Are my Lithium Batteries Faulty? (1 Viewer)

zac

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I have 2 sterling lithium 100ah batteries that were fitted 4 years ago, they were fitted professionally and have been working perfectly fine up until last week. Since January i have been running the motorhome when parked up outside my house using the batteries and then topping up when the batteries get to approx 65%. I have a victron battery monitor that i have been checking daily to ensure i keep an eye on levels etc and with just the alde heating running on gas (small amount of electric to power on) and the 360 degree camera system on 24/7 the total output of these are approx 20w. I also have a 150watt solar on the roof which i am sure will put a small amount back in when allowed (sunny days), on Friday evening i checked the BMV and it read over 70% charge but from the time i took that reading (23:30) the system the following morning sent me a text at 01:52 telling me that the voltage had dropped below 12v. In fact when i checked the battery monitor when i woke up the voltage was just over 6v. i checked the motorhome and nothing else has been left on and the victron BMV shows the output all the time as well.
So turned on the EHU and then charged the batteries back up to 100% which was odd as i am sure that when i turned the ehu on and checked the BMV the charged state change to 100% (i may be wrong but i think that's what happened). So to be sure i have been monitoring over the last couple of days and after i left the batteries to charge for the bulk of the day via EHU i turned off the electric again and took some screen shots via the BMV.

The heating system the past week has not come on due to it being quite warm where we are ie over the 6degrees

1st one was yesterday at 18:17 and shows the batteries at 99% and 13.08v with 19w being drawn (which will be the camera system as nothing else on aside from heating system set to Gas only but not cold enough to come on as that's only set to 6 degrees) and consumed ah at -3.8ah
2nd one taken 23:40 same evening and that shows 97% and 12.98v with 18w drawn and consumed ah at -11.3ah
3rd one this morning taken a moment ago at 09:35 and shows the batteries at 12.87v 4w being drawn and consumed ah at 23.3ah

i am sure that when i used to check this that the voltage was always near 13v no matter the state of charge and it didn't drop or am i making this up?

Something definitely not right with this as using a little under 20w should give me more than 3 days of usage with 200ah of lithium.

Any thoughts on this? i will call the company on Monday for some advice but in theory they should still be ok

IMG_1958.PNG IMG_1959.PNG IMG_1961.PNG
 
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Jan 27, 2018
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which was odd as i am sure that when i turned the ehu on and checked the BMV the charged state change to 100% (i may be wrong but i think that's what happened).
The heating system the past week has not come on due to it being quite warm where we are ie over the 6degrees

Any thoughts on this? i will call the company on Monday for some advice but in theory they should still be ok
The Bmv typicaly reverts to 100% when power has been disconnected. A better alternative is now available in the settings of latest version.(revert to last value)
Not knowing settings of the battery bms is it possible the batteries went to sleep or even momentarily disconnected the bmv and reset the SOC (durring one of the cold snaps) . This would now report incorrect SOC if you only charged for the odd 2 hrs, if it happenned more than once? This may be a contributing factor or i may be barking up the wrong tree.
At least this will shake the tree.
 
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zac

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The Bmv typicaly reverts to 100% when power has been disconnected. A better alternative is now available in the settings of latest version.(revert to last value)
Not knowing settings of the battery bms is it possible the batteries went to sleep or even momentarily disconnected the bmv and reset the SOC (durring one of the cold snaps) . This would now report incorrect SOC if you only charged for the odd 2 hrs, if it happenned more than once? This may be a contributing factor or i may be barking up the wrong tree.
At least this will shake the tree.
thanks for the reply, i have not changed the BMV settings since the install and i have attached a screen shot here which i hope are the ones you are referring too. It was not cold the night the battery discharged it was around 6-8 degrees over night. This is the first time it has happened but like always i am now concerned as we are due to be going away end of April and most of these are likely to be airs so will need the batteries in a good state. Also when i charged them back up the EHU was on for 5 hours before i disconnected it and the battery showed 100% again.

IMG_1962.PNG
 

Kannon Fodda

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I think some of those settings on your Victron BMV are incorrect for any lithium, not just Sterling. The voltage at 13.2 stands out given that a fully charged lithium resting is normally around 13.6V.
 
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Tombola

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I'd start with blaming the bmv or Bluetooth.
Did the batteries themselves shut off with low volt protection ?
Disconnect any source and get a volt meter on after a short while to get the reading.see if that matches the bmv...possible reset required..

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Lenny HB

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You want to turn off the "Battery start Syncronise" and change the Peukert exponent to 1.05 and as said the charge voltage is too low.

I would ignore the percentage charge reading, far better to go by the consumed ah and work it out yourself until you know how accurate the percentage reading is, it's difficult to get it right.
 
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zac

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You want to turn off the "Battery start Syncronise" and change the Peukert exponent to 1.05 and as said the charge voltage is too low.

I would ignore the percentage charge reading, far better to go by the consumed ah and work it out yourself until you know how accurate the percentage reading is, it's difficult to get it right.
Thanks I will change this settings, the actual output is only around 20watts of what is left using power. 200ah should last more than 3.5 days if only using 20watts. I know there is nothing else switched on. Also as each day goes by the voltage is dropping which I am not sure I have seen before as I am sure the voltage always used to be the same give or take. These are dropping like lead acid batteries
 
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Do not have Sterling batteries, but these are the settings we were told to use for our lithium battery monitoring

Peukert exponent: 1.05
Charged Voltage: 13.8V
Tail current: 4%
Charged detection time: 3m
Charge efficiency factor: 99%
 
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Dec 2, 2019
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Tail 4%? That’s wrong, if charge goes under 16a, the bmv wil re set to 100% prematurely. I set mine at 0.5% tail current, charge efficiency 99% and peukert 1.01. This gives me spot on percentage, and it’s not out even less than 1%. Also as already mentioned, turn off battery starts synchronised.
 
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zac

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I'd start with blaming the bmv or Bluetooth.
Did the batteries themselves shut off with low volt protection ?
Disconnect any source and get a volt meter on after a short while to get the reading.see if that matches the bmv...possible reset required..
it shut the motorhome control panel off due to it going low

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zac

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what should the voltage read with no EHU just running on battery as i seem to remember that it was always quite high with lithium but these now seem to be dropping voltage, ie its gone from 13.08v down to 12.8v after approx 12 hours?
I thought lithium's stayed at a certain voltage when not on EHU
 

Kannon Fodda

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Resting voltage for lithiums, fully charged should be around the 13.6V. One advantage of lithiums is their Voltage profile through their capacity range is fairly stable, one reason why using voltage as a guide to capacity is often inaccurate. Dropping to even 13.0V would suggest the Lithium battery is largely discharged.

You need to do some detective work to identify if this really is a battery problem, or something else. I suspect there is a draw on current, even a small shortcircuit, that is pulling everything down. It has the hallmarks of a relay or similar getting stuck open. If you have a decent clampmeter you may be able to start some testing.
 
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zac

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Resting voltage for lithiums, fully charged should be around the 13.6V. One advantage of lithiums is their Voltage profile through their capacity range is fairly stable, one reason why using voltage as a guide to capacity is often inaccurate. Dropping to even 13.0V would suggest the Lithium battery is largely discharged.

You need to do some detective work to identify if this really is a battery problem, or something else. I suspect there is a draw on current, even a small shortcircuit, that is pulling everything down. It has the hallmarks of a relay or similar getting stuck open. If you have a decent clampmeter you may be able to start some testing.
I am not relating the voltage to how much they are charged but more that there is an issue with them as i am sure they don't usually start to go down when not on EHU, i usually see a % charged in BMV but the voltage i am sure was always above 13v.

There is a draw on the current as i have some devices left on ie 360 camera system and the alde heating system but on gas only and only set to 6 degrees, . I will call the company that installed them tomorrow as i may need to take a trip to see if they can see what's going.
 
Dec 2, 2019
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what should the voltage read with no EHU just running on battery as i seem to remember that it was always quite high with lithium but these now seem to be dropping voltage, ie its gone from 13.08v down to 12.8v after approx 12 hours?
I thought lithium's stayed at a certain voltage when not on EHU
If it’s a fairly small load, you should se about 13.2-13.3v at 20Cdeg. Lower temperatures, or higher discharge could show a lower voltage.
What I would do, is disconnect one battery, fully charge to 14.4v then disconnect the charger and let it rest. Read the voltage next day, 13.2-13.4v it’s a healthy battery. I would repeat with second battery, fully isolated from van electrics. It can be done in situ, with external charger.
Once you eliminate the possibility of faulty battery, you can dig further, as in charging system, and shunt settings. Shunt definitely has bad settings, the reset if false SOC. I think you may have a combination of things that drift over time, and now it shows it’s head.
 
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zac

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If it’s a fairly small load, you should se about 13.2-13.3v at 20Cdeg. Lower temperatures, or higher discharge could show a lower voltage.
What I would do, is disconnect one battery, fully charge to 14.4v then disconnect the charger and let it rest. Read the voltage next day, 13.2-13.4v it’s a healthy battery. I would repeat with second battery, fully isolated from van electrics. It can be done in situ, with external charger.
Once you eliminate the possibility of faulty battery, you can dig further, as in charging system, and shunt settings. Shunt definitely has bad settings, the reset if false SOC. I think you may have a combination of things that drift over time, and now it shows it’s head.
ok, before i start changing things i will call the company that fitted it to ensure i am not just messing things up. There might be a reason why it was set when it was installed but it was a long time ago (4years). I don't like messing with electrics as i have no clue which is why i always rely on people that i trust.

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Dec 2, 2019
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ok, before i start changing things i will call the company that fitted it to ensure i am not just messing things up. There might be a reason why it was set when it was installed but it was a long time ago (4years). I don't like messing with electrics as i have no clue which is why i always rely on people that i trust.
If the settings are the ones you posted above, then the installer never set it properly for lifepo4. Many don’t even know those setting what it means, and what appropriate values to enter. Even standard victron preset for lifepo4, doesn’t even come close to reality. One cloud, and the reset to 100% soc is false, with stock settings.
Yes I agree, a visit back to the installer is best call.
 
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zac

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If the settings are the ones you posted above, then the installer never set it properly for lifepo4. Many don’t even know those setting what it means, and what appropriate values to enter. Even standard victron preset for lifepo4, doesn’t even come close to reality. One cloud, and the reset to 100% soc is false, with stock settings.
Yes I agree, a visit back to the installer is best call.
The settings was taken direct from the BMV this morning, i have never changed them as i would not know what i needed to change. To be honest i would never even go into that screen if it were not for the loss of power recently. That's when i noticed the drop in voltage with no EHU connected, i am hoping nothing else is wrong as these lithium's were very expensive and up until now they have been faultless.

I am going to charge them again now to ensure they are 100% then disconnect the EHU and see what it says tomorrow morning, i am pretty sure the voltage would of dropped overnight below 13v but will know for sure tomorrow.

Currently there is 275w going into the batteries from the EHU so it should not take long to charge them if they are at 12.9v which is what the BMV said it was.
 

Tombola

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I am going to charge them again now to ensure they are 100% then disconnect the EHU and see what it says tomorrow morning, i am pretty sure the voltage would of dropped overnight below 13v but will know for sure tomorrow.
when you do charge them, disconnect all loads and test the battery in the morning . you will have the answer then
 
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zac

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when you do charge them, disconnect all loads and test the battery in the morning . you will have the answer then
Am i thinking this incorrectly as even if there is load on the batteries (20watts) the voltage should still not drop below 13v and if this happens does this not point to an issue with the actual batteries themselves or am i just being to simplistic?
 

Tombola

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Am i thinking this incorrectly as even if there is load on the batteries (20watts) the voltage should still not drop below 13v and if this happens does this not point to an issue with the actual batteries themselves or am i just being to simplistic?
maybe, maybe not, we dont know if the victron is reporting properly (it isnt atm)
but the only way.... as others have said is test the battery alone, this will tell you the condition of that, then if the looks ok you can concentrate on other things.
I cant comment on the BMV settings as I dont use it any more , but what others have said seems to stack up.....I rely on the bluetooth batteries report themselves now.

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zac

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maybe, maybe not, we dont know if the victron is reporting properly (it isnt atm)
but the only way.... as others have said is test the battery alone, this will tell you the condition of that, then if the looks ok you can concentrate on other things
ok thanks for the reply, i will see how it goes.
 
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Tail 4%? That’s wrong, if charge goes under 16a, the bmv wil re set to 100% prematurely. I set mine at 0.5% tail current, charge efficiency 99% and peukert 1.01. This gives me spot on percentage, and it’s not out even less than 1%. Also as already mentioned, turn off battery starts synchronised.
Interesting shall do a bit of research now (y)
 

Kannon Fodda

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zac

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I was never able to make it work, but if you have Sterling Power Batteries that are marked with the Bluetooth logo, and an Android based phone, you should be able to use an app to connect to the battery bms. If so that will tell you if the battery voltage, and the Victron BMV are in agreement on things like voltage. https://www.bimblesolar.com/docs/Batteries/Sterling Power Lithium Bluetooth BMS .pdf
I dont think mine has bluetooth as they have never come up when searching for other bluetooth devices in the motorhome, i will see what the part no is when i take a look in the morning and double check but never seen them before.
 

Kannon Fodda

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If they do have bluetooth there will be a little sticker on the top of the battery. Mine was a silvery shiny thing near to one of the battery handles and terminal. But I couldn't get it to connect so may be a red herring anyway.
 
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Jan 27, 2018
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to me your settings look more standard LA than lithium, but now more knowledgable people are on the game. Glad to see youre getting some "stirling advice" from Raul (pun intended)
 
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zac

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I can only get to one of the batteries to test without dismantling a lot that's on top of it but with everything off inside the motorhome and no EHU connected the BMV reads 13.25v and a multi meter reads 13.26v. I would assume that by this the BMV is correct in what it reads.
Will check it in the morning to see what it says.

DBC32999-41BD-49C0-9C44-D2F94F22C0B5.png
 
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zac

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Checked this morning and bmv reads 13.18v with no load. A small drop overnight, where does that leave me as when i put load through it then drops the voltage which is not correct for lithium's?

A1245C43-8076-41C0-A15B-1B506B5727D8.png
 

Lenny HB

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So it looks like something is draining them and if it's not registering on the BMV it would point to something being directly connected to the batteries bypassing the shunt.
I think you need to check the wiring to both batteries carefully.

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