See https://chemistry.stackexchange.com/questions/29179/how-come-diluting-a-cell-decreases-the-voltage

My assertion the voltage in a cell is decreased by diluting the cell is not necessarily true.
According to the Nernst Equation:

. . .
Ecell=E0−RTnFln(Q)

Where Q is the reaction quotient relating [metal ion formed by oxidation][metal ion reduced]

Q can be increased by: increasing the concentration of the metal ion formed by oxidation, or by decreasing the concentration of the metal ion that is reduced. By increasing the value of Q, the magnitude of the term −RTnFln(Q) is increased. This means that a larger number is subtracted from the E0 of the cell, and that the cell voltage decreases.

Q can be decreased by: decreasing the concentration of the metal ion formed by oxidation, or by increasing the concentration of the metal ion that is reduced. By decreasing the value of Q to a fraction, the value of the term −RTnFln(Q) is made positive. This means that this term is added to the E0 of the cell, and that the cell voltage increases.

This is consistent with the Le Châtelier’s Theorem. Essentially, increasing the relative concentration of your reactants drives the reaction forward (higher ΔV), and increasing the relative concentration of your products drives the reaction backwards (lower ΔV).
https://chemistry.stackexchange.com/questions/29179/how-come-diluting-a-cell-decreases-the-voltage

Subject: Re: Dewalt Planer D26500K
Date: Sat, 28 Jul 2018 15:14:33 +0100
From: roger
To: Phagura, Amrit

Hi

Thanks for the chat some month or so ago.

Here are some issues I have that you may be able to respond to.

Blade setup. It would be nice if they are set up when they leave the factory, or do they ’settle’ and therefore need doing before retail and then again have to be done by the user. I found it cut slightly uneven even when on zero and even after my adjustment. I laid a piece of wood across the foot to check the height and see if would move and although it didn’t move it still cut on zero. I will try and set it level on 0.1mm and see if that removes the cut on zero.

No Allen key and no indication of size so I have to fiddle around to find a fit which may not be the best and damage the hexagonal socket shape. It seems odd that one wasn’t supplied. Hardly a cost issue, so why isn’t it provided?

The Plastic foot bob gets in the way and should have an option to click it horizontal so as not to use, or removable, like the height adjuster. I’m levelling long piece before I use a No7 hand plane. As I do not want to start from the ends the foot is in the way and I have to move forward before I start to cut which is annoying.

Thanks

Roger Lovejoy

IUI Charging This is a recently developed charging profile used for fast charging standard flooded lead acid batteries from particular manufacturers. It is not suitable for all lead acid batteries. Initially the battery is charged at a constant (I) rate until the cell voltage reaches a preset value - normally a voltage near to that at which gassing occurs. This first part of the charging cycle is known as the bulk charge phase. When the preset voltage has been reached, the charger switches into the constant voltage (U) phase and the current drawn by the battery will gradually drop until it reaches another preset level. This second part of the cycle completes the normal charging of the battery at a slowly diminishing rate. Finally the charger switches again into the constant current mode (I) and the voltage continues to rise up to a new higher preset limit when the charger is switched off. This last phase is used to equalise the charge on the individual cells in the battery to maximise battery life. http://www.mpoweruk.com/chargers.htm

2018 Feb 28
Have removed Stecca as unlikely to use in current situation. Rewired Stecca load block to load block for Victron, removing the wire for the router in the Victron to add the defunct Stecca block which only feeds the 12v amp; which doesn’t seen to work. Will try later when V=12. Else try again with separate battery or try and check out amp.Amp could do with checking after many years of being ignored.

Feb 12th
Used for a few hours to run the amp and the battery went down to 12.26. That’s Batt3 which I thought was well charged - ti took a while to charge up on the 13th but doesn’t appear to take much load when checking how the voltage drops when it is turned on. Will try again !

It now appears that
a) the batteries were not properly charged with n SG of1.25
b) Relying on the Victron indicating float as battery was fully charged when switching from absorption @ 14.5v was misleading.
c) Repeatedly doing as in 2 above over 3 years seriously undermined the batteries capacity by 90%

November 10th, 2014
I arose at 4am on the morning of 10th Nov to read the Load Ah and the Steca records 5Ah. It is now nearly 10am and the reading is 6Ah. I suppose I can relay on the fact that the phantom use it consistent. Some 6Ah in 44hour (6000mA divided by 44 = 136mA) some 11 times the specified ‘own consumption’ of 12.5mA.

It begs the question; What is it measuring?

Clearly it is not measuring the load as I would expect.
Why would it measure it’s own consumption?
What happens to the waste power when the current is too much for the battery state? Is it measuring that?

It seems that although it is interesting, having some monitor, these questions make it a inaccurate in terms of power measurement.

I assume the Ah into the battery actually pass through the battery terminals. I say this as the Charge Ah is the same as the Load Ah, although I noticed during charging yesterday they did not keep pace and the Load Ah only caught up over night. I wonder if I disconnect the battery from the Steca will it still show the Load Ah, but then obviously not as it will have no power, but I could try it in the day.???

So is this reading an un-understandable one or is it me that is failing to understand how the Steca works?

If you think this unit is faulty please send me another and I will install it and return the current one if that is the case. Of course as you didn’t sell me the unit directly maybe you could authorise Wind and Sun to send me one.

I wonder if you actually test the unit as I do? i.e. without any load for a significant time and if you do could you please sent me your data. Better still could you please send me the data anyway

All the best

Roger Lovejoy

Connecting the panel to the battery

• Use 20 amp cable (2.5mm) for up to 6m length or 30 amp(4mm) for up to 16 metres.
• To ensure minimal sparking cover panel with blanket when connecting.
• The junction box on the Vikram 100 has two clips, one each to the left and right. Once these are flipped the cover can be removed.

Procedure

• Pass wires through the grommets. Either one through each of the two located at the bottom of the junction box or both through one if the diameter of the cable permits.
• Crimp or solder 6mm round hole terminals or spade terminals to the ends of the cables once inserted through the grommets. You may like to tie a loop in each cable to ensure it cannot be pulled back through the grommet.
• Connect one wire to battery and then that wire to the panel.
• Then connect the other wire to the battery and then to the terminal. At this point if the panel is well covered from sunlight there is unlikely to be any sparking.
• Ensure a tight connection on the terminals and then tighten the grommet(s) to weather proof
• Once you have replaced the junction box lid uncover the panel and direct towards sun.

05/01/15 @ 19:27
Brain Dead second email from REC

Dear Mr. Lovejoy,

on the picture below you can see the crimping marks. Our frame is crimped and you can find the marks on all 4 corners.

Regarding the corner gap – could you please send us the pictures, how the corner gap looks like?

Mit freundlichen Grüßen / best regards

Anton Babjak

My Reply

Dear Anton Babjak

It seems that you are not reading my email very well.
Maybe someone forwarded my email to you and you can’t understand that.

1. You sent me a picture of the crimped corners that I sent you? It’s a picture that I took??
The anodised frame is damaged.

2. I have not said there is a ‘corner gap’
Please read the email and look at the pictures. The gap is between the frame and the glass.

????

Roger
Copied to Andrea.Helbich@recgroup.com and
Kelvin at Wind and Sun

04/01/15 @ 14:42
My first response from REC

Dear Mr Lovejoy,
I’m sorry I haven’t received any request from you. Please send your request again.

Mit freundlichen Grüßen / best regards,
Andrea Helbich
Andrea Helbich | Office Assistant | REC Solar EMEA GmbH
Leopoldstr. 175 | 80804 München | Germany
Phone +49 89 44 23 85 923 | Fax +49 89 44 23 85 999
www.recgroup.com

My Reply to Andrea Helbich

Dear Andrea Helbich

Thank you for your reply. I am forwarding the email sent on 9th Dec 2014.

I had originally sent emails to post@recgroup.com, sales@recgroup.com, ir@recgroup.com and then found your website form luckily.

My concern is that I bought 4 REC 250PE panels from Wind and Sun (UK) early November 2014, and as I was installing them noticed that the corners were damaged. They looked as though they had been used before.

I contacted my vendor who then checked their stock; here is their reply:

Hi Roger,

I can assure you that these marks must be made during the manufacture of the solar panels as they all have them. These panels are sold with full manufacturers warranty.

Are you happy with that answer or would you like me to do something else?

Regards,

Kelvin

It was after this that I tried to contact REC

Since then I have noticed that the glass module is embedded into the aluminium frame but there is a gap between the frame and the glass. The gap is some 5mm deep and collects water which upon freezing expands. This will inevitably lead to distortion and further widening of the gap, effecting it’s longevity and performance.

I had thought of buying alternative panels but the vendor said that although there was only a 10 year guarantee as opposed to the 12 year elsewhere, you are a good company and they have had no problem with you.

I am now wondering if I have made a serious mistake. Of course since trying to contact you for some two monhs I have noted that your company is in the process of selling to China and sadly one reason I bought form you is that you are a European company. I also note the panels are assembled in Singapore.

So you can see I am not a very happy bunny, although the panels, well the two I have installed, seem to be producing, when the sun shines.

What I would like are panels that don’t have gaps that let water in, don’t have damaged corners and that are made in Europe. Can you help me resolve these problems?

Here are some images to show

a) the damaged corners
Image displayed in main post above

and
b) the gap
Images displayed in main post above

This email is copied to Wind and Sun

Please visit https://calstock.org.uk/elf.php/2001/01/01/rec-250w-panels for a chronological copy of communications regarding this.

Yours sincerely

Roger Lovejoy

29/11/14 @ 19:03
Just refashioned installation. Have two panels above caravan with proprietary cable to terminal block and 70A cable to Victron. 70 amp cable almost too big. Will run two in parallel once I have prop. connectors : can run two in series when overcast and late evening:

Made serious cropping of hawthorn to the south, yesterday 28th

Sun 30th One panel in parallel with old panels feeding old battery no.2. SoC on connect was 3%, at sunset 12%; 3Ah input. Current increased from 2.4A to 6.8A, only 4.4A from REC

31/12/14 @ 02:07
On 9th Dec I sent a second email to REC saying I hadn’t heard from them, now some 4 weeks later I will consider a different approach. About to send third email about crimping and adding not water tight between glass and aluminium frame

Reply from Wind and Sun

Hi Roger,
13/11/14 @ 22:49
I can assure you that these marks must be made during the manufacture of the solar panels as they all have them. These panels are sold with full manufacturers warranty.

Are you happy with that answer or would you like me to do something else.

Regards,

Kelvin

27/28 Dec 2017
During the evening of 27th power went off probably due to percentage charge going below ???. The charge had been at 43% so I thought it would be unlikely to have dropped to 30% which I think is the cut off level. When I went to check the level it was at zero and 11.6v.

Thus morning, the 28th, luckily there was a bit of sun and the percentage crept up to 6% after an hour or so and then jumped to 35%

13/11/14 @ 10:14
Thank you for your prompt reply although it has not answered my queries, rather, it has provoked more thought and questions. I am not sure if part of the problem is language so I will take your responses one at a time.

First Sentence : ‘the reason for the low consumption at the load connection of the charge controller are the components.‘

You are saying there is a consumption but regard it as low and attribute it to ‘the components’

i) To qualify something as low there has to be a corresponding high and the only other figure I have, that you provide, is an internal ‘own consumption’ of 12.5mA. Clearly the consumption I am reading can only be qualified as high, by some 1000%.

ii) You say that the usage is due to ‘the components’; however how do you relate this ‘low consumption’ of some 3Ah a day to the specifications that ‘the components’ or self consumption is 12.5mAH (0.3Ah)

I cannot see why, if the rated self consumption is 0.3Ah per day I could be reading 3Ah per day. Clearly the screen output is either incorrect or the unit is using 3Ah per day. Either possibility is unacceptable.

Second Sentence : If you load this connection you will see that in reality there are no consumption.‘

I find this statement bizarre!

Presumably you mean connect a load to the Load terminals of the Steca and that somehow now I will not see any consumption.

So if no load is connected I will see a consumption, albeit questionable as to whether it is real or not, but if I do connect a load I will not see any consumption.

Maybe you mean I will not see the unreal consumption, only the real consumption, but how would I know what is real and what is not. The unit clearly shows some consumption.

Third Sentence : You can also see this unreal consumption at the display of the charge controller because this value won’t be measured it would be calculated.‘

i) Why does the fact that it is calculated and not measured mean that I can see an unreal consumption.

ii) Why would anyone want to see an unreal consumption?

ii) Why and how does the unit calculate a value from something that doesn’t exist?

All the best

Roger Lovejoy

P.S. For your information the ‘usage’ is consistent and after 4 days the reading is 12Ah

Email to Steca: November 10th, 2014

I arose at 4am on the morning of 10th Nov to read the Load Ah and the Steca records 5Ah. It is now nearly 10am and the reading is 6Ah. I suppose I can relay on the fact that the phantom use it consistent. Some 6Ah in 44hour (6000mA divided by 44 = 136mA) some 11 times the specified ‘own consumption’ of 12.5mA.

It begs the question; What is it measuring?

Clearly it is not measuring the load as I would expect.
Why would it measure it’s own consumption?
What happens to the waste power when the current is too much for the battery state? Is it measuring that?

It seems that although it is interesting, having some monitor, these questions make it a inaccurate in terms of power measurement.

I assume the Ah into the battery actually pass through the battery terminals. I say this as the Charge Ah is the same as the Load Ah, although I noticed during charging yesterday they did not keep pace and the Load Ah only caught up over night. I wonder if I disconnect the battery from the Stecca will it still show the Load Ah, but then obviously not as it will have no power, but I could try it in the day.???

So is this reading an un-understandable one or is it me that is failing to understand how the Steca works?

If you think this unit is faulty please send me another and I will install it and return the current one if that is the case. Of course as you didn’t sell me the unit directly maybe you could authorise Wind and Sun to send me one.

I wonder if you actually test the unit as I do? i.e. without any load for a significant time and if you do could you please sent me your data. Better still could you please send me the data anyway

All the best

Roger Lovejoy

12/11/14 @ 09:57
[b]Email Reply from Stecca[/b]

Dear Mr. Lovejoy,

the reason for the low consumption at the load connection of the charge controller are the components. If you load this connection you will see that in reality there are no consumption. You can also see this unreal consumption at the display of the charge controller because this value won’t be measured it would be calculated.

Best regards / Mit freundlichen Grüßen

i.A. Carmen Hörberg

Customer Support
Solar Electronics Division

Steca Elektronik GmbH
Mammostraße 1
87700 Memmingen
Germany

After Mathias at Victron said I could disable temperature compensation and then after discovering the screen cropping was hiding the control, have disabled. So next time there is enough sun to switch to absorption level will check. All fine

Set cut off voltage to 12.36 and the load was disconnected as soon as it dropped to 12.35 :)

Making sense of charging algorithms

Original Post 05/07/16 @ 08:34
Reading from the manual it makes some sense.

1. If the battery voltage is below 13.2v for more than 1 minute a three part charge cycle starts, called bulk charging, where the maximum current the source can provide is fed to the battery.
2. The second stage, absorption charge, is reached when the voltage reached 14.4v and voltage limiting occurs so the amperage will decrease as the battery charges.
3. The third and final stage, the float charge, initiates when a predefined charge current is reached under the absorption charging stage. This voltage is set at 13.8

The only problem with the above is that the predetermined current set in the absorption stage may be too high or low for the capacity of the battery. In the a the case of a small capacity battery this could lead to over charging of the battery; and in the case of larger capacity will delay a full charge and . . . Luckily all voltage and current set points are programmable, though I’ve yet to manage that.

There is one other problem in that Victron also have a manual that states the absorption charge has a time setting. I have yet to assess whether this is just a safety issue as otherwise it would or may override the above algorithm.

Output Voltages and Monitoring

Following from my pressure on the load terminals, last comment, today although the unit has gone from quick flashing to slow flashing of the yellow LED my computer has not cut off. This is a first as when charging at such rates the voltage rises above 14.4 which is the cut off point for my computer. In fact this is a sore point as it means I have not been able to use the computer since inception of the Victron whilst the batteries are being charged.

However this seems to be a change in the function of the computer as the Load Voltage is 14.5.It may not work if I switch on and off which I am about to do. Did and wouldn’t switch on. No the clouds are out and load voltage is below 13.6.

General Monitoring
Clearly I am finding many problems with these Victron 75|15 units and I think this is because I am doing an uncommon degree of monitoring.

Usually I image these units are placed near the battery, out of view. Mine s installed above the seat under which batteries are stored in a 6′ 6″ x 16′ caravan. The unit is directly in front of me all day I’m working in the office some 4 feet away. If I come into the caravan it is 2 feet left of the door and six feet away so I constantly update my knowledge of how it’s doing. Add to that have a voltmeter next to it and check the voltages multiple times when there is an anomaly.

The way I run my computer is also unusual in that it is connected directly to the Load output via a block and has no internal battery. This means the Load output must be between the acceptable range of the computer’s internal power sensor, which is 11.6 to 14.4. If I was using an intermediary power unit that would convert a range of voltages (11 to 15) to 12v I may well avoid some of the problems I have. However that I have these problems is a sign that the Victron is not working as described. It has a variable output that does not accurately reflect the battery voltage and the charge voltage is often higher than that described by the manual.

March 25th Three batteries connected to Victron
Original post: 15/04/17 @ 17:09

https://calstock.org.uk/elf.php/2001/01/01/rolls-batteries?disp=single&title=rolls-batteries&more=1&c=1&tb=1&pb=1&redir=no&c_paged=16#commentsMarch 25th: Three batteries connected to Victron

https://calstock.org.uk/elf.php/2001/01/01/rolls-batteries?disp=single&title=rolls-batteries&more=1&c=1&tb=1&pb=1&redir=no&c_paged=16#comments

Output Voltages and Monitoring
Original Post :: 30/01/15 @ 11:16
Following from my pressure on the load terminals, last comment, today although the unit has gone from quick flashing to slow flashing of the yellow LED my computer has not cut off. This is a first as when charging at such rates the voltage rises above 14.4 which is the cut off point for my computer. In fact this is a sore point as it means I have not been able to use the computer since inception of the Victron whilst the batteries are being charged.

However this seems to be a change in the function of the computer as the Load Voltage is 14.5.It may not work if I switch on and off which I am about to do. Did and wouldn’t switch on. No the clouds are out and load voltage is below 13.6.

General Monitoring
Clearly I am finding many problems with these Victron 75|15 units and I think this is because I am doing an uncommon degree of monitoring.

Usually I image these units are placed near the battery, out of view. Mine s installed above the seat under which batteries are stored in a 6′ 6″ x 16′ caravan. The unit is directly in front of me all day I’m working in the office some 4 feet away. If I come into the caravan it is 2 feet left of the door and six feet away so I constantly update my knowledge of how it’s doing. Add to that have a voltmeter next to it and check the voltages multiple times when there is an anomaly.

The way I run my computer is also unusual in that it is connected directly to the Load output via a block and has no internal battery. This means the Load output must be between the acceptable range of the computer’s internal power sensor, which is 11.6 to 14.4. If I was using an intermediary power unit that would convert a range of voltages (11 to 15) to 12v I may well avoid some of the problems I have. However that I have these problems is a sign that the Victron is not working as described. It has a variable output that does not accurately reflect the battery voltage and the charge voltage is often higher than that described by the manual.