New DC to DC Charger From Renogy-20 amps or 40 amps-Flooded/AGM/GEL/Lithium

[luthj]

Yeah, obviously you want to be conservative. Some enclosures have no problem shedding 50 watts without getting to much above ambient. There are too many variables to know over the internet, so a test is advised, ideally in warmer temps. Regardless, the rise above ambient will be fairly consistent. If the delta is ~20F, then it will be 70in/50 out, and 100in/80out etc.

 

[shade]

Depending on the enclosure, it may be worthwhile to set up some ducts to get air to and from the charger. Even a little air exchange could make a big difference, and since it already sports fans, it'll do most of the work without relying on convection.

 

[luthj]

As a note, ducting can cause overheating if it's undersized or long. So take care, as the fans in these units don't make much head pressure.

Another option for testing is a 40w incandescent lightbulb.

 

[shade]

I'm thinking more a loose duct that terminates near the charger case, not connected directly to it. I think that would avoid overtaxing the fans while still allowing fresh air to enter.

 

[Amp34]

That should help.

I was thinking more about environmental & use variables. There'd be a significant difference in the heat generated recovering after a deep discharge while in Death Valley in August compared to adding a minimal charge while in Leadville in February.

I’m in Canada. I’m hoping the heat may keep the battery above freezing.

How do most people keep their battery compartments cool? Must be a common issue?

Good call on the incandescent bulb, although I’m not sure if I have one round any more.

I think a thermometer controlled fan is going to be a simple solution. There’s not a huge amount of heat being generated.

 

[luthj]

My batteries are under the vehicle. My electronics compartment has about 15 square inches of inlet and outlet vent area (high and low). I also have a fan which runs when my inverter does. There are audio cabinet thermostats you could wire up to run some small computer fans for exhaust purposes. My electrical cabinet doesn't get warm with 30W of heat, but running 2kw through the inverter does need powered venting.

 

[RigidYota]

Annoyingly Renogy Canada don’t have these available yet, but US and Australia do.

The Australian site only ships to Australia and the US site ships to Canada, but charge $150USD for delivery... The only places that sell them also either drop ship from Renogy (and charge the same shipping) or don’t ship to Canada (Amazon).

In contact with their Canadian CS at the moment and apparently they may be available in a couple of weeks, but that was about a month ago. Waiting for a reply back for updates.

I sent them an email too, was also Flora that replied. Here was the reply for the Canada store.

"Thanks for reaching out to Renogy CA.
Yes, the DC to DC charger will available on Canadian site by the end of Aug or the mid of September."

I may wait and buy it there, may be easier for warranty

 

[PcRabbit]

Hi everyone
I'm hoping someone can please help me out or point me in the right direction. I'm putting the 20amp version into my old caravan. At the moment I've nothing to keep my battery charged while I'm driving at night with the fridge running in the van (I'm in the process of fitting solar for off grid camping to) My ute has an arc pac set up in the rear charging off the main battery with a battery disconnect fitted. The plan is to run decent cable via anderson plugs from the arc pac to the renogy dc dc charger in the caravan. My question is besides does this sound ok? How would I trigger the unit to turn on? Would splicing into the incoming wiring from the ute work so when the caravans hooked up and plugged in it starts up, or do I need to run a separate lead from the arc pac to fire it up? Sorry for the long read, looking forward to any input, cheers Peter

 

[shade]

Hi everyone
I'm hoping someone can please help me out or point me in the right direction. I'm putting the 20amp version into my old caravan. At the moment I've nothing to keep my battery charged while I'm driving at night with the fridge running in the van (I'm in the process of fitting solar for off grid camping to) My ute has an arc pac set up in the rear charging off the main battery with a battery disconnect fitted. The plan is to run decent cable via anderson plugs from the arc pac to the renogy dc dc charger in the caravan. My question is besides does this sound ok? How would I trigger the unit to turn on? Would splicing into the incoming wiring from the ute work so when the caravans hooked up and plugged in it starts up, or do I need to run a separate lead from the arc pac to fire it up? Sorry for the long read, looking forward to any input, cheers Peter

I'm sure someone will be along to correct me, but daisy chaining the Arc Pac to another charger sounds like a bad idea, no matter how it was done.

If the positive wire charging the Arc Pac can handle the additional current required to power the Renogy charger, you could put a + bus bar near the Arc Pac. Run a separate wire from the bus bar to the Arc Pac, and another from the bus bar to the Renogy charger in the caravan via an Anderson plug. If the existing wire can't handle the combined load, you could run a second + from the engine bay to the rear Anderson plug, or replace the existing wire with a heavier gauge and use a bus bar. I'd go the bus bar route to simplify things, but that's me.

 

[john61ct]

Think not of the batteries as nodes, but the **wiring circuits** is what you are tapping into or extending.

The round-trip distance, the gauge of the wire, the devices and terminals in the path, creates a certain voltage drop at each location.

If the result is too low, either increase the wire gauge or move to a DC-DC charger placed near its target bank.

Where needed, a VSR/ACR prevents one circuit's loads from draining batteries designed to be used for another segment.

In some cases the DCDC acts to do this since it only allows current to flow in one direction.

But as above, the Renogy uniquely required a switch for that direction too.

Make a schematic rough drawing and post it, maybe worth starting a new thread to attract better / more responses.

There's another buncha smart codgers over on caravanners forum, tons of past threads there about exactly this scenario, and there do seem to be specific conventions in the Aussie community.

 

[Ranger Steve]

Just ordered mine!

 

[biggoolies]

trying to understand if anyone as the knowlege. if i have this 20A dcdc charging the battery, will my solar controller that is independantly attach the the same battery will also be charging at the same time?

so 20A from dcdc plus 10A from my solar for a 30A when the truck is running?

Yes. Consider electricity like water from a water hose. Two separate water hoses combined will not shut off the other but the two will combine.But as the battery fills up there is more resistance to the current coming in so you won’t have 30amps going in as it is being topped up.

 

[RigidYota]

The Canada site has the Charger listed now, about 100$ more than i expected....

Battery Chargers

Renogy provides high-quality solar panels, inverters, lithium batteries, and solar charge controllers for off-grid solar systems. Shop with confidence for reliable products, expert advice, and exceptional customer service to meet your energy needs.

ca.renogy.com

 

[john61ct]

$20 less than I expected

 

[Amp34]

They’re having a giraffe! No wonder they’re charging so much for delivery from the US. It basically makes them the same price.

Definitely going to get it ordered to the US border and pick up when I get my GFC.