LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[s/v Holiday]

Originally Posted by Surf City

CJ,

I have been looking for a source in the US, I have seen CALB and HiPower for sale on couple EV sites along with the hardware to tie terminals together. Just have not pulled the trigger yet. We are leaving in June and need to get my order together. Would like to get hands on Sinopoly batteries but have not located a source for them.

How many amp hours are you looking into?

Wil

Hi Will,

I am thinking 800ah to 1040ah. Probably overkill but I want a few days of reserve power. Any specific reason you like the Sinopoly over the others?

CJ

[Surf City]

CJ

My understanding is that the new batteries that are coming out are a 1/3 smaller in size and weight for the same amp hour rating. But I am not sure if they will be available in the next month, so looking at other brands.

What do you believe your daily amp hours usage will be? We have 705 watts of solar, I'm estimating that we as a family of four will use 200-250 per day. Solar will replenish that daily, but on a cloudy day we will rely on the batteries. We have switched over to led bulbs. Our biggest use will be refrig and freezer around 120/day, maybe less. If we have 600 ah in batteries, then theoretically I have 480 usable ah to be used or roughly two days worth. Solar still gives me some energy on a cloudy day. Our back up will be the generator which will run to make water and anything else needed.

Have you decided your battery setup in regards to ah battery size -100 or 200 ah cells? Manufacture of battery?

Wil

s/v Full Monty | Keep up with us as we sail the world and its many remote places.

[s/v Holiday]

Originally Posted by Surf City

CJ

My understanding is that the new batteries that are coming out are a 1/3 smaller in size and weight for the same amp hour rating. But I am not sure if they will be available in the next month, so looking at other brands.

What do you believe your daily amp hours usage will be? We have 705 watts of solar, I'm estimating that we as a family of four will use 200-250 per day. Solar will replenish that daily, but on a cloudy day we will rely on the batteries. We have switched over to led bulbs. Our biggest use will be refrig and freezer around 120/day, maybe less. If we have 600 ah in batteries, then theoretically I have 480 usable ah to be used or roughly two days worth. Solar still gives me some energy on a cloudy day. Our back up will be the generator which will run to make water and anything else needed.

Have you decided your battery setup in regards to ah battery size -100 or 200 ah cells? Manufacture of battery?

Wil

s/v Full Monty | Keep up with us as we sail the world and its many remote places.

Hi Will,

I figure our daily use will be about 300ah. I am trying to go without a generator so I figure extra ah is the way to go as they still will not weigh as much as my current lead acid ones.

We are setting the boat up for a trip through the south pacific so we will be at anchor most of the time.

I am looking at buying from Winston battery in china. Just would like to hear from someone who has bought from them. It is a bit unnerving sending that much money to china with now real guarantees.

CJ

[Surf City]

CJ

Winston and Sinopoly are very similar. They both started from Thundersky or their technology did. I believe that they are in a legal disput with each other.

Are you going to use a BMS with your batteries? There is a little MiniBMS but I am not sure if you use it on each cell or battery pack(12volt). More research required.


Wil

[sytaniwha]

CJ,

I bought directly off CALB in China, and they air shipped to me. We are currently in Malaysia.

I initially also worried about sending money, but that was groundless.

CALB were very prompt and professional, and replied quickly to any questions that I had. Now over 1 year later they still reply to any questions I have.

I have no experience with Winston or Sinoply.

I hope this helps.

Paul.

[Surf City]

Paul,

Was there any difference buy direct for pricing?

Wil

[sytaniwha]

Hi,

I'm not really sure because there aren't any suppliers out here in Malaysia, so it's difficult to compare.

I expect that you could get cheaper prices from a supplier who orders a lot - my 4 cells wasn't exactly a critical order for them.

I got them for US$1.25 per Ahr about 18 months ago (400 Ahr CALB prismatic cells). That included all the connecting links and the braces to hold the battery together. That seemed to be a pretty good price at the time - I have no idea what the prices are now.

To be honest, whether they were $1.20 or $1.25 was less important to me than the support, and CALB were excellent: promptly answering my many questions on charging, and sending me detailed charge/discharge curves at different rates.

I paid in US$, and pre-paid 100% before they shipped (normal for an unknown orderer of a small quantity, but a little scary at the time since the emails were gmail & yahoo rather than CALB domain). They shipped within a few weeks, and were matched for internal resistance and capacity and were consecutive serial numbers from the same batch.

Cheers,
Paul.

[Surf City]

Hi Paul,

Do you like having 400 ah in one battery or would have several smaller ah batteries to build up to 400 ah? It seems simpler to have one battery but on the other side (having all your eggs in one basket) theory. I have looked at the CALB batteries and they are available in the US for about the same price you paid. Are you using a BMS?

Thanks

Wil

[sytaniwha]

Hi Wil,

If you go back through earlier posts you'll see a lot of detailed info on how I'm charging, how I balanced the cells, the equipment I'm using, etc etc; so rather than repeating it here I'll suggest that you look through those. There's also a lot of other significant learnings from other users of LiFePO4 as house banks.

To answer your specific question: no, I don't use a cell based BMS. Again, lots of details are given by various users (including myself) in previous posts on this thread.

Regarding the cell size: I prefer to use fewer & larger cells and keep external interconnects to a minimum. Having worked in the rechargeable battery industry previously, I believe that larger cells have significant advantages through quality control in manufacturing plants and the capability of the manufacturer to better match and pre-condition the internal plates. It does depend a bit on the internal configuration of the cells, but the CALB 400 Ahr cells look to be well made.

Others have different viewpoints on this, and there definitely are some advantages to having small cells in both series and parallel configuration. As with most things, it probably doesn't have a huge impact on reliability either way.

If you are going for a series & parallel configuration, look back through the discussions on this thread regarding the physical and electrical layout of the configuration - that's critical with a series & parallel system.

Cheers,
Paul.

[Surf City]

Thanks Paul,

I have read thru before but I must have glassed over in some of the sections. I will review them again and see if I can retain the info. Some items stick in my brain better than others. I have several layouts for serial and parallel layouts but most are for 3v strings making 12v in 4x4 parallel layouts.

Back to #1

Wil

[sytaniwha]

It can get a bit tiring looking through the old posts - but I think that's probably better than re-posting the same idea again, as that just makes the thread even longer for future readers.

Back on page 18 there's quite a bit of discussion, and some photos, of series/parallel battery connections, and I posted an image with a few options shown diagramatically.

Hope this helps.

Cheers,
Paul.

[deckofficer]

Originally Posted by sytaniwha

Hi,

I'm not really sure because there aren't any suppliers out here in Malaysia, so it's difficult to compare.

I expect that you could get cheaper prices from a supplier who orders a lot - my 4 cells wasn't exactly a critical order for them.

I got them for US$1.25 per Ahr about 18 months ago (400 Ahr CALB prismatic cells). That included all the connecting links and the braces to hold the battery together. That seemed to be a pretty good price at the time - I have no idea what the prices are now.

To be honest, whether they were $1.20 or $1.25 was less important to me than the support, and CALB were excellent: promptly answering my many questions on charging, and sending me detailed charge/discharge curves at different rates.

I paid in US$, and pre-paid 100% before they shipped (normal for an unknown orderer of a small quantity, but a little scary at the time since the emails were gmail & yahoo rather than CALB domain). They shipped within a few weeks, and were matched for internal resistance and capacity and were consecutive serial numbers from the same batch.

Cheers,
Paul.

So that is $1.25 per amp/hr @ 3.2 volts, meaning a 400 amp/hr 12 volt bank shipped at $2000.00? That matches my best quote.

[sytaniwha]

Yes, correct at US$2,000 for 4 * 400 Ahr CALB cells, with interconnects etc.

Paul.

[deckofficer]

For the folks that their toes have just curled upon learning the price, now that their down to this price, they are on par (or a bit lower) than AGMs for their increased cycle life, not to mention not having to haul out old batteries for many years.

[sytaniwha]

Sorry, extra info on the pricing. At the time (towards the end of 2010), some people on US EV sites were suggesting that they had quotes in the US$1.21 range for cells, but it was really hard for me to figure out which cells, and then what shipping and landing costs would be. That's why I was happy with the price I got.

I think people are a little reticent to post pricing, but it's very useful to people considering the technology. I see now that US based resellers who used to post pricing on the web now ask you to contact them. I'm not sure what that means exactly regarding supply and/or demand.

I also think individuals are reluctant to post specific pricing because sites can get pretty ugly, and no-one wants to be told that they got ripped off, etc.

From my perspective, I think I got a competitive price, and more importantly I got great customer service.

Cheers,
Paul.