MPPT query

[Tony1]

10 hours ago, nicknorman said:

 

I think I spot a basic misconception. When you have 2 or more Valence batteries connected in parallel (ie a 12v system) then by basic physics there is no need to contemplate balancing between the batteries, this happens "automatically" because the terminal voltage of each battery connected in parallel must be identical (as you have found out!). Provided each battery's cells are balanced within themselves, all is fine and dandy.

Balancing between batteries is only necessary when the batteries are connected in series, eg a 24 or 48v system. For the same reason that cells in series within a battery have to be balanced.

 

Guilty as charged your honour. 

Things is, I've never dared to contemplate the idea of setting up a 24v system, so that sort of balancing wasn't even on my radar. As is sadly all too clear to our readers, I have only the most ephemeral grip on the workings of 12v systems, so I'm happy to remain ignorant of the wizardy of higher voltages.

My (flimsy) defence for this misconception was that I watched couple of youtube videos I saw a while back (the perils of youtube video lessons....).

They talked about trying to arrange the cabling between the battery terminals so that it was of even length, in order to avoid the risk that one or more batteries might be consistently subjected to more charging/voltage/hassle/something else electrical. 

I then saw comments that balancing between batteries was 'a thing'.

That is where the accused made his fatal mistake.

I assumed that the battery balancing must be done in order to counteract some kind of gradual difference that would arise between batteries because of the physical setup/cabling/something else electrical. 

 

I honestly dont know why more people havent set up as marine electricians. There must be thousands of people like me who have a very limited undertstanding of the principles involved, and who would pay a reasonable fee to have someone safer and more knowledgeable sort these things out.  

As it is is, there are very few of them, you have to wait weeks to see one, and many don't like touching lithium batteries. 

 

 

[MtB]

4 minutes ago, Tony1 said:

They talked about trying to arrange the cabling between the battery terminals so that it was of even length, in order to avoid the risk that one or more batteries might be consistently subjected to more charging/voltage/hassle/something else electrical. 

I then saw comments that balancing between batteries was 'a thing'.

That is where the accused made his fatal mistake.

 

Not only your mistake, but theirs too I assert. 

 

Provided one's battery wires are fat enough (technical term), if the lengths don't match or you used the 'wrong' pattern to connect them up, while you draw 100ah out of one battery you might only be drawing 99.98ah out of each of the others, so in practice it doesn't matter a toot. Its something people focus on as its an easy concept to grasp and waffle on about on forums and in pubs convincingly, especially when they barely understand Ohm's Law. 

 

 

10 minutes ago, Tony1 said:

 

I honestly dont know why more people havent set up as marine electricians.

 

Once you've had a look at the electrical installations in a few other boats, you'll realise exactly why so few people claim to be marine electricians. Bird's nest installations littered with badly crimped high-resistance terminations, where the wires will happily fall out while you're rummaging to find out where each one goes, for example. Also on a strange installation you'll have no idea if it is well designed or a complete basket case, and all the time the boater is interrupting you with stupid questions while you try to figure out what is going on...

 

Time for COFFEE!!

[Tony Brooks]

15 minutes ago, Tony1 said:

honestly dont know why more people havent set up as marine electricians. There must be thousands of people like me who have a very limited undertstanding of the principles involved, and who would pay a reasonable fee to have someone safer and more knowledgeable sort these things out.  

 

I think the clue is in "reasonable" fee. I have been out to help a number of boats since I put my website up and in far too many cases a fair time is needed to work out how the troublesome system has been wired and so on. That is before you start fault finding. It may look as if I was doing very little apart from making notes and drawings. After that you rectify the problem in a few minutes. Add traveling time to the total tome and the customer all too often does not consider the fee charged as "reasonable". In my case I never charged so the customers were happy.

 

Also Lithium technologies come in variety and it takes time to study and get experience of them. I doubt there are more than a handful of practitioners who feel they fully understand them. Personally I would not do anything with Lithium technology for a customer because I now I don't know enough about them - but gradually learning from several members here.

[peterboat]

20 minutes ago, Tony1 said:

 

Guilty as charged your honour. 

Things is, I've never dared to contemplate the idea of setting up a 24v system, so that sort of balancing wasn't even on my radar. As is sadly all too clear to our readers, I have only the most ephemeral grip on the workings of 12v systems, so I'm happy to remain ignorant of the wizardy of higher voltages.

My (flimsy) defence for this misconception was that I watched couple of youtube videos I saw a while back (the perils of youtube video lessons....).

They talked about trying to arrange the cabling between the battery terminals so that it was of even length, in order to avoid the risk that one or more batteries might be consistently subjected to more charging/voltage/hassle/something else electrical. 

I then saw comments that balancing between batteries was 'a thing'.

That is where the accused made his fatal mistake.

I assumed that the battery balancing must be done in order to counteract some kind of gradual difference that would arise between batteries because of the physical setup/cabling/something else electrical. 

 

I honestly dont know why more people havent set up as marine electricians. There must be thousands of people like me who have a very limited undertstanding of the principles involved, and who would pay a reasonable fee to have someone safer and more knowledgeable sort these things out.  

As it is is, there are very few of them, you have to wait weeks to see one, and many don't like touching lithium batteries. 

 

 

Tony I run a 24 and a 48 volts system from these batteries so does JohnV from tother side the batteries remain balanced. My Truck works hard much harder than the boat batteries and has had 3 years of charging discharging without issues, when Wayne who repairs these gave it a once over the other year he remarked how well balanced it was.

Check your wiring on your lead to make sure its correct and I am sure it only runs on windows pro?

[MtB]

9 minutes ago, Tony Brooks said:

That is before you start fault finding. It may look as if I was doing very little apart from making notes and drawings. After that you rectify the problem in a few minutes. Add traveling time to the total tome and the customer all too often does not consider the fee charged as "reasonable".

 

Ah yes. The "£100? All you did was tighten that screw!" syndrome. 

 

Breakdown of bill:

 

Tighten screw: £1

Working out that a screw needs tightening, and which one it is: £99

 

 

 

 

Edited March 10, 2022 by MtB
Finesse a point.

[Tony1]

4 minutes ago, peterboat said:

Tony I run a 24 and a 48 volts system from these batteries so does JohnV from tother side the batteries remain balanced. My Truck works hard much harder than the boat batteries and has had 3 years of charging discharging without issues, when Wayne who repairs these gave it a once over the other year he remarked how well balanced it was.

Check your wiring on your lead to make sure its correct and I am sure it only runs on windows pro?

 

Thanks Peter, I finally got the software running last night by opening it as administrator- that was the big snag. 

 

Within each battery, all the cells were within 2mv of each other, which I'm assuming is pretty well balanced, despite not being treated very well by me! 

I have to say that for the valences- they seem very well made and very resilient to abuse.

There's a reason all those DIY solar fanatics bought them up over the last few years, and they still fetch good prices used.

 

[Tony Brooks]

Just now, MtB said:

 

Ah yes. The "£100? All you did was tighten that screw!" syndrome. 

 

Breakdown of bill:

 

Tighten screw: £1

Working out which screw to tighten: £99

 

 

 

That is so true, especially when it is on the main negative bus bar!

[peterboat]

12 hours ago, Slow and Steady said:

 

Do you mean windows pro version? It's just the same with all the cacky consumer stuff cut out. No need to even pay for it, Microsoft don't care, they just want the world to use windows.

It won't run on windows 7 or 10 I have tried it! So something must be different 

1 minute ago, Tony1 said:

 

Thanks Peter, I finally got the software running last night by opening it as administrator- that was the big snag. 

 

Within each battery, all the cells were within 2mv of each other, which I'm assuming is pretty well balanced, despite not being treated very well by me! 

I have to say that for the valences- they seem very well made and very resilient to abuse.

There's a reason all those DIY solar fanatics bought them up over the last few years, and they still fetch good prices used.

 

If you want more James has some 

[Tony1]

9 minutes ago, peterboat said:

If you want more James has some 

 

I must admit I wouldnt mind having one more, and I wish I'd taken your advice and got four of them, but its the logistics.

I was OK driving 400 miles when I was getting three of them, but I gave up the car last summer, and I dont fancy the idea of hoiking a 25kg battery all the way back up north via public transport. They seem ok when you first pick them up, but within 50 yards your arm feels like its dropping off. 

Plus with £150 of train/bus fares etc, the overall cost would be a bit too high for the benefit I'd get from having it.

When I make a trip down south to visit my daughter, I might give him a shout and see if he has any left, but at the moment its more of a nice to have than essential if I'm honest. The three I already have do the job brilliantly. 

 

 

[nicknorman]

10 hours ago, Tony1 said:

 

I ran it as admin and that seemed to get it working, thanks a lot for your help. 

 

The results were, I think, fairly decent.

The cells within each battery were all within 2mv of each other, so that seemed reassuring.

E.g. the cells in the first one were 3.299, 3.298, 3.299 and 3.300. 

The battery (module) voltages were 13.196, 13.187 and 13.194, so again not too bad considering I've not done anything to help them. 

I switched off the loads to try and get a level playing field instead of a steady drop in the charge, but all that did was to make the cells bounce back a bit, and increase in voltage slightly, so I'll need to repeat it when they have had some time to rest- but despite that, the initial values look reassuring, at least to my admittedly uninformed eye. 

 

There was one disconcerting thing though.

When I looked at the first battery, the SoC on the valence software showed as over 96% , which is not possible.

I fully charged them and synchronised the BMVs yesterday, and they've been running down since (with a bit of solar top up today), but its impossible they are at anything like 96% SoC. 

For one thing, the voltage was 13.19 (with a load of about 3 amps on them), and if they were at 96% SoC the voltage would be much higher. 

The BMV712s were all reading about 72% SoC, and interestingly, the second time I plugged the cable into that battery and read it, the reported SoC had gone down to 69%. 

I then rechecked the other two batteries, but they were still showing SoC of about 96%. 

So I'm not panicking about it, I'm assuming the method used by the software to calculate SoC must have a weak point in it, although its odd that one of the batteries did seem to correct itself to 69%, which roughly agreed with the BMV712s.

 

But apart from that anomaly, I'm actually amazed that the cells are so well balanced, after 18 months without a proper balance of any kind, and with my rather rough handling (and especially in the early few days of use, which included a brief excursion up to 15 volts). The valences do seem to have remarkable recovery powers.

 

Anyway, I've tucked them all in and read them a bedtime story, so they should be happy bunnies tomorrow. 

 

 

 

Hmmm 96 and 69 as mentioned above are identical ... if for one of them you are reading upside down ... (hint!)?

Anyway I wouldn't worry to much about the internal BMS SoC, maybe it's a bit like those SoC indications that you get with cheap solar chargers.

 

You should bear in mind that cell voltages around 3.2 to 3.3 are not relevant in terms of balancing. Something would be horribly wrong if there was a noticable difference at that sort of voltage, because the curve of SoC against cell voltages is extrememly flat. Out of balance is only detectable once the cell voltages rise up the knee, where any differences are massively magnified, say above 3.5v. I don't know if my cells are abnormal but I find that one really needs to get to 3.6v to be sure which is the "lead " cell, because the leader at 3.5v can become a lower one by the time 3.6v is reached. And of course it is what happens at 3.6 to 3.65v that is the important thing. This of course is why auto-balancing doesn't kick in until the cell voltages are fairly high.

 

1 hour ago, Tony1 said:

 

Guilty as charged your honour. 

Things is, I've never dared to contemplate the idea of setting up a 24v system, so that sort of balancing wasn't even on my radar. As is sadly all too clear to our readers, I have only the most ephemeral grip on the workings of 12v systems, so I'm happy to remain ignorant of the wizardy of higher voltages.

My (flimsy) defence for this misconception was that I watched couple of youtube videos I saw a while back (the perils of youtube video lessons....).

They talked about trying to arrange the cabling between the battery terminals so that it was of even length, in order to avoid the risk that one or more batteries might be consistently subjected to more charging/voltage/hassle/something else electrical. 

I then saw comments that balancing between batteries was 'a thing'.

That is where the accused made his fatal mistake.

I assumed that the battery balancing must be done in order to counteract some kind of gradual difference that would arise between batteries because of the physical setup/cabling/something else electrical. 

 

I honestly dont know why more people havent set up as marine electricians. There must be thousands of people like me who have a very limited undertstanding of the principles involved, and who would pay a reasonable fee to have someone safer and more knowledgeable sort these things out.  

As it is is, there are very few of them, you have to wait weeks to see one, and many don't like touching lithium batteries. 

 

 

As MtB says, I think far too much emphasis is placed on interconnect topology - always assuming that the interconnect cables are adequately beefy.

On your last para I would disagree - there are thousands of people like you who have a very limited understanding of the principles involved - and yet they set themselves up as marine electricians and take an unreasonable fee for screwing other people's systems up!

[Tony1]

11 minutes ago, nicknorman said:

 

You should bear in mind that cell voltages around 3.2 to 3.3 are not relevant in terms of balancing. Something would be horribly wrong if there was a noticable difference at that sort of voltage, because the curve of SoC against cell voltages is extrememly flat. 

 

 

Of course, that makes perfect sense (now you've said it).

 

On one hand I'm reluctant to keep on pushing the SoC over 90% too often, because I've already kept it between 65-85% SoC for most of the last two weeks, because of wanting to take advantage of the solar.  

 

But on the other hand I need to know how they behave when higher up the knee (or perhaps as high as the calf, as I now call it).

Certainly I would want to avoid the thigh region.

Which is not something I ever thought I'd say. 

 

 

[Tony1]

56 minutes ago, Tony Brooks said:

 

I think the clue is in "reasonable" fee. I have been out to help a number of boats since I put my website up and in far too many cases a fair time is needed to work out how the troublesome system has been wired and so on. That is before you start fault finding. It may look as if I was doing very little apart from making notes and drawings. After that you rectify the problem in a few minutes. Add traveling time to the total tome and the customer all too often does not consider the fee charged as "reasonable". In my case I never charged so the customers were happy.

 

Also Lithium technologies come in variety and it takes time to study and get experience of them. I doubt there are more than a handful of practitioners who feel they fully understand them. Personally I would not do anything with Lithium technology for a customer because I now I don't know enough about them - but gradually learning from several members here.

 

The phrase 'reasonable fee' for a boater, as usual, has to mean higher than a domestic professional.

 

Things are not as standard or predictable as domestic electrics (my electrics cupboard is a nightmare), and of course because there aren't very many, they usually have to travel at least half an hour and often more to reach you, so their services are just not going to come cheap. 

And this is why so many boaters of even modest knowledge will have a go at things like electrics- and thus the numbers of non-standard (and sometimes questionable) installations seems to grow and grow. 

 

[Tony1]

1 hour ago, MtB said:

 

Ah yes. The "£100? All you did was tighten that screw!" syndrome. 

 

Breakdown of bill:

 

Tighten screw: £1

Working out that a screw needs tightening, and which one it is: £99

 

 

 

 

 

This is what happens when an enthusiastic amateur starts meddling too much with electricity and things get out of hand.

Thankfully Ed Shiers took a quick look and seemed to understand what was going on, and he felt it looked ok (as in not going to catch fire in the next 5 minutes or so).

But it was much more difficult to explain to him why I ended up with this overly complex jumble. 

 

Edited March 10, 2022 by Tony1

[nicknorman]

I’ve seen worse! But shouldn’t that thick black cable with ring terminal somewhere near the top, be connected to something? Unconnected thick cables flapping around near bare red wires makes me nervous!

1 hour ago, Tony1 said:

 

Of course, that makes perfect sense (now you've said it).

 

On one hand I'm reluctant to keep on pushing the SoC over 90% too often, because I've already kept it between 65-85% SoC for most of the last two weeks, because of wanting to take advantage of the solar.  

 

But on the other hand I need to know how they behave when higher up the knee (or perhaps as high as the calf, as I now call it).

Certainly I would want to avoid the thigh region.

Which is not something I ever thought I'd say. 

 

If you never take cells up the knee or down the knee at the other end then it doesn’t matter if they aren’t balanced. On the other hand it doesn’t hurt to do it occasionally to check for top balance and allow the BMSs to do their balancing thing.

[Slow and Steady]

48 minutes ago, Tony1 said:

This is what happens when an enthusiastic amateur starts meddling too much with electricity and things get out of hand.

All things considered, that looks quite neat to me. Mine's all jammed into an almost inaccessible cupboard, is the original installation and TBH looks no better than yours. When I start fiddling for Lithium I think I'll have to take the cupboard apart just to see what's really going on. Trouble is all the engine controls and gauges are mounted on it amidst the spaghetti - I would gladly spit on the bloke who installed the inverter/charger right at the back of this narrow cupboard.

Edited March 10, 2022 by Slow and Steady

[Tony1]

20 minutes ago, nicknorman said:

I’ve seen worse! But shouldn’t that thick black cable with ring terminal somewhere near the top, be connected to something? Unconnected thick cables flapping around near bare red wires makes me nervous!

 

 

Eyes like a hawk! 

That's actually the negative from the shoreline charger, when I shifted the fuses and bus bars around that cable would no longer reach the negative bus bar.

But by the time I finished it all (the last bit was placing the victron battery protect as the high voltage emergency disconnect) I was so fed up with electrical shenanigans that I couldnt even be bothered doing another cable for the shoreline charger, so I left the cable hanging, closed the cupboard door, and vowed not to look in there again for another 6 months! 

 

Oh, the shame......

 

[Tony1]

15 minutes ago, Slow and Steady said:

All things considered, that looks quite neat to me. Mine's all jammed into an almost inaccessible cupboard, is the original installation and TBH looks no better than yours. When I start fiddling for Lithium I think I'll have to take the cupboard apart just to see what's really going on. Trouble is all the engine controls and gauges are mounted on it amidst the spaghetti - I would gladly spit on the bloke who installed the inverter/charger right at the back of this narrow cupboard.

 

To be honest that was actually the wardrobe, but I wanted to keep the lithiums indoors so I emptied it out for use as an electrical cupboard. So all that stuff is just for batteries, chargers and the inverter, and there is a smaller electrical cupboard nearby with all of the 12v wiring and the 12v panel etc. 

My clothes are now stashed all over the place, but at least my dear lithiums don't get too chilly. Because that would be cruel.  

 

 

Edited March 10, 2022 by Tony1

[Tony1]

37 minutes ago, nicknorman said:

If you never take cells up the knee or down the knee at the other end then it doesn’t matter if they aren’t balanced. On the other hand it doesn’t hurt to do it occasionally to check for top balance and allow the BMSs to do their balancing thing.

 

Oh those little buggers will be going up the knee alright, but its a bit soon after the last full charge.

Its only two days since they got up to the groin, so I'm giving them a couple of days more on light duties.

 

[TheBiscuits]

Just now, Tony1 said:

 

Oh those little buggers will be going up the knee alright, but its a bit soon after the last full charge.

Its only two days since they got up to the groin, so I'm giving them a couple of days more on light duties.

 

 

Have the laptop connected when you do so to allow the top balancers to work.

 

Do you have the batteries daisy-chained on the BMS wires or are you connecting to each battery individually?  The Valence software should be able to talk to each battery in the bank without you needing to keep unplugging the laptop cable.

[Slow and Steady]

6 minutes ago, Tony1 said:

To be honest that was actually the wardrobe

I think starting again might be my best bet too but I don't want any of it in the bedroom. I may have to provide some low level heating for the batteries. I'm very tempted to get Ed 4 counties in too do the lot and shut my eyes to the apparent expense because I see others going around a spiral of expensive experimental mistakes and I'm not immune to that either. Do it once and do it properly seems usually pays off.

[Tony1]

Just now, TheBiscuits said:

 

Have the laptop connected when you do so to allow the top balancers to work.

 

Do you have the batteries daisy-chained on the BMS wires or are you connecting to each battery individually?  The Valence software should be able to talk to each battery in the bank without you needing to keep unplugging the laptop cable.

 

Thanks, yes I'm planning to connect the laptop next time I do a nearly-full charge.

They've been charging a bit today but its only 15-20 amps from the solar, so not really enough to push their voltage up much at the moment. 

 

The batteries are connected up in a chain using their AMP type connectors, and I did expect that plugging the laptop cable to the last battery would allow to me to read them all, but it didnt work out. I had to connect the laptop cable to each battery in turn.

It'll be something I'm doing wrong no doubt, but tbh just being able to monitor at cell level is a huge improvement, so I'm more than happy with that at the moment. 

 

[Tony1]

7 minutes ago, Slow and Steady said:

I think starting again might be my best bet too but I don't want any of it in the bedroom. I may have to provide some low level heating for the batteries. I'm very tempted to get Ed 4 counties in too do the lot and shut my eyes to the apparent expense because I see others going around a spiral of expensive experimental mistakes and I'm not immune to that either. Do it once and do it properly seems usually pays off.

 

I couldn't recommend him highly enough to be honest, absolutely top bloke. He even waived part of his fee on the first day because he didn't feel he'd made the progress he wanted to make, even though I was quite happy with things. 

He can fit an alternator regulator for you that will handle all of the charging, and will be much simpler and more efficient than all the gubbins I've put in. 

He can even fit you a better alternator if your set up can fit it.

Out of interest, he said he thought it would be ok for my lithium batteries to be left out in the engine bay (I covered their ears when he said this.)

 

If you do go lithium, I would also give some thought to solar, because they seem to really take in a solar charge very well. 

 

[TheBiscuits]

4 minutes ago, Tony1 said:

The batteries are connected up in a chain using their AMP type connectors, and I did expect that plugging the laptop cable to the last battery would allow to me to read them all, but it didnt work out. I had to connect the laptop cable to each battery in turn.

It'll be something I'm doing wrong no doubt,

 

You will have to make a data connection to each battery but it should work with the cable connected at one end with the batteries linked together.

 

Look for a setting/drop-down box in the software interface when they are all wired together.  You might also need to do a scan of some sort to let the software find all three modules.

 

Sorry I can't be more specific without having the connected software in front of me.

 

 

@peterboat might be able to help once he can stop telling you the software won't work on your laptop ...

[TheBiscuits]

 

This video might help you, he's a non-techie bloke doing exactly what you need.

 

Do you have a terminator on the other end of the daisychain?

[Slow and Steady]

31 minutes ago, Tony1 said:

 

I couldn't recommend him highly enough to be honest, absolutely top bloke. He even waived part of his fee on the first day because he didn't feel he'd made the progress he wanted to make, even though I was quite happy with things. 

He can fit an alternator regulator for you that will handle all of the charging, and will be much simpler and more efficient than all the gubbins I've put in. 

He can even fit you a better alternator if your set up can fit it.

Out of interest, he said he thought it would be ok for my lithium batteries to be left out in the engine bay (I covered their ears when he said this.)

 

If you do go lithium, I would also give some thought to solar, because they seem to really take in a solar charge very well. 

 

Yes definitely solar, you'd be crazy not to. I also have travelpower which he rates using with a 240v charger as a more simple and cheaper way forward - a kind of head start at least.