EVE vs. Winston? 60% price difference

[captianjuan]

what's the consensus from those with experience with one of both of these manufactures? I have a quote for EVE cells at about 1/3 the price of Winston cells. is the savings worth it? Is this one of those things that certain types of mariners can get carried away with having the best? I am about to decide on which to purchase. I would appreciate any insight from those of you in the know. thanks in advance.

[Emmalina]

Never heard of EVE but I generally mount CALB cells

[Anders]

EVE gets very good reviews at DIY Solar Forum.

[hjohnson]

Originally Posted by captianjuan

what's the consensus from those with experience with one of both of these manufactures? I have a quote for EVE cells at about 1/3 the price of Winston cells. is the savings worth it? Is this one of those things that certain types of mariners can get carried away with having the best? I am about to decide on which to purchase. I would appreciate any insight from those of you in the know. thanks in advance.

I built my pack with EvE cells, works well. But you have to be careful with your pack design with the aluminum cased prismatic cells. the plastic wrapping on them is tough, but not stupidly tough, and the aluminum shell is not electrically isolated. All the Winston cells I’ve seen are plastic shelled. It’s not insurmountable, you just have to be careful in your design. We made a compression fixture to hold the EvE cells and put tough plastic sheets between the pairs of cells as extra electrical insulation. We also took great pains to design the battery box so the cells would stay dry.

[PaulCrawhorn]

If you aren't fussed about maximizing longevity, Eve - if actually new, Grade A and tested before shipping - might be good enough for say a 7-10 year lifespan.

But more of a roll of the dice for sure.

Key ingredient is the vendor of course, best to buy from one reco here, and on the same continent as you.

[zstine]

seems that the manufactured batteries with BMS included have come way down in price and are available in 12V, 24V and 48V in many different capacities, and many with 5 year warranty. I have seen them as low a $260 for 100Ahr @ 12V (by USB i think). I don't think you can find cells anywhere near that cheap. And if you want high quality, there are plenty with certified Grade A cells with warranties that come in a nice case w/ BMS ready to go.



Is building your own battery really worth it?

[hjohnson]

Originally Posted by zstine

Is building your own battery really worth it?

In most cases, those “drop in” batteries won’t integrate into a larger system. They don’t have the circuitry, or communications hardware to properly control charging sources and/or loads. By building my own system, my BMS is in full control, commanding my solar, inverter/charger, and alternator as to what it wants in terms of voltage and/or current. In the past two months that the system has been running, the protection solenoids haven’t fired once.

The other problem with the drop ins is that they are prone to cascade failure if you put them in parallel. Sure, two 100A batteries are fine to drive a 180A inverter load, but if one pops for any reason, the other is going to pop too.

Lastly, most of the cheaper units don’t have low temperature cutoff/control. Might not be a big deal if you’re in San Diego, but for those of us further north, it’s a potential problem.

[Cpt Mark]

I built my batteries with Eve cells. These were brand new, grade A cells. There are a number of suppliers on Alibaba. It is important to find the right one. I have been very happy with this one.

Shenzhen Basen Technology Co., Ltd.
Contact Name: Alex Chen

https://www.alibaba.com/product-deta...5e702fc2DlAbYJ

If you've never built the battery before be aware that you will need to charge the cells up 100% first. Unless you have a really good, professional power supply this will take a long time. Don't try and shorten the process by using a std 12 volt car charger to get it close. Yeah, that didn't work so well in the end. Worked awesome in the beginning tho! . Also be absolutely sure you connect the pos/neg leads up correctly. That also didn't work so well. The smoke was kina cool tho lol

I see cheap 12v 100ah litho batteries for sale on Amazon now. Just have to wonder what's really inside them. Grade A cells, doubtful. Proper sized wires, connectors etc, doubtful. Only way to know is but one and cut it open. Will Prowse may have done a video on these by now. Buying the cells, you know what you are getting and putting inside your battery. You choose the bms for the same reason.

[Cpt Mark]

[QUOTE=PaulCrawhorn;3646318]If you aren't fussed about maximizing longevity, Eve - if actually new, Grade A and tested before shipping - might be good enough for say a 7-10 year lifespan.

But more of a roll of the dice for sure.

What are you basing your life expectancy predictions on? I am very curious to understand.

[hjohnson]

Originally Posted by Cpt Mark

If you've never built the battery before be aware that you will need to charge the cells up 100% first. Unless you have a really good, professional power supply this will take a long time. Don't try and shorten the process by using a std 12 volt car charger to get it close. Yeah, that didn't work so well in the end. Worked awesome in the beginning tho! . Also be absolutely sure you connect the pos/neg leads up correctly. That also didn't work so well. The smoke was kina cool tho lol.

Eh, top balancing isn’t strictly required if you have a good BMS and an integrated charging system. My REC ABMS has 2A balancing capability, and I just built my battery as is. As the battery approached full and the cell balance went out, it dropped the charge Current to 2A or so, and ran for a while and balanced all the cells. Since then, the cells have been within 0.003v.

[Cpt Mark]

Originally Posted by hjohnson

Eh, top balancing isn’t strictly required if you have a good BMS and an integrated charging system. My REC ABMS has 2A balancing capability, and I just built my battery as is. As the battery approached full and the cell balance went out, it dropped the charge Current to 2A or so, and ran for a while and balanced all the cells. Since then, the cells have been within 0.003v.

That's pretty cool.

[wholybee]

Some people (myself included) don't believe that you can actually buy grade A EVE cells. The grade A cells go to the EV market in China, and those that don't meet grade A spec are sold to secondary markets.

Quality can vary alot, depending on how the purchased cells failed to meet spec. It might be a negligible difference. It might be a significant difference that you won't notice for a few years, and the cells might have problems from day one.

However, there isn't really any proof one way or another if the cells being sold are grade A or B. Whatever you believe about them is hearsay. But for sure, some people buy "grade A" cells and get bloated and clearly damaged cells. And some people get cells that seem perfect (but haven't been cycled 1000 times yet so longevity is yet to be known).

I spent quite a bit more, and bought CALB cells, from a USA supplier. What I got was in a purpose built plywood shipping crate directly from CALB, with CALB factory test results included. There is no doubt the quality of what I bought.

[wholybee]

Originally Posted by hjohnson

Eh, top balancing isn’t strictly required if you have a good BMS and an integrated charging system. My REC ABMS has 2A balancing capability, and I just built my battery as is. As the battery approached full and the cell balance went out, it dropped the charge Current to 2A or so, and ran for a while and balanced all the cells. Since then, the cells have been within 0.003v.

The other side of this is that if you truly have matched grade A cells, and properly balance them, then no (or at most very minimal) balancing is needed. If you really ever need 2A of balancing, your cells are in really bad shape.

My CALB cells 2 years old and cycled daily are within 0.002v with only 10ma passive balancing in my BMS.

[hjohnson]

Originally Posted by wholybee

The other side of this is that if you truly have matched grade A cells, and properly balance them, then no (or at most very minimal) balancing is needed. If you really ever need 2A of balancing, your cells are in really bad shape.

My CALB cells 2 years old and cycled daily are within 0.002v with only 10ma passive balancing in my BMS.

Based on my observations, it only actually did any balancing on the first charge that I let it do. Since then the cells have stayed in good lockstep with each other. I’ve done a couple of heavy cycles on them to deliberately test things, and no issues. I’m running 230Ah EvE cells in a 2p4s configuration, and at most can do about 225A discharge on them. Worked quite nicely.

[goboatingnow]

Originally Posted by hjohnson

Based on my observations, it only actually did any balancing on the first charge that I let it do. Since then the cells have stayed in good lockstep with each other. I’ve done a couple of heavy cycles on them to deliberately test things, and no issues. I’m running 230Ah EvE cells in a 2p4s configuration, and at most can do about 225A discharge on them. Worked quite nicely.

This is my experience , after an initial test bench high precision balancing and the cells are exposed to fractional C charge and discharge , there is no need to subsequently balance , even if you do it can be a yearly thing done off the boat etc.