Jump to content

Battery wiring at fault? 12v socket reading jumping.


Lady_Why

Featured Posts

2 minutes ago, Lady_Why said:

No, I don't have an ammeter unless it is very secretly located - if I had any form of wall-mounted measures about I would make sure I knew what they are for! Multi-meter is all I've got.

 

I think it is worth exploring this thing you describe as a shunt. Shunts are for ammeters. If you have a shunt, your boat almost certainly has (or had) an ammeter of some type or another. Does it have two little this wires attached to it disappearing off somewhere? 

 

Could you post up a photo of it?

 

 

  • Greenie 1
Link to comment
Share on other sites

Not wishing to mansplain (which my wife accuses me of) I will just say this.

 A battery charges when the voltage is higher than the battery voltage, and from your measurements you should be charging.  You only real know when the batteries are charged by measuring the charge current going into the batteries which should have fallen to about 1 amp per battery in your bank - that depends upon battery type, size etc.  Then when you stop charging you use the battery power up.  If the batteries then go flat faster than you think they should then either you are using power too quickly (possibly something left on that should be off) or your battery bank is too small for your lifestyle or the batteries have lost all their capacity.  Without being able to measure the discharge current it’s difficult to know.

  • Greenie 1
Link to comment
Share on other sites

1 hour ago, Lady_Why said:

I am currently on the 12v group on FB about this problem but I thought I'd also ask here.

Maybe a little 'history' may help :

 

Is the boat new to you ?

Do you have an immersion heater ?

Do you have solar panels ? (how many, what size ?)

Have you boated thru' an Autumn / Winter period before ?

How long would you normally run your engines ? (4-6 hours is not that unreasonable - particularly if only at tickover and not actually cruising)

What electrical appliances do you have on board ?

Have you done an electrical audit ?

Why did you decide to have 4 leisure batteries ? (having more batteries does not mean you can run the engine for shorter periods)

 

It is quite easy to 'kill' a set of batteries in a month by repeatedly undercharging.

Edited by Alan de Enfield
  • Greenie 1
Link to comment
Share on other sites

Probably not relevant to the posted problem but it calls into question the accuracy of the diagram somewhat. The battery charger seems to be connected as normal to Domestic bank positive but the negative seems to go to the engine battery positive. I don't see how it can work.

 

13.4V charge at start up suggests to me a high charging current so the batteries may well be very flat but if the voltage eventually reaches 14.1 I doubt its an alternator fault.

 

Were the batteries ever properly charged? Has the OP charged them at 1200 rpm plus for 12 hours?

 

Could a battery be faulty with an internal short? Get them as fully charged as you can and the disconnect them all from each other, leaving just one to supply the minimal electrical load. Measure the voltage of each. Next morning remeasure all but the battery that is in use. They should all show more or less the same voltage. If one is low then its probably has an internal short. Reconnect and charge, take the one that was supplying the boat  and repeat on that battery. If there is an internal short or even a poor bit of lead burning on the groups and interlinks you can get all sorts of random fluctuations as the circuit makes and breaks.

 

Photos of these boxes etc. would be helpful.

 

 

 

  • Greenie 1
Link to comment
Share on other sites

16 minutes ago, Tony Brooks said:

Probably not relevant to the posted problem but it calls into question the accuracy of the diagram somewhat. The battery charger seems to be connected as normal to Domestic bank positive but the negative seems to go to the engine battery positive. I don't see how it can work.

Not only that, but, assuming red wires are positive, it would appear that the feed from the alternator is connected to the negative side of the batteries ?

 

I think the wiring diagram should be discounted.

Edited by Alan de Enfield
Link to comment
Share on other sites

Lady-Why.

 

Is this a boat you have just purchased, you seem to having a lot of problems and questions - have you (for example) resolved your need for a survey for insurance purposes ?

 

Did you have a survey when you purchased it ?

If so did the surveyor highlight any of these problems, or suggest solutions ?

If so did he do a Hull survey, sufficient to satisfy your insurers ?

 

Link to comment
Share on other sites

1 hour ago, Chewbacka said:

Hope my gut feeling that your batteries are shot is wrong.

When you do work out what’s going on and fix it, please come back and tell us, very interested.  

 

This seems unlikely given the batts are only ten days old. 

 

More likely I'd say, is the old batts suffered from chronic undercharging and eventually expired, and assuming the batteries dying was the only problem, Lady Why bought a new set. A perfectly reasonable thing to do but unfortunately this only addresses the symptom, not the cause of the problem. (Most of us have done this at least once!) 

 

So a set of new and well charged batts probably worked well for several days until beginning to succumb to the low charging voltage that killed the previous set. Now the root problem has resurfaced and if fixed pronto, the new battery may survive without too much degradation. On the other hand, my gut feeling is also that Lady Why is at the base of a long and expensive learning curve as few 'marine electricians' truly understand batteries for liveaboards either, so getting good competent advice from a tradesman is going to be difficult. 

 

Even sorting knowledgeable advice in this thread from the chaff is difficult, so I fear the worst for her. Learning to generate and store one's electricity is easily the most challenging and expensive part of being a full time, off grid liveaboard.

Edited by Mike the Boilerman
  • Greenie 3
Link to comment
Share on other sites

Back at the cafe and on the web - bear with me as I address all your input! And thanks for continued effort to help me. Mansplaining wasn't needed, but I wasn't offended: since I am 'learning as I go along' there is no way anyone can gauge my knowledge level (it's currently more practical than in depth). 

Firstly: I've solved the jumpy reading at the 12v socket. I found that one of the cables to the inverter had been pulled loose and fixed it. My charge still reads higher at the 12v socket than it does at the battery bank though, which confounds me. 

Secondly: I would guess any ingoing charge is a good thing! I'm also guessing having a bank of 4 leisures (it's always had 4 so I've kept that up) and an alternator that doesn't go above 13.40 (revving & regular checking makes no difference) may explain the slowness in charging. I will contact the R&N forum to find out if that is normal for a vintage engine or whether the alternator is getting knackered. Meanwhile I will get the genny going for a full 10hr charge tomorrow (had to source the correct oil for it first). 

My boat isn't a new purchase (I've had her 10 years!) but I've spent most of it in a marina (on mains) until the fees forced me out. So I am now learning the 'real thing' so to speak. Which I dont' mind... except for the current stress. My questions regarding a survey on the other thread was because an insurance survey was new to me (my boat just turned 31); I did a valuation survey before the purchase 10 years ago. That is all sorted now though.

My boat has no solar panels (yet) and no fancy gadgets  - it really is just the lights, the water pump and the very-turned-off fridge. The only immersion heater is sealed in the calorifier. Neither do I have any solar panels (yet). Although I top up the starter with a small clip on one.

The shunt does look indeed like a shunt! But since I'm away from the boat I'll have to go back and see if there are any mystery wires leading to some mysteriously hidden ammeter (it really would have to be very cleverly hidden, so don't hold your breaths!). 

I realised however that I may have something that is a boat perk: a switchboard for all my loads (e.g. lights etc). I assume these are reliable and that I could check how the batteries discharge without any load on them by switching all off. And then I can exclude a mystery load, yes? Unless there are some sneaky ways a load can bypass...

So... my current plan is:

1. Get the genny going for 10hrs tomorrow.
2. After 10hrs, measure with multi-meter and then switch all switches on the board to remove load overnight. Disconnecting them sounds like a good idea too (thanks, Tony!)
3. Measure again in the morning to deduce if the drop is the same (in which case I may indeed have shot my batteries...) (unless sneaky bypassing load)
4. I've also remembered seeing a hydrometer, which I believe test for sulfation (yes?). I've found a dodgy youtube video to guide me. Well, I hope it guides me.

I am, of course, hoping here that the inverter cable caused the drop somehow, but I can't see how. 

Link to comment
Share on other sites

...I am little offended though at the rampant distrust of my diagram! - and yes, I also reacted, when checking and drawing, that there seemed to be a negative going to the battery charger from the starter's positive (I'd never really looked closer before as the set up was done by someone supposedly reputable & I trusted it). I am not at a confidence level of changing things around thought. Photos added to silence the doubters. ?

I should add these are old pics; the terminals are properly cleaned up currently.

 

2 old battery set up.JPG

1 old battery set up.JPG

9 minutes ago, WotEver said:

Sorry if I missed it, but presumably you’ll be powering a mains charger with the genny? What charger is it?

Got this one. First one I've had so will be learning it tomorrow. https://www.screwfix.com/p/impax-im800i-700w-inverter-generator-230v/15760 - and yes, planning to plug it in my mains plug so it goes via the battery.

Edited by Lady_Why
Link to comment
Share on other sites

33 minutes ago, Lady_Why said:

Got this one. First one I've had so will be learning it tomorrow. https://www.screwfix.com/p/impax-im800i-700w-inverter-generator-230v/15760 - and yes, planning to plug it in my mains plug so it goes via the battery.

WAIT WAIT

 

What size is your battery charger (Amps)

That generator will only power a small battery charger - depending on make / quality) as some battery chargers are very inefficient.

You may well have problems if your charger is much above 20 amps.

 

I note you mention an RN engine, is this is a slow-thumper (what revs are tick-over)

What is the pulley ration between your alternator and your engine ?

An alternator at maximum is looking for about 6,000 RPM but they normally work OK'ish on boats at 3-4,000 so a boat engine at 1200 RPM and a 3:1 pulley ration will be turning the alternator at 3,600RPM

 

If your engine tickover is (say) 400RPM and you have a 3:1 pulley ratio your alternator will be turning at 1200rpm - which could account for some of your low charging 'numbers'

 

So questions for you :

 

Is the 700w genny rated at a continuous 700w, or a maximum / peak 700w ?

What size is your battery charger ?

What is you engine tick over sped ?

What is your engine to alternator pulley ratios ?

 

Edit - Found it : the generator is 780w MAX/ Peak & continuous is quoted as 700 watts

Edited by Alan de Enfield
  • Greenie 2
Link to comment
Share on other sites

Be aware that the 12V so called battery charging output is of very low current and is probably virtually unregulated so providing the  generator is powerful enough to drive the charger use the mains output to power the charger.

 

FWIW. I would expect the battery charger to have comparatively thin wires on its output, similar to the thin red one in the photo but I can't see a similar black one but that one might e connected to the actual engine or main negative busbar (as long as the masters witch is in the positive side).  Typically I would expect the thicker cable on the engine battery positive and the simmilar sized on on the negative of the domestics to be a pair BUT we still have no photo of the "box" beside the battery charger. There is a lot we do not understand at the moment.

 

As far as I know NO alternator charges a well charged battery at 13.4 volts. This includes the very old Lucas 10 and 11 AC. Even those reached 13.8 to 14.2 volts so if you still get13.4 volts with a well charged battery bank it looks like a faulty alternator. Probably a diode  has failed inside it. A photo of the alternator will help so we can advise if it worth trying to get it tested or if a new one may be a better option.

 

edited to add. I agree with Alan about low engine & alternator revs.

Edited by Tony Brooks
  • Greenie 1
Link to comment
Share on other sites

10 minutes ago, Tony Brooks said:

Be aware that the 12V so called battery charging output is of very low current and is probably virtually unregulated so providing the  generator is powerful enough to drive the charger use the mains output to power the charger.

I know, like me, you are a little "sceptical" of product reviews.

 

One of the reviewers of this generator quotes :

 

I had a power cut for a whole day and needed to keep my home-office on line (computers/iphone/4G). This was ideal to keep everything running for a day and also had output to power the fridge and the freezer too ! "

 

(Amazing from a 700w genny).

Edited by Alan de Enfield
Link to comment
Share on other sites

Alan - Right, now you definitely have me at the novice end of things!

I only know that my engine is a RN DM3 - I have no clue what the rpm/revs are at tick over but the indicator lights don't turn off unless I rev it past tick over (which I've been told is one indicator that nothing is charging as of yet). I have no clue how to find out the pulley ration either (unless it is in the manual somewhere?). She very much feels like a slow thumper though. 

I had no clue there may be an issue between the battery charger/genny  (the electrician who advised me to plug it into the mains didn't mention it) - so thanks for bringing that up! I'm in the cafe currently, but I believe this is the charger I've got: https://www.batterymegastore.co.uk/sterlingpower-ab2480.html

I am guessing that the 'charge current' (A) is the amps... in which case it is 80.

Should I charge directly with clamps then? It doesn't seem the alternator can do the job, so genny is my nearest solution currently as far as charging up goes (yet to determine reason for depletion). Without that, I'll be pretty lost what to do.


Tony - the thin wires up to my battery-charger are actually intertwined red and black. 

I will get a photo of the 'box' (it's definitely part of the Sterling set up) and the alternator! And I will chase potential wires from the shunt.

Thank you for keeping up the help. I'm sorry some of it still goes over my head. 

Edited by Lady_Why
Link to comment
Share on other sites

3 minutes ago, Lady_Why said:

had no clue there may be an issue between the battery charger/genny  (the electrician who advised me to plug it into the mains didn't mention it) - so thanks for bringing that up! I'm in the cafe currently, but I believe this is the charger I've got: https://www.batterymegastore.co.uk/sterlingpower-ab2480.html

That is a 24 V one. 

Link to comment
Share on other sites

5 minutes ago, Lady_Why said:

had no clue there may be an issue between the battery charger/genny  (the electrician who advised me to plug it into the mains didn't mention it) - so thanks for bringing that up! I'm in the cafe currently, but I believe this is the charger I've got: https://www.batterymegastore.co.uk/sterlingpower-ab2480.html

I am guessing that the 'charge current' (A) is the amps... in which case it is 80.

Your generator will DEFINITELY not power that battery charger, at best it will stall the generator engine - at worst overload it and may do damage.

Some battery charges can be 'turned down' (I don't know if your can) If it can be turned down than take it down to 20 amp output.

 

I suggest that you fairly urgently need to get a knowledgeable person to come and review your systems - it sound like to date you have been ill-advised.

 

I'm not sure if you have said where you are, but hopefully not in London.

Where are you ?

There may be a Forum member with the knowledge you need that is within a reasonable distance and would come and help out.

Edited by Alan de Enfield
  • Greenie 1
Link to comment
Share on other sites

4 minutes ago, rusty69 said:

That is a 24 V one. 

Gah, well spotted. It was the only pic I found that looked like mine. Clearly I need to source those papers on the boat too. 
 

4 minutes ago, Alan de Enfield said:

Your generator will DEFINITELY not power that battery charger, at best it will stall the generator engine - at worst overload it and may do damage.

Some battery charges can be 'turned down' (I don't know if your can) If it can be turned down than take it down to 20 amp output.

 

I suggest that you fairly urgently need to get a knowledgeable person to come and review your systems - it sound like to date you have been ill-advised.

Can't afford having anyone come around currently and wouldn't know who to call either, tbh. There is a knowledgeable guy on FB who has offered to help if I take it to the marina but he would have to find the day for it and I feel a little bad as he's clearly very booked - however, I may have to get on to it as I have nowhere to go with it.

Can I charge with clamps? If the output is low (albeit unregulated) it's safe, no?

Edited by Lady_Why
Link to comment
Share on other sites

14 minutes ago, Lady_Why said:

I will get a photo of the 'box' (it's definitely part of the Sterling set up) and the alternator! And I will chase potential wires from the shunt.

I wonder if this magic box is an alternator controller. Def worth posting a pic. 

  • Greenie 1
Link to comment
Share on other sites

Ok, think it is this one - same high amp (90). Don't think it can be turned down but I will check the manual when I get home. This is depressing. ? 

http://tasautocraft.com.au/product/sterling-alternator-to-battery-charger-12v-90amp-ab1290/

Actually, ignore that - let me go home and find out for sure rather than guessing.

 

Edited by Lady_Why
Link to comment
Share on other sites

3 minutes ago, Lady_Why said:

Can't afford having anyone come around currently and wouldn't know who to call either, tbh. There is a knowledgeable guy on FB who has offered to help if I take it to the marina but he would have to find the day for it and I feel a little bad as he's clearly very booked - however, I may have to get on to it as I have nowhere to go with it.

Can I charge with clamps? If the output is low (albeit unregulated) it's safe, no?

If a forum member could come around it would normally be FoC (except for maybe a bacon butty and a mug of tea). Boaters help each other out and a 'damsel in distress' is near the top of the priority list.

The problem in London is access, parking and getting a big tool kit to the boat - this is why folks are reluctant to offer.

 

If you post (roughly) where you are and access availability (marina, offside mooring, tow-path mooring etc etc) then you might get an offer.

 

Yes you could charge directly from the generators 12v output but it would be a waste of time and petrol, the out put is so small you'd be better off with one of these (and it would keep you warm as well)

 

 

Pedal generator.jpg

  • Sad 1
Link to comment
Share on other sites

12 minutes ago, Lady_Why said:


I had no clue there may be an issue between the battery charger/genny  (the electrician who advised me to plug it into the mains didn't mention it) - so thanks for bringing that up! I'm in the cafe currently, but I believe this is the charger I've got: https://www.batterymegastore.co.uk/sterlingpower-ab2480.html
 

 

That is NOT a battery charger as such. It is a device for connecting to the alternator that forces the alternator to maximum output to charge the batteries. The battery charge may be the other "box" or you may not have one.

 

Such devices are often fitted to try to cover up charging system deficiencies by people who swallow the marketing hype. The problem might just be low alternator speed as Alan said and if so that device may well burn a slow revving alternator out.

 

We need photos.

 

 

 

 

  • Greenie 1
Link to comment
Share on other sites

Yeah I just realised -  I edited my last comment when realising. Will go home later and check for sure. And get all photos up for certainty! 

I am in Rickmansworth (west London), twenty meters from the Aquadrome car park. And I am happy to pay later on - I'm just skint until my next payment comes through!
 

I'm surprised the genny is useless - it was recommended to me on a boaters forum and I've seen people use it on the towpath. Goddamn... 

Edited by Lady_Why
Link to comment
Share on other sites

That so called charger is only to do with charging from the alternator, not the mains.

 

We need a PHOTO of this other box because I suspect it will turn out to be a mains battery charger and from the thin cable size not a very high output one so that generator may well power it. We need to see the labels.

 

With a Sterling A to D  and 13.4 volts I suspect the A to D or the alternator has failed. Unfortunately this device needs major rewiring to get it out of circuit properly and the wires I suspect connects it to the batteries (the two thicker ones but not as thick as the battery cables) indicates it probably is not correctly wired.

 

I will drive over later in the week if the OP wants me to, but am not sure how much good I can do. If I do so I would prefer that she has a chaperone with her.

  • Greenie 2
  • Love 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.