Keajre

Thanks for the replies everyone really informative and useful. You guys are great

Thank you for clarifying ?

Dear friends, I’m in the process of selling a narrowboat . Can I ask is it necessary to register the sale with Maritime and Coast Guard agency? This is the first time I have sold a boat and I have no experience. I had issued a bill of sale which was a standard legal template from the Internet appropriate for water vessels. To me this seems sufficient and outlined various legal caveats such as no guarantee afforded and the boat is sold as seen etc. However the buyer is requesting we instead use of this : https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/763143/MSF_4705_Rev_1118_Bill_of_Sale.pdf They are also inexperienced, so just want to do the right thing for both of us. The boat is moored up on the Regents Canal in London with the appropriate CRT registration and license. The government advice about ships is that they have to be registered and a certificate issued, perhaps that’s more related to seagoing vessels, guessing here. I was just planning on informing CRT through their online service and assuming that will be sufficient. .Any advice would be extremely appreciated. Stuart

Hmm ye that would be slightly better, I suppose then at least the pump, fridge and lights would be powered by solar. Not a bad idea. Didnt think of that, will try it ?

Greeting Wonderful Boating Friends, I had a thought. I've had my 250w panel and MPPT for a few years now (with 600Ah of batteries and an inverter). It only usually gets used properly when I am continual cruising in the summer months. When I am connected up to ShoreLine power the panel isnt used since the MPPT detects the batteries are full. Anyone know of a device or a method so that you could switch seamlessly between Solar and ShoreLine power so as NOT to use any grid power unless solar was at capacity or beyond? Say for example you are drawing 300 watts. A usual scenario for me when working from home with laptop and monitor on. The inverter has to power these items (either inverting or pass through when connected to grid) since they are 240 (most of other items are 12v). Wouldn't it be great if say it was a sunny day, and the panel was capable of pulling in 200w, that ONLY the additional 100 watts would then be supplied by grid. Would reduce the electric bill and carbon footprint. I dont know of a way to do this without disconnecting shore on sunny days and inverting. That's a bit of a lame solution though for several reasons. Any thoughts?

Reduce capacity and voltage readings as the ionic process would stop earlier

Hahahaha

Getting back to basics though, the single battery in the bank of 4 thats showing a lower SG reading than the others actually has LESS electrolyte than the others in it, so on that basis alone the SG should be higher. So where is the sulphate? Must be on the plates right. Or as mentioned before, it wasn’t topped up with the correct amount of acid at the time of production. The load side negetive cable does connect to that battery, and I discovered yesterday that the crimp is faulty, the 70mm2 cable just slides freely inside the lug. In fact I removed it and re-inserted it freely. Need to re-crimp it when I get time. Can’t see how that would cause over gassing, arcing and the potential for a nice explosion during charging sure, but increased sulphurificaiton of the plates? Can’t see how.

Just when I thought I was starting to understand it, I watched this . . .

It’s because sulphuric acid is heavier than water, and in this case its 1.277 times heavier. Water is just two Hydrogen atoms and one Oxygen atom. Sulphuric acid is Sulphate (SO4) and Hydrogen (H). So the molecules of acid are heavier than then molecules of water. H2O vs H2SO4. That gravitational weight is being measured. Basically its almost 1/3 heavier. I think this doesnt answer your question. Why is it that concentration exactly? Not sure, I guess its just the net result of how much the two plates (lead and lead dioxide) can react between them before they become the same substance (lead sulphate when fully discharged). Nick Norman would probably have a more concise and correct answer. This thread has gotten me thinking too

Makes perfect sense now, thanks for bearing with me

So the sulphate comes from the added sulphuric acid

Starts out as lead on the neg plate and lead dioxide on positive plate. When discharged then positive plate becomes just lead and no reaction can take place between the two metals since they have become the same. so you say acid is added during production. What would happen if you fully charged a healthy battery, emptied the electrolyte, added distilled water and attempted to charge. Wouldnt the suphate from the plates mix with the oxygen and hydroden atoms to create more acid?

I think they just add distilled water and the sulfuric acid is created when a charge is applied. This thread made me finally dust off one of my lead acid books, which I bought with the best intentions over a year ago! In summary it says that lead Sulphate (PbSO4) forms on both plates and is broken into Pb and SO4. The water then disassociates with its 2 hydrogen atoms (H) and one oxygen atom (O). Then the Sulphate (SO4) combines with the Hydrogen (H) to form the Sulphuric acid (H2SO4). At the same time the Oxygen combines with lead to form lead dioxide (PbO2) I didn't realise that the acid 'quantity' remains the same, I guess because its formed based on the Pb and SO4 on the plates. So now makes sense to me why differing quantities of the electrolyte will change the concentration of acid. That being said, what happens if you drained the electrolyte and filled with just new distilled water. Would it have enough material on the plates to get back to the same amount of Sulphuric acid? I'm guessing it would . . . I have one of these for setting down from 12v to 5v, works incredibly well, and is very stable. Stepping up is much more complex than stepping down of course. I am going to try and trick my Victron into equalizing at 16.2v. Will revert

I always wondered. Assumed the sulphuric acid would reach the same amount eventually. So if it has a significant impact on SG readings, why doesnt it also have an impact on voltage? I have books I keep meaning to read about the deeper side of battery chemistry

Ah ok, makes sense, I’ll top them up and re-check after a couple of days, thanks I didnt know that. Thanks for sharing

It goes up to 1.30 sometimes afyer equalisation. Yes i did a calibration with distilled water. Not sure why the readings are so high. They are very new batteries

I’m using a refractometer instead of a hydrometer. So much easier, I’ll never go back

MPPT generates very little heat. yes I have the busbar covers, just need to adapt them and fit them. Been on my todo list for a while. This reminds me, thanks

I only took temp from one of the batteries at the time of sampling, was 28 degrees. So the compensation would be negligible. Although the lower battery was 2 degrees colder, so 26. Still would such a tiny compensation. Thanks for pulling out the part of the manual which relates to this. That’s good to know, 0.010 isn’t a concern then. I’m overreacting. Just wanted to check, spent a lot of money on the buggers, want to take care of them. That battery is furthest from the engine. Pic attached (its the battery behind the Blue MPPT regulator). Thanks for filling tips. I might try and trick the Victron Multi-Plus into delivering a correct equalisation charge and swap them around too, but no urgency it would seem.

Yes it was a poor attempt at humour ?

Hello Again, These figures aren’t temp compensated no. I just checked. The battery which reads lower is 2 degrees colder. It also has less electrolyte in the cell tank. Not sure how it’s possible to measure 3mm from below the well. Any tips? I’g Guess it was about 5-10 mm gap that battery (still well about the lead plates). The others are about 4-6 mm. I had no idea that difference would make such a difference. The thing is, 3 months ago I topped them all up. Tried to do the 3mm thing by eye back then. Again, that same battery is lower in electrolyte than the rest. My theory, two things. A) its gassing more that the others due to its position. b ) it’s gassing more because its connected to the negetive lead. Probably got that wrong, but cant think of any other reason why. All negs inc earth flow through that battery 1st. Coudl that cause it? Should I rotate them? Just the 1st and last battery? Good to know its not just me scratching my head on this one. I think with Victron MultiPlus I could temporarily increase the absorb voltage. The equalisation cycle just adds 1 volts (or similar). Not sure if it really matters., Like you say depends on the temperature I guess. The Victron is setup to temperature compensate when it charges (or draws) 32v, get them bubbling like a witches couldren lol

Dear Friends, Earlier in the year I installed four T145 Trojan wet lead acid batteries. Absolutely delighted with them. Once every three months or so I take a reading of the specific gravity. I have noticed for two readings in a row (over 6 months) that one of the four batteries in the bank has a specific gravity reading Of 0.010 less than the others. Three of the four batteries measure 1.290 when fully charged. The third reads 1.280 for all three cells (6v batteries). I was reading that if the discrepancy gets to 0.020 then the batteries become on unserviceable. I do conduct occasional equalisation charges although I never reach the recommended 16.2 Volts. Actually only manage about 15.2 which is under what Trojan recommend. Attached is the wiring diagram . Is the battery closest to the inverter that is reading less. SoC never goes below 70% (30% DoD). Little concerned and just wants to get some feedback from you guys Kind Regards Stuart

Happy to be corrected if I am wrong, I’ve already learnt tons from just this thread alone. Do really appreciate CanalWorld

Wonder how many molecules of steel I’m loosing each time I sound off the horn, I’ll think twice about using my horn :-D