Solar controller for calcium batteries

[kalanka]

I was on the point of buying the DB 1C controller from SunWorks (as recommended by Vyv) but checked and they advised me that it doesn't cope with calcium batteries.

I have 2 + 1 batteries to the following spec.

Manufacture Alphaline Volt 12 AH75

Cold Cranking 610

Battery Type Sealed Calcium

Deep Cycle

I have a preference for a dual charger and one that also displays the voltage of each bank. Any suggestions? Can anyone explain why calcium batteries seem to present this problem? Would a controller that claims to deal with "sealed" batteries be suitable?

Thanks

 

[RichardS]

.... they advised me that it doesn't cope with calcium batteries.

Would a controller that claims to deal with "sealed" batteries be suitable?

That doesn't seem right to me. I can't imagine that any current controller would not be able to cope with sealed batteries, calcium or not.

Some, like mine, are configurable so you can set a higher initial charge voltage for non-sealed batteries but many simply charge at a maximum of 14.4V to suit both types. I assume the Sunworks is not configurable so surely it uses 14.4V for all batteries.

Richard

 

[William_H]

You do not specify what solar panel size you have. In practice with smaller panels and larger batteries the controller is a bit redundant in that it is designed to cut charge when the battery is fully charged to avoid over charge.( assuming not an MPPT type) But if the panel, its orientation and amount of sunshine mean that only a dribble of charge comes at the best of times then over charge is not a problem.(even with MPPT) So if a controller specifies that it will charge at 14.4 volts then in fact that is the maximum volts it can bring the battery to. Whether it acheives that is often quite doubtful. Monitor actual battery v0ltage on solar charge) So I would suggest use any available controller limiting voltage to about 14.4 volts and if you are really concerned about overcharge of calcium batteries (not likely) then reduce the solar power. (disconnect some panels or partially cover the panel while monitoring current ) good luck olewill.

 

[vyv_cox]

As I was looking up the type of battery I have I was thinking of the reasons for SunWorks' statement, then I read William_H's post and realised it had already been said. I think he is exactly right. I have three Bosch S5103 domestic batteries with 125 watts of solar power. The reality is that in Greece in the height of summer, running a fridge full time, the batteries are never overcharged. Indeed, I read posts from a battery expert here and on the CA forums that suggest that batteries can never be 100% charged except by mains power.

My sealed batteries are three years old, used extensively full time for half the year and remain in excellent condition. Many full time liveaboards reckon that batteries used this way have a life expectation of little more than three years anyway, so I think my setup is working well.

 

[Sailingsaves]

Calcium, sealed batteries are prone to being overcharged by older charging systems - fortunately Halfords have a long guarantee on their batteries and replaced on of mine that had suffered overcharging by normal alternator. Even though sealed, overcharging leads to gassing and hence loss of electrolyte that one cannot observe.

Halfords do not know that calcium batteries need special charging systems so probably have a lot of returns before the guarantee wears out.

The batteries prefer a slow (or lower Amps input), lower than usual (not 14.5V) charge voltage than regular lead plate batteries.

I have forgotten a lot of the specifics, but some quick research should be easy.

(my calcium battery was showing signs of wear - again - but borrowing a CTEK smart charger (that the manual stated was suitable for Calcium plates) sorted it and rejuvenated it.

 

[charles_reed]

Can't get over the perceived arcane mysteries surrounding batteries and their charging.
From my previous experience, calcium is an alternative to antimony for making battery plates.
Because plates using this alloy are slower to charge, they are less likely to suffer from water-loss. Result, nearly all sealed batteries use a calcium amalgam plate.
The claims that "Halfords don't know.." are manifestly ridiculous - Halfords only know what their battery manufacturer tells them - if a simple on-off controller "isn't suitable for calcium batteries" it's not suitable for purpose and shouldn't be on the market.
My observations are that neither a "normal" alternator controller or a PV array will fully charge a battery set - you have to rely upon a smart charger which goes through an absorption/equalising phase. Whether or not such a lack of charge increases the chance of sulphation is a source of endless argument between "Battery Experts", all I know is that on a car (with no such luxury) a battery lasts 10 years and on a boat only 5 (though the big domestic has achieved a 10 year life).

 

[macd]

You're not comparing like with like Charles. It's self evident that a boat starter battery enjoys a similar charge regime to a car battery. A domestic battery does not.

 

[GrahamM376]

You're not comparing like with like Charles. It's self evident that a boat starter battery enjoys a similar charge regime to a car battery. A domestic battery does not.

Not always the case. Silver calcium batteries are used on cars with smart charging systems and the alternator has additional contacts to control a complicated charging regime based on load. Some info here - http://www.qh.com/assets/_files/documents/oct_13/QH__1382620262_Tech_Bulletin_-_TB0010_-_FRA.pdf

The last place I would seek technical advice is a general motor trade retailer such as Halfords as staff generally only have a little knowledge about a wide range of products. Personally, I prefer to keep things simple and stick to lead acid which will accept abuse better than any other.

 

[Sailingsaves]

... Halfords ... little...knowledge... Personally, I prefer to keep things simple and stick to lead acid which will accept abuse better than any other.

Hear, hear !

 

[kalanka]

Interesting comments so far…. My panels are small (at present) only 40W with main charging on passage coming from an Aquair which is not regulated. Despite my stated location on this forum the boat is currently in Tenerife and heading south and west so the solar charging will be a bit more powerful than on a wet day in Tobermory!

I would like the option to leave the boat for a month or 6 weeks with the panels keeping the batteries charged. I take it nobody thinks this should be done without a regulator/controller?

 

[RichardS]

Interesting comments so far…. My panels are small (at present) only 40W with main charging on passage coming from an Aquair which is not regulated. Despite my stated location on this forum the boat is currently in Tenerife and heading south and west so the solar charging will be a bit more powerful than on a wet day in Tobermory!

I would like the option to leave the boat for a month or 6 weeks with the panels keeping the batteries charged. I take it nobody thinks this should be done without a regulator/controller?

I agree that a 40W panel in Tenerife could potentially overcharge the batteries unless you have a massive bank. There was a thread a couple of weeks ago and several forumites, including me, use this controller or a similar version to separately control two separate battery banks.

http://www.ebay.co.uk/itm/20A-Solar...21293914740?pt=UK_Gadgets&hash=item1c3dae4274

This will work fine with sealed or open batteries.

Richard

 

[GrahamM376]

I agree that a 40W panel in Tenerife could potentially overcharge the batteries unless you have a massive bank. There was a thread a couple of weeks ago and several forumites, including me, use this controller or a similar version to separately control two separate battery banks.

http://www.ebay.co.uk/itm/20A-Solar...21293914740?pt=UK_Gadgets&hash=item1c3dae4274

This will work fine with sealed or open batteries.

Richard

But how does that regulator perform in practice? According to the spec. it seems to limit boost charge 14.4v to 30 mins, after which it drops to float voltage 13.7 volts. At that regime, it would take days to charge my 480ah, even off load.

 

[charles_reed]

You're not comparing like with like Charles. It's self evident that a boat starter battery enjoys a similar charge regime to a car battery. A domestic battery does not.

I am. For the last 25 years I've never had a dedicated engine start battery and never been unable to start the engine.
I'm always suspicious of anyone who uses "self-evident" in an argument as it usually means they've not actually thought it through.
It's probable that a car-battery, is always being charged, but never fully charged by the car alternator - it's my purely domestic forward battery which outlives its dual-purpose brethren.
I have to reject your comment as being totally contrary to my experienced facts.

 

[Hadenough]

But how does that regulator perform in practice? According to the spec. it seems to limit boost charge 14.4v to 30 mins, after which it drops to float voltage 13.7 volts. At that regime, it would take days to charge my 480ah, even off load.

Don't know the technical detail but in practice I have that controller for 240W of solar charging a 450AH bank (split 150 / 300). In Britain this summer as permanent livaboards it has kept up with all our domestic needs including a fridge, only rarely, maybe every ten days, needing a boost from shore power or the genset.

 

[macd]

I am. For the last 25 years I've never had a dedicated engine start battery and never been unable to start the engine.
I'm always suspicious of anyone who uses "self-evident" in an argument as it usually means they've not actually thought it through.
It's probable that a car-battery, is always being charged, but never fully charged by the car alternator - it's my purely domestic forward battery which outlives its dual-purpose brethren.
I have to reject your comment as being totally contrary to my experienced facts.

Bit of thread drift, and apologies to all for that, but for all but your somewhat singular set-up (which you might helpfully have mentioned at the outset), the "self-evident" stands as exactly that. Car batteries might not have sophisticated charging regimes but (barring specific problems) they cycle so shallowly that they last for aeons. I fully expect that this reflects the experience of most on here, if not that of your esteemed self.

 

[VicMallows]

According to the spec. it seems to limit boost charge 14.4v to 30 mins, after which it drops to float voltage 13.7 volts. At that regime, it would take days to charge my 480ah, even off load.

That is similar to my experience with other 'solar regulators'. They charge at maximum rate until a voltage of 14.4 is achieved, and then maintain this for a set period (typically 30-60 mins) before dropping to 13.8v. This has presumably been determined as a suitable regime for their original design application (often street lamps/roadsigns/etc) where the battery capacity and expected discharge are known factors.

On a boat we usually have a large battery capacity, but a completely unpredictable discharge pattern. A normal solar regulator has no way of knowing how much charge needs to be replaced and can only make a guess based on the voltage across the battery rising (to 14.4v). If the discharge has been significant, the battery although at 14.4v, will need much longer at that voltage to fully recharge.

An ideal regulator would know how many Ah had been taken from the battery and how many to put back in before dropping to float. When on board I achieve this manually by overriding the regulator and monitoring the Ah counter.

 

[RichardS]

That is similar to my experience with other 'solar regulators'. They charge at maximum rate until a voltage of 14.4 is achieved, and then maintain this for a set period (typically 30-60 mins) before dropping to 13.8v. This has presumably been determined as a suitable regime for their original design application (often street lamps/roadsigns/etc) where the battery capacity and expected discharge are known factors.

As 14.4V is the normally accepted gassing voltage for lead acid cells one would presumably not want to hold the voltage at 14.4V or higher for very long, particularly with sealed batteries where any loss cannot be replaced.

Richard

 

[GrahamM376]

As 14.4V is the normally accepted gassing voltage for lead acid cells one would presumably not want to hold the voltage at 14.4V or higher for very long, particularly with sealed batteries where any loss cannot be replaced.

Richard

Charging regime for Trojan T125 (open lead acid) - Absorption 14.1 - 14.7v, Float 13.2v, Equalize 15.48v. The reg mentioned above has equaliize voltage lower than recommended Absorption voltage for the batteries. I sometimes use reset button to overide my regs timings.

 

[sailinglegend420]

As 14.4V is the normally accepted gassing voltage for lead acid cells one would presumably not want to hold the voltage at 14.4V or higher for very long, particularly with sealed batteries where any loss cannot be replaced.

Batteries need to reach the gassing voltage to stir up the electrolyte and stop stratification, but this gassing is very light and the hydrogen and oxygen will usually combine to form water and not escape. Only when the batteries are fully charged does the energy from the 14.4v increase the gassing significantly which would then vent out. That is why multi-stage chargers that go up to 14.4 v and hold the voltage there must then drop to float after a timed period to protect the batteries. Even 14.4v auto alternators never stay at 14.4v for long because the voltage is reduced by the built in temperature regulator as the alternator heats up.

 

[charles_reed]

One may be straining at gnats - my experience of 330w of PV panel and an MPPT controller, into 330ah of lead-acid, is that the PV panels never totally recharge the batteries - the BZ500 is set to go onto float @ 14.4 volts and usually puts in a charge @ +1.0v of the system voltage.
I only use shorepower about x4 a year and the charger never has gone into bulk charge, but straight into equalising, suggesting the batteries are sensed as being close to charged. Gross gassing never on the open cell battery - just occasional lazy bubbles between 13.7 and 14.1 at the battery terminals. Can't pass any observations on the sealed ones, except that the last one only lasted 50 months and failed on #1 cell refusing to accept charge. On the whole the sealed batteries have about half the life of open ones.
Not an "occasional use" boat - 6/12 liveaboard in Greece and <10 days @ anchor with no engine run.
It's certainly an article of faith with desulphation cycle fans that the bursts of high voltage are what breaks up the inert deposit and "recovers" the storage capacity - I am inclined to think that sulphation is the result of cumulative undercharging (rather like the hysteresis effect with NiCd cells).
Certainly Trojan used (about 15 years ago) to recommend, on their website, an annual "service" of their industrial units, involving two cycles of fast, complete, discharge followed by immediate recharge. Reports on this (on setsail.com) reported an increase in claimed capacity after the operation. All very interesting and rather like "the Children of the Book" each of the faiths claim theirs is the only True Word - as with religion, we'll probably only find out in the afterlife.
Certainly all this battery theology is likely to be overtaken by the incursion of LiFeXxx technology - in fact Charles Sterling has incorporated a lithium charge cycle in his latest smart charge and there is at least one site on cruisersforum devoted to this one subject (mainly in the US).