Generator

[ditchcrawler]

I am a bit lost, you were charging with the engine, first at highish reves and then several hours at lower revs, but then you say they were on float. are you using some kind of charger?

[Timx]

I am a bit lost, you were charging with the engine, first at highish reves and then several hours at lower revs, but then you say they were on float. are you using some kind of charger?

Hi thanks for asking, charging near 1500 revs ,off the engine, for about three hours then when looked, it had gone on float, so lowered the revs for next couple of hours.I have a solar power display unit and it tells me the stages in the top bit.Its a victron charger with smart meter and mppi controller to two solar panels.I am sure there is information on there to help my charging regime, but when get to debdale they said they will look at my batteries, so hopefully then can assess and advise..

Edited November 19, 2016 by Timx

[WotEver]

Hi thanks for asking, charging near 1500 revs ,off the engine, for about three hours then when looked, it had gone on float, so lowered the revs for next couple of hours.I have a solar power display unit and it tells me the stages in the top bit.Its a victron charger with smart meter and mppi controller to two solar panels

There's some serious confusion here Tim.

 

An alternator doesn't switch to float. An alternator spinning at a high enough speed and connected to heavily discharged batteries will slowly increase its voltage while its current sits at more or less maximum. Once the voltage reaches the regulated value (probably around 14.4V) the voltage will remain static and the current will slowly begin to decrease. When the current has dropped to around 1% of the size of the bank, and/or when it hasn't decreased any further over a period of about 45 minutes you can consider the batteries to be fully charged.

 

Oh, the first stage (rising voltage and max current) is commonly called 'Bulk'. The second stage (fixed voltage and reducing current) is commonly called 'Absorption'.

[Richard10002]

Hi thanks for asking, charging near 1500 revs ,off the engine, for about three hours then when looked, it had gone on float, so lowered the revs for next couple of hours.I have a solar power display unit and it tells me the stages in the top bit.Its a victron charger with smart meter and mppi controller to two solar panels.I am sure there is information on there to help my charging regime, but when get to debdale they said they will look at my batteries, so hopefully then can assess and advise..

You need some means of measuring the Amps going into the batteries at any particular time.. easiest way is to fit a NASA BM1 or BM2 at about a hundred quid.

 

3 Hours on an alternator at 1500, followed by a couple of hours at tickover, isnt going to get close to topping up your batteries to 100% SOC. Without much info, you should probably run for 3 hours a day, and for 8 hours once a week.

 

An inverter on 24/7 will draw quite a lot of Ah from the batteries - what is it powering?

[WotEver]

You need some means of measuring the Amps going into the batteries at any particular time.. easiest way is to fit a NASA BM1 or BM2 at about a hundred quid.

Or one of these for £7 (they've gone up a quid in the last week) http://m.ebay.co.uk/itm/171368601158?rmvSB=true&ul_ref=http%3A%2F%2Frover.ebay.com%2Frover%2F1%2F710-53481-19255-0%2F1%3Ftype%3D4%26campId%3D5336432705%26toolId%3D10001%26customId%3Divjvkc6vt50004m600003%26mpre%3Dhttp%253A%252F%252Fwww.ebay.co.uk%252Fitm%252F0-100V-100A-Shunt-DC-Digital-Voltmeter-Ammeter-LED-Amp-Volt-Meter-12v-24v-car-%252F171368601158%26srcrot%3D710-53481-19255-0%26rvr_id%3D1124174896096&_mwBanner=1&ul_noapp=true

[Timx]

There's some serious confusion here Tim.

 

An alternator doesn't switch to float. An alternator spinning at a high enough speed and connected to heavily discharged batteries will slowly increase its voltage while its current sits at more or less maximum. Once the voltage reaches the regulated value (probably around 14.4V) the voltage will remain static and the current will slowly begin to decrease. When the current has dropped to around 1% of the size of the bank, and/or when it hasn't decreased any further over a period of about 45 minutes you can consider the batteries to be fully charged.

 

Oh, the first stage (rising voltage and max current) is commonly called 'Bulk'. The second stage (fixed voltage and reducing current) is commonly called 'Absorption'.

Thank you, I get the float from looking at the control panel off the solar controller panel which has a 5 page read out, one of which says bulk adsorption and finally float, it tends to say float after about three hours,then to me its guess work as to how long float lasts,to fully charge, but I thought I seen amps zero, and I had read look at amps reducing, but anyway if the bank is healthy I thought it would last me more overnight than the accumulated charge of a fridge and the charger, but hopefully iam wrong and not charging enough and I need 8 hours a day, but then again that cant be economic

[WotEver]

You absolutely need an ammeter. You're just guessing otherwise.

[Richard10002]

Charging boat batteries for leisure use is not economic at the best of times. The secret seems to be to maximise the charging Amps at any particular time.

 

I have an inverter charger that I run off a generator via the shorepower input. It charges at 80A if the batteries will take it... gradually decreasing to 3 or 4A, as the batteries reach 100% SOC.

 

My engine alternator seems to provide a max of about 35A, so takes much longer to charge the batteries enough to the point where they are only drawing 3 or 4A and fully charged. If I were cruising 5 or 6 hours a day, every day, it might work OK - but I dont

 

How many Amps does your alternator provide at cruising revs, (1500? 2000? revs, not Amps) ?

[Timx]

You need some means of measuring the Amps going into the batteries at any particular time.. easiest way is to fit a NASA BM1 or BM2 at about a hundred quid.

 

3 Hours on an alternator at 1500, followed by a couple of hours at tickover, isnt going to get close to topping up your batteries to 100% SOC. Without much info, you should probably run for 3 hours a day, and for 8 hours once a week.

 

An inverter on 24/7 will draw quite a lot of Ah from the batteries - what is it powering?

Thank you, the control panel does seem to show a lot of information, but its placed in a cupboard to the right of eyesight, so I need a light and kinked neck to look at it, it does show amps , I think, on different pages that obviously are changing. As I normally travel a lot, I think its been ok, but last two weeks a gammied foot and no partener to help me move, I am sitting about idle. I will get the boat yard to explain what I am looking at, and whether I have under charged/ too old etc,.The eight hours is pertinent as I am not currently doing that, I am probably knackering them and taking undercharge as a reading of knacked batts

[Richard10002]

I dont know enough about solar panels and controllers, but I wouldn't have thought your solar controller would be in the right location to read what is going into the batteries from the alternator... others may be able to clarify ???

 

The shunt for my NASA BM2 has to be between the battery negative and all other negatives in order to read the Amps into and out of the batteries.

[Timx]

Reading this in pub with lap top plugged in, so that helps, thank you,yes I need an ammeter or smartguage, I am guessing, hence my questions., and I don't know how many amps Richard wish I did or what that denotes, but I will find out .Thank you

My impression is that smart controller and victron and mppi controller are all connected to give me a load of info on battery ,but not soc which I can only derive from the voltage

[WotEver]

... but not soc which I can only derive from the voltage

Or a Merlin SmartGauge. A voltmeter will give you a guide when coupled with experience. A SmartGauge gives you a simple readout - 68% charged for instance.

[Alan de Enfield]

My solar controller will only show the 'amps going in' that have been produced by the solar panels.

 

If I am running the engine, the engine the solar panels will not show how many amps are going into the batteries that are supplied by the alternator.

 

If the engine alternator is set at (say) 14.4 volts and the solar controller set at (say) 14v then the solar will 'shut down' and show zero amps being put into the batteries.

 

Its like trying to extrapolate your cars' speed by using the fuel gauge.

 

You need the proper 'kit'.

[Tony Brooks]

 

Thank you, I get the float from looking at the control panel off the solar controller panel which has a 5 page read out, one of which says bulk adsorption and finally float, it tends to say float after about three hours,then to me its guess work as to how long float lasts,to fully charge, but I thought I seen amps zero, and I had read look at amps reducing, but anyway if the bank is healthy I thought it would last me more overnight than the accumulated charge of a fridge and the charger, but hopefully iam wrong and not charging enough and I need 8 hours a day, but then again that cant be economic

 

When the amount of charge the batteries will accept has fallen enough for the voltage to rise to the alternator's regulated voltage it may well be a little higher than whatever the controller thinks it should be. At that point the solar amps should read zero and I would expect the solar controller to switch to float because it thinks the batteries are fully charged.

 

I would not give over much credence to whatever a solar controller said at the best of times and only use it as a guide when there is no other form of charging taking place.

 

I would not even be sure the solar controller controller is not doing some form of adaptive charging routine and we know that is often far from correct in that it drops to float early.

 

I also do not understand "accumulates charge of s fridge and charger" - fridges do not charge - they discharge batteries.

 

I doubt any form of battery charging for domestic use is "economic" although solar comes close but it has to be done and if it is not done well enough you destroy batteries and new battery banks every few months/weeks is also not economic so you take your pick of the least evil.

 

Once you have a way of RELIABLY establishing that the batteries are as fully charged as you can get them then if they still discharge too far over night it either means the bank is not large enough for your use or, far more likely, that they are heavily sulphated because of persistent under charging.

 

 

[ditchcrawler]

Thank you, I get the float from looking at the control panel off the solar controller panel which has a 5 page read out, one of which says bulk adsorption and finally float, it tends to say float after about three hours,then to me its guess work as to how long float lasts,to fully charge, but I thought I seen amps zero, and I had read look at amps reducing, but anyway if the bank is healthy I thought it would last me more overnight than the accumulated charge of a fridge and the charger, but hopefully iam wrong and not charging enough and I need 8 hours a day, but then again that cant be economic

But you are getting your charge from the engine driven alternator not the solar panels via the controller so that would probably read zero amps but you may still have 10 or 15 going in from the alternator.

[Timx]

My solar controller will only show the 'amps going in' that have been produced by the solar panels.

 

If I am running the engine, the engine the solar panels will not show how many amps are going into the batteries that are supplied by the alternator.

 

If the engine alternator is set at (say) 14.4 volts and the solar controller set at (say) 14v then the solar will 'shut down' and show zero amps being put into the batteries.

 

Its like trying to extrapolate your cars' speed by using the fuel gauge.

 

You need the proper 'kit'.

Yes thank you, think looking at the controller read out is probably confusing me, but it does give the same voltage read out as what shows on the volt meter outside of the cupboard door enclosing the victron and electrics ect, also from a volt meter plugged into a 12v socket.

[Tony Brooks]

Yes thank you, think looking at the controller read out is probably confusing me, but it does give the same voltage read out as what shows on the volt meter outside of the cupboard door enclosing the victron and electrics ect, also from a volt meter plugged into a 12v socket.

 

It should do but that is volts and if it is showing a typical float voltage of about 13.4 to 13.6 with the alternator running then either the batteries are very far from charged or the alternator is faulty.

 

I suspect the solar controller shows float mode by an LED and my advice is to ignore it when alternator or charging with a proper battery charger. It is likely to confuse.

[Timx]

 

 

 

When the amount of charge the batteries will accept has fallen enough for the voltage to rise to the alternator's regulated voltage it may well be a little higher than whatever the controller thinks it should be. At that point the solar amps should read zero and I would expect the solar controller to switch to float because it thinks the batteries are fully charged.

 

I would not give over much credence to whatever a solar controller said at the best of times and only use it as a guide when there is no other form of charging taking place.

 

I would not even be sure the solar controller controller is not doing some form of adaptive charging routine and we know that is often far from correct in that it drops to float early.

 

I also do not understand "accumulates charge of s fridge and charger" - fridges do not charge - they discharge batteries.

 

I doubt any form of battery charging for domestic use is "economic" although solar comes close but it has to be done and if it is not done well enough you destroy batteries and new battery banks every few months/weeks is also not economic so you take your pick of the least evil.

 

Once you have a way of RELIABLY establishing that the batteries are as fully charged as you can get them then if they still discharge too far over night it either means the bank is not large enough for your use or, far more likely, that they are heavily sulphated because of persistent under charging.

 

 

 

I was referring to the accumulated charge the fridge, water pump and inverter/charger was taking during the night when everything else was off. Thanks I am obviously reading things I do not understand from the control panel on the mppi controller and possibly making false assumptions. it shows basically bulk charge for about an hour then absorption for two hours then goes to float, which I was leaving for an hour or two.After all that it falls to 12.5 after an hour or so after charging and 14 hours later 12.2 or .1 as it was this morning, only draw being the inverter, fridge and pump.Hence I think there knackered having listened as best I can. So Tuesday gonna have someone from the local marina look at them.

[Timx]

Yes again , thanks to all contributors, I will report back when its been properly assessed,but if the readings are correct than 660ah of batteries should not be getting to 50pc with only that amount coming out, but, they are old and hopefully I have learnt and will not kill new ones if needed.

I am only going off the readings I have taken , which is highly unreliable.

The batteries have not let me down at all, and I didn't realise I had a problem until I started looking with uneducated eyes, so hopefully they will tell me the readings are wrong, and I will put my spade away forever.

[Tony Brooks]

It certainly sounds as if the batteries have had it but unless there is a shorting cell in one the marina may not have the instruments/knowledge to find sulphated batteries - especially in they are sealed. For otherwise good but sulphated batteries the test you have done with the solar is probably the easiest although using a hydrometer should be more conclusive.

 

When I moored at a different marina I had a fellow boater tearing his hair out with battery problems although the marina had said they were OK. A few minutes with a hydrometer identified two batteries with a shorted cell.

 

The problem is too many are either only using a voltmeter or a High Rate Discharge tester that is designed for 40Ah ish car batteries not 110Ah boat batteries. Such a tester may well pass a failing battery as good because the load it applies is not high enough. Even if it is the correctly calibrated tester it can still show a faulty battery if they are not well charged at testing.

 

I am just posting this in case they pass the batteries yet you still have trouble.

 

Also, as you learn you might want to do hydrometer tests on the batteries to assess their condition and state of charge. You can not do this if you are sold any form of sealed battery.

[MtB]

 

Also, as you learn you might want to do hydrometer tests on the batteries to assess their condition and state of charge. You can not do this if you are sold any form of sealed battery.

 

 

 

Tony, as an aside how do the results of a hydrometer reveal the condition of a battery, other than the state of charge please?

 

I ordered one a few days ago and looking forward to learning to use it and interpret the results.

[WotEver]

 

 

Tony, as an aside how do the results of a hydrometer reveal the condition of a battery, other than the state of charge please?

 

I ordered one a few days ago and looking forward to learning to use it and interpret the results.

Different Tony but anyway... two ways.

 

1. As a battery ages the 'fully charged' state will not read the same Specific Density as a new battery. There's too much unconverable hardened sulphate to convert back to acid.

 

2. One or more cells will show a marked difference in SD than the others which an equalisation charge doesn't fix.

[Tony Brooks]

And coloured electrolyte means the plates in that cell have shed material so may well be shorting.

 

To amplify WotEver's point 2.

 

With a fresh battery the state of charge shown by the rested voltage and the hydrometer reading should be all but the same. As the cells sulphate the two indications drift further and further apart because sulphur from the acid is locked into the sulphate on the plates giving a lower relative density/specific gravity.

[peterboat]

I thought the OP said the batteries are AGMs ? which are definitely sealed mine when they became knackers started to bulge a bit

[WotEver]

I thought the OP said the batteries are AGMs ? which are definitely sealed mine when they became knackers started to bulge a bit

Well he can use this info on his nice new full traction batteries when he replaces them then

 

Right now what he needs is an ammeter.