Optimate vs Redarc vs CTEK DC to DC chargers

[ChasingOurTrunks]

Hi folks

Like the title says, what are the pros/cons of these three suppliers of DC to DC chargers? There’s folks in this community with way more knowledge than I and I’m hoping they can chime in. There is also a lot of old information on dual battery setups from before the days of these smart DC to DC chargers. I’m hoping users of the above three products will let us know how they are working and what the pros and cons of these are.


Optimate DC to DC charger: $116.99 CAD on Amazon:

OptiMATE DC to DC, TM-500, 12V Battery / DC supply to 12V Battery Charger, Battery Chargers - Amazon Canada

OptiMATE DC to DC, TM-500, 12V Battery / DC supply to 12V Battery Charger in Battery Chargers.

www.amazon.ca

At that price point it’s not too far off the solenoid only systems. I’m curious about real world use. Other options:


CTEK DC to DC charger. $377.99 CAD on amazon.ca:

CTEK (40-186) D250SA 5 Step Charger - 12V - 20, Battery Chargers - Amazon Canada

CTEK (40-186) D250SA 5 Step Charger - 12V - 20 in Battery Chargers.

www.amazon.ca

Does three times the price mean three times the performance/reliability?

And the $$$ option from Redarc at $573.55 CAD on amazon.ca:

REDARC BCDC1240D DC-DC CHARGER 12V40A OUT : Amazon.ca: Electronics

REDARC BCDC1240D DC-DC CHARGER 12V40A OUT : Amazon.ca: Electronics

www.amazon.ca

I believe National Luna may offer a similar kit but I am not familiar at all with it. How do the above compare? Do they all functionally do the same thing? What does the Redarc give me that the Optimate lacks?

 

[teotwaki]

What type and brand of battery will be used? Some need fairly high peak voltages such as the Odyssey brand.

The Optimate has a very low input current of 2.7 Amps so output charging current will be lower
My CTEK has been very good at keeping my Odyssey battery happy. Max current output is 20 Amps and the solar charger function is great
RedArcs are supposed to be very good and the model you listed can source 40 Amps for charging

 

[ChasingOurTrunks]

Thanks Teotwaki. That’s exactly the kind of info I was hoping for; As I’m still learning about these systems I don’t know what specs are most important so your answer is helpful.

In my application I’ll be using a deep cycle AGM battery for my house battery; it’s a Motomaster brand which is a store brand for Canadian Tire. Given my geography, this one made sense for warranty reasons as every mid sized city in Canada has a Canadian Tire.

It’s a Group Size 31, 1000 cranking amps, 105 amp hours, and 200 minutes reserve.

Do you (or anyone else reading) know how much amperage I would need for a battery like I’ve described? I know it’s not a straight forward situation of more necessarily being best as some batteries suck up a charge very well and are good for high amp chargers where others are a bit slower at absorbing charge so prefer a lower amperage. My understanding of all 3 products is that they adjust the output according to the detected battery type but of course, a max output is a hard limit so the CTEK is probably a better bet.

 

[dreadlocks]

Renology makes one: https://www.amazon.com/Renogy-Battery-Batteries-Multi-stage-Charging/dp/B07Q4SVX3M

The benefit of these is you can pamper your house batteries for more lifespan and charge them properly instead of relying on the vehicle's rather dumb charger.. your starter battery is never really discharged much and is pretty easy to get a decent lifespan out of em (up to 10y for those in southern states).. your house batteries are going to be regularly cycled deeply and to get them charged properly, quickly and safely its best to give them proper bulk/absorb/float cycles for that bank, independent of the rest of vehicle.. Its really important for AGM batteries because they need to be pampered to keep them happy, plus it provides isolation from the starter battery and sometimes even a built in solar charger.

however, there's alot going for just getting cheap batteries, abusing the crap out of em and replacing em when they let go.. you can usually get alot farther with less money over time as buying expensive batteries, top of the line chargers, and still struggling to get them to last much longer can really start adding up over the decades.. IMO AGM's are garbage, especially if you buy some no name like a tire store brand..

Charging a 100AH AGM with a 20A charger is like 15min slower than a 40A charger.. 20A is good charge rate for that size AGM.

 

[ChasingOurTrunks]

Thanks Dreadlocks. That’s great info and I am grateful.

As for the AGMs being garbage I’ve read that the performance gains do not equate to the price, and when they decide to give up they just go without warning. My reason for selecting a deep cycle AGM was more focused on the sealed battery/no maintenance/no leaks at angles than on any particular performance advantage of charge or discharge. I wanted to have as much flexibility as possible in mounting it up and didn’t want to have to be checking water levels and such. Still, it was a $300 sting so I’ll have to see for next time as I may go in a different direction. That’s why I want to spend a bit more on putting in a smart charging system as from what I’ve read and what you describe, the charging system with a Smart charger is a lot more flexible for various battery types so if I want to go with a different house battery later on I can.

Also I know it sounds like I bought a no name from a tire store but Canadian Tire is one of our countries largest retailers — Like Sears, but with higher quality stuff and a heavy focus on the typical Canadian lifestyle. They have great warranties on their kit and their batteries are very well regarded here in Canada. 3 year full replacement warranty, 5 year prorated coverage, and Canadian Tire stores are literally all over the country, even in our most remote small cities. For the next few years our adventures will be mostly domestic so this gives us a bit of peace of mind to test out other parts of the system without being too far from a cheap/free replacement if need be.

Thanks for the info on charging rates — it seems like the extra cash on the higher amperage would be a waste of money. Are there other battery types that DO need the 40 amp charging that you know of and thus would make spending on he higher capacity worthwhile?

 

[dreadlocks]

Only the top of the line AGM's provide promised benefits and are truly deep cycle.. such as Lifeline or Surrette/Rolls and then the costs are hardly worth those benefits.. but if you have to mount it sideways or something then AGM does have that over FLA.. unless your putting very high charge/discharge loads a cheap FLA battery wont need water checked but once or twice a year.. and thats just to be safe when you winterize it and put it on a charger for months on end.. people worry about hydrogen emissions indoors or acid getting everywhere with FLA, but apparently auto manufacturers dont worry that much because my FLA battery is located under the drivers seat and my car has never exploded from gas buildup and neither is there a bunch of spilt acid eating my seat away so those concerns are largely blown out of proportion, especially with the low discharge/charge rates overlanders/boondockers typically use.

There's no such thing as a Maintenance Free Battery, all batteries need care and maintenance if you want em to last.. if you ignore a lead battery, dont matter if its SLA or FLA it will crap out on you quickly.

A multi-battery bank such as 2 or more AGM's, or 4 or more FLA's could use 40A charging rate.. or something like LiFePo4 that loves to charge at high rates.

 

[ChasingOurTrunks]

That’s fantastic info thanks dreadlocks! I likely won’t be going for a bank of batteries so a 20 amp should do me fine.

I also really appreciate the info on other battery types and will be revisiting that info when my current battery craps out on me. It seems that with batteries it could be useless in 2 years or it could last a decade depending on use and care but inevitably at some point I will need to replace it.

Thanks again!

 

[shade]

apparently auto manufacturers dont worry that much because my FLA battery is located under the drivers seat and my car has never exploded from gas buildup

That's probably a vented enclosure.

Explosions from lighting off hydrogen may not be that common, but it's a real risk. If the OP is mounting a battery in an enclosed space, vented battery boxes are cheap insurance against it.

 

[dreadlocks]

its vented into the cabin, just sitting in a plastic box under my seat.. it does have a regulated charger that keeps it from overcharging the thing.

 

[PSea]

If the charger uses dip switches for charging profiles, avoid it. Go with something fully programmable. Sterling Pro is excellent. Will work should you upgrade to LiFePo as well.

If you don't believe me about dip switches, call a few AGM manufacturers and ask them for their recommended charging profiles. Many deviate and a dip switch isn't going to do it. If you live in warmer climates, temp compensation is important too. Sterling does this as well.

Whatever u do, DO NOT put the charger in the battery box. Even AGM can gas.

I'll be putting one of these in mine. Good luck.

 

[vtsoundman]

Hi folks

Like the title says, what are the pros/cons of these three suppliers of DC to DC chargers? There’s folks in this community with way more knowledge than I and I’m hoping they can chime in. There is also a lot of old information on dual battery setups from before the days of these smart DC to DC chargers. I’m hoping users of the above three products will let us know how they are working and what the pros and cons of these are.


Optimate DC to DC charger: $116.99 CAD on Amazon:

OptiMATE DC to DC, TM-500, 12V Battery / DC supply to 12V Battery Charger, Battery Chargers - Amazon Canada

OptiMATE DC to DC, TM-500, 12V Battery / DC supply to 12V Battery Charger in Battery Chargers.

www.amazon.ca

At that price point it’s not too far off the solenoid only systems. I’m curious about real world use. Other options:


CTEK DC to DC charger. $377.99 CAD on amazon.ca:

CTEK (40-186) D250SA 5 Step Charger - 12V - 20, Battery Chargers - Amazon Canada

CTEK (40-186) D250SA 5 Step Charger - 12V - 20 in Battery Chargers.

www.amazon.ca

Does three times the price mean three times the performance/reliability?

And the $$$ option from Redarc at $573.55 CAD on amazon.ca:

REDARC BCDC1240D DC-DC CHARGER 12V40A OUT : Amazon.ca: Electronics

REDARC BCDC1240D DC-DC CHARGER 12V40A OUT : Amazon.ca: Electronics

www.amazon.ca

I believe National Luna may offer a similar kit but I am not familiar at all with it. How do the above compare? Do they all functionally do the same thing? What does the Redarc give me that the Optimate lacks?

CTEK as a straight DC charger (from alternator) does a good job. As a solar MPPT controller, I am not a fan. Some time ago, I did some side by side comparisons with a Victron unit - the CTEK took longer by a surprising amount. I don't recall at this point the amount. If you look at some of my older posts on the CTEK unit you'll find my info. During solar MPPT, the unit sweeps too frequently / pulses the battery. CTEK uses an overly complicated charging algorithm (unnecessarily so). Doing it all over again, I'd ditch the CTEK unit as it is expensive B2DC unit and a 2nd rate MPPT controller.

 

[vtsoundman]

If the charger uses dip switches for charging profiles, avoid it. Go with something fully programmable. Sterling Pro is excellent. Will work should you upgrade to LiFePo as well.

If you don't believe me about dip switches, call a few AGM manufacturers and ask them for their recommended charging profiles. Many deviate and a dip switch isn't going to do it. If you live in warmer climates, temp compensation is important too. Sterling does this as well.

Whatever u do, DO NOT put the charger in the battery box. Even AGM can gas.

I'll be putting one of these in mine. Good luck.

There is a lot of internet mythology regarding AGMs and VRLA batteries. Auto mfrs have been putting AGMs and VRLA batteries in passenger compartments for years. My Sprinter has one beneath my feet.

Any commmercial residential UPS whether it be an APC unit or Belkin, has both the VRLA, charger (and all other associated electronics) within a frogs hair of each other for years - no fires. Just don't seal the battery box and use an AGM and VRLA and you'll be fine.

If truly concerned, put the battery in its own box and run a vent tube outside.

A decent AGM from Sam's Club (100ah Duracell @ 180$ or so) or hell, even Universal Power Group from amazon will last a good long while if properly cared for....and you can replace them 2-3x before getting near the cost of a high end battery.

Unless you're going to be off grid full time or relying on the batteries for your income, Sam's Club works great. I rely on Sam's Club and UniVersal Power group in my Jeep and Van for work/income and play. I use them hard (many cycles with DoD > 50%)...been fine for last several years.