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Electrical issues - please point me in the right direction.


MartinW

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4 hours ago, MartinW said:

My two domestic batteries are 185 amp/hours each so I wonder what size of onboard charger would be best for battery life. I am expecting to find one that has the recommmended desulphating charging mode to try and keep the old cells going as long as possible.

 

I started the motor to try and put some charge back in but as soon as I revved it up there was a new sound like a dry bearing so I stopped. The drive belts are both very worn and came loose after tensioning so I have ordered them up (and a spare set - it's the Boy Scout in me) Once they are installed I shall track down the bearing noise to an alternator or the water-pump. Meanwhile the Mikuni diesel pipe was fixed and it tried really hard to start but there is no fan noise so I have been recommended to have it sent off for a full check-over. In the course of my investigations I found a leaking elbow on one of the the Hep20 'circs' so have called it a day and gone in search of parts.

 

Sound like a dry bearing is probably belt  squeal becasue its slipping. Caused by the high load the discharged batteries are putting on the alternator. If you run it a little sower for half an hour it will probably rev up without any noise. New belts correctly tensioned are the way to go but if they are old and stretched I don't know why they stretched again so fast.

 

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Thanks for the reassurance Tony, there were almost no teeth left on the belts compared to a new one (The yard had every size except the one we needed) I am philosophical about things that prove to be broken as at least I know it's right once it's fixed.

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9 minutes ago, Tony Brooks said:

 

Sound like a dry bearing is probably belt  squeal becasue its slipping. Caused by the high load the discharged batteries are putting on the alternator. If you run it a little sower for half an hour it will probably rev up without any noise. New belts correctly tensioned are the way to go but if they are old and stretched I don't know why they stretched again so fast.

 

Worn out alternator pulley letting the belt bottom in the groove?

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Maybe. One belt was so stretched that the alternator was hitting its neighbour at the end of adjustment and still slack. Much of this is down to lack of use, I think, it's just like restoring any old piece of machinery.

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FWIW the "teeth" are not there for the reasons teeth are usually used on drive systems. They are there to allow the belt to bend around a smaller pulley yet still transmit enough power. All V belts drive by friction between the pulley and belt SIDES - hence @Tracy D'arth mentioning making sure the belt is not sitting on the bottom of the pulley groove.

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I'll check that when I get back out there. Jonathan the Technician has spare keys so he will fit the new belts when they arrive. Thanks, Tony, knowing how things actually work helps explain why they don't, I am much more used to chains and flat, toothed belts. I did once drive a car with a Variomatic transmission, though, so I ought to have realised.

 

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Drive belts replaced and no longer squealing. The pulleys do not look thin or otherwise worn except polished by slipping belt. Both alternators are charging. Batteries showed 12.3 volts at rest after 1 hour engine run previous day and 4 hours of using a 4amp charger on the generator, so obviously need replacement I guess, however I have also ordered a 30 amp Victron charger so that I can try the desulphating charge first. Once I get move the day's cruise to the mooring with shore power things will be easier but I need to wait for the Mikuni to come back from repair and  re-fit it. Onward, ever upward!

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1 minute ago, MartinW said:

Drive belts replaced and no longer squealing. The pulleys do not look thin or otherwise worn except polished by slipping belt. Both alternators are charging. Batteries showed 12.3 volts at rest after 1 hour engine run previous day and 4 hours of using a 4amp charger on the generator, so obviously need replacement I guess, however I have also ordered a 30 amp Victron charger so that I can try the desulphating charge first. Once I get move the day's cruise to the mooring with shore power things will be easier but I need to wait for the Mikuni to come back from repair and  re-fit it. Onward, ever upward!

4 hours at 4 amp will put 16Ah into the batteries. an hours running the engine wont do much better. running all afternoon and see what happens, what is the maximum voltage you are seeing while charging

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3 minutes ago, MartinW said:

Drive belts replaced and no longer squealing. The pulleys do not look thin or otherwise worn except polished by slipping belt. Both alternators are charging. Batteries showed 12.3 volts at rest after 1 hour engine run previous day and 4 hours of using a 4amp charger on the generator, so obviously need replacement I guess, however I have also ordered a 30 amp Victron charger so that I can try the desulphating charge first. Once I get move the day's cruise to the mooring with shore power things will be easier but I need to wait for the Mikuni to come back from repair and  re-fit it. Onward, ever upward!

 

You should not conclude that unless you were monitoring the  amps. It is likely to take 12 hours or more to fully recharge the batteries and you have got to approaching a true half charged in 5 hours with 4 being on a very low poser charger. I think on that charger you need well over 24 hours and probably more.

 

It might turn out that the batteries are poorly but I would not condemn them and spend money before proving them to be so.

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Yes, I'm in no hurry to try and lift them out just yet as they are so heavy I reckon I would have to move some ballast to balance-out their loss. As in the set-up as it was the engine was the only way of charging them I will fit the charger when it arrives and run the generator when ever I am over at the boat until I can get to move it to the shoreline mooring. 

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41 minutes ago, MartinW said:

Yes, I'm in no hurry to try and lift them out just yet as they are so heavy I reckon I would have to move some ballast to balance-out their loss. As in the set-up as it was the engine was the only way of charging them I will fit the charger when it arrives and run the generator when ever I am over at the boat until I can get to move it to the shoreline mooring. 

 

There is something I don't understand. You run the engine for an hour and then swap to  a generator so you are still creating noise.  Why did you not run the engine for the five hours? The charger you say delivers a maximum of 4 amps while the engine is likely to have a 50 amp or higher alternator. Seems like a no-brainer to me with such flat batteries. Neither the alternator nor the charger will deliver their maximum output for long but typically over 3 hours or s a 50 amp alternator will average 25 amps.

 

You may believe running the engine for battery charging will damage it and it may well do if you insist on running it at idle for hours on end, but that is a stupid way of battery charging. Now please understand that a typical narrowboat on a canal demands a maximum of 6 hp from the engine but more likely only 2 to 4 hp. An alternator charging batteries discharged like yours is likely to demand well over 2 hp from the engine so not much less load than while cruising canals.  So you need to set the engine revs in neutral to those that deliver maximum charge and then gradually reduce them as the charging current falls to maintain it at the maximum charge the alternator will deliver. However, I don't think you have an ammeter fitted so with a typical engine (not air cooled Listers) set the revs to about 1200 rpm and keep them there for several hours. If you have an engine heated calorifier this will also heat the eater in the shortest time.

  • Greenie 2
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I started to following the advice of running the engine at 1200 rpm but that is when the belts started squealing so I stopped and reverted to the gennie. After the belts were replaced the techie ran the motor for about an hour (I think, but not sure of the revs, I wasn't there) just to check all was ok. So far as the belts were concerned it was, but the rev-counter has stopped working and the voltmeter is doing a strange dance around the 11volt mark so I stopped until the charger arrives and the Mikuni is re-fitted (removing it involved some unplugging so I want to put all that back). I am trying to follow your advice as best I can but I imagine it is quite frustrating for you to be trying to help at distance as if  down a tube in the dark. It certainly feels that way to me as I squash myself around the engine and under the decking just to get at these bits. How I muttered working under car-bonnets (except Triumph Heralds and the like) and now wish for a that level of access. Thanks again, Martin

 

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1 hour ago, MartinW said:

I started to following the advice of running the engine at 1200 rpm but that is when the belts started squealing so I stopped and reverted to the gennie. After the belts were replaced the techie ran the motor for about an hour (I think, but not sure of the revs, I wasn't there) just to check all was ok. So far as the belts were concerned it was, but the rev-counter has stopped working and the voltmeter is doing a strange dance around the 11volt mark so I stopped until the charger arrives and the Mikuni is re-fitted (removing it involved some unplugging so I want to put all that back). I am trying to follow your advice as best I can but I imagine it is quite frustrating for you to be trying to help at distance as if  down a tube in the dark. It certainly feels that way to me as I squash myself around the engine and under the decking just to get at these bits. How I muttered working under car-bonnets (except Triumph Heralds and the like) and now wish for a that level of access. Thanks again, Martin

 

 

Check the connections on the alternator(s). It should not affect the voltmeter but a loose connection on the W (rev counter pulse feed) will cause the rev counter to jump about. If all seem firm and tight, including where the cable is crimped into the terminal. The engineer may have displaced/loosened one. I fear the alternator may be playing up, especially if it only shows 11 volts. Even with really discharged batteries the alternator should produce over 12 volts within a few minutes of starting and running a some speed. It suggests that a diode might be playing up. It will still charge but only have about 2/3 of its output and the charging voltage will be lower that it otherwise would be at that state of  battery charge.

 

It is hard trying to help at a distance but well worth the effort when a problem is solved, especially if it saves a fellow boater some money. You seem to be doing well by explaining what you are doing and why you want to do it. Its the people who ask for help and then don't reply, refuse to explain why they think their diagnosis is a good one and want to argue the case that really wind me up. The number of time myself and others ask for photos and get ignored are too many for my liking.  Asking for further explanation is very different from arguing.

 

 

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38 minutes ago, Tony Brooks said:

 

You seem to be doing well by explaining what you are doing and why you want to do it. Its the people who ask for help and then don't reply, refuse to explain why they think their diagnosis is a good one and want to argue the case that really wind me up. The number of time myself and others ask for photos and get ignored are too many for my liking.  Asking for further explanation is very different from arguing.

 

 

Yes, I agree. Martin is doing a good job of describing his issue. As you are on top of this Tony, I will remain in the background and introduce fish jokes at an opportune time.

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10 hours ago, MartinW said:

, but the rev-counter has stopped working and the voltmeter is doing a strange dance around the 11volt mark

 

Have had this issue when one of the belts on my Lister 4 pot engine was slipping due to high alternator load / slack belt combination.

Might be work another check of the belt tension / pully condition.

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My 30Amp Victron charger has arrived today so my next job is to buy the correct cable for connecting it to my 2 185Amp hour boat anchors leisure batteries. I assume (at the risk of being presumptive) that I should have pre-tinned marine cable although this is not a salt-water environment? The batteries will be about 3metres away from the mounting-point in the cupboard where the 240v trip-box and inverter etc are. I am again assuming that 10mm squared conductor cable is the stuff to have. (the unit can accommodate up to 13mm squared) Looking at the present set -up the earth post on the nearest battery is looking crowded as the nut has no spare thread. What would be the best solution and as I cannot get across to measure due to the snow, If I am ordering up crimp ends for the cables, what size fixing-hole do I get? (How long is a piece of string, etc - I just wondered if there was a 'normal' or 'standard' size)

battery bank1resized 50.jpg

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6 minutes ago, MartinW said:

My 30Amp Victron charger has arrived today so my next job is to buy the correct cable for connecting it to my 2 185Amp hour boat anchors leisure batteries. I assume (at the risk of being presumptive) that I should have pre-tinned marine cable although this is not a salt-water environment? The batteries will be about 3metres away from the mounting-point in the cupboard where the 240v trip-box and inverter etc are. I am again assuming that 10mm squared conductor cable is the stuff to have. (the unit can accommodate up to 13mm squared) Looking at the present set -up the earth post on the nearest battery is looking crowded as the nut has no spare thread. What would be the best solution and as I cannot get across to measure due to the snow, If I am ordering up crimp ends for the cables, what size fixing-hole do I get? (How long is a piece of string, etc - I just wondered if there was a 'normal' or 'standard' size)

battery bank1resized 50.jpg

 

 

 

The electrical regulations say you should not have more than 4 wires connecting to any stud so you are already way above that.

 

Take the opportunity to wire up your batteries correctly - use a Bus-bar and run a single wire from the battery to the bus-bar and then take your connections of that.

 

1) You don't need tinned copper cable.

2) Yes 10mm will be sufficient

3) Studs are generally 8mm

Edited by Alan de Enfield
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You could for ease and for now just connect it to the inverter cables but they should have a master switch so eventually you need to  wire it another way. If the master switches are in the positive you can keep the negative on the inverter. The positive could run to the BATTERY side of the domestic master switch.

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On 06/02/2021 at 12:26, MartinW said:

Yes, I'm in no hurry to try and lift them out just yet as they are so heavy I reckon I would have to move some ballast to balance-out their loss.

err   ...............   won't you have to replace them with something (presumably batteries) of a similar weight?

 

Edited by Murflynn
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5 minutes ago, Murflynn said:

err   ...............   won't you have to replace them with something (presumably batteries) of a similar weight?

 

Haha, all the fit-out of my boat is on the port-side so I pictured it tipping over that way as the batteries came out over the portside, pushing the basin waste outlet (only 100mm above the waterline at the moment) under the water and highlighting the current lack of a functioning bilge-pump. It's things like that that keep me wake at night!

 

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