now i dont get much?! BUT

[100kwh-hunter]

Having 3 * (16*280Ah) give me 7.7 kwh....in a field test.....7.7kwh....!
Wait what...3*16 cells*280ah...must be (48v*280ah=13,4kwh per 16 cells, each)..........times 3....40kwh? minimum
So 48 cells must give me ~40-45 kwh????
Three batterys of 48v 280Ah each.....
According to my calculations i must have a minimum of 35kwh?

My setting on my bmses (daly btw)
low v protect per cell: 3.000v
high v protect per cel: 3.300v
low total v: 48v
high total v: 53,6v

This is according? 80%DOD????So 6000 cycles aka 10 years of use?
80%dod would be a 230ah on 48v aka 8kwh?....per battery...and not 2.5kwh per battery

Question numb one; what means and what is basically DOD?
Number two; did i get my setting right?

My new settings:
low v protect per cell: 2.8v
high v protect per cell: 3.37
low total: 45v
high total: 54V

But com on....11.000 euro of cells..just 7.7 kwh....With the old settings? on 80%DOD
Did they dupe me?
Or where my settings wrong?
Daly is really a junkyard dog btw, dont fuck one inch or 2.5cm or ill bite....

Question numb one; what means and what is basically DOD?
Number two; did i get my setting right?

With best regards Igor

 

[SparkyJJO]

Your settings need redone.

At that voltage level you're not anywhere close to a full charge. 3.3V was waaay too low for high V protect. I'm not well versed on the "ideal" settings but you need to charge each cell higher than that. Heck my new cells came shipped at a higher voltage than that, and they're supposed to be shipped around 30%. So you're running your cells basically constantly near empty.

DOD is depth of discharge.

 

[100kwh-hunter]

This is half of my system would be

No i dont know how to handle a digital camera...

 

[100kwh-hunter]

DOD is depth of discharge.

This i understand?
But 10% below or 20% below or the other way around?
Or 10% below and 10% above?

3.3V was waaay too low for high V protect. I'm not well versed on the "ideal" settings but you need to charge each cell higher than tha

Can you give some advice on high and low? cells? and pack? this is not li ion.....2.8v to 4.2v 14s ....but lifepo4 16s..
Thanks in advance

 

[upnorthandpersonal]

Start by setting your high voltage disconnect at 3.55V per cell or so - 3.3V is nowhere near charged. Remember the charge curve:

Also, stop worrying about DOD as such. Put a high voltage protection at 3.55V, low voltage at 3.0V and call it a day. So for a 16s pack that's 56.8V at the high side, and 48V at the low side.

 

[sunshine_eggo]

3.2V * 48 * 280Ah = 43,008Wh

The BMS should never be relied upon for routine operations, i.e., it should be set for cell limits (2.5V discharge, 3.65V charge) and the equipment attached should be designed to operate inside the bounds of those limits, for example: 42V to 56.8V.

The wires connecting your batteries to your bus bars need to be all the same total length. If the total (-) + (+) cable length to the bottom battery is 8 feet, the middle and top battery should have 8 feet of cable. If you don't do this, the battery connected with the shortest cables will wear out before the others.

for a 10kW inverter, those wires look too thin.

Is each battery fused?

 

[100kwh-hunter]

My busbars are 300mm2 (*1,2A 360A rated)




The fuse per pack is 100A 48v dc rated.
The inverter has a 300A 48v dc rated fuse.



Those green yellow cables are 25mm2
So far so good?


The cables on the inverter are 3 times 16mm2, yes those are way to thin, when the inverter is going in full operation.
I ordered 2x 35mm2 red and 2x 35mm2 black with crimped lugs.
I also ordered 4 125A 125v dc switches.
Still need to connect the last 16 cells, so 4x16 x 280ah total for now.

All cables from the battery to busbare and bus to inverter and for the bms to the cells are all the same length.



Just two arrays are connected, solar cables are 6mm2 and 4mm2.
Those two arrays are going to be put together. there output will be max 80v 15A on a 15 meter cable.
The fuses are 125v 16A dc rated.

The next set of solar will be getting the same mm2 wire, 15 meter 90V and 15A(this set times two, a new mppt is needed)

All the bmses are set according to @upnorthandpersonal
The bmses are rated 100A discharge and 50 charge 48v dc.

Fun fact: when charging or discharging all the bmses act like one.

So i hope this will answer all your questions and will allow you to see or find some faulty/mistake things in my diy project.
I have no problem to take any advice and change or redo something in my project.
Sorry for the long story and i hope it was a good read in my best English.

With best regards and many thanks in advance,
Igor K

PS the black spot on the busbare was from charging the capacitor of the inverter.....i did not had any resistor....fun fact: the inverter has a soft precharge connection.....

 

[TacomaJoe]

Looks like the 100A fuse is between two cells. I would think that the added resistance would throw off the cell balance.

 

[upnorthandpersonal]

I would not use yellow/green - that's normally used for ground/earth.

 

[SparkyJJO]

A few things:
I would not put the fuse between cells. Put it on the outbound positive wire.
What interrupt current rating is that fuse? Some fuses will just arc over when they blow with LFP. Class T is considered the standard.

 

[wattmatters]

My setting on my bmses (daly btw)
low v protect per cell: 3.000v
high v protect per cel: 3.300v
low total v: 48v
high total v: 53,6v

It's little wonder you are only getting 7 kWh out of a 43 kWh battery.

Wrong BMS voltage settings and incorrect use of the BMS function. A BMS is there to protect a battery, not control the daily charging operation.

Increase the BMS protection settings to do what they are for, protect the battery.
Lower cutoff at 2.50 V/cell
Upper cutoff at 3.65 V/cell

Then set the charge controller to manage the upper voltage range for charging and the inverter to manage lower voltage level for shutting power down. The BMS is only there to cover the arse of either the charger controller or the inverter in case they fail to do their job.

At a minimum the bulk/absorb charge setting needs to be 3.45 V, and probably more like 3.50 - 3.55 V/cell.
Meanwhile you can tell the inverter to shut down if voltage falls below 3.00 V/cell.

 

[100kwh-hunter]

It's little wonder you are only getting 7 kWh out of a 43 kWh battery.

I dont think i get this one?
Is it a wonder that i get with settings 7kwh or
Should i get way more with those settings?

 

[TorC]

The former. If you look at the solid charge lines on the curve @upnorthandpersonal posted, even 3.37V is within the flat part of the charge curve, and it takes a long time to reach a near full charge when that's all you're driving the charge with. Given an ordinary solar day, you'll be very lucky to get 50% SoC out of it - and that probably only on an exceptional, long summer charge day, if ever.

 

[100kwh-hunter]

I would not put the fuse between cells. Put it on the outbound positive wire.
What interrupt current rating is that fuse? Some fuses will just arc over when they blow with LFP. Class T is considered the standard.

Class t was crossing my mind aswel, this one was advised to me from a store around here(no ali junk), more people tend to use this one according to them.
Agree, the arc is something to take in serious consideration.
I am waiting on some new breakers 125A fast dc, so i can switch it of and on when there is need for maintenance
Rated 12v-120v 125A breaking 4Kv, quick closing.
There is room(not much) to place them between the bus bar and the + cable.

I hope this is better?

 

[100kwh-hunter]

would not use yellow/green - that's normally used for ground/earth.

My uncle has his own scrap/old metal yard. this is what he had in 25mm2, but agree it should have been red and blue (and black between bms and batt.)

 

[wattmatters]

I dont think i get this one?
Is it a wonder that i get with settings 7kwh or
Should i get way more with those settings?

Figure of speech, presumably lost in translation.

Your charge settings are wrong. The battery will never charge up with such a low voltage ceiling. Increase the charge voltage to at least 3.45 V/cell, or higher perhaps 3.50 or 3.55 V/cell.

Then you will get your full battery capacity on discharge.

 

[100kwh-hunter]

The former. If you look at the solid charge lines on the curve @upnorthandpersonal posted, even 3.37V is within the flat part of the charge curve, and it takes a long time to reach a near full charge when that's all you're driving the charge with. Given an ordinary solar day, you'll be very lucky to get 50% SoC out of it - and that probably only on an exceptional, long summer charge day, if ever.

This chart i toke from this forum a couple of months ago was my guiding line:

​	​	​	​	16 cellen​	​
SOC​	Cell V​	​	SOC​	48V setup​	​
100.00%​	3650​	​	100.00%​	58400​	​
99.50%​	3450​	​	99.50%​	55200​	​
99.00%​	3375​	​	99.00%​	54000​	​
90.00%​	3350​	​	90.00%​	53600​	53600​
80.00%​	3325​	​	80.00%​	53200​	​
70.00%​	3300​	​	70.00%​	52800​	​
60.00%​	3275​	​	60.00%​	52400​	​
50.00%​	3263​	​	50.00%​	52200​	​
40.00%​	3250​	​	40.00%​	52000​	​
30.00%​	3225​	​	30.00%​	51600​	​
20.00%​	3200​	​	20.00%​	51200​	​
14.00%​	3150​	​	14.00%​	50400​	​
9.50%​	3000​	​	9.50%​	48000​	48​
5.00%​	2800​	​	5.00%​	44800​	​
0.00%​	2500​	​	0.00%​	40000​	​

Keeping in my head that 80% dod will give them a very long life, but 7.7kwh out of 43kwh....nah



So i think this is good?
The above is a screenshot from my pfone of the settings in dalybms.



I think i set the victrons correct also right now, sorry i could not let him turn to english language.
I think "druppel spanning" is float?.

Guys you are really great, all the help is really appreciated....
Many thanks in advance.

 

[100kwh-hunter]

Figure of speech, presumably lost in translation.

I had a feeling, but wanted to make sure

 

[littleharbor2]

I see no mention of your solar charging power but the 20 amp controllers seem a little small for this much battery. Can you describe your solar array, solar panel specs and how you have it wired?

 

[TorC]

Getting there on settings. That chart you based your old settings off of is deceiving in charge, because of the voltage delta required to push a charge into the cells. That's where UN&P's chart is such a nice demonstration.

You want your BMS OVP above the charger max voltage. Set that to 3.6V or 3.65V. Low voltage side looks like a decent conservative value. Victron settings look fine.