Leisure Battery

Peter, you write :-
"As I would not intend to go lower than the 50% DOD to extend overall battery life, I would not require the 0.2C charge and would find the Sargent PX300 charger fit for my purpose if using a 100 to 200Ah AGM battery installation in my motorhome".



At anything more than about 30% Depth Of Discharge, a Sargent PX300 is still going to working flat out trying to put 40amps into 2 AGM  batteries.


I don't understand how you have worked out a Sargent PX300 will cope ok struggling to put back 40amps for an hour or two just because you have "only" dropped the battery down to most manufacturers recommended maximum deepest discharge?    



At 80% DOD it will be struggling with a 40amp draw and for a lot longer, just punishing it for 'Only a couple of hours' at 50% isn't going to change the eventual outcome for either battery or charger.




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Peter Brown wrote:The maximum output current of the pX300 is 25A it is happy to deliver that constantly and it will not give any more under any circumstances but as mentioned earlier, when a battery only discharged to 50% capacity it will not be long under the constant current charge stage for long, if at all and will go into the constant voltage stage with the current draw continually dropping as charge is accepted.

Peter, I wrote above,
"I don't understand how you have worked out a Sargent PX300 will cope ok struggling to put back 40amps for an hour or two just because you have "only" dropped the battery down to most manufacturers recommended maximum deepest discharge?
You didn't tell us how you worked it out or give any supporting evidence to back up the statement.

Now you also write, 
"....the pX300 is 25A it is happy to deliver that constantly and it will not give any more under any circumstances" 

How do you know that? Where is the documentation to back both those statements? Have you tested that to be the case? 
Have you repaired many of them and put them under stress tests overnight to see that that are working before sending them back to a customer?

Please enlighten us as to how you come to these conclusions?


A PX300 won't deliver anything like 25amps in Stage 2 at 14.3v?? It is only 300w. How do you calculate 25 amps from 300w at 14.3v? I quoted an imaginary peak of 25amps while in stage 1 at 12v to show how silly the statement was when Stage 1 is for flat batteries. 

We have already established that Stage 2 is the primary phase, even you acknowledge that now above. 

The most it will deliver normally in Stage 2 of a DIN 41773 standard is going to be just over 20amps, probably less than that continuously. If you want that verified, just do the maths.

You then write -
"when a battery only discharged to 50% capacity ......"  

ONLY??  50% DOD is the maximum most mainstream Leisure battery manufacturers recommend, that is a deep discharge. 25% DOD a shallow discharge.
Where have you seen a definition that 50% is only a shallow discharge? 

80% DOD is very deep discharge and only within the realms of some expensive super batteries, but their life is hammered if you actually go that deep, typically losing 2/3rds cycle life. Just to show I am not making that up, see the attached chart of Victron Energy batteries and how their best battery loses a massive 3,000 cycles between a 30% DOD to 80% DOD. as can be seen on the graph, the lesser batteries in the range lose the same ratio of lost cycle life.

 



I don't understand why you go to such pains to contradict and just end up showing how little you actually know.
Wouldn't it be better to just call a truce?



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In my campaign to drive change over the misselling and mislabelling of batteries I have been working with a key government department.
They have sent an email this morning to say that their testing of over 60 batteries, some of which we proposed as targets, is taking longer than expected but some results are coming through.

The email starts with, 
"In confidence, please don’t blog what follows, Although you can say the second to last paragraph in your own words or mine".


So lots I can't tell you, but that second to last paragraph states, 
"The Test results I have are startling and concern me. 
I will be interested in the explanations of these importers/distribution/rebranders when I make contact with them."

 
There is some information regarding AGM's which will come out soon as part of all this.

More details about the campaign here and what we have achieved so far :-
https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/National-Battery-labelling-standard-Progress-/49999/


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A member has reported this post! Having looked through the ‘debate’ I see no valid reason for moderator intevention. CC

CC wrote:A member has reported this post! Having looked through the ‘debate’ I see no valid reason for moderator intevention. CC

Well I, for one, am pleased at that CC - Allan Evans has proved on many occasions that he has a considerable knowledge of battery and charging technology. He is also one of only a handful of people nationwide that has been prepared to uncover actual evidence on issues like leisure battery life and to take action to remedy the doubtful selling/advertising practices of some companies and even organisations such as the NCC who are supposed to be offering impartial testing and advice on such matters -  all of this will ultimately prove beneficial to Motorhomers.

David

AllaFEvans wrote:The Sargent PX300 isn't bad, but we would suggest it is about the lowest spec most motorhome owners should look to buy. Even though it is multi stage, it is single technology meaning it doesn't have separate charge profiles for Gel, AGM or Lithium batteries. 
The relatively recently introduced Sargent  201 and it's smaller sibling the 151 are just 13.5v fixed voltage power supplies of 10amp and 16amp. 
They won't properly charge any battery, which as you know likes a 'boost' of 14.4v. 
The 201 and 151 are used in the EC155 and  EC160 type units.

Hi Allan, thank you and others for a fascinating discussion. Its making the tiny technical part of my brain work overtime. Some time ago, on this thread, you refer to the 151 as used in the EC155 [as above]. My MH is fitted with the EC155 PSU.

I found the following information in my AS handbook. It differs slightly with your findings as above, but clearly acknowledges your observation that the voltage supplied by the unit is insufficient for a required battery 'boost'.

Edited Quote:
The EC155PSU incorporates a fixed voltage battery charger / power converter...This module supplies 13.8V DC to the leisure equipment up to a maximum of 12 Amps (155 Watts), therefore the available power is distributed between the leisure load and the battery, with the leisure load taking priority as per the following example:
Leisure load        Available power for battery charging
      3A                                          9A
      6A                                          6A
      9A                                          3A
     12A                                         0A

And something similar for the EC328, as I recall!

MelB wrote:

AllaFEvans wrote:The Sargent PX300 isn't bad, but we would suggest it is about the lowest spec most motorhome owners should look to buy. Even though it is multi stage, it is single technology meaning it doesn't have separate charge profiles for Gel, AGM or Lithium batteries. 
The relatively recently introduced Sargent  201 and it's smaller sibling the 151 are just 13.5v fixed voltage power supplies of 10amp and 16amp. 
They won't properly charge any battery, which as you know likes a 'boost' of 14.4v. 
The 201 and 151 are used in the EC155 and  EC160 type units.

Hi Allan, thank you and others for a fascinating discussion. Its making the tiny technical part of my brain work overtime. Some time ago, on this thread, you refer to the 151 as used in the EC155 [as above]. My MH is fitted with the EC155 PSU.

I found the following information in my AS handbook. It differs slightly with your findings as above, but clearly acknowledges your observation that the voltage supplied by the unit is insufficient for a required battery 'boost'.

Edited Quote:
The EC155PSU incorporates a fixed voltage battery charger / power converter...This module supplies 13.8V DC to the leisure equipment up to a maximum of 12 Amps (155 Watts), therefore the available power is distributed between the leisure load and the battery, with the leisure load taking priority as per the following example:
Leisure load        Available power for battery charging
      3A                                          9A
      6A                                          6A
      9A                                          3A
     12A                                         0A

Melb,  If you do the maths a 155w charger at 13.8v can supply a max 11.2amps - 155 / 13.8v = 11.2 and that assumes 100% efficiency, so they could never have been 12amp chargers.

The quoted wattage is usually that consumed by the charger from the mains, just like is quoted for a kettle or electric fire.
But in a charger the 230v wattage will be subject to 'losses' because of the inefficiency of the charging process which is typically only 85% efficient. 

When you knock off the 15% inefficiencies, it will create a more realistic output at the '12v' terminals, like 'our' 10 amps. Just under 10 amps is what we see on the workbench. 


We suspect the specification supplied by Sargent has changed a few times and the documentation hasn't kept pace? (That is a nice way of saying it isn't right)

If you look at this website : https://www.jacksonsleisure.com/caravan-motorhome/electrical/batteries-chargers/sargent-supercharge-151-leisure-battery-charger/   they sell the 151 and quote a 13.5v output, not 13.8v.

Jackson Leisure also list the 201 also as 13.5v and this is the voltage output of the the more recent manufactured models.

The Sargent website itself just says the 151 is a 150w charger, it rather sneakily doesn't quote amps or volts. 

However the Sargent website manuals do list the 201 as 13.5v, 200watts  and '16' amps. Yet 200w /13.5v = 14.8amps, and that is before you take off the 15%. 
See :  https://sargentltd.co.uk/tech-support/article/23/download/231

Most of the newer sales outlets quote a 13.5v output which we suspect many were from the start.

Maybe you can imagine how 2 x AGM batteries that want 40amps and 14.7v will react to 13.5v and 9.9 amps? 
You will note that the NCC Verified battery scheme doesn't warn you of the disaster that will be about to hit your pocket if you took their advice in their heavily promoted AGM battery sections? 
When we estimate that around 50% of the Caravans and Motorhomes on the road have low current 13.8v, or less, chargers you can see why we want the Caravan clubs that started  the Verified battery scheme to put up some warnings.

We did get the Motorhome and Caravan Club to put out a warning at the end of last year saying not to fit AGM's unless you are certain your charging systems are appropriate, but it went out in a small column at the back of the magazine. At least it was a start.


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inspiredron wrote:And something similar for the EC328, as I recall!

Can you elaborate further on what you mean about the Ec328?

I recall a similar statement / table regarding the max output (20A?) being spread across current leisure usage and charging. My handbook is not to hand at present so I cannot check but they are available on the A/S website.
The point that I was gently making was that it implies a MAXIMUM output from the charger of 20A.

I have now checked my handbook. The charger info is for the EC325 and quotes maximum ratings as 325W and 25A (not 20A as above). It shows a table that splits the 25A between the leisure load (which appears to be limited to 12V and disconnected from the leisure battery) whiich takes priority with the balance of the 25A available for charging. I obviously realised when I bought the van that it was the wrong instructions for my EC328 as I downloaded the Sargent manual for the 328. The appropriate page of that pdf is headed EC328 but the relevant section of the page is headed EC500! However the content is precisely similar save that the wattage is stated as 300W not 325W. There is a reference to fusing individual batteries at 20A and not exceeding total fusing of 40A (which the spec canno deliver!). However there is fan cooling which is severely inhibited by the location of my charger at the back of the wardrobe, shrouded in clothing and with no ventilation!
I take a very simple view on all this. I consider it very unlikely that either the Peugeot alternator or the Sargent charger is over-engineered for the vehicle's original equipment. For Peugeot that means ONE battery (designed as a delivery van) and for Sargent TWO. I reckon that the alternator is therefore likely to be stressed to charge two batteries, let alone three and the Sargent is obviously limited by its 25A maximum. If faced with a pair of flat leisure batteries I don't know whether the Sargent would limit them to 12A each or whether it would massively overheat in trying to give more than it can. To subject it to that with the cooling restrictions that exist would in my view be madness. Faced with THREE batteries I shudder to think what the alternator would do. But luckily I have never been tempted to add a second leisure battery as I have never felt the need. So, to me this is all very interesting and technical but of no direct relevance.
I also wonder if the continual argument, at times verging on the acrimonious, helps the understanding or causes greater confusion for those less expert in the science.
My simple approach has resulted in both my batteries now entering their eighth year and that despite the fact that on one occasion, early in their life I allowed them to drop to TWO VOLTS because I did not appreciate that modern vans have a much higher "quiescent" draw than did my 2001 Hymer with its Electroblock EBL99. Consequently "full" charge is now 12.4V, and I recharged about every 6 weeks by which time both batteries have dropped to 11.9V. Maybe I have been lucky?
That was a very rambling edit - Sorry!

I am no expert in science. Can't make head not tail of any of this. All l know is both my batteries are fine. Vehicle and habitation. Don't even know what make they are. I have had my van six years and it is an 06 model. I have a solar panel and l use it from March to November. If anything happens I'll just as my amazing enginner Gazavan what to do. Oh help. Touch wood l haven't spoken to soon.

MelB wrote:I found the following information in my AS handbook. It differs slightly with your findings as above, but clearly acknowledges your observation that the voltage supplied by the unit is insufficient for a required battery 'boost'.

Edited Quote:
The EC155PSU incorporates a fixed voltage battery charger / power converter...This module supplies 13.8V DC to the leisure equipment up to a maximum of 12 Amps (155 Watts), therefore the available power is distributed between the leisure load and the battery, with the leisure load taking priority as per the following example:
Leisure load        Available power for battery charging
      3A                                          9A
      6A                                          6A
      9A                                          3A
     12A                                         0A

AllaFEvansMelb,  If you do the maths a 155w charger at 13.8v can supply a max 11.2amps - 155 / 13.8v = 11.2 and that assumes 100% efficiency, so they could never have been 12amp chargers.

The quoted wattage is usually that consumed by the charger from the mains, just like is quoted for a kettle or electric fire.
But in a charger the 230v wattage will be subject to 'losses' because of the inefficiency of the charging process which is typically only 85% efficient. 

When you knock off the 15% inefficiencies, it will create a more realistic output at the '12v' terminals, like 'our' 10 amps. Just under 10 amps is what we see on the workbench. 


We suspect the specification supplied by Sargent has changed a few times and the documentation hasn't kept pace? (That is a nice way of saying it isn't right)

If you look at this website : https://www.jacksonsleisure.com/caravan-motorhome/electrical/batteries-chargers/sargent-supercharge-151-leisure-battery-charger/   they sell the 151 and quote a 13.5v output, not 13.8v.

Jackson Leisure also list the 201 also as 13.5v and this is the voltage output of the the more recent manufactured models.

The Sargent website itself just says the 151 is a 150w charger, it rather sneakily doesn't quote amps or volts. 

However the Sargent website manuals do list the 201 as 13.5v, 200watts  and '16' amps. Yet 200w /13.5v = 14.8amps, and that is before you take off the 15%. 
See :  https://sargentltd.co.uk/tech-support/article/23/download/231

Most of the newer sales outlets quote a 13.5v output which we suspect many were from the start.

Maybe you can imagine how 2 x AGM batteries that want 40amps and 14.7v will react to 13.5v and 9.9 amps? 
You will note that the NCC Verified battery scheme doesn't warn you of the disaster that will be about to hit your pocket if you took their advice in their heavily promoted AGM battery sections? 
When we estimate that around 50% of the Caravans and Motorhomes on the road have low current 13.8v, or less, chargers you can see why we want the Caravan clubs that started  the Verified battery scheme to put up some warnings.

We did get the Motorhome and Caravan Club to put out a warning at the end of last year saying not to fit AGM's unless you are certain your charging systems are appropriate, but it went out in a small column at the back of the magazine. At least it was a start.


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AlaFEvans. Thank you for your in-depth, technical, clarification on the subject. Unlike Inspiredron I was, some time ago, tempted to add a second leisure battery. I finally, thankfully, opted for a 100W SP to provide extra power to the batteries, that I required. After reading your contributions on this forum I believe I made the correct choice.

inspiredron wrote:

I also wonder if the continual argument, at times verging on the acrimonious, helps the understanding or causes greater confusion for those less expert in the science.  

Inspiredron, I accept most of what you say and you are probably right that the continual arguing "causes greater confusion for those less expert in the science".


However it was important to help the two other key people in the debate understand how Motorhome chargers work because Brodco's comments and these of Peter stem from another thread on battery charging where they attacked the contents of my website saying it was 'wrong'.
That thread became very nasty and was incorrectly, IMO, locked by a moderator. I can't find the thread any longer, otherwise I would extracted the attack on the web page contents and a lot of other stuff about smart/intelligent chargers.

As a result the 'discussion' was left unfinished and was resurrected by Brodco above and once agian supported by Peter, who then had comments and a post removed by a moderator. 
Because they thought all the charging of a 3 stage charger was done by the first stage and it was this stage that charged the battery fully they did not understand the key importance of motorhome and Caravan Stage 2 'timers' and how they are critical when adding a second battery. 

It is because of these timers that adding a second battery can lead to a 10 fold increase in charge time of days, not the 2 fold increase most might expect. See the explanation of why here  : http://www.aandncaravanservices.co.uk/how-does-a-charger-work.php
It was this explanation that was attacked due to their lack of understanding.

At least Peter now accepts that the 1st Stage is only for flat batteries, which Motorhome batteries should never be, and that stage 2 is key. 
Hopefully Brodco now also accepts how motorhome chargers work and how they are different to Car battery chargers and the matter will be laid to rest once and for all?

rose49f wrote:I am no expert in science. Can't make head not tail of any of this. All l know is both my batteries are fine. Vehicle and habitation. Don't even know what make they are. I have had my van six years and it is an 06 model. I have a solar panel and l use it from March to November. If anything happens I'll just as my amazing enginner Gazavan what to do. Oh help. Touch wood l haven't spoken to soon.

Rose49f, it is usually chemically impossible for a battery to be 'Fine' if they are 6 years old and have been used to any decent degree.

Each time a battery is charged and discharged (a charge/discharge cycle) a little bit of the battery capacity is lost, this applies to all Lead Acid batteries : Wet, Gel and AGM.

So a battery eventually loses capacity until it becomes 'Exhausted'. The industry regard a battery as being 'exhausted', reached End Of Life when less than 80% capacity is available from a fully charged battery.

 
Even though it may hold it's charge and perform normally in all other respects, it will have the capacity of a smaller battery. 

This gradual deterioration is typified when you hear someone say, "the batteries used to last 3 days off grid but now I only get two days".


A battery normally only 'fails' if it is used beyond the exhausted state and then suffers some physical damage like paste shedding, shorting, sulphation, etc.

For example on each discharge, a typical budget 100Ah wet battery might lose 0.2Ah so drops to 99.8Ah capacity on the first discharged. So by the time 100 cycles have been used, the battery may be down to less than 80Ah capacity.

By 200 cycles, it may be the equivalent of a 60Ah battery, with just 10Ah available to be used.

Once a battery loses more than 20% capacity, it's decline accelerates.


The above example is not exact and scientifically accurate, as many factors affect how a battery performs, but it does provide a good guide.

This loss of capacity is impacted by several factors, Primarily : battery chemistry, quality of construction, technology, temperature and usage but I would still suspect it may be worth putting yours through a 'Capacity' test to help avoid sudden failure?

Battery used a lot over the 9 months l use the van. Festivals, horse trials but also l go on Ehu. When it goes l think I'll get the same one. So six years is good for a battery you say.

rose49f wrote:Battery used a lot over the 9 months l use the van. Festivals, horse trials but also l go on Ehu. When it goes l think I'll get the same one. So six years is good for a battery you say.

Yes six years is outstanding for a conventional battery, if it is still delivering better than 79% capacity.

I'll have to touch wood again.

Just a reminder about the importance of wiring inverters, etc across both batteries.

We worked on a motorhome on Friday that had two exhausted Leisure batteries just over 2 years old. The front one was down to 57% capacity and the back one down to 76% capacity. The front one was also beginning to show signs of structural failure to the Plates.

All the power take off (and Solar connection) were to the front battery even though the two batteries were side by side with 2 feet of cable linking them.
 
It is important that Solar, Inverters, etc are applied or taken from across both batteries, the positive on one battery and the Negative off the other battery if you want to get maximum life and capacity from the batteries.
See photo above.

In this installation the front battery had been doing all the work and the batteries had clearly expired at least 9 months ago but their condition masked by the Solar set-up.

Only during December and January when the Solar made little contribution did the batteries real state make itself known.

I would guess the front battery dropped below the industry definition for an exhausted battery of 80% capacity early 2018 and has just degraded since?

While the rear battery might have what sounds like a lot of capacity remaining at 76%, bear in mind that following the usual advice of  'leaving 50% in the battery' means that only 26% Ah was actually available on each charge, or just 22Ah in this case with 95Ah batteries.  


We are seeing more of these lately, yet balancing the load can give you significantly longer battery life and extended capacity over a poor set-up, but is so easy to remedy yourself.
All you need do is just check the habitation batteries and make sure all paired wiring (like one black or one Red) go across the two batteries. 
If any are in the wrong position (especially Solar or Inverters) then just relocate them to the other battery terminal, as above.


Ideally take all power points direct from the Sargent Power Controller so it can isolate them when the control panel is shut down.