DC2DC charger in a caravan

[Steve H]

Hi. I have just fitted a lithium battery in my caravan hooked up to a 100watt solar panel with an MPPT solar controller. I want to fit a DC/DC charger. Does this need to go in the caravan or should I fit it in the truck? I was thinking of using Anderson connectors to supply the charger along with 10mm2 wiring to supply a 20 amp feed and so I don't have to touch any of the vans original wiring as its still under warranty. This weekend we went away and just used the switch relay to charge the battery and it coped OK but don't want to risk any problems either with the battery or alternator. The solar panel is permanently connected to the battery to maintain charge when in use or in storage.
I have fitted a Victron MPPT 75/15 controller and a Victron Smart Battery sense. All weekend the battery voltage didnt drop below 13volts . Also do I need some sort of battery monitor to check SOC? The Victron app is quite useful for this but not sure if I need anything else to make sure everything is working as it should.
What do you think? Any advise or suggestions welcomed.

 

[Chris]

Really the DC2DC needs to be in the van with the battery. The supply to it then matters less and the run from the charger to the battery is minimal.

 

[Steve H]

Thanks for that Chris. I will have a look at some wiring and connectors to mount the charger in the van. I have been looking at the Sterling wildside chargers but that means cutting into the van loom and really want to avoid that if I can.

 

[David]

You may need to up your cable size from the truck to the charger, my 40 amp Redarc specifies 20mm2 if the cable run is over 5m. I have the Victron monitor works very well as long as you can get all the earths onto the shunt

 

[Chris]

I don't have any personal evidence but that from people that I trust say that Stirling have an extremely poor reputation.

 

[David]

A friend of mine has Victron Orion dc/dc and is very pleased with it so far and it does integrate with the Victron app might be worth a look
As for Sterling when we had our boat 20 years ago only problem boaters seemed to have was from sterling gear, not saying that is the case now but personally I would not risk it

 

[nick_the_fish]

Also worth checking out the Intervolt. @StarCruiser did a thread about them on here a while ago which is full of useful information. I've just put a Redarc on mine with a Smartshunt on my leisure battery. Expensive bit of kit, but very useful to know what is going on with the system.

 

[Steve H]

Thanks for all the replies.
@David I was looking at the Victron Orion DC/DC and using Anderson connectors at the back of the truck to connect to the caravan. That way I dont have to cut into the caravan loom and it keeps it simple to wire up and use. Also when I change the van I can easily remove it and fit it to my new one. I was thinking of using 10mm2 cable as I need a minimum of 20amps to charge the battery fully but the solar panel is keeping the battery fully charged when in storage. So I should only need to keep it topped up and the original wiring should take care of the fridge.
@Chris I think the sterling is too expensive for what is is and it uses the vans original wiring to shove upwards of 20 amps to power the fridge and battery. Not good.

 

[Allan M]

I use the Victron Orion Smart 12v/12v-18A (the smart has the bluetooth). I use it to charge my 95ah AGM. It's fitted no more than a meter away from the battery and its supplied by 6mm2 cables about 4M long. Over this length you would want a minimum of 10mm2 cable. It also has 6mm2 from it to the battery. The bigger the voltage drop the harder its got to work. I really needs to be close to the battery to correctly measure the voltage.

Why do you need to cut into the vans wiring? Just put your Anderson near the towball and run 10mm cable into the charger location in the van.

I don't know about their DC/DC chargers but I have a sterling mains charger in my motorhome and it works really well.

 

[Chris]

Well talk about timely. Just snagged a brand new Redarc DC3DC on Facebook. Wasn't really looking but couldn't help myself. Now I just need to work out what I'm going to do with it. Hilux? Metalian? 80 Series? Problems problems.

 

[Steve H]

@Allan M That is what I am going to do I think. I have been on Youtube looking at videos about charging lithium batteries properly and they use the Sterling Wildside DC/DC charger which utilises the 13pin plug and wiring on the caravan. But I dont want the wiring in the van altered as it still under warranty. The Victron looks simple to do and I can do it myself without affecting the warranty as it will be separate from the caravan wiring. I just need to source some 10mm2 wire, fuses and Anderson connectors and fit it all in.

 

[GeekOKent]

Well talk about timely. Just snagged a brand new Redarc DC3DC on Facebook. Wasn't really looking but couldn't help myself. Now I just need to work out what I'm going to do with it. Hilux? Metalian? 80 Series? Problems problems.

But what is the 3rd DC link going to do!

 

[Chris]

Replace an existing system Or I might use it under the bonnet for the second battery instead of the basic split charge

 

[Bodie]

Well talk about timely. Just snagged a brand new Redarc DC3DC on Facebook. Wasn't really looking but couldn't help myself. Now I just need to work out what I'm going to do with it. Hilux? Metalian? 80 Series? Problems problems.

I obviously need to be more on the ball Chris..... been looking for the very thing.
Be interested to know what ya think of it? and if ya see another one for sale giz a kick!!
J.

 

[Chris]

There is already another one for sale on the same thread. Used but at £275. Mine was a spanker still in the box. Some muppet hijacked the thread and said if anyone wanted that but missed it I have the same thing but cheaper. Oh great thanks. Hah never mind.

 

[Batts88]

It's usually recommended that the charger is fitted near the battery probably to reduce the cable length so less voltage drop. Depending on what you but they can be all in one a 12v charger/solar regulator and battery isolator. Also when checking the power left in a lithium I suppose you can go by the voltage if you have a chart that suits your brand of battery as some may vary in voltage but it's usually better to have a percentage meter just like a mobile phone does.

 

[Bodie]

There is already another one for sale on the same thread. Used but at £275. Mine was a spanker still in the box. Some muppet hijacked the thread and said

I have had a little search for it Chris, but can't find it........ must've gone!

 

[Chris]

I think he posted it in the other bloke's advert. So when my seller closed his ad down, his comments went with it. I said he was a muppet!

 

[Bodie]

Not to worry...... I'd still be interested to know what ya think of it though Chris...... once you've installed it into one of you many projects.
It's either that or Victron for me, which is more modular, (so if one module fails, you've not lost everything) but Victron units are really NOT designed for smaller rigs, they're bulky and take up so much room!!

 

[Chris]

No plans to install it anywhere at the second. I keep looking at it thinking, hmm what did I buy that for! Ha ha. I do that sometimes when I have a rush of blood to the head.