₦airaland Forum

chris81964:
We have a US 2000 that exploded at one of our customer installations. The getting hot and failing is so common with the US Battery. A more than 25% failure rate. I have yet to have any issues with the Trojan L16 and I have a few that have been abused. I will not recommend US Battery. The factory gives you some BS and blame the user. I told them that real life experience trumps whatever they can replicate in the lab.

kiekie1:
Good point Sir ! I sure know of two modes which we have here...;
>>New feature "Likers association of Nairaland" LAN
>>"Discreet observers association of Nairaland" DOAN

chris81964:
We have the Tesla smart running.
Solar priority. The client has his swimming pool pump, water pump, household appliances and a hot water heater on it.
They average between 1500 and 2300 watts in consumption. This gives them about 3 to 4 hours with no solar power.
We have not installed our BMS yet so we have limited our capacity to a little over 5kwh.
We have 3080 w in PV installed. We will be adding additional PV. The generator is set up as a resource. The system starts and stops it, to meet battery or load conditions. Enjoy.

NiyiOmoIyunade:
Boss! With your declarations you appear to already have the answers you need na. Wetin u wan make I talk again?

Every so often this debate about how to evaluate power, energy, amps and volts comes up in RE forums so it is good to establish an accurate reference.

Here goes... assuming all devices are 100% efficient and can achieve their nameplate rating and all devices produce or take or give power at the nominal voltages......

Imagine you are helping a client build his solar system, you help him purchase 4 units of 250w 24v panels. How would you describe that system regardless of your ultimate panel arrangement whether series or parallel? I would call it a 1kW PV array.

Now if I arranged all four panels in series does the array become a 250w 96v array? . For me it is still a 1kW PV array operating at 96v. If I arranged all four panels in parallel, the array still remains a 1kW PV array but now operating at 24v.

What can we conclude from the above?

The total power in a system always adds up same as the energy always accumulates, however, inefficient design may lead to power and energy losses. In series the voltages add up but the Amps do not ( they either stay constant/common or take on the least Amperage in the system) e.g in our reference 1kW PV array, each 250w 24v panel produces approx. 10Amps (remember my earlier simplifying assumptions) when you stack the 4 panels in series to make 1KW at 96v, the whole system still produces approx 10Amps but at a higher voltage potential of 96v.

In parallel, the voltage does not add up but the Amps do so each 250w 24v panel produces approx. 10Amps but the entire 1KW system produces approx. 40Amps at 24volts.

So there it is. What do you think? I will let other folks in the house contribute too.

richmon74:
Cool.

It's nice to know that people on these thread are venturing into the DIY POWERWALL.

For your rack, what is your plans for cooling as I didn't see vents nor cooling fans provisions there?

richmon74:
Goodnews No. 2

We will be bringing in Trojan Lithium Ion battery for your peace with battery.

The good news with this is the fact that you wouldn't need to change your inverters and CCs as the Trojan Lithium will come with internal BMS (which victron lacks) which will be good enough for DIY guys as you wouldn't need to crack your head on rigorous configurations.

So guys, the renewable energy have come to stay and the technological advancement is coming closer to you.

I just hope most of us will get an opportunity to experience the efficiency of Lithium Ion batteries before the Graphene battery wipes it out.

NiyiOmoIyunade:
My Oga.

The best way to look at this is to think of the total power in the system. I will assume the panels are operating at their nominal voltages 12v and 24v respectively and that you can also access the 100% rated power of the panels and CC is 100% efficient too and finally that a 12v battery charges at a constant 12v

2 units of 12v 200w solar panels in series will give you 400w at 24v. PV side current is 16.66a at 24v while passing it through an MPPT CC attached to a 12v battery you get 2 times the current at the battery side so 33.33a but same power/wattage of 400w

1 unit 200w 24v panel will give 8.33a at the PV side and 16.66a at the 12v battery side using an MPPT CC.

In a PWM setting charging a 12v battery, you will lose half of the power when you have two panels in series to make 400w 24v since the PWM cannot convert excess voltage to useful current but if charging a 24v battery bank you can pass through the entire 400w.

Those are my thoughts at a high level. I could be wrong. Please let me know what you think too.

dgr8truth:
The battery cabinet for my DIY powerwall is now completed and in full use.

The next project is building the remaining 43000 kilowatts hours pack. It will be a real challenging project.

GeorgeD1:
niyi,
you're very much on point. sometime last year i did a review on tristar vs midnite cc. the midnite won narowly but just.
recall that the winning points were mostly on aesthetics/effizy and not necessarily on core performance.
if i were to do the same review today, having now being weaned off the grip of that glamorous looking midnite lady,
the morningstar cc would win hands down

p.s: by the way, i have since reverted back to morningstar. solid state all the way!

cool318:
Oga, do you have the time to look into Laptop Lithium-ion batteries, I have one I opened up, but can't source for the match able batteries, the clipping and the balancing. 18.5v

kiekie1:
Kai! Haba!! I go soon start dey charge you under copyright rules James .. Anyways make I pity you as you be my Brother sha !

NiyiOmoIyunade:
A 200w 12v panel and 200w 24v panel will produce approximately thesame amount of power - however all things being equal the current flowing through the 12v panel will be about twice that of the 24v panel - hence you will need thicker gauge cable e.t.c with the 12v panel.

What you want is more power delivered in the most economically feasible way (think higher voltages and thinner [therefore cheaper] wires and less losses) so if you have to choose then always go for the 24v 200w panel over 12v 200w except your specific system design requires a 12v panel

DMerciful:
Get inexpensive BMS from aliexpress even the ones with Bluetooth such that you can monitor system performance up-to individual strings on your android phone

dgr8truth:
I'm going the route of DIY powerwall, and thus far I'm pretty impress with the result.
It's a 7s100p setup of 190ah. I intend to crank it up to maybe 7s 300p/400p.

The lowest cells are 1500mah and the highest cell is 2500+mah.

I used repackr.com to group the cell

hisenjos:
Just got this Chevrolet Volt battery in.
16kwh total running at 360v.
Very heavy unit -over 200kg
Going to break it down to 48v and 24v units to use.
Will try and post pictures when it is done.

chris81964:
Thank you sir.
1. I am waiting for a batrium BMS.
Till it comes we will limit the max charge and discharge to between .5 and 1 V above the max discharge and one volt below the max charge.

2. Victron Quattro
I salute people who will work with individual 18650 cells. I lack the patience or ability to do what you do. This battery already comes with everything in it including an internal BMS.

totalgreen01:
Very Nice to see a move to 18650's

one of the best battery available....

may i ask some questions?

1. how do u plan to balance the battery pack?

2. what inveter are u using it on?


i have been working with 18650's for a while now.


thanks

chris81964:
They are finally here. #Tesla Smart Lithium Ion. They will be installed this week

tundebabzy:
Broken link alert

mank1234:
@ kiekie1: how much do you sell programmable timer socket and DIN programmable timer switch pictured below.

GeorgeD1:
dmerciful,

midnitesolar dc breakers or disconnects are arguably the gold standard in solar pv breakers.
they may be a little expensive but over time you'll get better value for your money.
while there may be other cheaper alternatives which go by different names, its always better
to stick with tested brands which have proven themselves with time.
in renewables, we should be careful not to sacrifice quality on the alter of low cost
alternatives which do disappoint when needed most.

http://www.midnitesolar.com/productPhoto.php?product_ID=183&productCatName=BREAKERS&productCat_ID=16&sortOrder=16