Redarc vs Ctek

GSP

New member
#1
Im looking for some feed back on why I should go one way or the other. This set up will be in a 2017 Power Wagon with 100ah agm "house battery". I'll also be adding ac/dc charging. I love the idea of the Redarc Manager 15 or 30, but they dont offer it for 110volt....yet....
 

DiploStrat

Expedition Leader
#2
First question, do you really need a DC-DC charger? The odds are good that your Power Wagon already charges at the correct voltage. Check that first. You may be able to get away with a simple switch, key controlled relay, or intelligent relay.

If you really NEED a DC-DC charger:

-- Sterling has a wider range of units with greater user control of the settings.

-- REDARC has simpler units, but they may be smaller and offer more flexibility in mounting, e.g. under the hood.


In any case, the limitation is likely to be charging time, so consider adding solar and a good shore charger.
 

DiploStrat

Expedition Leader
#5
I believe the Redarc has a built in solar controller. It is also setup for lithium batteries.
I use the built in solar controller, but it should be noted that the total output of the charger does not change, all that changes is the source of the charge. That is, the REDARC favors solar over alternator. If you want to increase the total current available, then you will need a separate solar controller.
 
#6
i am actually in this dilemma right now aswell, i am building a 4x4 Van and was in between the Ctek 250DA + Smart Pass, Redarc Manager30, Samson Evo. the reason i am only looking at these 3 is because i want an integrated charge controller that can take care of AC/DC/Shore power instead of having 3 separate charge controllers and dealing with them confusing each other at the battery.

i think i am going for the Manager 30 because it integrates all 3 seemlessly, comes with everything to manage 3 charge sources and monitor you battery system. If I hook up the solar panels, B2B, and shore and if they all could supply power at the same time (really unlikely, most likely 2 at once i.e solar/B2B while moving or Solar/Shore while stationary if plug-in available) then the Manager30 would distribute distribute power to charge from all 3. i have seen scenarios where the shore or B2B and solar at the same time from separate systems will trick themselves and then both go to float or standby regardless of actual battery voltage.

you should note this is for a decent electrical system:

350ah of house battery
diesel heater for winter camping
fridge
lights
laptop/phone charging
fans

the system if all my estimates are correct should last 3.4 days in the Winter and 5.4 days in the Summer before i reach my DOD limit with no charging.

Here are a few questions for you:
  • Why do you need 110v power? what appliances do you want to run that need it?
  • What are your goals for the vehicle (i.e boondocking, remote camping, campsite use, etc.)? im guessing its a power wagon with a camper on the back?
  • Whats the daily load for the 100ah battery bank?
  • Will you be around shore power alot?
from these we should be able to help you better determine if you need to spend all that money on the manger 30 or if you have other options that are priced better.
 
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#7
i am actually in this dilemma right now aswell, i am building a 4x4 Van and was in between the Ctek 250DA + Smart Pass, Redarc Manager30, Samson Evo. the reason i am only looking at these 3 is because i want an integrated charge controller that can take care of AC/DC/Shore power instead of having 3 separate charge controllers and dealing with them confusing each other at the battery.
Not really an issue; they won't. This assumes of course, that each charger is set correctly. The CTEK, with the SmartPass will give you a higher charge rate, but, depending on your voltages, you might be better off with a relay (I like the Blue Sea ACR) and properly sized wires. This plus you choice of solar and shore chargers.

Why do you need 110v power? what appliances do you want to run that need it?
In my case, induction cooktop, toaster, Nespresso machine, and microwave. With a big fridge, Webasto Dual top, cameras, phones, laptops, etc. maximum overnight draw is about 150 Ah, more typically, 125 Ah. Depends on weather, and how much you cook breakfast. YMMV.

A 30A charger is going to take on the order of six hours to recharge 100Ah into a lead acid battery. So I would want a larger charger.
 
#8
Not really an issue; they won't. This assumes of course, that each charger is set correctly. The CTEK, with the SmartPass will give you a higher charge rate, but, depending on your voltages, you might be better off with a relay (I like the Blue Sea ACR) and properly sized wires. This plus you choice of solar and shore chargers.



In my case, induction cooktop, toaster, Nespresso machine, and microwave. With a big fridge, Webasto Dual top, cameras, phones, laptops, etc. maximum overnight draw is about 150 Ah, more typically, 125 Ah. Depends on weather, and how much you cook breakfast. YMMV.

A 30A charger is going to take on the order of six hours to recharge 100Ah into a lead acid battery. So I would want a larger charger.
I was mainly asking the OP, since he is the one with the question. But I would have to say your math is wrong. From 100% discharge a 30A battery charger will take 3.3 hrs to charge a 100Ah battery to full throw in another 10% and you are at 3.67hrs total.

Now my 350 ah battery will take on the order of 11-12 hrs to charge from 100% discharge to full.

But beside that you need to know how much battery capacity you will use per day. In my case it's roughly 50Ah in the summer and 83Ah in the winter. The 350 Ah comes from wanting to beable to stay off-grid with zero charging for 3 days (worst case when we camp in the mountains during ski season). And you also depending on your battery won't want to discharge below 50-80% of you battery, so you need to look at the depth or discharge curve for the battery you choose. In my case I get 850 cycles if I do 80% DOD which is fine for me.

Also in your case Diplo you should be looking at the discharge limits of you battery bank as well. So you do not pull more then it is capable of supplying.

Just my 2 cents!
 

DiploStrat

Expedition Leader
#9
You are most welcome to your own opinions; my numbers are based on years of real world living with a 600 Ah AGM battery bank. This actually covers two different vehicles, two different charging setups but the same size battery banks and basically the same appliances.

With an AGM battery down to about 50%, you will typically see your charger hit full output for about 30 minutes to an hour. There after, as the battery voltage rises, the charger output drops, usually by about 50% every hour or so. Then you need to consider absorb charge time, see page 20 here: http://lifelinebatteries.com/wp-content/uploads/2015/12/6-0101-Rev-E-Lifeline-Technical-Manual.pdf

YMMV. But you may want to ask some of the folks who have been living with big AGM banks for their experience.

N.B. I have a 40A REDARC BCDC 1240, so, in the case of my second vehicle, my observations are based on the performance of a REDARC product. (Also have a decent battery monitor to keep an eye on what is happening.
 
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#10
But I would have to say your math is wrong. From 100% discharge a 30A battery charger will take 3.3 hrs to charge a 100Ah battery to full throw in another 10% and you are at 3.67hrs total.

Now my 350 ah battery will take on the order of 11-12 hrs to charge from 100% discharge to full.
your math is flawed.. there aint no 100aH traditional lead based battery that will charge from 50% discharge to full in 3.3h, regardless of your charger.. your looking at 3h of just absorb charging the last 20%.. and if your discharging to 100% its unlikely its going to fully recharge ever again, especially AGM chemistry... in my experience it took about 6h+ to recharge a 100AH AGM w/a 40A charger from 50% discharge, and the battery never took much more than 20A even though the charger was capable of much more.. was not really that much faster than my 10A charger because how little time it was charging above 10A.

now my 100AH Lithium battery w/nearly 100% efficiency and takes full charge output to nearly full, that charges up from about 5% charge to 100% charge in ~4h with 30A charge current.. in the real world and not a calculator.
 
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#11
I can give some real world experience using both a voltage sensing relay and a Ctek DC-DC charger. I have Nissan Frontier and initially I just ran 4 gauge wire with a relay and that seemed fine at first but I soon realized that it was never fully charging the AGM 100ah battery I had in the back. After research this seems to be the common scenario if you are trying to charge a lead acid deep cycle battery just using your alternator. I would only use a VSR/relay type setup with a car type battery being used for things like lights, winches, exc.

I got the Ctek 250S DC-DC charger and it has worked like a charm. Easy setup and instructions. I also have solar hooked up to it which has worked well. When the house battery is charged the solar begins charging the truck battery to keep it topped off.
 

DiploStrat

Expedition Leader
#12
I can give some real world experience using both a voltage sensing relay and a Ctek DC-DC charger. I have Nissan Frontier and initially I just ran 4 gauge wire with a relay and that seemed fine at first but I soon realized that it was never fully charging the AGM 100ah battery I had in the back. After research this seems to be the common scenario if you are trying to charge a lead acid deep cycle battery just using your alternator. I would only use a VSR/relay type setup with a car type battery being used for things like lights, winches, exc.

I got the Ctek 250S DC-DC charger and it has worked like a charm. Easy setup and instructions. I also have solar hooked up to it which has worked well. When the house battery is charged the solar begins charging the truck battery to keep it topped off.
Depends on the vehicle, or more properly, the voltage of the charging system. I used an intelligent relay on a 2013 Chevrolet and it had no problem charging a 600 Ah AGM battery. The limitation was driving time, not voltage.

Can't comment on Nissan, but many vehicles top out at 13.9v, in which case a battery to battery charger, like the CTEK, REDARC, Sterling, et al., would make all the difference in the world. Hence my original comment to the original poster.
 
#13
Depends on the vehicle, or more properly, the voltage of the charging system. I used an intelligent relay on a 2013 Chevrolet and it had no problem charging a 600 Ah AGM battery. The limitation was driving time, not voltage.

Can't comment on Nissan, but many vehicles top out at 13.9v, in which case a battery to battery charger, like the CTEK, REDARC, Sterling, et al., would make all the difference in the world. Hence my original comment to the original poster.
Absolutely. It just generally seems that most vehicles are not reaching a voltage that is conducive to efficient and effective charging of a deep cycle. You have/had a 600ah 12v battery in your vehicle? I have no doubt a vehicles alternator will charge that over enough time, but my goodness, that sure is a big battery. You put that thing in your vehicle with a small crane?
 

DiploStrat

Expedition Leader
#14
... I have no doubt a vehicles alternator will charge that over enough time, but my goodness, that sure is a big battery. You put that thing in your vehicle with a small crane?
No crane, four 300 Ah 6v batteries. ;)

In my case, 250A of alternators and typically 135Ah of discharge. This meant that the initial charge rate was about 100A, dropping by about 1/2 about every 1/2 hour. Typically spent at lot of time between 25 and 50A max charge.

Also, 500w of solar, which would give up to 25A of charge. The limiting factor was the voltage rise of the batteries themselves.

Hence my comments about real world performance.


My new truck as a 24v system with a 12v camper bank, hence the REDARC. The 40A is great, but I miss that first hour or so at the higher amperage.
 
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