# Battery Charging Float or Three Stage ?



## dipsticks (Aug 2, 2007)

[align=justify]Our AS Duetto has a CT Leisure Battery Charger from Plug-in-Power Systems model CTSAN/18A. It is called a 3 stage battery charger and has the option of running as a 3 stage or float charger.

The instructions state "On all models there is a selectable 3-stage / float charge feature. This allows a battery to be more fully and more quickly charged when the 3-stage mode is used." "To select the required mode slide the selector switch to the 'Float' or '3-stage position." "The output voltages and currents will then be set".

Float charge position constant voltage at 13.6v, variable current.

3-stage position *bulk charge constant current 18a variable voltage.*absorption mode constant volts at 14.5v,variable current.*float mode constant volts at 13.6v variable current.

Having read that and the previous posts on this subject I thought it best to use float during lay up and 3-stage during the season in use, however the instructions make this statement *"Once set the switch should not be adjusted after installation. The factory default setting is 'float charge'"*

This is what confuses me it was delivered in float position and has been used thus, does it have a memory ? has it set itself up for float only now ? any info or reccommendation gratefully received.

(Plug-in-systems do'nt make themselves very easy to speak to)

Thanks


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## hilldweller (Mar 8, 2008)

I'd take a guess it is to stop people wagging the switch up and down.

If it was doing it's 18A bulk charge and you flick it to float it might screw up the sequencing.

If I'm right, disconnecting the 240V and 12V then flicking the switch would be safe and probably just powering down the 240V then flicking the switch would also work.


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## dipsticks (Aug 2, 2007)

Thank you for that its a good point not to switch under load.

I studied further some instructions that said the absorption mode constant volts at 14.5v may be too high to directly power some 12v circuits.


What is the normal charge voltage from a vehicle alternator ? 

I can't tell exactly from the voltmeter on my car. Does anyone know if 14.5v is likely to damage anything on a normal motorhome 12v circuit.?

Thank you


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## hilldweller (Mar 8, 2008)

dipsticks said:


> Does anyone know if 14.5v is likely to damage anything on a normal motorhome 12v circuit.?


14.5V sounds right for a vehicle alternator to me - but when you crank the starter you also get hundreds of volts in tiny spikes. Anything you buy made for vehicle use will be designed to cope with this.

This had been done to death quite a bit in the past, particularly with LCD TVs that have a nominal 12V input. Some won't risk it, some say they've been doing it for years.

I've just swapped all bulbs for LED, they all come with a 16V limit. Work very well too, similar light for 10% of the current. I'd recommend warm-white from my trials, almost identical to the old bulbs. Cold white hurts.

The general safe advice is use an inverter and hope that the 240 input is tough enough to take any nasties an inverter can put out. I know one guy who killed his little LCD TV because the light load let the inverter generate a big spike ( or so we assume ).

A bit of luck comes into this !


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## CliveMott (Mar 10, 2008)

*CHARGERS*

The alternator output voltage will be typically 14.0 volts, in the range 13.8 to 14.2 volts. Any more and it will on a long run cause your battery to excessively gas. Any less and it will not achieve a reasonable charge.

The 3 stage charger will charge a battery quicker and more fully but you need to be aware that during the second phase of charging the voltage can go sufficiently in excess of 14 volts (14.5 quoted above) and this voltage will be maintained until the charging current has fallen to a very low level. This is how the charger determines that the battery is fully charged. Then the charger output voltage will fall to a maintaining or "float" voltage around 13.6 volts. When this works it works well, but some batteries after a few years use get a bit leaky so that the charge current does not fall to the very low level required by the charger to denote its charged. So they gas and gas and gas! Also 14.5 volts can be a bit much for some bits of electronic kit to contend with.
If you are sure that the battery is in good order then use 3 stage.
If you have any doubts then the constant float charge will never cause the battery to excessively gas.

C.


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## dipsticks (Aug 2, 2007)

*Re: CHARGERS*



CliveMott said:


> The alternator output voltage will be typically 14.0 volts, in the range 13.8 to 14.2 volts. Any more and it will on a long run cause your battery to excessively gas. Any less and it will not achieve a reasonable charge.C.


Thank you very much for that Clive, most informative, I'll take all that on board.

It is a new battery on a new vehicle so I am just concerned about some of the electronic kit in the vehicle. I have written to the vehicle manufacturer to ask if the 14.5v (+or - 1% is acceptable or not before I slide the switch over to three stage mode.

There is a tri-colour led that indicates which stage of the charge process is in action, which, would be useful with an older battery in the light of the above information.

Thanks again.

Kind regards.


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## rumik (Aug 19, 2007)

[quote="dipsticks] ...Having read that and the previous posts on this subject I thought it best to use float during lay up and 3-stage during the season in use, however the instructions make this statement *"Once set the switch should not be adjusted after installation. The factory default setting is 'float charge'"*

[/quote]

My Orian Zeta uses the same charger and using a mirror-on-a-stick, a piece of string and a headlamp torch (the charger is under the wardrobe floor) I have deduced that it is set to "Float" mode on the sliding switch. The LED is showing green. This is how it was built into the van and judging from the charger's location/orientation it cannot be altered easily.


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## dipsticks (Aug 2, 2007)

[/quote]

My Orian Zeta uses the same charger and using a mirror-on-a-stick, a piece of string and a headlamp torch (the charger is under the wardrobe floor) I have deduced that it is set to "Float" mode on the sliding switch. The LED is showing green. This is how it was built into the van and judging from the charger's location/orientation it cannot be altered easily.[/quote]

The green LED indicates float mode. My instructions state this is the default setting from the factory. I suspect the van builders just take it out of the box and fit it, job done.

I need a mirror also but in my van I can easily re-site the charger in order to see the LED and to slide the switch when I want to.
The Led changes colour automatically when 3 stage is selected:-red-bulk charging,yellow-absorption charging,green-float charging.

I certainly think it needs checking with the base vehicle maker and the converter before altering the setting due to the higher voltage 14.5v during absorption charge. As it says in the instructions and also Clive mentioned 14.5v may be too high for some electronic circuitry.

I had a struggle to get the instructions I can e-mail them if you wish Rumik.


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## rumik (Aug 19, 2007)

dipsticks said:


> I had a struggle to get the instructions I can e-mail them if you wish Rumik.


Yes please - as you say trying to find info on Plug-in Systems stuff is difficult. I'd also be interested what you find out about the voltage tolerance of the electrical items in your van.


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## 93763 (May 1, 2005)

I've just come across this thread, so I do not know if anyone is still watching it.

My understanding is that, when a lead-acid battery is charged to the full 14.5 volts, it gasses off a mixture of hydrogen and oxygen. This is potentially exposive if in an enclosed space such as in a motorhome. I thought this was why leisure-battery chargers are set to limit at a lower voltage, where the gassing does not take place. So changing the setting could be hazardous. (Or are modern batteries somehow different?)

I think it is good for the battery to be fully charged occasionally, but then it needs to be in a well-ventilated location while charging.

I am open to correction, but I believe this is correct.

Jonathan


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## dipsticks (Aug 2, 2007)

jonp said:


> I've just come across this thread, so I do not know if anyone is still watching it.
> 
> My understanding is that, when a lead-acid battery is charged to the full 14.5 volts, it gasses off a mixture of hydrogen and oxygen. This is potentially exposive if in an enclosed space such as in a motorhome. I thought this was why leisure-battery chargers are set to limit at a lower voltage, where the gassing does not take place. So changing the setting could be hazardous. (Or are modern batteries somehow different?)
> 
> ...


Thats interesting Johnathan.
I would think your Orian will have the same charger as our Duetto ie a Plug-in-systems CTSAN/12 or 18amp charger. 3 stage and float options Absorption Mode in 3 stage - Constant Voltage @ 14.5 volts or Float Mode-Constant Voltage @ 13.6 volts.
I know someone with an Orian that uses the 3 stage option, however we have'nt tried it yet, but, Ford tell me their smart charging system on the vehicle can charge at up to 16 volts if demand requires.
The more I look at it all the more it seems like a black hole !!
Both our batteries have a little pipe that goes through the floor of the van, maybe that is to discharge any gas of to atmosphere outside.


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## rumik (Aug 19, 2007)

dipsticks said:


> ... Both our batteries have a little pipe that goes through the floor of the van, maybe that is to discharge any gas of to atmosphere outside.


Yes the pipe is a gas vent. I have switched my charger (in an Orian Zeta) to 3-stage mode after investigation of equipment voltage tolerances.

The battery has never yet been run down very low so the charger quickly changes from bulk to absorption to float mode when switched on. In absorption mode, careful listening indicates that the battery is gassing off. It is my understanding that occasional gassing of the battery is desirable as it stirs up the acid. Of course topping up of the battery may be required from time to time.

I've also recently had a solar panel fitted so I hope that the battery will generally be kept quite well charged anyway. The solar panel regulator also operates a stepwise system with bulk charging voltage at 14.3v and float voltage at 13.8v.


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## 93763 (May 1, 2005)

dipsticks said:


> Both our batteries have a little pipe that goes through the floor of the van, maybe that is to discharge any gas of to atmosphere outside.


Yes, our last van was fairly primitive and didn't have anything as sophisticated as a vent pipe. And I have not looked in the new Orian yet.

As long as the pipe is there to vent the gas to outside, all should be fine, But, as Rumik says, you may need to top up as any gassing represents a loss of water.

Jonathan


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## mercman451 (Apr 24, 2008)

*charging*

excellent reply from clive mott,

p.s.it will also do your batteries good to run them low and recharge to full capacity 
geoff


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## CliveMott (Mar 10, 2008)

Er sorry mercman, not quite right. Nickel Cadmium batteries should be fully discharged before recharge because of memory effects. The same does not apply to Lead Acid. There is no point in discharging a lead acid battery any more than the application requires as it shortens its life.


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## dipsticks (Aug 2, 2007)

CliveMott said:


> Er sorry mercman, not quite right. Nickel Cadmium batteries should be fully discharged before recharge because of memory effects. The same does not apply to Lead Acid. There is no point in discharging a lead acid battery any more than the application requires as it shortens its life.


I'm glad this thread is still going, it is very interesting. I can't seem to get a clear answer as to the suitability of my Plug-in-systems three stage charger from anyone including Ford.
The Duetto has two batteries a Varta Semi-Traction (presume lead acid) and a Ford (brand) Calcium Silver both of which I would like to charge in three stage mode.
Ford say that their Smart charging System can charge at up to 16volts if the system requires, so would I be correct in thinking that the three stage charge as follows:

3-stage position

Bulk Mode	- Constant Current @ 12A or 18A
(Zone A) - Variable Voltage

Absorption Mode	- Constant Voltage @ 14.5 volts
(Zone B) - Variable Current

Float Mode	- Constant Voltage @ 13.6 volts
(Zone C) - Variable Current

should be OK suitable for both batteries?

I am simply concerned that since the vehicle has CAN BUS wiring, that, as the batteries remain in circuit to the vehicle whilst being charged that the voltage of 14.5 may be applied to parts of circuitry that would be isolated by the CAN BUS if the ignition was switched on.

I could be looking too deeply into this !

Any opinions/knowledge gratefully received. The most knowledgeable and helpful Clive Mott seems a likely contender.

Kind regards

Dipsticks


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## DABurleigh (May 9, 2005)

Dipsticks,

Clive's thinking about this.

"should be OK suitable for both batteries?"

Yes, but not in parallel (is one the vehicle battery and the other a leisure?).

As to silver calcium, see my post back in November:
http://www.motorhomefacts.com/ftopicp-330194.html#330194

Dave


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## dipsticks (Aug 2, 2007)

Dave
Thanks for your reply
Yes the Calcium Silver battery is the what Ford call the starter Battery and the Varta is what they (Ford) call an Additional Deep Cycle battery.
Auto Sleeper call them respectively the Vehicle and Habitation Battery!

I don't have many diagrams of the vehicle wiring but it seems to me that the Varta battery is as much part of the vehicle electrics as the Calcium Silver one is when the engine is running and only when the vehicle charge relay is released the Varta then becomes isolated from the vehicle and is then used a Leisure Battery

The drawing I have shows the starter battery (Calcium Silver) supplying:
Starter Motor and Alternator.
Passenger Junction Box power, start related.

And the Varta deep cycle battery via a bus bar suppling:
3 fused (60a) customer connections.
Passenger junction box power, non-start related.
Heated front windscreen.
Standard relay box power, non-start related.
Engine junction box, non start related.


I have to say I am a bit surprised that I don't seem to have a dedicated Leisure battery but does it matter ? Everything works fine I would just like to benefit from the full charge that can be delivered by using the 3 stage charge cycle. This is a July 2007 vehicle.

Kind regards

Pete


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## DABurleigh (May 9, 2005)

It seems to me you simply have the normal arrangement we all have but your batteries are co-located? If so on the one hand this means your habitation/ leisure battery will get a better charge than most of us (the extra distance introduces resistance). On the other, it suggests to me, but I need to think about it some more, that the batteries ought to be the same for long life.

Dave


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## Jimca (Jan 2, 2007)

*CTSAN/18A*

Just tapped into this thread
The Zig charger/transformer on my Autosleeper Symbol packed up and I have bought a CTSAN/18A to replace it. My problem is the Zig charger had two extra spade terminals, I think their wires supplied the Zig control unit.
How should I wire up the new charger?
Many thanks
Jim


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