16.8V charger for equalising Trojans?

[nicknorman]

When my cheapo leisure batteries fell to 50% capacity after 6 month’s leisure use, it was suggested on here the stratification might be the cause. I therefore removed each one onto the towpath and shook/tilted/wobbled each one vigorously for a long time. The result was ... absolutely no change.

[MtB]

9 minutes ago, nicknorman said:

When my cheapo leisure batteries fell to 50% capacity after 6 month’s leisure use, it was suggested on here the stratification might be the cause. I therefore removed each one onto the towpath and shook/tilted/wobbled each one vigorously for a long time. The result was ... absolutely no change.

 

You obviously weren't charging them properly!

[smileypete]

5 minutes ago, nicknorman said:

When my cheapo leisure batteries fell to 50% capacity after 6 month’s leisure use, it was suggested on here the stratification might be the cause. I therefore removed each one onto the towpath and shook/tilted/wobbled each one vigorously for a long time. The result was ... absolutely no change.

I think your problem is right there....

Besides, stratification may go hand in hand with sulphation, and there's no quick cure for that.

If people want to ignore Trojans expert advice for their own batteries, that's fine by me.

[nicknorman]

5 minutes ago, Mike the Boilerman said:

 

You obviously weren't charging them properly!

No, I was charging them fine. On shore power for 75% of the time, and stuffed with charge by my enormous 175A belted beast in between. It’s just that dual purpose leisure batteries are inherently crap!

Exactly the same treatment sees my lovely beautiful fantastic Trojans still at their peak.

1 minute ago, smileypete said:

I think your problem is right there....

Besides, stratification may go hand in hand with sulphation, and there's no quick cure for that.

If people want to ignore Trojans expert advice for their own batteries, that's fine by me.

At least I HAVE Trojans, so I might know what I’m talking about.

[smileypete]

2 minutes ago, nicknorman said:

At least I HAVE Trojans, so I might know what I’m talking about.

Wel I'm glad you HAVE Trojans now and are happy.

[nicknorman]

2 minutes ago, smileypete said:

Wel I'm glad you HAVE Trojans now and are happy.

Me 2.

[WotEver]

15 minutes ago, nicknorman said:

Me 2.

Me 3

Well, it IS Christmas. 

[smileypete]

12 hours ago, Keeping Up said:

The technical support people at Varta advised me to remove the batteries from the boat once a month and "shake them about a bit" to avoid stratification. Not the most useful advice really.

To be fair they also suggested charging up to a higher than normal voltage, which seemed to work IIRC (which I also did suggest a number of times earlier on in the topic. :))

These days boaters in general want the cheapest batts that don't need any maintenance, that can also be charged with a bog standard alternator or charger. No easy answer there I'm afraid...

At least a decent solar setup largely takes care of things for much of the year when boats are used the most, so that's a big step forward.

[MtB]

Yes a couple of solar panels in summer and a marina mooring with shoreline for winter is actually the best solution for people who want their boat and it’s batteries to be ‘plug and play’ (to coin a term). 

[smileypete]

10 hours ago, nicknorman said:

No, I was charging them fine. On shore power for 75% of the time, and stuffed with charge by my enormous 175A belted beast in between. It’s just that dual purpose leisure batteries are inherently crap!

Exactly the same treatment sees my lovely beautiful fantastic Trojans still at their peak.

At least I HAVE Trojans, so I might know what I’m talking about.

IIRC the cheapos started to work better with careful charging at higher than normal charge voltages.

Agree that leisures developed for other large markets may fail somehow when used in the much smaller narrowboat market, especially the 'el cheapest' that may fail miserably at both anyway.

Edited December 24, 2017 by smileypete

[MtB]

Unless you are nicknorman of course, in which case you can still wreck a set in six months, even with 75% of that on the shoreline! 

[smileypete]

11 minutes ago, Mike the Boilerman said:

Unless you are nicknorman of course, in which case you can still wreck a set in six months, even with 75% of that on the shoreline! 

Well he started with Plan A and has now moved to Plan B, (via some Plan B methods on Plan A batteries.) That's not a bad way to go really.

In your case it was Plan B/C batteries with mostly Plan A methods, and didn't really pan out sadly. Hopefully now fully familiar with Plan B methods, which can be used on Plan B batts when the time comes.

[WotEver]

11 hours ago, smileypete said:

If people want to ignore Trojans expert advice for their own batteries, that's fine by me

If only their advice were consistent...

From one document we have, under general advice:

Many experts recommend that batteries be equalized periodically, ranging anywhere from once a month to once or twice per year. However, Trojan only recommends equalizing when low or wide ranging specific gravity (>0.030) are detected after fully charging a battery.

And then later in the same document, referring to Solar charging:

Many charge controllers have equalization settings that you can set to help ensure the health of your batteries. Equalize your batteries at least once per month for 2 to 4 hours, longer if your batteries have been consistently undercharged.

Perhaps they have a specific reason for stating that Solar charged installations should be equalised more often? Perhaps they envisage that such installations are more likely to be static and therefore more likely to suffer stratification than a battery on a vibrating boat? Unfortunately they don’t explain their reasoning for the contradictions so we’re simply left with conflicting advice within a single document.

Their recommended charge voltages also differ from document to document.

http://www.trojanbattery.com/tech-support/battery-maintenance/

[nicknorman]

20 minutes ago, WotEver said:

If only their advice were consistent...

From one document we have, under general advice:

Many experts recommend that batteries be equalized periodically, ranging anywhere from once a month to once or twice per year. However, Trojan only recommends equalizing when low or wide ranging specific gravity (>0.030) are detected after fully charging a battery.

And then later in the same document, referring to Solar charging:

Many charge controllers have equalization settings that you can set to help ensure the health of your batteries. Equalize your batteries at least once per month for 2 to 4 hours, longer if your batteries have been consistently undercharged.

Perhaps they have a specific reason for stating that Solar charged installations should be equalised more often? Perhaps they envisage that such installations are more likely to be static and therefore more likely to suffer stratification than a battery on a vibrating boat? Unfortunately they don’t explain their reasoning for the contradictions so we’re simply left with conflicting advice within a single document.

Their recommended charge voltages also differ from document to document.

http://www.trojanbattery.com/tech-support/battery-maintenance/

Similarly there are different recommended charging and equalising voltages depending on which of their published documents you read.

[smileypete]

No harm in asking Trojan what's best , one of the advantages of buying a premium brand of batts should be access to a good technical support department.

Sounds like the second bit of advice is a ballpark estimate of when EQ may be needed, maybe the document has evolved over time and the new paragraph for solar doesn't quite jive with what's there already.

U.S. Battery have some good information on their website regarding charging, I expect their golf cart batts are somewhat similar to Trojans.

I don't know the specifics of their charging but I'd want to see some modest bubbling at least at the end of charge or EQ, especially in winter. Probably the best charging profile is beyond the capability of marine chargers, so a compromise involving a bit more EQ may be needed.

Also I wouldn't assume that the small amount of vibration caused by a boat engine is enough to prevent all stratification, though it may help some.

Edited December 24, 2017 by smileypete

[MtB]

On 22/12/2017 at 18:49, nicknorman said:

I doubt you’ll find regulated 12v chargers that go over 16v. 15.5v is plenty most of the time, maybe 16v if the batteries are very cold. If you charge the Trojans properly they will rarely if ever require equalising.

 

Indeed. The Trojan User Guide (page 19, table 4) says bulk charge at 14.82v then absorption at 14.10 to 14.70v, which makes little sense to me. Surely bulk charge is by definition lower than the set voltage, then absorption begins when the selected charge voltage is reached and stable. Do Trojan really mean it when they say the absorption voltage must be lower than the bulk charge voltage?

These voltages are however for charging at 25 degrees C. On a cold day when the batts are down at say 5C, the Trojan advice on temperature compensation changes these values to a bulk charging voltage of 15.42v and absorption at 14.7v to 15.4v.

In addition they recommend applying a 'finish charge' of 16.2v at 25C, which temperature compensated for batts at 5C is 16.8v. Same value for equalising. This I imagine is why Richard is seeking a 16.8v charger.

[WotEver]

19 minutes ago, smileypete said:

I don't know the specifics of their charging but I'd want to see some modest bubbling at least at the end of charge or EQ, especially in winter.

Most (all?) of their published optimum charge profiles show a quite steep rise in charge voltage for the last few percent, which is something that I have never seen available in any charger, marine or otherwise. 

[WotEver]

2 minutes ago, Mike the Boilerman said:

The Trojan User Guide (page 19, table 4) says bulk charge at 14.82v then absorption at 14.10 to 14.70v, which makes little sense to me

It makes no sense at all. The very definition of bulk charge is that it’s current limited until the charger reaches absorption voltage, at which point it continues as absorption (obviously). This is clearly shown on the graph beneath that table. I don’t understand why they would state a voltage for a current-limited stage.

Link to the guide:

http://www.trojanbattery.com/pdf/TrojanBattery_UsersGuide.pdf

[MtB]

On 22/12/2017 at 18:42, WotEver said:

Removal of power source resulting in a factory reset?

 

No its not that. That happens every time I turn the genny off. Its something I only need to do occasionally. On reflection I think it is selecting the equalise function. This erases the custom settings IIRC. 

[WotEver]

1 hour ago, Mike the Boilerman said:

 

No its not that. That happens every time I turn the genny off. Its something I only need to do occasionally. On reflection I think it is selecting the equalise function. This erases the custom settings IIRC. 

Makes sense I guess. Sub-optimal but logical

[nicknorman]

1 hour ago, WotEver said:

It makes no sense at all. The very definition of bulk charge is that it’s current limited until the charger reaches absorption voltage, at which point it continues as absorption (obviously). This is clearly shown on the graph beneath that table. I don’t understand why they would state a voltage for a current-limited stage.

Link to the guide:

http://www.trojanbattery.com/pdf/TrojanBattery_UsersGuide.pdf

No, this is normal practice - the bulk voltage is set higher than the absorb voltage. Of course the bulk charging process doesn’t actually reach the set bulk voltage until the end of the bulk phase - it gradually increases towards it as the batteries’ current demand decreases. The charger reaching the set bulk voltage is one of the triggers for it to switch to absorb mode at a slightly reduced voltage. I don’t really know why it should be like that but chargers I’ve seen all have a higher stated bulk voltage than absorb voltage. And let’s remember the whole bulk vs absorb thing is a bit fanciful - the gain on the regulation is soft so it’s not as though maximum charger output is maintained up to the moment the bulk voltage is hit - the regulation curve is much softer than that.

[WotEver]

7 minutes ago, nicknorman said:

No, this is normal practice - the bulk voltage is set higher than the absorb voltage. Of course the bulk charging process doesn’t actually reach the set bulk voltage until the end of the bulk phase - it gradually increases towards it as the batteries’ current demand decreases. The charger reaching the set bulk voltage is one of the triggers for it to switch to absorb mode at a slightly reduced voltage. I don’t really know why it should be like that but chargers I’ve seen all have a higher stated bulk voltage than absorb voltage. And let’s remember the whole bulk vs absorb thing is a bit fanciful - the gain on the regulation is soft so it’s not as though maximum charger output is maintained up to the moment the bulk voltage is hit - the regulation curve is much softer than that.

So what it’s saying, to quote Trojan’s figures, is that you run constant current until the voltage reaches 14.82V at which point the voltage drops to 14.7?

What’s the point?

As you say, the changeover is hardly a ‘switch’; the knee is far softer than that, and the charger doesn’t really need to do anything anyway. It doesn’t ‘switch’ to absorption, it simply regulates its output at 14.7V (or whatever) once it’s able to. 

Trojan’s charging graph doesn’t show any such overshoot either, it simply shows the voltage slowly increasing to 2.35-2.45V per cell (14.1V - 14.7V). 

[nicknorman]

23 minutes ago, WotEver said:

So what it’s saying, to quote Trojan’s figures, is that you run constant current until the voltage reaches 14.82V at which point the voltage drops to 14.7?

What’s the point?

As you say, the changeover is hardly a ‘switch’; the knee is far softer than that, and the charger doesn’t really need to do anything anyway. It doesn’t ‘switch’ to absorption, it simply regulates its output at 14.7V (or whatever) once it’s able to. 

Trojan’s charging graph doesn’t show any such overshoot either, it simply shows the voltage slowly increasing to 2.35-2.45V per cell (14.1V - 14.7V). 

I don’t really know what the point is, but it is normal. For example the standard voltages on our Mastervolt Combi are 14.6 bulk, 14.45 absorb. Something to do with batteries!

Perhaps it’s simply a recognition of the softness of the regulation. If the bulk voltage was set to the same as absorb, the current towards the end of the bulk phase would be a little less due to the lower voltage.

Anyway, IMO people get hung up on the differences between bulk and absorb when in reality there is no clear differentiation. Both phases are just pumping current into the battery!

Edited December 24, 2017 by nicknorman

[WotEver]

21 minutes ago, nicknorman said:

Perhaps it’s simply a recognition of the softness of the regulation. If the bulk voltage was set to the same as absorb, the current towards the end of the bulk phase would be a little less due to the lower voltage.

That makes sense. With the soft knee I guess it’s probable that the charger would take an awful lot longer to get the charge into the batteries if it didn’t start off a little ‘harder’. 

[Richard10002]

2 hours ago, Mike the Boilerman said:

.In addition they recommend applying a 'finish charge' of 16.2v at 25C, which temperature compensated for batts at 5C is 16.8v. Same value for equalising. This I imagine is why Richard is seeking a 16.8v charger.

That will be the reason

I wasn’t certain, but recalled 16.8V from somewhere.

If 16.8V isn’t available, the Victron with 16.2V may be a good one to go for. I like the idea of sitting in my fat backside in the lounge, and setting or resetting the mode via Bluetooth.

At the moment, once in absorption, I have to set an alarm for an hour, then get up and turn the charger on and off, otherwise I can find it’s been on trickle for a few hours, despite the batteries only being partly charged.