is supplying more than the c10 or c20 current thanks
all depends on how the circuit is wired is the inverter and charge controller paralleled before connecting to battery or both are connected to battery
see video of my installation https://www.youtube.com/watch?v=aZ7uu3_dLAc where you can clearly see the battery on the float with minimal current but PV charger( victron CC) still producing and supplying load The DC system in the video is ipower charge controller/inverter also contributing 250 watts for the load along with Victron charge controller
As you can see both CC are connected to 2.5 KW each but they are contributing just enough power to supply load while keeping batteries floating with out cooking the battries
NiyiOmoIyunade: Yes this is correct Boss. But you only have access to SG readings with flooded batteries and even then you go tire to dey check SG on a regular basis - all the hand flushing and equipment washing to rinse off the corrosive acid can become annoying
Again SG and voltage measurements are indicators that your state of charge is within a particular range. They cannot tell you the exact state of each cell e.g on my US battery L16 flooded bank I get temperature adjusted SG readings between 1.275 and 1.295 across all cells when my batteries are fully charged. Yet if I run say my 2hp AC for like 8 hours its the battery with one cell at 1.295 that collapses first
With all the charge in this world (my array can generate a max 75amps into a 360AH bank if I don't cap the output) I have not gotten the SGs to converge. In a moment of madness I even started siphoning electrolyte from the 1.295 cell into the weaker ones yet no joy
So I settled for simply clapping an individual charger on each battery on a regular basis and keeping the water topped up.
Flooded is good but as you would have seen from people's experiences on here with their Trojans and my own US Battery L16s, after a while things start to go south and they need ever more and more babysitting to keep them healthy.
As it stands now, I have given up on lead acid, our salvation now seems to be Lithium with the promise of negligible or zero sulfation/loss of capacity even at 80% depth of discharge.
I have considered it! But I have 8 pieces of 6v US Battery L16s connected in series to make a 48v system - it would be a wiring nightmare to set this up with balancers (at least I don't see a simple way to do it)
Also multiple balancers is multiple points of failure - without any load my PV array generates a steady peak of 85amps - imagine what would happen if any of the balancers failed during charge with 85amps coming from the panels when the CC has lost battery power and cannot open the FETs or otherwise invoke its protections. I once used the Sukam balancer long ago on my small 24v system with zero positive effect so it kinda made me believe this things are 'snake oil'
I need a low cost solution that I can reuse with clients - the balancers are a tad pricey and complicated to setup - periodic battery balancing with cheap 12v smart chargers is a useful service that we can bill for together with blowing dust off the inverter internals and putting dielectric grease on while retorquing battery and electrical connections for the client
70v PV input (just two 35vmp panels in series) to drive a 48v nominal system that will charge between 56 and 62volts is cutting it rather too close for MPPT.
Doubtless the system would charge but I am pretty sure it would not be deriving any MPPT benefits.
Very likely it would be working much like a suboptimal PWM system.
72 Cell panels Typically 250 watt and above are higher Vmpp appox 34 to 37 V so it is enough to use two panels in series for 48 V battery . For sixty cell panels, it is better to use three panels for headroom
Infact a 72 V cell panel 3 in series you have nominal loss of 1-5 % of rated power due to conversion from higher volatge to lower volatge
NiyiOmoIyunade: This is an interesting argument - much akin to three men feeling an elephant by touch and one who felt the sides decides the elephant is much like a wall, the one who felt the leg decides the elephant is like a tree while the guy who felt the tail decides the elephant is much like a rope.
I think it's all a matter of perspective but I will wait to see how things pan out.
. . . and the one who felt the tusk decided the elephant was much like a spear; while the one who felt the ears said the elephant was more like a fan
In my case the zinnox are wired in parallel with common neutral and phase - but they require a seprate parallel board plus communication cable between two inverters and current sharing cable
If the manufacturer has not clearly indicated if the inverters can paralleledled then NEVER parallel them even only neutral [font=Lucida Sans Unicode][/font]
In case of grid failure the neutrals will be floating and can cause circulating currents between inverters and all kinds of strange behaviours
House I need help. I have a diagnostics lab I support where the incoming voltage from the mains is routinely between 240v and 250v (the shopping complex has a dedicated and lightly loaded transformer).
Now we all know lab equipment generally have low overvoltage tolerance so the equipment gets hot or hums at 240v.
How can I reliably step down 240v to say 210 - 220v max? Most stabilizers I know will simply pass through 240v without stepping it down at all.
Right now the lab is getting by by isolating the mains (putting changeover in neutral) when they want to run the equipment and running off either inverter at 230v output or Gen at 217 - 222v output
Solutions and ideas please - if you know any stabilisers or other equipment that can cap output voltage at 220v I would appreciate it.
People that know me know I am more of a practical man .. i will post a video tomorrow concerning this; at least not to argue but for knowledge purposes
Pls hope am not the only one interested in the said video clip?
Thanks my man. This is exactly what I laboured to explain to makavele all through last night. He refused to accept that load can be used to divert current that otherwise would have ended up charging the battery above its optimum charging current.
This assumption is wrong in theory and in practise. Electricity flows from high potential to low potential.
Scenario 1 If say your PV is producing 1000w and your load is using 1200w, 1000w goes from your CC to your load, and the reminder 200w is taken from the battery.
Scenario 2 If your battery is full and your PV can potentially produce 1000w and your load is 1000w, the load from the PV goes straight to the inverter (Your battery is completely ignored.)
Scenario 3 If your PV can potentially produce 1000w and your load is using 500w then 500w goes from PV to load and unused 500wh would become potentials.
Scenario 4 if your battery is low and your PV is producing 800w but your load is using 800w,all 800w produced by the PV goes to the load. Non is left for the battery.
Remember like I said, electricity moves from high potential to low potential.. The lowest potential in all the above scenario is the load, not the battery. The battery always has a higher potential than the load, The battery charger in this case the PV/CC has the highest potential (so long as we are using a proper charger with the right voltage)
Its just against physics for a battery to draw electricity more than the load. The above is the theory.
For the practical, I have a Victron Battery Monitor BMV 700 the BMV comes with a current shunt which is connected to negative of the battery, inverter DC input negative cable and Controller dc output negative cable. The positive cable of the BVM connects to the battery.
The BMV monitors currents going into and out of the battery from the Inverter and CC. The BMV display shows gross net input and output to the battery hence 1 if my charge controller shows it is producing 24A and my load is 10A, the victron battery monitor shows 14A going into the battery. and this is confirmed by the battery voltage.
If I turn off the 10A load, I see the BMV showing 24A going into the battery. If I turn off the CC, the BMV will show -10A being drawn from the battery.
If my load is say 24A and CC is pulling 20A, the BMV shows -4A leaving the battery.
This idea that all power from the cc first goes to the battery and the load pulls it from the battery is false and against the principle of how electricity works. when I have time over the weekend I will demonstrate the truth of this.
Zeestone and I have this argument with every installation we do together.
He argues that all neutral is common even within the inverter internal circuitry and this is true.
Again, I note that the NEC retained the common neutral standard for backward compatibility though they do not encourage it - they recommend that the neutral bus/ wire be at least equal to or twice the size of the live wires.
When I look at the average household electrical distribution panel, one sees that all the neutral wires terminate on one bus bar and same for the earth/ground wires - so I have been forced to grudgingly accept his old-school method.
This is derailing from the issue in contention, which I believe bigrovar has setttled.
Even on this one. The theories as stated by the manufacturers would likely hold barring marketing gimmicks, as long as you hold the variables (temperature, pressure, load etc) precisely as stated by the the manufacturers. Manufacturer cannot state a test result at 25oC for instance and you do yours at 30oC and expect to get same result.
mank1234: This is derailing from the issue in contention, which I believe bigrovar has setttled.
Even on this one. The theories as stated by the manufacturers would likely hold barring marketing gimmicks, as long as you hold the variables (temperature, pressure, load etc) precisely as stated by the the manufacturers. Manufacturer cannot state a test result at 25oC for instance and you do yours at 30oC and expect to get same result.
Even with the same wiring, same temp . . . we would get different results .. you know why already thats why i said its theoritical .. only meant as guidelines . best believe, pranil put it to rest
Please out the person so that other dealers do not fall into the same trap