For Sale: Winston 700Ah lithium cells

[Drelen]

I bought a Balqon 700Ah 13 volt lithium battery, using Winston lithium cells, for my RV. One of the 4 cells became weak, shutting off the battery when it was still nearly fully charged. Balqon has gone out of business and I could not get a new 700Ah cell from Winston in China, so I had to buy a new lithium battery for $5000. I am selling my three good cells for $500 each to anyone who has a similar problem with their Winston 700Ah lithium battery. Each cell is 3.25 volts. I can meet a buyer. Will be heading north soon.

[talonawd91]

I would be interested. I have a similar issue. 3 good batteries and one that is weaker. Still for sale and where are you located?

-Jeff

[Drelen]

Sorry. Since I received no response to my offer to sell individual good cells, I rebuilt my Balqon battery, and am taking it to Mexico to work as a backup to my new LifeBlue 600Ah regular system, with an A/B battery switch so when my solar reached 100% I will switch systems. I have had some success charging just the one cell to bring it up lately, using more voltage than normal, up to 8V. Larry, at Starlight Solar said I could even use a 12V battery charger on the one cell, instead of the expensive charger I bought to charge the one cell. If you need to switch, I am very happy with my new LifeBlue 300Ah batteries that look like a 8D battery, but weigh half as much and have bluetooth to tell you the SOC, temp, amount charging or discharging, and condition.

[andyalford]

I was thinking of buying these type of batteries, but I am guessing that both of you guys would suggest not to do that?


Can you give an indication of how long it took before the cells started showing problems.



What do you think caused it?


Thanks for cautionary tale...

[Drelen]

It turns out that lithium batteries over 300Ah have problems. I am now using LifeBlue batteries I purchased from Larry at Starlight Solar in Yuma. They have bluetooth inside for easy monitoring, a clean outside with just two posts. Look like 8D batteries but half the weight. I am using 2 300Ah batteries. Love them. Great service from Larry too. Horrible service from Winston. Drake

[Drelen]

Three of my 700 Ah Winston cells are just fine. Only one is weak. I was told that cells over 300Ah can have the current go across the top of the cell, not using the whole cell. LifeBlue cells that I am using now have everything built inside, including Bluetooth. I can connect to my batteries with my phone and read SOC, temp, charge and discharge rate, and status of each cell. I would have sold my 3 good Winston cells, but there were no takers when I was in the US, and now I have it in Mexico as a backup. It still works, but a 50 amp draw for 15 minutes (electric refrigerator defrost) will cause my weak cell to shut the whole battery off.

[andyalford]

Originally Posted by Drelen

Three of my 700 Ah Winston cells are just fine. Only one is weak. I was told that cells over 300Ah can have the current go across the top of the cell, not using the whole cell. LifeBlue cells that I am using now have everything built inside, including Bluetooth. I can connect to my batteries with my phone and read SOC, temp, charge and discharge rate, and status of each cell. I would have sold my 3 good Winston cells, but there were no takers when I was in the US, and now I have it in Mexico as a backup. It still works, but a 50 amp draw for 15 minutes (electric refrigerator defrost) will cause my weak cell to shut the whole battery off.

Interesting. Can you remember the source, or do you have a link for the failure methods of cells over 300Ah? I am in direct contact with Winston/China right now, and would love to sent his to them.


I am guessing you bought yours from Balqon - a few other people have mentioned that their cells might have been from a cheap 'bad' batch? Perhaps factory rejects that were sold as good stock. Could that be an explanation?


Thanks for your feedback.

[john61ct]

Yes the maker of the cells is a necessary indicator of quality, but far from sufficient.

The Chinese military gets most of the top quality "A" level output, and other high-volume regular buyers with good testing equipment would get the rest, probably the better strata of "B & C" quality as well.

The leftovers get sold to those who resell in small lots to consumers, that market is so tiny hardlt rates quality attention from the maker itself.

QA rejects are also sold out the backdoor by production staff.

So the bona fides of intermediaries becomes critical.

Sources recommended by people you trust with the gear required to test shipments / batches for quality as they come in.

And / or the ability to do so yourself.

Shipping is so expensive, even if the seller is 100% honest by western marketplace standards,, the end user directly importing herself pretty much means even a wonderful iron-clad warranty is useless.

So a seller that is both trustworthy an located on the same continent as you is really what is required.

Which means they are going to have to eat the X% of shoddy lemons they buy.

Which of course along with much higher operating margins, means their retail pricing will always be **much** higher than the unproven seller sitting behind an eBay or Ali listing dropshipping from their (maybe shady) source in Shenzhen.

So yes, dealing direct with the manufacturer may be a better way to go if you're trying to buy on price, but just realize the huge cultural differences in business operations and market conditions over there makes success going that way a real roll of the dice.

I do believe that huge Ah cells may well have problems being installed on boats.

But I do not believe that malarkey about the size in itself making a difference as to their effectiveness.

https://www.victronenergy.com/blog/w...t_73438490.jpg

So many "experts" give false information, could be based on their own self-interest not just ignorance.

[mako]

If one had the opportunity to visit the factory or distributors directly, what would be the best way to test the battery before taking possession?

[CatNewBee]

Winston cells are usually just fine. As with any manufacturer, you can get a problem unit, but AFAIK most installations just perform for years flawlessly. Sometimes it is the user who wrecks the cell with an improper BMS or ignorance.

Winston is a large producer with a long track record and cell sizes up to 15000Ah, 700Ah is nothing unusual for them. It is the only manufacturer with stable high Ah cells on the market.

I am happy with mine 1000Ah cells so far, I guess the 700 is even easier to handle.

[john61ct]

Originally Posted by makobuilders

If one had the opportunity to visit the factory or distributors directly, what would be the best way to test the battery before taking possession?

No business could allow that.

You need to be ready to test soon after arrival.

A standardized CC load discharge test from a precise definition of 100% SoC, higher than you'd usually charge in normal use, down to say 2.99Vpc.

Not only to see if capacity is as promised, but more importantly that all the capacities of each of the cells being assembled into a given bank match each other as closely as possible.

Internal resistance at various SoC levels, voltage curve from under-load - and being charged - recovering back to at-rest voltage, if time allows, self-discharge rate, all these will indicate at least a relatively uniform batch, consistency and predictability being at least as important as absolute performance measures.

Sometimes the actual **weight** of supposedly identical cells will significantly vary!

But should not see such gross errors with the top makers like Winston/Thundersky/Voltronix, CALB, GBS, Sinopoly and A123 (now Lithium Werks / Valence / Super B)

Since Trojan selected K2 as OEM for their new LFP "Trillium" line, I may add them to the list as well in coming years.

[mako]

Originally Posted by john61ct

Posted by makobuilders: If one had the opportunity to visit the factory or distributors directly, what would be the best way to test the battery before taking possession?

Posted by John61ct: No business could allow that. You need to be ready to test soon after arrival.

So here's an interesting email I received from a lithium battery supplier in China, and I've asked them for a copy of the test results. It must be a large commercial vessel, because that is a lot of batteries in the photo and 72V is a weird voltage. You can see that after testing they are sealing the cases with epoxy or such.

"A New Zealand customer came to visit our factory and tested the LiFePO4 batteries last Friday, share the pictures with you, enjoy a good time with him. The batteries are 72V 50ah and they are used on motorboat."

[JuliaYu]

Some distributors stock batteries with mixed batch, coming from different time of period, which is not good for end users. And probably that's the reason your 4 cells have this issue...
Buying from stocked distributor may save time for communication and shipping, but this is one of the risk.
If you are not in a hurry, ordering from factory or from distributors who can support shipping directly from factory is a good choice.

[JuliaYu]

Originally Posted by makobuilders

So here's an interesting email I received from a lithium battery supplier in China, and I've asked them for a copy of the test results. It must be a large commercial vessel, because that is a lot of batteries in the photo and 72V is a weird voltage. You can see that after testing they are sealing the cases with epoxy or such.

"A New Zealand customer came to visit our factory and tested the LiFePO4 batteries last Friday, share the pictures with you, enjoy a good time with him. The batteries are 72V 50ah and they are used on motorboat."

I have no clue what is the guy doing in the first picture...
And don't expect high quality from such unorganized production line

[CatNewBee]

Originally Posted by JuliaYu

I have no clue what is the guy doing in the first picture...
And don't expect high quality from such unorganized production line

I would say flooded Lithium Iron Phosphate batteries. ;-)

My guess is, they connect the cells and then fill the box with epoxy or whatever to make a rigid block. Advantage is, the cells cannot expand, they are watertight sealed and mechanically fixed within the pack, no corrosion on the poles, no loosen bridges, tools falling on top cannot shortcut a cell.

Disadvantage is they will blow in an explosion if treated wrong, because they just flood everything including the pressure release vents on top, also heat dissipation may become a problem and you cannot repair a defective pack by replacing a bad cell or a bad module.

The lab looks very "promising" indeed. ;-)

I cannot see what type of cells they use, looks strange to me, maybe the flex-packs. I do like the high sophisticated circuit breaker glued on the outside of the box borrowed from a t-rail installation compartment, for sure the right device for a LFP battery. So my second guess is, this are boxes with flex packs 10Ah or 25Ah or 50Ah connected to 72V per pack (21 cells) and then sealed. The breaker will be around 32A or 40A, look like cheap AC house installation breaker, I am not aware of higher rated breakers of this type, there are DC variants too with arc suppression.