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Author Topic: LuxPower network protocol decoding  (Read 12756 times)
AndyWhittaker
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« Reply #75 on: January 08, 2021, 12:44:34 PM »

Hi Guys,

Quick question, I have two parallel LUX LXP3600 inverters with each inverter having two PylonTech US3000 batteries (i.e. 4 in total).

I charge them every night on Octopus Go to take advantage of the 4 hour cheap rate window. I am thinking of putting an extra pair of US3000s on them (to make 3 on each inverter) but looking at the graphs they are only charging at 1.5kW which might mean I will miss the 4 hour charge window.



If you look at the US3000 spec sheet it says that each battery can take a recommended 37Amps charge rate with a maximum of 74Amps charge rate which @48V works out at ~3.5kW. However my LUX units are only sending 1.5kW to them (~31A).

I would have thought two batteries in parallel would have allowed the inverter to at least double that rate (assuming it's not current limited).

Am I missing something ?
« Last Edit: January 08, 2021, 03:42:49 PM by AndyWhittaker » Logged

Andy Whittaker
Prestbury, UK

4KW Solar PV
HYD6000 Hybrid Inverter
LUX LXP3600ACS x 2 in Parallel
6 x US3000 PylonTech Batteries

Tesla Model 3 Long Range
biohead
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« Reply #76 on: January 10, 2021, 10:29:07 AM »

Where are the batteries stored Andy?

The temperatures over the last month or so in the UK have been low enough for any batteries exposed to it to trigger the reduced charging rates.
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AndyWhittaker
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« Reply #77 on: January 10, 2021, 11:01:38 AM »

Yes I thought it was possible temperature but the battery bank is in the garage which is quite well insulated. However, I would have thought that if it was limiting only due to the temperature, it would get better during the charge.

Additionally, they are behaving like a single battery and not how I would have expected two in parallel to perform.

I have confirmed with Lux that it is the batteries telling the inverter to only charge at the lower rate. I've sent an email to PylonTech but it was too late on Friday.

I'll share what I find.

Andy
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Andy Whittaker
Prestbury, UK

4KW Solar PV
HYD6000 Hybrid Inverter
LUX LXP3600ACS x 2 in Parallel
6 x US3000 PylonTech Batteries

Tesla Model 3 Long Range
biohead
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« Reply #78 on: January 10, 2021, 11:49:49 AM »

In theory, you could deplete the batteries, shut everything down, disconnect them and bring them inside to warm up for quite a few hours.

Then later on tonight, you could put them back in situ turn everything on and started a forced charge straight away. If they charge at full rate, you almost certainly know it's temperature related.


I've ended up temporarily modifying the octolux rules.rb to double the charge required size, which seems to have done the trick exactly.
My garage isn't insulated at all. Great for keeping beer cold, not so great for the batteries. I am looking at some sort of heat mat to see if that would help (like the ones you'd get in a reptile house).

Ref batteries in parallel - I only have US2000 so there may be a difference. But the nominal charge rate of a single US2000 is 1.2kW (or 25A). In reduced temps, that drops to 12.5A. However, I have 2 in parallel and so get a 25A charge currently. If it was warmer, I would get a 50A charge. To me, that looks like your batteries are performing as expected for cold weather. They're just not getting above the threshold to allow more charge.
« Last Edit: January 10, 2021, 11:57:58 AM by biohead » Logged
nowty
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« Reply #79 on: January 10, 2021, 11:54:11 AM »

AndyWhittaker, did you set the two batteries up correctly as master and slave as shown in the Pylontech manual ?

Could it be you have only one set as master and the other is in standalone mode ?

Therefore the master only thinks its a single battery.
« Last Edit: January 10, 2021, 12:34:08 PM by nowty » Logged

12 kW of PV installed and 67 MWh's generated.
Useable home battery storage of 50 kWh's.
Hot water storage of 15 kWh's.
Storage heaters of 15 kWh's.
EV BMW i3 (another 30 kWh's of storage).
6kW Ground source heatpump.
320,000 litres of water harvested from underground river.
biohead
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« Reply #80 on: January 10, 2021, 12:11:21 PM »

I wonder if the Pylontech documentation is causing some issues. For the US2000, the max charge/discharge rate is specified as 50A (and US3000 as 74A) - but I believe our Lux inverters won't even try to go anywhere near to those values. I think they're the absolute maximums.

I believe our inverters go upto 25A/37A maximum per battery. And the cold weather approximately halves those values.
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AndyWhittaker
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« Reply #81 on: January 10, 2021, 01:50:38 PM »

I have two inverters both running in Master/Slave mode. This is working well.

Each inverter has 2 x US3000 batteries. The inverters are receiving from each battery chain the charge current which the Lux inverters are complying with.

Regardless of the temperature (I believe the actual cells are around 20 degrees C), the PylonTechs are not asking for a higher charge current even though they are a pair in parallel - both strings are behaving the same and are even telling the Lux that there is 100AH of capacity available.

I suspect this can only be answered by PylonTech... 😐
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Andy Whittaker
Prestbury, UK

4KW Solar PV
HYD6000 Hybrid Inverter
LUX LXP3600ACS x 2 in Parallel
6 x US3000 PylonTech Batteries

Tesla Model 3 Long Range
nowty
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« Reply #82 on: January 10, 2021, 02:15:55 PM »

I have two inverters both running in Master/Slave mode. This is working well.

Each inverter has 2 x US3000 batteries. The inverters are receiving from each battery chain the charge current which the Lux inverters are complying with.

Regardless of the temperature (I believe the actual cells are around 20 degrees C), the PylonTechs are not asking for a higher charge current even though they are a pair in parallel - both strings are behaving the same and are even telling the Lux that there is 100AH of capacity available.

I suspect this can only be answered by PylonTech... 😐

My question to you was about the batteries, not the inverters.

If you have multiple batteries connected to an inverter, one battery needs to be the master and the other batteries (only one in your case) are slaves. If they were not set up correctly the master battery may think its the only battery in the stack and reports that to the inverter, hence only half the charge rate.

Page 15 and 16 of,   https://autosolar.es/pdf/US3000-Product-Manual-18BQSV0801.pdf


EDIT - I have just noticed your comment on your inverter is indicating 100AH. That would be the case with 2 x US2000 batteries but should be around 150AH for 2 x US3000 batteries.

Does the system still discharge 3kW per inverter ?
« Last Edit: January 10, 2021, 04:24:11 PM by nowty » Logged

12 kW of PV installed and 67 MWh's generated.
Useable home battery storage of 50 kWh's.
Hot water storage of 15 kWh's.
Storage heaters of 15 kWh's.
EV BMW i3 (another 30 kWh's of storage).
6kW Ground source heatpump.
320,000 litres of water harvested from underground river.
AndyWhittaker
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« Reply #83 on: January 10, 2021, 05:17:49 PM »

When I turn on the heaters of my electric car while it's still plugged in, its consumption rises to 7,892 watts and the Lux inverters start to discharge at 6,668 watts (and obviously the SOC drops like a stone). At the same time the grid import rises to 1,492 watts to make up the difference.

This all seems to work as expected.

Andy
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Andy Whittaker
Prestbury, UK

4KW Solar PV
HYD6000 Hybrid Inverter
LUX LXP3600ACS x 2 in Parallel
6 x US3000 PylonTech Batteries

Tesla Model 3 Long Range
AndyWhittaker
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« Reply #84 on: January 11, 2021, 03:10:08 PM »

I had a good (email) chat with Jeff from PylonTech this morning. Basically my batteries are working as designed.

Normally the batteries charge at 0.5C. In this condition, the charge current of two US3000 will be 0.5 x 2 x 37=37 A.

When the temperature is below 15 ℃ or higher than 45 ℃ or the SOC of the battery is over 90%, the battery will go into the self-protection mode, which means the C-rate of the battery will decrease to 0.2C. At this time, the charge current of the two paralleled batteries will be 0.2 x 2 x 37= 29.4 A.

I asked what would happen when I add a third US3000 in parallel and he said the batteries will react like the formula above but with x 3 rather than x 2 ->

0.5 x 3 x 37 = 55.5 A which @48V would mean I will see a charge power of 2,664 watts.

My extra set will be arriving soon so I'll report back.
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Andy Whittaker
Prestbury, UK

4KW Solar PV
HYD6000 Hybrid Inverter
LUX LXP3600ACS x 2 in Parallel
6 x US3000 PylonTech Batteries

Tesla Model 3 Long Range
AndyWhittaker
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« Reply #85 on: January 12, 2021, 04:56:46 PM »

My extra pair of US3000 batteries arrived today and I have successfully installed them into my (very heavy) battery-rack:



One advantage of having parallel inverters was that I was able to add the extra batteries online and not have to isolate the UPS supply to my computers and central heating.

The inverters now report a connected battery capacity of 150AH each.



As a side, I have also asked PylonTech what they recommend for an acceptable Charge and Discharge SOC. Currently I charge to 100% during the evening on cheap rate and discharge to a minimum of 20% during the day. When I hear back I'll update this post.

My battery area could now do with a tidy-up!

Andy
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Andy Whittaker
Prestbury, UK

4KW Solar PV
HYD6000 Hybrid Inverter
LUX LXP3600ACS x 2 in Parallel
6 x US3000 PylonTech Batteries

Tesla Model 3 Long Range
jmac
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« Reply #86 on: January 17, 2021, 04:41:49 PM »

I've started a discussion on the next step for charging strategies here: https://www.navitron.org.uk/forum/index.php/topic,32470.0.html
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AndyWhittaker
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« Reply #87 on: January 17, 2021, 04:57:17 PM »

Now that the new set of batteries having been running for a few days, here are my comparative charge current differences:

First here is the original pair of US3000s charging:



This is per inverter and shows that originally they were charging at 1,457W giving a system charge rate of 2,914W.



With 3 x US3000s, the charge rate increased to 3,420W for each inverter or 6,840W for the pair (much better!)

I installed the new US3000s into the first of the parallel chain as per PylonTech's instructions but nothing else. So by fitting an extra US3000, this more than doubled the charge current with a third extra capacity which means I am able to charge to 100% within my 4 hour cheap rate window.

I can only guess that the new US3000s have a modified firmware allowing a higher charge current or.... don't know!

Andy
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Andy Whittaker
Prestbury, UK

4KW Solar PV
HYD6000 Hybrid Inverter
LUX LXP3600ACS x 2 in Parallel
6 x US3000 PylonTech Batteries

Tesla Model 3 Long Range
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