120V SISTEM install

[masbango]

Hi
Have inverter 48v vdc 120vac with a 60a mppt

also 16 pcs 3,2v 280ah lipo batterries (DOD 80%) and 4 pcs mono 500w panels

questions at what amp should the batt be charged?

should it be suffisient I have 2 refr inverter total 600w tv 200w and fan 75 w and the rest is some ledlight of 5, 7 w whit is total to 50w in the evening .

Hope it is clear and someone can answer me my question and suggestions.
thnks

Bob

 

[Rednecktek]

In good conditions you should see a bit over 40a. 2000w / 48v ~ 40a, little more.

 

[Hedges]

The cells would likely accept at least 100A charge.

BMS?

 

[masbango]

So I see as I have a 60amp mppt it is better to adjust to 40 amp.

But should a BMS works better in terms of balancing?

Appreciate
Bob

 

[Hedges]

You don't have to reduce setting of SCC to match what PV array can do.
If SCC and array are capable of more current than maximum allowed for battery, then you would set lower.


If you don't have a BMS, it is likely there will be catastrophic failure of some cells.
The BMS monitors each cell voltage, and disconnects if one goes higher than about 3.65V, or lower than 2.xx V.
BMS also performs some amount of balancing, during the time voltage is held in upper range.

Lead-acid doesn't need BMS. If a cell gets low, other cells go slightly higher voltage and start bubbling while low cell charges a bit. LiFePO4 and other lithium, if some cells are low then other cells charge higher and suddenly shoot up to 4V and even higher, causing damage, bloating, rupture.

Unless you like living dangerously, don't operate lithium without BMS.
If LiFePO4, over-charging causes release of flammable gas, which may get ignited.
(Some other lithium chemistry always vent with fire.)

 

[masbango]

thnks for the answer Hedges.

So I better dont use the mppt controller only rhe inverter charger?

as the mppt also control the pv input.

Please tel me what to combine in the system.

apppreciate

Bob

 

[Hedges]

Please list the model numbers of your equipment, and quantity of each. Including PV panels (how many), battery cells (how many), etc.

It can be fine to use a separate MPPT SCC in addition to inverter/charger. Many systems are built that way. Some systems have hybrid SCC/inverter/charger.

By the way, each PV array (or string) only goes to one device, not to both MPPT SCC and to a hybrid.
However, one battery can connect to multiple devices.

 

[masbango]

Hi Hedges
Have power inverter 48v vdc 120vac 4KW also separate controller MPPT

also 16 pcs 3,2v 280ah lipo batterries and 4 pcs mono 500w panels 48v

Have to hook up the pv cables on the MPPT .

But when using th BMS which I am going to buy JK brand smart Bms I think a 80amp or 100amp is sufficient.

New with this so how can I hook up the BMS with the MPPT?

as for pv cable I think 4 mm is ok as distance panel y to inverter mppt is about 18 meter apart

awaiting your reply

Bob

 

[Rednecktek]

Ok, so a note on nomenclature here. When you see a panel listed as a "12v" or "48v" panel, that's marketing speak for "I produce enough voltage to feed a 12v nominal system, but nothing higher" or "I produce enough voltage for a 48v or smaller nominal system, but nothing larger." So saying you have 12v or 48v panels really doesn't mean much. The key pieces of information we need are on the label on the back, specifically Voc (voltage ooen circuit for calculating how many can go in series before you fry an SCC), Vmp (working voltage under load) and Isc (max amperage under load). We'll need those.

Likewise saying you have an MPPT controller doesn't tell us anything. The difference between a Victron 150/100 and an EpEver 2060 is about the same difference between a Dodge Ram 3500 Super Duty and a Ford Maverick. Sure they're both trucks but that's about where the similarity ends.

Getting an aftermarket BMS to talk to a SCC is almost impossible. Don't worry about it, it's a luxury most of the time. As for the sizing, 48v × amp rating = max watts you can draw. If you use a 100a BMS you'll top out at about 4800w before you trip your battery. If you did an 80a (hard to find) you're likely to trip the battery before you trip the inverter. Bigger is usually better especially with larger cells.

 

[Hedges]

What Redneck said - need model numbers for everything. Links to data sheet would be good since it can be difficult for us to sort through the many models of some brands. Or list all the specs, but data sheet is best.