Redarc Trailer Charger mounted inside the Ollie for 100% lithium charge

[John E Davies]

46 minutes ago, mjrendon said:

Are you going to use the 12v source from the 7 pin connector and place this Redarc unit inside the trailer?  

Exactly, I will wait on choosing an exact location until I receive the unit (back ordered for a month). It will probably go under the rear bed, on the inside of the fender well, a little aft of the inverter. I am going to be mounting some other heat generating devices (one for sure, possibly two, MPPT solar controllers) in that area and also near the existing PD converter. One major concern is cooling air, where does all that extra heat go? Those compartments are quite isolated in terms of air movement. They get hot in the summer and cold in the winter. I am going to add 4 inch round inlet vents at floor level, a computer cooling fan under the battery box, holes in the battery box, and additional exit vents up high, in an attempt to “condition” those spots. Keep the chargers cool, keep the new lithium batteries cooler in summer and warmer in winter.

This should move enough air (38 cfm), it is super quiet and it sips power (70 milliamps):

 

 

I prefer this approach to just ducting furnace heat over on that side, and hoping it gets where it should go. Furnace air does nothing at all to reduce the electronics heat load in summer..... I think this makes more sense than using an electric heating pad under the batteries.

John Davies

Spokane WA

Edited December 23, 2020 by John E Davies

[mjrendon]

Thanks for the update.  

I have plans for two MPPT controllers as well. The second controller would be used for external PVs when camping, so it would be available when towing. 

An alternative solution might include using the second MPPT controller by substituting the PVs when towing with a 24V at 5 - 10 amp boost (step-up) power supply with its power sourced from the 7pin 12V supply but triggered using a relay tied to the marker lights.  

When camping, the marker lights would be off and the 24v power supply would be bypassed by the relay so the external PVs would work as intended.

 

Edited December 23, 2020 by mjrendon

[John E Davies]

That little step-up power supply is interesting, however you could only get 5 amps at 24 volts, with a 10 amp 14 volt input current. An MPPT solar controller is pretty efficient, around 98+%, but that is still not much power from the truck when you are towing. Plus you would need some way to limit the current draw to 5 amps at 24 volts, or it will burn up, can the Victron MPPT controller be programmed to do that?

The Redarc unit puts out a reliable 11 amps at 14.5 volts, which tapers off right at the end of the charge cycle. I haven’t seen a similar device anywhere, it makes a whole lot of sense, with more and more RV owners switching to lithiums as their lead acid ones bite the dust.  The Redarc unit is very nice, and a very high quality item, but I expect the price would be more like $125 than $250 if a mainstream manufacturer started churning out lots of similar ones.

John Davies

Spokane WA

Edited December 23, 2020 by John E Davies

[mjrendon]

The 

49 minutes ago, John E Davies said:

That little step-up power supply is interesting, however you could only get 5 amps at 24 volts,

I believe that a DC step up power supply could be sized to provide 160 watts, which would be the same as the Redarc.  I will test the 5A 24V DC 120 watt unit with the MPPT controller to see what it can deliver over time and take some temperature measurements.

I also like your 12V fan plan.  How will you get the air flow into and then out of the battery compartment?

Edited December 23, 2020 by mjrendon

[John E Davies]

24 minutes ago, mjrendon said:

 

I also like your 12V fan plan.  How will you get the air flow into and then out of the battery compartment?

I need to look closer before I order a fan, but I think it will fit under the fiberglass beside the aluminum support structure. If so, then just drill a 4” hole at that location, mount the fan under the fiberglass (blowing air upwards), run wires to a nearby switch. Drill a bunch of big holes in the sides near the top to let the heat escape. Obviously the compartment door vents should be covered and the door itself well insulated.

This is still in the planning stage. Even without a fan in the bottom hole, there should flow a good bit of airflow through natural convection, but only if there are openings inside the cabin for it to enter and exit. Cool air in down low, warm air out higher up. Without those, the heat will remain trapped in the box. I have already located some aluminum screened 4” grills to use there. These are aluminum and should withstand a light kick. .... https://www.amazon.com/gp/product/B000BQM5EC/ref=ox_sc_act_title_2?smid=A2JIG2D2ZKIQO8&psc=1

John Davies

Spokane WA

[John E Davies]

I took some measurements, and on MY hull #218, I can mount the fan as shown. I might have to trim the corner off the support angle for the floor. The support assembly comes out easily since it is adjustable with a bolt or bolts (I added a second one already, they forgot to install it.)

 

 

 

There is no room further outboard from there since the floor sits directly on top of the wheel well. Note the lack of large area washers under the tray mount bolts to distribute the load. Grrrrrrrr! 🤬🤬🤬🤬

John Davies

Spokane WA

 

Edited December 23, 2020 by John E Davies

[John E Davies]

I changed my mind about the round upper vents, I am going to mount three of these Perko vents (used in the battery compartment door) directly below the join seam with the pantry, to exhaust the heat out of the battery area. It is a complete dead end heat trap otherwise.

https://olivertraveltrailers.com/forums/topic/4843-help-me-id-this-battery-door-vent-i-need-three-but-preferably-in-a-bigger-size/

John Davies

Spokane WA

 

 

Edited December 23, 2020 by John E Davies

[Galway Girl]

On 12/23/2020 at 10:44 AM, John E Davies said:

I am going to mount three of these Perko vents (used in the battery compartment door) directly below the join seam with the pantry, to exhaust the heat out of the battery area.

I'm following this closely.

 

 From what I've read am I interpreting the location for the redarc correctly and the venting in/out?

1) You will mount the Redarc unit under bed (street side) of the trailer. 
2) Your source to power for Redarc will be a connection to cables that are currently running to the batteries from the 7pin of the trailer.
3) For cooling, you are bringing in cool inlet air into  the battery box with a small fan mounted under the battery box.
4) You will open up some inlet holes into the under seat area for the box fan to pull in air from near the floor.
4) The outlet air from the fan pushing into the battery box will go back into the trailer from the battery box...and through new chrome vents just under the pantry.

I'll re-read but I'm very curious what you learn as I'm just a month or two behind in a similar project.

Craig

 

 

Edited January 4, 2021 by ctshort09

[John E Davies]

39 minutes ago, ctshort09 said:

I'll re-read but I'm very curious what you learn as I'm just a month or two behind in a similar project.
Craig

I will start a new thread when this is done, there is still much to do (and drill).

John Davies

Spokane WA

[Galway Girl]

Thanks John...as ever your posts help us all improve our Ollies.

CS

[John E Davies]

I ordered my charger a long time ago.... it finally is back in stock and ready to ship, if anybody wants to get one, plus a free Redarc hat.😬

https://www.etrailer.com/Battery-Charger/Redarc/RED96FR.html

John Davies

Spokane WA

[GAP]

On 12/22/2020 at 7:43 PM, John E Davies said:

Exactly, I will wait on choosing an exact location until I receive the unit (back ordered for a month). It will probably go under the rear bed, on the inside of the fender well, a little aft of the inverter. I am going to be mounting some other heat generating devices (one for sure, possibly two, MPPT solar controllers) in that area and also near the existing PD converter. One major concern is cooling air, where does all that extra heat go? Those compartments are quite isolated in terms of air movement. They get hot in the summer and cold in the winter. I am going to add 4 inch round inlet vents at floor level, a computer cooling fan under the battery box, holes in the battery box, and additional exit vents up high, in an attempt to “condition” those spots. Keep the chargers cool, keep the new lithium batteries cooler in summer and warmer in winter.

This should move enough air (38 cfm), it is super quiet and it sips power (70 milliamps):

 

 

I prefer this approach to just ducting furnace heat over on that side, and hoping it gets where it should go. Furnace air does nothing at all to reduce the electronics heat load in summer..... I think this makes more sense than using an electric heating pad under the batteries.

John Davies

Spokane WA

Sounds like a great and worthwhile project, John.  I can almost wrap my brain around the approach.  Question is that you mentioned it will assist in cooling the battery box in summer and heating it better in the winter.  The former makes immediate sense but I can't picture why the latter would work.  Is the assisting heat source going to drawing ambient air into the box from the under street side bed area and, if not, what type of dedicated heat source were you considering?

Thanks much,

GAP

[John E Davies]

1 hour ago, GAP said:

Sounds like a great and worthwhile project, John.  I can almost wrap my brain around the approach.  Question is that you mentioned it will assist in cooling the battery box in summer and heating it better in the winter.  The former makes immediate sense but I can't picture why the latter would work.  Is the assisting heat source going to drawing ambient air into the box from the under street side bed area and, if not, what type of dedicated heat source were you considering?

In cold weather, the  warmer cabin air (from the furnace registers ) will be drawn into the electronics compartments via the lower 4” round holes I am adding (and some warm air will be drawn from under the floor) and then the air is pulled up and through the battery box, and out the top vents just below the pantry. It won’t be a huge airflow, but the fan consumes almost no power (0.07 amps) so it can run 24 hrs with minimal affect on the battery load. The main idea is to get rid of the dead air and replace it constantly with conditioned air from the cabin. 

It should work. How well, is the big question. I will have a battery temp sensor, so I can tape off the vents, see how it reads, and untape the vents and operate the fan  for a few hours. I would expect to see a distinct temp change. And I hope the pantry temp will also be a little better. It and the closet both need airflow. I may add a fan at the closet up high, with holes drilled in the floor right next to the door opening, to get it “moderated”.

I have pretty much finished with the venting, I still don’t have the Redarc charger. Soon I hope..

John Davies

Spokane WA

Edited January 13, 2021 by John E Davies

[GAP]

Thanks on that John.  I'll keep an eye out to see your update.

I've been camping in the cold here in New England a couple of times since getting my E2.  As far as I can tell, after a number of tests, the battery heating pad is having zero effect on the battery internal temps.  It may be that the light is on but no one's home - meaning that the battery pad light works but not the pad itself.  Even after hours at around freezing temps, there is no effect and I cannot feel any difference on the bottom of the battery tray.  Will eventually figure out if the pad is the problem but, either way, feel it is worth it to be able to do as you suggest and be able to condition air in the battery box by sharing flow through from the cabin.

[John E Davies]

2 hours ago, GAP said:

 Will eventually figure out if the pad is the problem but, either way, feel it is worth it to be able to do as you suggest and be able to condition air in the battery box by sharing flow through from the cabin.

If you have a volt ohm meter it should be very easy to check. if you have a clamp-on (inductive) ammeter like this .... Uni-T B4Q094 UT210E True RMS AC/DC Current Mini Clamp M W Capacitance Tester ... it take all of thirty seconds. and you can use it for testing the electric brakes, or any circuit where you can access a single wire (not a bundle). It is excellent and I highly recommend it.

John Davies

Spokane WA

Edited January 14, 2021 by John E Davies

[GAP]

On 1/14/2021 at 12:22 PM, John E Davies said:

If you have a volt ohm meter it should be very easy to check. if you have a clamp-on (inductive) ammeter like this .... Uni-T B4Q094 UT210E True RMS AC/DC Current Mini Clamp M W Capacitance Tester ... it take all of thirty seconds. and you can use it for testing the electric brakes, or any circuit where you can access a single wire (not a bundle). It is excellent and I highly recommend it.

John Davies

Spokane WA

I do have a clamp on meter but on a quick glance, saw no single runs off the heating pad to be able to wrap around to check for load.  Will have to take another look.  the tail that runs to the negative is a double so I would assume that covers the led on the on/off switch.  I believe there  is a single that runs to the positive.  

[John E Davies]

New related threads started here: 

https://olivertraveltrailers.com/forums/topic/5270-how-to-redarc-dc-to-dc-11-amp-output-trailer-charger-installation/

and here:

https://olivertraveltrailers.com/forums/topic/5301-how-to-lithium-battery-powered-vent-system/

Thanks,

John Davies

Spokane WA

[Fritz]

Kudos not only on the installations, but also on the thorough explanations, photographs, material sources, etc.  It's contributions like these that give this forum so much value.