Redarc DC-DC Battery Charger

[NRALIFR]

I’m in the process of installing a Redarc BCDC1225D battery charger in my truck camper. I got it installed enough yesterday to give it an initial test, and was pleased to see that with the truck idling, a little over 20 amps was flowing into the battery according to the Trimetric panel. It’s rated for a maximum of 25 amps.



The Redarc charger works similar to a solar controller, taking DC voltage from the truck batteries and alternator that normally would be less than ideal for charging, and boosting it up to 14.6, 15.0, 15.3, or 14.5 depending on which charging profile is chosen based on battery type. In fact, this particular charger has a built-in MPPT solar controller and an input wire that can be connected to a solar panel.

Heavy cabling is still required in order to get the rated charging current from the Redarc charger. I have 4 AWG welding cables run from the truck batteries to a 2-Pole Pollak Connector in the front of the truck bed. From there, the 4 AWG wires continue through the camper umbilical cord directly to the TC battery, with the +12v wire running through the Redarc charger first.

For some reason, Lance had the 12v wires from the umbilical cord running to this low voltage panel first, rather than directly to the TC battery. This added several feet of extra wire to an already long run, and was limiting the amount of battery charging I could get from the truck. On our last trip with the camper, one of the screws on the ground bar on the right loosened up and got hot. The screw was for the -12v wire from the camper umbilical cord, so the TC battery was getting almost no charge.



Due to the cramped quarters and limited amount of space available to mount the charger, this has been a major chore to install. Routing the wires from where the umbilical cord enters the camper to the battery box and Redarc charger required removing the water heater in order to get the wires under and to the side of it. This is where it’s going to sit in the cabinet under the galley sink. The battery box is to the left of the Redarc, behind the panel with the bus bar on it.



While the water heater is out, I’m also taking the opportunity to make a couple of other changes that couldn’t be done with the water heater installed.

I prefer to run the fridge in AC mode from an inverter while on the road. I put a battery charge meter on the front of the camper several years ago so I could keep an eye on the battery voltage. The meter just has a series of red/yellow/green LED’s that I can see in my side mirror, and since it’s not displaying digits, it doesn’t matter that I’m seeing a reverse image in the mirror. I don’t really need to know the precise voltage, I just need to know if the state of charge is going up or down. Between the charge meter, and a wireless thermometer I have in the fridge, I can tell when the fridge cooling unit is on or off, and if the camper battery is getting some charge current from the truck. .



When I first installed the meter, I was hauling the TC on a ‘95 F350. I put it in the hole on the right. When I got an F450, because it’s wider I had to add some extensions to the swing-out brackets on the front jacks, which made them swing in further and cover up about half of the charge meter face. I moved it to the left a few inches, and I’m planning to install a waterproof remote switch for the inverter in the old hole. The old remote switch was inside the battery box, but it will be more convenient if it’s in this location.

This is what’s under the water heater. I’ve cleaned this area up a lot.



I still have some work to do before I can put the water heater back in. I have a new battery disconnect switch ordered, and it will be easier to install If the water heater isn’t there.

:):)

[cptqueeg]

Really want to thank NRALFR for his dedication to this thread and posting the link in my related thread. And thanks to all the others that contributed as well.

I learned a LOT.

[NRALIFR]

Stacey, stacking the Redarc chargers for increased charging capacity is something I hadn’t even considered when I bought the first one. That’s an interesting option, and I’d like to see that just from a curiosity standpoint. My physical space limitations would make that a bit challenging, but not impossible. Not just for the charger itself, but for the added batteries that would be driving that need. I’ve given it considerable thought for sure! The usefulness of the Redarc has actually exceeded my expectations, which is why I didn’t hesitate upgrading to the 40 amp model. After selling the 25 amp unit, there was very little out of pocket expense.

Charles, I gave some thought to doing exactly what you suggested and remote mounting the fuse for the DC element, but decided there were a couple other reasons why I preferred running the fridge in AC mode vs DC. One big reason is that I had installed a remote switch for the inverter on the front of the camper so I could turn it on and off without having to go inside. It’s good for when we make a stop just for shopping or sightseeing, and want the fridge to run on LP for a while. The fridge also won’t auto switch from DC to AC mode, so you have to remember to do that manually when you plug in to shore power.

That remote switch came in handy on our last trip after making a stop at an antique store. We got back on the road and I remembered that I hadn’t turned the inverter back on, so I asked one of the five girls that was traveling with me (different story) to open her window and flip that remote switch for me. Take your hat and glasses off first, though! :B

For reasons I could never determine, the fridge in this camper has never been able to run reliably on LP while driving at hiway speeds. I tried every suggestion for fixing it, and was only able to improve it slightly. I finally gave up beating my head against that wall.

As for the DC mode, the heating element is still there and I wouldn’t hesitate to use it in a pinch, but I’m not going to rely on it for continuous use any longer. This was actually the second time the DC element had done that. The first time was when I thought maybe the reason the fridge performed so poorly in DC mode was due to a defective heating element. When I tried to find a new 215 watt element, I found they were out of production. A parts dealer claimed to have a substitute, but it was about 20-25 watts hotter. I bought it, and while testing it overnight it burnt the Dinosaur control board bad enough (again, without blowing the fuse!) that the DC mode would never work again. I had to replace the control board as well as return the heating element.

I like the physical packaging of the Redarc unit myself. Even though mine is installed inside the camper out of the weather, there’s still the possibility of it getting wet due to all the plumbing that’s around it. It wouldn’t be the first time I’ve had a water leak there! :W

:):)

[CharlesinGA]

Glad to see you return for an update. I started reading this thread and realized it was OLD but kept reading, somewhere in there, someone asked about The 25 amp vs the 40 amp and I was thinking, "thats part of why he upsized the wiring, so he could upgrade if needed" and sure enough that is what you did.

One other thought is that it might be of benefit to remote mount the fuse for the 12v element that burned the connections, some sort of inline fuse holder, with large enough wires, or a standalone fuse holder wired to the circuit board with heavy wire.

I have a Bigfoot trailer and intend to upgrade the battery system on it to a couple of large AGM's and when I do, I will install a Redarc unit and the cable from the front of the truck to the rear, Circuit breaker up front, Anderson connector, all of that. I do not have a three way fridge, but it seems that it would be a good thing to have, since you are able to make it operate properly on 12v. Somewhere I read of someone having problems with a propane fridge not holding a fire on the road and they install a piece of A/C fiberglass filter on the inside of the side vent to dampen the wind stirring around in the compartment and the unit operated fine after that.

I had been looking at the Redarc units in part due to their environmental sealing that would allow me to mount the unit on the tongue of the trailer under the fiberglass cover.

Thanks for the info.

Charles

[S_Davis]

They work well, I have been using the 50amp model and it has been the only charge source to run my portable compressor fridge, charging batteries for my work tools and other 12 volt loads. It is working so well that as my power needs increase I am adding another 50amp charger and two more Trojan T-105s.

[NRALIFR]

I’m glad these old topics stay open now, instead of closing after a year of inactivity. I don’t know if that’s intentional, or just another “feature” of our vintage forum platform, but I like it. It gives me an opportunity to update this saga, and let you know how things have worked out over time.

Just to recap, when I opened this, I was installing a Redarc 25 amp DC-DC charger. I chose the 25 amp model because it’s price was about all I could stomach then. I think it was about $360 at the time, and the next larger model (40 amp) was about $80 more. My intended use was to support running the fridge in AC mode from an inverter while driving. The fridge pulls about 28 amps when the AC heating element is on, but it’s not on all the time. I would manage the power deficit by keeping the fridge set on one of its lower numeric thermostat settings.

That worked pretty much as planned. The fridge was staying cold enough, and the camper battery was staying charged enough. Then on a whim, I decided I’d try it on DC mode. I had given up on using that mode several years back because it just couldn’t keep up with even mild ambients without letting the fridge warm up to unsafe temperatures. I had pulled the fuse for the DC heater so I wouldn’t accidentally set it on DC and run the battery down.

I put the fuse back in, and set the Fridge to DC mode. We were on a trip out west, and were driving between Tucson and Joshua Tree NP. I remember the high that day was 113°. I have a wireless thermometer in the fridge to monitor the temperature from the truck cab, and to my surprise the fridge was able to keep up just fine.

After puzzling over this for a while, I concluded the Redarc charger was keeping the voltage in the camper to a much higher level than when I just had the larger gauge wires from the truck. The DC heating element was apparently putting more btu’s into the fridge cooling unit than it used to, making it work better. Not as good as the AC element, but MUCH better than it used to work. This was good news, because the DC heating element only pulls 18-19 amps, which turned my charging power deficit into a surplus. Whoohoo!

That worked great for several trips, but I eventually started noticing some intermittent cooling issues in DC mode where it seemed to not be able to keep up for a while, then it would start working normally again. Then on the last day of a trip a few months ago, it clearly wasn’t cooling at all in DC mode. I switched it back to AC mode for the remainder of the trip.

Once we got home and I had time to do some troubleshooting, I very quickly found that the DC fuse had gotten hot enough to melt its plastic covering, and scorch the Dinosaur control board around the fuse connectors. The fuse wasn’t blown however. After pulling the fuse and reinstalling it, the DC element started working again. I decided then that I need to go back to AC mode on the fridge, but I don’t want to have a power deficit any longer. I bought a portable compressor fridge almost a year ago, and want to be able to bring that along on some of our trips when it’s needed. It can also run in AC or DC mode, and DC mode is the most power efficient.

Fortunately, when I installed the 25 amp charger I upsized the wire gauge to 4 from the 6 AWG that was recommended. Upgrading to the 40 amp Redarc and some new fuses was a plug-and-play install, and I sold the 25 amp unit on eBay. The new unit also has a solar input, and I’m still planning on adding a roof mounted panel someday.

We just returned from another trip of about a week and a half, and the Redarc performed flawlessly. The weather was poor-to-awful the entire time. We were under a winter storm system in Texas and Oklahoma that would have rendered a roof solar panel of little use. The best weather we had most of the time was gray and overcast. We had rain, sleet, and snow on some days. I think think the last two days were the first sun we had. We drove about 2200 miles during that time though, arriving at our overnight stops after dark most days. The camper battery was always very close to fully charged when we stoped. If I remembered to switch on our 12v mattress heating pad a few hours before we stopped, our bed would even be warm.

We were out 10 nights, and the coldest night we had was mid-teens. We had 15 amp power 4 of those nights, and we used an entire 30 lb cylinder of propane for the trip. I used the built-in 3600 watt generator for the microwave only, and never had to get out my Yamaha 1000 gen.

This is pretty typical for the majority of our trips, where there is a mixture of work and play.

:):)

[MEXICOWANDERER]

I suspect if Watt hour ratings were listed for capacity instead of AH, then AGMs would achieve the higher number.

LY

You bet!

When Delco launched their dysfunctional flooded calcium/calcium battery in the 1970's they had a program of public awareness of the battery's energy measurement in watts. All of it came crashing down when the public resistance arose when replacing the battery. Why? The price was 20% higher than the Globe Union made Die Hard Sears & Roebuck battery. Not only was Globe Union's battery cheaper and better it boiled when mated with the GM alternator manufactured for the Delco calcium/calcium battery. The setpoint on the 1116405 regulator was a remarkably high 15.0 volts. The disaster continued. Boiling replacement lead antimony batteries made short work of the parallel program introduction of copper plated aluminum battery cables.

Because of Price Club's satisfaction guarantee I decided to use Delco VOYAGER sealed Delco RV batteries. I would purchase three batteries, take them to Mexico, and about 15 to 30 cycles later they lost half their capacity. Took them back dead as cork and got a "Red Eye Delco Voyager" cash refund. The next autumn I would repeat. John Booth who went on to Costco senior management, told me the Delco battery was the worst mistake automotive wise that Costco ever made.Of course it didn't rival the JC Penney Armageddon of the Forever Battery but Booth made a nasty face at the memory. Saul Price at the time was said to have yelled Never Again! Not one more Delco product!

The voltage "Span" is thinner between batteries that do not use calcium in the positive plates. The higher the antimony the lower the voltage requirement sinks. If the battery is a 1.50% hybrid, with calcium negative plates and low antimony in the positive plates the span becomes higher. Because hybrid batteries are not cycled their use and care is of minimal interest to consumers.

The more watts a battery stores, the more energy it contains. The only battery that can withstand cycling and offer more watts is an AGM when engine cold cranking power enters the game.

If an individual is young enough
If a battery bank is large enough
And important enough to warrant an expensive voltage compensation program, then even a thousand dollar compensator can pay for itself several times over.

[landyacht318]

Good to hear it is working well.

Higher DC voltages reaching a DC heating element will work much much better, as you have found out.

In general Higher DC voltages make everything DC work better.

And While batteries are rated in Amp hours, and AGM bateries of the same size of their flooded brethern have lesser Ah ratings, tghey hold higher voltages during that depletion.

I suspect if Watt hour ratings were listed for capacity instead of AH, then AGMs would achieve the higher number.

The lower my battery voltage, the hotter my DC to DC laptop converter runs, and my AGm is almost always 0.2 to .3v higher for the same Ah removed, compared to my previous flooded.

[NRALIFR]

I’m really liking this Redarc DC-DC charger.

I’m in California right now, Desert Center to be exact, where today’s high was 113. Driving from Phoenix today the fridge was running in DC mode, and for the first time in the 15 years I’ve owned this TC, the fridge was holding its own in extreme heat using the DC heater.

Temps in the fridge bounced back and forth between 35 and 38. It may have even been cycling off and on. When it’s in DC mode I can’t tell when it’s cooling as easily as when it’s in AC mode because the battery SOC meter on the front of the camper stays with it’s highest indicator lit all the time. When we stopped this evening, the Trimetric said the battery was at 97%.

I have to say that despite the Redarc’s painful price, and a slightly difficult installation process due to the limited amount of space available in my camper, I would highly recommend this to anyone needing to improve the charging performance to the camper battery from the truck alternator.

Remember, you must follow the manufacturer’s recommendation regarding wire sizing based on the length of the run from the truck batteries to get the full rated charge amps from the Redarc.

Remember also that this unit has a built in MPPT solar controller, and I could install a panel on the roof and connect it to the Redarc if I wanted. I may try that some day.

My only question now is “Is it reliable?” I’ll let you know.

For now, I give it a thumbs up!

:):)

[NRALIFR]

I’ve finally gotten a chance to see what the Redarc DC-DC charger does in real-world conditions. We’ve been out for a few days on a business and pleasure trip, and so far I’m very pleased with its performance.

I ran the fridge in AC mode from the inverter long enough to see that the camper battery stays in much better shape now. I do still have to manage the fridge temperature setting so it doesn’t just run continuously though. The Redarc charger puts out a maximum of 25 amps, and the fridge running in AC mode pulls about 33 amps. So, if I set the temperature on the fridge too low, it won’t cycle often enough and the battery doesn’t get enough charging amps to make up for the ~8 amp draw when the fridge is cooling.

What I’ve discovered just recently though is that since installing the Redarc, the fridge DC mode works well enough that I can now run it in that mode on the road. Even if the 215 watt DC heater is on 100% of the time, there are still charging amps available for the camper battery. The DC mode also seems to be working better than I remembered it, too. I can only surmise that the Redarc is keeping voltage consistently higher than before, so maybe the DC heating element works better. :h Still not as well as AC mode, but well within the safe zone for milk, meat, beer and ice cream (the four major food groups :B) The ambient temps the past few days have been in the low to mid 90’s, so the fridge is having to work to stay cool.

This is even better than I hoped from the 25 amp model. The 40 amp model was over $60 more, and I chickened out buying it. It’s nice ending a day of driving with the camper battery at 100% on the Trimetric, frosty beer, and ice cream that hasn’t gone soft. Before the Redarc, the beer and ice cream would be fine, but the battery would typically be at 80-85% depending on where the fridge was in it’s cooling cycle when we stopped.

Before the question is asked, I’ll just say that the fridge LP mode is unreliable while driving. Despite numerous attempts to fix its performance while driving, I haven’t been able to improve it enough to rely on it while driving. Sitting still, it’s perfect. The flame gets blown out often enough on the road that the fridge gradually gets warmer over the course of a day. I think it’s an issue with wind being able to come down the roof vent, because I’ve done everything possible down at the burner and the lower wall vent to keep the burner lit.

:):)

[MEXICOWANDERER]

Wisdom enables an individual to see the long-range consequences of their actions. In the case of the OP's charging situation, if the unit he purchases is well constructed it can be transferred from vehicle to vehicle.

At the moment I have to troubleshoot why my brand new Samsung S4 battery is discharging at 1% per minute after suffering a red-hot recharge. Typical new age fragility...

[pnichols]

David .... actually I fibbed a bit in my post immediately above yours.

I know exactly what's missing - and it's at a level above even common sense and it's been around to a greater or lesser extent as long as the hills of Australia - but way more rare nowadays.

It's Wisdom (IMHO, of course).

[MEXICOWANDERER]

It's called COMMON SENSE...
It's to see Albert Einstein talk when I was seven and here magic words "Imagination Is More Important Than Knowledge"

It's knowing when brand new must-have fashion is a recycle of 11 years ago.
It's knowing when gigantic car manufacturers spend millions of dollars evaluating life-span of components versus exclusivity of replacement parts sourcing and the profit.

It's knowing the component recycling makes for far less profit. Look at the motherboard of any PC and tell me component substitution is not cost effective.

It's being aware of the fact that the USA's crude oil production is close to surpassing the high of 1970 with one exception. We now have ultra light grade crude that produces 8x more light ends than heavy West Texas Intermediate even with use of catalytic cracking. Yet the oil industry cries OPEC! Oil spike pricing! Saudi Arabia! Shortages! Russia! Iran! This is a real Jim Varney national showcase of Forrest Gumpism.

Yes I am obsolete. No one cares about how things work. Bad? Throw it out. Try sixteen different inferior variant clones before giving up and saying "That's Life" Why do brand name made-in-Europe (flagship) medicines cost 1/15th the price in Mexico?

Why are Wiha screwdrivers better than Snap-On at half the price with German labor costing twice as much?

And Foggy Bottom failed-lawyers have a drug sedated public mesmerized with the word "computer -SMART- -Genius- -IQ- -Automatic- -Set And Forget- -One Touch-

If a cash register does not register "Change Due" you have as much chance as a fart in a whirlwind that the cashier knows how to figure change from the bottom up without using a calculator.

People who are as you put it -dumbed down- pnichols, haven't got a CLUE as to go about troubleshooting. From their bank balance to how much time is left on a parking meter.

And I, me, MOI suffer for this every time I deal with Americans at my expense in the USA Professionals. Go to "PAIN DOCTOR" for hyaluronic acid injections to lubricate shoulder joints not a narcotic. Never heard of it they explained. It's been around 60 years. So they KNOWINGLY give me STEROIDS! A diabetic! I just took at 407 blood sugar reading (8 phone images for evidence) An Rx for an MRI. Where? I asked. They hadn't a clue. I told THEM Scripps hospital has MRI machines. They balked at FAXing an Rx to the hospital. The thought they could sleaze by having me drive 30 miles. This is insanity.

[pnichols]

Mex ... it get what your hinting at above.

Plain and simple ... it's the Dumbing Down of America (and maybe the rest of the world?) ... and I don't mean in an IQ sense.

There's plenty of IQ to go around and the advanced degrees that go with it, but the thing that's missing seems to be getting scarce as hen's teeth. What's missing is something else, and I'm still trying to put my finger on it.

Keep up the fight!

[MEXICOWANDERER]

Landy that is pure fustercluckspeak from your friendly Orwellian mouthpieces.

The raw and pure energy consumed in the battery recycling process ADDED to the energy needed to reconstruct raw material (including brand new petroleum used to make the battery case) is absurdly greater than minuscule watts that are probably never going to be saved by psychotic over-management and mistreatment by cannabis warped rationalization by younger generation engineers.

It is idiocy, pure and simple.

The only rational way I see around this is for folks fortunate enough to have the resources to purchase a new rig. Spend the money and opt for a separate 2nd charging system. But it doesn't stop there. The 2nd alternator needs to have it's misguided testosterone supply euniched. The voltage regulator cut out like a vile hunk of malignancy.

For a 5th wheel, a remote rectifier with a decent adjustable voltage regulator would be magic. A 270-ampere ND hairpin alternator connected to a remote rectifier 25 feet distant in a 5th wheel has the ability to saturate absorbsion charge SIX GC batteries. Two hours of vehicle charging would (BFL13) 40/90 fill those batteries. Know of a 270-ampere converter or battery charger? FORGET ALTERNATOR OVERHEATING! With the hood popped and using a remote voltage regulator and rectifier overheating is not in the playbook.

Somebody needs to get off their fat *** and develop a MOSFET rectifier rectification package for alternators. Sequential phase gate triggering...

But oh.....no.... Detroit, and the idiot swamp gang are enchanted with WINDOWS 20, version of alternator management.

A read a report that stated in a panic that our younger generation has lost an average of 15-17 points on the Wechsler IQ test average. My suspicion it is caused by a form of vegetation. The proof of the phenomenon is irrefutable.

Life by algorithm. It suits the mentality...