nicknorman

If the Beta setup is the same as ours, there is no need to and in fact it would be a bad idea. The alternator can already produce about 135A at idle and this is a big load on the crankshaft bearings/pulleys/belt etc. The engine, belt etc struggles a bit with this due to the high torque load. By about 1000 engine rpm the alternator can make nearly full output. If the engine pulley was made smaller, all of this would get worse and the engine would struggle more, the belt more prone to slippage and all for naught. If the system is working properly, it is excellent and no need to tinker. If it is not working properly the correct course of action is to fix the fault rather than do stuff to disguise the fault.

As an aside to this I would just mention that you have to be quite careful with sustained high currents. It is very easy for something with a slight resistance to get very hot! Melted battery isolators etc! I use a BDS-A latching relay as the battery emergency disconnect, it is rated at 190A at 85C ambient and 260A at 25C ambient, but it still gets very hot at 200A sustained charging current. Not sure what the margin to melted plastic is! Makes me a bit nervous so I tend to avoid charging at more than about 150A.

You must be dropping some voltage in the wiring between alternator and batteries. I would expect the standard Iskra 175A alternator to be putting the full 175A into the Li battery without any fancy controller. Ours did, anyway. Check the voltage between the Iskra terminals (fat red B+ wire, and casing) and again at the battery terminals with engine running at 1200 rpm and the travelpower off. I suspect there will be a considerable difference. Then it is a matter of checking voltages along the route to see at what point the voltage drop is happening. For example the alternator may route through the battery isolator whereas the Victron probably doesn’t. The other possibility is that there is a blown diode in the alternator, this would result in reduced output voltage. So tell us the alternator terminals voltage and current when charging without the travelpower. The only need for something like a Sterling A2B is to REDUCE the current to avoid the alternator overheating!

Today I did a complete cycle of the 105Ah fogstar at home. This being to hopefully allow the BMS to calibrate itself properly. I discharged it at around 6A and it ran on for quite a while below 0% SoC before low voltage cutout at 2.75v / cell. Voltage split was not a lot (unfortunately someone phoned me at the wrong moment so not exactly sure what it was). Put it straight on to charge using the Fogstar 40A charger. Which does actually charge at 40A up to at least 50% SoC, but the fan is REALLY noisy! Anyway it's just hit 105Ah / 100% on the App but still 24A going in so clearly the capacity is a bit more than 105Ah. I noticed previously that the high voltage cut out is set to a conservative 3.6v. Oh and cell balance "up the knee" at 3.595v is max 5mV split which is pretty good. App is still saying 105Ah though, not sure if it would adjust itself to the actual capacity it discovered when I cycled it. Seems not. It is still incredible, for someone used to LA batteries, that with the SoC at 5% it is still chucking out 12.8v at 6A discharge. Definitely a bucket of electricity!

I think both are right. Replacing the core is easy. Gaining access to replace the core in the confines of a boat might be a PITA!

Kubota is a Japanese company so I doubt they have any engineers in the UK and anyway they just make the base engine which is used in a lot of agricultural machinery. They wouldn't know anything about boats. Beta Marine are the people who buy in the base engine and then convert it to marine use. However I don't think they really have any engineers for general maintenance. I think your best bet is to try to find a reputable marine engineer in your area. Unfortunately we are based in W Midlands so I don't know anyone in your area, but others might. There is RCR (River Canal Rescue) which has national coverage but I am reluctant to recommend them because there have been a number of adverse reports and in particular they quite like recommending a "refurbished" replacement engine, which by accounts is not in great condition. If you do go to RCR, don't let them talk you into a replacement engine! By the way, you talk about refilling with water - maybe you didn't mean "just water" but be aware that you need the correct amount of antifreeze not just for anti-freezing, but for corrosion protection as well. On the other hand no point in pouring in antifreeze if it is just going to pour out again! I guess it may not matter too much for a short period, but you don't want to leave a very weak solution of antifreeze in the engine for too long.

You do have a bit of a thing about LTO. The main disadvantage apart from those already mentioned, is the big range of voltage during discharge, compared to the very flat voltage profile of LFP. And it is difficult to get an integer number of cells that gives a voltage compatible with 12v systems. Compare the flatness of LFP with the unflatness of LTO With LFP, 4 cells gives you from 13v to 12v over pretty much the full discharge range. With LTO if you have 5 cells it is 13v to 10.85v - too low. And with 6 cells it is 15.6v to 13v - too high. And just too much variation to be useful.

Beta 43s have varied a bit throughout the years but our 2011 model is filled from the rectangular "box" above the exhaust manifold. It is important to note that if yours is the same, you do not fill it right up otherwise it will just overflow the next time you run the engine and the coolant heats up and expands. The correct level is about 1" below the neck when cold. If you put more in than that, it will just disappear into the overflow. I just wanted to check that it was actually leaking and not just a case of over-filling!

Do you know the total hours on the engine? It would give an idea of whether the engine is generally knackered from old age, or just needing some localised fettling. It's not particularly difficult to replace a core plug - access is the usual practical issue. Is it a domed type or a cup type? The former needs a good thwack in the middle with a wide punch to splay it a bit to make it seal, the latter can be inserted with eg a socket head a bit smaller than the cup. In both cases I'd use some appropriate sealant. One also has to ask why the core plug went in the first place. This may be due to corrosion due to not changing the coolant often enough. The antifreeze doesn't lose its anti-freeze capability but it does lose its corrosion inhibiting properties. Normal blue antifreeze should be replaced (by draining and refilling the cooling system) every 2 or 3 years ideally. If there is a lot of corrosion inside the engine due to not replacing the coolant, then other difficulties may manifest themselves.

I blame Brexit. The butlers all returned to foreign parts.

My battery is in my caravan where it has been -7 for a couple of days. So it was interesting to try out the heating side of things. The battery duly refused to take any charge but it was taking about 3.5A for the heaters. The temperature gradually crept up but it didn't start charging when it got to +5, I'm not sure when it would have done so because I cycled the charger and then it started charging. Having proved that point I stopped the charging again. I think keeping the charge off for a while after the temperature indicates +5 makes sense because both the heater and the temperature sensor are on the outside of the cells, and it must take a while for the heat to propagate into the interstices of the cell which is the bit that actually matters. Anyway all that did highlight another slight problem. As previously mentioned, that BMS's SoC estimation seems pretty rubbish - although I'm going to fully cycle the battery a few times to see if that helps. My fallback position was to continue to use the BMV712 but that is problematic - when the battery is cold and not taking charge, the BMV sees the voltage up at 14.3v and just 3.5A current. This is below the BMV's "fully charged detection" threshold of 5% (5A) and so it resets to 100% SoC even though the battery might well be very low. Hmmm... I suppose I could go down to a 3% "fully charged" figure but that is not the optimal value which is 5%. In better news it has occurred to me that I might as well get into the habit of taking the battery home during the week, to charge. There is a massive difference between a 105A Li battery vs the 2 x Trojan T105s ( which had similar usable capacity) in terms of weight and propensity to leak sulphuric acid over something. Carrying the Li around is trivial.

I've only done it after refilling the coolant - when it is still cold. I found I just needed to back off the compression fitting nut 1/2 turn or so, air could be heard hissing out. There was no possibility of the pipe disconnecting.