CTEK vs REDARC

Thanks for that, great review, As Redarc is Aussie made, thats made my mind up,

cheers

HI Brenden
Sone other questions

[a]How is the battery charged at present?:
[b]From the vehicle alternator?
[c]IF so, by a direct connection from the vehicle battery?
IF[ 'b] & [c] does it CHARGE sucessfully ??
IF it does YOU HAVE NO NEED for a DC/dc charger such as the REDARC OR the Cetek DC/ DC charger

PeterQ

Hi Peter,
The only way the battery charges now is thru one of those 50amp plugs from the car when the trailer is connected. I want to be able to sit that camper trailer say in a caravan park with the 15a lead that will keep the battery charged to run everything like fridge and lights while parked so I do not have to connect to the car to charge the battery. Hope that makes sense?
Brenden

HI Brenden
Just a word of caution .
Some people get carried away with the need for DC /Dc chargers!!

If your trailer battery is satifactorily charged from the vehicle alternator ,when driving, you may have little neeed for a Dc/DC charger
The charge abilty of the direct connection will depend on TWO factors :
[a]The alternator peak voltage that it charges the CRANK battery to
[b]the Size of the cables to the trailer battery with regard to CABLE RUN LENGTH
I do hope you have some form of Automatic isolation between the car & trailer battery ??

A multi stage MAINS charger could well be ALL you need.
But please confirm the ACTUAL battery TYPE you are using
A MAINSs charger would not need to be anything like the 40A some suggest for a Dc /Dc charger
It should be just large enough to supply your max Current being used plus about 10A for 110Ahr LEAD ACID battery
Note: A bigger charger does not necessarily mean the battery can use ALL that Amps
The accetpance capacity of the battery at the CHARGER's boost voltage determines the max current the battery can draw

PeterQ

Hello
I maybe unpopular but I would go a Projecta.
You can select what battery type and it will automatically do the charging for you.or it can be a 12 volt supply.
I just purchased the 2500.its 25 amps.i have a calcium battery 170ah .the charger has a 7stage cycle to keep the batty in. Perfect condition.
Even if yo u have a lead acid you can use the projecta charger.
They are standard figment on coramal caravans now.
Mine comes with a remote to control and monitor battery condition and charging.
Purchased from good old eBay.


Dennis

"The faster you put it back in the longer the battery will last provided you use a multi stage chager of course such as a redarc or ctek. "

Not necessarily, I'm afraid.

Generally, the SOONER you recharge a battery the longer it will last in calendar terms. That does not necesarily mean that you should hit it with a charger with the highest output you can afford, even if it is multi stage.

Many, but not all, deep cycle and dual purpose lead-acid batteries, have a specified bulk charging rate of 10 to 15% of their C20 Ah capacity. So a 100Ah battery might be best charged at an initial rate of 10 to 15 amps.

Additionally the OP said he had a lead-free battery, so we don't know what the chemistry is and what the charging regime should be. Until we know that we are all shooting in the dark.

Cheers

It depends on the quality of the battery.
If you have a low resistance battery you can charge it at a much higher rate
My 150 ah battery can be charged at 200 amps or more.

HI Dennis
Perhaps NAME the battery??

PeterQ

Yeap agree, slower the charge the better BUT seeing we don't live in the ideal world charging batteries is a compromise just as the application we use the batteries for.

Getting back to the ideal world; a battery should never be discharged more than 5% as in standby power systems where batteries last 20 years..... in critical care applications it's 10 years before replacing.

Every time you discharge a battery your shortening the life expectancy, a battery 1/4 discharged will last longer than a battery thats been 1/2 discharged regularly all its life.

Hi Old Fellas.
Knowledgeable gents like yourselves should be aware of the capabilities of these low resistance batteries – ie Lifeline and Optima, to name a couple - but there are others.
I have an 150 amp hour Lifeline battery which I regularly charge at 100 amps, when repetitive deep cycling, (I would go higher but I’m limited by my charging equipment).
I quote from Lifeline’s Technical Document No. 6-0101
“The charging current during the Bulk stage should be set as high as practical; higher current levels mean faster recharge time. For repetitive deep cycling, chargers should have an output current of at least 0.2C (20 Amps for a 100 Ah battery). If the output current is less than this value, the cycle life of the battery may be negatively affected. Due to the low impedance design, Lifeline® batteries can tolerate in-rush current levels as high as 5C (500A for a 100Ah battery).”

Your quite right Dennis, any batter can be charged at very high currents but you have to maintained a maximum battery temp of 25 degrees C...... Even Lifeline and it is referred to in their charging specs.

As temperature increases charge rates decrease for a very good reason.

No matter what battery you have you can not change how chemistry works often referred to physical law or scientific law....... A battery is a big science chemistry set and nothing else.

In an automotive application maintaining a set charge temp can be very difficult especially under a bonnet or in the back of a 4x4 and can become worse with heat soak.

Over 12 months ago you did a similar post. 98620

I am not doubting how good Lifeline are ( They are a premium product) or what they say but there is some things in life that can't be altered. Marketing hype wins in the war of getting customers to by a said product. If you read all battery specs they will say the same thing, some advertise it and others don't .

It's like a tyre company advertising our tyres only require small amounts of weight to be added to become perfectly balanced .... When in fact nearly all tyres only need a small amount of weight to be perfectly balanced....... Those who get in first wins.

People need to look through the smoke hazed hype on a product before making an sensible choice.

Dennis, you need to post the whole paragraph when quoting.....

There was two lines you missed out and the most important part when using high charge rates.

“The time to reach full charge at temperatures in the range of 68 to 86°F (20-30°C) can be estimated from the following equation:"

Hi Olcoolone.
You quoted “you need to post the whole paragraph when quoting”
The document is many pages long – I included the document number for reference.

You quoted “max battery temp of 25 degrees”
If that was the case I wouldn’t be able to use it – I camp in ambient temperatures of up to 40 degrees - Lifeline quote a max operating temp of 71 degrees.

I have a temperature probe fitted to the battery and it’s temperature rise is about, 5 degrees at a charge rate of 100 amps from 50 precent DOD (hardly thermal runaway).
Lifeline quote “As of this writing, Concorde does not know of any Lifeline® AGM batteries that have failed due to thermal runaway.”

When I am running the caravan on batteries, this is high charge rate is applied a least once a day.
It’s the batteries low internal resistance that keeps its temperature low – my charging regime would destroy a standard AGM on its first charge.

Just stating fact.

I’ll stick to the manufacturer’s specifications – they will do me as facts in preference to your facts.

HI
Yes ,Dennis
Low internal resistance does mean less heat generated within the battery
Low internal resistance also means higher charge currents for the SAME applied voltage.

You would be aware of it , but for the benifit of others, THAT means they will need to consider the MAX continious CURRENT rating of the charging source ,[ battery charger, dc /dc charger , unless they have overtemp protection ,] and vehicle alternator .

Some unpleasent surprises with another low impedance battery [LiPo Fe] when that was not recognised.


PeterQ

Hi Oldtrack - I have 5 battery chargers, a DC/DC charger, and an inverter all are electronically current limited and over temperature protected. Never struck one yet that didn’t have these protections – wouldn’t buy them otherwise.

HI Dennis
Yes most are ,but what about the ALTERNATOR
PeterQ

Hi Oldtrack,
When stationary - I use the 240V/100 amp charger off my 2.4 kva Yamaha genset.
When moving – the Toyota Troopy’s 150 amp alternator charges the 150 AH Lifeline ok – I haven’t measured its charge rate – but never had a problem.

HI Dennis
NOW THAT does give the necessary details , for OTHERS to understand what is possibly needed with low impedance batterries.
I think you would agree ,everyone do not have 150A altrnators

So to those considering going to fast charge rate, low impedance batteries , CHECK your charging sources ratings!!!
for instance a 60A alternator would not take kindly to trying to pump out 100A for more than a few minutes

There is a degree of self limiting in alternators but THEY DO /CAN BURN OUT DUE TO OVERLOAD
PeterQ

When talking about spec, 25 Deg C is what is stated as a reference. Of course they will comfortable handle temps up to 60 deg C.... So many be a better understand What the post was referring to before any "oh pleases".

you said
"Your quite right Dennis, any batter can be charged at very high currents but you have to maintained a maximum battery temp of 25 degrees C...... Even Lifeline and it is referred to in their charging specs."

Sorry far from accurate or helpfull.

if you read many of the battery specs..and understand....they have corrected charge voltages for a range of temperatures.

Some batteries will have current limits and those limits may be corrected for temperature.

most likely the current limits will remain but the charge voltages will be varied against temp..so that the currents remain within limits.

This is nothing to do with a maximum battery temperature of 25C.

in the preceeding post you said,

"Of course they will comfortable handle temps up to 60 deg C.... "

sorry this is also inaccurate and unhelpfull.

Almost any lead acid battery will be very unhappy at 60C, that is hot eunough to burn soft skin on contact.
Any battery I found at those sorts of temps I would be taking a couple of calm steps away from, until it proved not to be dangerous and overheated for a reason..

In fact many AGM batteries we find on the market are beyond their specified operating temps at 45 C, 60 C would certainly put many batteries outside their specified storage temps.

This is why we find a lot of AGM performing exceedingly badly in under bonnet situations.
Some of these AGMs being sold into the camping, 4wd and caravan market are unsuitable for use in summer in the shade in free air in some areas.

Some of the battery specs will quote fairly wide operating temps in their general ststements on one hand, but when you get further into the specifics, that is not the whole truth.
Outside a far narrower temp range the performance ( every single parameter) and life of the battery declines dramatically....very dramatically in some cases.

In this day and age, almost all generalisations concerning batteries can be found to be unreliable.

because there have been so many variations in the battery technology come to market we MUST consult the manufacturers specifications......when I say manufacturer I mean just that because some badge engineered battery resellers are slap happy with their claims.

cheers