Battery Test Centre

[Bala]

I have not seen this posted before and it looks to be ok.

Test centre running many brands of batteries, they cycle them 3 times a day.

You can get real time battery data and reports about failures etc etc.

If you go to batteries and select one you will then be able to see them all at once.

http://batterytestcentre.com.au/

[Ampster]

It looks like they mostly tested preconfigured packs not individual cells. I will have to read more.

[Bala]

Yes looks like testing what I suppose you would call retail batteries.

It is of interest to me as I had Flooded for 12 years and have just installed a set of BAE Sealed batteries.

My next step will be to get a complete new system installed by a company and I would think by then there should be some good data on lithium brands and the back up from the installers of those brands.

[SunEagle]

It would be interesting to see a cost comparison for each of the battery systems. But that might be hard due to the equipment and installation cost would vary greatly across the US.

[PNjunction]

Interesting site. They bring up issues about LFP that would be easy to gloss over, which we have mentioned here before:

1) LFP is the least-costly lithium battery type to manufacture. Are you paying too much compared to non-lifepo4?

2) Sure enough, LFP is less energy dense than non-lifepo4. That means about 30% larger for the same capacity. That can be accomodated in our application easily enough. Ok.

3) *POWER* density - not really mentioned. LFP, unless specifically manufactured to be "high-rate" are the lowest power-dense cells in the li family. And that's OK for our application. For our use, think over-grown "solar patio light batteries". This power-density is what makes them unsuitable for sustained high-current demands, such as EV's. Oh yes, that has been tried in the past, both commercially and DIY with some success, but for EV and high-current usage, specially constructed LFP is needed. Think Headway cells for the likes of wheelchairs and such. But bog-standard prismatics such as my own GBS cells - big solar patio light cells. But that was ok for my application.

So if you choose to go prismatic, or other types of LFP, we don't need the high-rate cells. More money wasted if you do.

A good example is pricing the typical LFP motorcycle-starting batts, vs conventional low-rate cells like common 32700's out now (big solar patio light batts basically). KNOW your power-density needs, which in our case is low. It would be absolutely NUTS to build a house-bank out of high-rate Headways.

4) Charge algo - I see the site mentions that they only discharge down to 80% DOD. An instant 20% de-rating. And that's fine - because when you go down farther than that into the knee, you have to modify your recharge current to be lower until it comes out of the knee (typically once reaching 3.2v) whereupon you can charge with the normally spec'ed current rating.

Don't believe me? Grab a quality set of low power-dense LFP cells like Westinghouse solar-patio-light cells and a hobby charger. Discharge them to 90-95% DOD. Recharge at .3 - .5C, and watch the cell voltage rise, and STALL as it tries to deal with the inability to deal with fast intercalation (ion-storm). Fortunately, in a house-bank, many of us won't have the ability to hammer our house bank at .3 to .5C so this problem may be minimized. It will always be minimized for very tiny banks / large solar arrays, if you don't discharge past 80% DOD.

Anyway, interesing site, and I'm glad they brought up some issues - but if one isn't aware of how cheap LFP *should be*, we'll be paying through the nose forever until we stop agreeing to pay the prices for the cheapest lithium cells to make, especially the low power-dense versions.

[Bala]

I installed my current system but lithium cost to a certain extent will not the driving factor of my purchase of a new system, it is convenience and support from a dealer.

I have plenty of hobbies and dont want my electricity supply to be a hobby so I want ready to go drop in batteries.

We will be away more in the coming years and as our house is next to a wet tropics rain forest and it attracts rats and grass grows so quickly we need other people to stay and care take.

I need to set up the electricity supply so that people who stay cant hurt my batteries and dont run out of power and if there is a problem they can ring the local dealer who installed it and I dont have to stress if I am away.

I worry that the tech required to control lithium will have problems in our wet tropics environment but in time I will pick a supplier and get them to install a complete system that will be legal and that will also help if we want to sell.

I was just reading about new laws in Australia aimed at battery systems which are similar to what is talked about on the forum in the US. 48V batteries are still ok for handyman but using MPPT controllers often means high solar voltage which means you need to be an electrician, so the game is changing here now.