Another battery/engine question

[andyo]

Hi – I would appreciate comments on my thoughts on battery and electric arrangements on our newly bought Konsort.

The Konsort is old (1980) but seems well-maintained. It has the original Bukh 20hp engine, a wind generator and solar panel. Last time we went over to Essex for a sail we couldn’t go out as the engine wouldn’t start. It turned over a few times, but eventually I think the batteries had dropped so much that it wouldn’t turn over fast enough to start. I had a close look at the batteries. We have 3 110 Ah leisure batteries, and the common rotary 1, 2, 3 off switch. There is also a battery charger, but I think this is a bog-standard one as you may have for a car.
I’ve read around a fair bit in these pages in the last couple of weeks and think that I should buy a starter battery and use that only to turn the engine. We could also probably do with a modern battery charger. We have shore power in the marina, but I’ve been loath to leave this connected when we are not there – especially with, as I say, an old-fashioned battery charger. I also need to see if the wind generator and solar panel do actually provide any charge to the batteries.

So some questions, starter battery for the engine? New, modern charger? Can/should I leave the shore power connected when not on the yacht, can the charger be left connected to the batteries all the time (previous owner advised removing the croc clip when the charger was not actually switched on.)

I apologise for the length of this post, but I really would appreciate some guidance in this area.
Thanks,

 

[VicS]

Hi – I would appreciate comments on my thoughts on battery and electric arrangements on our newly bought Konsort.

The Konsort is old (1980) but seems well-maintained. It has the original Bukh 20hp engine, a wind generator and solar panel. Last time we went over to Essex for a sail we couldn’t go out as the engine wouldn’t start. It turned over a few times, but eventually I think the batteries had dropped so much that it wouldn’t turn over fast enough to start. I had a close look at the batteries. We have 3 110 Ah leisure batteries, and the common rotary 1, 2, 3 off switch. There is also a battery charger, but I think this is a bog-standard one as you may have for a car.
I’ve read around a fair bit in these pages in the last couple of weeks and think that I should buy a starter battery and use that only to turn the engine. We could also probably do with a modern battery charger. We have shore power in the marina, but I’ve been loath to leave this connected when we are not there – especially with, as I say, an old-fashioned battery charger. I also need to see if the wind generator and solar panel do actually provide any charge to the batteries.

So some questions, starter battery for the engine? New, modern charger? Can/should I leave the shore power connected when not on the yacht, can the charger be left connected to the batteries all the time (previous owner advised removing the croc clip when the charger was not actually switched on.)

I apologise for the length of this post, but I really would appreciate some guidance in this area.
Thanks,

A 1,2,3, off switch.... Not come across one but that does not meean they dont exist

Usually 1,2, both, off and would expect two of the batteries to be linked to form a 220Ah bank for domestics and the other for engine starting. Probably a 60 or 70 Ah would have a high enough CCA for engine starting. So yes would suggest a medium sized car starter battery for that purpose.

If the combined might of all three batteries could not crank the engine you are probably looking at replacing all in the not to far distant future unless they respond to charging

Need to look at the charger to determine what it is . Croc clips so not multiple outputs. Automatic multi-stage or non automatic ? Would really want automatic if to be left on. But with wind and solar you should hardly need a battery charger. Just a decent sized plug in and clip on one for emergencies perhaps.

Need to check how wind charger and solar panel are connected and what regulation there is and if they both work.

Need to check out shorepower system .... safety aspects etc ... Galvanic isolator needed if plugged in all the time and earth bonded to boat systems ????

Dont aplogise for length of post ....... need more detail really. Makes, models etc ......... and post a wiring diagram!

 

[ghostlymoron]

The first thing i would do is do a survey and see what's connected to what. (don't bother about the little stuff from the distribution board initially ). Then put a meter on the solar and wind to see what they're producing. Have a look at charger and see what it says on the information label. If you leave the charger switched on overnight the battery should have enough oomph to start the engine. Check all connections on charging circuits and report back.

 

[lpdsn]

I’ve read around a fair bit in these pages in the last couple of weeks and think that I should buy a starter battery and use that only to turn the engine.

A dedicated starter battery is the best arrangement IMHO. It doesn't have to be big. A reasonable value one from an auto factors is good enough.

Put the other batteries into a single domestic bank.

Lose the 1-2(-3) switch - they're the spawn of the devil, again IMHO, - better still, sell it to another forumite who swears by them rather than at them.

Have a separate switch for each bank and a means of starting the engine from the domestic bank. By that I mean a connecting the domestic battery to the starter circuit, not linking the domestics to a dead starter battery as some people do.

With a good charger that will switch to trickle charge when the battery is charged, you can leave the shorepower connected all the time. It's a risk to leave something like a fridge on, as it could drain the batteries if someone disconnects your shorepower.

I charge my engine battery using one output from a Sterling charger and the domestics using the other two outputs combined. I have considered adding a dedicated engine battery charger, as I saw a Chinese smart charger for about £15, but I suspect that project will not get off the ground - too many others ahead of it in the queue.

 

[Poecheng]

I agree with Ghostly about the audit.
You want a multimeter to check voltages to see what is happening.
Check the voltages of the individual batteries - this might not tell you much at this stage as they may all have become equal by the way things have been used.
With the battery switch in "off" (which is how the boat will be left when not used) but with the wind generator (hopefully) generating you should have a voltage well above 12.6v (and more like 13.5 to 14.5 volts). If not then either the WG is not working or it has been wired into the wrong side of the main battery switch.
Same with the solar.
If they have been wired correctly and are providing a charging voltage (ie above 13.5v ) then your batteries should have been charged sufficient to start the engine [I know 13.5v is not enough for proper charging but would do enough for this purpose over time]

To start your Bukh in this weather: have you got a cold starting aid on the Bukh (an electrical thingy that heats the air intake)? When starting from cold (especially with poor battery) I would use the decompressor to get the engine spinning before dropping that to compression. If things were really cold and rubbish battery I would use the handstarter to get the engine moving initially - to break the friction/inertia.

Suggest you treat yourself to a CTEK charger (it need not be massive as you will have lots of time to charge) and get the batteries charged up one by one and then see what condition they are in.

 

[charles_reed]

One of the problems with a direct wired PV panel is that it really doesn't charge the battery it just reduces the drain on it. As already pointed out most batteries need an input of 13.8-14.5v to charge.
One of the problems with rotary switches is that they frequently corrode and stop making good contact.
Before doing anything else its probably a good idea to check and re-make all your battery terminals.

The idea of a simple switch mode charger, to diagnose battery condition is a good one - and CTek IMHO are good value for money. Just take each battery out of use, charge it to float, then stop the charge and leave it an hour. Then record the voltage, it should be at least 12.5v and may be 12.9. Leave it for 24 hours and take the voltage again - if it's dropped more than 3-4% that battery is suspect. Once you've checked all your batteries you can move on to other parts of the system.
You need to be aware that you may be getting full voltage at the end of a wire, but it won't take sufficient current to operate the electric unit - the misleading fallacy of a voltmeter.

 

[Jim@sea]

The 2 x 12v 110amp batteries in the boat I have bought were new in 2011 and I may replace them in the spring ready for the new season, however I don't think they are big enough, your engine is a 20 hp whereas mine is a 60 hp, Certainly all these 12v 110amp batteries seem to be fitted to everything, perhaps because they are light and a chandler can stock them and lift one into a customers car. however Tractor dealers don't seem to stock these 110amp batteries and have a range more suitable for bigger engines.
So as there is room in my bilges I will buy a 12v 150 amp battery (as a spare) and have "Jump Leads" handy. OK I might have to get help lifting it in, but this is the very reason that chandlers don't stock bigger batteries.
(and in 1982 I bought a Nauticat which had the original 1974 batteries and they were enormous but old and I mad the mistake of buying 2 new 110 amp Exide batteries and one failed and when I took them back under warranty I was told that they had been the subject to a recall and should not have been sold. Perhaps the 12v 110amp batteries are the biggest they can make to be cheap without going for heavy duty construction. After all for £70 you are not actually paying a lot of money)

 

[ghostlymoron]

It's not high Ahr that you need to start an engine, its CCC (cold cranking capacity) plus a bit in reserve. I would think also that if you want to provide more capacity it would make more sense to get 2 x 75Ahr ones in parallel instead of risking a hernia with a 150 Ahr that you can hardly lift.

 

[richardabeattie]

The OP says the engine won't start and suspects it's the batteries. It's not a particularly big engine so surely the first thing to do is to connect an ordinary starter battery directly to it and check that the engine itself is OK. Only then start delving into the cleverer stuff?

 

[William_H]

One of the problems with a direct wired PV panel is that it really doesn't charge the battery it just reduces the drain on it. As already pointed out most batteries need an input of 13.8-14.5v to charge.

Charles this sounds misleading to me. A direct connected PV panel will typically produce 18 to 20 volts no load. This means that connected to a 12v battery it will pump current in depending on the wattage of the panel and sunshine. So in full sun a 20w panel will push 1 amp into a battery. Regardless of voltage (charge state) of battery. So concern for a direct connected PV is overcharge of battery (boiling) However not really a concern for small PV panel and large batteries. Of course large (many parallel) batteries have more natural loss of charge anyway.

Regarding battery chargers I am not a fan of auto chargers. An old style charger (hopefully) with an amp meter can do an excellent job provided you do not leave it connected too long. Overnight may be OK but not longer. The problem with any charger connected to the mains long term is the problem of current from the earth system causing galvanic corrosion of under water parts. hence you may need a galvanic isolator to minimise this long term small current to the water. It gets complicated. So i reckon keep the old charger. Just be aware of the current it is charging at and relate this to your battery size. (connect all together for charging)
1,2,both ,off switches are OK provided you know what you are doing with battery management and are dillegent.
Lastly large batteries connected in parallel work Ok until one battery has a problem. Then the worst condition battery dictates the whole performance. So If in doubt about battery condition separate them and check individually. recharge each individually then check individually for engine crack performance and how long it can run lights etc.
Your engine start problem is most likely a wiring fault (bad connection which may get hot) or bad battery(ies). A volt meter on the battery terminals when cranking the engine will quickly show if batteries are bad. Volts will fall bellow 6v when cranking. If voltage remains near 12v you have a wiring problem . About 9 or 10v for a typical small start battery is normal when cranking. More for a larger battery.
Whilst large deep cycle batteries don't usually have a cold cranking amp rating like a small start battery will. Being big batteries they will inevitably have a good cranking capbility. Not big compared to their size but still big) Starter batteries like for a car have a large cranking current capability for their size but relatively small capacity for long term long current supply.
good luck olewill

 

[charles_reed]

It's not high Ahr that you need to start an engine, its CCC (cold cranking capacity) plus a bit in reserve. I would think also that if you want to provide more capacity it would make more sense to get 2 x 75Ahr ones in parallel instead of risking a hernia with a 150 Ahr that you can hardly lift.

one actually needs a reserve of capacity to cover things like bleeding the engine (from memory the Bukh doesn't self-bleed0. However the main criterion should be CCA.

 

[charles_reed]

On PV panels

<<Charles this sounds misleading to me. A direct connected PV panel will typically produce 18 to 20 volts no load. This means that connected to a 12v battery it will pump current in depending on the wattage of the panel and sunshine. So in full sun a 20w panel will push 1 amp into a battery. Regardless of voltage (charge state) of battery. So concern for a direct connected PV is overcharge of battery (boiling) However not really a concern for small PV panel and large batteries. Of course large (many parallel) batteries have more natural loss of charge anyway.
Charles this sounds misleading to me. A direct connected PV panel will typically produce 18 to 20 volts no load. This means that connected to a 12v battery it will pump current in depending on the wattage of the panel and sunshine. So in full sun a 20w panel will push 1 amp into a battery. Regardless of voltage (charge state) of battery. So concern for a direct connected PV is overcharge of battery (boiling) However not really a concern for small PV panel and large batteries. Of course large (many parallel) batteries have more natural loss of charge anyway.>>

WilliamH
You may consider this misleading but in my experience of 14 years of using PV panels on my boat I've found this to be usually the case. The exception only occurs with a top-end MPPT charger being fed volts well above system volts. Even then my 24v input to a BZ charger only results in a charge voltage about 1 above system volts, and that is with 328 nominal watts of PV panels.
I think you're misleading yourself by quoting the open-circuit volts of a PV panel - only achieved by having an MPPT controller. Under load it will put out a similar voltage to the battery bank.
I would agree that the reported symptoms are most likely down to poor connections, probably either battery or solenoid.

 

[Storyline]

Think that with a wind generator you should not need to keep a battery charger permanently connected. Every time we come to our boat the batteries (3 x 110ah + engine start) are always fully charged by our Rutland 913. You also have solar so should be even better. As others have said do not leave a cheap charger permanently connected - you need a 3 stage charger with a trickle function for that. Sounds to me like your batteries are knackered or the wind/solar are not connectd properly.

Just in case you missed Vic's point above, do not forget to fit a galvanic isolator if leaving your boat connected to shore power.

 

[William_H]

<<Charles this sounds misleading to me. A direct connected PV panel will typically produce 18 to 20 volts no load. This means that connected to a 12v battery it will pump current in depending on the wattage of the panel and sunshine. So in full sun a 20w panel will push 1 amp into a battery. Regardless of voltage (charge state) of battery. So concern for a direct connected PV is overcharge of battery (boiling) However not really a concern for small PV panel and large batteries. Of course large (many parallel) batteries have more natural loss of charge anyway.
Charles this sounds misleading to me. A direct connected PV panel will typically produce 18 to 20 volts no load. This means that connected to a 12v battery it will pump current in depending on the wattage of the panel and sunshine. So in full sun a 20w panel will push 1 amp into a battery. Regardless of voltage (charge state) of battery. So concern for a direct connected PV is overcharge of battery (boiling) However not really a concern for small PV panel and large batteries. Of course large (many parallel) batteries have more natural loss of charge anyway.>>

WilliamH
You may consider this misleading but in my experience of 14 years of using PV panels on my boat I've found this to be usually the case. The exception only occurs with a top-end MPPT charger being fed volts well above system volts. Even then my 24v input to a BZ charger only results in a charge voltage about 1 above system volts, and that is with 328 nominal watts of PV panels.
I think you're misleading yourself by quoting the open-circuit volts of a PV panel - only achieved by having an MPPT controller. Under load it will put out a similar voltage to the battery bank.
I would agree that the reported symptoms are most likely down to poor connections, probably either battery or solenoid.

Hi Charles forgive me for seeming to argue.
The open circuit voltage of a PV panel is indeed just that. The actual voltage falls with current from the panel.(a resistive load) (conversely less current means more volts) When charging a battery directly from the panel of course it is difficult to measure the voltage of the panel because you are measuring the voltage of the battery. However an amp meter will show that current is pushed into the battery reducing only slightly from a battery voltage of 11.5 to 14v. Even if you artificially added say another 4v battery in series so battery volts were 16 the panel would in good sunshine still shove current in. Indeed the number of cells (equals voltage) is chosen to give a voltage enough to charge a battery in less sunshine. Hence with small panels it can be quite reasonable to not have a controller at all. But an MPPT will give more current.
Of course in practice a small panel in limited sunshine not aligned to the sun will give only a small current which may only keep a battery from going flat.But a bigger panel around here will charge and even cook a battery. (35 degrees max today and only mid spring)
olewill
By contrast an MPPT controller will provide a less voltage but one chosen or varied to give appropriate charging to the battery. So no concern about overcharge.