nicknorman

Maybe it was a typo?

A proper system! I would just say that 2hrs absorption seems excessive even bearing in mind the caveats you mention. Once the voltage has hit 14.0v (which is presumably when the absorption timer starts), I would have expected the current to have fallen below 5% in 15 to 30 mins, and holding the voltage up at 14v after that doesn’t really achieve anything, and does slightly stress the batteries. Might be worth observing the behaviour / charge current during the absorption phase after you have discharged below 70%.

I think it is reasonable in theory. It’s the same idea as connecting the boat alternator to the domestics and then using a split charge relay to charge the starter - because the domestics need the most charge. 4A does seem quite low but led lights on modern vehicles don’t take much current. It seems to work for them, anyway.

Yes. Although personally I have enough reasons already!

There is a stoppage notice about it. Definitely not available to passing boats. https://canalrivertrust.org.uk/notices/30146-fazeley-mill-marina-facilities-birmingham-fazeley-canal

New signs at the entrance say something like “welcome to Fazeley mill marina” “private marina, no entry”, which is somewhat oxymoronic. I guess it would still be possible to rock up in a boat and use the elsan, but that is verboten by the “head of marinas”. And not on Thursday or Saturday when the office is manned.

It is. And FMM is not really a marina any more, it is a moorings with very intermittent services, no caretaker/supervision for 5 days out of 7. And although they have finally partially sorted it after 6 months, no security. One could walk in under the bridge and walk onto our pontoon. Not great for an urban “marina”. They cut down the protective vegetation under the bridge and declined to fix the pontoon gate lock. Now 6 months later they have just installed fencing under the bridge but still no pontoon gate lock. One thing which really tickles me is FMM’s new website. See screenshot below. Slight problem, FMM is not in Warwickshire, it is in Staffordshire. Oh and it is not on the Coventry, it is on the Birmingham and Fazeley. So they don’t seem to actually know where their new marina is! That website has been up for about 6 months, they haven’t noticed!

It’s certainly closer to Aberdeen, but since my mother lives near Stratford on Avon, we still need to drive the same distance when we go to the boat because I feel obliged to visit her as well - she is after all 102 now!

Will be in Aston (Stone). But currently we are homeless , in transit. I suppose that makes us Continuous Cuisers!😱. But only for 3 days😇 Probably not😱

Yes same as previously mentioned. We are still in transit but popped into the new marina to deposit car and then get train back to collect the boat. Although the marina office person was different from last time, we received the same very warm and friendly reception. Chalk and cheese from the new order in FMM. Although to be fair, FMM has a new chap in the office (just 2 days a week) and he is great, but above him is the hostile regime so I doubt he will last long, he is too nice!

After 14 happy years in Fazeley Mill Marina, we have departed. Since Rothen Group bought it last autumn, the atmosphere from “the management” has been hostile, derogatory and we feel despised. Everything done is about the needs of the Rothen group, moorers needs do not seem to figure at all. Not the slightest concept of customer service or being in the leisure industry. Not prepared to put up with that so we are moving to another marina which as well as being much, much nicer and massively friendlier, is also £500 a year cheaper. It’s a no-brainer. FMM now looking very empty since lots of people have left. Maybe they have a plan to fill it in and build houses once those pesky moorers are got rid of? Or maybe it is a tax loss vehicle? Who knows, it is all very odd. It’s hard to believe they are not being deliberately unpleasant. Lengths of empty pontoon, this is just a small sample…

Yes.

Set at that when I received it.

My 105Ah Fogstar drift is set to about 14.3. Which is quite low.

It was certainly the case that when I first got my Fogstar the SoC was absolute rubbish. First time I put on the microwave (just under the max current) the SoC plummeted to zero almost instantly. And when I put on the 0.4C charger, it jumped to 100% very quickly and long before the battery was full. But after a few cycles it became OK.

In my experience - of which zero is with a kestrel reg - decent modern alternator controllers bring big advantages in lead acid charging. So whilst a standard 14.4v built in reg is OK, a good modern (digital) alternator controller is much better.

That’s interesting, I didn’t think it could do that. Must have come about in a firmware update… Always something new to learn!

Not necessary, but beneficial only in that it can be useful to have a backup/alternative/independent indication of SoC. For example if for some reason you need to disconnect the BMV display from the shunt (as I did when I stupidly dropped something heavy on the shunt and damaged the RJ45 socket on the shunt) - when you reconnect the previous SoC is not remembered and goes to 100% (by default). An ability to look at the BMS SoC and copy the value to the BMV gives a reasonable starting point pending the next sync to 100%.

But set against that is the temperature coefficient of the BMS MOSFETs - MOSFET on resistance increases with temperature, so there is a degree of current balancing between batteries in parallel. And interconnect resistances are very small unless there is a poor connection. My 12 cell Li battery (3P4S)doesn’t have equal interconnect lengths (due to battery box space constraints) but I am unable to detect any difference is current flow from the groups of 3 cells in parallel under heavy load. This is why battery manufacturers tend to allow perhaps 4 batteries in parallel.

Maybe be not but I’ll just point out that 20% is not low. 20% or even 10% or even 5% is much better for the battery than 100%. Although of course one has to go to 100% from time to time to sync the SoC. Delete the lead acid paradigm “low SoC is bad for the battery”! It’s hard but you gotta do it!

If you analyse what you are saying, it is actually that one member from a membership of hundreds, doesn’t welcome your questions. The rest of us do. So do you want to bow to the wishes of one person, or stick with the rest of us, who have tried to be helpful? And in fact I would say that the member in question does welcome your posts as it gives them an opportunity to be nasty, which seems to make them feel better. Consider it a duty along the lines of “care in the community”.

Your first emboldened point does raise a theory - perhaps the old fashioned BEP uses a fairly low resolution ADC with an “autoranging” function whereby gain and or offset are switched to cover the full dynamic range of the meter. 50A is mentioned as a possible “range change” point, so it could be that the meter reads correctly up to 50A, then inaccurately above due to a circuit fault in the auto ranging bit. It would be interesting to see readings just below, and just above 50A as measured by the BMV. But anyway I don’t think it’s an issue with the shunt.

I don’t see what the presence of the safety vents pointing at the BMS has to do with battery orientation. If the vents decide to breach, the high pressure liquid and gas coming out is not going to be particularly concerned about the direction of local gravity. And anyway, the BMS is already likely to be knackered as it was clearly not doing its job properly.

Normally an inaccuracy would consist either of a zero offset (meter reads something when it should be reading zero), or a scaling error (meter reads something fraction (or %) of what it should read). It seems relatively unlikely (but admittedly not impossible) that a meter would be accurate up to a certain value, then suddenly very inaccurate above that value. Perhaps getting some more comparison data at different currents might shed some light.

That seems to be wired correctly. The BMV wiring to the display can't really be done wrong as it is just a matter of plugging in the connector, but I come back to the little wires on the BEP shunt and/or the possibility that somehow there is a negative connection between the actual battery negative and the BEP. It is important that as far as the BEP is concerned, the negative is the point between the 2 shunts, not the battery negative. So nothing connected to the BEP display should be connected to the actual battery negative, only the "pretend" negative between the shunts. If that fails, you could swap the BMV and BEP around. It's a good theory but the connections for the BMV is via an RJ45 plug/socket, whereas the BEP just uses loose wires. Not really possibly to get them the wrong way round.