DC to DC Chargers

[Glen and Debbie]

Hi all,

Has anyone fitted a DC to DC charger and what benefits have you noticed? Also, what's the best method of hooking them up and what, if any, problems have you encountered? :confused1:

The reason I'm asking is that I often find that the van batteries aren't at their peak charge after driving for some distance. I believe this is being limited by the regulated power supply from the car via the Anderson plug.

If you've got a system that works, I'd like to hear about it. :helpsmilie:

[TonyH]

Hi Glen,

DC to DC????

I have & know of AC to DC chargers.

When travelling I believe that the tow vehicle will be charging the (van) batteries via the anderson plug, also if there is sufficent sun you should be getting charge through the solar panels.

One of the first things I do when setting up for the night when getting in the van is to check the battery voltage, usually showing 13.5 to 13.8v which I consider to be pretty well spot on.

You dont mention what your reading is.

I would consider putting a multi meter across your car battery & checking your alternator output & seeing if it is up to scratch.

I hope you get to the 'bottom' of this as you must have the fridge working to keep the beer cold! :laugh:

CU down the road

[Glen and Debbie]

Thanks Tony,

I'm actually refering to the DC to DC chargers like the one made by Redarc. I have since found that Springers have them and their Lawnton store is located close to home, so I will see what they have to say.

My voltages are usually the same as yours, but sometimes less. I was basically trying to find out if there are any advantages to having one, such as better battery maintenance or are they a waste of money with the set ups we have with Anderson plug and solar power.

I've just bought a LC200 so I'll see how it goes when we go to Milmerran.

[Rod and Mavis]

Greetings all

We have had a “REDARC” DC to DC charger fitted for the last 5 months.

This little beasty is a 25 amp smart charger.

The reason I went for this extra expense was the fact that our AGM fridge battery in the car only lasted for under 3 years.

That is pretty good you might say but I was not impressed as our 3 house batteries in the van have just ticked over 5 years in operation and still going strong (touch wood). This is due I firmly believe to the way that they are kept correctly charged by the solar and the smart (240v) charger and probably also due to the fact that we had the van was re wired correctly soon after we took delivery.

The REDARC not only looks after the aux battery in the car and the van house batteries from the alternator but also uses the caravan charging systems (solar and 240v charger) when the car is plugged in via the Anderson plug and car engine not running.

Lotta money but all indications are that it should do the job and it is nice to have visual confirmation that all is well. :thumbsup:

[reece]

Hi

Ihave just ordered a TP but currently have a prado pulling a Kimberley Kamper and from the Anderson plug you can only produce 12.8 v and you need 13v + to charge the batteries in the camper while travelling, the whole thing is a pain as i have no solar panels. I looked into the Redarc fix and if i was going to keep the camper i would do it. I f you do decide make sure you get the Redarc as close to the batteries as you can.

Regards

Reece

[Rod and Mavis]

Hi Reece.

If your wiring is adequate you will get full voltage with very minimal drop.

Bigger is better with 12 volt systems. The lower the voltage the larger the wire needed!

[John and Ann]

Hi all,

Generally the principle of bigger is better for DC wiring is correct, however, when it comes to your vehicle and RV battery system, not all batteries are equal.

Things that might be considered when looking at the RV battery system charging and maintenance are:

1. Vehicle batteries are generally WET (Lead Acid), for cranking power.
   
2. RV batteries as supplied by Kedron are probably AGM, for deep cycle use.
   
3. Batteries of different chemistry WET, AGM, GEL and the like require a different charge voltage for optimal charging.
   
4. Batteries of different chemistry should not as a rule be grouped due to their specific charge cycle needs.
   
5. Charge voltage applied by the regulator is determined by the average voltage state of the battery group, not the individual state of any one battery.
   
6. Charging your RV batteries via the Anderson plug groups your RV batteries with the vehicle batteries, therefore, potentially grouping batteries of dissimilar chemistry.
   
7. Charging your RV batteries via the Anderson plug unless done via a DC-DC charger may be at the expense of optimal charge of you vehicle batteries. As an example, most vehicle dual battery systems will not start charging your auxiliary battery until your engine battery(s) has reached a pre-determined state of charge. Think of the RV battery group as an auxiliary battery for the vehicle.
   
8. As a general rule if a battery in a battery group needs to be relaced than all should be replaced at the same time.
   

When looking at our vehicle and RV DC charging I will likely use the REDARC unit, but there are others about.

All the best :thumbsup:

[Glen and Debbie]

Hi again,

Here's another spin on how to charge things. I went and spoke to Joe Springer and his advice is as follows. I should add that this advice was in relation to my set up and my needs at the time.

I have 3 batteries and 500 watts of solar panels with a 30 amp regulator on the van. I have a 40 amp charger and 800 watt inverter also.

He believes the Redarc would be a waste of money in my situation ($495.00 for the unit alone). The problem is the Redarc only puts out 25 amps, so if your batteries are down when you start driving it will take many hours of driving to bring them back up again.

Stage 1: What he suggests for me is a 140 amp solenoid with very heavy cabling running to a 125 AH AGM battery (which I will locate in the rear compartment next to the fridge). He will then continue this heavy cabling to the rear bar with a larger Anderson plug fitted. This will provide 70 amps of charge from the alternator (once the cranking batteries are charged) booting up the battery much quicker. This part including the battery is costing me $1050.00. He didn't indicate any problem with different batteries.

Stage 2: For the van he will replace the the Anderson plug and cabling and run it to the inverter via a switch (Can fit a auto switch for $400 extra). This will then power the 40 amp charger and charge the batteries much quicker. He is yet to work out the switching and circuitry for this so a price is yet to come. Other things to be considered, like charging the car fridge battery from solar power when parked will have to be incorporated also. But I'm sure he can work it out somehow.

ARB and TJM have 2 options. One is to install a 3rd battery under the bonnet, but you can only fit a 55 amp one via a solenoid for around $1400.00. The second option is to replace both starting batteries with larger ones. One a deep cycle and the other cranking separated by a solenoid. This voids all warranties and costs around $1500.00.

Anyhow I'm going with Springers stage one for now. Fingers crossed and thanks for your comments so far.

[Webby]

Hi Glen & Debbie,

Sounds very similar to the setup that Joe Springer installed for us before we left on our trip. We are more than happy with the charging and felt it was well worth the dollars spent. I was a little sceptical at first, but I am now one of the converted. It has made significant differences to our charging.

I believe a handful of other KOGGERS have had the same setup from Springers and from what I hear they are happy with their setups as well.

[Glen and Debbie]

Hi Sue,

You both must feel like locals by now in WA.

Glad to hear positive comments about this set up as it's allways a bit daunting spending dollars on something you're not familiar with. :thumbsup:

[Steve and Kez]

Hello all,

I am not exactly sure if this bit of info is suitable but I will put it out there just in case.

While I haven't had anything to do with inverters or caravans as yet (ours is on order), I do have a camper and I run 4 batteries in total.

1 for starting, a second under the bonnet for the winch and fridge in veh and 2 for the camper.

I run a "Rotronics" system which is a battery managment system.

Basiclly it takes control of the output from the alternator and directs it to the various batteries. It gives "full" charge to all the batteries via a computer managment system unlike 99.9% of other duel battery systems which only trickle charge the extra batteries.

It is an "off the shelf" product and is extremly robust as we are avide 4X4 drivers.

The owner of the company will not deal with most of the 4x4 accessary places like ARB & TJM. He seems to deal with the independant stores however I purchased mine through Opposite Lock.

The system is very impressive and I have been using it now for 11 years with out any faults.

I hope this is helpful

[Glen and Debbie]

Hi Steve & Kez,

I know the system you are talking about as I had the same on my 100 series. The purpose of the Redarc system is to charge the deep cycle batteries in the way that suits them, which is slightly different to the lead acid type used for starting or winching. If the batteries are charged correctly they will last much longer. Some people are having problems with deep cycle batteries due to being linked to the lead acid batteries, often via a solenoid. Springers also recommend locating deep cycle batteries out of the engine bay as the heat effects them.

Back to Stage 1 & 2 of my previous plan. After taking into consideration all of my needs for the battery set up including charging from the solar panels while still plugged in via Anderson plug, Joe Springer decided it was going to be far to complicated, requiring relays, switches etc....

So he now recommends Stage one (which is what Rod & Sue have according to Joe Springer) and that's heavy cabling from the solenoid in the engine bay right through to the van batteries. This will provide a rapid charge of approximately 70 amps with the solar backing it up as well.

To better look after my auxiliary battery in the back of the car he suggests the Redarc unit as it can provide 25 amps of charge which is adequate for one battery. The question is do I spend almost $500.00 for one of these to try and get an extra year or so out of one battery? :confused:

[John and Ann]

Hi Glen,

FYI Sidewinder have a similar unit to Redarc which caters for different battery (chemistries) types and is rated at 30A charge http://www.sidewinder.com.au/page168aa.html, the price is a more affordable $249.95.

[Winnecke]

Hi Glen and Debbie, I haven't researched the Redarc as I had already installed a Ranox http://www.ranox.com.au/ . This would appear to have the same purpose as the Redarc, and I have found it to be an exceptionally effective unit which can be used not only to keep your auxillary battery fully charged, but to "bring home" surplus charge which can be transferred to your van when you have a standing camp. It can be user programmed within a number of parameters, and the current price is $465 delivered. Contact (either) Alan and they will email you a user manual, or you can download one from http://www.vehiclemods.net.au/docs/RanOx_M...am_Rev_4H1m.pdf

I installed my Ranox in conjunction with (on top of) a National Luna Power pack http://www.nationalluna.com/PPPack.htm containing a 120 amp AGM battery in the back of my LC200. The National Luna line can be obtained through Opposite Lock rebadged as Chargemaster. I forget what I paid but found a listing at http://www.oppositelock.com.au/index.php?n...category_id=607 for $698. This also allows input or output via various plugs. I hook an 80 amp Solar Panel via the inbuilt Anderson plug to keep the fridge working hard when the fish are biting

[Glen and Debbie]

Thanks guys,

There's obviously quite a few options out there, so I'll check the sites out you've sent and hopefully make an informed decision at some point. :thumbsup:

[Alan and Jayne]

G'day

I was wondering if anyone can give me some specifics on the preformance of DC to DC chargers on Kedron vans.

We get around 13amps max via our Anderson plug to the van now, this is without any extra equipment. However when we're camped in National Parks where generators are not allowed, & usually they have lots of shade, this isn't really an option to charge the Kedron.

Therefore my question is, with a 30 amp DC to DC charger & no other special wiring, what madnitude of amps can I expect with this charger connected to the Anderson Plug that's on the Kedron. will it be 30A or close to it?

I'm looking for someone with actual experience with such a setup.

Can anyone assist?

Cheers

Alan

[Rod and Mavis]

Hi Alan & Jane.

Fitting a very expensive charger will probably not help.

If you are only getting 13 amps from the car now your wiring is not adequate and fitting a DC to DC charger will still only push in what the wiring will allow.

Most of what you want to go to the batteries is now lost as heat and with out doubt will not be the 30 amps produced by the charger.

Remember the lower the voltage the bigger the wiring has to be.

Our rigs (car & Van )Anderson charge lead has 25 sq mm wire and the large plug.

With batteries depleted in the van it is not uncommon to see 50 amps flowing to the van from the car.

I would suggest a chat to a GOOD 12 volt specialist before you spend on the charger.

Cheers and hope this helps.

[Alan and Jayne]

G'day Rod

Thanks for your input. From what I've read here a re-wire will cost around $1200 whereas a 30amp DC to DC charger is currently $250.

So before I dive in for a re-wire I was hoping to hear from someone who has actually tried a DC to DC charger on a Kedron.

Cheers

Alan

[John and Ann]

Hi Alan,

I have installed a Rederac BCDC1220 in my car to charge the dual 100ah AGM batteries in the rear and a BCDC1240 in our van to charge the three 120ah batteries there. They work a treat and have distinct advantages over simply parralelling up you car and van via the Anderson without any other intervening devices.

For a start the AGM's in your van have a different optimal charge voltage which can only be achieved using a DCDC charger. The Redarc units switch on automatically they sense the car alternator is online. If there is volt drop due to wiring lengths the DCDC charger maintains optimal charges voltage regardless but within reason.

It is not necessary to install 25mn2 cable, although I have in my car at least because I have multiple systems and a 90ltr fridge hanging off it via a number of circuit breakers in the rear of the car. I would suggest a min of 10mm2 cable to the Anderson plug of your car.

Simple parralelling is I believe a hangover from the days when your car batteries were of the same chemistry as you would have in your van, that is no longer the case. So my belief is the optimal solution for best long term benefit is DCDC charging.

Remember that if you do opt to just go with upgrading wiring to minimize volt drop and don't install any intervening devices then you have the potential to drag your vehicles batteries down with those in your van should you leave the Anderson charge plug connected.

That's my view anyway, it's cheaper and a simple DIY job.

Ask away if you have any other questions.

John

[Alan and Jayne]

G'day John

What. A brilliant reply. Thanks! You made a lot of sense & I really appreciate your input.

Where do you have your DCDC charger mounted? I think it would be in the car as you charge the fridge in your back end & I guess somewhere between your battery & the standard Anderson plug on your car?

We don't normally have a power issue, even when towing & always arrive with charged batteries. But when we are at a standing camp in a National Park that doesn't allow generators & there's no sun, we obviously need a solution. This is a fairly unusual set of conditions, so I didn't want to throw too much at a solution. 99% of the time we're ok.

As we are underway on our 8 month tour of this fine land, I won't be at a place to have any fancy wiring done on our Touareg, & I can't get normal Auto Elects to play with the wiring on it. In Sydney I have a great AE that works on the Touareg (ex-VW) & he'll hard wire it in when we're home.

So in the meantime I was planning to use the DCDC charger when we are in such a National Park, direct from the battery to an Anderson plug, so rather than running the car for hours to get any sort of charge into the Kedron batteries at the 13A if I connect the DCDC charger direct to the car battery & then to the Anderson plug on the van, I hopefully will be able to reduce the cars idleing time significantly.

That's the plan, anyhow.

What do you think? Would this work?

Cheers

Alan

[John and Ann]

Thanks Alan,

Glad to help.

My caravan charger is mounted in the van front hatch adjacent to the batteries, above the solar regulator and 240/12v power supply. Rather than using fuses as shown on the installation diagram I've used circuit breakers. This came about after bad experiences with melting fuses for the unit in the cruiser and discussion with a Redarc rep at one of the local shows. If you use fuses you really need to use the bigger version of the blade fuses.

I see no real reason you could not make up an interim kit to achieve what you want, certainly the Redarc unit will charge full current at engine idle. One thing you might be able to do is install Anderson plugs on the input and output of the DCDC charger and simply connect it between the vehicle and the van, just be sure to never mix up the input and output, paint the plugs perhaps, reversing won't damage the charger just won't charge the batteries.

I bought my chargers on eBay the prices were far cheaper, but, if your AE is a good mate he might do a better price, fit some Anderson plugs and post it off to you.

Things to look out for are:1. Is the wiring in your current Anderson circuit capable of carrying 50 amps, car and van?2. Is the fuse in the Anderson circuit of your car rated at 50 amps if not can it be upgraded easily?3. Is the fuse in the Anderson circuit of your van rated at 50 amps (probably not, mine was 30A, it's under the lid of the left most battery)?

You could alternatively make up a kit with some clips to connect to the vehicle, fuses on input and output and Anderson plug for van input, you'll still need to investigate the fuse size in the van and be sure to use adequate size cable and clips..

Either way, unless you're quite handy and close to the needed bits might be a challenge to make up this kit on the road. If you're AE can send it to you that would be the simple solution, unless you're in Perth in which case come round with a few beers and a charger and we can get it done in a few hours

Good luck, let me know how you go.....

John

[HAVAGO]

Simple parralelling is I believe a hangover from the days when your car batteries were of the same chemistry as you would have in your van, that is no longer the case. So my belief is the optimal solution for best long term benefit is DCDC charging.

Spot on John,

good sound advice.

Cheers

[Alan and Jayne]

G'day John

Thanks again for your answer, just fantastic, & your offer of assistance in installing it left me speachless. Thanks.

We're no longer in Perth, & are already heading north to warmer weather. As yet the DCDC Charger hasn't caught up with us, hopefully in the next day or two Aussie Post will find us.

The wiring in the Touareg will handle it, I also think the Kedron wiring will be Ok as well.

Once I get it all, I'll let you know the results.

Thanks again.

Cheers

Alan

[John and Ann]

Your most welcome Alan,

We will be following you shortly, well end of May heading off to Darwin and back to the Kimberley to get away from the cold, we might bump into you on our travels.

John

[RussnSue]

G'day

Batteries and battery charging are interesting subjects that always elicit a lot of useful information. I am a career "DC" person and have been working with batteries all of my life. I have come to the conclusion that lead-acid (including AGM and other "deep cycle" variants) and lead-calcium batteries are generally very forgiving and are often subjected to far more TLC than they actually deserve. Over the years I have also come to the conclusion that simple is best. This has been reflected in the system that I now have for my vehicle and van....

In my vehicle I have the cranking battery and an auxiliary battery. Between them is a manual switch that either isolates them or joins them together. When I'm driving I connect them together. When I'm parked up for the night I disconnect them. Everything I have fitted to the vehicle, post-manufacture, is connected to the auxiliary battery. This includes GPS, two-way radio, phones and chargers, laptops, car fridge extra lights etc. The aux battery is a lead-acid wet cell.

From the aux. battery I have wired very heavy cabling to the rear of the vehicle where the car fridge is located. This cabling continues on to the Anderson plug on the rear bumper. I upgraded the cabling from the batteries of the van to the Anderson plug that connects to the car so that I have heavy cabling throughout. When parked up I have a length of heavy cable that I connect from the van to the car. In other words, the van and the car are always connected unless we are off in the car somewhere.

At night the van batteries help the car aux. battery run the car fridge and other stuff. When driving, the alternator helps out with the van batteries. That's it! Nothing else. I don't care that the aux. battery is not an AGM battery and I don't care whether the charging regime is "not ideal" voltage-wise. We are only talking poofteenths of a Volt in most cases. The car battery and the auxiliary battery were both changed out in December after five years of service in very arduous conditions. You've got to be happy with that! The van batteries are as good as new four years on. The only thing I ever worry about is not discharging the batteries too deeply.

I never worry too much about how much current the alternator is delivering to my batteries either. The Sun is still shining as we drive along and that's what solar panels are for. I personally do not see a need for any form of DC-DC charger, nor do I see a need to run and inverter to charger batteries. All of these things have their own in-built losses and result in the Law of Diminishing Returns being invoked.

That said, when someone can come up to me five years down the track and tell me that their auxiliary battery is still as good as new because they've been using one of these buggery boxes, I will happily concede. Just my 2 cents worth.

Cheers

Russ