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1 hour ago, Tony Brooks said:

If its noise & vibration that are an issue then an Aquadrive coupling, hospital silencer, exhaust exiting the back (not the side) and soundproofing is, in my view, likely to be more cst effective and far less problematic.

Thanks Tony

You have just added a few more items to look for when viewing boats. I know that I will not find a boat that includes everthing on my wish list but the more information I can find between now and purchase time will probably change this list to something completeley different from where it started.

When it comes to electrical engineering I am no shop egg having been an industrial electrical engineer for the last 30 odd years, PLC control of machines by HMI is what I do but Batteries! they come into play to put on the safety lights when the power fails :)

It will not take me long to come upto speed with battery technology and I'm sure that once I grasp the fundamentals I will be able to come to terms with what is possible.

The last three issues covering the use of Lithium LifePO4 batteries have been very informative has also what I have read from all contributors to this post, and I thank you all.

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1 hour ago, AWETHEAYET said:

So what is the best method of measuring soc? I have re-read posts on voltage levels and "charts" giving potential levels of charge but confusingly they differ, a poster did explain why (sorry if I have not quoted you) so what, if anything can be monitored to give actual soc? or am I over thinking it

The charts differ because they were produced for different designs of battery and probably at different temperatures.  The so called 50% rule is no such thing, it is just a simple to understand way to optimise battery life so "time to recharge" is safely variable by a little, but in any case the best rule for maximum battery life is recharge to full every day but practically 80% or so every day and 100% once or twice a week will be good enough.

 

Anyway you assess when fully charged by tail current at around 14.4 volts. If the charging current at about 14.4 volts has dropped to about 1 to 2% of bank capacity and it has stopped gradually falling the batteries are as fully charged as dam it is to swearing. This means you don't really have to worry about the fully charged rested voltage but 12.7 to 12.8 will be good enough.

 

The recharge ASAP rested voltage s around 12.2 to 12.3 (all rested voltages with no load or charge being applied) but its not that critical, you could go down to 12.1 or even 12V occasionally without noticeable battery damage as long as you recharge promptly.

 

That just leaves a " consider half charged" voltage so you can assess how fast the bank is discharging and again it is not that critical so around 125 volts will do for that.

 

The important things to grasp is fully recharge every day if possible and try not to let the bank drop below around 12.2 volts. Charge until the ammeter stops dropping and is at around 1 to 2% of battery capacity @ around 14.4 volts

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2 hours ago, Tony Brooks said:

 

Member Dr Bob was responsible for those articles.

 

Thanks for the mention Tony but...... @MoominPapa, @peterboat and @Tom and Bex don't get away Scott free. I blame them for everything. The last of the 3 articles is just out now in Canalboat....I've not seen it yet but Peter reports it is out and is all their work! A very good collective effort all made possible by this forum.

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13 hours ago, AWETHEAYET said:

So what is the best method of measuring soc? I have re-read posts on voltage levels and "charts" giving potential levels of charge but confusingly they differ, a poster did explain why (sorry if I have not quoted you) so what, if anything can be monitored to give actual soc? or am I over thinking it

Re-read the first post in this topic. It gives the answer to this question. 

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I'd recommend fitting a low battery voltage automatic cut off switch , because as we learnt the hard way if you leave some thing on and go away when you come back your whole battery bank will drain to nothing and it will never hold a charge again.  The switch is a few quid on eBay or Amazon our battery bank was over £400 to replace. 

 

https://www.ebay.co.uk/itm/12-36V-Battery-Cut-off-Disconnect-Automatic-Switch-Recovery-Protection-Module-iO/143358321331?_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D1%26asc%3D20180213162448%26meid%3D43e7769cf4ac4679a10e46bbdf70af24%26pid%3D100930%26rk%3D1%26rkt%3D12%26mehot%3Dlo%26sd%3D282664246887%26itm%3D143358321331%26pmt%3D1%26noa%3D1%26pg%3D2332490&_trksid=p2332490.c100930.m5375

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2 hours ago, CompairHolman said:

I'd recommend fitting a low battery voltage automatic cut off switch , because as we learnt the hard way if you leave some thing on and go away when you come back your whole battery bank will drain to nothing and it will never hold a charge again.  The switch is a few quid on eBay or Amazon our battery bank was over £400 to replace. 

 

https://www.ebay.co.uk/itm/12-36V-Battery-Cut-off-Disconnect-Automatic-Switch-Recovery-Protection-Module-iO/143358321331?_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D1%26asc%3D20180213162448%26meid%3D43e7769cf4ac4679a10e46bbdf70af24%26pid%3D100930%26rk%3D1%26rkt%3D12%26mehot%3Dlo%26sd%3D282664246887%26itm%3D143358321331%26pmt%3D1%26noa%3D1%26pg%3D2332490&_trksid=p2332490.c100930.m5375

Presumably you can’t connect your battery cable direct to the automatic switch. It would need to activate a relay that could cope with the current from the batteries.

 

I struggle with relays, so have a much more expensive Victron Battery Protect. As Intype, I do have a couple of relays on order to see if I can work out how they work at my late stage of life, (relatively :) ).

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12 hours ago, WotEver said:

Re-read the first post in this topic. It gives the answer to this question. 

Thank you - re-read all posts now got it (basic theory that is) going to play with charger and batery in garage to start looking at hydromiter v refractomiter for measuring SOC.

 

Below is my basic understanding of all your help, I'll probably keep re-reading until it is fully embeded, but have I made a good start?

 

image.png.674159ef0a3135d92df624d6699df2b6.png

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2 minutes ago, AWETHEAYET said:

Thank you - re-read all posts now got it (basic theory that is) going to play with charger and batery in garage to start looking at hydromiter v refractomiter for measuring SOC.

 

Below is my basic understanding of all your help, I'll probably keep re-reading until it is fully embeded, but have I made a good start?

 

image.png.674159ef0a3135d92df624d6699df2b6.png

Are you happy you understand the Bat Volts are the battery voltage after resting and with no solar connected?

Where does the 12.6 come from next to the 25%?

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2 minutes ago, Dr Bob said:

Are you happy you understand the Bat Volts are the battery voltage after resting and with no solar connected?

Where does the 12.6 come from next to the 25%?

Yes quite happy that battery voltage readings are taken when no charge or load pressant and after allowing to rest (3 minutes? don't know where I got that from, something to do with croc clips and explosions). Sorry the 2.6 is a typo should be 2.06.

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12 minutes ago, AWETHEAYET said:

Thank you - re-read all posts now got it (basic theory that is) going to play with charger and batery in garage to start looking at hydromiter v refractomiter for measuring SOC.

 

Below is my basic understanding of all your help, I'll probably keep re-reading until it is fully embeded, but have I made a good start?

 

image.png.674159ef0a3135d92df624d6699df2b6.png

You are quoting rested battery voltage against charger output, that dosent happen,  Absorption will be around 14+ volts. As the Doc said, those percentages/voltages only work on resting batteries.

2 minutes ago, AWETHEAYET said:

Yes quite happy that battery voltage readings are taken when no charge or load pressant and after allowing to rest (3 minutes? don't know where I got that from, something to do with croc clips and explosions). Sorry the 2.6 is a typo should be 2.06.

I would say hours not minutes

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46 minutes ago, Richard10002 said:

I struggle with relays...

A simple relay has 4 connections. Two of them are the coil or ‘activation’ connections. Connect 12V across them and the relay operates. It goes ‘click’. The other two terminals are the ‘switch’. When the relay operates those two terminals are connected together, just like an on/off switch. This is called a Single Pole Normally Open (SPNO) relay because in its ‘normal’ or un-energised state the single set of switching terminals are open circuit - not connected together. 
 

More complex relays have change-over contacts, so when it’s un-energised pins x & y are connected together, then when energised it changes over so that x & y are disconnected and x is now connected to z instead. This is called a SPDT (Single  Pole Double Throw) relay.  

 

Then you can get Double Pole relays, triple pole, four pole etc. 

5 minutes ago, AWETHEAYET said:

after allowing to rest (3 minutes? don't know where I got that from...

Me neither. 
 

Best way to get rid of surface charge and read the rested voltage would be to disconnect all charging sources and turn on the tunnel lamp for 10 minutes. 

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4 minutes ago, ditchcrawler said:

You are quoting rested battery voltage against charger output, that dosent happen,  Absorption will be around 14+ volts. As the Doc said, those percentages/voltages only work on resting batteries.

I would say hours not minutes

Thanks Brian

How many?

6 minutes ago, WotEver said:

Best way to get rid of surface charge and read the rested voltage would be to disconnect all charging sources and turn on the tunnel lamp for 10 minutes

thank you I'll install a lamp when I'm doing my practical learning.

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20 minutes ago, AWETHEAYET said:

Below is my basic understanding of all your help, I'll probably keep re-reading until it is fully embeded, but have I made a good start?

 

image.png.674159ef0a3135d92df624d6699df2b6.png

Not really, sorry. As DC says above, you can’t mix charging voltages with SoC voltages as they’re entirely unrelated.
 

A bulk charge will be a constant current with a slowly increasing voltage until it reaches around 14.4V. The exact voltage depends on your charge source. The absorption charge will remain at 14.4V and you will see the current slowly reducing. When the current has reduced to about 1% or 2% of your total battery capacity (and/or hasn’t reduced for an hour) then the batteries are fully charged. So say 4 to 8 Amps with a 400Ah battery bank. 

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7 minutes ago, WotEver said:

Not really, sorry. As DC says above, you can’t mix charging voltages with SoC voltages as they’re entirely unrelated.
 

A bulk charge will be a constant current with a slowly increasing voltage until it reaches around 14.4V. The exact voltage depends on your charge source. The absorption charge will remain at 14.4V and you will see the current slowly reducing. When the current has reduced to about 1% or 2% of your total battery capacity (and/or hasn’t reduced for an hour) then the batteries are fully charged. So say 4 to 8 Amps with a 400Ah battery bank. 

Sorry WotEver its the way I layed it out on the spread sheet to get my head round it. Yes I do understand that the charging voltage and SOC are two seperate things, and thank you for the additional explination.

I have a cheep battery hydromitor that I am going to play about with on the car battery. If the bugger doesn't start for work on Thursday I'm blaiming you lot :)

 

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1 hour ago, Richard10002 said:

Presumably you can’t connect your battery cable direct to the automatic switch. It would need to activate a relay that could cope with the current from the batteries.

 

I struggle with relays, so have a much more expensive Victron Battery Protect. As Intype, I do have a couple of relays on order to see if I can work out how they work at my late stage of life, (relatively :) ).

You are absolutly right the quoted relay as a carrying current of 30 A. Don't know the typical pull of a narrowboat system but I'm sure its greater than that. Relays I do know about!

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11 hours ago, AWETHEAYET said:

Thank you - re-read all posts now got it (basic theory that is) going to play with charger and batery in garage to start looking at hydromiter v refractomiter for measuring SOC.

 

Below is my basic understanding of all your help, I'll probably keep re-reading until it is fully embeded, but have I made a good start?

 

image.png.674159ef0a3135d92df624d6699df2b6.png

Just to mention that there is no direct correlation between state of charge, and ability to absorb current. Think of the battery plates as sponges, the material at the surface is easy to reach /easy to react, the stuff deep inside is much harder to reach /slower to react.

 

So if you take a battery at 50% SoC and apply a large alternator, let’s say you get 150A charging current. By 75% SoC you will perhaps be getting 75A and by 90%, perhaps 15A. This is because the chemicals deep inside the plate have been discharged, and it takes a long time for the charging reaction to penetrate deep into the plates.

 

But if you take the same battery fully charged, discharge to 90% fairly quickly and then apply the same alternator, you will get an initial charge of around 150A. The current decrease will follow the same shape as before, but over a much shorter time. (Ie the current will decrease much faster). This is because the battery was discharged by reacting the chemicals on or near the surface of the plates, and that reaction is easily and quickly reversed during charge.

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Here's another question regarding solar , if you're using a digital battery charger to boost the charging in the winter day time should you shut off the solar while using the charger to ensure the charger senses the true battery at rest voltage ?

 

I'm thinking that the solar in winter will boost up the battery voltage without actually putting any charge in ?

 

 

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13 minutes ago, CompairHolman said:

if you're using a digital battery charger to boost the charging in the winter day time should you shut off the solar while using the charger

Nope

13 minutes ago, CompairHolman said:

to ensure the charger senses the true battery at rest voltage ?

The charger couldn’t care less what the battery resting voltage is, only what current the battery demands. The voltage is set by the charger. 
 

15 minutes ago, CompairHolman said:

I'm thinking that the solar in winter will boost up the battery voltage without actually putting any charge in ?

The battery at rest voltage can only raise if the charge is raised. Solar in winter won’t do much but if it’s outputting anything then it’s charging the battery. 

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7 minutes ago, CompairHolman said:

Here's another question regarding solar , if you're using a digital battery charger to boost the charging in the winter day time should you shut off the solar while using the charger to ensure the charger senses the true battery at rest voltage ?

 

I'm thinking that the solar in winter will boost up the battery voltage without actually putting any charge in ?

 

 

What's a digital battery charger?

 

Are you talking about a mains driven charger or some form of advanced alternator controller or a Sterling A to B?

 

From the moment a charger starts to charge it can not sense the at rest voltage, only the charging voltage so its no different from any other charge source.  Mains chargers or alternator add ons may use a digital system to do funny things with voltage control but they will be measuring the charging voltage and possibly the rate of voltage change to decide when to drop into float.

 

If any charge source increases the voltage on the battery terminals it MUST put charge in although on a dull day the batteries may want more charge than the solar can provide and this will depress the solar  charging voltage.

 

As stated so often before during the first stage of charging, often referred to as bulk, the battery demand will probably be above the charge source's capabilities. During this phase the current will be at the charge source's maximum with the voltage depressed. As the batteries charge up the current they demand will gradually fall and thus the charging voltage rises to the point at which voltage regulation takes place (often called absorption).

 

In your scenario at first (during bulk) all charge sources will provide their maximum output. As the charging moves to absorption one of the sources' will start regulating the voltage and at that point the source with the lowest set regulator might just shut down. However the batteries will by that time have a fair degree of charge so loosing one source will not make any difference to the charging current because its the batteries that are controlling the charging current, not the charge source.

 

A mains charger will also supply pour domestic loads up to its maximum output so it makes sense to leave it connected and running. Alternator charging costs fuel and engine wear so its best to do engine charging early in the day and leave the solar to complete the job when you only need a very long, low current charge. Just leave the solar connected, it may make no difference to the charging at this time of year but it will not degrade it.

 

 

 

 

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  • 9 months later...

Good post Tony!
This is good info for anyone boating, or new to boating.This’s too specific for the intended audience.
Basically When we are going to charge a battry we have to kept in mind that the best kind of charger on your battery is a three stage charger.
This types of charger are safe, easy to use.
1:Bulk Charge are typically where the heighest voltage and amperage the charegerthe charger is rated for will actually be used. The level of 
charge that can be applied without overheating the battery is known as the battery's natural absorption rat.
2: Absorption Charge are basically use to ditect the voltage and resistance from battry prior to charge.At this point most chargers will maintain a steady 
voltage, while the amperage declines. The lower current going into the battery safely brings up the charge on the battery without overheating it.
3:Float Charge brings the battery all the way through and maintains the 100% state of charge. The voltage will taper down and maintain at a steady 13.2-13.4 volts, which is the maximum voltage a 12 volt battery can hold.
The best kind of charger to use on a battery is a 3 stage smart charger. They are easy to use and worry free. You don't ever have to worry about leaving the charger on the battery for too long. 

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1 minute ago, republicscented said:

Good post Tony!
This is good info for anyone boating, or new to boating.This’s too specific for the intended audience.
Basically When we are going to charge a battry we have to kept in mind that the best kind of charger on your battery is a three stage charger.
This types of charger are safe, easy to use.
1:Bulk Charge are typically where the heighest voltage and amperage the charegerthe charger is rated for will actually be used. The level of 
charge that can be applied without overheating the battery is known as the battery's natural absorption rat.

2: Absorption Charge are basically use to ditect the voltage and resistance from battry prior to charge.At this point most chargers will maintain a steady 
voltage, while the amperage declines. The lower current going into the battery safely brings up the charge on the battery without overheating it
.
3:Float Charge brings the battery all the way through and maintains the 100% state of charge. The voltage will taper down and maintain at a steady 13.2-13.4 volts, which is the maximum voltage a 12 volt battery can hold.
The best kind of charger to use on a battery is a 3 stage smart charger. They are easy to use and worry free. You don't ever have to worry about leaving the charger on the battery for too long. 

 

I very much disagree with the bit in red because any multi-stage charger available in the UK and I strongly suspect the USA have a very nasty habit of dropping to float too early so users think the batteries are fully charged when they are not. This leads to ever an increasing degree of sulphation in the hands of the vast majority of boaters. The only people can use a three stage charger to fully charge their batteries are those that recognise this so turn the charger off for a short while and then back on again when it drops to float. They may have to do this several times per charge cycle to reach fully charged. Also a soon as the charger has dropped to float the charging current (amps) is no longer any use is implying when fully charged.

 

The blue part - a complete misunderstanding of the situation as explained below. The charger is just supplying the maximum current it is capable of. It has nothing to do with overheating the batteries. As  long as you do not exceed the batteries maximum charging voltage they will not overheat and during bulk where the batteries are drawing all the current the charger can provide the charger design reduces the current.

 

Now the part in green - more misinformation. When a charger of ANY sort that has voltage regulation goes into the absorption stage it has nothing to do with detecting the voltage. That was set within the design of the charger. I suggest you really study what our other Tony explained. An alternator or battery charger is going to have its charging voltage dragged down as the charging current rises. All the bulk phase means is the charging current is so high (because the batteries are well discharged) the charging voltage has been dragged down to below the accepted safe and thus regulated charging voltage. As the batteries charge their apparent resistance to the charging current rises so the charging current falls and thus the charging voltage rises. The voltage keeps rising until it more or less reaches the designed maximum so voltage  regulation starts to take place. Once this happens you are into the absorption phase that may take well in  excess of 10 hours to get the batteries fully charged. You note there is no detecting of voltage. Its just when the charging current has fallen enough to allow the charging voltage to reach the regulated voltage designed into the machine.  A three stage charger may well TIME the bulk charge phase (that is the time it takes to go from being turned on until voltage regulation starts) and then uses that time to guess the time needed in absorption which is all too often too short and thus damaging to the batteries. If you do not believe me turn the charger off  as soon a sit drops to float and run the engine at charging speed - see how long t takes for the charging current at 14.4V+ to drop to about 1% of battery capacity.

 

Float charge is just an automatic resetting to the voltage regulator to a lower value such that in theory allows for a charging current to just about keep pace with self discharge and I have never seen a float voltage of 13.2V, more typically its around 13.6 volts. Again I can't see the values in the USA being much different.

 

The other Tony wrote the piece in response to endless instances on here related to battery problems that mainly result from a complete lack of knowledge about batteries and charging. This is not helped by battery monitor makers supplying designs that unless operated by someone who understands all this and adjusts/regularly resynchronises then tell blatant lies and encourages boaters to destroy their batteries.

 

The only way to get the batteries fully charged and minimise sulphation is to understand all that Tony wrote and act accordingly. My advice to others is to ignore your post and study Tony's very valuable piece - then ask for further information/clarification on here. Three stage chargers are good but far from perfect. Thy are very likely to encourage sulphation.

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Bought the boat and replaced the 120 va invertor with a victron 3000 multyplus new bat monitor and colour controller, seller replaced bats with 3 x 120aH maintenance free and a 90 ah starter.

I have set the BM to 360 and left everthing else to factory setting. What else should I consider to change within the system/ programing to give the batteries a "good life" while maintaing electricity to the boat?

HTATBO as a new toy on her phone that instructs me to start the engine, makes a change from putting the kettle on :)

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23 minutes ago, AWETHEAYET said:

Bought the boat and replaced the 120 va invertor with a victron 3000 multyplus new bat monitor and colour controller, seller replaced bats with 3 x 120aH maintenance free and a 90 ah starter.

I have set the BM to 360 and left everthing else to factory setting. What else should I consider to change within the system/ programing to give the batteries a "good life" while maintaing electricity to the boat?

HTATBO as a new toy on her phone that instructs me to start the engine, makes a change from putting the kettle on :)

All you need to do is to fully charge them as often as possible, at the very least, weekly, more often if possible. It’s all in the OP. 

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