Igubu

Glad you have a workable “workaround”- at least 10Amps gives you 500W approx- so should be able to fill up the sunsynk batt in 8 hours or so.. if you can get 20Amps min your golden! yes it’s incredible that the same issue exists years later. out of interest: the diy comms cable..? Does the inverter not have can bus interface and are you using rs485 or usb? I know the sunsynk batt CAN cable is just a normal flylead- unsure about the inverter, not up to date with them. * found a link! Think rs485 might work as well with sunsynk batt - unsure. You’d need at least 3x 545 panels to work nicely https://www.mecerpc.co.za/pdf_downloads/20/206710_PDF1.pdf

If it’s for a cottage- probably more remote- so self built batteries not the best idea- as they tend to be slightly cheaper, but have a lot more returns/issues. The builders sort you out eventually- but if you don’t want the hassles, pay a little but more for something proven. Victron good reliable kit for sure- think exsolar in Somerset West are one of the main guys. They also sell FreedomWon batteries- more expensive- but built to last- so a lot of over engineering- again might be the right choice for a cottage if it’s remote.

BU is old school yes… don’t think they are updated with latest developments in new batteries… Lithium absolutely wants to be charged to 100%- lifepo4 anyways… the older ncm based ones used in EV’s preferred the 20%-80% band, but more so for the “fast charge” portion… they are very different to lifepo4 ‘s used for solar storage… It proves the point there is a lot of miss-information around, lots of outdated articles etc, and a lot of confusion with acronyms etc. Most people just think “Lithium” of “LFP” is enough to indicate what it is- but it’s not unfortunately. Biggest impact on your Mercer's is rate of discharge/charging and temperature. The inherent chemistry will give you the cycles it can - but remember they are already used/2nd life and even “cycle count” is calculated differently between manufacturers…

Apologies, based on you currently running 2x 100a’s thought you’d replace with 2x. Purely based on AH, yes 1x could do- but remember there is a big difference in how lead acid and lithium’s “percentage full” (SOC- state of charge- lets learn the lingo ) are measured. Your trolley inverter only understands Volts- and the decharge curves are completely different. In layman’s terms- you will get less actual capacity with the Lithium compared to the LA with the same settings- especially under load.. glad to explain in more detail if you want to- but it becomes a long post then

Not anti any Brand, there are more than 20 different rebranded versions of this same battery on the market in SA… I’m offering advise based on experience…you are lucky to get 2 years, but have you actually ever load and capacity tested them? New and now? I’ve said this a few times- people that don’t understand the technology just look at one thing: Price. They think a mecer/any brand of these cheap lithium’s @ Rx thus Rx per kW are way cheaper than another brand based on selling price only…. Surprise surprise it’s untrue. There is a very small niche market where these could be used, ie LA replacement- think gate motors, alarm backup etc, where very low current is required, and cycling doesn’t happen - so NOT a solar system in SA where we load-shed constantly. There are many Technical reasons- you can speak to installers who’s in the business for many years- or educate yourself a bit- simple few google searches to explain the basics of batteries, chemistries, BMS and comms control systems etc. The correct battery will give you 6000+ cycles and retain 70-80% after that- thats many years… vs your cheap lithium that will probably not even give you 100% capacity on day 1 (they use 2nd life cells that are already years old) and degrade to 30% in under 3 years… So purely advice to not waste money in the short term…

I see hubble has a s-200 now… also prismatic lifepo4, and online around R12K. Would be much better option than 2x mecers. I know you said cashflow is an issue, but you are wasting a lot of money long term sitting with old 12V inverters and batteries. Also lose at least 30% of usable capacity because of not using CAN interface between the battery and inverter. a hybrid or even off grid 48V inverter with a 48V battery will be much better in the long run, and you could even add 3 or so panels (which you can find 2nd hand) and at least get some money back… not sure if thats an option. As an example you could buy a proper Dyness 5.5kW for around R26K, and a small 3kW kodak around R10k or so (i’d recommend a sunsynk hybrid of course but it’s a lot more) Add a few panels and you could run most things with a bit of management….

Are you happy with the trolley as such? Also are you CT based or elsewhere? not sure if the s-200 has also moved to lifepo4 like the new am’s - if not i’d look for something that is… I could send you to somebody that manufactures these- but he’s CT based- might save you some cash. also unsure if the mecer’s have perhaps changed to prismatic lifepo4 cells, maybe try and find out. I’d wager all manufacturers are moving to it as the old pouch cells all fail after around 3 years… Another option perhaps- look for somebody who has some 2nd hand ones and buy a couple on the cheap (around R1500 each)- stick 2x or even 4x together and at your modest 600W load they might be good for another few years.

Update perhaps? Have a similar issue at a friends house… change wiring, RCD’s etc, neutral/earth bonds with relay all perfect, only thing not changed/removed is the CT… but that is needed to block export, worth a test I suppose? Still fine your side? I’m assuming no CT installed?

If you scroll to page 9 - the “workaround” from HermanD was given: ”Hi Smirresa, Yes, setting 11 set to 2A and setting 16 set to CSO. In CSO the inverter will only charge from utility in bypass mode when there no solar. If you are in bypass mode, but there is solar (cloudy day with batteries low), then the AC charge will not occur. If you are running from batteries and no solar (at night time) then the AC charge will not occur. AC charging will only work when you are in bypass mode and no solar.” Also on the same page 2 posts of the pcb and some arabic text (use google translate” and pictures of a possible fix- but nobody tried and replied that it worked ever- so would try HermanD’s workaround first.

There might a few reasons - these axpert inverters really weren’t great, but if you read the 4Y + history of error 8 and ALL the rebrands using voltronic powers’ pcb, they all had the same issue, utility charging has a design flaw and the bus V shoots up to 600+. There is a long forum post history about it, many things were blamed- seemed to happen when it was raining, so panels and joins were mentioned, but coincidentally was because of rain batteries ran low and utility charging were used. Some clever engineers explained why, how to physically modify the pcb, or add a “push button bypass” to reset the issue manually- but it all came back to the same old pcb design flaw. When I say all- any of the axpert,rct,mustek,growatt etc rebrands - they all used the same mainboard with that 145V mppt limit… maybe newer models have fixed it. Only workaround that was confirmed by many in the field to help , was limit grid charge to as low as possible- or disable if it’s an option. The logic of grid charging at 2A when raining is flawed for sure- you’ll never get the batteries charged during these multiple loadshed days, but that’s what you were stuck with. I remember a year or so ago somebody sat with the same issue- the best advice- sell the inverter for somebody that uses it for ups mode only, and buy a decent one- small sunsynk 5kW hybrid comes to mind…even the newer versions of this- but if you consider a kodak 5kW for R14K- save up and buy a hybrid sunsynk for 20k- worth it for many many reason, but not tue correct page to explain the differences and advantages of proper bi-directional hybrids vs “off grid” ups style cheapies like axpert/kodak. If you are desperate to fix this- and cannot disable/limit grid charge, scroll through the history of error 8 and, somewhere the post with engineering changes required by somebody in Saudi I think was posted- but this involves opening up, and soldering- some surface mounts, so obviously for somebody that’s comfortable doing that kind of thing..

Hi Stormpie, It’s not a fixable issue, inherent design issue. Only work around is to set grid charge to min, think 2 amp or something, or disable charge from grid in CSO if possible.

All the best - please report back here

Hi Rochelle, Seems it’s been a journey! My first solar system 9 years ago was 2x old axperts and 4x 200ah gels - worked well for a few years - inverters anyways… somewhere in the last 2-3 years axpert changed design, possibly outsourced something to get it made cheaper.. and they started supplying numerous other companies with the same flawed design.. (kodak,mecer,rct,growatt the list goes on….) I’ll give you the correct advise, but not what you probably want to hear. The error 8 will not go away, firmware will not help. Loadshed etc is going to be a thing for many years- nobody wants to struggle. The rest of your components are very good (hubble has CAN as well)- get rid of the cheap axperts- return the one if you can, sell the other one to somebody for a few grand, and buy a proper hybrid inverter. With a little management , maybe not even, a single 8kW sunsynk will make all your problems go away. You will be able to get at least 20% more usable capacity out of your 10kW battery bank because of CAN, and the mppt’s themselves will probably generate 10-20% more power from the same panels - they really are that much more efficient than axperts! Yes the 8kW is around R34k, yes somebody (preferably a master installer - sunsynk has a list of them in SA) will charge you again to install- but probably the same as just changing things back. Simplify things, no more split db boards, EVERYTHING on one inverter via 1 main DB. Dont stress about it- solar is a journey, we all learn as we go, but believe me it’s not worth struggling with Axperts. Happy to explain anything around additional benefits and options around Sunsynks ( Have one myself)- but many others will also recommend them as the only worthwhile option. * just read the old Post from a while back… see I repeated a few things :).. btw your SBU has to be on CSO, but read the old post on what that means. Also forgot to mention your sunsynk has 2x mppt inputs, split into 4x string inputs- so you can use both your pv arrays with one inverter, installer just needs to check string sizing-wiring, which will be different compared to Axperts..

Sure it’s not just no loadshedding last week or so? It’s the discharge/charge from util that triggers it when adding loads.

@TimCam Fantastic to hear somebody doing it the correct way. Bus-Bars should really be part of any install - most installers dont do it - or if they do, completely undersize the copper in width and thickness. Always find it amazing that it takes 1 internet search to see what size wiring for size of battery bank is needed - say 50mm for 200Amps - yet people insists on using 25mm - "because it works". Same applies to fuses and bank sizes...how many "standard" 160A DC fuses are used on battery banks of 200,400,600 Amps!? The exact same applies to Bus Bars (Buzzbars? there are so many different spellings!) - a small 10mm wide by 2mm thick is NOT sufficient.... And that age old argument - " A proper bar is another R1000 - and thick battery cables are "expensive" - another R500 more!" .. after you have just spend R150-R250k on something that needs to last for years. When an electrician (a good one anyways) tells you you need an xyz breaker in your DB and it costs R1000 - nobody cares.. but when people install PV systems they choose the R150 cheap breaker... Maybe take a picture of it if and share for others to see what we are talking about?

The issue has been described a few times- you have to drop utility charging to minimum (2A?) and the problem should go away. It's an inherent design problem, unless you solder resistors on, changing Util charging to 2A is the only workaround that helps. It has nothing to do with panels, grounding etc. It does make it almost unusable - as 2A charging is very low - but at least better than it tripping. to

thank you for commenting. Can you post a picture of it after already done? Some other engineering solutions were also offered, but my opinion is it’s a design issue from factory, so Axpert/Kodak/Growatt etc who all use the mainboard should recall and fix it themselves while these units are still new and under warranty.

Here some basic settings below - you can reply with your values here - again - you don't mention solar, so a lot of these depends on solar panels, charging from them etc.. Here from the manual for the 48V Axpert-MKSII_5KVA - Manual V1.2 -but you might have a different model. Error 08 can also be internal, so incorrect installation.. but lets check model of inverter and batteries first and then your settings. 01 - SBU/Uti - Utility First 02 - 10A 03 - APL 04 - SdS 05 - AGM/USE? 06 - Lfr 07 - trd 08 - 230v 09 - 50Hz 11 - 2A 12 - these will only have values if setting 01 = SBU or SOL - if set to SBU - what are your settings here? 13 - Your values? 16 - Your values 18 - bOn 19 - ESP 20 - LON 22 - AON 23 - bYd 25 - FEN 26 - Your Values 27 - Your Values 29 - Your Values 31 - SbE 32 - Depends on setting 05 - USE or ont 33 - EdS 34 - 37 - should be blank as 33 must be disabled. 38 - Neutral bonding depends how it's installed by your installer, and physically bonding the correct wires 39 - NA (33 disabled)

Hi Rochelle, 2 Possible scenarios I think - the first is the " usual error 08" .. comments about that first. Error 8 are notorious with all " Axpert" mainboards..these include, Axpert, Kodac, RCT, Growatt etc etc..they all use the same mainboard. The only thing that helped (proven by a lot of users) was to set utility charge very low - Think it's setting 11 - set it to 2A (Amps). This means it will only grid charge at a low value- if you can live without grid charging, set it to 0A if possible. From " HermanD"'s solution earlier: " Yes, setting 11 set to 2A and setting 16 set to CSO. In CSO the inverter will only charge from utility in bypass mode when there no solar. If you are in bypass mode, but there is solar (cloudy day with batteries low), then the AC charge will not occur. If you are running from batteries and no solar (at night time) then the AC charge will not occur. AC charging will only work when you are in bypass mode and no solar" . Second scenario is the usual troubleshooting steps: What are you settings, are there any errors logged? You mention plugs only - but " plugs only" can definitely trip something. The inverter and Hubble have max charge/discharge current settings - what are yours set at? Another thought perhaps - are the Hubbles the models with CAN interface, as well as the Axpert - or are they configured without comms, and just set using "AGM/Lead" Volt values? Assuming the installer here is professional and knows his stuff? Getting a better hybrid inverter like a Sunsynk "could" solve some of your issues, but it's not necessary unless all steps to resolve has been tried. Only valid reason would be if you require a larger inverter to carry all the loads for example. There are many other reasons for it, but in your case, not required right now to just make your system work. Interesting that you now have 2x inverters, and 2x separate battery banks - hopefully these are not connected in any way on the same DB. Connecting batteries in series will increase Voltage - so if you had 2x 12V batteries - in series they will be 24V. Not sure how increasing V will solve anything if the installer is already saying the "V is too high" ..The V has to match what your inverter is - so perhaps lets start there. To assist a bit here, lets get the basics first: Which Model of Axpert do you have? There should be something on a sticker to show the exact model. Which Model lithium hubbles do you have and how many of them? Are they connected in Parallel (so double amp hours, but same V - assuming 12V or 48V) Once we know that, we can pull the axpert manual up and check compare your settings.. Last thought - you mention lawnmower for example trips it - that sounds to me like too much load on the inverter/battery/combination of both. You don't mention solar panels - assuming none? The reason it works in municipal mode is you are essentially in bypass - so the inverter wont trip, as it's literally just letting the power flow through from the grid.

Forgot to comment about buying a charger- if you want to a decent lifepo4 charger will set you back at least 1500-2000! And its only 12V, so lots of disconnecting battery terminals every few weeks- which is downtime- and dangerous! 100A is deadly. A cheap charger will damage your batteries quickly. You’d be throwing money at a problem- better to spend it on the correct batteries and inverter.

Hi, Basics first please ignore if this seems trivial, but you newer know… as always… a slightly longer explanation- I like to share :) This might be easy- cables, or not easy- new kit… Battery cable lengths for interconnects need to be the same length and thickness, and your end cables (+ batt1 and- batt2) to the dc fuse also the same, as well as your fuse to inverter cables. Also at least 35mm, ideally 50mm for 200A. Can you confirm? Also perhaps how they are physically connected, assuming good crimps etc- maybe a photo! also which inverter and what settings? Might have mentioned earlier, sorry but I’m not following the thread closely.. If all of this checks out- then unfortunately another example of non intelligent bms limitation. I’ll explain: There is always a difference between say first cell closest to charge terminal (can’t remember if it’s + or - side!) and the last cell furthest away. Just how electrons flow… Thats part of the function of the bms, to monitor individual cells within the battery and balance them per cell. Balance really means controlling charge to each cell individually. A “fancy” bms that supports series properly talks between all the bms’es and that way balances all of them to be the same. (Small diff if 100mV or so) It also talks to the inverter via CAN- and actually controls all the charging- so while cells are settling it might instruct a bit more charge here and there- eventually balancing perfect between all cells. Using a lithium battery without this means it’s treated as normal lead acid battery, so basically the inverter charges it bulk to get it to “full” say 14.6V. Lithium cells also settle- similar in a way to old lead acids- so they are “overcharged” to say 3.6V per cell and they then settle to 3.4V as an example- differs per type of cells, but it’s controlled very finely per cell. With your setup the inverter just see’s a big 24V battery, and it controls and charges till whatever setting you set- say 24V (just a value to illustrate 100% full) and lets assume you have 4x cells per battery- so if they were perfectly balanced each cell V would eventually be 24/8 = 3V. Unfortunately you might very well have a couple at 3.2V, some even at 2.9V - many reasons for this - but the total is 24V- so inverter stops charging. Repeat this a few times = unbalanced! Another part of a bms is to report individual cell health- sometimes a cell is always under- showing a fault, but you wont know that with the basic bms. To get rid of this problem you need 2 things: A smart BMS with CAN interface, and an Inverter with CAN. No amount of external “balancing” will help. Was discussed earlier- there are diy battery builders (I know of somebody in WCape) that will build you a new battery- using your cells, but then adding a new bms with CAN etc - but it’s really expensive, and of course your inverter needs to support CAN to get the most benefit, withou that you’ll get the balancing sorted at least (it will be an eigth cell single 24V battery, not 2x 12V in series anymore) but still the other negatives of at least 30% unusable capacity. much better to sell them as individual 12V’s, get rid of the inverter if it’s a non CAN, buy a newly made up 24V battery and inverter that supports CAN.. Hope it helps!

Amazing definitely then an “advanced”’user if you are looking for a can compatible bms- seplos in china has a 16s 100A and 200A unit… but unsure about single imports- last I heard you were looking at R4500 for the 100A … which also explains why proper batteries with CAN are a few grand more you really do pay for a proper bms…

Do you have CAN working on your bms? I’d be very surprised- but good luck with it. It’s very tricky to get CAN working properly- as mentioned before if your bms has it- unfortunately doesn’t mean it is programmed and talking to an inverter- you do need the software and all programmable parameters of your cells (there are almost 100 programmable paramaters on some Of the bms models!) They are notoriously easy to blow- and please please be careful- you are working with high currents - lethal. If you dont have experience or are qualified in electricity- you are playing with dangerous things. last bit of advice is for 300+ amp bank and single inverter you need the correct inline fuses - probably 400 amps- and at least 50MM battery cables- these are expensive. Thats part of the reason the 3 - 5kW lithium batteries are usually built as 100A- you can then use 35mm cables and 160A fuses- which are very common and affordable. Large high current banks are not recommended for home use- rather parallel smaller amp banks..

Unfortunately not:( cant find much detail on that device, but have a feeling it’s a RS485-serial/usb converter. So might “talk” to your axpert, but the intelligence comes from the bms side- and doubt the said bms will have the same level of detail to feed and control the inverter. There is no quick fix or easy way to fake “can/rs485” comms unfortunately. It is Very complicated to get right- the reason so much money is spent on certification for any specific brand of battery to be compatibly with the different inverter brands. The guys building batteries will tell you the same- it’s months and months of work/coding/testing etc If you want to future proof- get rid of the axpert, Buy something decent like a 5 or 8kW sunsynk/deye (full hybrid inverter) - and start with a battery like the am-2 hubble or similar.. efficiencies of hybrids vs - lets be honest and call the axperts what they are : “cheap and nasty” - is a long other topic…. Of course this all costs money- but if you look at backup power as a requirement for the next couple of years, rather invest in the correct kit now that will last 5-10years, have 5 & 10 Y guarantees- for 30% more upfront - or go as cheap as you can and in 2 years have to replace it all again… Whats that saying “goedkoop koop Is duur koop” - thats why these forums exist I suppose- for free advice from users who's already done it all (a few times)

This is where lithium replacement batteries require more understanding.. without CAN you have to set them correctly- never equalise a lithium battery. So for axpert type inverters without comms, or these batteries without comms just a basic bms, you have to follow the manufacturers specs. There should be a bulk or float or both V value, then perhaps something called absorbtion and also equalisation. Float is max the manufacturer says what is termed as “full” bulk is sometimes a little more. Equal and absorb must be the same, sometimes these could be “bulk”, and any setting around de sulphate/equalise every x days” should be disabled or set to 0. As an example on a custom 5kW 48V lithium and a sunsynk- the float for the specific battery and it’s bms and amount of cells are: 54V. Absorb and Equal both 57.6V, and days set to 0. The axperts name them differently- and your values will be different- but it’s important to set them correct. Remember a difference of just 2V on the top For lithium (so 50V vs 52V) is almoat 50% capacity! Same applies to a float of 13.5V might be 100% and 12.5V 40%…. this is why it’s important to understand why an inverter with CAN, and a battery with CAN Is worth it- you loose at least 30% usable capacity without it- something to consider perhaps when a “replacement” costs only 20% less …