Renogy 50ah lithium battery not accepting a charge

spending a lot of money right now revamping the van...might look at some method of battery monitoring in the not too distant future.
 
Cool...

Got some extra info over here... Including lithium stuff further down.


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Going to look at the type of balancing technology might be on the Renogy BMS. I.e passive or active. If it’s passive balancing this might be the reason my battery/s are becoming imbalanced. The cause of imbalance, in my case, is NOT allowing the battery to drain too low but possibly because it was nearly always kept topped up by solar panel .
 
fair comment with the solar - but how do you realy know without monitoring?

what size solar?

what controller?

what loads running over 24hrs?


are you sure that your solar is putting enough into the battery to overcome whatever loads are being pulled.


100w panel can get you 6A max in full sunlight - for only for 3hrs midday - and rolls off either side of that window.

and thats in summer only. . . spring/autmn/winter you get next to no power.


so without any monitoring of any kind i cant see how you can be certain about any of your assumptions. . . just because you have solar connected doesnt mean its working?


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got any pics of your panels? or controller?


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i still think you can resolve all of your unknowns by fitting a shunt monitor to the battery/s

it will show you exactly what solar is going in to your battery,

what loads are coming from your battery,

what the battery state of charge is.


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you can get a cheap one for £36 with a small display.





About this item​

  • Battery Condition - High precision Current detection. You can read the battery bank like a fuel gauge, and also clear note the battery status.
  • LCD displays - Large backlit LCD displays multiple battery information (voltage, current, consumed power and battery capacity)
  • Data storage - designed to automatically store the last testing data when the system shuts off Voltage Capacity - voltage range 8V-80V and current range 0-100A
  • Wide Application - It is suitable for mobile and portable equipment, balance cars, cleaning machines,e-bike, instruments, RV, Boat, Caravan etc.
  • 100% Satisfied Service - Sincerely hope our products could give you a good experience and some help. Within a month you purchase this product, you can enjoy a worry-free return service. And any questions feel free to contact us, we will try our best to help you.

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not you exact battery. . but a Renogy 48v 50ah BMS , but it shows the balance resistors and balance leads.

1718608811915.png


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this may be yours?


1718608975832.png1718608989683.png1718609011714.png



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"100Amp BMS By the markings anyway. Looks cheap as
Construction looks very tidy.
couple temp sensors just floating up top.

Sadly after only about 20 cycles the battery wont accept any more amps after it hits around 13.68V it just drops out completely. after fully charging it and full draining it multiple times it will not provide more then around 25Amps now. Thinking the BMS is triggering some sort of "High Voltage" cut off far lower than 14.6v

Was thinking of just buying a Daly BMS and trying to see if the BMS was the problem. Renogy Didn't ask for it back and just refunded me back the purchase. After many emails and test photos etc. and a small reminder of my legal rights. Was interesting to see they didn't want it back to test what went wrong. Perhaps they are aware of some defects in this particular model or batch. Any how, I'm not complaining as in the end they did right by me so i thought it might as well throw it up on here for others to have a look at the quality and configuration. Especially seeing as how I've watched So many of Will's tear-down videos."




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Hi all
I just had a similar issue with Renogy 50AH; they refused warranty claim, but I posted a review on Trustpilot and now they will refund. Battery is 10 months old in son's Triton, one of 2 installed in parallel and charged by DCDC charger. He left the 12V fridge on too long, overdischarged them, and then both batteries went open circuit. One reset with a Renogy 240V/12V lithium charger, the other did not.
Pulled it down as you did. First voltage measurement across the whiole cell bank was 5.7V. Very low. Because BMS would not reset, I trickle charged the cells at about 4A by connecting positive to positive terminal, and negative direct to the cell bank negative ie bypassed BMS. Discovered a big mismatch in cell bank voltages. Bank 2, 3 and 4 (from positive to negative order) are charging to 3.3V, bank 1 nearest positive terminal goes to over 4V, higher with higher charge voltages.
ie Pos terminal (Bank 1) 13.8V, end Bank1/start bank2 9.9V(3.9V drop) . Then an even 3.3V per cell bank till zero at the negative terminal.
BMS trips when the voltage gets uneven by more than about 0.3V.
I loaded the uneven bank 1 with a few 12V light globes pulling 1.7A while charging, and that equalised the bank voltages to keep the BMS in, but it will not charge the battery. I suspect all or most cells in bank 1 have a high internal resistance, and are cactus. No matter what I try, the BMS trips as soon as bank 1 gets to 3.5V, and the others will not come up above 3.3V.
Any comments?
thanks


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this looks like the balance section of the BMS. . . .

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but reading the above. . .

it looks like running the battery low triggers the BMS shutdown.

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TBH, it looks like a very early battery. . . . where lithium and BMS tech is still being developed.


it may be best to just fit a newer more modern 100ah version into the van.

and just pklay with this 50Ah pair on the bench for other bits.


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i think you will have no end of repeat problems unless you can 100% unsure that you keep the battery withing its charge range to prevent the BMS shut down.


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Really do appreciate your interest and provision of all this knowledge. I might go for that shunt on your link. https://amzn.to/4b7rNWI. How accurate are they?
Yes, that is the exact battery (Renogy 50AH) so it would seem many others have had the issue too and his experience is very similar to mine.
Renogy dragged their heels (4 weeks of frustration!!), until I started researching how to deliver a recorded letter setting out my legal rights under the Sale of Goods Act. Eventually it was by contacting them on eBay that I got a result...i.e new replacement battery.
Likewise, I offered to send the 1st battery back to them ...they didn't want it. I kept it then and cracked it open to start delving into the reasons it had stopped working. Then began my research into Lithium technologies..which has been interesting. It's good to have dialog with someone like you who is obviously well-read on the subject.

At least that might convince this post readers that it wasn't me draining and leaving the battery discharged that caused the issue.
I do regret not buying a 100aH bluetooth model...perhaps Fogstar would have been a better choice!
 
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not had one myself. .

but have seem others on here with them.

they are accurate enough for the purpose of having in the van.

like most they may struggle reading loads under 0.5A ( 500mA) - ie low power LEDs or USB chargers

but above that they are fine.


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if you get any drift in the reading - just fully charge the battery to 100%, that will auto re-callibrate the shunt back to 100%.

most manufactures say you should fully charge to 100% at least once every 1-3 months.

as in plugged into the mains charger with lithium profile for 24hrs,

or fully charged from solar, or dc-dc.

until the current going into the battery is less than 1% of the capacity. ( 1A for 100ah battery or 0.5A for a 50Ah) - then its considered fully charged.


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some install ideas





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Thanks anyway but I have a eBay cheapo shunt and lcd monitor that I have just rediscovered on my garage and that I binned because it was 50% inaccurate. Think, if I am going to use a shunt to monitor SOC, I would spend a bit more and know that I can rely on the results. @Dellmassive pointed out the Renogy one which is a good deal right now at £79.99
 
OK. I mostly topped off the cells in the battery below deliberately leaving 2 just short of full charge.

I wired in the equalising board and you can see from image that 2/3 and 3/4 leds are lit indicating balancing taking place.
Seemingly, on the wee board current is limited to around 1A between cells. So will leave running today and voltmeter check each array when all led lights go out which should be indication of balanced cells.

equilising board.jpg
 
OK. I mostly topped off the cells in the battery below deliberately leaving 2 just short of full charge.

I wired in the equalising board and you can see from image that 2/3 and 3/4 leds are lit indicating balancing taking place.
Seemingly, on the wee board current is limited to around 1A between cells. So will leave running today and voltmeter check each array when all led lights go out which should be indication of balanced cells.

View attachment 246519
awesome. . .

have you got a list of the cell voltages at the start?

c1
c2
c3
c4

then update them after the 12/24 balance period?
 
C1 = 3.4
C2 = 3.3
C3 = 3.2
C4 = 3.0

Put the battery back in the van
Managed to get my 2 x 100w solar panels wired to feed my Renogy dc-dc . Ran diesel heater to drawn down on battery.

Good to see then the DC-DC starting to top up battery then after 1.5 hours or so,indicating full charge (green led). The equaliser board then switched on cell 2-3 and cell 3-4 leds and is currently balancing cells. Will let it balance out and then report cells groups 1-4 4S voltages. Update you tomorrow
 
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whats the settings on the DC-DC?

is it a Renogy? do you have the BT2 adapter to get to the settings?

if not you can cycles the battery types. . .

i think BLUE is for Lifepo4?

just to get an idea of what the dc-dc is trying to raise the battery voltage too?
 
whats the settings on the DC-DC?

is it a Renogy? do you have the BT2 adapter to get to the settings?

if not you can cycles the battery types. . .

i think BLUE is for Lifepo4?

just to get an idea of what the dc-dc is trying to raise the battery voltage too?
I have set for 30amps. I have the BT 2 adaptor and app installed on my iPhone. Yes set blue on Renogy DC-DC. I have set the voltage level to 13.6v so hopefully that balances out at 3.4v per cell group
 
I have set for 30amps. I have the BT 2 adaptor and app installed on my iPhone. Yes set blue on Renogy DC-DC. I have set the voltage level to 13.6v so hopefully that balances out at 3.4v per cell group
that 13.4v charge voltage sounds a bit low?

the battery spec sheet calls for a charger voltage of 14.4v. ( from the sheet posted above)

(and i use 14.2v on all my lithium batteries and chargers.)

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if you wanted to go easy you could drop it to 14.2v for the bulk/absorption stages.


13.6v odd would be a float / maintenance charge.



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after your testing i could be worth running the recommended charge voltage settings. ?


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