Lithium battery discharged for no reason

[Steve and Julie]

We have a 280 ecoworthy lithium battery that I got fitted nearly a year ago. We were away for Easter at Ripon racecourse .we used the inverter a few times and lights and the water pump. It was down to 73% . We went out to the clubhouse and on our return as we entered the van could hear a buzzer which was the inverter alarm. Checked the app for the battery was down to 0%. Nothing was left on while out. I used our bluetti power station with a smart charger we had to put some charge back in whilst we slept. It had put 19% back into the battery. Any idea what happened as very annoying

 

[jeffmossy]

If you leave your invertor on and leave your fridge freezer on auto or electric setting, that would probably be your problem,

 

[Steve and Julie]

Thanks for the reply Jeff. But I'm sure the fridge was on gas as the inverter only power's one bank of sockets. I thought it might be a cell but the app doesn't show any warnings

 

[MERL]

I obviously don't know how long you were out of the van but using up 73% of a 280Ah battery in a short period of time would result in the generation of a considerable amount of heat. I suspect that wherever you got the reading of 73% from it was inaccurate for some reason. The clue would have been the actual battery voltage when you left the van to go out. Do you have any historical voltage data recorded on any of your items?

 

[Steve and Julie]

We were out of the van for around 4 hours. I got the reading from the eco worthy app I think the voltage was definitely 13. Something and the autotrail display was saying good if that helps

 

[Nabsim]

That's a massive amount of power to use in 4 hours. Personally I wouldn't take notice of what any of the battery apps say and would fit a decent shunt. You would still have been at zero if its is flat but it wouldn't have said 73% when you went out. Well not unless you were running something using over 50A per hour while out

 

[MERL]

I think the voltage was definitely.....

Sounds like an Oasis track..... definitely maybe.
If the Autotrail display is the same one that's used for lead acid batteries then that will mean virtually nothing.
I don't know how the BMS within the Ecoworthy batteries calculate the capacity but I know that most coulumb counting shunts have a minimum threshold of current below which they don't register any drain at all, if the battery sits uncharged for long periods of time with a very.light load such as a vans PDU then over time the battery can get quite depleted and the shunt will still display 100%..... obviously leading to you thinking that the battery is way way more charged than it really is. As I've said it's impossible to say without a reliable voltage measurement at the point you left the van.

 

[Steve and Julie]

Thanks for the replies all I know is the battery was fully charged according to the app when we arrived and we didn't really put much strain on it and it has never dropped below 50% on previous longer trips. On a previous Van with a lithium battery the same thing happened but it showed a fault on the app and it was a dodgy cell. But this battery app isn't showing any faults

 

[YeoBlade]

Being fully charged, in the app, maybe inaccurate. Do you have a calibration setting when DEFINITELY fully charged?

 

[MERL]

That's a massive amount of power to use in 4 hours. Personally I wouldn't take notice of what any of the battery apps say and would fit a decent shunt. You would still have been at zero if its is flat but it wouldn't have said 73% when you went out. Well not unless you were running something using over 50A per hour while out

Exactly Neil, using that amount of power in just four hours you'd have noticed something when returning. You can't dissipate that much energy inside a camper in 4 hours without some sort of smell or something being very hot.
Almost certainly It'll be the app not being correctly calibrated.

 

[colinm]

If you are sure nothing was on in the few hours you where away from van this points to the 73% being a error. This then poses the question as to why the SOC might have been much lower, it points towards you using more power over the weekend than you are putting back in. How much solar do you have, and if you have the invertor permanently on do you know how much it draws on standby.

 

[Steve and Julie]

We have 160 Wats of solar. But I have noticed since installing a new victron controller it always thinks the battery has 14 volts and is permanently on float. When the inverter is on standby the app doesn't show any drain just when something is on.

 

[molly 2]

Have a word with whoever fitted the battery , was it a full fit with new chargers etc or was it a drop in .

 

[wildebus]

We have 160 Wats of solar. But I have noticed since installing a new victron controller it always thinks the battery has 14 volts and is permanently on float. When the inverter is on standby the app doesn't show any drain just when something is on.

Sounds like you have not got things connected right. Have you checked the battery voltage on the app when it is dark? (or more precisely probably, can you even connect to the controller when it is dark?) I would guess you don't have a connection to the battery on the solar controller.

 

[MERL]

since installing a new victron controller it always thinks the battery has 14 volts and is permanently on float.

That could be excessive cable resistance between controller and battery, due to the cables too thin for the distance involved.

When the inverter is on standby the app doesn't show any drain

As I mentioned previously, it appears that the BMS doesn't 'see' low currents, so these don't get counted and subtracted from the battery capacity, this leads to the app information being wrong and in your case way off and completely inaccurate. Your inverter standby current will actually be quite significant, somewhere between 300mA and an amp, it's a poor design that doesn't count that sort of current. You should probably consider getting a shunt fitted. I have the cheap and cheerful Ai-li shunt and that displays currents of just a couple of milliamps counts current down to approx 50mA.

 

[Steve and Julie]

Sounds like you have not got things connected right. Have you checked the battery voltage on the app when it is dark? (or more precisely probably, can you even connect to the controller when it is dark?) I would guess you don't have a connection to the battery on the solar controller.

Just checked the solar controller it's saying off with 7.6 volts

 

[Steve and Julie]

That could be excessive cable resistance between controller and battery, due to the cables too thin for the distance involved.

As I mentioned previously, it appears that the BMS doesn't 'see' low currents, so these don't get counted and subtracted from the battery capacity, this leads to the app information being wrong and in your case way off and completely inaccurate. Your inverter standby current will actually be quite significant, somewhere between 300mA and an amp, it's a poor design that doesn't count that sort of current. You should probably consider getting a shunt fitted. I have the cheap and cheerful Ai-li shunt and that displays currents of just a couple of milliamps counts current down to approx 50mA.

I just changed over the old pwm controller to the victron one using the same cables.
Sorry for my stupidity but don't know what a shunt is but appreciate all your advice

 

[Steve and Julie]

Have a word with whoever fitted the battery , was it a full fit with new chargers etc or was it a drop in .

Hi baz I originally changed over the battery which was in the outside battery locker. But have since got it refitted to under the lounge seating by a auto electrician

 

[wildebus]

Just checked the solar controller it's saying off with 7.6 volts

OK, you might be getting some power to the solar panel with street lighting? enough to keep it alive enough to connect to? (It will say 'off' as the panel voltage will be less than 1V above the battery reading*)
The way the Victron SmartSolar MPPT controllers work, if you don't have a battery connected, the solar controller works like a Power Supply and the voltage reported on the battery side is not actually the battery but is the generated output of the controller. You will be seeing whatever the charge voltage is configured for in the settings.


* If no battery connected, then 'battery reading' = charge voltage setting

I just changed over the old pwm controller to the victron one using the same cables.
Sorry for my stupidity but don't know what a shunt is but appreciate all your advice

When you connected up the new Victron, did you notice the terminal connection order was different?
Just about every solar controller has a POS NEG POS NEG order. HOWEVER, Victron controllers have a POS NEG NEG POS order. Keeping the same order on new as on old would explain why you have no battery being seen. Fortunately, you can reverse the voltage on the inputs on a Victron controller and it will have zero effect (other than not working) and swapping them to correct order will get it working.

 

[Steve and Julie]

OK, you might be getting some power to the solar panel with street lighting? enough to keep it alive enough to connect to? (It will say 'off' as the panel voltage will be less than 1V above the battery reading*)
The way the Victron SmartSolar MPPT controllers work, if you don't have a battery connected, the solar controller works like a Power Supply and the voltage reported on the battery side is not actually the battery but is the generated output of the controller. You will be seeing whatever the charge voltage is configured for in the settings.


* If no battery connected, then 'battery reading' = charge voltage setting



When you connected up the new Victron, did you notice the terminal connection order was different?
Just about every solar controller has a POS NEG POS NEG order. HOWEVER, Victron controllers have a POS NEG NEG POS order. Keeping the same order on new as on old would explain why you have no battery being seen. Fortunately, you can reverse the voltage on the inputs on a Victron controller and it will have zero effect (other than not working) and swapping them to correct order will get it working.

Will check tomorrow that I have wired it correctly thanks for the help