I'm still confused electrical knowledge required

[WotEver]

And Mike thanks for pointing out the theoretical capacities of my batteries. But I really would like to stay with what I assumed I'd bought, and that is 4 New 110ah batteries.

What you originally installed and what you have now are almost certainly two entirely different things.

 

Mike estimated your current capacity at 150Ah. I was a little more optimistic at 200Ah. It's irrelevant what you started off with, it's their current capacity with Sulphation that's more relevant right now.

 

Snib suggested that there could be a stray current draw (we came across one where the alternator was drawing over 2A continuous recently). With the TV and lights off have you checked the current draw?

 

Come to that, with the TV and lights ON have you confirmed the current draw?

 

You asked a question and have been given the two possible answers...

1) You haven't been charging the batteries high enough often enough and they are heavily sulphated. A Specific Gravity reading could ascertain this if you have open wet batteries. You omitted to answer the question asked more than once as to what the batteries are.

 

2) There is an otherwise unknown draw on your batteries. You have omitted to answer whether you have checked for this.

 

The answer is one (or both) of the above but we're not magicians - without answers from yourself about the above we can't go any further.

 

Tony

[MtB]

And Mike thanks for pointing out the theoretical capacities of my batteries.

 

 

Excuse me but no, I have pointed out the actual capacity of your batteries, calculated from the figures you gave.

 

The theoretical capacity is what you thought you were buying, and what's written on the label...!

[Loafer]

Green. Made me giggle.

[cuthound]

My my my. Here we go again. I have given you the total figures of output from anything that draws current. Except my water pump. But as at best I only used it to fill a kettle didn't think it worth a mention. As for fridges. Oh please. My third one is unused on the bow. As my problem has been ongoing since last spring. Therefore I do not have a fridge in the system yet. And Mike thanks for pointing out the theoretical capacities of my batteries. But I really would like to stay with what I assumed I'd bought, and that is 4 New 110ah batteries.

One of my problems on the Stort and Lee, is that I have yet to hear of or meet a marine engineer/electrician that gives me confidence that he knows more than I do.

They seem to always be stabbing in the dark, leading me to believe that all the BS will just be increasing my bill at the end. I'm on holiday for a couple of weeks in March and on my return will be heading through London towards Oxford. Maybe on my travels I will be put in touch with a decent honest engineer. Maybe. !

Clive Mant is a good engineer/electrician based around Cropedy. Not cheap through. 07904031758.

[valrene9600]

My my my. Here we go again. I have given you the total figures of output from anything that draws current. Except my water pump. But as at best I only used it to fill a kettle didn't think it worth a mention. As for fridges. Oh please. My third one is unused on the bow. As my problem has been ongoing since last spring. Therefore I do not have a fridge in the system yet. And Mike thanks for pointing out the theoretical capacities of my batteries. But I really would like to stay with what I assumed I'd bought, and that is 4 New 110ah batteries.

One of my problems on the Stort and Lee, is that I have yet to hear of or meet a marine engineer/electrician that gives me confidence that he knows more than I do.

They seem to always be stabbing in the dark, leading me to believe that all the BS will just be increasing my bill at the end. I'm on holiday for a couple of weeks in March and on my return will be heading through London towards Oxford. Maybe on my travels I will be put in touch with a decent honest engineer. Maybe. !

I hope you find that honest engineer but bear in mind if you don't answer his questions he will be stabbing in the dark and you will think him also full of bs.

It's highly possible you could get the answer here for free before your holiday. Give it a try.

Edited February 20, 2016 by valrene9600

[Tony Brooks]

My my my. Here we go again. I have given you the total figures of output from anything that draws current. Except my water pump. But as at best I only used it to fill a kettle didn't think it worth a mention. As for fridges. Oh please. My third one is unused on the bow. As my problem has been ongoing since last spring. Therefore I do not have a fridge in the system yet. And Mike thanks for pointing out the theoretical capacities of my batteries. But I really would like to stay with what I assumed I'd bought, and that is 4 New 110ah batteries.

One of my problems on the Stort and Lee, is that I have yet to hear of or meet a marine engineer/electrician that gives me confidence that he knows more than I do.

They seem to always be stabbing in the dark, leading me to believe that all the BS will just be increasing my bill at the end. I'm on holiday for a couple of weeks in March and on my return will be heading through London towards Oxford. Maybe on my travels I will be put in touch with a decent honest engineer. Maybe. !

 

If your return to Oxford is via the Thames and if you can find a mooring close to free car parking around Reading (I would suggest a side trip to Burghfield Bridge) I will happily come and have a look completely FOC so I will not be giving you a load of bull. However I agree it sounds like lack of battery capacity from whatever cause. I will be able to check the charging voltage. I will be able to check for a permanent drain. With the battery loads you state I will have difficulty checking the alternator's maximum output unless I get to you before the first start of the day. I will not be able to check battery capacity. If they are wet open cells I will lend you a hydrometer so you can check the battery's relative density unless the batteries are readily accessible the I will do it. I can also measure the normal load on the batteries when you turn your usual appliances on.

 

I will give you my honest opinion but then it is up to you to do any work.

 

PM me if you want to take this up and then PM me again a few days before you arrive.

 

Edited to add:

 

Maybe when the Smartguage says 100% disconnect each battery in turn for a while so you are running with a 330 Ah bank. Leave the disconnected one for a week and then measure the voltage of the disconnected battery. It should read 12.5 V or more. If its lower then it probably has a n internal short circuit. Notice that this needs time to do so you would be the one to do it.

 

Exceptionally rarely you get a battery with an intercell link not properly formed and that can give all sorts of odd and random symptoms but on your usage figures I very much doubt this is the fault.

Edited February 21, 2016 by Tony Brooks

[Rob-M]

 

If your return to Oxford is via the Thames and if you can find a mooring close to free car parking around Reading (I would suggest a side trip to Burghfield Bridge) I will happily come and have a look completely FOC so I will not be giving you a load of bull. However I agree it sounds like lack of battery capacity from whatever cause. I will be able to check the charging voltage. I will be able to check for a permanent drain. With the battery loads you state I will have difficulty checking the alternator's maximum output unless I get to you before the first start of the day. I will not be able to check battery capacity. If they are wet open cells I will lend you a hydrometer so you can check the battery's relative density unless the batteries are readily accessible the I will do it. I can also measure the normal load on the batteries when you turn your usual appliances on.

 

I will give you my honest opinion but then it is up to you to do any work.

 

PM me if you want to take this up and then PM me again a few days before you arrive.

A very generous offer, greenie awarded.

[bottle]

Just to throw in another factor, the battery bank has a label(s) stating a figure (440 amp.hr).

 

Even if new, fully charged at this time of year they it will not be a 440 amp.hr bank. it will only be that if new, fully charged and the battery bank is at 25°C.

Even new ones will possibly not be that, as per Trojan threads

 

Check specification of batteries.

 

Having said that, I can only agree with other posts, if there is not a current leakage, lack of charging is very likely the problem.

 

Batteries can be knackered in days, let alone weeks if not charged correctly.

[Terryb]

Once again chaps I bow to your knowledge.

Also apologies for not answering your queries. (I didn't see them) Dan posted earlier on the general forum regarding the problems that thick posters (like me) are finding the techno babble confusing. The thing is,when someone has a query it stands to reason that they do not have the answers to said query. So to berate the op because they didn't answer everything is making things worse. Thank you very much Tony. Your offer if not taken up has without doubt made sure that I will come and visit in person when I get closer.

As for the Un answered questions. I have sealed batteries so can not check SG. Regards to current drain, until I get the clamp meter that's on hold. Though I will say that when I switch off at night my SoC remains unchanged in the morning. As has been suggested I will, one at a time remove and service the batteries in the hope that the rogue one/s can be found.

 

PAUL. Could you explain " tail current"

And how with an Amp meter I could check it please.

 

TONY. Would leaving the battery off

Show up sulphation as well.

 

EVERYONE ELSE. I wish I hadn't sunk the boat as everything was OK to start with.

But as the engineer that " fixed " the alternator actually didn't. And another subsequent engineer ripped me off for my 6 batteries. Please try to empathise that I have these problems despite throwing money at the professionals I trusted to fix them. If my crankshaft needs changing I can do that. But if a tiny diode packs in. . . I am lost. Electrickery eh. My nemesis. Thank you. Really even Mike. Thank you.

[ditchcrawler]

Am I getting really confused or is TeryMegamAlfi the same chap that a memeber went to see to sort out his charging, or is this the boat that sunk? Sorry for being so confused.

[Paul C]

Tail current:

 

When a battery is being charged, initially it allows/accepts a load of current, since its flattish and wants to be charged. Gradually as it becomes more and more charged, it is unable (physically) to accept current at such a high rate, and the battery itself limits the amount of current it can take in. As it approaches 100% state of charge, this current never reaches zero but it will (gradually) fall and fall to a very low amount. This is the tail current.

 

Typically, a good tail current to aim for is 1% of its capacity in Ah, for example a 440Ah bank which only accepts 4.4A, is approaching fully charged.

 

Be aware that Victron battey monitors (in fact I think , all Amp hour counters) use this to determine full charge and "flip" to 100% but Victron's default settings are set at a daft 4% of battery capacity. Others have reported tail currents as low as 0.5%. Also worth bearing in mind, if your battery bank is sulphated and its capacity is reduced, its the % of this reduced capacity, not the original.

 

 

BASICALLY: Tail current is a good way to determine a battery is (as good as) fully charged and is quite easy to measure.

[RLWP]

5erry,

 

I notice this is your third forum profile.

 

 

Am I getting really confused or is TeryMegamAlfi the same chap that a memeber went to see to sort out his charging, or is this the boat that sunk? Sorry for being so confused.

 

Probably

 

Richard

[valrene9600]

Boat that sank sadly.

[valrene9600]

Very clear explanation of tail current....thankyou.

I assume I can measure it with my newly acquired clamp meter using the cable from alternator to batteries.

[Paul C]

Very clear explanation of tail current....thankyou.

I assume I can measure it with my newly acquired clamp meter using the cable from alternator to batteries.

 

Tail current is what goes into the batteries. So it MUST be measured on the wire, the ONLY wire, that goes to a battery terminal. If you have other connections to that terminal and you measure "upstream" of this, then it won't be tail current, it will be tail current + something else.

 

Can you draw a simple diagram of your wiring (near the batteries) and show where you think you should be measuring it?

[valrene9600]

Tail current is what goes into the batteries. So it MUST be measured on the wire, the ONLY wire, that goes to a battery terminal. If you have other connections to that terminal and you measure "upstream" of this, then it won't be tail current, it will be tail current + something else.

 

Can you draw a simple diagram of your wiring (near the batteries) and show where you think you should be measuring it?

Sorry not at moment as I have severe back strain and have no memory of the wiring going to batteries.

So providing the alternator wire is the solitary wire to the terminal it will be accurate.

[Paul C]

It needs a diagram to easily explain.......I'll try to come up with one.

[Tony Brooks]

Once again chaps I bow to your knowledge.

Also apologies for not answering your queries. (I didn't see them) Dan posted earlier on the general forum regarding the problems that thick posters (like me) are finding the techno babble confusing. The thing is,when someone has a query it stands to reason that they do not have the answers to said query. So to berate the op because they didn't answer everything is making things worse. Thank you very much Tony. Your offer if not taken up has without doubt made sure that I will come and visit in person when I get closer.

As for the Un answered questions. I have sealed batteries so can not check SG. Regards to current drain, until I get the clamp meter that's on hold. Though I will say that when I switch off at night my SoC remains unchanged in the morning. As has been suggested I will, one at a time remove and service the batteries in the hope that the rogue one/s can be found.

 

PAUL. Could you explain " tail current"

And how with an Amp meter I could check it please.

 

TONY. Would leaving the battery off

Show up sulphation as well.

 

EVERYONE ELSE. I wish I hadn't sunk the boat as everything was OK to start with.

But as the engineer that " fixed " the alternator actually didn't. And another subsequent engineer ripped me off for my 6 batteries. Please try to empathise that I have these problems despite throwing money at the professionals I trusted to fix them. If my crankshaft needs changing I can do that. But if a tiny diode packs in. . . I am lost. Electrickery eh. My nemesis. Thank you. Really even Mike. Thank you.

 

Tail current = the small current flowing towards the end of charging. Assuming a clamp type ammeter you just set the meter to amps and put the clamp it around the main battery lead (pos or neg) and take a reading. Exactly what the tail current should be - like so much to do with batteries - is variable but the consensus suggest between 1% and 2% your battery capacity but in amps. So 440 Ah of battery charge until between 4 and 8 amps flowing.

 

The only way to test for sulphation is to fully charge the batteries and then put a know load on them and note the time taken for the voltage to drop to (I think) 11.8 volts. Ideally with a 440 Ah bank you would use a load of about 22 amps so it takes about 20 hours to drop. However even then it will not be particularly accurate for a number of reasons. Remember that Mike has already given you a guestimate of your capacity base don your discharge figures.

 

If you had wet open cell batteries you could compare the rested battery voltage with the relative density reading for state of charge. If they differ a fair bit your batteries are sulphated. If the end of your batteries are bowing out they are sulphated.

 

If your state of charge really does stay the same over night it is less likely that you have a shorted cell or a permanent drain because either will pull the voltage down a bit - or a lot. However I would prefer you to use the voltage readings rather than the SG percentage.

 

I am afraid that you need to understand that we get the same lack of info and non-responses to questions over and over again and it becomes very difficult to stay civil when it looks as if the questioner is ignoring advice and questions but keeps asking more questions that can not be answered. If you do not understand something ask about or or if you can not do something explain why.

[ditchcrawler]

Sorry not at moment as I have severe back strain and have no memory of the wiring going to batteries.

So providing the alternator wire is the solitary wire to the terminal it will be accurate.

No it wont be, even if it goes straight from the alternator to the battery terminal there will be other cables running from that terminal feeding other circuits

[Tony Brooks]

Sorry not at moment as I have severe back strain and have no memory of the wiring going to batteries.

So providing the alternator wire is the solitary wire to the terminal it will be accurate.

 

What you are interested in is the current going into the battery NOT the current (amps) coming out of eh alternator. With no loads switched on both readings should be all but identical but as soon as you turn an electrical load on the alternator will be producing more current than is going into the batteries.The proper way is to measure it at one of the main battery leads very close to the batteries but not on a battery interlink.

[valrene9600]

No it wont be, even if it goes straight from the alternator to the battery terminal there will be other cables running from that terminal feeding other circuits

 

I'll check when back allows access to engine hole. With four batts. maybe I can move any extra wires to another terminal.

[Tony Brooks]

I'll check when back allows access to engine hole. With four batts. maybe I can move any extra wires to another terminal.

 

Any extra wires on the battery positive are likely to be permanent feeds for things like car radio memory or bilge pump. maybe another thick one for an inverter. If the inverter and bilge pump are turned off you can ignore any drain to a radio, it will only be few one thousandths of an amp. Do not go moving wires about, to do so without knowing what the wires are may introduce a charging and discharging imbalance leading eventually to further problems..

[valrene9600]

What you are interested in is the current going into the battery NOT the current (amps) coming out of eh alternator. With no loads switched on both readings should be all but identical but as soon as you turn an electrical load on the alternator will be producing more current than is going into the batteries.The proper way is to measure it at one of the main battery leads very close to the batteries but not on a battery interlink.

So if EVERY thing is off(loads) then a reading around the cable woUld be accurate even if other cables were on same terminal. For convenience I guess re arranging other cables would be best so normal boat living could prevail.

Any extra wires on the battery positive are likely to be permanent feeds for things like car radio memory or bilge pump. maybe another thick one for an inverter. If the inverter and bilge pump are turned off you can ignore any drain to a radio, it will only be few one thousandths of an amp. Do not go moving wires about, to do so without knowing what the wires are may introduce a charging and discharging imbalance leading eventually to further problems..

Understood.

[Paul C]

It needs a diagram to easily explain.......I'll try to come up with one.

 

 

 

Apologies for the quickly-drawn picture

 

Simple answer: B or C, NOT A!!!

 

I suspect your wiring near the battery +ve terminal is such that you could easily get the clamp ammeter to position A, but position B (note that it has JUST ONE connection to the terminal - in reality the blob for connections would probably be on the battery terminal itself, with >1 wire coming off it) would be all but impossible to achieve without rearranging the wiring.

 

A better location would be in the negative (position C) but I suspect the same issue of multiple connections on a battery terminal is there too. It would be easier to alter the wiring to provide the single wire which can be meaningfully measured. Note that the diagram, for simplicity, omits items such as fuses and isolation switches etc.

 

Another option - but you must be disciplined - is to SWITCH EVERYTHING OFF and then measure the tail current at eg location A. You MUST switch everything off though, if not then its meaningless. Also its quite possible (eg if you had solar power) that you have 2 "charging" connections, the same issues come in here - you must measure the stuff, and 100% of the stuff, going into the battery.

[valrene9600]

Sorry Terry for taking over your thread but hopefully you are learning as well.

Come back and see if the good forum members can help you further before hour holiday.