Refractometer

[ralphclaydon]

Thanks everyone for all your help!

I am learning!!!!

 

Keeping up

Thanks for those SG readings, According to Trojans you can not have readings that high! Goes to prove that you can not trust the people who manufacture the things.

 

Nick

I thought my prayers may have been answered with the mention of the C Tek battery charger, but i think i can see your reasons why not!

I think that the Bench power supply would be too technical for me to confidently use !

 

 

I don't think i will be in touch with Trojan again!

[nicknorman]

Hi nick

Would a power supply like that be ok to run from an inverter Genny ?

Well that's a good question, but I don't think there is an answer because it would depend on the inverter genny and the particular power supply. I suspect you would only be able to find out by trial and error, however it's also worth bearing in mind that adding a resistive load such as a large incandescent lightbulb can sometimes help to stabilise the mains voltage waveform coming out of such things.

[smileypete]

Thanks for those SG readings, According to Trojans you can not have readings that high! Goes to prove that you can not trust the people who manufacture the things.

 

Are the levels correct though? I wouldnt' be surprised if they were a bit low.

 

Should be on their website, someone may have a link to the page. From memory the correct level is 1/8" from the bottom of the 'fill well', to be read after the batts are fully charged.

 

For suggestions on how best to eq them, would help to know whether there is a shoreline or solar power available or not.

 

There's some good safety precautions (and oodles of info) at The Battery FAQ:

 

http://batteryfaq.org/

 

cheers, Pete.

~smpt~

Edited February 17, 2015 by smileypete

[nicknorman]

Nick

I thought my prayers may have been answered with the mention of the C Tek battery charger, but i think i can see your reasons why not!

I think that the Bench power supply would be too technical for me to confidently use !

 

I don't think the Ctek should be totally ruled out, just that it is a rather expensive and sub-optimal solution. If you do go that way, I would suggest getting the larger one and installing it in place of your current charger for use all the time, rather than just for equalising.

 

Like so many things, once you had used the bench power supply once, you would wonder what all the fuss was about! Do you perhaps know someone who could help you out the first time?

[ralphclaydon]

Hi

I don't have anybody who could help me,

 

 

You say about getting a large one and replacing my Sterling.(Bearing in mind the sterling is 10 years old!) If i went down that route which ctek charger would you recommend?

Would this be simple to wire in?

Another idea!

Tell me if i am talking rubbish! but what about this idea to de sulphate my batteries every month or so!

 

If i bought a MXS 25 and just clipped it to my Trojan battery bank , Having turned my Sterling battery charger off! Leaving MX25 on till it had de sulphated my batteries at 15.5 Volts. then disconnect , returning to sterling charger?

To me this would save rewiring and messing about in engine room.

 

At the end of the day, which would you consider to be the best way forward?

 

Thank You

Edited February 18, 2015 by ralphclaydon

[nicknorman]

Hi

I don't have anybody who could help me,

 

 

You say about getting a large one and replacing my Sterling.(Bearing in mind the sterling is 10 years old!) If i went down that route which ctek charger would you recommend?

Would this be simple to wire in?

Another idea!

Tell me if i am talking rubbish! but what about this idea to de sulphate my batteries every month or so!

 

If i bought a MXS 25 and just clipped it to my Trojan battery bank , Having turned my Sterling battery charger off! Leaving MX25 on till it had de sulphated my batteries at 15.5 Volts. then disconnect , returning to sterling charger?

To me this would save rewiring and messing about in engine room.

 

At the end of the day, which would you consider to be the best way forward?

 

Thank You

Do you know what the current rating of the sterling is? The MXS25 is the larger of the two mentioned. At 25A it is adequate for a boat primarily plugged into shore power, but for use with a genny to charge "off grid" it is on the small side.

 

Yes you could just clip the MXS25 to the batteries when you wanted to use it, but this is a bit of a messy way of doing it compared to the alternative of installing it properly. Your choice, I guess. You could of course start out that way, and when you get fed up with wires dangling around and an extra bit of kit to store, eventually decide to install it properly. Don't forget to turn off everything on the 12v side of the boat when you do it, since the current output at 15.5v is limited and you can't afford to waste any powering the boat's services.

 

If you do use the MXS25 I think you should trigger the equalisation mode repeatedly so that it is in that mode for several hours (I suspect it will drop out of that mode after 30 mins). Once you have done that, it may subsequently be that 30 mins is enough for a maintenance equalisation if done regularly.

 

Since one of those is pushing £200 I just want to say again that I have no experience of any Ctek chargers, so I am not recommending them, just piggybacking onto what others have suggested. However from reading the spec it seems as though it will be just about adequate for equalising especially if you are on shore power, where the time taken to do these things is not too important.

Edited February 18, 2015 by nicknorman

[Rich]

Ctek recommend their M300 for permanent installation as it come equiped with connection eyes instead of clips as per the MXS25.

 

I am going to email them further and ask about the recond (equalisation) setting to find out if it does need resetting until the SG ceases to rise.

 

I looked into using a bench power supply, there are plenty of offering in Google, and it does seem to need a lot of watching to ensure it is done correctly. This puts it in the same class as having my hair cut, I can always think of something more interesting to do.

 

When I get any more info I will put it on here.

Edited February 18, 2015 by Rich

[smileypete]

Hi nick

Would a power supply like that be ok to run from an inverter Genny ?

 

Do you have solar? An unregulated solar panel may eq batts like Trojans quite nicely.

 

Nick might know the typical current needed as AFAIK he has 4 Trojans.

 

cheers, Pete.

~smpt~

Edited February 18, 2015 by smileypete

[nicknorman]

A well timed question as I am out cruising with fully charged batteries. Setting the voltage to a nominal 15.5v gives, after temperature correction, 15.8v (battery temp is showing 11degC). Within 5 minutes the current has fallen to 3.5A which is less than I would have thought, but perhaps it woul be more with warmer batteries?

 

Ed: down to 2.4A after 30 mins. Maybe it would be more if they actually needed equalising?

Edited February 18, 2015 by nicknorman

[cuthound]

A well timed question as I am out cruising with fully charged batteries. Setting the voltage to a nominal 15.5v gives, after temperature correction, 15.8v (battery temp is showing 11degC). Within 5 minutes the current has fallen to 3.5A which is less than I would have thought, but perhaps it woul be more with warmer batteries?

Ed: down to 2.4A after 30 mins. Maybe it would be more if they actually needed equalising?

Definately, batteries are chemical devices and react more at higher temperatures. For the type of lead acid batteries that I am most familiar with, VRSLA's, the typical self discharge current is about 4% at 25 degrees C, falling to 1% at 0 degrees C.

I expect all other typical current (tail etc) to behave in a similar manner.

[Boredrider]

To confirm Nick's figures, I equalised my 4 T105's yesterday, using my solar (Outback 60 MPPT, 4 X 100W semi-flexible panels). At 15.5 V the charge current started at 4.8 amps and after 30 mins it was down to 2.8 amps. It stayed at that level for the rest of the three hour equalisation. The batteries were fully charged at the start of the process, and had been on float (13.4) since late October.

[dmr]

A well timed question as I am out cruising with fully charged batteries. Setting the voltage to a nominal 15.5v gives, after temperature correction, 15.8v (battery temp is showing 11degC). Within 5 minutes the current has fallen to 3.5A which is less than I would have thought, but perhaps it woul be more with warmer batteries?

 

Ed: down to 2.4A after 30 mins. Maybe it would be more if they actually needed equalising?

 

I see Much higher currents when equalising. This is in part because I usually start the equalisation before they are really fully charged.

A second factor is that my Trojans are now 3.5 years old and have worked very hard (off grid CC'ing). The water consumption and tail current are noticeably higher than when they were new.(this is expected)

I would suggest getting an equalisation device than can deliver at least 10 amps, and probably 15, otherwise it may proved inadequate as the batteries age.

 

3.5 years! never used to get more than a year from cheapo leisures.

 

............Dave

[smileypete]

 

I see Much higher currents when equalising. This is in part because I usually start the equalisation before they are really fully charged.

A second factor is that my Trojans are now 3.5 years old and have worked very hard (off grid CC'ing). The water consumption and tail current are noticeably higher than when they were new.(this is expected)

I would suggest getting an equalisation device than can deliver at least 10 amps, and probably 15, otherwise it may proved inadequate as the batteries age.

 

What 's the normal 'tail current' when receiving a full charge?

 

To my mind eq does the following:

 

1. Mix electolyte where stratified

2. Bring low cell SGs up to maximum

3. Reduce or remove stubborn sulphation

 

So I wonder if a lesser eq current could do at least 1. and 2, even if 15.5v isn't quite reached.

 

Maybe a proper(!) desulphator could help with 3.

 

cheers, Pete.

~smpt~

[dmr]

I reckon you are right, a lower current (& voltage) will do the job but take longer.

Stubborn sulphation is probably the difficult one and may need more than 15.5v or otherwise take a VERY long time.

 

If the equalisation is done by running an engine/generator then its good to do at as quickly as possible.

If the plan is to take a battery out of service then a lower current is probably ok, but if its done on the whole bank in situ then the power supply/charger also has to meet the house demand.

 

Not sure about "proper" de-sulphators, do you mean the pulse things that "resonate the sulphate crystals" ? I think they might have a bit of snake oil inside them.

 

.............Dave

[smileypete]

Was thinking more of an unregulated solar panel...

 

So, charge with genny in the morning then let the sun do the work, the longer time taken isn't a problem. If the house bank needs to be used, there's various ways round that depending on circumstances. Maybe small short term loads like water pumps wouldn't make a lot of difference overall.

 

With desulphators, seems to me the crystal resonance thing is probably marketing spiel, but I do think decent pulse charging will remove sulphate a lot better than trickle charging or normal charging:

 

I doubt a weak desulphator will do much good in the shorter term, unfortuately a lot of commercial ones are like that. There's a whole forum dedicated to the things:

 

http://leadacidbatterydesulfation.yuku.com

 

cheers, Pete.

~smpt~

Edited February 19, 2015 by smileypete

[Rich]

Like so many things, once you had used the bench power supply once, you would wonder what all the fuss was about! Do you perhaps know someone who could help you out the first time?

What amperage should a bench power supply unit be set at to equalise a bank of 4 x T105s (connected to give 12 volt) having set the voltage to 15.5?

 

There is a fair amount of info about using PSUs for equalising but if any mention is made of amps it is to set it to something suitable and therefore not very helpful?

[nicknorman]

What amperage should a bench power supply unit be set at to equalise a bank of 4 x T105s (connected to give 12 volt) having set the voltage to 15.5?

 

There is a fair amount of info about using PSUs for equalising but if any mention is made of amps it is to set it to something suitable and therefore not very helpful?

The batteries will determine the current they take at a specific voltage. So you don't set a current, but you can set a maximum current (current limit function). As we have seen, provided you start with fully-charged batteries in good condition the current is not that high -under 5A and maybe half that.

 

For the power supply I linked to I would be inclined to set the maximum current limit (5A). If after a while the supply was still in constant current mode (ie unable to give enough current to raise the voltage to 15.5v) then you would have to split the bank into 2, but my recent test shows it should be fine with 450AH of T105s.

 

I have read recently that some supplies are not designed to be used in current limit mode for long periods, so if in doubt the other approach is to reduce the set voltage until the supply can meet the current demand, and then subsequently hope to be able to gradually increase the voltage keeping within the max current.

 

"Proper" chargers with built in equalisation mode seem to have quite a low current limit in EQ mode, for example I think it is 6A or thereabouts on my otherwise 100A Mastervolt, but this is to protect against thermal runaway. I have never noticed the batteries getting significantly warm during equalisation - you aren't really putting enough power into them - but I guess if the batteries were already hot (ie hot country) there might be an increased risk of thermal runaway (ie increasing current being taken at increasing temperature) ence the low max current in this mode.

 

Anyway, unless your bench power supply is huge there is no chance of thermal runaway.

 

Edit: oh and bear in mind the 15.5v is the nominal value at 27degC, it needs to be more at lower temperatures.

Edited February 21, 2015 by nicknorman

[Rich]

 

I have read recently that some supplies are not designed to be used in current limit mode for long periods,

 

 

Edit: oh and bear in mind the 15.5v is the nominal value at 27degC, it needs to be more at lower temperatures.

Thanks Nick, will the model you quoted have problems with being in current limit mode for long periods, and, (there's always an and or a but) do you know of a table giving temperature/voltage as this is the first I have seen of this? Would this be ambient temperature or battery temp?

 

I feel a purchase coming on as with my battery charger, an Sterling, I can disconnect the batteries and use the charger as a power pack thus removing the 15.5 volts from the system.

[nicknorman]

No I don't think the model I have will suffer from being in current limit for long periods, it certainly doesn't say anything to that effect, though I can't promise anything! Anyway, as I mentioned you don't actually have to have it in current limit mode, you can just reduce the voltage a bit until it can maintain that voltage.

 

HOWEVER looking on the Internet just now, folk have had problems with this supply when used as a charger for eg 24v batteries. When you power up the supply, initially the output is switched off. You press a button to turn on the output. However if you connect the battery before doing this, there is a bit of a spark as the battery current rapidly flows into the supply's output capacitors. It is suggested that with higher voltage batteries this inrush current is too much and something blows. Therefore the advice is to turn on the output before connecting the leads, which is somewhat against normal advice. However I don't think doing that is dangerous, what is dangerous is to disconnect the leads at the end of a gassing charge whilst the output is still on, since this can cause a small spark in the presence of hydrogen and oxygen.

 

So, activate the output then connect the leads. Deactivate the output then disconnect the leads.

 

Regarding temperature compensation, for 12v use 30mV per deg C away from 25deg. So for example at 10 deg C, 15.5v becomes 15.95v. This is electrolyte temperature but of course a rested battery is likely to be at ambient temperature if the latter has been steady. Otherwise you will just have to guess, it's not that critical.

Edited February 21, 2015 by nicknorman

[The Lockie]

Not sure if this suggestion is relevant or not,in addition I'm going from memory and that is notoriously unreliable!!

 

Do the sterling par alternator controllers not have an equalisation setting?? Even if they don't they are programmable so would it be possible to increase the output to enable an equalisation charge??. Added advantage that you could equalise whilst cruising!! Just a thought. Probably wrong. Nick whaddya think?

[lexicon]

Does anyone near Leighton buzzard have a refractometer that I could borrow to test my batteries?

[Keeping Up]

Does anyone near Leighton buzzard have a refractometer that I could borrow to test my batteries?

 

You could borrow mine, it's on the boat at Stoke Hammond.

[nicknorman]

Not sure if this suggestion is relevant or not,in addition I'm going from memory and that is notoriously unreliable!!

Do the sterling par alternator controllers not have an equalisation setting?? Even if they don't they are programmable so would it be possible to increase the output to enable an equalisation charge??. Added advantage that you could equalise whilst cruising!! Just a thought. Probably wrong. Nick whaddya think?

I'm not familiar with Sterling alternator controllers but the manual I looked at seemed to have a high voltage cutoff/alarm at 15.5v. I'm sure they will help, by charging at 14.8v or so, but I'm not sure they do a "proper" equalisation charge especially as you need over 15.5v when the battery temperature is less than 25 deg C.

[Sea Dog]

My own charger (part of the mastervolt Combi) does have an equalise mode but it's rubbish. I therefore equalise simply by manually increasing the charging voltage -I'm lucky because I can do that with my Combi.

 

 

Hi Nick, just reading through this thread and noticed this earlier comment you made. I also have a Mastervolt Combi and thought I was rather well placed since it has an equalisation mode. Can you explain why you don't rate it? Is racking up the charging voltage instead pretty self explanatory?

[nicknorman]

Hi Nick, just reading through this thread and noticed this earlier comment you made. I also have a Mastervolt Combi and thought I was rather well placed since it has an equalisation mode. Can you explain why you don't rate it? Is racking up the charging voltage instead pretty self explanatory?

I haven't tried it recently (with the Trojans) but when I tried it with the open wet cells batteries the mode would exit after about 30 mins. If you wanted longer (which you normally do), you had to reactivate it repeatedly. I never worked out why it exited after the minimum time. Too much, or too little current being taken I presume.

 

Anyway I found it vastly simpler to just increase the charge voltage. However you need the right kit to do that, there are basically 2 ways one of which is to fit a Masterview Easy panel and Masterbus interface for the Combi, which is what we have (the Masterview Easy also talks to the Mastershunt, giving SoC based on amp hour counting etc, so I didn't get it just to talk to the Combi).

 

The other way is to get a Combi to USB interface and download the (free) Masteradjust software, then you can change all the Combi's settings including the charge voltage, using a laptop. This second method is cheaper presuming you already have a windows based laptop, the interface is a little over £100 IIRC.