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I have a recently installed 8kw Sunsynk, 2 x Hubble AM2 batteries and 14 x 390W panels.

Early on, I was a little bit concerned by the battery performance. When measuring the change in SOC vs the kwH discharged (from the Solarman app - I used the change in "Total Discharging Energy" to measure this and it was consistent with what I was seeing on the inverter panel), I was only getting an average of about 0.75kwH per 10% discharge (typically running SOC from 100% to 35%) . This implied a total capacity of 7.5kwH instead of the expected 11kwH. My installer, in consultation with Hubble, thought it might be an equalisation issue and charged and discharged both batteries using voltages (amongst other ideas). No joy - my installer agreed that one battery seemed to be underperforming and has returned it to Hubble for analysis.

I have since been running only one battery whilst I wait for Hubble to resolve the issue with the other one. This one battery is discharging at a rate of about 0.47 kwH per 10% SOC change (typically running SOC from about 100% to 25%), implying a total capacity of about 4.7kwH. This is obviously much better, but still only about 86% of "labelled" capacity. Given that I will likely only run the battery down to say 25%, this means that on a 5.5kwh battery, I will only get about 3.6kwh out of it.

 

So, my question is, does this seem reasonable? I understand that there can be measuring issues (on either or both the inverter and Solarman app) and that there will be some loss on conversion from 51V DC battery to 230V AC (although I'm not sure whether the inverter shows the kwH used before or after conversion), but 86% of actual capacity seems quite low to me.

I'd be interested to know what other guys are getting (kwH used per 10% change in SOC), both those with the same setup, and those with different batteries.

 

Thanks

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Posted (edited)

This is my stats from Solarman using the 8kw sunsynk and 4 x US3000 pylontech batteries. Total capacity of 14kWh and running them down to 15% SOC overnight. 

If you look at 24 April I put in 14.3kWh. You can't really take the total discharge as it spans the morning and night and not a continuous discharge amount. 

Screenshot_20210501-120156_SOLARMAN Smart.jpg

Screenshot_20210501-120259_SOLARMAN Smart.jpg

Edited by Achmat
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Thanks Achmat.

Below is a screen I use to measure it. "Total Discharging Energy" and "Total Charging Energy" under Device Data. These fields are cumulative so you need to calculate the difference. So, I have 2 snapshots below, one at 25% SOC and one earlier at 99% SOC.  You'll see total charging energy hasn't changed over this period (there was no charging) but total discharging energy has changed by 3.6kwH. So, 3.6kwH were discharged for a 74% change in SOC.  This is about 0.5kwH per 10% (a bit better than some of my other calcs, but the increments of measurement do affect the calc slightly). 

 

You can still do the calc even if there has been some charging over the period by offsetting the change in charging energy.

 

1953999030_2021-05-01(3).thumb.png.0caa8ab8111be5d1aeadaa941ff29e11.png 

 

2021-05-01-NOOK.thumb.png.66d2664aca71bb4e9664eca1dcbb0af2.png

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Posted (edited)

I've already pushed more than 2MWh through my batteries so it doesn't give enough decimals in the cumulative graphs. 

From 100% to 90% SOC I used 1.4kWh for 10% from a 14kWh pylontech battery bank so its within the expected range. 

Screenshot_20210501-133352_SOLARMAN Smart.jpg

Screenshot_20210501-133422_SOLARMAN Smart.jpg

Screenshot_20210501-132739_SOLARMAN Smart.jpg

Edited by Achmat
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Thanks @Achmat.

Your looks spot on - so on a sample size of 2, your battery performance is looking true to label and mine is not!

Will be interested to hear from others, especially Sunsynk/Hubble combos.

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7 minutes ago, Saul said:

Thanks @Achmat.

Your looks spot on - so on a sample size of 2, your battery performance is looking true to label and mine is not!

Will be interested to hear from others, especially Sunsynk/Hubble combos.

@leshenis the resident sunsynk/Hubble combo installer and could maybe get more stats from a few of his installations.

This is actually a good exercise in comparing different battery setups. 

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6 hours ago, Saul said:

I have a recently installed 8kw Sunsynk, 2 x Hubble AM2 batteries and 14 x 390W panels.

Early on, I was a little bit concerned by the battery performance. When measuring the change in SOC vs the kwH discharged (from the Solarman app - I used the change in "Total Discharging Energy" to measure this and it was consistent with what I was seeing on the inverter panel), I was only getting an average of about 0.75kwH per 10% discharge (typically running SOC from 100% to 35%) . This implied a total capacity of 7.5kwH instead of the expected 11kwH. My installer, in consultation with Hubble, thought it might be an equalisation issue and charged and discharged both batteries using voltages (amongst other ideas). No joy - my installer agreed that one battery seemed to be underperforming and has returned it to Hubble for analysis.

I have since been running only one battery whilst I wait for Hubble to resolve the issue with the other one. This one battery is discharging at a rate of about 0.47 kwH per 10% SOC change (typically running SOC from about 100% to 25%), implying a total capacity of about 4.7kwH. This is obviously much better, but still only about 86% of "labelled" capacity. Given that I will likely only run the battery down to say 25%, this means that on a 5.5kwh battery, I will only get about 3.6kwh out of it.

 

So, my question is, does this seem reasonable? I understand that there can be measuring issues (on either or both the inverter and Solarman app) and that there will be some loss on conversion from 51V DC battery to 230V AC (although I'm not sure whether the inverter shows the kwH used before or after conversion), but 86% of actual capacity seems quite low to me.

I'd be interested to know what other guys are getting (kwH used per 10% change in SOC), both those with the same setup, and those with different batteries.

 

Thanks

Hi Saul. 
 

Are you based in Jhb or Cpt as no units were sent to Jhb for testing. Only 2 in Cpt. So if the batteries have a fault, they will be swapped out with new ones. 
 

Just check on your SOLARMAN app that the Calculation of Electric Energy is set to Based on device data and not Based on Calculation. 

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1 hour ago, Tariq said:

Here is my graph for today, @Achmat, can you tell from the graph, what am I getting. I have two 2.4 kWh Pylontech batteries 

C4292611-3D9F-49E2-8739-417926017E4A.png

You need to click on device and select the inverter. Under parameters you can Al ecstacy SOC, daily battery discharge. 

Select two points, one at 100% SOC and another at 90% SOC. The difference in daily discharge would be the kWh used from 100% to 90%.

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16 minutes ago, Tariq said:

The graphs are not 100 % accurate, did the test again came out to .47 kWh for every 10 % soc

It's still very close to the actual capacity of the battery. Two 2.4kWh batteries should give you a total of 4.8kWh so every 10% used should be about 0.48kWh.

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@leshen I am based in Cape Town. My installer is dealing with Hubble - we returned the battery last week - but their initial thought is that it is the BMS. They said they would swap it out for a new BMS this week and do some tests but can't replace the entire battery as they have no stock. Ideally, if it is faulty, I'd want a complete replacement, but have no idea when they will get stock. Do you think a new BMS is reasonable or would you wait for an entirely new one if it is not too long a wait?

My installer granted me access to the plant via Business Solarman - so it appears as if I can't see or change the Calculation of Energy field. However, I don't think this is an issue because the manual suggests the default is Based on Device and in any event, it is only used to determine how to combine fields for more than a day i.e.  for measurement during the same day, both methods will be the same.

I'd be interested in what you are seeing on your Sunsynk/Hubble installations - as it stands, my remaining healthy battery (not the one I sent in) is underperforming its label capacity by over 10% (whilst @Tariq and @Achmat are seeing performance in line with expectations). I'd obviously like to be able to see if it is my particular battery or in fact the Hubble batteries behave like this in general.

 

@Tariq, I doubt the graphs are 100% accurate, but are fairly close - you can probably remove most of the variation in measurement caused by rounding by doing it over a longer period - e.g. measure SOC from 100% to 60% and dividing by 4.

 

 

 

 

 

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@Saul You could also leave the battery at 100% till after sunset and then start using the battery to 50% over a few hours and see on the inverter display what the discharge value is. Ideally you want this test to have no battery usage at all during the day or morning. 

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49 minutes ago, Saul said:

@leshen I am based in Cape Town. My installer is dealing with Hubble - we returned the battery last week - but their initial thought is that it is the BMS. They said they would swap it out for a new BMS this week and do some tests but can't replace the entire battery as they have no stock. Ideally, if it is faulty, I'd want a complete replacement, but have no idea when they will get stock. Do you think a new BMS is reasonable or would you wait for an entirely new one if it is not too long a wait?

My installer granted me access to the plant via Business Solarman - so it appears as if I can't see or change the Calculation of Energy field. However, I don't think this is an issue because the manual suggests the default is Based on Device and in any event, it is only used to determine how to combine fields for more than a day i.e.  for measurement during the same day, both methods will be the same.

I'd be interested in what you are seeing on your Sunsynk/Hubble installations - as it stands, my remaining healthy battery (not the one I sent in) is underperforming its label capacity by over 10% (whilst @Tariq and @Achmat are seeing performance in line with expectations). I'd obviously like to be able to see if it is my particular battery or in fact the Hubble batteries behave like this in general.

 

@Tariq, I doubt the graphs are 100% accurate, but are fairly close - you can probably remove most of the variation in measurement caused by rounding by doing it over a longer period - e.g. measure SOC from 100% to 60% and dividing by 4.

 

 

 

 

 

It’s highly unlikely that the cells are damaged on a new unit. Hubble is very good at testing and honoring their warranties. So if it’s just a BMS issue then, I would be happy with a BMS replacement. However if any cell is damaged, Hubble will tell you that there is a problem with one or more of the cells and they would give you a new battery. 
 

I haven’t had any issues on any other Sunsynk/Hubble installations. 
 

 

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10 minutes ago, Saul said:

Thanks @leshen.  I'll see what Hubble say this week.

When you say no issues with other installations - does that mean you are seeing 0.55kwH per 10% SOC (per AM2) on these installations ?

We connect a RIOT up to the battery which is way more accurate and we get 0.56kwh per 10%. The AM2 is a 117AH battery. 

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Thanks.

Useful to know - which leads me to conclude that either the Sunsynk/Solarman information is VERY inaccurate (although it seems accurate with the Pylontechs as per @Tariqand @Achmat - perhaps it doesn't communicate with Hubble well?) or that my brand new healthy battery is not so healthy ...

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Two members have previously contacted me about possible battery non/under performance and on both occasions the data set appears to support that my batch of Hubble Am-2 are delivering the required power. On the most recent one I gathered the following information over a period we had a Eskom power failure and sun had set.

While it is a limited time-frame and averages could throw out the measurements, It does appear to correlate.

My Setup is 8Kw Sunsynk connected to a RIOT via CAN and the RIOT is connected to the master of 2 x AM-2 batteries by serial connection. Period 17:34 - 20:11

Solarman App: in inverter data.

17h34 values of 91% SoC, Total Charge 680.80 Total Discharge 624.20

20h11 values of 72% SoC, Total Charge 680.80 Total Discharge 626.50

Delta (626.50 - 624.20) 2.3 kWh

Assumed Power used @19% delta SoC (91%-72%)  ≈ (5.5KW *2)*19% =2.090 KW

ROIT data:

I can extract the status of my combined batteries for the same period from the RIOT , the I and V Data is exported to excel and then manually calculate an instantaneous power per reading and sum to see total expected.

The RIOT reports V and I readings every 5 seconds. If I take I x V (instant power) /60 min /60 Sec x 5 seconds it should give me the power produced in KVA for each 5 sec slot, sum up the 1800 odd entries and should be total power used.

Total sum gives me 2.213 KVA

Solar man App graphs

image.png.f0a428435a3953bfcc67545a0765f965.png

ROIT graph

image.png.bf0cec23ea7dd8d5070416807f5d77bd.png

 

While none of these 3 readings match (Expected 2.09 KW vs Solarman 2.3 KW vs RIOT 2.213 kVA) and the whole power factor question in kAH/kW . It is more likely due to the mismatch of data points between the sources and the SoC was closer to 20% than 19.

At worst it appears my batteries are working better than advertised.

 

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On 2021/05/01 at 11:49 AM, Saul said:

So, my question is, does this seem reasonable?

@Saul Sorry to hear about the issues with capacity. Unfortunately not the first time I've heard it in relation to the AM2s... My original question to @Kill_switch was based on feedback I got from a supplier of the Hubble batteries, who advised that their testing showed a significant shortfall in capacity on the one test unit they were sent by Hubble. I can't verify integrity of the data, except to say that the supplier had no issue with offering the (cheaper) X101 Hubble batteries, so my feeling is that it was a true concern to them. However for every person I've talked to with a low opinion of the brand, there are more people who think the AM2s are unbeatable in quality and specification. 

From the feedback I've gotten talking to people with the batteries and other's who investigated supplying them; this is not a common issue, but definitely not unheard of. Manufacturing defects can and do happen in all industries, so it would be unfair to paint a whole brand in a bad light from a few defective units. However, it was enough of a concern that I personally decided to buy the Pylontechs instead. Pylontech also have returns and defective units (not capacity related that I'm aware of), but they've been available a lot longer and I felt that if there was a major issue we'd know about it by now. (Note they're not installed yet, so I can't share usage data unfortunately... If someone has other information then I'd happily drop them like a hot turd and try a different brand. My loyalty is only to my wallet :P)

Now for your case specifically, "does this seem reasonable"... What follows is only an opinion and you can apply sufficient seasoning thereto: What you're experiencing would be completely unacceptable to me. The capacity of a battery goes down depending on the current draw, so I find it wholly unacceptable that a battery rated for 1C discharge would give even 1% less than its rated capacity when you're discharging at less than 0.3C. The experience reported by Kill_Switch is the least I'd expect from a battery with such a 1C specification: It SHOULD have more than advertised capacity at low discharge rates, or else it WILL deliver less capacity at high discharge rates. 

A big deal (and many sales) has been made in the past because these batteries are 1C-rated as opposed to the other brands that were "Only 0.5C" (Heaven forbid! *clutches pearls and faints*), so if they can't deliver on this then I feel they're being more than a little misleading. At the very least they should show how the battery is de-rated for different current draws, so that anyone can make an informed decision.

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On 2021/05/02 at 9:29 AM, Saul said:

Do you think a new BMS is reasonable

Sorry - I know this is addressed to Leshen directly... And I agree that in principle you only need to replace the faulty part to get a functional system. But the BMS is the Thin Blue Line separating your fancy schmancy lithium batteries from lead-acid anarchy 🤨 

That is to say: If the BMS has been defective then who knows what damage has already been done to the rest of the battery system? Operating on the wrong charge values, or mis-reading voltages or currents could very well have been over or under-charging your cells. There's a 10-Year warranty yes, so if the cycle life is affected long term then you can always do a warranty claim... but you're already struggling to get replacements for NEW batteries, so how confident are you that in 9 years 11 months they'll still have an AM2 with your name on it? 

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