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Mecer LiFePO4 Lithium Ion Batteries: Any experience


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I took a chance and bought a 200Ah one. The Wh number on the comx site is wrong  when you do the math and you can see that someone edited a 180Ah manual to indicate 200Ah - which makes it seem ve

I've been running an old Cyberpower CPS3500PRO since 2014 (2450w, 24vdc). As you can imagine the original Pb batteries are now very tired. They can barely power the TV and a CFL bulb for 90min. I was

Haha thanks for your response. I hope they'll give you a super long service life. I'll use mine as a power backup until I can connect PV input.  @Tim003 I'm sure your earlier question has been pa

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On 2020/03/13 at 11:34 AM, Corné said:

Good day everyone

I saw these today... Anyone experience with them?

 

On 2020/03/13 at 11:57 AM, P1000 said:

I took a chance and bought a 200Ah one.

The Wh number on the comx site is wrong  when you do the math and you can see that someone edited a 180Ah manual to indicate 200Ah - which makes it seem very dodgy - BUT the included manual that I received have numbers that make sense. (it seems that there are 180Ah and 200Ah units. 180Ah was out of stock with mustek/mecer when I enquired)

Overall outer condition seems fine (the battery shell is plastic, but no obvious dents/cracks/scratches - shell actually looks 100% - no idea what the inside looks like and will not take to opening it up...yet).

battery terminals had no sign of use/tool marks etc.

Specs indicate it weighs "approx. 23Kg" - mine weighs 23.4Kg (google suggest the specific energy of LiFePO4 to be 90-120Wh/Kg. So while not knowing the exact weight of the cells, the numbers should get you at least past 2000Wh (160Ah for 12.8V nominal)  at the lower spectrum ...I guess it could contain only 4 cells and some lead bars...)

My cheap multimeter showed a voltage of 13.19V  before hooking it up for the first time (probably fairly meaningless for a lithium, but at least it did not arrive @ 10V) 

I charged it with a Multiplus inverter/charger @ 35A (the manual indicates standard charge as 15A and maximum as 100A) - I was keen to have it charged as I knew we were in for load shedding later the day. It took close to exactly 3 hours before indicating "absorption". Multiplus held absorption for another 1 hour (current tappering off). By my math (which is worse than my spelling) using info from my VRM log, by the time absorption was reached the battery "accepted" about 105Ah and absorption probably added another 15Ah. As far as I know lithium batteries are shipped at about 50% charge. So assuming the shipping charge state and the known charge cycle the math would suggest that it probably is in the 200Ah range.

While charging nothing felt warm (my hand being the closest to a scientific instrument for temp testing).

When load shedding takes a break I  might see if I can get a more definitive answer on the capacity with a sustained fixed load.

The battery has been used this past week and seemed to happily power the very modest average 200W load for 2 hours, then charge @ 15A and be ready at least an hour before the next load shedding session commenced, and repeated this cycle another 2 times per day for 4 days in a row. (I lowered the charge rate to 15A to "baby" the battery when possible, but if we hit stage 6 load shedding I will up the charge rate again). 

The battery has done momentary (couple of seconds) discharges @ >250A (NOT a typo) and so far nothing has melted/tripped/caught fire. The manual indicates maximum continuous discharge as 100A - no information on pulse current. How well the BMS does what it is supposed to do (or whether it is even there...?)  I do not know  and have no intention to short out the terminals, or charge it to 16V to find out. 

The "manual" is 1 piece of A4 paper, but at least it is double sided, glossy, in colour and not written in the worst dialect of Changelese. Probably the biggest issue is one part of the page indicates a charge voltage of 14.6V, and another 14.1V - I suspect the 14.6V is probably the high cut-off. (I set the voltage at 14.1V)

Whether the battery will give me 1500 cycles (this I assume is to another 80% capacity loss) I do not know.

Should you consider one, or more, of these keep in mind (according to the manual):

  • You  can NOT parallel connect to get 400Ah, but you can series connect to get 24/48 
  • "Bulk"/absorption voltage is 14.1V (float @ 13.6V) for 12V system
  • "Bulk"/absorption voltage is 28.2V (float @ 27.2) for 24V system
  • "Bulk"/absorption voltage is 56.4V (float @ 54.4) for 48V system

 

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Also saw the " cannot parallel"  part - which seems very strange to me? Assuming each one has it's own BMS, not sure why parallel of 8x (4x series) of these are not possible? There is no intelligence between them, like many  lithium " gel replacement"  options, no can bus, but don't see how anything will prevent it to be connected that way? Will be glad if some clever person explains :) 

As long as your cable lengths from the positive/negative side of each string matches in length, and of course is thick enough to allow 400Ah (19.2kW! - not many small inverters allow that kind of current anyway) - you should be fine?

They look very similar to another battery sold on some sites a month ago - and I know of a few field installs where they seem to work very well. The other ones were listed as 180 as well - the new ones also 200 - Attached a picture for those interested :) You can see the 4S3P packing. (4x Serial 3 Parallel) 

image.png.f426340c7a8782cc6c3d62382be22985.png

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Open it up! :) Lets see.... :)

What is amazing is working out the R/kW  = under R3000 /kW - if you can parallel - that's  under R50K  for over 18kWh backup - which means you will cycle them 1x every few days only - enough for years... 

Edited by Igubu
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:) you’d be surprised what goes on inside many “fancy” shells.. I look at it this way : less than half the price vs  brandnames, 2-3Y warranty, and in 3 years who knows what we’ll use. In 3Y youd probably still have 60-80% left over... 

People were very happy with 4-12 big lead batteries - a few added an expensive battery monitor/balancer, most probably didn’t.  This is proven tech now, and the perfect replacement for those old batteries, they even work fine with all the old inverters... and you do have a BMS inside that offers protection.

of course it’s not the 10Y warranty, or fancy CAN bus monitoring... but it’s a LOT better than old lead...and per kW also cheaper in fact! 
 

So for  somebody on a tight budget- perfect way to save a big part of the costs, or rather build the correct size system now ito panels, inverters, but just enough storage for loadshedding..

 

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On 2020/03/16 at 7:42 PM, Igubu said:

Also saw the " cannot parallel"  part - which seems very strange to me? Assuming each one has it's own BMS, not sure why parallel of 8x (4x series) of these are not possible? There is no intelligence between them, like many  lithium " gel replacement"  options, no can bus, but don't see how anything will prevent it to be connected that way? Will be glad if some clever person explains

I suspect 2 options.

1) they manufacturer/repacker might mean you can, but should not since it could lead to a shorter total battery life (unhappy customer)

2) you can, but it will do something like damage the BMS since it is not designed to make provision for this (unhappy and/or damaged customer)

and maybe a potential 3rd

3) "you can but we do not want to get sued when someone wants to charge their new battery bank @ 400A and turn their 25mm2 welding cable fastened with a lose fitting coroded washer to the battery terminals into what is initially the worlds biggest lightbulb fillament.." (unhappy relatives of very damaged customer)

From my reading of the interweb it should boil down to a combination of 1 and/or 2 due to issues with cell balancing - which is already tricky with brand new cells (individual cell internal resistance being a major factor).  With these repackaged batteries the individual cells probably already have more variance between them than would be ideal. In this case the BMS may play the role of conductor (like the orchestra kind, not a train or wire connected to a voltage source) and make sure the cells inside the individual case stay relatively balanced - BUT it has no way to communicate with the next door neighbour to syncronise their activities - which leads to individual cells in each battery becoming more unballanced and/or one battery being way out of balance with it's neighbour.

The BMS may  also rather just be bit of a club bouncer (just protects against over discharge etc.) and when parallel connected the variance in charge current is outside the design paramenters and just fries the BMS.

For interest, the Blue Nova LiFePO4  "drop-in replacements" indicate that you can series connect them - BUT each one has a number on and you should only connect batteries in the same number series (114-1, 114-3 should be okay, but 114-1 and 116-3 not). Info on the battery also states "if want to parallel connect, contact supplier for advice".

Freedom Won LiFEPO4  "drop-in replacement" info I have indicate parallel is okay if you do things like make sure the cable lenghts are LONGER than a certain minimum to reduce heat transfer, and charge currect must be set as if for a SINGLE battery (but parallel conection is not covered by the warranty if you do). Series connection MUST have a balancer added between each 2 batteries (and also not covered by warranty).

These guys (https://www.aliexpress.com/i/33028232599.html ) for instance again state that you can series connect but only up to a certain voltage - or the BMS will go kaput.

So the "CAN'T" parallel on the mecer is maybe not that strange.

On 2020/03/16 at 7:42 PM, Igubu said:

As long as your cable lengths from the positive/negative side of each string matches in length, and of course is thick enough to allow 400Ah (19.2kW! - not many small inverters allow that kind of current anyway) - you should be fine?

Even a 200W inverter can run of a 400Ah battery but I think putting 400A DC through almost any inverter will get interesting regardless of the cable thickness

On 2020/03/16 at 7:47 PM, Igubu said:

What is amazing is working out the R/kW 

Definitely think the R/kWh value is good - but obviously with the gamble of whether you "won the lottery"  with very closely matched cells, or got one wonky cell that slowly drags the entire battery down. The "out of pocket" amount was my deciding factor for the standby use I intend (not planning on cycling it every day, and will not try and murder it with high charge/discharge current unless called for)

On 2020/03/17 at 4:24 PM, Crankshaft said:

I was hoping that there were 4 proper LiFe cells inside the case.

Please correct me if I'm wrong.  Perhaps that is what LiFe cells look like inside there casings.

I would feel better if these batteries hand some of those nice yellow Winston (sinopoly?)  cells etc. but i am not sure it matters too much. What I DO want though is the hopefully safer characteristics of LIFePO4 vs Li-Po etc. LIFePO4 do actually come in pouch format but it is still a prismatic cell (for instance https://shop.gwl.eu/LiFePO4-small-cells/Pouch/NPB-LiFePO4-Power-3-2V-100Ah.html ). Again, I do not know what these Mecer batteries contain (opening it up will be quite a mission - very decently sealed/glued etc on all edges).

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On 2020/05/14 at 10:44 AM, Monian said:

New poster, hi all and specifically introverter

I am interested in the Mecer 200 Ah any follow up comments now that you have had it in use for some time.

apologies for only replying now..

Not much to add really. The battery is used only as a backup power source for Eskom  load shedding (I do not cycle it daily) so it has not seen any additional use in the past month or so.

I did one load test which confirmed the capacity on the unit I received (200Ah)

The battery was charged to 14.1V as per manufacturer spec. and then left without any load for about 12 hours. Then a known load was connected. Ambient temperature was about 20.5 degrees C for the duration of the test. The load consisted of a 230W tungsten security light and one small 4W LED bulb which at 230V gave a current draw of about 20A. The inverter was set to disconnect at 10V.  Load was connected at 07:00 (battery voltage just before load was connected was 13.91V) and the inverter disconnected at about 17:03. Total time therefore just over 10 hours (10hx20A=200Ah). Data from the log also indicates that about 208Ah "left" the battery and when charging at 15A (standard rate) about 215Ah "went in". While discharging the battery voltage remained fairly constant until the last 30 minutes or so when it started falling of the cliff.

200Ah_Discharge_Graph.jpg.bc56a856b992d51c83dc47fd8b57c897.jpg

 

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  • 1 month later...

Hi all. First post.

I purchased one of these batteries to use with a new Ceil pure sine wave inverter. Let's just say there were reservations from some of the suppliers on using these 2 together.

https://thepowerstore.co.za/collections/storage-systems/products/mecer-200a-12v-lithium
http://onlineshop.gcsolar.co.za/product/840v-600-w-ceil-pure-sine-wave-inverter/

https://www.createenergy.co.za/ used to have deep cycle lead acid battery kits with this inverter.

Added a 100amp mega fuse and Victron fuse holder on the positive wire.

We have frequent long power outages in our area due to overloaded infrastructure that hasn't been upgraded to cope with the new housing. Hence the need for a ups to work from home. At a minimum I need to power a fibre box and router and 2 laptops.

I don't have experience with using a lead acid battery with an inverter so this is all new, and it's hard to tell what's out of the ordinary. 

It's unclear whether the inverter display is showing me the charging voltage or the voltage on the battery. I'm guessing the former. 

Voltage across the battery terminals was 13.19v on delivery.

I connected everything up. 
With my trusty multimeter, i noticed the inverter gradually increased charge voltage to 14.2v over a few hours and eventually showed the battery as fully charged. 

At that point, I disconnected the inverter from mains. There is no load on the inverter except it's self powering requirements. Even when the inverter switch is set to off, the LCD display and led light stays on drawing 0.7 micro-amps from the battery. 

The voltage across the battery terminals has slowly dropped to below 13.4v over the past day.

I asked the supplier what voltage the battery should be charged to.
The reply was "Lithium Ion battery is not like lead acid, it is a constant voltage through its life. Should be 13.1V-13.4 and will be steady there until a drop off in voltage to battery low."

Still not sure if these systems are compatible, and it's hard to know the state of charge of the battery from the voltage reading. 



 

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On 2020/07/04 at 9:52 AM, zathras said:

With my trusty multimeter, i noticed the inverter gradually increased charge voltage to 14.2v over a few hours and eventually showed the battery as fully charged. 

At that point, I disconnected the inverter from mains. There is no load on the inverter except it's self powering requirements. Even when the inverter switch is set to off, the LCD display and led light stays on drawing 0.7 micro-amps from the battery. 

The voltage across the battery terminals has slowly dropped to below 13.4v over the past day.

I asked the supplier what voltage the battery should be charged to.
The reply was "Lithium Ion battery is not like lead acid, it is a constant voltage through its life. Should be 13.1V-13.4 and will be steady there until a drop off in voltage to battery low."

Still not sure if these systems are compatible, and it's hard to know the state of charge of the battery from the voltage reading. 

not easy to find detailed info on the mentioned inverter/charger but looks like it charges up to 14.4V and floats at 13.7V. Low cut-off seems to be 10.5V. The numbers are 0.1-0.2V over the spec sheet included with the battery I have. I doubt that this will kill the battery, but likely will shorten the lifespan a bit  - especially if it floats at 13.9V (they indicate a +/- 0.2V on the float voltage).

The BMS should protect the battery from extreme over/under voltage (I have actually not tested whether it does... when I discharged the battery to 10V the inverter switched off  - not the battery... the voltage then slowly crept up again).

Basically all batteries will have the voltage over the terminals come down after the charger is removed and come up after a load is removed. On my battery it seems to settle at about 13.6V after a day or so post charging.

The voltage curve of lithiums tend to be quite flat - in other words the voltage over the terminals will unfortunately tell you close to nothing about how full/empty the battery is. Unless the battery has a more advanced BMS you will need some version of a shunt (like a victron BMV) to have an accurate indication of battery state of charge.

Not sure if this addresses your concerns?

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Thanks for the reply and advice introverter. I realise I have taken a risk by not getting a better inverter\charger like Axpert or Victron where you can set the charging and cutoff voltage. In hindsight, the 1kva 12v Axpert mightCeil inverter manual.pdf have been a smarter option.

Given the low self discharge rate, I'd rather sacrifice some backup capacity and not keep it on float charge to prolong the lifespan of the battery. I also plan to disconnect the load when voltage gets below 11v.

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14 hours ago, zathras said:

I realise I have taken a risk by not getting a better inverter\charger like Axpert or Victron where you can set the charging and cutoff voltage. In hindsight, the 1kva 12v Axpert might have been a smarter option.

Given the low self discharge rate, I'd rather sacrifice some backup capacity and not keep it on float charge to prolong the lifespan of the battery. I also plan to disconnect the load when voltage gets below 11v.

I think that is a sensible approach. If you are happy to manually intervene I do not see a reason to spend 2-3 times what the Ceil likely cost you to get the axpert/multi. By the way, there are only two things I did not like about the axperts when I was shopping around -  the listed no load power consumption is almost double compared to the multiplus and setting the charge current limits you to 10A increments but these are not deal breakers and was not the reason I ended up with a multiplus.

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I've been running two of these in series on a 24V for a week now and I'm very impressed. I have no reason to doubt the 200Ah capacity rating. The construction looks decent and my (also single page) datasheet had the correct 2S voltages of 25.6V / 27,2V and 28.4V (nominal / float and bulk).

I ran a capacity test lasting 19h and these are my results. The total capacity turned out to be 5.35kWh (rated in 2S configuration is: 25.6V nomimal x 200Ah = 5.1kWh). The higher capacity is due to very low C rate of this test.

One thing I did notice is that the battery voltage is greatly impacted by the load power with increases / decreases in the load clearly visible in the graph below. Note, detailed measurements were stopped after 12h, the load was simply kept constant after this until auto shutdown at 22V after 19h.

Total runtime (h) 19
Ave load (kW) 0.232
Ave discharge rate (C) 0.045
Ave inverter power usage (W) 50
Total kW used by load (kWh) 4.4
Total kWh used by inverter (kWh) 0.95
Total kWh produced (kWh) 5.35

 

image.thumb.png.785ce56eafe6f85341a38ae57b15f5db.png

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Hi all, great thread. I am new to this and was wondering if my current inverter (24v model) https://mecer.co.za/ivr-2400lbks-24v-inverter/ would work with 2 of these Mecer 200ah LiFePO4 in series? Currently have 2x 12v 100ah lead acid but has reached the end of their life.

The spec sheets seem to be a match but not know too much about LiFePO4 vs Lead Acid.

If this inverter not sufficient, which one would you suggest?

 

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HI Milkworx, where are you based? CT or JHB? There are a number of newer options in the DIY space these days that offer more up to date BMS, newer prismatic cells (note sure about the latest one - but the early Mecer ones were soft pouch cells) and probably at similar R/kW price - but depends where you are based. 

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Hi all, another newbie here.

I've just seen a slightly different version of this 200ah battery and it looks like the specs are good (to my very green mind with about 10hrs of forum education). I've attached the spec sheet below.

I have a 3kva/2.4kw Axpert clone hybrid inverter that'll be used to power essential loads. 

Would this be a good buy?

 

 

 

 

Vision-Revo-12.8V200Ah-V04.pdf

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Hi,

Is your inverter 24 or 48V?

Just to comment on “if ot’s

good’ - i heard there is about 28 different variants of this battery, in the same case on the market locally  :) so the “Mecer” brand is often used to quote the “what” it is... but many different flavours of it, and unfortunately different quality inside, different BMS and made different- some older cheaper ones are pouch cells, the newer better ones are prismatic inside- much better.

To get back to the inverter question- if it’s 24V, you need 2x of these, makes sense - roughly R15K? If it’s 48V, you need 4x - at which point (price and quality) I would rather look at some other 2nd life options perhaps. I’ve seen some pricing of around R20K for 5kW/48V for 2nd life, and the same price for 3.5kW “brand name” brand new cells (10Y warranty) 

If it’s 24v/2x of these - think it’s a good fit. 200A x24V roughly 5KW of capacity. 
 

B

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2 hours ago, Igubu said:

Is your inverter 24 or 48V?

Hello @Igubuthanks for your response. It's a 24v inverter

2 hours ago, Igubu said:

Just to comment on “if ot’s

good’ - i heard there is about 28 different variants of this battery, in the same case on the market locally  :) so the “Mecer” brand is often used to quote the “what” it is... but many different flavours of it, and unfortunately different quality inside, different BMS and made different- some older cheaper ones are pouch cells, the newer better ones are prismatic inside- much better.

I've also seen the Mecer branded ones and this line was almost always there 👇🏾

"NB: No Parallel charging ability and max 4 in Series"

So that kinda put me off and that's why I got a little excited about this one. The site claims 👇🏾

"The BMS supports a matrix of 4 battery in series – x 4 battery in parallel. – A total of 16 batteries in the matrix"

Not sure if it's not another scam site but here's the link 

Vision 12v lithium 200ah

2 hours ago, Igubu said:

If it’s 24v/2x of these - think it’s a good fit. 200A x24V roughly 5KW of capacity.

Yes, that's what I'm thinking. I've been comparing this with the Giter brand but these cells seem to have a lot more going for them than that option (i.e. 1C vs 0.5C, 200Ah vs 100Ah, price etc.) but I'm no expert that's why I value the opinions of the people on this forum.

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26 minutes ago, JaseZA said:

Thanks @JaseZA for the heads-up

27 minutes ago, JaseZA said:

I'm amazed by the price of these - works out even cheaper than buying raw prismatic cells

That's very true especially if they perform as advertised it'd be a steal. I will compare the specs for these with the prismatic cells at Lithium Batteries SA just to see which of the two is the real deal.

30 minutes ago, JaseZA said:

Would love to see what's inside these newer ones! If it's 4x200ah prismatics I'd buy them, strip out the cells and use my own BMS... 10kwh for R25k!

I just checked the documentation and it looks like they're using 100Ah cells in a 4S2P arrangement

 

SmartSelect_20210301-085301_Adobe Acrobat.jpg

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