Uhome LFP 2400 Voltage Falling Under No Load Conditions

propnut

GAJ59 said:

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

Oh my friend, welcome to the club. Take a look at my posts starting on this page from 17th Jan onwards.

https://forums.moneysavingexpert.com/discussion/6113817/lux-ac-battery-controller/p128

GAJ59

Thanks propnut - yes I'd already found your link to the other thread - I thought I was buying some energy saving technology, but instead I've invested in a new hobby!

I don't have access to the BMS (only the LuxPower app) - how do I go about getting that?

propnut

GAJ59 said:

Thanks propnut - yes I'd already found your link to the other thread - I thought I was buying some energy saving technology, but instead I've invested in a new hobby!

I don't have access to the BMS (only the LuxPower app) - how do I go about getting that?

Yes bloody irritating isn't it. 

 For the batteries you download the Uhome app, create and account and then follow the video instructions I posted which I think was in this thread but it could have been in the other. BUT if you don't get the wifi for the battery showing you may need to hold the reset button for 7secs. You need to register yourself an account first within the app. 

The batteries can only be registered once so check with you installer as to whether or not they already did this. Although having said this mine were clearly already bound to something and I still managed to open my own account and register them.

GAJ59

Thank you, I'll give that a try.

I've been graphing some of my data and came up with this:

This charts the cumulative missing kWh by week since I have had the installation. Looks linear n'est pas? The trendline gradient is 5.55 kWh/week which would equate to 33W average continuous consumption. I think podnut measured his inverter at 30W, as opposed to the claimed 10W in the spec, so I wonder if this chart is reflecting the same issue?

This gives me some comfort. Since installation I've averaged 19.1 kWh charge per week, so 5.5 kWh is a big chunk of that. As the daylight/sunshine hours pick up I expect to be fully charging the battery almost every day - if I can use all that then the 5.5 kWh/week overhead becomes less of an issue.

GAJ59

Sorry, previous image was refused!

GAJ59

Now I've remembered how to do it! I'm new here

propnut

GAJ59 said:

Thank you, I'll give that a try.

I've been graphing some of my data and came up with this:

This charts the cumulative missing kWh by week since I have had the installation. Looks linear n'est pas? The trendline gradient is 5.55 kWh/week which would equate to 33W average continuous consumption. I think podnut measured his inverter at 30W, as opposed to the claimed 10W in the spec, so I wonder if this chart is reflecting the same issue?

This gives me some comfort. Since installation I've averaged 19.1 kWh charge per week, so 5.5 kWh is a big chunk of that. As the daylight/sunshine hours pick up I expect to be fully charging the battery almost every day - if I can use all that then the 5.5 kWh/week overhead becomes less of an issue.

Yep, it sucks right and getting stone silence from the agent and the manufacturer sucks even more. You think, ok I am going to get all this free solar only to find your box of tricks is wasting it and actually costing you more money as a result???? Now you see why I switch mine off every night. Once my smart 125amp isolator comes I won't need to but for now off it goes each night. Why waste energy ?

Thing is you can't just turn off the batteries as the CAN bus connection from the inverter initiates auto restart after a few minutes so you have to turn off the AC to the inverter first and then power off the master battery.

1961Nick

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

I meter the charge/discharge of my sofar inverter & the actual round trip loss around 20%.

(The figure according to the inverter is only 12.2%)

1961Nick

During the cold spell I noticed some unusual behaviour from my pylontechs as they approached the minimum DOD & after they'd gone into standby.

While they were running with a reasonable load they generated enough heat to operate normally. Later in the evening as the ambient temperature dropped & the load reduced, the pack temperature started to fall resulting in the SOC reducing more quickly than would be expected. 

On the occasions that the pack went into standby while discharging at a higher rate, the fall in temperature would happen after they'd entered standby resulting in the SOC continuing to fall below the minimum set DOD.

I also suspect that the amount of battery 'standby' balancing increased on very cold days possibly knocking another 1% off the DOD.

SproutsMr

Just wanted to say thank you to the members of this forum for their help. Specific call out to @@propnut.  Following your advice, I contacted the distributor directly, and they contacted and worked with my installer to correct my issues. You guys were correct.. the biggest issue I had was that it was determined that 2 of my 3 uhome batteries were in deep sleep / hibernation and were not online.  Once this was corrected, all seems to be working fine now. 

Thanks again!