LiPo4 battery selection

mcgivor · March 2018

Recently I met someone who wants to install a solar system to augment the unreliable grid which frequently is under voltage as well as being subject to frequent blackouts. He is sold on LiPo4 despite my suggestion of using flooded LA, I've offered to help but my experience with LiPo4 is, less than limited. Having read threads of others using these batteries/cells it would appear that prysmatic are the way to go, rather than the so called drop in replacements. Done a fair bit of research and have narrowed it down to a few vendors, the price per Ah/cell is $0.75, so a 100Ah cell would be $75 or fractional divisions thereof , the one which stands out is a 24V nominal 240Ah, including a BMS self contained in an aluminum box, any thoughts or suggestions would be helpful. The charging/inverter hardware will most likely be SMA or Schneider due local availability, the capacity will be carefully calculated according to loads, which I'm reasonably well versed, there are so many options regarding cells and capacity, however the primary focus is the inclusion of a BMS, which makes sense, yes/no? This is a link to a possible vendor, I'm in Thailand so logically its reasonable to purchase semi locally for shipping considerations.
https://www.alibaba.com/product-detail/direct-manufacturer-24V-240Ah-deep-cycle_60703345450.html?spm=a2700.7724838.2017115.189.75021834gGbsEg

mike95490 · March 2018

As long as you place the battery in an isolated area where it is unlikely to allow it's fire to spread into house or nearby land, you are pretty much on your own. The quality of BMS varys greatly, and the interaction between charging source and BMS and Load and BMS is currently poor.

Dave Angelini · March 2018

I would want the system to at a minimum communicate Soc, temperature and the other vitals. The inverter needs to be picked to make sure it can't overcurrent the battery. The charge source needs to be matched also.
It is an advanced project that I would not use for a client if there was something pre-made. As Mike said alot of quality issues!

There are excellent choices but it will cost you. I do not see it getting much better in the near term. An example below that I use.
Discover by AES is a direct replacement with xanbus in a 6.5KWH. They are around a thousand dollars per KWH which is typical for LFP
They will take the surge from an XW without damage as the guys who built it worked for Schneider. They are building an interface for Outback at this time. The model below is available in 24V also.

Image: https://us.v-cdn.net/6024911/uploads/editor/dc/yfa4dh70pzjb.png

mcgivor · April 2018

Thanks Mike, points duly noted, its is impossible to know the quality of the BMS without actually testing over a period of time, which would require carefully monitoring all parameters, from limited feedback of others, it would appear there are significantly more components which logically means increased potential for failure, especially on a home brew system. As this is not something I'll actually be constantly monitoring perhaps it's better to go with an integrated system as Dave suggests, which was my initial suggestion, the Axitec/SMA system (pdf attached ) was where I started the price of the battery is ~ $680 per Kw. local and in stock. The attraction to the linked batteries was because all things considered, in terms of capacity vs depth of discharge, it actually works out ~25% less expensive or $130 per Kw than lead acid, shipping costs not included.

LiPo4 battery selection

Comments

Categories