Guangzhou Demuda Optoelectronics Technical Co Ltd

Guangzhou Demuda Optoelectronics Technical Co Ltd

Buyer’s Nationality:

Guangzhou Demuda Optoelectronics Technical Co Ltd

Seller Website:

Seller Address:
no 18 , 19th Xiamao Industrial Zone, Baiyan District, , Guangzhou, Guandong, 510425, China

Initial contact with the supplier:
Online Supplier Directory

Type of product(s) being purchased:
12volt 100 amp/hour Lithium Battery

Value of the Purchase Order when the incident occurred:
1,001 to 3,000 USD

Destination market of order in question:
Australia/New Zealand

Type of Complaint(s):
contract violations, scams & other unethical activities

Stage of relationship with the supplier at the time of the incident:
Initial Order

User Experience:
I purchased 6 12v 100ah lithium battery from Oliver ( mr Jack Ye Manager.

I paid $400 each for these batteries included freight.

When they arrived, I put them all on to charge, however 1 of them never too a charge and the green light indicated that the battery was full. But that was not the case.

After contacting Oliver at least a dozen times & Jack Ye , the best I ever got was ” when you buy more batteries from us, I will send parts to fix ”

What ever happened to the 2 year warranty?

User Recommendations:
Do not trust any china sellers.


6 comments on “Guangzhou Demuda Optoelectronics Technical Co Ltd

  1. Yes this company is very corrupted. The label all their batteries may be duplicate the real capacity.
    For sample, If is 50 ah, they call it 100ah
    then the one they call 200Ah it is actually about 80ah.
    Also they offer warranty of 2 years, But they will not replace any bad battery.
    We purchase orders of 12 each time, planing to buy 100, then, one entire batch was bad, The test results was about 40ah when they sold to us as 200ah. Then they did not replace anything.
    Someone told me I was lucky we did not place the big order of 100, because what they do, they don’t sent you the big order, They still you, That is what a Chinese guy from weihai explained to me.

  2. I would not recommend buying a battery pack from Demuda because of the mismatch between what you may think the capacity is and what it actually is. I ordered a DMD-200AH/G and the contract clearly says 200AH on it which implies 200 Amp hours of capacity. For a 12V system this would mean a max capacity of 2400 Watt hours. My multiple tests achieved 75Ah or about around 850 Watt hours. Due to the use of a BMS I would not have expected 2400 Watt hours. I would have been happy at 80% or 1900 Watt hours.
    What was most painful is I feel the pack works properly it simply has less capacity as advertised. The BMS clearly protects on the charging side even when I used my own custom charger. It also clearly protects on the discharging as it cuts out on its own when using 12V DC items without an inverter.
    I was very patient and did not show any emotion in my communication to the company. I was trying to help them because at 850 Watt hours and using a cheap inverter the pack crushes similar packs available on Amazon. I tried and tried to extract from Sam Liu the details of the Lithium NMC cells but he would not let me know. I contact Jack Ye but no response. I stated to them that I wasn’t looking for a refund I just wanted the truth. They are not willing to be truthful so I cannot recommend doing business with them. I have issued a complaint on Alibaba but as they got me to go around the Alibaba trade process (my bad) by sending money directly to them I don’t really have any power to shake them. I feel bad for people who will buy from them and not know how to test capacity. Luckily I have had good experiences getting products from Alibaba but I will do more research on the company going forward. I should have found this site before buying my DMD-200AH. The one comment about the capacity not matching would have saved me. I hope this comment saves someone else from disappointment.

  3. Hello everyone who was ripped off by alibaba and their criminal friends !!
    I wish that too! In december 2017 I paid 1633$ at

    Guangzhou Demuda Optoelectronics Technology Co., LTD
    Address: NO.18,19th Xiamao Industrial Zone, Baiyun District, Guangzhou, Guangdong, China
    Zip Code: 510425

    for two pure sine wave inverter 12V to 220VAC and four Batteries 12V 200Ah.

    My contacts were Jack Ye and Sam Liu.
    First, they sent me two wrong inverters. Instead of 12V / 500W (pure sine wave -> 40$/pcs) I got two inverter 12V / 500W (modified sine wave -> 10$/pcs!!). On the note that the wrong inverter were delivered, one has only replied that the ordered inverter at the time was not in stock!?!?? What? Then just deliver the wrong ones? I have not gotten the batteries until today! I’m trying to get my money back months now. The alibaba complaint management protects the criminals and does nothing !! All complaints are closed after a few meaningless e-mails again without results!! I am completely ignored by sam and Jack now. it’s just rip off by Alibaba and Co!! Definitely not trust this company and not Alibaba !!!!

  4. Thanks for the review. I wish I’d read this before buying a battery from these guys. I also paid $400 for a 12V 100AH battery. Mine worked okay but I checked the capacity and it was only 19AH. Very disappointed and ripped off.
    I asked them to refund me the money that I spent but once they knew I wanted a refund they stopped replying to my emails.
    Definitely do not trust this company.

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