nicknorman

I’m sure forum history will commend you for doing the job of head prefect with vigour and vim and keeping us all in order. Many congratulations!

I used a PIC 18F26K83 which has built in CAN as well as a load of other peripherals. Cost a couple of quid. It’s only an 8 bit micro but perfectly adequate for the job. I agree about the RJ45. I used them myself but the controller is in the engine room so it’s warm and dry. Yes certainly weatherproofing is important for their target market but my point was that less than perfect weatherproofing isn’t much of a negative point for most canal boat applications - what is needed is tolerance of high relative humidity. Yes. Certainly component obsolescence is a constant worry, but it applies to just about anything fancier than a resistor! The chip I used is obsolete now, but there are other new ones. One would just have to change the driver software to adapt to a different device, 95% of the product would be unaffected.

It is primarily relevant to lithium batteries. You need something “smart” to avoid mechanical overloading at low rpm, to avoid overheating the alternator and to go to float when the battery is full to avoid overcharging it. The primary benefit of the Bluetooth link is for configuring the settings using the Zeus App.

Ah yes you are right about the resistors. I blame the slightly blurry pic! An alternator reg chip gives you: Speed input (from the W) to allow reduced field current at low rpm and to avoid wasting field current when the engine is not running (and indeed to allow the thing to be permanently powered up but sleeping. Think 6 diode machine). Just processing the W input with its wide range of voltages is a bit of a deal. It gives you field current measurement, voltage measurement, ability to specify a field current limit, control over field current ramp rates/ soft start, adjustable regulated voltage, the actual control MOSFET and its driver circuitry. Most of which you can’t get with just a mosfet and an opamp! And all for under a tenner even in small quantities. I just don’t understand why you would go to the time and expense of reinventing all that.

Very true.

If you say so. You are confused. I want to discourage newbies like that from posting on CWDF. So I’ll accept the praise, thank you.

Thanks for that, very interesting. Fascinating to see how others have done it but to be honest I’m fairly surprised that they have made it so complicated. Why not just use an off the shelf alternator controller chip and a micro controller with built in CAN controller. No need for lumping great electrolytics. And why have they used through-hole resistors, no-one does that any more! The board does look sparsely populated but perhaps they needed a fairly big board for MOSFET heat dissipation. To be fair their design does work with + and - controlled alternators but OTOH if you are going to do surgery on the alternator to cut out the regulator, it’s not really much more effort to reconnect one of the brushes to negative and thus only need a positive regulator. Obviously weather protection is your thing but IMO for a typical narrowboat installation I don’t think significantly waterproofed case is necessary. Even in a cruiser stern installation, provided you keep it away from drips etc I think it is only dampness that needs to be protected against and so the lack of a conformal coating does seem very surprising. Anyway, the proof of the pudding etc so it will be interesting to hear how you get on with it.

No but the point is should he ever want any more advice (which I agree seems unlikely) then he won’t be getting it from me. And I suspect not from the other usual suspects. If you want people to help you, you don’t go around calling them “condescending” when they have just been doing their best to be helpful with very limited information. On the other hand, as seems likely, if he just enjoys winding people up or is so sociopathic that he doesn’t care, nothing is lost. But if he doesn’t realise how he came across, it seems only fair to point that out before he falls out with more people. He can take it or leave it. Oh and while I’m on, I’ll mention that the importance of your opinion of me is somewhere between insignificant and miniscule. If I have time later I’ll get my microscope out and see if I can spot it.

He deserves to know how he made me feel.

Your posts didn’t offend me, but they did irritate me a bit. You started off with a very general question which gave the impression you didn’t know much. I spent some time going over the basics in my replies. Yes basics, but it still takes time and effort to write the words. Then it seemed you had intentionally tricked us by not mentioning that you were going to go for Lithium batteries. And then shortly after asking for help and me spending some time giving it, you changed your mind and decided you didn’t want any help. And now we are condescending apparently. All of which leads me to believe that you are quite an annoying and high maintenance person on whom I shall certainly not be wasting any more time.

Jolly good. Do let us know how you get on once it is all put together and working.

Ah well, that is a whole new can of worms!

Not sure if that is a statement or a question! You did say "3 leisure batteries". I have leisure batteries too. They are lithium! But I presumed you meant conventional lead acid wet leisure batteries.

Yes I fogot to mention battery monitoring, which is silly because it is something I am always recommending! Personally these days I would go for the BMV712 because the bluetooth link to the phone is so useful. I disagree somewhat with Tony on the advantages of alternator add-ons. I used to share his view until I installed a precisely controlled alternator controller (this was as a precursor to fitting Lithium batteries, but I still had the lead acids for a while). I found that the modern digital regulation did make much more difference than I expected. Tony is correct to say that a battery will only take so much current, but in practice the regulation of a conventional built in alternator regulator is very poor in that there is long period where the maximum current it can supply reduces, long before the charging voltage reaches the regulated value of 14.4v or whatever. It really does make a big difference during the mid-charging phase, although it is of course true that the lengthy tapering off of charge current to reach 100% state of charge once the voltage has reached 14.4v, still has to be endured.

If you just have lead acid batteries and one alternator then there is not much complexity that can be created! Just use a VSR as previously mentioned, to connect the engine and battery banks together when charging is taking place. Using a VSR is slightly better than a split charge relay because the latter is associated with charging from the alternator only whereas a VSR keeps everything charged from a battery charger or solar. So looking at other sources of charging: Solar is very popular these days, and for good reason. Prices are down and efficiency is up. But it depends on your type of usage, which I don't think you've mentioned. Certainly if you are a live aboard it would be crazy to not have as much solar as you can reasonably fit on the roof (whilst still allowing access to lock ladders etc). On the other hand if you tend to cruise for long days every day, it is not worth it. But then again, for 3 months of the winter solar does virtually nothing so you need another means of charging and this of course could be your boat engine with the VSR already mentioned. But another way is to use a generator (a quiet one please!) and battery charger. And the battery charger does also allow you to charge from shore power if you are in a marina or some moorings where there are electric bollards. If you are going to be running the engine a lot just to charge the batteries, it might make sense to use some sort of external alternator controller, since the built-in regulators suffer from current tailing off long before the regulated voltage is reached, and this slows charging. Adverc used to be the popular one, not sure if that is still sold. Or a Sterling one. The Alpha Pro is a good regulator but very expensive and I'm not sure it is worth it for lead acid batteries. Plus you need to do a certain amount of surgery on the alternator to access the field circuit directly.

Yes but that was not due to CO from a flame touching a metal pan etc. That was from severe incomplete combustion caused by lack of oxygen due to closing the drill door. No doubt had they been able to see it the flame would have been yellow and sooty. My “very small” relates to the CO produced when an otherwise good flame plays on a saucepan etc. Certainly, any time there is a “bad flame” (yellow and sooty) there is plenty of CO being emitted.

This is of course correct, but the amounts involved are very small. Our CO detector is within about 5 feet of the hob but it has never come off 0 during cooking. Nor even when I bring it closer. Presumably with the CO being mixed with hot air and hot CO2, it rises quickly to the top of the cabin and then out through a mushroom vent.

You poor thing, have you been triggered? I can recommend a good councillor. But then again, since your easiest option is simply not to visit this site again, the fact that you have started a new thread is a clear indication that in fact you want attention and reasons to feel aggrieved. We are quite good at giving that - for free! You are welcome. Well let's hope they decide not to. If everyone who started a thread had the option to have it all deleted when they didn't like the way it went, that would be a major discouragement for bothering to reply at all.

Yes it’s a good point. I got the Li battery in the early winter and so far, what with snow on the panel, the panel blowing over etc etc, the solar has never got even close to fully charging the battery. But in summer, it will do. Which is a good reason for getting an MPPT controller! It’s actually also a good point in relation to charging with an alternator which is intrinsically fairly rippley. In our case the Combi input capacitors act to smooth out the ripples a lot, but a system with just an alternator and no large capacitors in the system, is going to have plenty of ripple. At some point I might take my ‘scope down to the boat and check out the ripple with and without the Combi in circuit. Probably the ripple won’t be that bad at lower SoC due to the very low internal resistance of the Li, but it will be interesting see the ripple as the batteries approach 100% and the current is tapering.

Our CO detector always reads zero. Well it should do. A couple of years ago it started showing a reading whenever the stove door was opened to refuel etc - and it is not close to the stove. To cut a long story short I removed the flue pipe because it was choked up with a very hard concrete-like deposit and at one point near the stove, the clear diameter was only about an inch. Cleared it all out with a long chisel etc and since then it has been fine with always 0 on the CO detector. So probably your flue is severely restricted. Personally I disagree about removing the baffle plate, the plate is there for a reason and helps improve the efficiency of the stove, but you do need to clean out the space above the baffle plate from time to time. If it is anything like our flue was, sweeping it is ineffective because the deposits are rock hard.

Ah well here we run headlong into the problem of mixing batteries of different chemistries. The LA wants a tail current setting of 2% or less, the Li wants a tail current setting of 5%. Which is appropriate? There is only one way to find out. FIGHT!

Well it wouldn’t be too hard to link a Victron charger with something that measures battery current such as their BMV712 or Smartshunt. Then the charger would know when to stop charging (when the input to the battery fell to 5%C). By the way, I checked the Fogstar recommended charge profile, they use EVE cells and have this to say about charging them - the ubiquitous 0.05C aka 5%C again.

This is presumably because the charger doesn’t know the battery current. Charging to a specified voltage without regard to the current results in potentially a very large variation in final SoC depending on the relationship between charger output and battery capacity. Certainly with a 2 hour absorb time the current is going to have fallen way off so the battery will be fully charged even if charged at a high C rate, but holding the voltage up at 14.2 for about 1:45 longer than necessary is not optimal. The battery may be slightly over charged. As we have said, unless there is something wrong with the cells, they do not go out of balance so even with a crappy BMS that needs the voltage to be held up whilst balancing is taking place, in practice there will be no balancing going on during the 2 hours. Victron don’t make cells. They just assemble batteries. So they, like so many other people, have adapted their LA chargers to roughly suit LiFePO4. Sub optimal!

It might even be 3.55, I can’t remember. On the other hand since they specify 14.4v as the charge voltage, it’s probably 3.60v. On my own system I use 3.65v as the start of the alarm, I think 3.70 is the disconnect voltage, but since I only charge to 14.3v for a 100% charge (and that is only done once a month) these higher voltages should never be reached. Balancing is triggered if a cell goes over 3.60v but the balancing continues for a calculated period of time regardless of what the charge voltage subsequently is - ie even if the system stops charging. However in the past year, balancing has not been triggered. Again we are up against the issue of whether the BMS disconnect is used routinely as the charge control, or whether it is there as an emergency backup disconnect. Wrong. I would make it 5%. Assuming the system can charge at over 15A. Although it also depends on what voltage settings you have set.

The BMS settings can be changed, but you are prevented from doing so by needing the password. I think Fogstar will give you the password but will also note that your warranty will be invalidated for anything to do with cell problems arising from over or undercharge.