Battery problems, really stuck!

[Vegable]

I have 5 Rolls 135ah deep cycle lead acid batteries on my yacht which are one season old. They are kept on a Sterling 30a battery charger over the winter months and have a Rutland Wind generator working all the time through a Rutland regulator during the sailing season.
I regularly check the batteries for electrolyte levels and occasionally check the SG of each cell after disconnecting the batteries overnight from any form of supply and each other - always around 1.275 /1.300 when corrected for outside temperature. If in a marina visitting, I’ll connect to the 240v supply but that’s not often.
I have 4 batteries connected in parallel for service batteries, and one battery kept for engine starting.
I have an ammeter/voltmeter/ah meter connected to the neutral of the service batteries to monitor the current flow and voltage of the service batteries. The negatives of all 5 of the batteries are "tied together".
I'm finding that after 3 - 4 hours of sailing using my instruments and autohelm the battery volts have dropped to 12.3 volts and I have to put the engine on for approx 1 hour to recharge the batteries. Monitoring the current taken by the instruments (6 x 60+) , vhf radio, and autohelm it peaks at 6 amps and drops to 4 amps when the autohelm is in a quiet phase. (I don't have anything else running). If I put a voltmeter on all of the 4 battery terminals (nuetrals disconnected briefly) they each read 12.3 volts. I should add that the separated starting battery remains around 12.7v. The battery terminals are clean and all connections are Contralubed. And to complete the picture, although not bonded together, anodes are eroded as expected, with the exception of the prop anode which has always disappeared at crane-out. The anode at the end of the Brunston Prop is good.
If I’m on a swinging mooring and I run the Eber, (the type that’s heats water to fan blown radiator heaters) then I get 4 hrs before needing to recharge the batteries

By my understanding, batteries shouldn't be discharged below half their capacity at 12.2v as it " ruins" them which is why I start the engine at that voltage. I have never, ever let it get below that, not even once.
If I have ( for ease of calculating) 4 x 120 ah batteries they should supply me at say 6 amps draw with 40 hours of usage before I need to recharge them...using half capacity as a guide, so why do I have to recharge them after only 3hrs sailing?

Can anyone suggest what’s going on? Is my thinking wrong? Where should I start investigating.
( I don’t have a smart phone so answers will be delayed in responding to them)
Many thanks, a very puzzled
Mike

 

[johnlilley]

Perhaps a good start might be to fit a multimeter set on DC amps between the single - terminal & the - battery lead as all are linked & see what the reading is. Then start disconnecting or isolating batteries & circuits to see which one is drawing current. Just make sure you note the direction the current is going. On some batteries you might find that current is going in from a higher charged battery instead of going out, or if the wind charger or solar panels are feeding in.
Easier to fit the meter between + terminal & + lead but you are using a common - so it will give you a start in the right direction.
John Lilley

 

[BabaYaga]

I'm finding that after 3 - 4 hours of sailing using my instruments and autohelm the battery volts have dropped to 12.3 volts and I have to put the engine on for approx 1 hour to recharge the batteries.

If that is not a resting voltage, it can not be used to estimate the state of charge.

 

[macd]

That seems distinctly odd. But, as implied above, you need to let the batteries rest for a while after use to get a meaninfgul reading.

Can you offer us a drawing of exactly how the bank of four is wired? They simple way to link them isn't the right one. See here: http://www.smartgauge.co.uk/batt_con.html

Incidentally, re your observation that "batteries shouldn't be discharged below half their capacity at 12.2v as it " ruins" them", this may well not be so, depending on precisely which model you have. Rolls publish graphs for depth of cycle v lifetime cycles, which may shed a little more light on the subject. My batteries, deep-cycle Trojan 105s, suffer some loss of total lifetime Ah returned with regular deep discharging, but it's really quite modest. (With common-or-garden automotive or 'leisure' batteries, on the other hand, deep discharging is certainly a bad idea.)

It's also worth noting that recharging a battery when it's only 5 or 10% discharged is very inefficient, since they'll only accept a small amperage in that condition. If on shore power, no problem, but scarcely worth starting the donk for such a slow trickle. If they're down to 80% or less, they'll take a lot more amps.

Do you have the means to equalise the batteries? Essential with kit such as Rolls, I'd have thought?

 

[Vegable]

Perhaps a good start might be to fit a multimeter set on DC amps between the single - terminal & the - battery lead as all are linked & see what the reading is. Then start disconnecting or isolating batteries & circuits to see which one is drawing current. Just make sure you note the direction the current is going. On some batteries you might find that current is going in from a higher charged battery instead of going out, or if the wind charger or solar panels are feeding in.
Easier to fit the meter between + terminal & + lead but you are using a common - so it will give you a start in the right direction.
John Lilley

Thanks John. That's a good logical step to take and I'll try that the next time I'm on the boat. I'd totally run out of ideas.
Mike

 

[Vegable]

That seems distinctly odd. But, as implied above, you need to let the batteries rest for a while after use to get a meaninfgul reading.

Can you offer us a drawing of exactly how the bank of four is wired? They simple way to link them isn't the right one. See here: http://www.smartgauge.co.uk/batt_con.html

Incidentally, re your observation that "batteries shouldn't be discharged below half their capacity at 12.2v as it " ruins" them", this may well not be so, depending on precisely which model you have. Rolls publish graphs for depth of cycle v lifetime cycles, which may shed a little more light on the subject. My batteries, deep-cycle Trojan 105s, suffer some loss of total lifetime Ah returned with regular deep discharging, but it's really quite modest. (With common-or-garden automotive or 'leisure' batteries, on the other hand, deep discharging is certainly a bad idea.)

It's also worth noting that recharging a battery when it's only 5 or 10% discharged is very inefficient, since they'll only accept a small amperage in that condition. If on shore power, no problem, but scarcely worth starting the donk for such a slow trickle. If they're down to 80% or less, they'll take a lot more amps.

Do you have the means to equalise the batteries? Essential with kit such as Rolls, I'd have thought?

Hello Macd
The batteries are wired as suggested in the Smartguage link.
No, I haven't tried Equalizing. I'm bringing the boat back to Pwllheli next month so I'll be able to spend a lot more time trying to solve this.
I accept that the voltage reading of 12.3 volts is not accurate, but it does indicate that what started off as a potential availabilty of 240ah has diminished somewhat more than expected.
I'm also aware that just an hour of charging isn't putting sufficient charge in the batteries to get over the 80℅ soak charge level. But at times needs must.
Do you all think it'd be worth ignoring the voltage for a while just to see how low the voltage goes before I hit the panic button?
Starting a trip out of Arisaig, because it's such a tortuous passage generally means running on engine for about 45 mins before raising sails too. So everything should be tip top at the start.
Thanks for comments
Mike

At a couple of forums I've been to, the last one being the CA Bluewater forum I specifically asked about deep discharging deep discharge batteries and at both forums they said it was not to be recommended. But what's happenning to me is at every outing.

 

[duncan99210]

I don't think you've got problems with your batteries, it just that the batteries are not getting anywhere near fully charged. Even when left with no load on them, the Rutland won't be doing much more than trickle charging them. You need to look carefully at your energy input and draw. Bear in mind that it'll take the best part of 24-48 hours hooked up to the mains before your charger will have got the batteries to somewhere near the 100% mark. Then think think about how much you're putting in from the engine alternator. You're always playing catch up in terms of % charged.
I'd do an energy audit. Look at all the usage of electricity on board, estmate how long per day you use each item so that you can work out how many amp hours you use per day. Compare that usage to how much you typically get from the Rutland in a 24 hour period plus the output from your engine alternator. I suspect you'll find that there's a deficit. As to how to fill it, you might consider a beefier charger, a smart regulator for the alternator, some solar panels or a portable generator if you keep the boat permanently on a mooring.

 

[macd]

1. Do you all think it'd be worth ignoring the voltage for a while just to see how low the voltage goes before I hit the panic button?

2. At a couple of forums I've been to, the last one being the CA Bluewater forum I specifically asked about deep discharging deep discharge batteries and at both forums they said it was not to be recommended. But what's happenning to me is at every outing.

1. Better would be to rest them, if you can. Even 30 minutes doing nothing will give you a more accurate reading. I think you're right to be cautious, which means finding any unidentified drain on your batteries first (if there is one). A few hours running with the drain you believe you have isn't going to hurt anything, but the ideal place to find out that for sure out is in harbour, not at sea. But batteries under discharge will always return a volts figure lower than the true one, so the true situation can be expected to be better than your voltmeter tells you. Have you tried SG-testing them when the meter claims 12.3V? That should give you a figure you can believe. (Incidentally, even if 'real' 12.3V isn't exactly deeply discharged...about minus 35%...but far more than you'd expect from the use you describe if they started out full.)

2. Well, you can take their word for it. Or Rolls'. Up to you. "Don't deep discharge" is an easy mantra, bit like the way many GPs tell you it's bad to drink when on antibiotics (which usually isn't the case but they can't be bothered to look it up). I'm satisfied that deep discharging of my Trojans will not substantially diminish their total lifetime Ah. But, as said, look at Rolls own graph, do the sums and make up your own mind. (That said, I like to discharge mine as little as practicable (usually easy with 4 x 85w solar panels)...)

Ah, Arisaig. Lovely spot. Fair winds.

 

[skyflyer]

I am led to believe that an occasional deep discharge will not do too much harm so long as the battery is not left in that state and is recharged to a much higher state quickly. This prevents the lead sulphate hardening on the plates which is when reversing the reaction becomes all but impossible.

Many so called deep-cycle batteries are nothing of the sort. At best they are a dual purpose compromise. True deep cycle batteries are bloody expensive (although not all bloody expensive batteries are deep-cycle, of course) but are designed for frequent deep discharging. I suspect the Rolls may well be one of those!

 

[RichardS]

As others have said, you need to make sure that batteries are 100% charged before drawing too many conclusions about how long they are lasting. I know you're using SG but how about a good charge on a mains charger and, whilst still on charge, check that the voltage across each battery is at least 14.4V. If the Rutland can't achieve this it is not charging the batteries fully.

After resting for several hours (12 hours if possible) with the charger disconnected and no load the voltage should have dropped from 14.4V to around 12.7V. You then know that you are starting at 100%.

If you need continous power you might be able to disconnect the batteries when they are fully charged and run the boat from the charger for 12 hours.

Richard

 

[Vegable]

Thanks for your comments and are much appreciated.
As macd has suggested I found this on the Rolls Barden site http://www.rolls-battery.com/conten...cf0f71e01d23&phpMyAdmin=9dec4a269d70t7a63be7c which in table 2 seems to suggest that under load 11.58v is about the 50% discharge state in which case I have been worrying unecessarily and restricting equipment use ( echomax, radar, navtex, gas sniffer, fridge, all not used unless under engine power because of current drain) however I do need to take the sg under load in order to verify this.
A little knowledge can sometimes lead you into all sorts of problems.
Thanks again
Mike

 

[pvb]

.... however I do need to take the sg under load in order to verify this.

I don't think you'll find that the SG varies much under load.

 

[Ian_Edwards]

You might consider adding a battery monitor.
I use a Merlin Smartgauge:

http://www.merlinequipment.com/markets/group.asp?groupid=48

It's very simple to install and you can see the status of the domestic battery bank just by pressing a button. It saves a lot of messing about with multimeters, disconnecting wires and waiting for batteries to rest.

and as said above, I'd seriously look at upgrading your method of charging, by either uprating the alternator or adding a alternator to battery smart charger, or both.

 

[SOT]

You say in the op that you have a shunt fitted and and therefore I assume you have an ah meter. You mention voltages but don't say anything about the ahs used or the state of charge shown. That information would help in diagnosing the problem.

 

[ghostlymoron]

The consumption of your autopilot sounds high to me, 4a minimum. Have you got excessive friction in the system or does it need lubricating?

 

[macd]

I don't think you'll find that the SG varies much under load.

+1
It's not a 'volatile' value. It changes slowly and progressively with the state of charge: not with the transient voltage.

...I found this on the Rolls Barden site http://www.rolls-battery.com/conten...cf0f71e01d23&phpMyAdmin=9dec4a269d70t7a63be7c which in table 2 seems to suggest that under load 11.58v is about the 50% discharge state...

I suspect that 11.58 figure is under a somewhat higher load than you describe in your opening post. Nonetheless, you can see that load voltages are highly volatile, and it's in that context that you should view your 'worrying' 12.3V reading. For more reassurance, I'd urge you again to take SG readings on the fly if you can. They're real. Really, really real

 

[Poecheng]

V,

You have a great set up that is correctly wired :encouragement: for a large bank - few of us could get that capacity or such quality batteries.

May I make a few suggestions which are intended to help overall and which repeat some of the above with my intentionally rather prescriptive suggestions.

Monitoring
You need confidence and ease of readings because you are spending time worrying about what is happening and also not putting the fridge on !. Fit a Smartguage or a NASA BM2 and then you know your state of charge. People have their favourites; both work.

Capacity
Great with what you have but even better if you could make it a bank of 5 x Rolls and add a Red Flash for the engine. The RF will go almost anywhere and it frees the deep cycles to do what they do best - run things whilst the engine is off.

Engine charging
Suspect that the battery capacity has seriously outgrown the alternator - especially so as you like to sail and not use the alternator much. If you have the boat in your profile (W O-R) then the alternator will probably not be putting out "modern" voltages at the battery terminals. More modern internal alternator regulators put out about 14.4v.
You could swap for a larger alternator with a modern internal regulator putting out a higher voltage. Or you could fit an Adverc to your existing set up which will ensure that the correct charging voltage is applied at the battery terminals and get the best out of what you have.
Having spent what you have on batteries I would do both - get a modern uprated alternator and fit an Adverc and ensure the alternator cables are good. There is plainly a limit to how much charge can be put in with just 45m on the engine but this would maximise it.
It is a reasonable argument that you don't need an Adverc with a modern alternator - I just don't agree and would fit both. If you were feeling flush you could put a Balmar alternator and controller in there. However, you will get 99% of the Balmar's benefits from a decent Prestolite and Adverc set up. Likely that the alternator belt will need to be a multigroove thingy.

Non-engine charging
I always found my windgen to put in less than hoped. Most of us don't like sailing or being on board in gales when they work ok.
You surely have space on a W O-R for an easy 100w of semi flexibles. (2 x 50w @£90 each) Connect them up to a Victron MPPT regulator (£80 plus some cables) and you will find they will fully charge your batteries when you are not around and (almost) keep up with your present consumption on a sunny day. Major difference. if you can, get a couple of extra panels that you put out at anchor and link up to the others - then you can have your fridge on and charge your batteries and have fun watching the amps go in the batteries

All IMHO and deliberately just one person's view

 

[Mike k]

one of your batteries could be knackered and that impacts the rest. That happened to me!. Are you sure all are healthy?

 

[Vegable]

Thanks Poecheng and others who suggest that the batteries aren't charged to begin with. I have a Volvo D1 30 with a 115a alternator, feeding the batteries through a mosfet and adverc. The winds in Arisaig provide enough puff that when I board the boat the shunt light on the rutland regulator is lit and the battery volts are at 14.2. I check..... everytime! Both with the battery monitor (a Battman II) and with a digital multimeter. Living in N.Wales and sailing from the NW of Scotland means that the boat is left for long periods between visits. I also have a small 30w solar cell mounted on the deck too. i don't have concerns about the alternator not being able to stuff in enough power. I've checked the cable, the connections and the brushes! It's the loss of power that concerns me. I was craned in not long ago after having the batteries on charge all winter. After 4 hours of running the eber the volts had dropped to my 12.3 self imposed limit. It was the snowy week at the end of April. So it's not the charging that's at fault. However thanks for your thoughts. They are appreciated, and noted, and once I can identify the source of my problem some of your ideas will be acted upon.
Ghostlymoron, the 4 to 6 amps is the draw with 5 Raymarine 60+ instruments, Raymarine Chartplotter, vhf radio, AND the autohelm on.
Pete (prv) and macd have now thrown me saying that the sg won't vary and you've lost me now. The Rolls site seems to say take sg readings yet you both say that sg won't vary. Macd also says take sg readings when the volts read the magic 12.3v (after leaving for 30 mins or so).
I'm sorry, I'm stuck again
Mike

 

[Poecheng]

V,
Well you have a crackin' set up then ! Even more frustrating that you have this problem, I'm sure.
Is there anything which is wired directly to the battery or prior to the battery monitor position and which will take its current out without those amps showing on the Battman II - windlass, bowthruster, emergency bilge, Eberspacher? I am not suggesting the bowthruster is thrusting and you are not noticing you are going round in circles but something causing losses once the batteries are turned on or its drain is no longer matched by the (admittedly low level) charging of the windgen/solar