EG4 3000 battery discharging/detection issue

[1776_Lobo]

Greetings all- First time poster- happy to have found this forum. I live off grid in Virginia horse country in my 2012 Cedar Creek fifth wheel - all solar and genset- no shore/utility power and lovin life!

My system- EG4 3000 charger/inverter- 3200 watts of solar panels- 4- 12v LiFePO4 400 AH Sokerdy battery bank run in series for a 48v system. Champion 4500 watt inverter/gen set as needed for charging batteries in no/low sun.

Installed the system about a year ago- overall has run pretty well until now. I have electricity if I run gen set (connects to EG4 charger) and have power in my rig however energy I cut off genset charger shows low voltages in battery bank at times such as 20v but at times would also read up to 58v- regardless the reading when genset cut off electricity to the rig died.

I was getting BP message on screen which I understand means no connection to batteries. Not the first time I’ve seen this warning- system has at times been glitchy in the past and flashed the BP code.

Called SS yesterday ( Not open today- Sunday) and they asked me to perform a continuity test at DC battery input- that checked out ok so I called back and was advised to remove my batteries (big pain in the rear due to access) and test individual voltages after removing series connections - 3 batteries tested at 13.16v and the 4th tested at 12.8v so it looks as if my batteries are indeed taking a charge and are fully charged- is the .36v variation from the one battery relative to the other three enough variation for the charger/inverter to not recognize the series as ‘one battery’ as SS tech put it?

Also while having this battery discharge or lack thereof issue) and running on the genset the power will cut off for about 10 seconds and charger/controller gives load warning beep- sometimes this can happen every half hour or so while on genset.

I’m currently trying to boost the voltage of the 12.8v battery a bit using a trickle charger (want to charge slowly and only bump voltage up to 13.16 level of other three batteries) - Ideally I’d like to use a variable voltage charger that disks into 13.16 volts exactly but I have no such charger.

I’m really thinking this is the EG4 charger having the issue.

Any constructive input/suggestions would be much appreciated.

I’m also going to expand my system very soon- was considering DOJ ling the battery bank- doubling panels and upgrading to the newer EG4 6000 charger- I’m assuming if I want to increase battery capacity by 50% I could add 2-24v 200AH LiFePo4 batteries in series with one another and connected parallel with existing battery bank. Any flaws in my logic? I guess I could also buy 4- 12v @100 AH in series and then in parallel with existing 48v battery bank.

Please forgive my ignorance or lack of knowledge/communication skills regarding solar systems as I’ve only really studied them for the past 1.5 years.

Thanks

 

[BentleyJ]

Its likely that the battery with the low voltage is shutting down due to the BMS sensing a low cell. Since its a single series string if one BMS disconnects then the inverter sees an open circuit.

Would recommend charging all 4 x12V batteries to the same voltage when connected in parallel to re-balance them. Should also let them float at 14V for several hours so the internal balancing circuit can work on individual cells.

If you upgrade to 48V then its highly recommended to use a 48V battery so the BMS has access to all 16 cells and can keep them balanced.

 

[1776_Lobo]

Its likely that the battery with the low voltage is shutting down due to the BMS sensing a low cell. Since its a single series string if one BMS disconnects then the inverter sees an open circuit.

Would recommend charging all 4 x12V batteries to the same voltage when connected in parallel to re-balance them. Should also let them float at 14V for several hours so the internal balancing circuit can work on individual cells.

If you upgrade to 48V then its highly recommended to use a 48V battery so the BMS has access to all 16 cells and can keep them balanced.

 

[1776_Lobo]

Thanks Wizard- I’ll give it a try-

Do you suspect I’ll have to replace the low voltage battery or is this balancing procedure most likely to take care of the problem long term?

 

[BentleyJ]

Good chance that a top balance at 14V for several hours will correct the problem, until the batteries get out of balance again. If there is not a Bluetooth connection available with the BMS then there is no way to view individual cell voltages without opening up the battery case.

Best you can do is try the top balance procedure and put the batteries back in service.

 

[1776_Lobo]

Roger that- thanks again!

 

[1776_Lobo]

Good chance that a top balance at 14V for several hours will correct the problem, until the batteries get out of balance again. If there is not a Bluetooth connection available with the BMS then there is no way to view individual cell voltages without opening up the battery case.

Best you can do is try the top balance procedure and put the batteries back in service.

Hey Wizard- sorry to bother you again- have had batteries in parallel charging on 12v charger @ 2amps- lower setting of two( , high./faster charge is 6 amps) - for several hours now- seems to have topped out at 13.19v. I ordered a variable charger that will arrive tomorrow. I also have a 48v charger- I don’t guess I can hook up the 48v charger and closely monitor until they get to 14v as you suggested? Is getting to that 14v so critical that I should wait for that variable voltage charger before reinstalling batteries? Thanks again

 

[1776_Lobo]

Hey Wizard- sorry to bother you again- have had batteries in parallel charging on 12v charger @ 2amps- lower setting of two( , high./faster charge is 6 amps) - for several hours now- seems to have topped out at 13.19v. I ordered a variable charger that will arrive tomorrow. I also have a 48v charger- I don’t guess I can hook up the 48v charger and closely monitor until they get to 14v as you suggested? Is getting to that 14v so critical that I should wait for that variable voltage charger before reinstalling batteries? Thanks again

Actually right after posting they had increased to 3,20v - I’m pretty sure I should keep the charger on the slower 2 amp setting correct? Thanks

 

[1776_Lobo]

Actually right after posting they had increased to 3,20v - I’m pretty sure I should keep the charger on the slower 2 amp setting correct? Thanks

Then I was browsing my LiFePO4 battery manual and learned I shouldn’t be using a standard battery charger which I was- hope I haven’t done any damage- ordered a LiFePO4 specific 14.2 v charger arriving in the AM

 

[BentleyJ]

Each battery is 100Ah I believe? They can be safely charged at up 20 Amps.

Yes, you need to wait for the new charger and get all 4 batteries up to a minimum of 13.7V and hold for several hours. 14.0V would be better.

 

[BentleyJ]

The lower voltage charger will not damage the batteries but they will never fully charge and the BMS cannot balance cells properly.

14.2V is fine also.

 

[1776_Lobo]

The lower voltage charger will not damage the batteries but they will never fully charge and the BMS cannot balance cells properly.

14.2V is fine also.

Thank you Bentley- or do you prefer Wizard?

Thanks for the feedback- got the LiFePO4 smart charger delivered at 5AM- stayed under 20 amps while charging- after charger indicated my parallel array was fully charged

I disconnected charger and then disconnected parallel connections and individually tested- all but one battery(ID as # two) tested at 13.26v where number two tested at 12.86.

Put them back in series and reconnected back to EG4 hoping for a miracle that wasn’t delivered- I’ve ordered a new 12v 400ah battery but am told it arrives in late June- I’m off grid and w/o my battery bank if I want power I run a genset or on sunny days rely on PV. I’ve written to EG4 after contacting SS and being told I was SOL - asked EG4 if there’s any possible work around in settings adjustment on charger with one limping battery to get something, even if only 1/2 power in the interim. Sent via email and awaiting reply.

I also asked them if I could temporarily grab a 12v 100ah off the shelf somewhere local and connect with the 3 working batteries , (each 4x larger than it) it as a substitute for the defective #2 battery until replacement arrives.

SS said don’t do it could cause damage however I had little faith in the knowledge or commitment of this nice young twenties something fella.

Any input would be much appreciated Jared and thanks for your help so far. All that being said I love living off the grid and it is what it is- I’ll get it fixed but the one thing that doesn’t change is my FTM attitude towards utility power- call me a trailer park Tesla if you will-

 

[BentleyJ]

As long as the 12V battery (specifically the BMS) chosen is compatible with the 48+Volts when connected in Series you can use another brand. Refer to the specification sheet, it should say if series connections are allowed.
In fact, you could even use a 12V battery with a different capacity, preferably a higher Ah rating. Of course the system would still be limited to the usable capacity of the lowest battery in the string.

 

[BentleyJ]

As to the other question, "Solar Wizard" and other various titles are something that are assigned by the forum administrators just for fun. Most of us don't pay much attention. If you are looking for a response from someone in particular best to use @ForumMemberName or a Private Message.

 

[1776_Lobo]

As to the other question, "Solar Wizard" and other various titles are something that are assigned by the forum administrators just for fun. Most of us don't pay much attention. If you are looking for a response from someone in particular best to use @ForumMemberName or a Private Message.

Thanks for the heads up on protocals - Yes I assumed ‘solar wizard’ is an acquired rank- sounds like a relatively high one to me.

So I have the new 12v/400ah battery on the way and as far as I know I’m not able to buy a battery of that size off the shelf locally but I can get for $300-400, a 12v 100ah battery- which is 1/4 the capacity of the other three. Assuming the smaller new battery states it can be run in series do you think it would create the 48v needed to get the EG4 to allow discharge as needed? I’d buy the same 12v 400ah battery to replace the bad one today if I could- ordered one today and not expected to arrive until late June so I’m looking for a temp work around.

Note to self- maybe always have a 5th battery in reserve.

 

[BentleyJ]

One of the properties of LFP chemistry is its very flat voltage vs. SoC curve between 10% and 90% SoC. So the smaller capacity will not prevent the new battery from contributing its share of the 51.2V nominal series string.
But as stated earlier, the system will be limited to about 90Ah which is the usable capacity of the smaller battery. 90Ah x 51.2V = 4.6kWh

 

[1776_Lobo]

One of the properties of LFP chemistry is its very flat voltage vs. SoC curve between 10% and 90% SoC. So the smaller capacity will not prevent the new battery from contributing its share of the 51.2V nominal series string.
But as stated earlier, the system will be limited to about 90Ah which is the usable capacity of the smaller battery. 90Ah x 51.2V = 4.6kWh

Roger that- so it’s a viable bandaid that puts me at 25% capacity - unless I can create an expedited shopping scenario on the replacement battery coming I may well implement this bandaid- grateful for you sharing your knowledge!

 

[1776_Lobo]

Hey Bentley - why shouldn’t I just tear open the bad battery- ID the defective cell and order a replacement? I’m thinking that’s a much faster solution than waiting on a 75lb battery and when it does arrive I’ll the have a legit back up. Your thoughts?