Deep Cycle Battery charging

Submitted: Monday, May 05, 2008 at 18:07
ThreadID: 57303 Views:9567 Replies:10 FollowUps:48
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Howdy All, I was just browsing through the archives on charging deep cycle batteries & now need some input please from you blokes with a bit of knowledge on this subject.
We have an on road van which we have just fitted with a 95 amp deep cycle battery which supplies our lights, telly, & water pump.

We have no means of charging the battery unless we are on a 240v powered sight. My intention was to use a "trickle" charger that i bought from woolies about 25 - 30 years ago!! Well......... I am being honest as I do not understand these matters. LOL
Anyway, I came across post # 49784 in the archives which does not represent our situation, but...... there was a response from Disco that referred to a link "battery charging & Battery chargers"
which now has alarm bells ringing for me.
I suppose without all of the above info, what I realy need to know is what sort of 240 volt plug in charger should I have to charge such a battery to max efficiency? Thanks heaps for any help
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Reply By: Notso - Monday, May 05, 2008 at 19:17

Monday, May 05, 2008 at 19:17
There are heaps of issues with putting the battery in the van, did you get some advice before doing it.

Do you have a 12 volt power supply in the van. Other than the battery that is?

You will need a "Smart Charger" They will cost anywhere from 200 to 300 dollars for a half decent brand, but I suggest some professional help with the set up.



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Follow Up By: Member - barry F (NSW) - Monday, May 05, 2008 at 19:40

Monday, May 05, 2008 at 19:40
Thanks for that, the van is designed for and has provision for a deep cycle battery. Lights, pump, exhaust fan etc. are all 12V. all we had to do was buy the appropriate battery ("sealed etc) & stick it in the box provided & connect to leads provided by the manufacturer.
Cheers
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Follow Up By: Notso - Monday, May 05, 2008 at 20:16

Monday, May 05, 2008 at 20:16
So are you sure it's not being charged by the vans power supply?

Some van manufacturers put in a power supply/charger.

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Follow Up By: obee - Monday, May 05, 2008 at 21:37

Monday, May 05, 2008 at 21:37
put a meter on it while the motor is running. If it shows 13.8 volts then it is being charged from the alternator. That is unless the battery is dead flat and you need to wait a little for some resistance to build up.

Then read all the stuff in the "search by topic" column next to this one.
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Follow Up By: Ianw - Monday, May 05, 2008 at 22:11

Monday, May 05, 2008 at 22:11
If it shows 13.8 volts it is being trickle charged only! Be prepared to travel for several days to fully charge your battery!!

Ian
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Follow Up By: Member - Phil G (SA) - Wednesday, May 07, 2008 at 12:28

Wednesday, May 07, 2008 at 12:28
Ian,
You might be interested at what happens at 13.8V. It all depends on how far discharged the battery is. Most N70 batteries will pull 20-30 amps at 13.8V if they are half discharged and the battery is in good nick. And many alternators charge at 13.8ish when things have warmed up. Definitely not a Trickle!!

13.8V is the commonly quoted float charge (not trickle), which means you can leave a battery on 13.8V continuously without damaging the battery.
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Follow Up By: Ianw - Wednesday, May 07, 2008 at 19:12

Wednesday, May 07, 2008 at 19:12
Pre-bloody-cisely!!!
A float charge is designed to replace the self discharge current of a fully charged battery only. At the most it may be 1/2 to 1 amp.
(a trickle charge) It cannot hope to charge a battery fully in the short term. Maybe 13.8v will charge a flat battery to possibly 50%, but nobody in their right mind would say that it was charged. A 100 amphour battery would need another 60 hours of "float" charge to bring it anywhere near 100%.
You are right in saying that many (most) alternators reduce the voltage to 13.8ish once everything is all warmed up. This is because the battery has also warmed up and needs less voltage to charge it. THE BATTERY IN THE VAN IS STILL ICE COLD!! It needs more than 14.4 volts to charge it. If you can heat the van battery to the same temp then it will work. Not practicable!!

Ian
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Reply By: Goldfind (Dunsborough) - Monday, May 05, 2008 at 19:29

Monday, May 05, 2008 at 19:29
Barry, Have a look at the ctek from sweden. All fully auto to keep the battery in good fully charged condition.
go to www.ctek.com
AnswerID: 302188

Reply By: Robin Miller - Monday, May 05, 2008 at 19:43

Monday, May 05, 2008 at 19:43
Hi Barry

There are many automatic chargers that will charge your battery effectively , like the Ctek already mentioned and the key thing is that they monitor the battery voltage and reduce the charge
to a floating or long term charge voltage when the battery requires it.
This is what your woolies one doesn't do!


You have probably read about those with 3 or 4 or more stages and these work well usually but what you pay for is a faster charging time and not in your words "max efficency".
Fast charging usually means more control electronics and protection circuits.

Many such chargers also have more settings for the finer differences between battery types and can even monitor the batteries temperature as it charges and compenstate for it further
quickening the charge time.

But I'll assume you want something pretty basic - just connect it up and forget and at a reasonable price.

Hence I suggest a Jaycar MB3612 retail $99 as a good workhorse, which is sized well for your battery.

If you want something fancier with more features then go for there MB1620 at $169
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Follow Up By: Member - barry F (NSW) - Monday, May 05, 2008 at 19:56

Monday, May 05, 2008 at 19:56
Thanks Robin, yep you summed it up, alls we need is a basic unit that we can afford without all the bells & whistles. Many thanks.
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Follow Up By: Nomadic Navara - Tuesday, May 06, 2008 at 16:49

Tuesday, May 06, 2008 at 16:49
Robin

I have just tried searching for those numbers in the Jaycar catalogue and nothing shows up. Are you sure they are current stock?

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Follow Up By: Robin Miller - Tuesday, May 06, 2008 at 21:06

Tuesday, May 06, 2008 at 21:06
Hi Peter

I think a dash is required to search, I just put MB-3612 into www.jaycar.com and it came up ok.

The price came up as $54.95 then I noted at top of screen it said USD , when I searched again after clicking $AUS it was $99 again.

Interesting
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Follow Up By: Robin Miller - Tuesday, May 06, 2008 at 21:11

Tuesday, May 06, 2008 at 21:11
Should have added that there is a www.jaycar.com.au site also
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Follow Up By: Nomadic Navara - Wednesday, May 07, 2008 at 00:49

Wednesday, May 07, 2008 at 00:49
Robin

Indeed the MB-3612 comes up in both sites. I was looking for the MB1620. It does not matter whether I used the form as shown here, a hyphen is inserted or a space inserted between the numerals, I can not locate it. Maybee I should have checked both models.

However I would like to add that I would only use the MB-3612 on flooded batteries. Although they say it "*Suits Sealed or Un-sealed Lead Acid Batteries" it does not indicate there is any means of adjusting the output voltage. There is only a mention that the output voltage (or Equaliser Charge) is 14.4 V. This is suitable for flooded batteries, the better quality chargers make provision for a lower output for sealed and AGM batteries (check the Ctek specifications.) I would not use this on sealed batteries as I would be concerned that it would overcharge them and dry them out. It would be even more harsh on gel cells.

This is the difference between the better quality chargers and the MB-3612. The better chargers permit you to tailor the output voltage for several types of batteries, This one is only for flooded batteries (the ones with removable caps on the top.)

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Follow Up By: Mike Harding - Wednesday, May 07, 2008 at 07:47

Wednesday, May 07, 2008 at 07:47
PeterD:

What makes you believe 14V4 is too high a voltage for cyclic charging of AGM batteries?

Mike Harding
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Follow Up By: Robin Miller - Wednesday, May 07, 2008 at 08:30

Wednesday, May 07, 2008 at 08:30
Hi Peter

The number for a multistage unit should be MB-3620 according to my 2008 catalogue, to my knowledge though none of these have settable output volts.

Where I have to design systems requiring max battery life I would not use a unit that does not take into account both the exact battery type, voltage and also ambient temperature via attached sensors.

But this question was about a better choice for the stated circumstances, not about the most sophisticated charger.

If you look at the extra cost of a CTEK charger against the savings in increased battery life then you actually come of worse using a ctek for your normal AGM or Flooded car battery type.

I would have no concerns about drying these batteries out with the MB-3612 charger , but it is good to check your batteries specs as you suggest as I agree there can be significant manufacturers variation.
But re GEL cells - I am looking at one right now (Jaycar Diamec brand) and it states on it that it requires 14.4-15.0 volts for constant voltage charge and 13.5-13.8v for standby use, so you could be pretty happy with using an MB-3612 on it.








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Follow Up By: Member - bushfix - Wednesday, May 07, 2008 at 09:58

Wednesday, May 07, 2008 at 09:58
G"day Mike,

my 100 A/h Apollo AGM (HZB12-100) has spec sheets indicating max charge voltage of 14.1 V. Fortunately, I have the Arrid model that puts out just that as a max.
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Follow Up By: Member - Ian W (NSW) - Wednesday, May 07, 2008 at 16:35

Wednesday, May 07, 2008 at 16:35
Following on from Robin Miller's post,

Sighting many recommendations on the Caravan Forum I purchased the Jaycar MB-3620. This is used to charge a 100 a.h. Wet Deep Cycle in our tent trailer. Whilst touring its connected to mains power on the odd occasions we pull into a caravan park, then if necessary, after checking with an amp metre I use my Honda Generator.

Am totally satisfied with the product and would suggest that it would be hard to beat from a value for money point of view.

Ian
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Follow Up By: Mike Harding - Thursday, May 08, 2008 at 07:57

Thursday, May 08, 2008 at 07:57
Hi Bushfix

14V1 is a pretty low maximum charging voltage for an AGM – I note Apollo no longer make batteries but simply import them from China so unless the data sheet you have is the original produced by the manufacturers it would be worth seeking confirmation of that number – not that it matters it will just take a bit longer to reach full charge.

Fullriver and Ritar, who have an enormous part of the consumer AGM battery market, specify 14V9 and 15V0 respectively for maximum charging voltages. Lifeline, which Jim mentions below, specify 14V4 so I think people can rest assured that a cyclic charging voltage of 14V4 will not cause their batteries to gas – it must, of course, be removed or reduced to float level once the battery is fully charged.

Mike Harding

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Reply By: Member - Roachie (SA) - Monday, May 05, 2008 at 19:49

Monday, May 05, 2008 at 19:49
Have alook here:
http://www.sidewinder.com.au/product5.html

I have one of those blue coloured (the 15 amp version) ones in my camper trailer and another one in the back of my Patrol.

You may also want to consider fitting one of these:
http://www.arrid.net.au/twin.html
These are great for supplying a 20 amp charge from the tow vehicle, without having to use really heavy cable.

Roachie
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Follow Up By: Member - barry F (NSW) - Monday, May 05, 2008 at 20:02

Monday, May 05, 2008 at 20:02
Thanks Roachie & Goldfind for your help. I will have to look up that info tomorrow as at the moment Iam getting"the look" from SHMBI. LOL.
Anyway at this stage my old faithfull Woolies unit looks like being retired, like I am about to be!! Cheers.
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Follow Up By: Member - Matt M (ACT) - Monday, May 05, 2008 at 20:10

Monday, May 05, 2008 at 20:10
SHMBI?

She Who Must Be Ignored?
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Follow Up By: Ianw - Monday, May 05, 2008 at 22:07

Monday, May 05, 2008 at 22:07
If you check out Derek (from sidewinder.com.au) on Ebay his 15 amp charger is available for only $149.50, not $195 as in his sidewinder.com.au site. I have just bought one and am in the process of testing it out.
Ian
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Follow Up By: Member - barry F (NSW) - Tuesday, May 06, 2008 at 06:48

Tuesday, May 06, 2008 at 06:48
Yes Matt, IGNORED is right. ( Until she tells me otherwise!!)
It's woosey Qld blokes who use the term OBEYED. LOL & cheers.
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Reply By: Mainey (wa) - Monday, May 05, 2008 at 20:21

Monday, May 05, 2008 at 20:21
Barry,
you say: ""We have *NO* means of charging the battery *UNLESS* we are on a 240v powered sight""


Do I understand you can ONLY recharge from 240v
.... and NOT from the Alternator while driving ??

Mainey . . .
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Follow Up By: Member - barry F (NSW) - Tuesday, May 06, 2008 at 06:55

Tuesday, May 06, 2008 at 06:55
Howdy Mainey, yes mate thats right. We mostly stay in caravan parks on powered sights when travelling or holidaying. We recently updated our van to one with an ensuite in it so intend to get a bit more use out of it by staying in national parks type areas etc close to home, but only for a couple of nights at a time. We only needed the batterey to run the lights & not much else. Cheers
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Follow Up By: Mainey (wa) - Tuesday, May 06, 2008 at 09:24

Tuesday, May 06, 2008 at 09:24
Barry, consider having the Aux battery charged while travelling, direct by the vehicle Alternator, as there are *NO* 240v charging facilities available in National parks.

How do you run a fridge when in the National park ??

Mainey . . .
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Follow Up By: Ircon - Tuesday, May 06, 2008 at 09:56

Tuesday, May 06, 2008 at 09:56
Absortion fridges can run on gas
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Follow Up By: Mainey (wa) - Tuesday, May 06, 2008 at 10:14

Tuesday, May 06, 2008 at 10:14
Ircon

unfortunately and definitely *N O T* when your driving !!

Mainey . . .
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Follow Up By: Ircon - Tuesday, May 06, 2008 at 10:28

Tuesday, May 06, 2008 at 10:28
Main,

Your question was:-

"How do you run a fridge when in the National park ??

I assume you didn't mean driving!
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Follow Up By: Mainey (wa) - Tuesday, May 06, 2008 at 11:01

Tuesday, May 06, 2008 at 11:01
Ircon,
yes your correct, I didn't mean when driving
I meant when camped in the National Parks, that's why I posted
""unfortunately and definitely *N O T* when your driving !!""

Hope that clears up any misunderstanding.

Mainey . . .
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Reply By: Best Off Road - Tuesday, May 06, 2008 at 07:24

Tuesday, May 06, 2008 at 07:24
Barry,

As advised above, get a 3 stage. Or to do it on the cheap, Projecta Charge Controller BM 140, is a device that you fit (easily) between your old charger and the battery. It is a two stage device that swings into float mode to stop overcharging occurring. I've had one for ages, works well. About $50.

Trickle chargers are bloody dangerous. They continue to put charge in when it is not needed. Think of it like a dripping tap into a bucket. Eventually the bucket fills and then overflows. Problem is with a battery, it can't overflow effectively.

Result is with conventional wet cell batts they boill dry, and AGM's simply expand and swell, rooting them. Chris at Battery World, Wantirna, has told me stories of having to smash cupboards in Winnebago's to get swollen AGM's out that have been "trickle" charged.

Jim.



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Follow Up By: Mainey (wa) - Tuesday, May 06, 2008 at 08:59

Tuesday, May 06, 2008 at 08:59
Jim,
were you writing this in your sleep:-> ""Trickle chargers are bloody dangerous. They continue to put charge in when it is not needed. Think of it like a dripping tap into a bucket. Eventually the bucket fills and then overflows. Problem is with a battery, it can't overflow effectively""
I don't agree, but you must be correct - because you make sliding timber stuff :-)) an I only **** batteries an solar equip, so would not have any detailed knowledge ?

Mainey . . .
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Follow Up By: Best Off Road - Tuesday, May 06, 2008 at 10:15

Tuesday, May 06, 2008 at 10:15
Mainey,

Firstly you need to observe your own catchline

"sure it’s nice to be important - however, it’s more important to be nice"

Now, the advice I passed on was based on what Chris told me. He is an expert in the field. I trust his opinion. If you've got a beef, ring him and abuse him.

Just for your information, I'm not just a thick cabinet maker. I'm tertiary educated, held various Senior Management positions with large organisations, and now in business for myself again. I "build sliding stuff" because I saw a business opportunity, evaluated it, invested a lot of money in it and no surprise to myself, it is a raging success.

Jim.

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Follow Up By: Mainey (wa) - Tuesday, May 06, 2008 at 11:57

Tuesday, May 06, 2008 at 11:57
Jim,
My humble and sincere apologies....
I never said you are ""just a THICK cabinet maker"" actually they are YOUR words.

You say Chris from Battery World Wantirna is an expert and has told you he believes 3 x stage battery chargers are dangerous, he has also given you the reasons too!!

I wonder why Battery World Wantirna would stock and sell electronic products they believe to be dangerous and also inefficient.
The Australian Standards committee should be informed!!

Reading the previous posts the very real benefits derived from 3 x stage battery chargers are clearly evident !!

I'm sure they (3 x stage battery chargers) would not be sold as 'recommended products' if they did not work as safely and efficiently as they actually do, unless they are cheap 'knock-offs' of genuine products of course, as we know anyone can attempt to copy the efficient designs of reputable electronic companies using cheaper components and then undercut the price slightly.

I wonder what is the most *efficient* type of battery charger . . .
if it's not the multi stage chargers ??

Mainey . . .
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Follow Up By: Best Off Road - Tuesday, May 06, 2008 at 17:07

Tuesday, May 06, 2008 at 17:07
I said get a three stage.

I did not say 3 stages are dangerous.

I said Trickle Chargers ARE dangerous.

Jim.



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Follow Up By: Nomadic Navara - Tuesday, May 06, 2008 at 17:15

Tuesday, May 06, 2008 at 17:15
Mainey

Why do you keep making a fool of yourself and taking the bull by the ar$e? Jim made no mention in his opening paragraph about three stage chargers being dangerous.

However in his second paragraph he turned his attention to trickle chargers, Barry in his first posting said he has one and that he was thinking of using it. Jim went on to instruct him as to why he should not. Jim is perfectly correct in what he said.

Trickle chargers do not have any regulation apart from a transformer with poor regulation. They are not capable of putting out much current. When the battery becomes near full charge the output does not taper off like it does in a multi stage charger. Jim gave a good laymans explanation of what happens. Learn from him.

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Follow Up By: Mainey (wa) - Tuesday, May 06, 2008 at 19:31

Tuesday, May 06, 2008 at 19:31
The Ctek charger has various charging stages, from "bulk" through to "Absorption" and also a "maintenance" charging program, enabling the Ctek charger to remain connected to the battery, running what Ctek call their "maintenance" charging system safely, they nominate it's safe to remain connected for many months at a time.

So what's the technical difference between the Ctek "Maintenance" program and a "trickle" charge program from some other quality manufacturers and the $50 "Projecta Charge Controller BM 140" running in "float" mode ?

Can we name just one "trickle charge battery charger" that is known to be "dangerous" when used as the manufacturer recomends ??

Mainey . . .
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Follow Up By: Best Off Road - Tuesday, May 06, 2008 at 21:10

Tuesday, May 06, 2008 at 21:10
I suggest you see your Doctor Mainey.

I mean it sincerely, you are waffling about stuff that was never raised.

Jim.

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Follow Up By: Mainey (wa) - Tuesday, May 06, 2008 at 21:31

Tuesday, May 06, 2008 at 21:31
But Jim, I did ask you to name just one 'trickle charge battery charger' that you said are 'dangerous' products
and you start childish name calling

is it really just to avoid the direct question asked of you ?

Would the doc know the battery charger brand LOL

Mainey . . .
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Follow Up By: Nomadic Navara - Tuesday, May 06, 2008 at 23:45

Tuesday, May 06, 2008 at 23:45
Mainey

You just introduced another variable "that is known to be "dangerous when used as the manufacturer recomends" - The manufacturer recommends that they be connected only to charge the battery and then switched off. Despite this, many leave them on thinking they will trickle charge just like the multi stage chargers do. From the original message it looked like Barry was going to run his cheap trickle charger while he was camped to maintain his battery. Jim was explaining that this was not a good idea. Next thing you will be telling us guns are not dangerous when used indiscriminately.

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Follow Up By: Mainey (wa) - Wednesday, May 07, 2008 at 00:06

Wednesday, May 07, 2008 at 00:06
Peter
In this case the manufacturer DOES actually state their Battery Charger can in fact be left connected to the battery for MANY months.

The following Ctek link CLEARLY states their battery chargers can be left connected for many MONTHS at a time.

This is NOT just my idea, it's the manufactures statement of confidence in their own product.

Link: The Ctek charger can be connected for months, ideal for seasonal vehicles

-Guns are not dangerous - it's the user that's dangerous-

Mainey . . .

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Follow Up By: Nomadic Navara - Wednesday, May 07, 2008 at 00:26

Wednesday, May 07, 2008 at 00:26
Mainey

Where did Jim say Ctek chargers (or for that matter any good multi stage charger) was dangerous to leave connected to a battery? In his opening paragraph he advocated installing a 3 stage charger.

Can't you get it into your thick head that the next 2 paragraphs were condemning the cheap chain store trickle charger that Barry had originally intended to use.

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Follow Up By: Mainey (wa) - Wednesday, May 07, 2008 at 08:33

Wednesday, May 07, 2008 at 08:33
Peter,
Jim posted: "Trickle chargers are bloody dangerous. They continue to put charge in when it is not needed. Think of it like a dripping tap into a bucket. Eventually the bucket fills and then overflows. Problem is with a battery, it can't overflow effectively. Result is with conventional wet cell batts they boill dry, and AGM's simply expand and swell, rooting them"

As I have asked, can you name just one "Trickle charger" that is "dangerous" when used as the manufacturer states, and will boill dry wet cell batts and expand AGM's to the point of making them useless.

Mainey . . .
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Follow Up By: Best Off Road - Wednesday, May 07, 2008 at 09:58

Wednesday, May 07, 2008 at 09:58
Barry asked in his original question

"We have no means of charging the battery unless we are on a 240v powered sight. My intention was to use a "trickle" charger that i bought from woolies about 25 - 30 years ago!!"

I'll bet my left one that charger is dangerous by my defintion.

Jim.

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Follow Up By: Member - Phil G (SA) - Wednesday, May 07, 2008 at 12:44

Wednesday, May 07, 2008 at 12:44
Sheeshe, I'll wade in......

If Jim changed his statement to "Cheap, UNREGULATED chargers" instead of "trickle chargers" then we'd save about 12 posts.

Your mate Chris would be referring to the old Arlec style which is unregulated - can put out 15-16V so will trach a battery if left on, despite its low output. It is not atrickle charger. "Trickle chargers" are REGULATED at 13.8V, which will not trash a battery.
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Follow Up By: Best Off Road - Wednesday, May 07, 2008 at 14:43

Wednesday, May 07, 2008 at 14:43
This sort of rot is the very reason Collyn Rivers left this site.

You offer up a bit of technically sound, commonsense and evryone who thinks they are an expert come along a have a free hit.

Phil, you are VERY wrong. 13.8 volts WILL continue to charge any battery, albeit slowly, and eventually destroy it. That is why 3 stage chargers have a float setting switch on them for Wet Cells and AGM/Gel. These put out 13.1 or 13.2 for AGM/Gel and 13.4 for wet cell.

And just out of interest I looked at the top of my Lifeline AGM (top quality AGM) and it quotes a float range of 13.2 to 13.4. Trickle charge one of these at 13.8 and it will swell until it splits its case.

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Follow Up By: Member - Phil G (SA) - Wednesday, May 07, 2008 at 20:12

Wednesday, May 07, 2008 at 20:12
Gday Jim,
If I am "very WRONG" perhaps you can kindly give me the answers to the following:

Why do many AGM batteries specify a float voltage of 13.5-13.8V?

Why do most multistage chargers (including the ones mentioned on this thread - CTek, Sidewinder and Jaycar) float at 13.8?

Can you name a multistage charger that floats at 13.1-13.2V?

Can you tell me your source of info for AGMs swelling and splitting case at 13.8V?

I do my homework before posting. I agree with you about Collyn - great shame.
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Follow Up By: Nomadic Navara - Thursday, May 08, 2008 at 00:54

Thursday, May 08, 2008 at 00:54
Phil

"Can you tell me your source of info for AGMs swelling and splitting case at 13.8V?"

The cheap trickle chargers that Jim was referring to are not regulated to 13.8 V.

It seems some on this forum are having some difficulty with terminology. Multi stage chargers do not "trickle charge" they float charge. Float charging if set to the correct voltage is no danger to any battery. The dangerous chargers are the trickle chargers, They have an open circuit of 15 to 18 V and the current regulation of them comes from the design of the transformer. When left connected to a battery as you would if this was your power source in a van park they will overcharge your battery. Any constant charger has to be monitored and disconnected when the battery has received sufficient charge and these trickle chargers are nearly are a constant current device.

PeterD
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Follow Up By: Nifty1 - Thursday, May 08, 2008 at 09:04

Thursday, May 08, 2008 at 09:04
Sorry to break up this sub-thread, but just wanted to make a comment on the Projecta Charge Controller, Jim. I had one of these and it was a disaster - overcharged a very expensive Trojan. I got my money back and bought a Jaycar 3620 which is fine. I'm a bit sour on anything with Projecta brand now.

OK, you can all get back to your arguments now...
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Follow Up By: ajr - Monday, May 19, 2008 at 14:38

Monday, May 19, 2008 at 14:38
phil,
there is a 3 stage charger that operates from your VEHICLE battery and has adjustable voltages and current that can be set by you to suit any battery. a bit expensive maybe but you will only buy once and be happy.

have a look at www.ranox.com.au

ajr
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Reply By: Ircon - Tuesday, May 06, 2008 at 09:38

Tuesday, May 06, 2008 at 09:38
Hi Barry,

I have been looking at all the issues of dual batteries in the tow vehicle, and batteries in the caravan for quite some time now. I am about to pick up my new caravan and like you we are looking at a mixture of free camping and caravan parks.
I think I am now at the stage of knowing what I don't know, which I think is healthy.
If the van does not already have it, my recommendation would be to install a CTEK or equivalent "smart" charger either a 7 A or 25 A version depending on your budget. I happily got away with a 7A version in my last van but we did very little camping where there was no power.
Bainbridge Technologies are the Australian agents:-

http://www.bainbridgetechnologies.com/index.php?page=catalogue&cid=63&local=yes

The CTEK charges also have a "supply" mode but can be left on "float" indefinately.

Now charging the van battery when you don't have access to 240 V ac is a whole different matter.
Three normal methods (or combination of all)
Solar with quality regulator
Generator
Tow vehicle alternator
The first two have the capability to fully charge your battery. The third, under most circumstances can't.
At the moment I am researching the best way to maximise charging the battery in the caravan from the vehicle's alterantor and looking at battery to battery bosters/smart chargers such as made by RANOX and Sterling.
So far, by actual practical testing, I have found that my vehicle's alternator puts out about 14.2 V DC when first started and the engine is cold. After about 20 minutes or so of driving the output drops to 13.69 V DC. This I a believe is due to temperature compensation in the alternator to prevent overcharging/damaging the cranking battery.
There has been much debate about this, but I can only report as to what ACTUALLY happens with MY car.
My conclusion is that at 13.69 V DC at the alternator you will never adequately charge the caravan battery even if you have zero resistance in the cables that runs from the car to the caravan battery.
If you use a simple batterry to battery booster that does not incorporate a smart charger you run the risk of damaging the caravan battery from over charging.

As far as I can tell the same is true of any auxiliary battery installed under the bonnet.

These are my thoughts/findings only. I am by no means an expert and these comments may be challenged by others but that is the beauty of forums such as this

Regards,

Rosscoe

AnswerID: 302287

Follow Up By: Mainey (wa) - Tuesday, May 06, 2008 at 12:12

Tuesday, May 06, 2008 at 12:12
Rosco,
if there is more current produced, and actually reach's the (+) battery terminal - than is stored with-in the battery, the battery will charge !!

Mainey . .
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FollowupID: 568352

Follow Up By: Ircon - Tuesday, May 06, 2008 at 12:31

Tuesday, May 06, 2008 at 12:31
Mainey,

But as far as I can tell, at 10 sq mm cable, the time taken while driving is a practical limitation and while some recharging will occur, I would have thought, above 80% cannot be realistically expected.
Therefore the old problem. 100 Ah battery. Charged to 80% and only discharged to 50% (to prevent premature battery failure) results in only 30 Ah of usable power.
So you leave home with a fully charged battery and the first camp you have 50 Ah and from then on only 30 Ah (max) until you charge the batteries by other than the vehicles alternator.
AND I think the auxiliary battery under the bonnet that powers your compressor car fridge suffers the same problem.

Rosscoe
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FollowupID: 568353

Follow Up By: Member - barry F (NSW) - Tuesday, May 06, 2008 at 17:08

Tuesday, May 06, 2008 at 17:08
Thanks everyone for your advise. I will sort though it in the next day or so and buy a charger that will suit our battery type & our particular needs.
It was a great response & your input must appreciated. Cheers.
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FollowupID: 568386

Reply By: Nomadic Navara - Tuesday, May 06, 2008 at 17:29

Tuesday, May 06, 2008 at 17:29
Barry

You said your van was wired for a battery system. What is your van? Is it a Jayco? If so it has a power supply to power the 12 V lights. Some people in the dealer organisation claim this power supply is also a battery charger. Some also call it a "transformer" which it is certainly not, that shows up the poor level of electrical knowledge in the caravan industry. If you have a Jayco it is good to see that you are prepared to swap the Setec for a proper battery charger.

PeterD
PeterD
Retired radio and electronics technician

Lifetime Member
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AnswerID: 302366

Reply By: Mainey (wa) - Sunday, May 11, 2008 at 10:36

Sunday, May 11, 2008 at 10:36
Barry posted, "" what I realy need to know is :-> what sort of 240 volt plug in charger should I have to charge such a battery to *max efficiency* ? ""

He's not asking for the correct charging terminology of various types of battery chargers, he just wants to plug in a battery charger and forget it for a few days while it does it's thing when (and while) he's camped and has access to 240 Volt power.

Yes, the 12v battery will be in use, so it has to remain on charge and will continue to be charged (as required) simply because it's being used by the electrical appliances attached to it.

(the battery won't discharge because the 2 (or 3) stage charger will "maintain" it fully charged, or is that supposed to be 'trickle' charged or maybe I should simply use the terminology 'just getting a lick' of current, yes political correctness gone totally haywire, grrr)

Said very simply, in an automatic 2 (or 3 or even 6) stage battery charger the 12v battery *initially* gets charged (@ 14 PLUS Volts) then when this is achieved the voltage is *finally* reduced to 12.6v - 12.8v or thereabouts, and the current is reduced to just a 'trickle' (as in very very very small) just to maintain the battery in a fully charged state, if the battery is damaged when being charged in this way, it's because the battery charger is faulty - not the battery
(unless it's a battery with an inherent fault to start with)

Mainey . . .
AnswerID: 303204

Reply By: ajr - Monday, May 26, 2008 at 09:35

Monday, May 26, 2008 at 09:35
gentlemen,

when we talk 100% battery charge, we are asking something that most battery chargers will not give. most chargers are set to very safe default voltages that will suit a range of batteries and not damage them (or fully charge them). eg a boost voltage of 14.2 will suit some batteries but 14.5 may suit your particular style. Now, try and find a charger that will allow you to select voltages for a variety of batteries. if you can then be ready to take out a second mortgage.
Another huge overlooked area that is never found in "average or cheap" chargers is battery temperature compensation. how many people have commented to you at the campsite that you can never fully charge acold battery. This is because a cold battery requires a higher charge voltage (as a warm one needs a lower voltage). As you can imagine, the charge voltage required in Tasmania in winter is completely different to that in summer at Cairns, so the default is set to the LOWER voltage.
How many chargers have temperature compensation?. Certainly none from the cheaper outlets.
Under cold conditions and without the optimum charge voltage you may not reach 80% from a "average" 3 stage charger
What I am getting at is if you are chasing that 100% (or close to it) you need a charger that will suit your battery (AGM, SLA, flooded etc) or be adjustable, and including battery temperature compensation. If the salesman says NOT needed, then you will be settling for less than your batteries capacity. Unfortunately chargers of "integrity" will cost, but so do those batteries you carry and rely on.
AnswerID: 305889

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