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Sinopoly 500ah Cells

Seawalker

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Nov 9, 2019
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I have been severely humbled by a battery buying mistake and now intend to build using Sinopoly cells. My PMAC motor draws 350a at full throttle and while I don't intend to use full throttle except in conditions of (high winds/fast current) I don't want to ever exceed Max Discharge Current. This puts me in the 400a 1C minimum. I would prefer 500a @ 1C.

I have found 500ah Sinopoly cells on Alibaba at a good price but would like to better understand how to ensure they are new grade A Sinopoly grade A and new. Has anyone purchased Sinopoly's in that size or could recommend decent vendors?
 
I want to point out that High Discharge cells capable of 3C are out there just for these sorts of applications. I came across them a while ago and considering the cost per cell, I kept moving along as such isn't needed in a residential / offgrid type of scenario. If you have a budget that can handle that you may want to search for High Discharge / High Rate cells, maybe even for curiosity just so you know your options. Sorry I haven't any links as that was quite some time ago.
 
Not a direct answer to your question, but you don't necessarily need 500Ah cells. You can just as well parallel 5 x 100Ah cells.
Yes, that's true but I have a space issue on the boat and so trying to find the right balance.
 
I want to point out that High Discharge cells capable of 3C are out there just for these sorts of applications. I came across them a while ago and considering the cost per cell, I kept moving along as such isn't needed in a residential / offgrid type of scenario. If you have a budget that can handle that you may want to search for High Discharge / High Rate cells, maybe even for curiosity just so you know your options. Sorry I haven't any links as that was quite some time ago.
Yes, I have seen these. However, the papers I've read that speak about discharge rates cast doubt on the ability of those batteries to deliver at 3C without shortening the cycle life. That is why I am leaning towards more depth and lower standard discharge. The Sinopoly 500a seems to be a good balance. I'm just hoping to get straight answers from the vendor.
 
@Seawalker .... About the only way to know for sure what you are getting is to find someone else who has bought from that vendor. I have some on the way that I am hoping are new cells ..... won't know for sure til they get here.
Maybe post the name of the vendor to see if anyone has had good or bad experience with them.

Do you mind telling us who you got the bad stuff from?
 
@Seawalker .... About the only way to know for sure what you are getting is to find someone else who has bought from that vendor.

If it was me I would want a report from someone who bought the exact same cells from the exact same vendor.
Unless this is a vendor that has established a good reputation.
Like Battleborn for example.
I'll let myself out :)
 
@Seawalker .... About the only way to know for sure what you are getting is to find someone else who has bought from that vendor. I have some on the way that I am hoping are new cells ..... won't know for sure til they get here.
Maybe post the name of the vendor to see if anyone has had good or bad experience with them.

Do you mind telling us who you got the bad stuff from?
The bad ones came from Shunbin bought through Amazon. 12v 400ah in a ss box. The constant current discharge spec was 300a. I didn't get past 286a before the BMS melted. Based on the BMS leads I'd say the BMS was likely 50a - 100a. The four batteries were wired in series. The one on the positive end was the one that fried.
 
If it was me I would want a report from someone who bought the exact same cells from the exact same vendor.
Unless this is a vendor that has established a good reputation.
Like Battleborn for example.
I'll let myself out :)
I'm now looking at CALB 400ah. The vendor has provided good documentation and has gone on record stating that they are new and balanced. Still not a guarantee but I trust the manufacturer as long as they are new.
 
I want to point out that High Discharge cells capable of 3C are out there just for these sorts of applications. I came across them a while ago and considering the cost per cell, I kept moving along as such isn't needed in a residential / offgrid type of scenario. If you have a budget that can handle that you may want to search for High Discharge / High Rate cells, maybe even for curiosity just so you know your options. Sorry I haven't any links as that was quite some time ago.
I have taken a 2nd look at the 400ah CALB and am getting more comfortable with that choice. The vendor has provided me with good documentation and I know from this group that CALB cells are respected.
 
I'm now looking at CALB 400ah. The vendor has provided good documentation and has gone on record stating that they are new and balanced. Still not a guarantee but I trust the manufacturer as long as they are new.

CALB is developing a good reputation.
What vendor?
 
The bad ones came from Shunbin bought through Amazon. 12v 400ah in a ss box. The constant current discharge spec was 300a. I didn't get past 286a before the BMS melted. Based on the BMS leads I'd say the BMS was likely 50a - 100a. The four batteries were wired in series. The one on the positive end was the one that fried.

With the Shunbin battery, are you sure the cells are bad. No need to throw out the cells if it is just a bad BMS.

Have you seen the posts form @Steve_S ? He replaced the Shunbin BMs with a Chargery BMs right out of the box. He also did other improvements to the battery.
 
With the Shunbin battery, are you sure the cells are bad. No need to throw out the cells if it is just a bad BMS.

Have you seen the posts form @Steve_S ? He replaced the Shunbin BMs with a Chargery BMs right out of the box. He also did other improvements to the battery.
Two of the cells completely shorted out and dumped electrolyte. I pulled the other BMS' and saw that the mosfets were damaged in those as well. I am trying to get a warrenty return.
 
With the Shunbin battery, are you sure the cells are bad. No need to throw out the cells if it is just a bad BMS.

Have you seen the posts form @Steve_S ? He replaced the Shunbin BMs with a Chargery BMs right out of the box. He also did other improvements to the battery.
That guy was smart. I did not realize the necessity of doing that. Now the damage is done. It may be worth replacing just those two cells. I need to ponder that seriously since Shunbin may not honor the warranty.
 
That guy was smart. I did not realize the necessity of doing that. Now the damage is done. It may be worth replacing just those two cells. I need to ponder that seriously since Shunbin may not honor the warranty.
There is a long thread, link in my sig, It appears they have pulled their ads out of Amazon.ca I haven't checked on amazon.com. I have some electronics background and when I saw the BMS I immediately knew I had to get that out of there, my 3 year old could have done a better job. Ugh, don't wanna think about it.

Please goto Amazon and REVIEW your issue with the blown BMS & two leaking sells. (photo's too) and I think they may be more inclined to resolve the issue, they did refund me $300 USD for their screw up which barely covered the cost of the repairs.

You can swap out cells BUT you'll need to match then up and that may be a challenge to get. MIne are AYOUPOWER 174AH which they discontinued (no longer listed on their site) and the closest they have is 180AH now and don't retail. You'll need to find out what the cells are by locating all the markings and searching them out on the web, QR codes "may" be helpful.

I'm prepping to building two more packs with Deligreens CATL 200AH cells, 2x 24v/200AH packs of 8 cells in series with BMS8T bms. Unfortunately the Chinese New Year shutdown tossed a wrench into those plans for the moment.
 
If this is the same Shunbin they are still on Amazon US and have an average 3.5/5 star rating!

 
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If this is the same Shunbin they are still on Amazon US and have an average 3.5/5 star rating!

Same bunch and some of the reviews on there are saying they aren't what they are billed as, as well...
 
So I just completed a conversation with Shunbin where they agreed to replace the two cells that blew out. However he completely ignored my argument that the BMS module was inadequate going so far as to show me a photo of an ammeter hooked to a different battery (12v 200ah) with a 300a readout which just irritated me even more. I wish I could say that getting the cells replaced made me feel better but I cannot. But I can at least get back on track with my project. A learning experience for sure.
 
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