I just got done with my setup with the Renogy DCC50S.
Short-term review of the Renogy DCC50S:
It’s nice that it’s all integrated with alternator charging [DC/DC] (Max 25A IIRC), + Solar [MPPT] (Max 25A IIRC). Simple install and works with most battery types. Big perks are there’s no need for battery isolators and when the house battery is fully charged, it’ll trickle charger the starter battery if ya got solar.
If your looking for simple and room for growth, this is it. Other manufacture to look at are Redarc and CTEK.
House battery wise, i opted for a 100aH LiFePO4 by SOK with integrated heater and bluetooth. Great value at $600 with quality components that’s serviceable. I ski and winter camp so I wanted to make sure I could charge the house battery in low temps. AGM’s are great because you don’t have to worry about low temp conditions, but you’re limited to only using 50% of the capacity before you sacrifice the health of the battery
Here’s some pictures of my setup. Don’t mind the mess, I’ll get around to tidying it up later.
I have the “fancy” victron bluetooth dc/dc charge controller. What’s nice with that is I can actually open the victron app when driving to see how much juice it’s adding.
The one thing I’ll mention is that not only do you have to size your wires correctly, there’s a very, very small gauge sensor wire you have to hook up to something that tells the dc/dc charge controller that your vehicle is actually running. For me that was easy because my sPOD’s switch box was right by truck camper electric box in the truck bed. But I did have that brief panic attack where I thought it was defective until I looked at the wiring diagram again and noticed I forgot to connect that sensor wire to the dc/dc controller and an ignition active circuit. It’s easy to miss in the diagram if you don’t read the instructions. I added the red text and arrow.
Thanks all for the info and responses. I have set up a house battery with isolator in other vehicles before and based on the battery tech I’m planning right now sounds like that might be the simplest and most economical option.
I like the options and flexibility of some of the high end options like the Redarc but am trying to use what I already have around as much as possible to keep it budget friendly.
I think a DC-DC charger is better than an isolator ever for an AGM.
I’ve had the renogy setup working flawlessly for a couple years now. It does have an AGM specific output, multi-phase charging, and will charge the house battery at a higher voltage than the ALT is putting out if needed.
As mentioned, It also works great with solar and trickle charges the starting battery when the house if full. Both my batteries are 100% charged quickly on any day with a little sun.
It also futureproofs you if you decide to switch to lithium down the road. My previous vehicle had a basic isolater setup and I was constantly killing house batteries because it never charged it properly.
Spend the extra money for a DCDC charger and skip the isolator. Faster charger on AGM, keeps alternator healthy, and keeps battery healthy with multi-stage charging algorithms. Plus, if you do ever upgrade to a different battery type, no need to buy a DCDC charger or modify the wiring (I spent more on wiring then my DCDC charger).
One item people fail to consider is the alternator and the amount of output to all of your electrical uses. Usually not a big problem, but if you’re running multiple batteries, lighting systems, radio, amps, etc., you may want to review this and check the box that all is good. The OEM alternators did not account for all of the add ons we’re doing these days. Just something to consider.
This is where @Taco-Surfer important note comes into play. How I sized mine was by finding out the continuous current available from my Alternator. From there, I could see that I had room for the size charger that would make sense in my application. In my case, I had ample room to add a 40A charger. In hindsight I could’ve gone with a smaller 20A which would suffice in my case.
The key is making sure you leave some headroom on the alternator; then fuse/breaker out your DC/DC connection accordingly. I started with a 100A; but since I opted to connect my winch to the same fuse I learned quickly that it draws alot. So don’t do that.
I was too lazy to get your truck specs; but a quick google search for a mid 2000’s tacoma is as follows:
How many amps is a Tacoma alternator?
Performance
Mounting Type
Direct fit to OEM Mounting
Hot Idle Amperage @ 200F
170
Max Amperage
270
Hot Max Amperage @ 200F
240
Positive Output Stud Size
8MM x 1.25 Copper
So personally in your case I would go for a 20A if you’re charging a 100aH battery. That should give your alternator some headroom so it’s not working its but off when running/charging
The other thing to keep in mind, once you figure out how much headroom your alternator has as @dignon pointed out, is your charging needs.
I only have a 100AH house battery. Assuming I drained that all the way down, which I never do, I could charge that back to full in 4 hours with the 25A redarc system that I went with. If you had a 300AH house battery that you planned to drain 100% on a regular basis then you would probably want to be able to charge that at a higher rate and would want a higher throughput system.
Battery type comes into play a little bit there as well. I’ve got lithium and I know lithium can charge at very high amperages( c-rate ). A quick google search shows that AGM can handle much less and this might then be your limiting factor on what size DC-DC charger you get. If your battery can only charge at 10 - 15 amps then there’s obviously no need for the 50A charger.
Check out my battery heater thread I have going too. I’m in the process of troubleshooting a solution to get my Self Heater to trigger on Shore power. Turning out to be much more complicated that just hooking up a charger.
