Equalising Trojan Lead Flooded Batteries

[towpathrider]

Just thought i'd post this as it came as a bit of a surprise to me, I've been maintaining my t-105's based on the data sheet here, but also have come accross the trojan batteries user guide which specifies different values for Equalise voltage (16.2v) and absoroption (14.1 - 14.7)

 

I've contacted Trojan in the UK and US and they both recommended going by the user guide, NOT the data sheet. I asked for clarification on the charging values for the T-105's and the reply was:

 

Use 16.2V for the EQ voltage setting. Your absorption voltage of 14.8 is correct. The Float setting can be 13.2V up to 13.5V

 

So there you go! - not that you can't equalise at 15.5, but it takes much, much longer. (in my experience)

 

Next problem is getting my Victron Phoenix to charge at 16.2. I can get it up to 16v in absorption using the VEConfigure II Software (that's the max value), forced equalisation seems to top out at 15.5v. Be interested to hear anyone else's experience here.

 

 

[nicknorman]

Just thought i'd post this as it came as a bit of a surprise to me, I've been maintaining my t-105's based on the data sheet here, but also have come accross the trojan batteries user guide which specifies different values for Equalise voltage (16.2v) and absoroption (14.1 - 14.7)

 

I've contacted Trojan in the UK and US and they both recommended going by the user guide, NOT the data sheet. I asked for clarification on the charging values for the T-105's and the reply was:

 

Use 16.2V for the EQ voltage setting. Your absorption voltage of 14.8 is correct. The Float setting can be 13.2V up to 13.5V

 

So there you go! - not that you can't equalise at 15.5, but it takes much, much longer. (in my experience)

 

Next problem is getting my Victron Phoenix to charge at 16.2. I can get it up to 16v in absorption using the VEConfigure II Software (that's the max value), forced equalisation seems to top out at 15.5v. Be interested to hear anyone else's experience here.

 

Yes I'd noticed the 16.2 as well, and of course that is the 25C value, it will be more with cold batteries. My mastervolt charger only goes up to 16v. Anyway I think the point is that as you say, EQ can be successfully done at lower voltages, it just takes longer.

[blackrose]

My Sterling charger only goes up to 14.8v so I am screwed!

 

I think I asked this question about my new Trojans before and the consensus was that it didn't matter that much. My previous set of wet lead/acid domestic batteries lasted 10 years, so the equalisation charge can't be that important.

[nicknorman]

My Sterling charger only goes up to 14.8v so I am screwed!

 

I think I asked this question about my new Trojans before and the consensus was that it didn't matter that much. My previous set of wet lead/acid domestic batteries lasted 10 years, so the equalisation charge can't be that important.

Do you have solar? Maybe the controller's output voltage can be wound up?

 

Ours are 2 years old and I have EQd them once since new. On the other hand they get fully charged by being on shore power float, or long days cruising. If we were mostly static off grid and charging from a genny (which tends to lead to charging only just enough) it might have been a different matter.

[Graham.m]

My Sterling charger only goes up to 14.8v so I am screwed!

 

I think I asked this question about my new Trojans before and the consensus was that it didn't matter that much. My previous set of wet lead/acid domestic batteries lasted 10 years, so the equalisation charge can't be that important.

 

The Sterling Pros equalise at 15.5V with a max charge rate of 15.1V just for those with Sterling Pros

 

At a lower voltage it just takes longer

[Nickhlx]

I would add that some devices on the load may be unhappy about being presented with 16+ volts on their supply lines, and it might be prudent to isolate them whilst doing an equalisation charge.

 

Nick

[Phil.]

I use my solar charger to do this normally based on these figures

http://www.trojanbattery.com/BatteryMaintenance/Charging.aspx

 

I can up the voltage further than the current 15.5 volts, is the 16+ volts newer info and should I do it.

[WotEver]

My Sterling charger only goes up to 14.8v so I am screwed!

 

I think I asked this question about my new Trojans before and the consensus was that it didn't matter that much. My previous set of wet lead/acid domestic batteries lasted 10 years, so the equalisation charge can't be that important.

You obviously have a very good charging regime ?

 

It's doubtful that they'd need equalising very often if at all with that kind of care.

[towpathrider]

Yeah, for those of us off grid and needing to equalise in the winter the 16.2 is useful because it's quicker. Running a generator for hours at 10a/h seems like such a waste so the shorter the better. For those of you on shore power, or using solar in the summer it's not such a big deal.

 

 

In terms of when to equalise:

 

"Trojan recommends equalizing every 30 days or when batteries have a low specific gravity reading after fully charging, below 1.235, or have a wide ranging specific gravity of >0.030 points between cells"

 

is the 16+ volts newer info and should I do it.

 

I contacted them this week.

 

Interestingly does anyone know why certain cells end up being less charged than others? manufacturing tolerances? unequal distribution of charge/discharge? uneven levels of electrolyte?

Edited January 21, 2016 by towpathrider

[cuthound]

Equalisation is required when some cells are less charged than others, the clue is in the name.

 

How unevenly the cells are charged depends on the type of use they are put to.

 

Cells which are regularly discharged but not fully charged need it the most frequently, followed by cells not discharged mmuch but held on float voltages of 2.2 volts per cell or less (often because of stratification, where layers of electrolyte are at different sg's.

 

Cells held on float voltages over 2.25 volts per cell generally don't require equalising periodically.

[cuthound]

 

Interestingly does anyone know why certain cells end up being less charged than others? manufacturing tolerances? unequal distribution of charge/discharge? uneven levels of electrolyte?

 

It is usually because the cells have slightly different internal resistances, and thus take different charge currents. Sometimes it is because some cells have a higher self discharge current than others.

 

I have seen some battery installations where each 2 volt cell has a transistorised shunt circuit across it, so that when that cell is charged, the charging current is bypassed to the next cell to avoid overcharging that cell and shortening its life. However this is only worth doing on large, expensive commercial installations.

[Nickhlx]

"It is usually because the cells have slightly different internal resistances, and thus take different charge currents."

 

How can different cells in the same battery be exposed to different charge and discharge currents ? As they are in SERIES, the same current must flow through each cell...

Edited January 21, 2016 by Nickhlx

[cuthound]

"It is usually because the cells have slightly different internal resistances, and thus take different charge currents."

 

How can different cells in the same battery be exposed to different charge and discharge currents ? As they are in SERIES, the same current must flow through each cell...

I obviously didn't make myself clear. As I am sure you know batteries are composed of interlaced positive and negative plates, paralleled to increase capacity. There are often short circuits within batteries, caused by the active material falling from the plates and shorting them out, or by the active material falling to the bottom of the cell and causing a short there. The shorts are parallel paths, hence the changes in internal resistance Doh!

[WotEver]

"It is usually because the cells have slightly different internal resistances, and thus take different charge currents."

 

How can different cells in the same battery be exposed to different charge and discharge currents ? As they are in SERIES, the same current must flow through each cell...

That is of course correct. The individual cells will have slightly different voltages across them, resulting in slightly different SoC amounts.

 

Tony

[Nickhlx]

Just testing (!)

[Graham.m]

I obviously didn't make myself clear. As I am sure you know batteries are composed of interlaced positive and negative plates, paralleled to increase capacity. There are often short circuits within batteries, caused by the active material falling from the plates and shorting them out, or by the active material falling to the bottom of the cell and causing a short there. The shorts are parallel paths, hence the changes in internal resistance Doh!

 

Or even the slight differences in the plates during manufacture

[smileypete]

I don't think there is any easy, cheap, off-the-shelf way of generating equalisation voltages.

 

Some more budget options involve bench power supplies, unregulated solar panels, or dc boost converters. The best budget option may depend on what electrical skills you have, and whether you need to run loads while equalisation takes place.

 

Normally equalisation charging takes place at up to C/30 so it doesn't need a huge power source.

 

cheers, Pete.

smpt

Edited January 21, 2016 by smileypete

[Jambo]

Anyone got any ideas as to how many hours to equalise for at the different voltages? I think I was doing 4 or 5 hours at 15.5V from memory but I'd have to check my outback settings. I can't wait for the first decent sunshine in February or March to give them a good long EQ tickle. Sadly our Mastervolt won't stay in EQ mode for some reason so we're reliant on the Outback.

[nicknorman]

Anyone got any ideas as to how many hours to equalise for at the different voltages? I think I was doing 4 or 5 hours at 15.5V from memory but I'd have to check my outback settings. I can't wait for the first decent sunshine in February or March to give them a good long EQ tickle. Sadly our Mastervolt won't stay in EQ mode for some reason so we're reliant on the Outback.

It depends on how much equalisation is needed. What are the fully charge specific gravities (adjusted for temperature)? Unless they are bad I would have thought an hour or two would be sufficient for maintenance EQ. Regarding the mastervolt, we find it won't stay in EQ for more than about 30 mins. However I just turn up the set voltage to 15.5v using the interface (PC etc). What mastervolt device do you have?

[Graham.m]

Anyone got any ideas as to how many hours to equalise for at the different voltages? I think I was doing 4 or 5 hours at 15.5V from memory but I'd have to check my outback settings. I can't wait for the first decent sunshine in February or March to give them a good long EQ tickle. Sadly our Mastervolt won't stay in EQ mode for some reason so we're reliant on the Outback.

 

Habari

 

Do they need more that the Mastervolt is giving them. As you are equalising you will have flood batteries, so I suggest get a hydrometer and measure the SG at the start of equalisation and check it every 1/2 hour when it stops rising the battery is equalised. It does not always need hours of equalisation sometime an hour is enough

Edited January 21, 2016 by Graham.m

[Phil.]

Anyone got any ideas as to how many hours to equalise for at the different voltages? I think I was doing 4 or 5 hours at 15.5V from memory but I'd have to check my outback settings. I can't wait for the first decent sunshine in February or March to give them a good long EQ tickle. Sadly our Mastervolt won't stay in EQ mode for some reason so we're reliant on the Outback.

I use my outback to EQ usually every couple of months and have it currently set for two hours at 15.5 volts. Reading this thread I am wondering if I should ramp up the voltage a bit. I find the outback far better than using the mastervolt at doing an EQ charge.

[blackrose]

Do you have solar? Maybe the controller's output voltage can be wound up?

 

Not yet, it's next on the list.

[Jambo]

It depends on how much equalisation is needed. What are the fully charge specific gravities (adjusted for temperature)? Unless they are bad I would have thought an hour or two would be sufficient for maintenance EQ. Regarding the mastervolt, we find it won't stay in EQ for more than about 30 mins. However I just turn up the set voltage to 15.5v using the interface (PC etc). What mastervolt device do you have?

 

I'm not sure we've even got 30 minutes out of it but it was a while ago I tried. Interesting point about hooking it up to the laptop. I'd been meaning to do that for a while to tweak the settings so that they're a better match to my batteries than the dip switches can manage. We've got a Mass Combi 12/2000.

[peterboat]

my midnite solar does equalisation every 28 days or if i feel adventurous when i press the button on a sunny day

[jenevers]

Does anyone know if the Tracer MPPT 40A charge controllers have an equalising function?

If so, is it automatic or does it need programming or setting up/starting manually?

 

Oops! Just downloaded manual and page 10 says it automatically does a 120 minute equalisation if the charger detects the battery being over discharged.

( only 14.8v for flooded 12v batteries though. But manual implies this can be user adjusted between 9 - 17v!)

 

http://www.pvsolarchina.com/wp-content/uploads/2014/07/TRACER-BN-manual.pdf

Edited January 25, 2016 by jenevers