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Post by ComfortZone on Jun 18, 2023 12:07:42 GMT 12
I thought max output for a alternator was 14.6v That would be good, but my gear is 'special'. It doesn't want me to get bored so chucks in a few extra challenges. Tomorrow I'm going to work through all the tests in the Balmar manual. Will isolate the wiring harness, regulator and alternator. It's going to be like defusing a bomb. We need to check and isolate the red wire, blue wire and brown wire one at a time. If I can't find the fault in one of those, my batteries will blow up the next time I go fishing... PS, a standard 'dumb' alternator should give 14.4v all day, every day. So that is fairly much the same as 14.6v. With a regulated alternator, you can vary the voltage as per a programme. Our target bulk charging voltage is 14.8, absorption phase is 13.8 (I think) and a float type charge of 13.2 when the battery is full. If we really want to we can do an equalization voltage of 15.6v. But that is a deliberate overcharging, you have to watch the batteries and be careful, so we've never done it. Or so we thought. It appears it's been doing it all by itself... You have obviously got a short somewhere causing the fuse on the voltage sense wire to blow, there should not be any current beyond a few milliamps flowing. I would be looking very closely at where the -ve side feed to the regulator is coming from. You could run a pair of wires straight to the battery, with fuse of course, bypassing existing system to see if the regulator behaves itself By the way all alternators are "regulated" and can run up to 15.5 - 16V, your typical automotive alternator has an "internal" regulator, usually fitted to the back of it which controls the field current to drive the alternator's output. My big alternator is a large frame Leece-Neviille alternator (by Prestolite, who supply Balmar their stupidly painted "marine alternators" - you should never paint an alternator as it restricts heat dissipation) usually fitted to trucks/earthmoving equipment etc. It has the internal alternator bypassed with a field wire to connect to the supply from the smart regulator.
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Post by GO30 on Jun 18, 2023 17:28:05 GMT 12
Anything over 14.8V would be a concern I'd think. Even 14.4 maybe max.
On a my WR250F the battery died. No new lead available (they had just ran out, more were due) but got offered a lithium. Super duper light and a lot smaller but a shit load of balls. BUT a key when swapping is to check the vehicles charging system can do lithium. So far we have not confirmed that, even after the 3 dozen beers while trying. I need to start the bike a lot to get the battery down so the system can charge at full titty and I can check at what voltage it's doing.
But in the instructions it notes in bold - Any voltage over 14.8 is highly likely to cause the battery damage. Not that I know for sure but I'm pretty sure most leads are 13.8 to 14.4, 14.4 being easily the most common.
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Post by Fogg on Jun 18, 2023 17:48:37 GMT 12
My full River AGMs require 14.7v for Bulk charge at 25C ambient temp.
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Post by fish on Jun 18, 2023 21:53:29 GMT 12
The update is that I've fixed the fuse blowing problem, but have no idea how...
Regulator passed all the diagnostic tests. I then pulled every connection on the regulator and checked resistance of every wire. Then took the alternator off the engine and did the same. Nothing obvious.
I have confirmed everything works fine with the fuse in, and if I pull it out, batteries go to 15.6v, which happens to be the high voltage alarm setting in the regulator.
Our working theory is the fuse was blowing not because of a short, but because of a voltage differential. This should be caused by my dead batteries. The purpose of the voltage sensing lead is to correct for voltage drop in the high current cables from the alternator to the battery. Simple alternators sense the voltage at the alternator terminals. This can be as low as 0.5v under, meaning batteries are chronically under charged, especially in absorption time. Posh regulators sense voltage at the battery terminals, so as to ensure the correct charging regime at the battery, not what the alternator thinks the batteries are getting.
The batts are getting 15.6 because, when the alternator 'looses vision' of the battery voltage, it cranks the alternator voltage up in order to see a response in the battery voltage. If there sensing wire is down, nothing is seen until the alternator hits the 15.6v high voltage alarm.
The first fuse blew when the house bank was at 7v. The second fuse blew yesterday, I assume when I tried starting the engine with a flat start battery, before paralleling them. Today I paralleled to the house battery before starting the engine, i.e. no major voltage differential.
If my working theory is right, I will be able to re-create this by starting with a flat battery (or at least trying to) and hopefully blowing a fuse. Luckily fuses are only $1.50. This will confirm I'm across the issue properly, then all I need to do is shell out more $$$ and drop in a brand new start battery, to match my brand new house batteries and ensure there is no voltage differential at start up... mwahahaha.
On the parasitic load thing, it is possible that what we were seeing was the energy needed to energise the VSR (about 0.3 to 0.5 amp). This was opened by the little float solar panel on the start battery. Just tracking down that technical info to confirm.
Which would mean that, other than my dead batteries, there are no fundamental problems with the electrics on my boat. Just a bunch of circumstances coming together to fox me. All started by me leave the battery isolator on after coming back in the dark after a fruitless fishing mission, combined with house batteries near the end of their life at the time.
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Post by Cantab on Jun 19, 2023 6:57:40 GMT 12
I mentioned it before but it still worries me, is the output from the alternator going directly to the same battery set as the senses wire? If not, either one must be moved. Doesn't matter if you charge house or start first, then vsr takes over.
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Post by fish on Jun 19, 2023 10:07:31 GMT 12
I mentioned it before but it still worries me, is the output from the alternator going directly to the same battery set as the senses wire? If not, either one must be moved. Doesn't matter if you charge house or start first, then vsr takes over. My father and I are in the midst of a great debate on this very topic. The existing set up is the charge goes straight to the start battery, and when the VSR opens the house bank gets its bit. But the sense wire is on the house bank. Father wants to swap the VSR around, so the house bank is always on, and the start batt gets a bit once the house bank is full. There is a whole lot of logic about the house bank taking / needing much greater current, and a voltage drop across the VSR. My arguement is that you must always bias the start batt, so it is always charged. Esp if you start engine, up anchor, set sail and turn the engine off within 15 min. Unlikely the start batt wil get any charge in this scenario. The new Pb-C house batts can comfortably handle the starting current, so there is no harm in using them if the start batt doesn't get full, accept being AGM, if the start batt isn't fully charged, my old friend sulphation will come back onboard. But if we put the sense wire on the start batt, when the house bank is charging the regulator is completely blind to what is happening. It would fix it if we just had a battery splitter and both batts were open from the get go. BUT we've just installed a shiny new VSR... Do you think this could have anything to do with the current problem and fuse's blowing on the sense wire? Complicating factor in my head. The house bank is 300Ah and can accept up to 90a current (target 50a). The start batt is 70 Ah, while we can't find the spec sheet on this (Yuasa MS70), it should probably get between 7 and 10 amps. If the start batt gets the full ergs from the get go we are either over charging it, or we are relying on the internal resistance to limit its charge. We are currently undecided on what to do on this bit, but are focusing on determining the reason for the blown fuses and parasitic loads in the short term.
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Post by GO30 on Jun 19, 2023 11:26:42 GMT 12
My full River AGMs require 14.7v for Bulk charge at 25C ambient temp. Mine want to be charged at 28.8 to 29.4V then float at 27 to 27.6V. I have seen 29.4V on the screen but not often or for long, seems to hit that then quickly taper back and sit at 27.6V, it has quite a la de do da fancy controller. Note they are 12V Gels but set up in a 24V bank and full time connected to 1560W of solar panels that sit between 64 to79V. I have a temp sensor coming as they can do a LOT for battery longevity or so I'm told. I'm interested to see what difference that sensor makes.
Mr Fish, Tell Dad I'm voting on your side on the which charges first in Starting V House battery discussion. We can live without lights and charging for the phone but bugger all motors have crank start these days and I doubt he can push start the mighty Birdsal. While he may have something with the house often needed a big kick in the slats to get back to full charge, my understanding is the VSR allows for that.
Is your starting battery the same as the house batteries? Just thinking, based on no experience or decent knowledge but very well aware of how delicate electronic systems can be to even the tiniest of things, that in these days of more variability between batteries could that be playing with your charging system or VSR?
I'm still not that comfortable seeing over 15V though, that's way up there for a 12V system. Mind you if all can handle it, the batteries mainly, then maybe I'm being a bit paranoid.
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Post by Cantab on Jun 19, 2023 11:26:52 GMT 12
Like I said twice before, you must have the sense wire on the battery the alternator is charging. The vsr will sort the rest out, there is no voltage drop at the vsr. If you have diodes get rid of them, they confuse everything. I'll repeat, put the sense wire where the alternator feeds. If your not sure what I mean, I'll repeat it again. Put the sense wire on the battery where the alternator feed goes It makes no difference in reality which battery set that is.
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Post by fish on Jun 22, 2023 20:15:13 GMT 12
This saga is still rumbling along.
Today I determined that two windows are leaking, and I could poke a hacksaw blade through a gap I found. Very sub-optimal. Especially since I went to the boat to fix the regulator issue and spent the first hour or so determining the extent of welsh onions and plastering the window surrounds with my go-to black PVC tape...
The good news is I still can't get a fuse to blow. As Cantab has beaten into me, I can't have the sense wire behind an isolating device, so moved it from the house batt to the start batt.
AND, we've successfully determined why we didn't get a high voltage alarm when the regulator went to 15.6v. The lead from the appropriate terminal on the regulator does not actually go to the dash lamp!?! Amature hour...
But I have successfully gotten into the programming functions and documented the current programme settings, then changed the programme. What I found was the regulator is putting out about 0.3v more than the bulk set point. I.e. 14.8/14.9v instead of 14.6. I changed to a programme with a bulk set point of 14.1v, and the regulator and batts were all showing 14.5v. This appears to be the compensation limit. I'm yet to work out what a compensation limit is and what it means.
So making progress in that I'm increasing my understanding of the issues and doing a fair bit of learning, but haven't actually sorted everything so I'm confident I'm not going to cook my new batteries.
PS, looks like I need to start a separate thread on how to re-seat and seal windows...
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Post by jim on Jun 22, 2023 20:31:35 GMT 12
Hypothetically...(and not wanting to distract from your goal here) if you were building a new boat would you entertain two alternators , each with a completely independant and simple system for its battery. your house and start would never share problems and surely any fault finding would be dead easy. iv'e been thinking imagine having all this drama part way through a voyage...
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Post by fish on Jun 22, 2023 21:30:56 GMT 12
Hypothetically...(and not wanting to distract from your goal here) if you were building a new boat would you entertain two alternators , each with a completely independant and simple system for its battery. your house and start would never share problems and surely any fault finding would be dead easy. iv'e been thinking imagine having all this drama part way through a voyage... Well, this boat was built 40 years ago, and designed about 45 / 50 years ago, so having one alternator was the lap of luxury. Back when, if you had a house battery, it was used purely for lights, so you didn't have to light a parafin lamp. If I was offshore cruising, I'd definitely have back ups / redundancy for every system. But this is just a Gulf cruiser. What I was thinking about is if I had a catamaran, and I had two of these systems on each side to deal with. That would be double the cost from the get go... I'm not sure if I would go with two alternators, we don't have an issue with needing more power. And each alternator still ideally needs a regulator to optimise charging and manage the batteries. The only additional item we have is a VSR, which is loads cheaper than a second alternator. If I was designing a new system we would probably do one or two things differently. Probably use a charge splitter instead of a VSR. Certainly everything these days comes with blutooth and the ability to monitor, track, diagnose and programme from you phone. The big step up there would be the monitoring. Instead of one day finding my batts at 7v and having to fuck around with a multimeter for days, I'd get a message alert on my phone saying xyz is out of spec. This alarm has been triggered in this component, go and sort it. I have to accept this is a 40 yr old boat, we've owned it for 24 years ish. We've replaced the decks, painted the cabin and topsides, stripped the hull back, interprotected it, copper coated it twice, replaced the heads, installed a holding tank, replaced the motor, gearbox, drive shaft, stern gland / packing gland, rudder stock, rudder tube, rudder bearings, rebuilt the rudder, but never overhauled the electrical system and components. I'm probably very lucky its gone this long without a catastrophic electrical failure. And its in winter and not the week before Christmas. Seriously, that scenario crossed my mind... The boat used to have an engine driven compressor fridge, so the electrics were literally cabin lights, VHF and a compass light and nav lights. Then we added wind instruments. Then a chart plotter. Then an electric fridge compressor. Then an autopilot. Then a bigger hydrualic autopilot. Then the kids came along so now we've got a tablet, a laptop, and two phones. And now we have a mobile rural broadband unit that is on 24/7 when we are cruising. Oh, and a little inverter for charging all the various devices. Now I've added a diesel heater for winter cruising, that uses about 8watts as standard but bigger current draw on start up. We don't have a microwave, radar or a hair dryer, although I'm going to use the cabin heater as a hair dryer for miss 10yr olds hair. So you can see how in the time we've owned her, she's gone from an incredibly simple Gulf cruiser to a pimped and turbo'ed fully spec'd modern family cruiser.
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Post by jim on Jun 22, 2023 21:49:38 GMT 12
Fair enough - i can see the "evolution" there . looking forward to hearing its all sorted and team Fish are enjoying a balmy gulf cruise ...
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Post by fish on Jun 22, 2023 23:03:52 GMT 12
I believe I've worked out the compensation limit question. It is temperature compensation. Mid point is 25degC.
Ambient temp currently is about 15degC, i.e. 10 deg lower than mid point.
My new batteries have temperature compensation of 30mV/C. A random example Victron VRLA battery has 24mV/C. At 10 degrees cooler, the regulator is adding 0.3v / 0.24v to the target voltage to compensate for the cooler ambient temp. I expect that if I warmed up the temp probe to 35degC, the regulator would reduce the bulk charge voltage by 0.3v.
If this is correct, A. I can test it really easily by warming the temp probe, and B. my regulator is actually working properly and without any apparent issues.
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Post by fish on Jun 22, 2023 23:08:16 GMT 12
Fair enough - i can see the "evolution" there . looking forward to hearing its all sorted and team Fish are enjoying a balmy gulf cruise ... 'Balmy'? Just this evening I was warming the missus up to a family cruise over the July school holidays... Highly dependent on the diesel heater, which needs power to run, hence the focus on the battery issues. I think I've resolved the compensation voltage issue (its just temperature compensation). So now all I need to do is plug the high voltage alarm wire into the right spot (actually plug it into the dash light) and everything should be sorted. Will probably sit and watch everything closely while it goes through the first full charge regime, just to get some confidence, but I think I've turned the corner. Just need to fix the leaky windows now. I might invest in some more PVC tape to tide me over for a bit. White tape will be less visually obtrusive than the black tape...
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