dmr

This last year Iv had 6 (675Ah) Trojans rather than the previous 4 so have thought about this stuff a little bit. (tangent, one of the originals died after 3 years of hard use so I got 4 new ones and kept two old ones, wired as a slightly unbalanced a split-able bank) There are three advantages 1 In normal "boating every day mode" the bank is at a higher SoC so should last longer. 2 In winter move once per week mode with a bit of care I can manage with running the engine only every other day. 3 It looks really cool! I did think that charging the bank from a less discharged state would be slower (more time in absorption) but I don't think this is the case. Gibbo had a rule (I think) that the current into a battery (in amps) is roughly equal to the amp-hours required to get to fully charged, so in fact it all balances out.. Only real issue is that when we get down to 50% or even less it takes a LOT of charging, lots of time in bulk mode. Could do with a bigger alternator but would hit all sorts of belt and pulley expenses. ...............Dave

The plot thickens Maybe it went to Middlewich and then back to Brum? Maybe they have made several of these boats? or just maybe EasternEuropeanLadies fears were correct.... a competitor has seen her lovely boat, taken photos, and started to mass produce replicas? Sadly Gillie was walking the dog and had the camera with her when it went past so I was not able to take a photo ..............Dave

Thanks. I remember the previous thread but did not remember it coming to such a firm conclusion, maybe I missed the last few posts. I sometimes get a bit distracted by the need to go boating! ............Dave

I forgot to say...... Concerning the precious boat for sale (with that very unusual and potentially dangerous pointy front) It, or something very very similar, passed us in Middlewich earlier this year (June ish) It looked to have brand new owners who were taking a lot of care as they had many large plastic fenders down each side. .............Dave

Interesting, thanks, had not read that document before. It might or might not be true of course.. So, We are now saying that Peukert only applies if we discharge a battery continuously down to flat...ie it is just a manifestation of a specific test procedure that is unrealistic for many/most boaters. I assume the mechanism of this is mostly just the usual surface effect (plus a bit of volt drop on internal resistance). Its rather like the old days when you cranked your battery flat trying to start your car (mini) in the winter. Went back to bed for an hour and then tried again when the battery had come back to life! You don't of course need to run your Trojans to flat to confirm this, just make a LOT of cups of tea then continue to discharge at lower rate down to about 50% then see how smartgage and amp hours compare (and maybe check specific gravity). I can't do this because...... 1 Our kettle runs on gas 2 I don't have an amp hour counter. I do have a pile of electronic bits on the table in front of me right now so might have an amp hour counter in the next few months! ...............Dave

very nice and very interesting! ............Dave

So, if I understand what you are saying, you believe that 1 The Peukert effect does not really exist and is just an aberration because Peukert measured his effect by discharging a battery right down to empty at a high current? and hence 2 If we take out a high current for a short time then leave the battery for a while it will "recover its capacity" as if the Peukert effect did not exist? If you answer yes then. 1 Is this just a sweeping statement that you sometimes make (you confessed to this earlier) ? or 2 Have you used your Smartgage and AmpHour counter to investigate this? (only curious as this stuff is on my ever increasing list of things to do) ..................Dave ...........Dave

I'm going to argue with Nick, its more intellectually satisfying in you post 104 you say......... ======== But it was your statement in post #88 that was wrong. If you take 100A for 10 mins, you lose 16.6AH from SoC, not the 32 you mentioned. Kirchov et al says that current around a circuit is preserved, it cannot disappear into the ether! ========= (I must learn how to do selective quoting) I don't agree, (or maybe we are just not quite on the same wavelength here) but I don't get where Kirchov fits into this. If you take your 16.6 Ah out of a battery bank (that has say 400Ah capacity and is fully charged) the Mr Peukert would say that you have in effect removed 32Ah (or whatever) so there really is only 368Ah left. Nowt to do with Kirchov just that some capacity has somehow vanished. So the real arguments are 1 Do we even believe Peukert? 2 Where do those lost Ah of capacity go to? .................Dave

You really are totally wrong here. 50% is just an arbitrary point on a continuous curve (not a straight line) of discharge vs cycle.life. I think you should think more carefully before making such strong and definitive statements on a public forum as you can end up looking a bit silly.. There are a fair few folk on this forum who know a lot about batteries, both theory and hands on. If you don't really understand batteries and electricity then ask questions and hopefully these good folk will answer them. .............Dave

I strongly advise you not to argue with Nick about his ability to measure his battery capacity! If you really believe that taking bursts of 200 amps out of a (Trojan) battery bank is destructive then Nick does have a problem, but of more concern is that many many other boaters also have a similar problem. Barrus and Beta routinely fit 175 amp alternators and so when the engine is first started the charge current will be close to 175 amps for quite a while, or do you think that high charge currents are less destructive than high discharge currents? I probably agree with your earlier remark that ideally batteries should only be discharged by about 20%, but this does fly in the face of the almost biblical 50% rule so you need to be prepared to come up with a good argument to justify this. ...............Dave. r

Just tried to get some prices off the www and it appears that it is indeed much much cheaper to send a parcel from Chna to the UK than to send an equivalent parcel from somewhere in the UK to somewhere else in the UK. Its all a bit complicated and involves exchange rates etc but it looks to me like £1.50 to £2 is the cost of China to UK postage for a small parcel. ...............Dave

Yes, I also have purchased quite a few very low value electronic components from China which must have been posted individually rather than by the container, and the total cost was less than internal uk postage cost. I have a horrible feeling that some unfortunate postal deal is resulting in British companies subsidising their Chinese competitors. Another possibility is that the Chinese state is subsidising the Chinese companies to work at a loss (it likely has some share of the ownership of some of them) to help them build up long term international business. ..............Dave

Yes, I just picked one at random from eBay to illustrate what I was talking about. We started with an eBay cheapo and it didn't last very long or work too well. Have since found some much better higher current Apple compatible devices that have worked hard and well for the last year. Rather more expensive too! Think they were branded as "Scosche" and cost about £12, two outputs at 2.4 amps. .................Dave

I reckon it means 2.1 amps, don't think you would get 21 amps thru those little pins inside a USB plug. ..............Dave

The more flexible alternative is to just insert a little USB adaptor into a standard 12v socket, somat like this: http://www.ebay.co.uk/itm/New-Black-USB-12v-5V-1Amp-to-12-Volt-Car-Charger-iPhone-Samsung-HTC-Blackberry-/281826810608?hash=item419e2fdaf0:g:n4IAAOxyThVTb29Z You can also get double and high current versions, and some will even work proper with apple ipads and stuff. Not 100% sure how all this Apple (and possibly Samsung) stuff works.but I think the chargers (and Macs) hold a USB data line at some fixed voltage so the ipad/iphone can recognise when its plugged into an Apple charging device. ............Dave

Caulking to float first time is not a good idea. Neither is the emergency measure of sliding a box of ash over the outside to suck ash into the gaps. When the timber gets suitably wet it should expand to its correct size with no gaps. If you fill the gaps first then when the wood expands some very big stresses will be created. Well that's what I was told by a man who knows these things, and after a week or so the boat did become watertight just like he said it would! ............Dave

Have you been down Hanwell and into Brentford of late?. We did it a couple of weeks back and prior to that it was about 4 years ago. A bit of a transformation has taken place, probably from a lot of volunteer input. Hanwell was almost 100% free of litter and graffiti, and the water was mostly water, not that black treacle stuff we met on our last trip. Zero weedhatch adventures too.. Brentford itself felt a lot better too, and a good drinking pub. ..............Dave

Most likely not good. The higher spec generally indicates an increased amount of additives and in a lightly loaded diesel engine (like in a boat) these can contribute to bore glazing (a serious problem). For this reason many specialist oil companies (and even Halfords) still make a CC oil available. This should be fine but check with Barrus,to be sure. .............Dave

What you meant to say is that Beta are going to be selling someone else's oil with a Beta label on the pot! .............Dave

We have just arrived at the Eastern end of the K&A and plan to stay here for a while, but if the bar is going through a bad patch after Christmas then let me know and I will come and help out with the beer drinking. ............Dave

We did it the other way a couple of weeks back. Phoned CaRT a couple of days beforehand and got ansafone. Got a call from CaRT about 6pm the same evening to confirm and apologise for not phoning back sooner. So.....if CaRT have not phoned you back to confirm then I would NOT go through Teddington. CaRT lock keeper turned up well in advance of our requested time, and phoned Teddington for us as we left., well done CaRT .....................Dave

I reckon you can safely parallel a 110 and a 200Ah as long as they are the same type of battery (don't mix conventional and AGM etc). Proper leisure batts have thick plates to cope with deep discharge. Proper starter batts have more thin plates to deliver the high start current but might fail after only a few deep discharges. However it all gets a bit uncertain as some batteries are allegedly "dual purpose" and some people say real proper truck batteries have thicker plates than bog standard batteries. I suspect all sorts of batteries get all sorts of labels stuck on them, who knows what is actually inside. You could just try it and see..Danger is that if the starter battery has a big failure (shorted cell) it could harm the other good batteries. ..............Dave

24volt system has two 12v batteries in Series...this is the only time that its actually true that the capacity of the new battery will be dragged down to that of the old battery. ..............Dave

Most rivers are navigable easily most of the time, even with a small engine. Most rivers are unnavigable from time to time regardless of engine size. So, if your engine is a bit small there will be a few more days each when you would choose not to go onto the river. Its probably not a big deal. .............Dave

And if your moored on a river where there is any possibility of the locals letting you loose overnight then a discrete mud weight over the upstream end is an extra bit of security.. .............Dave