Uhome LFP 2400 Voltage Falling Under No Load Conditions

propnut

Until solid state batteries become real all current rechargeable tech uses a liquid or gel electrolyte. When this gets too cold it resists the flow of electrons degrading battery performance, hence why EV's lose up to 30% range in winter.

However that may or may not be your problem as "strange" isn't much to go on ?

Alnat1

I don't have the technical knowledge and language to explain unfortunately but simply knowing that my battery won't perform as well in the depths of winter is probably enough for me. 

sb1710

propnut said:

sb1710 said:

So I've got the vendor looking at the Uhome batteries for me with Aoboet to confirm that there is no issues with the packs.

The issue i have is that the installer (who did a great job, hint of sarcasm there) didn't get the Uhome batteries configured online and simply buggered off and its only recently that the second home visit the installer configured these for me.

However i am still awaiting the account details!!!! Spoke again on the phone today to remind them.

Once in hand i will perform the battery disconnection test and see hopefully the same result as you, with very little in terms of self-discharge.

I'm very keen to know what the secret to this fix is once you've checked for repeatability!

I put the batteries online myself and created my own account because, like you, my installer didn't do it or if they did they never shared that with me. The only thing they did was set up the Luxpower account which I don't use anymore. I have isolated my system from the internet and manage it from the app. WHY you may ask...well I discovered through this process that they have changed their methodology from one of "let the customer control how they use the equipment that THEY paid a fortune for" to "Who cares what they have set, when it reboots let's make sure it reverts to defaults. This is apparently to make their lives easier in case customers make "erroneous" changes that cause them trouble tickets.

Certain changes are sticky e.g. Charge priorities but others like some of the AC Charging parameters get set back to default. Now I don't know about you, but after spending a good chunk of change on this stuff I as an engineer, take serious exception to that mindset. That's like buying a car, setting your seat position memory but then finding each morning you start it, it has forgotten those settings because whilst it was doing an OTA the manufacturer decided you were too stupid to know where you wanted your seat

propnut said:

sb1710 said:

So I've got the vendor looking at the Uhome batteries for me with Aoboet to confirm that there is no issues with the packs.

The issue i have is that the installer (who did a great job, hint of sarcasm there) didn't get the Uhome batteries configured online and simply buggered off and its only recently that the second home visit the installer configured these for me.

However i am still awaiting the account details!!!! Spoke again on the phone today to remind them.

Once in hand i will perform the battery disconnection test and see hopefully the same result as you, with very little in terms of self-discharge.

I'm very keen to know what the secret to this fix is once you've checked for repeatability!

I put the batteries online myself and created my own account because, like you, my installer didn't do it or if they did they never shared that with me. The only thing they did was set up the Luxpower account which I don't use anymore. I have isolated my system from the internet and manage it from the app. WHY you may ask...well I discovered through this process that they have changed their methodology from one of "let the customer control how they use the equipment that THEY paid a fortune for" to "Who cares what they have set, when it reboots let's make sure it reverts to defaults. This is apparently to make their lives easier in case customers make "erroneous" changes that cause them trouble tickets.

Certain changes are sticky e.g. Charge priorities but others like some of the AC Charging parameters get set back to default. Now I don't know about you, but after spending a good chunk of change on this stuff I as an engineer, take serious exception to that mindset. That's like buying a car, setting your seat position memory but then finding each morning you start it, it has forgotten those settings because whilst it was doing an OTA the manufacturer decided you were too stupid to know where you wanted your seat. 

Fully agree with you on the mindset of the reseller / local agents, they don't share key pieces of knowledge to educate their customers who like myself are genuinely interested (and likely much more educated and hands on than some of the installers!)

I’ve also spent a little more time scanning through the MSE forums to find numerous other examples of people citing the issues with their batteries loosing charge amongst other things!

I'm going to allow access to the Lux servers for the first year or so and check that the system is working correctly (whilst under the UK legal requirements for a warranty) and after that I may well remove the remote IP address to the Lux Server (8.208.83.249) from the dongle and keep the local TCP server which I use to control and monitor my system using Home Assistant, I don’t really use the Lux Android app. My system dumps power to the grid in summer (when generation is over ~13kWh), so I’ve set up a automation to switch on a solar immersion controller when the batteries are above 99% SoC to heat my water tank (~10kWh) so very little gets put back to the grid. Hopefully this summer my gas and electric usage should be almost zero for around 4-6 months (weather dependant).

Like yourself I’m an engineer and a tinker (with practical applications in mind). You may or may not be aware that there is a way to keep you system settings (after a reboot) and also allow the equipment to be connected to the Lux Servers (if you wanted). There are a few people on the forums that have developed some brilliant tools to access and control the Lux inverters such as the lxp-bridge and HA integrations. https colon slash slash community.home-assistant.io/t/luxpower-ac-inverter-integration/283656

I’ve spent that last couple of months setting up a RPi 3 using Home Assistant with all my smart home tech and the Lux Inverter integrated in there too, a single app for everything and local control (mostly) so I could almost disconnect all these Chinese servers that have access to my home network!

Anyway thanks again for the thoughts and ideas, I should have considered some of these things you pointed out … but with a busy job and family life don’t have the time these days!

propnut

sb1710 said:

Fully agree with you on the mindset of the reseller / local agents, they don't share key pieces of knowledge to educate their customers who like myself are genuinely interested (and likely much more educated and hands on than some of the installers!)

I’ve also spent a little more time scanning through the MSE forums to find numerous other examples of people citing the issues with their batteries loosing charge amongst other things!

Have you had any feedback from them. Your last post before this one said you were getting a new battery, has anything progressed after that ?

As you say we aren't the only one to have noticed this and some of the posts I have found go back a few years so clearly nobody is getting answers. 

sb1710

propnut said:

sb1710 said:

Fully agree with you on the mindset of the reseller / local agents, they don't share key pieces of knowledge to educate their customers who like myself are genuinely interested (and likely much more educated and hands on than some of the installers!)

I’ve also spent a little more time scanning through the MSE forums to find numerous other examples of people citing the issues with their batteries loosing charge amongst other things!

Have you had any feedback from them. Your last post before this one said you were getting a new battery, has anything progressed after that ?

As you say we aren't the only one to have noticed this and some of the posts I have found go back a few years so clearly nobody is getting answers. 

New battery installed and auto-restart function fixed, however no change to voltage dropping (knowing what I've gained from our discussions that wasn't likely to change).

In terms of the reseller / agent I've been persistent with them and have been assured that I will get an update on the Uhome battery health "after Chinese new year".

In tandem with the external enquiry I've made a little wemos mini d1 power monitor to clamp on to the battery cables for the Lux / Uhome system in order to monitor the power. Mainly to see what happens when the BMS disconnects and observe what the latent power dissipation to see why the Lux system triggers a top up when the pack voltage gets to 49v.

As soon as I get some information I will share (assuming I get some answers).

sb1710

Finally got around to getting some measurements of latent power consumption of the lux ACS 3600 in standby mode just after switching from discharge mode ...

My system with with 4 Uhome LPF 2400 is located in a cool garage, approximately 6 degrees Celsius at the moment.

Coming in around 33 watts, equating to 0.8 kWh per day or approximately 10% of my system capacity.

So apparently Aoboet are currently developing a new app for battery monitoring of the Uhome packs. The local agent has told me that the app (Android / iOS) is going through checks before being released / available for end users.

Let's see if I eventually get the account details for the new app to check the battery health. If not I'll be resetting and putting them online myself and trying to avoid any more fruitless dialogues!

propnut

sb1710 said:

Finally got around to getting some measurements of latent power consumption of the lux ACS 3600 in standby mode just after switching from discharge mode ...

My system with with 4 Uhome LPF 2400 is located in a cool garage, approximately 6 degrees Celsius at the moment.

Coming in around 33 watts, equating to 0.8 kWh per day or approximately 10% of my system capacity.

So apparently Aoboet are currently developing a new app for battery monitoring of the Uhome packs. The local agent has told me that the app (Android / iOS) is going through checks before being released / available for end users.

Let's see if I eventually get the account details for the new app to check the battery health. If not I'll be resetting and putting them online myself and trying to avoid any more fruitless dialogues!

That marries up with the losses I saw as well which are ridiculous especially in winter. You lose 10% of your free solar energy only to have it replaced from the grid ???? A bit self defeating right ? The current Uhome app (NOT to be confused with the Aoboet app) seems to work fine. You can get some very detailed info from it.

GAJ59

Hi All

I have this problem too, and have been pursuing it for a while. Am I glad I found this thread! 

In October 2022 I installed 3 AOBOET Uhome LFP 2400s and a LuxPower 3600ACS inverter (contractor Home Energy Group).

Here's my problem, to which I am trying to get an answer from HEG of course

I think I am seeing a 20-30% difference between charge capacity and discharge capacity of my batteries. The data I have is total rectified, total charge total, discharge and total inverted. The large difference arises between the charge & discharge figures (which I wasn't expecting). There is of course a small % loss on rectification and an even smaller loss on inversion (which I was expecting).

I thought I was buying 6.5 kWh of usable capacity (90% DoD on 3x 2.4 kWh batteries). That's what I sized my requirement on and made my payback calculations against.

But whenever I look at any single 'closed cycle', where the battery charges from 11% to 100% and then discharges back to 11% there is this large difference, so the usable capacity is actually significantly less than 6.5 kWh, say 4.5-5.2 kWh. This is frankly disappointing. These cycles are all within 24 hours - I understand that a fully charged battery can't be expected to hold its charge indefinitely, but surely a normal cycle within a 24 hour period should not be an issue.

The total cumulative discrepancy so far is 82.1 kWh out of a total charge of 284.3 kWh, ie only 71% of what I would expect.

What differences are you guys seeing between your most recent eChgAll and eDisChgAll figures?

Today I've been emailed a firmware upgrade package, and will be sent a CAN cable with which to install from a laptop? It looks a very involved procedure.

I'd appreciate anyone's thoughts on this.

Many thanks, Graham

propnut

GAJ59 said:

Hi All

I have this problem too, and have been pursuing it for a while. Am I glad I found this thread! 

In October 2022 I installed 3 AOBOET Uhome LFP 2400s and a LuxPower 3600ACS inverter (contractor Home Energy Group).

Here's my problem, to which I am trying to get an answer from HEG of course

I think I am seeing a 20-30% difference between charge capacity and discharge capacity of my batteries. The data I have is total rectified, total charge total, discharge and total inverted. The large difference arises between the charge & discharge figures (which I wasn't expecting). There is of course a small % loss on rectification and an even smaller loss on inversion (which I was expecting).

I thought I was buying 6.5 kWh of usable capacity (90% DoD on 3x 2.4 kWh batteries). That's what I sized my requirement on and made my payback calculations against.

But whenever I look at any single 'closed cycle', where the battery charges from 11% to 100% and then discharges back to 11% there is this large difference, so the usable capacity is actually significantly less than 6.5 kWh, say 4.5-5.2 kWh. This is frankly disappointing. These cycles are all within 24 hours - I understand that a fully charged battery can't be expected to hold its charge indefinitely, but surely a normal cycle within a 24 hour period should not be an issue.

The total cumulative discrepancy so far is 82.1 kWh out of a total charge of 284.3 kWh, ie only 71% of what I would expect.

What differences are you guys seeing between your most recent eChgAll and eDisChgAll figures?

Today I've been emailed a firmware upgrade package, and will be sent a CAN cable with which to install from a laptop? It looks a very involved procedure.

I'd appreciate anyone's thoughts on this.

 Many thanks, Graham

Firmware upgrade for what? The batteries or the Lux unit ?? The batteries are a claimed 2.4kw but according to Uhome useable is only 2.2Kw which equates to 92% DoD so if at 90% then = 2.160kw x 3 = 6.48kw then the inverter os 95% efficient (claimed) so now we are down to 6.2kw. Now this thread deals with observed losses in standby mode which are very obviously also occurring when in use but less obvious which = another +-10% so 5.5KW. So more or less what you are seeing. So yes rubbish to say the least. But I learned when building my own off grid system for camping a few years ago that ALL these manufacturers  use fictitious headline figures.

I have seen 6.2 kw discharge once but that was on a very sunny day but how true that figure is is anyone's guess. But also that is skewed because it does not necessarily correlate to total battery capacity. If the wife used the various appliances during the day and the battery recharged in between then come nighttime it would be the cumulative total of the absorbed charge vs discharge during the course of the day

GAJ59

Thanks propnut. Sorry - firmware is for the batteries. No explanation of what it's supposed to achieve, just an involved process including crawling round the loft with my laptop! I've invited them to explain what it does and to do it remotely themselves under the warranty.

I understand your final point - it would be theoretically possible to fully charge the batteries more than once in a day, just like filling your petrol tank more than once in a day.

But I'm seeing more than the +-10% you mention - currently close to 30% loss (301.9 kWh -212.2 kWh, see below). I'd love 10%!

For my headline "what's wrong with this picture?" data to my supplier I am now simply using the difference between the cumulative totals of energy charged & discharged - eChgAll and eDisChgAll - see below. To my mind it should be close to a zero sum game, like measuring total petrol into the tank cf burnt in the engine. If I've put 5000 litres in my car since new then I've definitely burnt all 5000 in the engine since, full to full. 30% doesn't evaporate, and certainly not overnight.

Putting the latest figures in logical event order: 318.4; 301.9; 212.2; 207.9, the cumulative losses between adjacent stages between 10th October and this evening have been: 5.2% (rectification loss); 29.7%; 2.0% (inversion loss).

Is there anything wrong with my interpretation here?

In any case, I really would appreciate seeing other users' figures like those above please?

Many thanks all, Graham