Buying from China

[Daddy Tanuki]

10 + years off grid here in Canada and running my own solar outfit... what the heck do I know...
View attachment 190683

Well you are a Canadian Bacon eating hoser... so.... This is a joke don't take it so hard.

 

[sunshine_eggo]

awe you so mean!!! not against you Eggo. but a lot of folks put a lot of stock in David Poss and Will Prowse... might want to rethink that statement. just being honest.

I'm talking exclusively about trusting Chinese vendors. I don't. At this time, the only one I trust is Amy Wan/Luyuan due to 1) prior purchase experience, 2) consistently predominantly positive reputation with forum users and 3) a recent purchase experience (made questionable decisions late at night...).

I will still be testing the cells upon receipt.

 

[sunshine_eggo]

Well you are a Canadian Bacon eating hoser... so.... This is a joke don't take it so hard.

Strange Brew!

"I gotta take a leak so bad, I can taste it!"

 

[Partimewages]

I love the "Shock Therapy"!
I was just watching The Red Green Show over the weekend.
And I'm completely off topic!?????

 

[MajicDiver]

Buying from China is not all that bad if you have a good idea of what it is you are buying.

About 2 years ago I was getting the run around trying to buy the larger (11.4 kW) Growatt auto transformer from Signature Solar, tried talking to Renvu also, same runaround which may have been in part attributable to the scamdemic.
I had noticed a company calling itself Yutuo Sun Energy in china offering a 10kW auto transformer that looked like a copy of the Growatt product. Less than half the price of the Signature Solar price. Purchased it and got it about 3 weeks later - I’d been trying to talk to Signature Solar for a month but could get nothing but gibberish from them. The person at Yutuo answered every single question I had via email over night. With shipping the cost was a couple dollars cheaper that SS price.

It’s been in service since August, 2022, first as a portion of our home was off grid, now whole home.

I consider transformers to be very low tech and low risk of troubles. Looking at the guts it appears to be well built to an untrained eye.

I would not buy an inverter that way due to my perception of higher risk.

 

[threepets]

There are a few issues with Banks including racks.
The wiring of a Bank is actually quite picky and when it comes to Lithium Based batteries that are Millivolt & Millamp sensitive (unlike FLA Brute Force Tech) one must be cautious.

1) ALL Wires should be same AWG and same length (also same cable type). The SOK wires are fine to busbars.
2) The Common DC Bus wires (from main busbar to AIO/Inverter should also be exactly the same length and gauge. *1
3) (-) & (+) should be taken OFF the SOK Busbars (in this instance) from the opposite ends... IE (-) from the top & (+) from the bottom.
4) Wires must be kept together to reduce/prevent EM/RFI noise)

*1 Excluding any fuses/switches/breakers

Wire length resistance IS a factor, even 2" difference changes the overall flow.

Charging Profile is also critical. The Moderate Conservative approach rules reality. To push beyond the limits of the working voltage range always comes with subtle issues that get worse the longer the situation exists and can have other deleterious effects.

Bulk/Absorb: 55.2V - Absorb for 45 minutes (3.45vpc) (some call this boost)
Equalize: OFF
Float 55.0V (3.437vpc)
MIn Volts: 42.4V (2.650vpc)
Max Volts: 57.2V (3.575vpc)
Rebulk Voltage: 51.2V (3.200vpc)
End Amps: #.#A (Allows for full Saturation at set Float Voltage) When EndAmps/TailCurrent I reached, ABSORB flips to FLOAT
End Amps is calculated (100AH X 0.05 = 5A or 280AH X 0.05 = 14A.)
EndAmps = TailCurrent !
Coulumbic Efficiency / Battery Status Meter Efficiency for LFP = 99%.

This get's the bank charged to full with high amps (Constant Voltage/Constant Current) and then float (Constant Voltage/Variable Current) tops off so the cells are at 3.47Vpc.
* Do Not forget to adjust for Voltage Offsets between Actual Voltage @ Battery Terminal & at Solar Controller and at Inverter Terminals.

Very Special NOTE: Floating & Saturating to 3.437vpc, accounts for the Voltage Settling post Charge of any kind which actually brings the cells to just below 3.400Vpc.

Steve S , thankyou for sharing this information and taking the time to share in such detail. Very helpful.

 

[threepets]

There are a few issues with Banks including racks.
The wiring of a Bank is actually quite picky and when it comes to Lithium Based batteries that are Millivolt & Millamp sensitive (unlike FLA Brute Force Tech) one must be cautious.

1) ALL Wires should be same AWG and same length (also same cable type). The SOK wires are fine to busbars.
2) The Common DC Bus wires (from main busbar to AIO/Inverter should also be exactly the same length and gauge. *1
3) (-) & (+) should be taken OFF the SOK Busbars (in this instance) from the opposite ends... IE (-) from the top & (+) from the bottom.
4) Wires must be kept together to reduce/prevent EM/RFI noise)

*1 Excluding any fuses/switches/breakers

Wire length resistance IS a factor, even 2" difference changes the overall flow.

Charging Profile is also critical. The Moderate Conservative approach rules reality. To push beyond the limits of the working voltage range always comes with subtle issues that get worse the longer the situation exists and can have other deleterious effects.

Bulk/Absorb: 55.2V - Absorb for 45 minutes (3.45vpc) (some call this boost)
Equalize: OFF
Float 55.0V (3.437vpc)
MIn Volts: 42.4V (2.650vpc)
Max Volts: 57.2V (3.575vpc)
Rebulk Voltage: 51.2V (3.200vpc)
End Amps: #.#A (Allows for full Saturation at set Float Voltage) When EndAmps/TailCurrent I reached, ABSORB flips to FLOAT
End Amps is calculated (100AH X 0.05 = 5A or 280AH X 0.05 = 14A.)
EndAmps = TailCurrent !
Coulumbic Efficiency / Battery Status Meter Efficiency for LFP = 99%.

This get's the bank charged to full with high amps (Constant Voltage/Constant Current) and then float (Constant Voltage/Variable Current) tops off so the cells are at 3.47Vpc.
* Do Not forget to adjust for Voltage Offsets between Actual Voltage @ Battery Terminal & at Solar Controller and at Inverter Terminals.

Very Special NOTE: Floating & Saturating to 3.437vpc, accounts for the Voltage Settling post Charge of any kind which actually brings the cells to just below 3.400Vpc.

Can bolts like these be used to secure battery cables safely to a bus bar? Zinc over steel.