Obimind1:
Good day @ everyone in the house. I have 2*200ah battery on a 24v set up 1.4va inverter, which I have used for over 2years now. I'm planning on adding 2 more 200ah battery so that I can have a longer back up time. The present batteries are not doing bad presently but I'm scared of adding 2 more batteries to avoid one battery bank acting as a load on the other. How can I achieve this dream of having a longer back up time without having more problems at the end of the day? Ur suggestions are highly welcome.

iLoveTheSun:


You already know the answer and the reason why.
So, sell your old pair, and buy four new ones.
(There is a technical solution to the above problem: it's called Battery Balancer. But I will not discuss it here, because it is not cheap >300 USD and you need some good understanding how to wire it correctly.)

But honestly, if you have space on and access to your roof, I'd recommend that you invest your money in a solar panel and a solar charge controller. They will last longer than your lead-acid batteries. Good quality will last up to 25 years. Get a 20 or 30 Amps solar charge controller, and buy a single solar panel, later you can get a second one and then increase your battery capacity.

sunny regards,

Barezzi:

Oh I have voltage switches, relays, contactors...
They switch my backup loads to PHCN based on battery voltage.

I had plans to get a timer to knock off PHCN from 6am to 6pm. What then happens on cloudy days when production is low and consumption high and one of the voltage switches kicks in?

They'd switch to PHCN, but the timer would have already taken it offline!
Except for my booster pump, kitchen tools and Laundry, the backup loads sit comfortably south of 700w daily. Else they hover around 4kw.

So by mid morning, batteries are floating. Pv production gets throttled and wasted. I have thought of introducing a contactor to switch my main loads to inverter during the day once batteries hit absorb or float to maximise self consumption.

Or get a grid interactive inverter.(I get about 20 hours of PHCN daily) The new wahala would then be reconfiguration of my Pv array, and ac coupling with the magnum.

What I want is to maximise self consumption. Grid supply in my hood is very good. I get high estimated bills from them yet I have a multimillion naira RE system always on float!

Sorry for the long winded post, just waking up.

iLoveTheSun:
Oh, and profit in the report is too high. Solarcity is basically a financial leasing company. They grew and grew in order to go public. When going public there were many questions about their accounting books how to value all those solar systems in the books. So the fresh money could fill the holes

netotse:


can you connect your charge controller/inverter to a computer? if you can, a raspberry pi could be a cheap way of automating your set up to achieve all you've mentioned.

bigrovar:
Brothers. I need help/suppliers/suggestions for a 15KVA / 20 KVA inverter system. It is required for a High Performance computer setup that requires pick load of 9900Watt of power. This is meant for highly rated computational science research. High end (US, Europe ) product will be considered.

GeorgeD1:
skalamanga,

going back to my earlier example above, it even gets better when you think of solar as a means of continuos power supply and not just like a generator which you start and stop every now and then.
let's say you have a solar power system which supplies you steady power during the day and a back-up system that supplies you power all through the night, the difference between solar and generators becomes just staggering!
if i were to run my generator on a 24hr (or minimum of 12hrs) basis like i was using an inverter, here's what we'll be talking about:

let's rewind:
30ltrs in 1 wk of roughly 3 hrs use daily becomes: 40 litres in 12hrs or 80litrs in 24hrs.
we will stick with the 12hrs minimum use option.
40ltr/day becomes 1,200 litres/month
at the present pump price of 65naira/ltr, this becomes: 1,200*65=  78,000 naira per month.
in a year that amounts to: 78000*12 =  936,000 naira per year
assuming pump price remains the same (which will be virtually impossible), in 25yrs, this becomes:

936,000*25 =  23,400,000 naira.

here it is! if you were to run a 5ka petrol generator for at least 12hrs everyday, you'll end up spending about 23.4 million naira in 25yrs at the present pump price but as we all know, the pump price can never remain the same over that long a period.
now the big one: if you were to run that same generator for 24hrs everyday (which you can achieve with a solar power system) you will end up spending 2 times that amount in 25yrs:

46,800,000 naira!

for less than one-tenth of this amount, you can install a solar power system that gives you trouble free operation for over 25yrs!

now, who still says solar is expensive? 

edited

Barezzi:
Dunka, that 145Vp is too close to 150Vp!
This na just wet season, what happens when dry season reach?
Your cc will be damaged if that voltage level is breached!

Braaad:
@Kiekie1 Thank you for the prompt delivery of the solar panels, mounting rack and accessories...... I got them all in one piece down here in Akwa Ibom. You even sent the pieces that was left out in our last transaction . that shows you are really an honest man. If anyone needs panels and accessories delivered to him fast ...meet kiekie1. He delivers fast.

Upload of my installation will be coming soon

DUNKA:
wow. I thought that, the charge controller is designed with the ability to handle such variation, with + and - tolerances.

Kindly advise further

DUNKA:
wow. I thought that, the charge controller is designed with the ability to handle such variation, with + and - tolerances.

Kindly advise further

Barezzi:


There's a thread in here on stringing ur panels to at-least twice the battery voltage.
So you should have 2 panels in series or at most 3, whilst ensuring the Voc stays around 100Vdc...

Mine hovers around 90 to 100Vdc region, but goes lower under load.
Other users will share their experience.

See an old pic i took many moons ago... I'll post more when i get home.

kiekie1:


Hello bro,kindly change to 3x3 config cos 4x4 has its (HVD/OVD)disadvantages on sensitive mppt cc esp at dry sunny season . Thanks

kiekie1:


Hello bro,kindly change to 3x3 config cos 4x4 has its (HVD/OVD)disadvantages on sensitive mppt cc esp at dry sunny season . Thanks

Barezzi:
Dunka, that 145Vp is too close to 150Vp!
This na just wet season, what happens when dry season reach?
Your cc will be damaged if that voltage level is breached!