That looks like a pretty good explanation for anyone who wants to understand why a DC-DC charger is a good idea. Well worth posting John
Cruising Cruze said
09:47 AM Sep 17, 2015
Hi John
Thanks for that info
It will help a lot of people here
Cheers John
justcruisin01 said
02:27 PM Sep 17, 2015
Been running two of these for a few years now, the only way to go.
JC
Vince said
11:06 PM Sep 17, 2015
I am using a Redarc BCDC1220 DC-DC unit in our Tug and found it works a hell of a lot better than the previous dual system Rotronic setup.
As the info rockylizard has linked we found the DC-DC unit keeps the auxiliary battery charging at the 14.4v while driving, it also has Boost and Float function.
Very happy with the Redarc unit.
Vince
greyhoundtom said
03:57 AM Sep 18, 2015
Excellent article, thanks for sharing.
Cheers, Tom
Sharke said
08:03 AM Sep 19, 2015
If you decide to do a DIY installation and you have a late model vehicle like a Toyota or Ford they have a smart alternator installed. Smart alternators are temperature and voltage controlled by the ECU and have a temp sensor in the engine bay also only supply a maximum of 13.v volts to load and maximum to battery. This can be solved by installation of a relay to control start battery. You will need to check if your alternator is smart. www.baintech.com.au/faq/can-i-use-a-ctek-d250s-dual-in-a-vehicle-with-a-smart-alternator cheers Jeff
-- Edited by Sharke on Saturday 19th of September 2015 02:49:41 PM
greyhoundtom said
08:18 PM Sep 19, 2015
Checked that link but can't see a reference to any listing where you can check if your vehicle has a so called smart alternator.
And while it pushes the use of a relay to switch between two separate power sources, this would be more important in situations where both the cranking battery and the secondary battery are in the same vehicle.
In most instances where the secondary battery system is in a camper or van the connection between the vehicle and the van would be broken anyway, so a relay should not be necessary.
Cheers, Tom
PeterD said
09:03 PM Sep 19, 2015
There is no problem working out how your alternator behaves. Get yourself a plug in meter like this one. Plug it in before you start the motor. Observe the meter after starting the motor. If the system voltage drops to less than 13.8 V at any time whilst you are travelling then you need that that relay if you wish to use the D250S
And while it pushes the use of a relay to switch between two separate power sources, this would be more important in situations where both the cranking battery and the secondary battery are in the same vehicle.
This system is for remote use in vans and trailers. Standard basic DC-DC chargers use the drop in alternator system voltage to isolate the charger from the starting battery when the motor is switched off. The problem is the newer vehicles drop the system voltage to below the D250S running voltage. The relay contacts route the alternator supply to the solar input and the regular alternator input is ignored. This fix is specific to the D250S and most likely will not work with other models.
greyhoundtom said
02:41 AM Sep 20, 2015
Thanks Peter, as always clearly explained.
I'm getting a great education about the functions and pitfalls of low voltage, batteries, and charging systems in this place.
Gday...
I received this from a subscription I have ... it seems to be well written, researched and presented.
I offer it for its information value - perhaps the experts on the forum might want to enhance, confirm, or denigrate the article.
http://www.caravanworld.com.au/features/1509/dc-dc-battery-chargers-explained/?utm_source=cvw_newsletter&utm_medium=email&utm_content=review3_readmore&utm_campaign=cworld-160915&user_id=fef5569bff84bb3b1b3140fe484ae4bc1b07e5f3
Cheers - John
Hi John
Thanks for that info
It will help a lot of people here
Cheers John
Been running two of these for a few years now, the only way to go.
JC
As the info rockylizard has linked we found the DC-DC unit keeps the auxiliary battery charging at the 14.4v while driving, it also has Boost and Float function.
Very happy with the Redarc unit.
Vince
Cheers, Tom
If you decide to do a DIY installation and you have a late model vehicle like a Toyota or Ford they have a smart alternator installed. Smart alternators are temperature and voltage controlled by the ECU and have a temp sensor in the engine bay also only supply a maximum of 13.v volts to load and maximum to battery. This can be solved by installation of a relay to control start battery. You will need to check if your alternator is smart.
www.baintech.com.au/faq/can-i-use-a-ctek-d250s-dual-in-a-vehicle-with-a-smart-alternator
cheers
Jeff
-- Edited by Sharke on Saturday 19th of September 2015 02:49:41 PM
And while it pushes the use of a relay to switch between two separate power sources, this would be more important in situations where both the cranking battery and the secondary battery are in the same vehicle.
In most instances where the secondary battery system is in a camper or van the connection between the vehicle and the van would be broken anyway, so a relay should not be necessary.
Cheers, Tom
There is no problem working out how your alternator behaves. Get yourself a plug in meter like this one. Plug it in before you start the motor. Observe the meter after starting the motor. If the system voltage drops to less than 13.8 V at any time whilst you are travelling then you need that that relay if you wish to use the D250S
This system is for remote use in vans and trailers. Standard basic DC-DC chargers use the drop in alternator system voltage to isolate the charger from the starting battery when the motor is switched off. The problem is the newer vehicles drop the system voltage to below the D250S running voltage. The relay contacts route the alternator supply to the solar input and the regular alternator input is ignored. This fix is specific to the D250S and most likely will not work with other models.
I'm getting a great education about the functions and pitfalls of low voltage, batteries, and charging systems in this place.
Cheers, Tom
dibs