LiFePO4 - The future for off-grid battery banks?

[microvast]

Microvast -Lifepo4 manufacturer

Microvast is US-ventured manufacturer of Lithium ion battery cell and battery pack. Our production base is in China,headquarter in Texas USA. With outstanding skill and experience, Microvast can offer kinds of power solutions for power tools, E-bike, E-scooter, E-motorcycle, Electric car (EV/HEV/PHEV), Energy storage syste.Our products main in Lifepo4, NCM and LTO battery.

We produce cylindrical 18650 and 26650 Lifepo4 cells. By form cells into large module and pack with BMS, we have developed lot projects with our clients around world. Also we are the first large-scale industrial level LTO battery producer in the world. Our NCM 18650 cell is lowest iner impedance which can bear 15C discharge rate.

please visite our website for more infomation:
microvast.com


Moderator note, if you wish to advertise, contact user JASON.

[Reidec]

I do have a pick up truck but prefer to avoid a heavy item. Even more the reason to stick with the LFP. Building my first panel in the next couple days it'll be a 18v 3.7AH poly panel. I'm thinking I'll end up using a 18v 6AH mono panel to actually charge this project though. Any recommendations on what to do with my little 60 watt panel? Should I avoid connecting the 2 panels in parallel due to the different materials? In all actuality I suppose I could use the 60 watt to keep the batteries topped and charged according to my math anyway.

12*40 = 480w, 70% = 336w, 336w/30w = 11.2 hours.

Chances are I won't even run it for more than 150w per night so a 60 watt panel shouldn't have any problems keeping it topped off.

Also any recommendations for a 4 or 8 cell simple bms?

[Mike90250]

Well, you havent' mentioned what your charging source is. If you have a pickup truck, a "monolith" will fit into half the bed.

My rig the Solar Monolith:

Update pictures/information here.


Check this thread too

http://www.solarpaneltalk.com/showthread.php?5343-Newbie-questions-building-emergency-power-setup

[Sunking]

Checking in. Lots of great info thanks all.

Me thinks you are a SPAMMER. You are being watched, so time for you to get paranoid.

[Reidec]

Checking in. Lots of great info thanks all.

I will admit that this one post was spam to get the picture viewing ability.

Fairly new to solar. And I've had interest in LFP bats since I first started researching battery banks. I live in Oahu Hawaii and although we barely have any power problems or any reason to keep a battery bank, we pay $0.25-$0.33 a KwH. Now if you consider an LFP at around it's minimal charge cycle of 2000. Due to our high cost of KwH the batteries would be about the same cost as buying from the grid (given you're not coughing up huge amounts of cash for a bms). Further if I can extend the batteries life by keeping it within the 28% range, the batteries should be able to pay for themselves and then some.

Of course the above is all hypothetical. Point being this post has been the most educational read compared to hopping around google hours upon hours. So I apologize if I spammed my first post but I wanted to see the PICTURES >.<.

My current project I'm working on is a 12v 40Ah solar generator. Very tiny and really just something I'll probably take to picnics to run a small bose 30w sound system or my computer's companion system. I'm just having a ton of problems with the bms portion. I was looking at AU's Ev-power bms as a cheap option but T1's CellLogger 8 looks like a great alternative too. Having to maintain the batteries could be a great learning experience.

If anyone has any other suggestions I'd be happy to hear them. But I assure you I have no intention of getting a high post count. Are you an admin?

T1 Terry on the Junsi CellLogger 8, question is how often would I have to check on the log and adjust. I'm also assuming the adjustment would be made from the controller of course. And would you recommend a controller?

[buchhla]

This is all great info. I am thinking of doing a very similar install to Steve on my boat which is currently in Auckland, though I will only have about half the solar capacity...

[markfoy]

Hi all,
Just to appreciate steve and others. I am learning a lot on this thread

[Sunking]

Lithium Polymer is what the model aircraft batteries are made of,

For model aircraft energy density is the most important factor in such devices because of the weight issue.

For solar, energy density is not important, price per Watt Hour and safety are the most important factors. For that reason LFP is the best choice as it is the safest of the lithium chemistry and the least expensive as prices have dropped to around $0.50/wh for chi-com units.

[Northernflyer]

NMC Batteries

I have another link from battery university on the different lithium batteries and the nmc ones are grouped with the iron phosphate ones for safety. I am still researching but they appear to be one of the better types to use. http://batteryuniversity.com/learn/a...er_lithium_ion

Steve

[T1 Terry]

Thanks for the link Steve. after reading through heaps of spin I found this bit

The Technology

Corvus utilizes advanced lithium ion polymer cells in multi-cell module configurations. These configurations are monitored by a proprietary battery management system to control charge, discharge and monitor all aspects of the module, pack and array.

Lithium Polymer is what the model aircraft batteries are made of, they have special bags for them when recharging to contain the fire if the explode into flames. this is an extremely dangerous form of lithium ion battery and these units must rely on the battery management systems never stuffing up. Anyone who has used a computer knows that microprocessor control can hang or shut down for no real reason, just a glitch or spike or piece of bad information in a packet can cause it.
I sure wouldn't be risking them, the cell type certainly are not in the nieghbourhood of safety compared to lithium iron phosphate, with out an active and fully functioning BMS they are time bombs.

T1 Terry

[Northernflyer]

Lithium nmc

If you go to www.corvus-energy.com they have a good amount of info on these batteries. They are in the same neighborhood for safety as the lithium iron phosphate and seem to be better in all regards such as having a much higher cycle life and a 99% efficiency. I would imagine they are quite expensive.

Steve

[T1 Terry]

I am working on a 6. 5 kw system and are considering lithium nmc or iron phosphate batteries. I am currently doing research and have found Corvus energy that offers these for actual solar systems. I am waiting for more info and pricing from the manufacturer. Will get back when I hear more.

Do you have any info/specs on the lithium NMC cells? What is their stability like? The LiFeP04 chemistry is quite stable, the newer lithium sulphur batteries are showing good stability but life cycles are a bit of an issue. The stability of the other chemistries at each end of the charge cycle isn't real good so it will be interesting to see reports about the lithium NMC construction.

T1 Terry

[Northernflyer]

Very interested in lithium battery setup for a new 6.5kw system

I am working on a 6. 5 kw system and are considering lithium nmc or iron phosphate batteries. I am currently doing research and have found Corvus energy that offers these for actual solar systems. I am waiting for more info and pricing from the manufacturer. Will get back when I hear more.

[T1 Terry]

Hi Steve,
The cells really are full at 4.45v, well, 3.40v actually but the 0.05v over voltage is required to charge and 0.05v under terminal voltage is required to discharge.
Here is a charging graph that shows just how fast the voltage climb is once they are full at 3.45v and how little energy is there at any higher voltage. If you are reaching 3.5v on every cell at trickle charging rates the battery bank is 100% full.
The boost charge voltage was raised to 15v for a nom 12v, sorry but I don't have the amps graph to go with it, it's off powering the ether or something because buggered if I can find it.

T1 Terry
EDT: Here is another graph showing the charging curve.

[T1 Terry]

Hi Steve,
The cells really are full at 4.45v, well, 3.40v actually but the 0.05v over voltage is required to charge and 0.05v under terminal voltage is required to discharge.
Here is a charging graph that shows just how fast the voltage climb is once they are full at 3.45v and how little energy is there at any higher voltage. If you are reaching 3.5v on every cell at trickle charging rates the battery bank is 100% full.
The boost charge voltage was raised to 15v for a nom 12v, sorry but I don't have the amps graph to go with it, it's off powering the ether or something because buggered if I can find it.

T1 Terry