shagking:



5 X 4

ceaser:
Folks, I have actually gotten away with 150w x 6 (2s3p) 12v system on a 60A MPPT. That's clearly 180w above the allowable limit of 720w (12v system) for the CC.

Just curious if I may get away with 300w x 6 (3s2p) 24v system on the same type of CC. That'll be 360w above the allowable 1,440w (24v system) for the CC.

Please anyone who has done that without frying the CC. Wanna be sure it's practicable.

I know 2s is good, but I prefer 3s cos the vmax of the CC is 150v. I don't wanna do 250w panels either.

ceaser:
Folks, I have actually gotten away with 150w x 6 (2s3p) 12v system on a 60A MPPT. That's clearly 180w above the allowable limit of 720w (12v system) for the CC.

Just curious if I may get away with 300w x 6 (3s2p) 24v system on the same type of CC. That'll be 360w above the allowable 1,440w (24v system) for the CC.

Please anyone who has done that without frying the CC. Wanna be sure it's practicable.

I know 2s is good, but I prefer 3s cos the vmax of the CC is 150v. I don't wanna do 250w panels either.

mcTrinity:


Hi Ojtech,

First, you missed out quite some details.. You didn't specify if it's hybrid inverter or standalone.
I also want to assume that the battery bank is a combination of 12V 200Ah batteries connected in series.

You also didn't specify if the Inverter was actually outputting the 40A during the observation... Might be possible it's not. And also the quality of the Mains voltage

However, though it's new, how long it would take depends on the state of the battery.
I bought 8 set of Quanta Batteries last 2weeks for an installation. I put all through an independent pre-charge, which I normally do before installation. Each of them took between 8-10hrs to go from boost charge (@250-260W) to Float Charge (@30-35W). And yes, I monitor each using a Socket-plug wattmeter. Few of them were September 2019, while others were October. Been sitting in warehouse for quite a time, and I believe that's why they took that long to go through the charge stages... Otherwise, it usually take 3-5hrs

So, there are factors that could make it take that long. You could provide any other detail that might help

Lastly, I want to believe that those batteries are AGM or they are actually designed to handle such amount of charging current. 40A on a 200Ah Battery bank is quite big... That is if it's charging through Mains supply irrespective of whether there are powered loads or not

Cheers

essegis:
You know its DIY when na kpako we use hang home made bussbars

See wetin COVID-19 do a brother.

ojeysky:


My current felicity is 1.5kw but my array is 250w X 9 (3s3p) so you should be fine. Just make sure not to exceed the voltage rating of the CC.

essegis:


You can actually do this. The disadvantage is on you as the CC just wastes the excess power. It will not take more than what it will allow. Although baba, you no go even notice any loss joo.

One thing you should never try though is going above the allowed Voc. That is frying pan territory.

ceaser:
Folks, I have actually gotten away with 150w x 6 (2s3p) 12v system on a 60A MPPT. That's clearly 180w above the allowable limit of 720w (12v system) for the CC.

Just curious if I may get away with 300w x 6 (3s2p) 24v system on the same type of CC. That'll be 360w above the allowable 1,440w (24v system) for the CC.

Please anyone who has done that without frying the CC. Wanna be sure it's practicable.

I know 2s is good, but I prefer 3s cos the vmax of the CC is 150v. I don't wanna do 250w panels either.

NiyiOmoIyunade:

.........
Meanwhile I have a 19kw array that should go live next week - the array will feed multiple large loads and 40kwh of PylonTech storage - I should be in a position to post live system stats and pictures at that time.

I also have 60A MorningStar MPPT for sale - brand new in factory seal in case you are interested or Oga George wants a spare - despite the move in exchange rates, I will cut anyone who asks a sweet deal at the old market price

NiyiOmoIyunade:
Most properly designed MPPT CCs allow some degree of oversizing the PV array. This capability is not uniformly implemented amongst CCs e.g with EP Solar CCs there is a calculation that caps you at a certain size relative to battery voltage or such. With a MorningStar, you can actually oversize nearly infinitely. I have oversized 200% + with no trouble but at some point it becomes inefficient to keep adding more panels.

One thing I can tell you from experience is that the CC will run much hotter when you oversize and you are advised to incorporate a cooling fan or AC to preserve CC lifespan and performance (avoid CC limiting current when running too hot)

I currently have a 7.7Kw array on a Victron MPPT 250v/100A - effectively oversizing by more than 25%. The CC runs very much hotter than its brethren so I added external cooling.

Worthy of note also is the tolerance for errors reduces with an oversized array -- apart from VoC you should never exceed the CC's max short circuit current limit. If you do then you better, have connected things the right way around (no reverse polarity mistakes or battery disconnects at high wattage charging) else you will surely fry the CC and make a sweet smelling burnt offering to the Sun Goddess to atone for the error of your ways

essegis:


Nice. Exactly what I was telling him but in Queens English.

My question is why are you saying your Victron MPPT is over sized at 7700w when the spec sheet says 8900w for 48v system. I just bought one and working around the 8900w rating oo, abeg your answer will be appreciated. Thanks.

NiyiOmoIyunade:
My Oga.

The CC is capped at ~100amps battery output. I have a 48v battery system with max charge voltage set to 52.5volts ergo I can only process about 5,250watts of power through the CC per time despite having a 7.7kw array attached.

Benefit is that I see 80-90amps through the CC before 11am.

I still have the MorningStar CC for sale at 220K please - brand new MPPT 60A in factory packaging

essegis:


Baba, congratulations on your set up. Its not easy. My post has been modified as I have seen my mistake. No vex.

But you are not my friend anymore oo. Na friends like you make me go use ₦1m buy Victron when Chinco spoil trowey full market. See as Victron full one person wall nitori olorun.

Abeg make I come dey go before them go say my Ijebu spirit don start again oo.

ceaser:




Baba, I don already see am for your profile. I don know say you be culprit already. Lol.

NiyiOmoIyunade:
Me that I am envying your Lithium collection and thinking of how I can get some off you to play with

As an enthusiast you just want to keep trying out stuff.

My PylonTech source believes I still need another 20KwH to round out my system I just smile, he does not know that I had to sell one vital organ and plan for a long time to get the current set.

Any further spend na die be that o!

Your 1million plus is well spent. Buying trusted premium products, you will never have regrets - the reliability, performance and bells and whistles are well worth it. I used to think Fangpusun was alright until I started using Victron in my own house and saw it blow the Fang outta the water. Imagine trying to aggregate your total PV generation in one dashboard when the CC is Fangpusun or EPSolar

ojeysky:


Which the MK will do flawlessly coupled with emoncms and victron BMV you see fantastic stats for a quarter of the price. I love victron but na only if someone will dash me sha

NiyiOmoIyunade:
My Oga.

The CC is capped at ~100amps battery output. I have a 48v battery system with max charge voltage set to 52.5volts ergo I can only process about 5,250watts of power through the CC per time despite having a 7.7kw array attached.

Benefit is that I see 80-90amps through the CC before 11am.

To the second part of your question, you have/plan 8,900w mounted for a conventional 48v battery system charging between 56v to 59v, you can only process about 6000w through the CC - at peak power you have to consider that you have ~3kw of panels just sitting outside and cooking in the sun, they are contributing nothing to the house loads. To put it technically correct, such a huge PV array would never operate at the maximum efficiency possible.

Hence, it may make sense to buy a second smaller CC and move some of the array to it. 6kw PV on the MPPT 250v/100A and 3kw PV on say an MPPT 150v/45A seems like a sweet spot. You get max solar juice at all times and the CCs work less.

I sometimes struggle to justify a use case for the Victron MPPT 250v/100A because of the very high price The only reason I have one is that I bought and sold some surplus inventory that came at a 30% discount and then kept a few units for myself

I still have the MorningStar CC for sale at 220K please - brand new MPPT 60A in factory packaging

essegis:


Baba, congratulations on your set up. Its not easy. My post has been modified as I have seen my mistake. No vex.

But you are not my friend anymore oo. Na friends like you make me go use ₦1m buy Victron when Chinco spoil trowey full market. See as Victron full one person wall nitori olorun.

Abeg make I come dey go before them go say my Ijebu spirit don start again oo.

tonididdy:
Anytime and everyday I read this thread... I always get serious headaches.

... I dey look all of una like Einstein's

NiyiOmoIyunade:
Most properly designed MPPT CCs allow some degree of oversizing the PV array. This capability is not uniformly implemented amongst CCs e.g with EP Solar CCs there is a calculation that caps you at a certain size relative to battery voltage or such. With a MorningStar, you can actually oversize nearly infinitely. I have oversized 200% + with no trouble but at some point it becomes inefficient to keep adding more panels.

One thing I can tell you from experience is that the CC will run much hotter when you oversize and you are advised to incorporate a cooling fan or AC to preserve CC lifespan and performance (avoid CC limiting current when running too hot)

I currently have a 7.7Kw array on a Victron MPPT 250v/100A - effectively oversizing by more than 25%. The CC runs very much hotter than its brethren so I added external cooling.

Worthy of note also is the tolerance for errors reduces with an oversized array -- apart from VoC you should never exceed the CC's max short circuit current limit. If you do then you better, have connected things the right way around (no reverse polarity mistakes or battery disconnects at high wattage charging) else you will surely fry the CC and make a sweet smelling burnt offering to the Sun Goddess to atone for the error of your ways

bbally:
please house, I need some lecture/ insight on how to connect an Hybrid inverter or inverter with built-in charger to a separate pwm/mppt cc connected to solar and batteries without causing issues or fault to either the inverter or the cc.

will the current from the cc backflow to the inverter board and vis visa?
is it advisable to set the cc at 14v pv off to give preference to grid charging?
is there anything like charging overload?

NiyiOmoIyunade:


As an enthusiast you just want to keep trying out stuff.

My PylonTech source believes I still need another 20KwH to round out my system I just smile, he does not know that I had to sell one vital organ and plan for a long time to get the current set.

Any further spend na die be that o!

essegis:
Hello guys,

Anyone got any idea of how I can bottom balance my LiFePO4 cells? I don't know what takes 3.2v and no equipment to use and transfer its charge into another set of batteries. Any idea is welcome though.

Im sure sha if I check this house properly I will see my new box of resistors (though not the box type). And I don't know which exact amount to use to drain the bank appropriately. Any calculations for things like these?

See bank below.

Queed:


Hello essegis!
I think that I could be of help to you.

First, I would make a few assumptions and you can make modifications based on your particular setup.

Your setup is 24p-4s Yes

I assume each cell to be 2.2Ah Nah, 8ah

with 24p you have a total of 24 * 2.2 = 52.8Ah

I will assume a typical 10C discharge = 5.28A Is 10C not actually 528A?

I assume you are balancing @ 3.2v This is the nominal na, for the bottom balancing I'm thinking of 3v or a little less

Taking max deviations = 3.5v I don't understand this

Resistor value should be 3.5/5.28 = 0.66 ohms

Power of resistor 5.28* 5.28 *0.66 = 18.4W

Ok so those are the theories!

In practice, it would be better you use two 1ohm resistors, rated at least 15W each, connect in parallel.

I am still a bit confused on how you want to go about this, is that you intend on connecting the balancer manually? Or you have a circuit already to automate everything? On YouTube it's to parallel the cells and find a way to discharge them to your desired low voltage. My problem is the discharge as I wasn't able to get any equipment for that before the lockdown hit

What about active balancer? Have you thought about them? The are more effective and efficient, I could design design one for you based on your setup. Active balancer might be required when they come fully into service

korban3134:
Good day all

Please I'm a Newbie in this inverter thing...i need help with one or two issues I'm facing.

I had an inverter and 200ah battery installed in my apartment about 5months ago. Initially performance was 7hrs now it barely lasts upto 2hrs. I want to continue with this alternative power thing as I've had my fill of using generators but this is discouraging.

1. Please I need a battery/inverter "Load Chart Guide"

2. Any solutions,/ recommendations on a better quality battery are very welcome