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Topband Navitas Prismatic at BH

That's both good and bad. I'm glad BH is doing the right thing and replacing your crushed cell! I've been trying to call them this morning and keep getting the busy signal ?
I have never gotten them on the phone, they did give a call back, but I feel their pain, email is the best way to reach them, pls put, DAMAGED or RETURN as prefix in your mail with order id.
 
This is what they posted in their group on Facebook:
"This has been happening a lot I agree. Especially with these batteries.
Unfortunately due to the massive amounts of orders we got in and the demand for people to get their orders preferably right away (thanks to Amazon) it puts a rush on the shipping department... causing us to move faster than we’d like to which leads to things like this happening.
Moving forward, because of our recent rise in damaged packages we are going to focus 100% of the efforts on packaging them safe and secure and not worrying as much about getting them to you instantaneously. Although in a perfect world we want to achieve speed and efficiency... it’s a work in progress.
We sincerely apologize to you and anyone else that received damaged top band cells or any other products...
You will get replacements and i will make sure they arrive to you the way they are when we ship them out."

Sounds like they're going to take care of everyone.
 
Been cycling these things:

Navitas01.png

These are 20A discharges and 20A charges. Charges are terminated at 3.65V and 2A. The lowest two involved at least a day's sit following the last charge. The X-axis is time rather than capacity, but the capacities have hardly varied.

Each discharge takes about 80 minutes, charges take about 85 minutes and there's a 5 minute rest between charges and discharges.

here's what a charge looks like:

1612894755613.png
 
Great data @snoobler - Wish I had the equipment to do controlled charging / discharging and logging. I've only been done a top balance and a couple of charge / discharge cycles, and checking the cell voltages for my own log. They are staying very tight.

Do you use a CBA IV, or something else for the discharge test?
 
These are RC based chargers with some trickery added to enable me to capture the log data via wifi.
 
BH has emailed me back and will be fixing the shipping damage and lost cells with replacements! I'm very happy to hear that we all will be taken care of! Now all I gotta do is get this wall built ?!


- Thank you BH for everything you do to support this community! -
 
I'm a newbie and stepped into the larger capacity batteries by purchasing 32 of these 25ah cells after building my own18650 battery packs and experimenting with complete assembled 12V 30ah lifepo batteries before. My idea is to build 2x 12V 100ah batteries (4S4P - see pic below) to be used parallel in my current "backup" solar setup (SCC 12V 40A MPPT with 1000W [2000W peak] inverter) but also to use it in my future "VAN" 24V setup when needed (connect it in series and use it with a 24V, 2000W[4000W peak} inverter)

Reading the proposed solution and diagram snoobler posted on 29Jan, 2021 I’m in doubt if I’m following the best path/setup. I will appreciate any advice on a way to achieve the aim (if possible) including which type of BMS will be best suited for the job. Thank you to all the contributors on the Forum. I learn a lot.4S4P.jpg
 
I'm a newbie and stepped into the larger capacity batteries by purchasing 32 of these 25ah cells after building my own18650 battery packs and experimenting with complete assembled 12V 30ah lifepo batteries before. My idea is to build 2x 12V 100ah batteries (4S4P - see pic below) to be used parallel in my current "backup" solar setup (SCC 12V 40A MPPT with 1000W [2000W peak] inverter) but also to use it in my future "VAN" 24V setup when needed (connect it in series and use it with a 24V, 2000W[4000W peak} inverter)

Reading the proposed solution and diagram snoobler posted on 29Jan, 2021 I’m in doubt if I’m following the best path/setup. I will appreciate any advice on a way to achieve the aim (if possible) including which type of BMS will be best suited for the job. Thank you to all the contributors on the Forum. I learn a lot.View attachment 36888

If you're using these Navitas cells, you're 4P4S with only one BMS, so your monster cells capable of 75A each are limited to whatever your BMS is limited to. My diagram was to maximize the output current of these cells by having a BMS with each 4S string.

1000W/12V = 83A. Your surge might violate that, but HF inverter have only short duration surge capabilities. A 120A Overkillsolar would probably do the trick.

Since you plan to series them in the future, you should build 2X 4P4S batteries, each with their own BMS. Use them in parallel until you are ready to reconfigure for 24V. This ensures you get even (and reduced) wear on all the cells. When you reconfigure for 24V, you'll still be limited to 120A, but that's 120A * 24V = 2880W - well above your normal run power. The Overkillsolar BMS have a very high surge and are pretty tolerant.
 
Snoobler The Overkillsolar BMS have 2 options. 10 or 8 gauge wires. When will it be more suitable to go for 8 gauge?
 
I didn't notice @Cdvan's question or @snoobler's response. The short answer is what @snoobler said: Go with 8awg. In general, it's better to err on the side off too large wire than too small. You can Google the NEC ampacity tables and check, but I believe that a single 8awg copper cable can carry 50A, so the two from the BMS can handle 100A (with lots of caveats from NEC). I think 10awg can only handle 35A or 40A (sorry - I should look it up). Granted it is a short cable, and the real burden will be on whatever you use to get from there to your battery / charger. This is a case where it is worth it to get the bigger cable as @snoobler suggests. It doesn't cost much more, so why not?
 
I'm using elastic bands to visualize the copper cell connections. The Yellow elastics are the series connections.
I'll be compressing (vice and hammer) 1/2" Class "L" copper tubing for the connections.
The BMS is "Smart" so I should be able to adjust settings as required.
WIP-01.png
 

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Reeftank, honestly I'm kinda in a similar boat as you. I bought them to do a bigger 48 volt battery. I've never had a raw cell battery and I might have gone alil overboard.? ?
Sure you don’t wanna sell me yours topand cells if you are still having second thoughts
 
Sure you don’t wanna sell me yours topand cells if you are still having second thoughts
Heck, seeing what people are paying for them on eBay I might list mine on there if I can't get more of them. I have 16 Lishen 272 on the way and might just order another 16. The plan for these was a 100ah battery for my dads connex box as well as an ebike and some small powerbanks. There are so many options with these little ones.
 
I bought 60 of these, but having second thoughts now. I have 660 watts of solar, I've been wanting a lfp battery for awhile now. I don't have any equipment to test them so if anyone could post their results of these cells I would greatly appreciate it. Concerns are I didn't realize I couldn't do 4s15p for 12v 375ah, and the max discharge of 2.00 volts.
If you want your money back I’ll gladly take them off your hands
 
Screenshot_20210303-230521~2.png

I'm still confused. I think she just looked at the old listing without checking dates. I really do not want to buy from ebay with the price gouging. Anyone else confirm? ?
 
A couple weeks ago, I signed up to be notified when these would be back in stock. I got a email today from BH that they are back. They are only selling them by the case, which is more than I originally wanted... So I ordered a case.

I'm building a 4s2p battery for a trolling motor setup on my kayak, building another 4s2p for my dad who wants to put a trolling motor on his paddleboat. and might build a 4s3p to use as a backup battery for a small battery powered inverter "generator"

That uses all but 2 of the 30 cells ordered.
 
A couple weeks ago, I signed up to be notified when these would be back in stock. I got a email today from BH that they are back. They are only selling them by the case, which is more than I originally wanted... So I ordered a case.

I'm building a 4s2p battery for a trolling motor setup on my kayak, building another 4s2p for my dad who wants to put a trolling motor on his paddleboat. and might build a 4s3p to use as a backup battery for a small battery powered inverter "generator"

That uses all but 2 of the 30 cells ordered.
I can no longer find them on their site. Do you have a link?
 
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