Renogy DC DC Charger w/ MPPT

Will Prowse

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Finally reviewed it! People asked me repeatedly, and I was too busy with the solar shed. For the last few days, I tested it like crazy..

And I love it! I should have tested it months ago. Works extremely well, and it's fool proof. I pushed it to every limit, and if it cut off, it would restart a few seconds later.

Dead simple and easy to install for beginners. I really wish I had one of these when I was first adding solar to my RV. Super cheap too, compared to buying a voltage sensitive dc/dc charger and 50 amp mppt. Only downside is solar input voltage is extremely low, so 12v panels need to have branch adapter.

Key features (copied and pasted from renogy):
  • Designed to charge service batteries from two DC inputs—solar panels and alternator.
  • Built-in Maximum Power Point Tracking (MPPT) to maximize the solar power.
  • 3-phase charging profile (Bulk, Boost, and Float) ensures your service battery will be accurately charged at the correct voltage levels to 100%.
  • Built-in Voltage Sensitive Relay (VSR) for easy setup with traditional alternators.
  • Compatible with smart alternators (with variable output voltage).
  • Trickle charges the starting battery via solar panels if the service battery is fully charged.
  • Isolation of the starting battery and the service battery.
  • Temperature and voltage compensation features prolong battery life and improve system performance.
  • Smart Protection Features: battery isolation, over-voltage protection, battery temperature protection, over-current protection, overheat protection, reverse current protection, solar panel and alternator reverse polarity protection.
  • Compatible with multiple battery types: AGM, GEL, Flooded, and Lithium.
  • Compact with a sturdy design, it was built tough for all conditions.

I love it so much, that I created a new solar power package on my website! Dead simple blueprint:

Click here for parts list and schematics
 

Ped

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Nov 4, 2019
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Its good they came out with a better current range for the alternator side as 20a is low and 40a might tax a stock alternator. But really meeds to be at least 30a/30a. Or just higher on mppt side.

As well annoying that it doesnt use the rover bluetooth at that price point.
 

toverb

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Sep 25, 2019
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I really want to use this charger for my LFP bank keeping lead acid for the starter battery to secure the alternator. But I don't want to charge the LFP batteries to more than 13.8 V and stop charging when they reach that level. I don't want any float charging for the LFP's.
Can I do that with this charger?
 

dirk

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Sep 21, 2019
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Just a thought: could you swap out the car part of this out to say a windgenerator? If so I could see something like this being used for for example a fixed wireless relaystation, a forest service observation tower or a small lighthouse.
 

Rider

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I really want to use this charger for my LFP bank keeping lead acid for the starter battery to secure the alternator. But I don't want to charge the LFP batteries to more than 13.8 V and stop charging when they reach that level. I don't want any float charging for the LFP's.
Can I do that with this charger?
Probably a question for Renogy. Drop them a line...
 

Keith_PDX

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@Will Prowse Can you override the auto-sense alternator auto-on and use the Switched ignition input and the unit only uses that? It looks like there's terminal's for it. There is a decent amount of people that use switched input to control charging through their BMV-712 for low temp, etc...or to disable alternator charging and just use solar.
 

israndy

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Oct 13, 2019
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I see it has the RJ45 connector on it, does that mean it works with their Bluetooth communication module? What's it display when it's running on that unit? Is it custom for the DC-DC or does it use the same display as when it's plugged into a solar charger?
 

mjpalm21

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Nov 13, 2019
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Charging from Alternator and solar panels, plus, is there any option for adding AC charging capability?
It will be the ultimate solution for my RV.

This would be perfect for me as well if it supported shore power.

I would think you could use an inverter like this that has automatic transfer to shore power and built in battery charging. You could connect the inverter's battery charger to a relay that switched it with the alternator input to the Renogy.

Any thoughts on this config?
 

Ped

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Why the relay? If youre on shore power youre not running the engine. Even if you ran a genset while going down the highway on a sunny day you can have 3 charge sources going at once. All you need to do is have the renogy and the inverter charger for all 3 sources.

If you dont need the inverter portion a converter will do the same for battery charging.
 

Airstreamer

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Nov 17, 2019
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I'm building a van with 3x100 Ah Battleborn batteries and 600w solar. Thinking of adding this unit for charging.

Thing is, I often remove the batteries to swap them to a travel trailer that I also own. I was hoping that this could trickle charge the starting battery when I did that. But... the manual says you have to have a battery connected. In this scenario, does anyone see an issue adding a small lawnmower type 12v battery in place of the Battleborns? Seems that would do the trick. Or am I missing something? (Yes, I would change the charge profile)
 

mjpalm21

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Why the relay? If youre on shore power youre not running the engine. Even if you ran a genset while going down the highway on a sunny day you can have 3 charge sources going at once. All you need to do is have the renogy and the inverter charger for all 3 sources.

If you dont need the inverter portion a converter will do the same for battery charging.

Just to prevent having an issue if the engine was started while on shore power.
 

clos8

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Nov 17, 2019
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I had it in my cart, procrastinated, and now you review it and they are Gone!!! hahahha. oh well hope they get more soon. I also asked them about a unit with more DC voltage input from solar, they told me there was a lot of demand and it will most likely come, but nothing being developed at the moment.
 

shadzee

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Nov 20, 2019
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@Will Prowse
Hi Will, thanks for the review. I have a suggestion to follow up the review

... Long story... ;-)

- I have a Van
- For various reasons I decided for all-in-one solution
- I chose the GoalZero Yeti 3000
- GoalZero 12v regulator (works fantastically)
- 300 watts of solar - Renogy panels
- GoalZero "Car Link" connections to the Van's battery ($500) , their solution for DC-DC charging
(the system output is great, powering the fridge, induction cooktop, TV, computers, USBs, lights...)

"Car Link" is supposed to draw as much as 50 Amps from the van's battery and charge the Yeti. However, it barely draws 10 Amps. Charging a 3000WHr battery at 100-150 watts does NOT really work ;-(

"Car Link" also is plugged in place of MPPT controller (there is only one external attachment port) that comes with the Yeti 3000, so the solar panels are now plugged in to the slower controller. ;-(

Suggestion;
You already have a Yeti 1400, and the Renogy DC-DC charger.

- Can we use the Renogy DC-DC charger as an external solar MPPT controller?
- Can we use the Renogy DC-DC charger as an external charger, and feed the Yeti through the TOP external Port? (BIG question mark ;-)
- OR... can we combine the out put of DC-DC charger and the solar controller into a thick wire and plug it into the Yeti's Anderson input?

This way we can replace the expensive $500 (and always back ordered) GZ "Car Link" with a $200 Renogy with better throughput ?

An all-in-one Lithium (with 12v regulator if needed) and this Renogy DC-DC charger could be a great solution for most Vans and smaller RV's. Much cheaper and smaller AND Safer than DIY solutions.

thanks.
 
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bikenanigans

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Nov 23, 2019
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Can someone confirm my thinking here?

I’m looking at these 200W Hightec panels on eBay which were $320 for two panels yesterday, currently $370:


They’re listed as having 24.335Voc which seems to be just under the 25V limit listed in the manual for this new Renogy unit. Am I correct in thinking two of these can be safely used in parallel with this setup? Everyone seems to be going with four 100W panels but for a number of reasons (space, wiring, etc) I’d rather go with two 200W panels if it works.
 

bikenanigans

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Nov 23, 2019
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I sent Renogy an email with my question and here’s what they had to say:

Thank you for contacting Renogy, these panels marginally make the cut which means that in colder conditions when the voltage goes up, you may not have this unit working with solar. This is something to consider, otherwise the application would work fine.


I honestly didn’t know that was a thing, although it makes sense. Here’s a link I found explaining it more for anyone interested:

 
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