DC-DC battery charger under hood?

msand1977

Observer
Anyone know of a DC-DC battery charger that can be mounted under the hood? The ones I've looked at from Ctek, Redarc, and Sterling don't appear to be able to do this because it would be to hot for the charger.

Thanks
Matt
 
Anyone know of a DC-DC battery charger that can be mounted under the hood? The ones I've looked at from Ctek, Redarc, and Sterling don't appear to be able to do this because it would be to hot for the charger.

Thanks
Matt
So I did a quick review of Ctek's Catalog online, not having heard of them before.

The idea of having a DC/DC device charge your battery from another battery source such as your alternator is an interesting application. I need to do a little further research on Ctek for my own edification before I can weigh in knowlegably on their application and benefits.

Just keep in mind, that any device that consumes energy is going to dissipate some of that as waste (in this case HEAT) so you want to minimize the number of devices that you use to convert/transfer energy from one form to another or from one place to another...

Usually I use isolators to direct the charge supply (from the alternator while the engine is running) to one battery at a time depending on the needs. One by one each battery gets charged to its full capacity, without directly bridging the batteries together. Isolators are inexpensive and rugged and can fit in a tight space like under your hood.

I use battery switches to keep the batteries separated. Then when I need to tie the batteries together, I simply select the proper combination on the switch(s). By good circuit design, I can call on any (or all) of the batteries to provide starting power for my engine even if the starting battery is flat, or one or more of the batteries (including the starting battery) together perhaps to power some other device like an inverter when mandated by the situation...

Sometimes there is a need to use a DC-DC charger because the batteries are of different voltage's such as 6 vs 12 or 12 vs 24...

I would like to hear about your particular application and all the batteries and how you have them tied together or not. And can you tell me why you feel the need to use a DC-DC charger?

Regards,
RestorationRides

Sent from my Z981 using Tapatalk
 

Recommended books for Overlanding

Crossing the Congo: Over Land and Water in a Hard Place
by Mike Martin, Chloe Baker, Charlie Hatch-Barnwell
From $25.95
Morocco Overland: A Route & Planning Guide - Southern Mor...
by Chris Scott
From $29.95
We have a Cetek 250 dual mounted in the engine compartment and on our Botswana trip external temperatures reached 42 deg C and the charger was fine even though the specs state a max operating temperature of 50 deg C. Another option is the Projecta IDC25 Projecta.com.au that is designed for under bonnet installations with a max operating temperature of 80 deg C
98078CB5-FF4D-441D-AAC2-44E454AB01D4.jpeg
 

martnH

Member
Not a good idea.
In fact relocate both battery, the cranking battery as well.

The coast is some mount and wire but the battery will last so much Longer

Sent from my LG-H870DS using Tapatalk
 

1leglance

2007 Expedition Trophy Champion, Overland Certifie
I have both my batteries and my CTEK under my hood here in Phx Az and while I know heat is the enemy things have been working well for over 5yrs of service.
My CTEK unit is also getting power from my solar panel with no issues.
 

kevman

Observer
And can you tell me why you feel the need to use a DC-DC charger?
Why not?

Serious question though. For the price they seem like a no brainer. The Redarc Dual Input 1240 is ~$400US or so. Since voltage drop isn't a big issue anymore with cabin mounted batteries you don't need huge wires (~$100 saving), you no longer need a starter isolator (~$100 savings) and finally it's an MPPT controller for a solar set up (~$200 savings). I guess if you're putting your house battery in the engine bay, don't have solar, and have a strong alternator you don't need it. However most rigs on this site seem to have a cabin mounted house battery and a solar set up so wouldn't that make a DC-DC charger a simple no brainer?

Unless I'm missing something - which I might be - I'm still learning.
 

DiploStrat

Expedition Leader
Two comments, or maybe more:

-- A B2B still requires the same size wiring. Amps is amps. A B2B will help with voltage drop, but you still need properly sized wires.

-- The most common purpose of a B2B is to raise the charging voltage to the secondary battery, a problem with some Toyotas and Mercedes.

-- A B2B may also be useful in dropping the voltage and controlling the amp draw with a LiFePO4 battery. Also serving as an isolator when the voltage settings for an intelligent relay won't work.

Bonus points:

-- Some B2B also include a solar controller which can be useful in small setup.

-- Some B2B (e.g. CTEK) also include a trickle charge function for your starter batteries. This feature may be coming to others.
 

martnH

Member
And can you tell me why you feel the need to use a DC-DC charger?
Why not?

Serious question though. For the price they seem like a no brainer. The Redarc Dual Input 1240 is ~$400US or so. Since voltage drop isn't a big issue anymore with cabin mounted batteries you don't need huge wires (~$100 saving), you no longer need a starter isolator (~$100 savings) and finally it's an MPPT controller for a solar set up (~$200 savings). I guess if you're putting your house battery in the engine bay, don't have solar, and have a strong alternator you don't need it. However most rigs on this site seem to have a cabin mounted house battery and a solar set up so wouldn't that make a DC-DC charger a simple no brainer?

Unless I'm missing something - which I might be - I'm still learning.
The redarc you want to buy is a little baby

Which one you wanna buy? 20a? 25a? Or just 15a.

The alternator outputs 165amps
A commercial DC DC charger can output 100amps, but not the "hobby" dc-dc you want to buy.

And this is my advice. If you don't have a smart alternator, then dc-dc charge maybe even give you a faster charger to your battery. I understand you are under the impression that dc-dc charge will charge battery faster
And this is all marketing bullshit...

Sent from my LG-H870DS using Tapatalk
 

Recommended books for Overlanding

National Geographic Road Atlas 2021: Adventure Edition [U...
by tional Geographic Maps
From $23.44
Adventure Motorcycling Handbook: A Route & Planning Guide
by Chris Scott
From $10.09
Tortillas to Totems (Every day an Adventure Book 4)
by Sam Manicom
From $9.99
Road Fever (Vintage Departures)
by Tim Cahill
From $6.99
Deep Survival: Who Lives, Who Dies, and Why
by Laurence Gonzales
From $9.99

john61ct

Adventurer
They are sometimes necessary. See how you go charging directly off the alt first.

If 'smart alt' is the cause of the problem, see if the problem can be switched off.

Actually measure / log volts and amps into the batt while driving, $30 inline ammeter.

If you need a DCDC charger, then get one.

I prefer Sterling.
 

MANUCHAO

Aventurero
One of my vehicles has one of those Smart Alt......
The only thing I could do to make sure my Aux was charging was to run/turn-on the headlights....
This draws a current and tells my alt to start charging the main batt, as well as the Aux batt......
 
Top