Equalisation charge - is it a waste of time?

[Alan de Enfield]

5 minutes ago, Richard10002 said:

The picture of Alans', (de Enfield), power supply, only seems to go up to 3.5A, and it's in the red from 3.0A. So I'd guess that your 5A will be fine.

The equalisation charge is all about 'volts' I just run it a 3-3.5a and 15.5 volts with a quick burst up around 16v to start the 'fizzing'.

[blackrose]

12 minutes ago, Alan de Enfield said:

The equalisation charge is all about 'volts' I just run it a 3-3.5a and 15.5 volts with a quick burst up around 16v to start the 'fizzing'.

 

So what's dmr on about when he says I'm being optimistic using 3.5v?

[dmr]

22 minutes ago, blackrose said:

 

3 x 150 amp hour. What sort of problems? It's when they get older that I will need equalisation/desulphation.

 

If the tail current of the batteries is 10amps will the 5amp bench power supply just not work? 

 

Should I have bought a bigger max output bench power supply?

Yes, it just won't work. If the tail current is more than the PSU can deliver then the PSU will not be able to take over the charge, let alone raise the voltage to equalisation level. You might be able to split the bank and equalise each battery on its own but that's a bit tedious. A 20 amp PSU would be better but they start to get both big and expensive at higher currents.

 

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

[blackrose]

4 minutes ago, dmr said:

Yes, it just won't work. If the tail current is more than the PSU can deliver then the PSU will not be able to take over the charge, let alone raise the voltage to equalisation level. You might be able to split the bank and equalise each battery on its own but that's a bit tedious. A 20 amp PSU would be better but they start to get both big and expensive at higher currents.

 

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

 

Ah ok. I guess I should have bought a higher output unit. 10amp was only a few quid more. But then how's Alan doing it?

 

Edit: is it possible to do an equalisation charge from a bench power supply with a battery charger on float simultaneously, just so the tail current is low?

Edited July 31, 2019 by blackrose

[Alan de Enfield]

Just now, blackrose said:

 

So what's dmr on about when he says I'm being optimistic using 3.5v?

As you will be doing I start with batteries 99.99% (ish) charged at up to 14.7v by the solar / battery charger.

 

I don't seem to have any problem getting the voltage up to 15.5 on my bank of 2 x 200 Ah batteries. (just under 1% )

 

I have 2 banks of leisure batteries (2 x 200Ah) , one 'bank' + 1x 200Ah starter battery on each engine.

[nicknorman]

3 hours ago, blackrose said:

Why isn't it connected by the manufacturer if it's important?

Because that ties the negative to earth/ground, something you might not want (ie you might want a floating output.) when powering some bit of an electronic thingy.

[dmr]

1 hour ago, blackrose said:

 

Ah ok. I guess I should have bought a higher output unit. 10amp was only a few quid more. But then how's Alan doing it?

 

Edit: is it possible to do an equalisation charge from a bench power supply with a battery charger on float simultaneously, just so the tail current is low?

No, it does not usually work like that, the device supplying the higher voltage will take on all of the workload whilst the lower voltage device will just get confused and shut down, though if you are very very unluckily it will drop dead.

 

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

[Richard10002]

18 minutes ago, dmr said:

No, it does not usually work like that, the device supplying the higher voltage will take on all of the workload whilst the lower voltage device will just get confused and shut down, though if you are very very unluckily it will drop dead.

 

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

You've lost me now  

 

Surely, when you are charging with the bench supply, you would turn off all other charging sources?

 

Having said that, surely the Bench supply will have the higher voltage, because you are setting it to have the higher voltage?

[dmr]

11 minutes ago, Richard10002 said:

You've lost me now  

 

Surely, when you are charging with the bench supply, you would turn off all other charging sources?

 

Having said that, surely the Bench supply will have the higher voltage, because you are setting it to have the higher voltage?

I routinely charge from two alternators and a battery charger and they work as a team and add their currents together, but as the voltage increases they drop out till just the one set to the highest voltage is working.

So, the PSU doing the equalisation charge will be the highest voltage device and so will get no help from any other chargers.

 

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

[blackrose]

On 31/07/2019 at 23:28, dmr said:

I routinely charge from two alternators and a battery charger and they work as a team and add their currents together, but as the voltage increases they drop out till just the one set to the highest voltage is working.

So, the PSU doing the equalisation charge will be the highest voltage device and so will get no help from any other chargers.

 

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

 

But if you gradually dialed up the voltage of the PSU wouldn't  another charger only drop out at the point at which the PSU exceeded its voltage? Meaning you could have a charger on simultaneously to get the batteries so that they were on float accepting less than 1 amp at say 13.6v and then dial up the voltage of the PSU from say 12.8v to 15.5v. Wouldn't that work?

Edited August 1, 2019 by blackrose

[WotEver]

8 hours ago, blackrose said:

 

But if you gradually dialed up the voltage of the PSU wouldn't  another charger only drop out at the point at which the PSU exceeded its voltage? Meaning you could have a charger on simultaneously to get the batteries so that they were on float accepting less than 1 amp at say 13.6v and then dial up the voltage of the PSU from say 12.8v to 15.5v. Wouldn't that work?

Sure, that would work. 

 

All an equalisation/desulphating charge is is a controlled over charge. So you charge your batteries until they’re at 99.9% SoC and then you apply the overcharge voltage for a period. The high voltage causes the electrolyte to bubble away, reducing stratification, pushing all cells towards 100%, and helping to dissolve hardened sulphate. 

[Alan de Enfield]

6 minutes ago, WotEver said:

Sure, that would work. 

 

All an equalisation/desulphating charge is is a controlled over charge. So you charge your batteries until they’re at 99.9% SoC and then you apply the overcharge voltage for a period. The high voltage causes the electrolyte to bubble away, reducing stratification, pushing all cells towards 100%, and helping to dissolve hardened sulphate. 

Which is exactly what I do (see post #80)

 

Despite some saying that the current needs to be higher, I have never found a problem with my 3 amps.

The 'volts do the work'.

[dmr]

9 hours ago, blackrose said:

 

But if you gradually dialed up the voltage of the PSU wouldn't  another charger only drop out at the point at which the PSU exceeded its voltage? Meaning you could have a charger on simultaneously to get the batteries so that they were on float accepting less than 1 amp at say 13.6v and then dial up the voltage of the PSU from say 12.8v to 15.5v. Wouldn't that work?

 

The charger and PSU would most likely work togerher, though not 100% certain, I have blown up a PSU doing something similar. But as you say, once the PSU voltage exceeds the charger voltage the charger will drop out leaving the PSU to do all the work. 3.5amp is quite low and when the batteries are a little older this might not be enough. I also suspect that sulphated batteries have a higher tail current but am not certain. My experience is 100% off grid liveaboard (*) so your batteries may well show a lower tail current because they have a much nicer life.

 

* And as we have now returned to the K&A I have decided to call myself a "liveaboard boater", or possibly just a full time boater, to distinguish us from the liveaboards that are not really boaters .  or maybe just a "non blue tarpaulin boater".

 

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

[Alan de Enfield]

2 minutes ago, dmr said:

* And as we have now returned to the K&A I have decided to call myself a "liveaboard boater", or possibly just a full time boater, to distinguish us from the liveaboards that are not really boaters .  or maybe just a "non blue tarpaulin boater".

That's a good plan.

 

 

Greeny :

 

 

[MtB]

 

I've always aspired to one of them blue tarpaulins....

 

 

 

[WotEver]

23 minutes ago, Mike the Boilerman said:

 

I've always aspired to one of them blue tarpaulins....

Alas I only have green. But I do have two, so I guess that counts for something...

[dmr]

You can get proper tarpaulins on eBay for a little bit more money, no excuse for the nasty blue plastic stuff, but I fear for some liveaboards its all part of the liveaboard image. Very sad yesterday to see what used to be quite a good boat intentionally degraded to a liveaboard tip.

 

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

[MtB]

4 minutes ago, dmr said:

You can get proper tarpaulins on eBay for a little bit more money, no excuse for the nasty blue plastic stuff, but I fear for some liveaboards its all part of the liveaboard image. Very sad yesterday to see what used to be quite a good boat intentionally degraded to a liveaboard tip.

 

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

 

Not a new phenomenon either. I met a boater on the K&A about 15 years ago in a Rodney boat with a fully grown buddleia perhaps 8ft high growing out of his stern fender. He was very proud of it and tended it with loving care. He was very much into the 'scruffy boat chic' thing. 

[blackrose]

Tried to do an equalisation charge today but I can't seem to get the bench power supply to work.

 

My regular charger was putting out 1amp/14.8v so I assume that's the tail current. I connected the bench power supply to the charger output cables but I'm not able to input any current or volts from the bench power supply?

 

I have 2 chargers but the one I've connected the bench power supply to supplies the domestic bank only.  

 

 

[WotEver]

34 minutes ago, blackrose said:

Tried to do an equalisation charge today but I can't seem to get the bench power supply to work.

Have you tested it with its output disconnected?  Perhaps it’s faulty. 

[blackrose]

43 minutes ago, WotEver said:

Have you tested it with its output disconnected?  Perhaps it’s faulty. 

 

No, how would I test it? Just put a multimeter and clamp meter on the output?

 

Doesn't it need to be connected to something to work?

Edited December 21, 2019 by blackrose

[WotEver]

16 minutes ago, blackrose said:

 

No, how would I test it? Just put a multimeter and clamp meter on the output?

 

Doesn't it need to be connected to something to work?

1. Just a multimeter. No circuit so no current so nothing for a clamp meter to read. 
 

2. Nope

[blackrose]

The voltage output seems to be fine according to my multimeter.

[WotEver]

49 minutes ago, blackrose said:

The voltage output seems to be fine according to my multimeter.

Then it may be shutting down... if you connect it back up to the batteries does the PSU voltage remain the same, or does it drop to battery voltage. 

[blackrose]

39 minutes ago, WotEver said:

Then it may be shutting down... if you connect it back up to the batteries does the PSU voltage remain the same, or does it drop to battery voltage. 

It just shows what the battery charger is putting out, as in my photo. I tried to turn up the voltage (and the current) but nothing happened. 

Edited December 21, 2019 by blackrose