I decided to get a Seplos BMS which is one of the few DIY ones that will talk to my Sofar inverter (Sofar use the Pylontech CANbus protocol).

 

Found a suitable one on AliExpress.

 

$264 inc shipping isn't exactly cheap for a BMS but since it should be able to get better capacity out of my LiFePO4 cells by not treating them as lead-acid I decided to bite the bullet. It also included the LCD screen.

 

Ordered and paid on Saturday. 

 

Sunday I get a message from the AliExpress seller:-

 

 

Ouch!

 

I'm not paying $424 for a BMS! Order cancelled refund in progress.

 

Members on another solar-energy forum reported good results talking direct to Seplos so I contacted them via their website.

 

Return email very rapidly from "Henry" who was happy to sell me one unit (some Chinese manufacturers won't give you time of day for less than 100), the LCD plus an RS-485 to USB converter and FedEx(DAP) 5 day shipping to Thailand for a total of $191 including AliBaba 4% service charge.

 

I expect to pay VAT on the beast when it arrives but at 7% it won't break the bank.

 

Saving of $75 over the original order price!

 

 

Just got an SMS from FedEx, box is on the way, delivery Wednesday.

 

So it looks like Seplos' covid related stock issues (at least for bare BMS') are sorted ???? 

 

No indication (yet) from FedEx of any duty to be paid.

18 minutes ago, Crossy said:

No indication (yet) from FedEx of any duty to be paid.

Wait for it....!

17 minutes ago, Liverpool Lou said:

Wait for it....!

 

Yup, there will certainly be VAT, solar equipment is "supposed" to be zero for duty, we shall see.

 

I have no problem paying legitimate fees, it's part of importing stuff and my past dealings with FedEx have actually been ok.

I also have notice that the Aliexpress prices are more in line with retail prices for goods in Thailand which seems to be double what they are on Alibaba and Made-in-China. 

Buying direct from the manufacturer is generally possible but the "sample" price is somewhat higher than the 100 off price.

It has arrived, obviously rather under-declared as is standard practice.

 

Just VAT on the CIF plus the handling fee.

 

 

On 6/9/2022 at 2:24 PM, Crossy said:

I decided to get a Seplos BMS which is one of the few DIY ones that will talk to my Sofar inverter

Curiosity, being what it is, has me wondering why you want to change your BMS. Was the other one not working correctly?

4 minutes ago, Muhendis said:

Curiosity, being what it is, has me wondering why you want to change your BMS. Was the other one not working correctly?

 

The problem is with the Sofar inverters, there's a software issue that with no BMS comms they treat the pack as lead-acid (leading to a max charge of around 80% if you have LiFePO4) no matter what you actually set the parameters to. It's a known issue and Sofar are showing no interest in sorting it.

 

On 6/9/2022 at 2:24 PM, Crossy said:

Sofar use the Pylontech CANbus protocol).

 

I thought CANbus was for mobile applications like automobiles and aircraft

7 hours ago, Muhendis said:

I thought CANbus was for mobile applications like automobiles and aircraft

 

Yup, it was designed with mobile and other electrically noisy environments in mind, but it's finding its way into other areas of course.

 

https://en.wikipedia.org/wiki/CAN_bus

 

2 hours ago, Crossy said:

 

Yup, it was designed with mobile and other electrically noisy environments in mind, but it's finding its way into other areas of course.

 

https://en.wikipedia.org/wiki/CAN_bus

 

Looking around CANbus things I notice Arduino have some suitable modules. Maybe there is a way to translate from CANbus to 485. Not much good though unless the origin source code is known.