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Equalisation charge - is it a waste of time?

Momac

By Momac
in Boat Building & Maintenance

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WotEver Veteran II

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Posted
Posted
22 minutes ago, blackrose said:

Ok, I'll give it another go tomorrow. Would I be better off switching the charger off and trying the bench power supply on it's own?

If the bench psu voltage is higher than the charger’s (and there’s no point using it if it isn’t) then the charger will simply switch off. But the bench psu must be capable of supplying the current demanded by the batteries or it itself may simply shut down.  
 

Having said that, fault-finding would be easier without the charger connected. 

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blackrose Veteran II

blackrose

Posted
Posted (edited)

Ok, I've been fiddling with it this morning and got it to work. Thanks, you were right, I was being too cautious yesterday and just needed to play with it. The battery charger is switched off 

 

I'm getting 16v at 5 amps now. I can only get 16v even though the power supply is meant to go up to 30v? 16amps is fine but I just wondered. My battery monitors are reading 15.6v so I guess there's some voltage drop in the cables? Usually they are spot on. I'll check the voltage at the batteries with a multimeter.

 

I tried turning the amps down but it drops the voltage. It's been like that for about 20 mins. How long should I leave it for?

IMG_20191222_113255_8.jpg

Edited by blackrose
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WotEver Veteran II

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Posted
Posted
Just now, Alan de Enfield said:

Is the battery bubbling vigorously ?

 

I wouldn't leave it more than 1 hour at 16v

Sounds about right. 
 

8 minutes ago, blackrose said:

I can only get 16v even though the power supply is meant to go up to 30v?

The batteries will be limiting it. 
 

 

8 minutes ago, blackrose said:

My battery monitors are reading 15.6v so I guess there's some voltage drop in the cables?

Always possible (probable?), but the psu readout might be inaccurate too. Get thy multimeter out. 

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blackrose Veteran II

blackrose

Posted
Posted (edited)

The battery monitors are correct. They're now reading 15.7v which is the same as the multimeter direct to the batteries. The power supply must be out of calibration as it's now showing 16.1v. 

 

I can't do a proper equalisation charge at 15.7v can I? Trojan recommend 16.2v.

 

Edit: the voltage is slowly climbing. Power supply is now reading 16.2v. battery monitors at 15.8v

Edited by blackrose
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Alan de Enfield Veteran II

Alan de Enfield

Posted
Posted
4 minutes ago, blackrose said:

So shall I wait until it reaches 16.2v, keep it stable at that voltage by reducing the amps and then give it an hour?

I'd give it an hour from when it started showing 15.5v or higher.

 

Different batteries are 'different' but I normally just give my standard FLA's about 15.5-15.8v

 

You can always do it again next week / next month if you find its not made much difference.

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WotEver Veteran II

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Posted
Posted
32 minutes ago, blackrose said:

So shall I wait until it reaches 16.2v, keep it stable at that voltage by reducing the amps and then give it an hour?

What you should do is...

 

  • Turn off the psu
  • Disconnect it
  • Set the psu voltage output to 16.2V as measured with a multimeter. 
  • LEAVE THE VOLTAGE CONTROL ALONE
  • Turn the current to full 
  • Connect the psu to the batteries 
  • Turn it on. 
     

Or... just continue as you are but ensure that the voltage doesn’t creep up. 

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blackrose Veteran II

blackrose

Posted
Posted (edited)
9 minutes ago, WotEver said:

What you should do is...

 

  • Turn off the psu
  • Disconnect it
  • Set the psu voltage output to 16.2V as measured with a multimeter. 
  • LEAVE THE VOLTAGE CONTROL ALONE
  • Turn the current to full 
  • Connect the psu to the batteries 
  • Turn it on. 
     

Or... just continue as you are but ensure that the voltage doesn’t creep up. 

 

Thanks. Yes I'm keeping a close eye on it. It's been at 16.17v for the last 20mins according to my Fluke multimeter. The PSU says 16.6v and my battery monitors say 16.2v and 16.1v. I think the Fluke is correct.

 

I'm going to give it another 10mins and then switch the PSU off. Should I switch my charger back on straight away or give the batteries a chance to rest?

3 minutes ago, blackrose said:

 

 

 

Edited by blackrose
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dmr Veteran II

dmr

Posted
Posted
2 minutes ago, blackrose said:

 

Thanks. Yes I'm keeping a close eye on it. It's been at 16.17v for the last 20mins according to my Fluke multimeter. The PSU says 16.6v and my battery monitors say 16.2v and 16.1v. I think the Fluke is correct.

You've just got a slightly weak connection somewhere or your wires are too thin so you have a little volt drop (0.4v) between the PSU and the batteries????

This is why alternator controllers measure the voltage actually at the batteries.

 

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

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Alan de Enfield Veteran II

Alan de Enfield

Posted
Posted
1 minute ago, blackrose said:

 

Thanks. Yes I'm keeping a close eye on it. It's been at 16.17v for the last 20mins according to my Fluke multimeter. The PSU says 16.6v and my battery monitors say 16.2v and 16.1v. I think the Fluke is correct.

Whatever the voltage, if its 'bubbling away' then it is doing what it is supposed to do.

 

Interestingly (Re Trojans) :

 

Equalizing wet cell batteries
1. The batteries must be fully charged to begin with.
 
2. Disconnect all loads. You are going to allow the battery voltage to rise higher than normal; to 15 or 16 volts for a 12 volt battery bank. You don't want to damage sensitive electronic equipment that might be connected.
 
3. Remove any hydrocaps fitted to the cells
 
4. Connect the charger and set it to the equalizing voltage.  (For Trojan wet cell batteries the recommended equalizing voltage is 15.5 volts for a 12 volt bank, for Rolls the equivalent voltage is 15.5 - 16 volts)
 
5. Batteries will begin gassing and bubbling vigorously
 
6. Don't allow the battery temperature to rise much above 115 degrees F and never above 125 degrees.  Measure from a center cell.
 
7. Take the specific gravity at hourly intervals
 
8. Equalization is complete when the specific gravity no longer rises.
 
For Rolls batteries the end of the instructions were more specific
 
9. If severely sulfated, it may take many hours for the specific gravity to rise.
    
10. Once the specific gravity begins to rise the bank voltage will most likely drop or the charging current will increase. The charging current may need to be lowered if temperature approaches 125ºF (46ºC). If the charge controller was by passed, it should now be used or put back in line.
    
11. Continue measuring the specific gravity until 1.265 is reached.
    
12. Charge for another 3 hours. Add water to maintain the electrolyte above the plates.
    
13. Allow bank to cool and check and record the specific gravity of each cell. The gravities should be 1.265 ± 0.005 or lower. Check the cell electrolyte levels and add water IF necessary.
 
 
 

From the Battery University :

An equalizing charge is nothing more than a deliberate overcharge to remove sulfate crystals that build up on the plates over time. ... An equalizing charge also reverses acid stratification, a condition where acid concentration is greater at the bottom of the battery than at the top.

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blackrose Veteran II

blackrose

Posted
Posted
1 minute ago, dmr said:

You've just got a slightly weak connection somewhere or your wires are too thin so you have a little volt drop (0.4v) between the PSU and the batteries????

 

Possibly. For convenience I've connected the PSU to one of my battery charger output cables. Cables are about 60mm2, but cable length is about 2m one way.

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blackrose Veteran II

blackrose

Posted
Posted (edited)
26 minutes ago, Alan de Enfield said:

Whatever the voltage, if its 'bubbling away' then it is doing what it is supposed to do.

 

Interestingly (Re Trojans) :

 

Equalizing wet cell batteries
1. The batteries must be fully charged to begin with.
 
2. Disconnect all loads. You are going to allow the battery voltage to rise higher than normal; to 15 or 16 volts for a 12 volt battery bank. You don't want to damage sensitive electronic equipment that might be connected.
 
3. Remove any hydrocaps fitted to the cells
 
4. Connect the charger and set it to the equalizing voltage.  (For Trojan wet cell batteries the recommended equalizing voltage is 15.5 volts for a 12 volt bank, for Rolls the equivalent voltage is 15.5 - 16 volts)
 
 

 

I'm getting 16.2v from the Trojan website (Table 2 in the charging section)

 

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

 

Also what are hydrocaps? Some sort of watering system? Or was I supposed to do the equalisation charge with the caps open?

 

Anyway, 'tis done. I haven't taken SG readings, but I'll just do the same thing a few times/year.

 

Fortunately it doesn't seem to have damaged any of my connected equipment. Chargers are working fine although I haven't checked my inverter yet. That's one good thing about Sterling equipment - it may not be the most sophisticated by it's pretty robust.

Edited by blackrose
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Alan de Enfield Veteran II

Alan de Enfield

Posted
Posted (edited)
17 minutes ago, blackrose said:

 

I'm getting 16.2v from the Trojan website (Table 2 in the charging section)

 

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

 

Also what are hydrocaps?

There seems to be very little consistency in battery information when you look across different sources. But it is probably fair to suggest the manufacturer knows what is 'best' for their product.

 

I'm only guessing, but I would assume Hydrocaps are the screw caps on the top of each cell (the filler caps)

 

Close :

 

http://support.rollsbattery.com/support/solutions/articles/19469-hydrocaps

Edited by Alan de Enfield
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dmr Veteran II

dmr

Posted
Posted
58 minutes ago, blackrose said:

 

I'm getting 16.2v from the Trojan website (Table 2 in the charging section)

 

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

 

 

 

If you search the www for various Trojan documents you will find a few inconsistencies regarding equalsation voltage (and other matters) so even Trojan are not exactly sure about this. Try 15.5v and if that does not work then increase it to about 16.

 

Maybe 15.5 is stated because its less stress on connected devices, but 16 is better if you are careful and brave????

 

16v from the Engineering department, 15.5 v from the customer services/marketing dept?   :)

 

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

 

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

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