magnetman

The Orion XS 50A is non isolated. The 30A version is isolated. BuckBoost 50 is the previous name of the Orion XS 50A.

Victron AGM batteries are very good quality. Not cheap but if you don't want to do lithium because it is complicated AGM is still a valid solution specially for a Boat which is cruising rather than moored when occupied. Obviously being able to cram in as much charge as possible in a short time is desirable for someone who moors for two weeks then moves because the law says they should. For someone whose Boat tends to be moving for several hours per day the advantage is less significant. People always used to do OK with lead batteries and they can still do the job on a Boat which is not set up like an apartment.

The Victron 50A B2B does look good to be fair as it seems to allow user settings for charge profile and current. Quite attractive. Easy enough to have an alarm for alternator case temperature.

LTO is an interesting option. I have been experimenting with 6S LTO modules and they don't seem to be bothered about much. I've had one of them down to about 4v (no BMS) and it charged up normally cells are still within 3mV of each other. Also the top voltage is 16.8v. Mid range maintenance voltage between 14 and 15v. Not done any alternator testing its just been solar so far but I will be doing some experiments. Also excellent for engine starting I use a 40Ah module charged to 15.2v to start the Perkins P4 its does it happily. They are generally rather expensive batteries but if one were to have a multi cycle charge discharge regime the battery banks can be smaller. I have marked the module which went right down (lights left on) and interesting to see if it suffered at all. It appears not. LTO have very high cycle life and also huge C rating. 10C is easy. i took apart a Suzuki Swift mild hybrid battery. It has a 3Ah 5S LTO battery which is nominal 12v 3Ah. Tiny. The battery has a 150A fuse despite being so small. This is used in the car to add power while moving from a standstill then recharged. I believe the in/out rate is probably something like 20C in use which would mean it was supplying nearly 1HP for a short time. It might be more. The 150A fuse was interesting. Yes 6S is a bit high for normal 12v loads but easy to put a buck converter on lights and pumps circuit. Inverters cut out at over 15v which is about 85% charged so a happy battery. LTO ocv soc graph . So roughly 40-90% is 2.2-2.5v which for a 6S would be 13.2-15v. Not too terrible. Space above for safety.

It would be very easy to have two negative terminals. One attached to the BMS for loads which may discharge the battery while unattended and the other one for heavy discharge such as starter motor and connected directly to the terminals. I have a battery like this.40A BMS or connect direct. It was home made by someone who is an EV industry professional. Seems an interesting approach I think. Yes that is basic economics but if lithium batteries become universal then it seems demand would go up. Is it not plausible just to have say a 65A alternator which will charge a LFP battery and switch itself off after a certain amount of time? If one knew how many Ah one wanted would it not make sense to put a timer onto the regulator.

I wonder how many others use lithium batteries for starting the engines. Alternators do need to adapt to lithium batteries at some stage and it should not mean a regulator costing hundreds of pounds.

Is there any reason why the MPPT would object to a voltage which was not jumping around? Presumably with solar panels with no shade and a sunny day this would be quite a common outcome.

I have endless room in my head for batteries. I suppose people do have space constraints which is why the drop in thing exists in the first place. One day these problems will be solved when infernal combustion engines are banned. See above Its an interesting question. i wonder if it is good for the makers (lets say Victron) to keep these two products separate in order to shift more blue items in flash boxes. They might be electronically very similar. I don't know but have difficulty working out why the output from an alternator through a battery would be so different from a solar panel.

24v Alternator 55A is £150 (prestolite lucas a127) Couple of cheap lead acid batteries £150. I already have a 50A MPPT which is surplus in winter. In summer the vast majority of the electric is dealt with by solar panels. 50A b2b would be £300. It costs the same. I think the 24v alternator might be better for thermal management as there are fewer amps coming out of it. Which would mean one could eke out more power with less risk of overheating. I expect a good alternator controller solves these problems but how much do they cost?

The Boat domestic system is run by a 12 (13) volt LFP bank. The only 24 volt parts would be the alternator and the small Lead battery bank. This would be routed via the MPPT (might not work) to the LFP battery bank which would be 12/13v. I was proposing repurposing a high current MPPT for winter when their is naff all solar. Making silk purses from sows ears seems quite a wise move to me in a number of different ways.

Cheap and cheerful alternators? Also did you check the operating temperature range of the alternators?

The system I was referring to has dual alternators. The starter would be 12v.

One of those cheap single induction hobs would be good because they have power settings from 300w to 2kw selectable. Maybe more ventilation is needed for these alternators.

If you have a big inverter and heavy load like an immersion heater which the inverter can run you could test the alternator that way. IR thermometer to hand.

Maybe A 24v alternator, 2 LA batteries to make a 24v bank and the MPPT repurposed for winter to charge the LFP batteries via alternator-LA battery-MPPT. In summer the solar does the job and the other alternator is still 12 volts.

30 amps seems quite a low charge rate. Is it also the point at which Victron B2B hardware gets a lot more expensive? I do idly wonder if my 50A Victron MPPT for the solar panels could be repurposed and used as a B2B in winter if I wanted to charge batteries using the main engine. Sun is predictable due to seasonal changes so there would be a certain point where whipping out the 50A and replacing with a 20A MPPT (observing input voltage) could make some sense. Don't know if it would work and I think perhaps there is a problem with voltage needing to be higher than the battery. Maybe Victron have already thought of that and designed it out of their products. Been here before I seem to recall. 24v alternator is the thing.

It would be fun if a court had to decide what 'drop in' means. They might come to the conclusion it just means two items the same shape. 'Drop in replacement' Not 'drop in alternative'.

2 fires can be a solution for this. Lots of narrow Boats have two fires.

I seem to recall there are the remains of a miniature railway there for the gasworks.

Have they sold that many ? Warranty claims seem to not include burnt alternators. Also, as I have been saying all along, these things are great for solar panel use. I'm not remotely anti lithium batteries but I do question the drop in status. I guess a lot of these are sold to motorhome owners who are probably just a wee bit conservative and tie up their vans in nice safe camp sites with 6A mains supplies so they can charge their batteries up.

I know what it is supposed to mean but in reality most people can't 'drop' one of these in to replace an existing Lead battery. It won't work. Well I suppose it is possible/probable that more people have shore power than don't but in that situation one would not be looking to maximise battery efficiency anyway. Presumably if it all gets regulated at some stage then terms like 'drop in' won't cut the mustard. They might even turn into 'drop out' when the arrangement is rejected on safety grounds.

Yes but what does 'drop in' actually mean? It appears to be a meaningless term when it comes to batteries. A marketing term made up by someone at some stage. Was it Mr Sterling ?

Drop In is definitely an interesting but of terminology. Obviously this is referring to the size of the battery blocks as provided and it is convenient to supply LFP battery blocks which have the same 'form factor' as normal '110 leisure' type Lead batteries. But... If one were to take the term 'drop in' literally it implies that the battery blocks may be released from a height. In some cases this could be quite handy as getting down into the engine 'ole is arduous. I think the suppliers probably ought to have specs for how high one can drop the battery in from. Is it one metre or two? Perhaps 'drop in' is referring to a casual medical facility.

I have never run a main engine while moored in 30 yars of living on Boats. Always had a generator for charging when not moving. I disagree with using the main engine for this but when the Boat is moving taking advantage of the power available seems wise. More than half of that 30 yars was without shorepower although I admit one of the Boats has had the umbillical for a while. I hate it. and from beginning of April to coincide with the anniversary both Boats will again be off grid and free to roam. Yaay!

Oh maybe not then. Perhaps an inverter running off the AGM bank charged by the 175A Iskra alrernator powering a lithium specific charger. At the end of the day the issue is with inappropriate rotating electrics so perhaps this is where things need to change. I sometimes wonder about a permanent magnet alternator with a magnetic clutch. The best one would be running from the propshaft then you could pull some real power off it.