Charging regime while on shore power

[alanch]

Count me as one to keep the charger on. In 11 years I have always kept the charger on. Haven't replaced a battery for 7 years, and I do not monitor usage. Just switch it on and go. No worries - touch wood!

 

[KellysEye]

We had a 25 AMP 240 volt AC Xantrex smart battery charger which automatically brings batteries up to charge and then switches off. We had both lead acid and gel batteries which have different charging regimes you can set the Xantrex to each battery type. It's a brilliant piece of kit.

 

[Norman_E]

It's not crystal clear what's best in this situation.
I certainly agree with switching the charger off when the batteries are fully charged and are totally isolated and the boat is being left.
However in your case the batteries are not isolated and are discharging - I don't know by how much in a week.
The charger's switching to float does not mean that the batteries are fully charged; it just means it has reached a state where further charging at the higher voltage will produce gas and heat but only a slow increase in state of charge, hardly any quicker than at a lower voltage (with a floor of 13.8V below which you will maintain state of charge, offsetting self discharge, but won't go to full charge.) I don't know the switching criteria that this particular charger uses, but commonly it equates to 80-90% SoC.
Reaching really full charge at 13.8V takes many hours.
So you are actually ensuring that your batteries are never fully charged.
What battery capacity do you have and how much does the a/f take?

315AH house batteries and 105AH engine battery. All fully charged after three days on shore power before I left. The A/F is low powered. I don't know how much it draws but the ammeter barely shows any consumption when everything else is turned off. On turning on the charger it will firstly show 30 amps being delivered on boost charge at 14.4 volts, but the amperage rapidly drops because the batteries are charged and the charger switches to its second phase of charging at 13.4 volts with the amps supplied continuing to decline as the batteries become "full", then it will drop down to float mode at about one amp. All this will happen well within the time that the charger is switched on by the timer, which is actually just over 5 hours as I use a mechanical timer with 14 on/off segments per day, and have three segments pressed in. (24/14x3=5.1429)

 

[lw395]

......
Do you have any references for your first suggestion about frequent shallow discharges? It's certainly not an idea that had any acceptance in the years I was in the battery manufacturing industry, but ideas can change.

I have seen a few references suggesting that either frequent shallow cycling or a bit of AC on the float voltage are good things.
google is not finding them for me today though!
Here is one article:
http://canadus.com/battery-basics-sulfation/
""There are many causes of sulfation, including acid stratification, excessive battery discharge, chronic undercharging, infrequent use, and leaving batteries (even new batteries) in a discharged state for extended periods of time. Subjecting batteries to extended periods of float charging also creates ‘dendritic’ sulfation.

Over time, and without exception, sulfation will reduce the performance and life of every lead-acid battery.""

I've heard others say some batteries are subject to being 'killed by kindness', ie being put on a float charger all winter for a motorbike battery.
Being a bit careful with the cash, I only have one float charger and move it around various batteries. My main bike battery is now in either its fourth or fifth summer, when many people expect to buy a new one yearly. It's a big bike and a little battery.
But it is a Yuasa.

Do you have any views on Desulfators, or even De-sulphators?

 

[Sailingsaves]

I have seen a few references suggesting that either frequent shallow cycling or a bit of AC on the float voltage are good things.
google is not finding them for me today though!
Here is one article:
http://canadus.com/battery-basics-sulfation/
""There are many causes of sulfation, including acid stratification, excessive battery discharge, chronic undercharging, infrequent use, and leaving batteries (even new batteries) in a discharged state for extended periods of time. Subjecting batteries to extended periods of float charging also creates ‘dendritic’ sulfation.

Over time, and without exception, sulfation will reduce the performance and life of every lead-acid battery.""

I've heard others say some batteries are subject to being 'killed by kindness', ie being put on a float charger all winter for a motorbike battery.
Being a bit careful with the cash, I only have one float charger and move it around various batteries. My main bike battery is now in either its fourth or fifth summer, when many people expect to buy a new one yearly. It's a big bike and a little battery.
But it is a Yuasa.

Do you have any views on Desulfators, or even De-sulphators?

I think you have it spot on as usual.

12V batteries like to be fully charged and only discharged a little (as in down to 12.6V) before being re-charged.

When fully charged, and on float, a tiny tiny discharge, keeps them happy as long as it is followed by a re-charge.

So moving your charger around when your batteries are on float is best practice (unless using a smart charger such as CTEK that does it all for you: keeps at float, then allows a tiny discharge before applying float charge again).

My experience is that so called de-sulphators are worthless (as in they do not work).

Don't allow sulphation to occur is the answer. If it does, pulse charging does not seem to be as good (in my experience and from what I have read) as other manual techniques such as charging a sulphated battery in paralled with a good one VERY slowly (tiny amps) , then discharging a little but at high amps (20 amps) to expand and contract the plates and crack the sulphation so normal chemistry can resume and the sulphate is attacked and turned back into decent chemicals.

It worked with an Optima battery that a mate allowed to drop to 0 Volts and left like that for months and junked. The same Optima now works really well and a drop tester shows it as almost 1000 CCA. And for the first time ever I own a £180 battery.

 

[Plevier]

I have seen a few references suggesting that either frequent shallow cycling or a bit of AC on the float voltage are good things.
google is not finding them for me today though!
Here is one article:
http://canadus.com/battery-basics-sulfation/
""There are many causes of sulfation, including acid stratification, excessive battery discharge, chronic undercharging, infrequent use, and leaving batteries (even new batteries) in a discharged state for extended periods of time. Subjecting batteries to extended periods of float charging also creates ‘dendritic’ sulfation.

Over time, and without exception, sulfation will reduce the performance and life of every lead-acid battery.""

I've heard others say some batteries are subject to being 'killed by kindness', ie being put on a float charger all winter for a motorbike battery.
Being a bit careful with the cash, I only have one float charger and move it around various batteries. My main bike battery is now in either its fourth or fifth summer, when many people expect to buy a new one yearly. It's a big bike and a little battery.
But it is a Yuasa.

Do you have any views on Desulfators, or even De-sulphators?

1 I would strongly disagree that a bit of AC on the float voltage is good. Any ripple on it promotes grid corrosion is the generally accepted view.
2 The best way of avoiding sulphation is to keep the battery fully charged.
3 I've never heard of dendritic sulphation. Dendritic growths piercing the separators and causing internal shorts used to happen in the days of high antimony content (8-10% used to be common.) They are not a problem with typical low antimony (usually 1.5%) or lead calcium as far as I know.
4 No I don't believe in desulphators - or in a lot of stuff on the websites of people who make them such as the one you quote!
5 Being on float charge all winter at the correct voltage and without ripple on it should not do any harm but is not necessary if the battery is completely isolated and clean and dry externally, left fully charged, and given a boost charge when recommissioned. Any modern battery in good condition should be happy like that for at least 3 months, usually 6.
6 Yuasa batteries are good but not special. An Exide for example should be just as good. There are plenty of rubbish ones around too of course.

 

[Plevier]

When fully charged, and on float, a tiny tiny discharge, keeps them happy as long as it is followed by a re-charge.
## but no discharge will keep them even happier!

My experience is that so called de-sulphators are worthless (as in they do not work).
## we'll agree on that

charging a sulphated battery in paralled with a good one VERY slowly (tiny amps) , then discharging a little but at high amps (20 amps) to expand and contract the plates and crack the sulphation so normal chemistry can resume and the sulphate is attacked and turned back into decent chemicals.
## there are many "folk remedies" but that's one I've not heard; what do you believe the parallel good battery achieves, and what do you think the effect is on the good one? How do you achieve the tiny amps - constant voltage charge or constant current? - and what do you call tiny? Expanding and contracting the plates is what happens in every discharge cycle and is why cycling shortens the life. it cracks the active material away from the grid. Sulphation generally forms on the surface and in the mass of the plate AFAIK, not at the paste:grid interface. So I'm rather dubious about this technique (but haven't anything better to offer).

It worked with an Optima battery that a mate allowed to drop to 0 Volts and left like that for months and junked. The same Optima now works really well and a drop tester shows it as almost 1000 CCA. And for the first time ever I own a £180 battery.
## Optima batteries do seem to be remarkably tolerant (like the original Gates Cyclons where this technology was developed but is now out of patent) but boy the price!!.

..

 

[lw395]

....
6 Yuasa batteries are good but not special. An Exide for example should be just as good. There are plenty of rubbish ones around too of course.

For the size that fits my bike, the Yuasa has a significantly higher CCA rating, compared to the Exide. I don't think that's such an issue for most boats though!
I've played around with desulfators a little, seen batteries recover from 'useless' to 'useful for non-demanding applications', which kind of tallies with some people who use scrap batteries in-off-grid solar.
But my bikes and boats get new batteries when they need them. There's no point saving £20 by getting another year out of a battery and ruining a £100 starter motor for instance.
YMMV as they say.

 

[Bongo]

Yeh..but..as a recent haul out revealed a nearly all gone pear anode, in one year, I'm re-thinking leaving shore power on..

..so how do I find my electrolysis problem.(A.W.B.) ?

 

[Plevier]

For the size that fits my bike, the Yuasa has a significantly higher CCA rating, compared to the Exide.

Well that's a double edged sword. It almost certainly means the Yuasa has more but thinner plates which is better for CCA but not as good for corrosion life (or cycle life but that probably isn't relevant here.)
If you really need all the starting amps you can get, then the Yuasa is the better battery for you.
If you have more CCA than you need, then the lower rated Exide might last longer.
I used to use an Exide motorcycle battery - 24Ah nominal I think, a big BMW fitment - to start a 100HP 3.3L Continental engine in a plane, it coped with that!

 

[Plevier]

315AH house batteries and 105AH engine battery. All fully charged after three days on shore power before I left. The A/F is low powered. I don't know how much it draws but the ammeter barely shows any consumption when everything else is turned off. On turning on the charger it will firstly show 30 amps being delivered on boost charge at 14.4 volts, but the amperage rapidly drops because the batteries are charged and the charger switches to its second phase of charging at 13.4 volts with the amps supplied continuing to decline as the batteries become "full", then it will drop down to float mode at about one amp. All this will happen well within the time that the charger is switched on by the timer, which is actually just over 5 hours as I use a mechanical timer with 14 on/off segments per day, and have three segments pressed in. (24/14x3=5.1429)

Did you build the Jaycar a/f kit? I think I recall some posts about it. Their spec says 220mA average consumption. That's 37Ah a week. 12% of your house bank capacity. Not insignificant.
Sterling kit always seems to get Marmite reactions and you obviously do like it so I don't think I should pursue this!

Have you considered putting in a mains PSU just for the A/F so you could leave batteries fully isolated? You could also run it isolated from boat metalwork so no galvanic corrosion worries if you don't already have a GI. By chance I have several spare mains plug style 12V PSUs that would probably do the job, you are welcome to one for the cost of postage if any interest.

 

[lw395]

Well that's a double edged sword. It almost certainly means the Yuasa has more but thinner plates which is better for CCA but not as good for corrosion life (or cycle life but that probably isn't relevant here.)
If you really need all the starting amps you can get, then the Yuasa is the better battery for you.
If you have more CCA than you need, then the lower rated Exide might last longer.
I used to use an Exide motorcycle battery - 24Ah nominal I think, a big BMW fitment - to start a 100HP 3.3L Continental engine in a plane, it coped with that!

The bike is only 1 litre, but 118bhp, being started by 14Ah IIRC. That's 500cc of big bore piston at 11 to 1 or something.
My old bike, a Guzzi, took a car battery intended for a BL mini.

 

[Norman_E]

Plevier, Yes they are Jaycar kits (two of them) The thread with the most views on the PBO forum is this one, which I started. http://www.ybw.com/forums/showthread.php?258391-Building-the-Ultrasonic-Antifouling-Kit-from-Jaycar I did consider using a mains PSU and have one that might do the job, from an old jump starter, but I would need to remember to switch them from mains to battery and back again. I did note that the last time I left the batteries off charge for 3 days whilst sailing, including one night with the anchor light on, plus internal LED lighting use and water pump use, with only a short amount of engine run time the battery charger settled into float mode within an hour of connection. You may be correct on Jaycar consumption but even if the house batteries are 25% discharged before recharging I reckon they will not come to any harm and I would rather do that than leave them on constant float charge, though I have noticed that the Sterling charger switches itself completely off from time to time. I really must re-read its manual.

The reason I don't like leaving a charger permanently on, is that the only boat fire in the marina in recent years was caused by a charger.

 

[Norman_E]

The bike is only 1 litre, but 118bhp, being started by 14Ah IIRC. That's 500cc of big bore piston at 11 to 1 or something.
My old bike, a Guzzi, took a car battery intended for a BL mini.

Real motorbikes had a kick starter! You had to learn the correct procedure to get a Velocette Venom going.

 

[ghostlymoron]

Best starter batteries don't have a quoted ahr rating, just CCA and vice versa. Those with both are dual purpose leisure types but probable quite adequate. Battery threads get unfeasibly long and convoluted.

315AH house batteries and 105AH engine battery. All fully charged after three days on shore power before I left. The A/F is low powered. I don't know how much it draws but the ammeter barely shows any consumption when everything else is turned off. On turning on the charger it will firstly show 30 amps being delivered on boost charge at 14.4 volts, but the amperage rapidly drops because the batteries are charged and the charger switches to its second phase of charging at 13.4 volts with the amps supplied continuing to decline as the batteries become "full", then it will drop down to float mode at about one amp. All this will happen well within the time that the charger is switched on by the timer, which is actually just over 5 hours as I use a mechanical timer with 14 on/off segments per day, and have three segments pressed in. (24/14x3=5.1429)

 

[lpdsn]

... continuing to decline as the batteries become "full", then it will drop down to float mode at about one amp.

One Amp is a pretty high current for a charge that has switched into float mode and is trickle charging your batteries. The old kaput batteries that came with the boat used to take that much on trickle charge, but they really were kaput. The new batteries, now 6 years old, take <0.1A. That's the current into two in parallel.

 

[Plevier]

One Amp is a pretty high current for a charge that has switched into float mode and is trickle charging your batteries. The old kaput batteries that came with the boat used to take that much on trickle charge, but they really were kaput. The new batteries, now 6 years old, take <0.1A. That's the current into two in parallel.

Yes it is high. I nearly said something about it too. It indicates that the batteries are some way from fully charged.

 

[Plevier]

Plevier, Yes they are Jaycar kits (two of them) The thread with the most views on the PBO forum is this one, which I started. http://www.ybw.com/forums/showthread.php?258391-Building-the-Ultrasonic-Antifouling-Kit-from-Jaycar I did consider using a mains PSU and have one that might do the job, from an old jump starter, but I would need to remember to switch them from mains to battery and back again. I did note that the last time I left the batteries off charge for 3 days whilst sailing, including one night with the anchor light on, plus internal LED lighting use and water pump use, with only a short amount of engine run time the battery charger settled into float mode within an hour of connection. You may be correct on Jaycar consumption but even if the house batteries are 25% discharged before recharging I reckon they will not come to any harm and I would rather do that than leave them on constant float charge, though I have noticed that the Sterling charger switches itself completely off from time to time. I really must re-read its manual.

The reason I don't like leaving a charger permanently on, is that the only boat fire in the marina in recent years was caused by a charger.

I hesitate to say any more - feel free to say MYOB!
I would not like to cycle a battery 25% weekly. That is enough to shorten its life (for most batteries in most circumstances). It also increases the sulphation risk especially in high ambients. I also doubt very much that you are getting full recharge with your weekly cycle as it stands.
I don't like leaving chargers on permanently either. However personally I would be looking at having a charge period twice a week or every other day. I don't think the Sterling charger adapts very well to this routine though if I have the correct information on it. I would not want a timed 14.4V charge on a battery starting at a high state of charge, I would just want a few hours at 13.8-14V but I don't think you can set the Sterling for that (as far as I can see in the manual I found).

 

[ex-Gladys]

Yes can still do a quick check on what my appliances are using in just a few minutes with charger off.

If you are concerned about this (depending on how your charger is connected to the batteries - i.e. mine bolts to the battery posts, and so charging current doesn't travel through the supply cables ) think about investing in a DC Clamp on meter (not cheap, IIRC mine was about £70) and you can measure what the load current is just by placing the jaws around the + cable.
Also, if you haven't already go for LED bulbs

 

[Robin]

our combined smartcharger /inverter reverts to float mode at 13.0V and 0A unless something is 'on' like the fridge, when it floats at 13v and 4A Our batteries are all HD golf cart 6V wet cell ones and under 2 years old.