LiFePo Batteries: Build or Buy?

[Culwatty]

Originally Posted by newhaul

Not that as to retirement I tried but customers keep calling me and basically begging me to do work for them . Like a fool I said sure now 3 years on I can't get away from them

Its very hard to be irreplaceable! 😂😂 just do what I did. Charge more. Lots more!

[rgleason]

Ruixu Battery shows 12v
Lithium Iron Phosphate Battery 12v 100ah, Without BMS $559
Lithium Iron Phosphate Battery 12v 200ah,with BMS $1209
I think I need 200ah so this is more than I want to pay right now, but I can wait.


Will Prowse YouTube "$950 "Battle Born" Battery Tear Down" 12vdc 100ah
Excellent build, high quality materials, very solid case and much better than Ruixi similar version. Also has a low temp sensor. Uses 30 cells/rack x 4 racks=120 cylindrical #26650 cells. Each cell is 3.2v x 3.4 ah = 10.88wh x 120 cells = 1305wh which is more than the 1200wh advertized. The cells are larger than the standard 18650 cylindrical cells. So there really is a difference, compared to Riuxu construction.

[rgleason]

Looking at thread LFP Charge, Discharge, Storage vs Temperature
Post #1 and discussion following, with an interest in leaving the batteries in place (dependent on checking and making sure small solar panel works with resistance pads, to heat battery compartment).

Storage

• Below 20°C, warm slightly with solar resistance pads in compartment and thermostat that connects at drop below 20°C.
• 20-0°c (-4°F to 32°F) - no charge and no discharge

Charging

• 0-5°c (32-41°F) - very slow, less than 0.1C estimated
• 5-25°c (41-77°F) - slow, 0.3-0.4C default for longevity
• 25-30°c (77-86°F) - 0.6-0.8C charging
• 30-40°c (86-104°F) - 1-1.1C charging
• 40-45°c (32°F to 113°F) - back to 0.3-0.4c for longevity

Discharging

• 0-5°c (32-41°F) - very slow?
• 5-25°c (41-77°F) -slow? 0.3-0.4C?
• 25-40°c (86°-104°F) - .5C
• 40-45°c (32°F to 113°F) -?

I've done some interpretation here, but would be interested in having better facts about this question.


RI has 2-5 nights per year that reach 0F = -18C

[rgleason]

Regarding charging rate vs temperature see
See https://www.cruisersforum.com/forums...ml#post2994051

[rgleason]

Search for Camel LiFePo Batteries on Alibaba
3.2V90ah $20
3.2V 105AH $28
3.2V120Ah $36
3.2V152Ah $48

Newhaul are the above similar and the manufacturer of your 2p4s battery pack?

Interesting:
New graphene lithium iron phosphate battery 3.2V90Ah LiFePO4 10,000 cycles $28

[newhaul]

Originally Posted by rgleason

Search for Camel LiFePo Batteries on Alibaba
3.2V90ah $20
3.2V 105AH $28
3.2V120Ah $36
3.2V152Ah $48

Newhaul are the above similar and the manufacturer of your 2p4s battery pack?

Interesting:
New graphene lithium iron phosphate battery 3.2V90Ah LiFePO4 10,000 cycles $28

Yes but I used the 25ah units that I got for under 10 each delivered . I use it as a couple of 50ah portable packs now days

[Singularity]

Originally Posted by rgleason

3.2V 105AH $28

Interesting marketing strategy:

[rgleason]

Orient Power is another source that Will Prowse and JehuGarcia has covered.
They offer some interesting alternatives, including the blue cube with BMS.
https://www.youtube.com/results?sear...+power+battery

Look for 100AH Orient Power 12v LiFePO4 Battery Review

[rgleason]

Design your own Solar LiFePo Battery system

[Latecomer]

Originally Posted by newhaul

I went direct to the manufacturer i posted the specs uptrend as to the bms units . The company has an eBay site that has smaller units listed . Contacting them about your needs they will be more than happy to assist you.

https://www.ebay.com/str/shenzhenefiretechnology

And they accept PayPal

Great! Thanks.

[rgleason]

Here is another good source for BMS and batteries, suggested by Will Prowse
Steve from Overkill Solar Will tested these batteries, see his youtube on it.

[KPRick]

I work in boat building on the design side, specifically electrical. I am working with a company on an marine electrical propulsion system and have done a lot of work designing in Lithium Ion battery systems in high end sailboats.


For those of you who are not aware, ABYC released TE-13 Lithium Ion Batteries in July of this year. It took a long time to get here because it is a complicated topic. I can tell you that this is a work in progress and there will be changes coming. There are a lot of safety issues to consider. Unlike your electric car, you can't just stop on the side of the road and get out if there is an issue such as fire, and yes, fires do happen.


Part of what you are paying for with these "canned systems" is a small portion of the engineering time that went into making them as safe as they can today. If that has no value to you, then do what you will.



And this is not a "just change the batteries out" and make sure you have the systems in place that prevent over discharging, over charging and temperature limits to protect the batteries. The very low impedance of these battery systems means the potential short circuit currents can be considerably higher and that could mean the interrupt capacity of your primary over current protection could be well undersized by changing to lithium or even just a larger lead/acid bank. The charge acceptance profiles of these LI batteries can overheat and kill an alternator, even the best name brands (I have had extensive conversations with the engineering departments over the course of my work). Make sure you ask the alternator supplier if they would allow Lithium Ion battery charging service with your specific alternator. Of make sure that your voltage regulator will sense alternator temperature and reduce output to keep the alternator within the temperature range that will provide a good service life. Is the alternator drive and mounting bracket designed for the grueling service? Surprisingly, a number of the larger diesel OEMs warn against standard alternator brackets in LI systems. There are plenty more considerations, this is just the tip of the iceberg.



My point is not to scare, but to shine some light on the depth with which you need to look, consider and research before jumping in to this topic. I am sure that there are many readers of this forum capable of properly managing the risk, others not so much. Be smart and be careful.

[sail4evr]

I was very close to building my own for my boat. I had been reading everything online i could find. There is this guy with 100s of videos about buildng your own and he compares and reviews all sorts of related products.
https://www.bing.com/videos/search?q...tail&FORM=VIRE
It was during one of his videos that he made the statement if you needed waterproof, vibration proof, and there was one other thing, I have forgotten, he said buy something that is if you are on a boat or an RV. If you build your own likely it won't meet the test but would likely be all right for your house..
He rips open batteries to examine how they are constructed inside the case and he discarded many as unreliable. One of the batteries he opened was Battle Born by Dragonfly. After watching many videos of what he liked and didn't like and why he was exstatic about BattleBorn. Not to mention the only 10 year warranty out there. If you build your own you will likely get a 3 yr warranty from the cell manufacturer. I was realy excited to make my own battery, but realized to risk $4,000 on cells that might be losing a significant capacity after a few years and a BMS from China that also has a similar warranty I'd be kicking my self down the road if things didn't work out. Not to mention being in the middle of the ocean somewhere. If you are putting them in your house no problem, but going out to sea with family who are all relying on you. There is the saying penny wise and pound foolish. I was unfortunate in the batteries I was replacing were clearly near the end of their life and I couldn't wait until less expensive, more reliable battery cells or batteries came on the market. I put in the BattleBorn, tech support was outstanding and so far, 2 months, everything is wonderful.

[rgleason]

Dear KPRick

Thanks for the warning, but I don't believe any of the smaller builders of these batteries and battery packs are following standards at this point (maybe the expensive batteries like Lithionics, Victron, Trojan, Battleborn, Renogy etc) However even in these cases they keep the details about their batteries pretty much buried, except guys like Will Prowse provide a more detailed look at construction and practices.

Can you provide a link to that documentation please or is this some proprietary and "moving" standard that the common man has no access to, as is so often the case with ABYC? "TE-13 Lithium Ion Batteries"

Additionally, it should be noted that there are many users in this forum that know far more than ABYC about LiFePo4 Batteries. Furthermore I would not have a "Lithium Ion" House Battery on board as the technology for power tools is not as safe. Naming the document accordingly is another example of "total confusion for users" in my opinion.

Best Regards, Rick


Dear Sail44evr
Your choice was exactly right for you. Battleborn is good, I have seen Will Prowse's video. I don't think Chinese warranties are worth considering worth anything, but if the price difference is significant enough it might be worthwhile. $4000 or whatever buy a lot of boat repairs and equipment, so it would be quite dear to me, being a coastal sailor primarily. Rick

[rgleason]

Additionally, I intend to build a battery that is of good quality with a good reliable BMS and bluetooth, so that I can fit it into my boat inside the cabin, under the berth, and I know exactly how it is made and constructed. I would love to have Battleborn batteries, but I am not entirely sure they would fit, and they are way expensive.