Best way to charge camper from vehicle

Gday

im about to take ownership of my new camper and just want to know if im on the right track.

in my patrol i have the normal everyday dual battery system. Now i have heard of some people running the power to a plug at the back of there car from the aux battery and plugging straight into the camper to charge the camper batteries whilst in motion.

my question is due to voltage drops etc would it not be better to do as said above but run a dc-dc charger in the tool box of the camper to boost the charge given???

any help greatful cheers

Hey mate, yes as you have said, the DC-DC charger in the camper is the best option.
However if you run some decent sized cable from your aux battery to a plug on the rear then that will definitely charge the battery sufficiently.

Ctek d250s will do the job and they are very well priced, also have a solar input as well.

Quote:

---

Originally Posted by dakka1

Gday

im about to take ownership of my new camper and just want to know if im on the right track.

in my patrol i have the normal everyday dual battery system. Now i have heard of some people running the power to a plug at the back of there car from the aux battery and plugging straight into the camper to charge the camper batteries whilst in motion.

my question is due to voltage drops etc would it not be better to do as said above but run a dc-dc charger in the tool box of the camper to boost the charge given???

any help greatful cheers

---

What Winnie said.
Which way you decide to go depends on two things essentially.
1. Your intended style of usage
2. How much you want to/can spend.

Re.1.
Some folk argue that the big cable & no DC to DC is the way to go, their reasoning being that the DC to DC charger will restrict the amount of amps compared to what the alternator can provide. However if the batteries are to be well cared for (& thus last for many years) they are best not discharged to levels which allow the alternator to put in more amps than a DC to DC charger. If you intend to travel daily the big cable will work, the camper battery will never be fully charged but will generally be sufficient for overnight. For longer stays at camp without driving a DC to DC charger will enable 100% charge of the battery, allowing you to camp for longer. Add some solar & you can set up for indefinite stays.

2. A DC to DC charger will cost more than a big cable, but for the reasons given above will probably be cheaper in the long run (not needing to replace batteries so often, & smaller cable is easier to run through the vehicle to an Anderson Plug). Buy a decent quality DC to DC charger (Ctek or Redarc) & get one with a reasonable amperage. e.g. a 40 amp one & a 10 amp one will both bring a battery to 100% full charge, but, dependent upon how discharged the battery is the 40 amp will do it in less driving time.

An alternative is to install a smaller DC to DC charger with a manual bypass, so if the camper battery is heavily discharged you can charge quickly up to around 70% to 80% capacity direct & then switch to the DC to DC to top it up. This would require both heavy cable & a DC to DC charger though.

A further alternative is to just go the heavy cable route, but use solar to top up the camper battery.

Some DC to DC chargers are also solar regulators saving the need to purchase the separate items. I have a Redarc 40 amp unit which does this, set up so that whilst driving batteries are charged by DC to DC & as soon as the ignition is turned off my roof mounted solar takes over.

Hey guys cheers for that.

I will prob go a dc to dc as i can get both ctek or redarc theough work. We camp for extended periods and just over nighters. So to give it 100% while driving is ideal as on the over nighters i dont setup the solar system i have.

As for the solar system i dont need the dcdc to have solar imput as i only setup the solar once we are stopped. Plus i have a prostar30m solar reg which does the trick regulating my 320w of power lol. Yes lots of solar power there but we run an 80L fridge lights water pump etc etc

Purely just want to charge the 2 105ah batteries as much as pos while we are in transit

my personal, honest and limited knowledge of these

DC to DC is an expensive rort

both your Alt and DC to DC will fully charge a battery

Alt will charge it at 75-140A depending on your Alt
and yes they seem to charge BOTH batteries without blowing them up of stuffing them up

DC to DC will only charge at 5-10A (the big "40A" DC to DC have not hit the market completely and are very expensive)
with DC to DC you are using your 2nd (or main) battery to charge the Camper one as well.......but over a longer period........
(yes they have Solar input on the regulator - but if you buy Solar they have the regulator as well......)
so
what is the point of having a DC to DC to charge 1 battery off another battery - when the Alt in your car does it any way


I would put a decent sized cable from your 2nd battery to an Anderson plug at the rear
depending on the size of your Camper battery, put an appropriate sized fuse at the 2nd battery end

save yourself about $200

it works for me, and my battery in my Van is always charged
and running lights and engle only, I get about 4 days before the battery is really needing a charge

looks like the debate is on. I have used both options before and both did the job. I have only recently purchased a Redarc DC - DC 20amp charger and I cant see the difference so far. I have 4 AWG cable running the length of the car to a 175 amp Anderson plug. I also have 4 AWG cable going to the DC - DC charger in the caravan. all good so far. My batteries were fully charged up from the alternator without the DC - DC charger which I purchased after advice from a mate who works in the battery industry. I will be doing more testing during summer. As my van is parked in the Driveway it has a smart charger hooked up to it at all times so the batteries are fully charged so while driving from home to my destination with the fridge running on 12v my batteries were never depleted while I was just charging from the alternator. I think if you start with a fully charged battery to start with then the alternator will suffice however if you start without a fully charged battery then the DC - DC would be the way to go. As I say this is the testing I will be doing during the summer. For me as we only stay in one place for 2 - 3 days at a time we also use a solar panel as well.

DC/DC Chargers have one major practical application plus a couple of bells and whistles.

They are a device that will take a low voltage supply with higher current which isn't suitable for charging a Battery and raise the voltage to the required level by reducing the available current.

If an installation has only minimal voltage drop from an Alternator source then the Alternator will replenish discharged batteries much quicker and more efficiently than a 20 or 30 amp DC/DC Charger.

If an installation has so much drop that the Alternator cannot charge the battery IE small gauge wiring thru Trailer Plugs etc or long small gaue wiring runs then a DC/DC Charger is a practical and useful solution

If you have heavy gauge wiring and Anderson Plugs or similar then a DC/DC Charger pretty much just keeps the manuf and retailers in beer money... and is also why some manuf make equipment to bypass the DC/DC charger so you can pay twice as much to "go back" to an alternator capacity feed whne that is better than your DC/DC output

Quote:

---

Originally Posted by the evil twin

DC/DC Chargers have one major practical application plus a couple of bells and whistles.

They are a device that will take a low voltage supply with higher current which isn't suitable for charging a Battery and raise the voltage to the required level by reducing the available current.

If an installation has only minimal voltage drop from an Alternator source then the Alternator will replenish discharged batteries much quicker and more efficiently than a 20 or 30 amp DC/DC Charger.

---

Yes & No.

The other big plus for a dc to dc charger is that it is a ‘smart charger’, unlike an alternator. It is the ‘smart’ function which (like a solar regulator or 240v smart charger) enables it to charge a battery to 100%. It can be argued that an alternator alone will charge a battery to 100% & it’s true , it will. However to do so it will take much longer than is practical & for anyone travelling & needing to recharge their battery fully every 24 hours it won’t happen. As I said earlier an alternator alone it will bring heavily discharged batteries up to around 70% or 80% capacity at a faster rate, but allowing batteries to become that discharged shorten their life, & charging them at a much higher rate is also not good for them. I am convinced that a balanced system with a dc to dc charger is preferential to alternator only charging.