Renogy 50a dc dc mppt charging profile w/engine on

[davesupreme]

i watched will's excellent video, but he only fed 5amps from the solar side on his demonstration. i'm trying to wrap my head around what happens when you're getting full amps (more than 25) from the solar side?? the manual states it can handle 660watts solar, so if you're running down the road in Utah at high noon, does it take all the amperage from the solar, and then cut down on the alternator side, or is it always a 50/50 split, 25a/25a, when the alternator is charging ?? in that case, alot of that solar capability is lost w/the alternator/engine running ? i even called Renogy, and the guy seemed to indicate this 50/50 split, so ..... i guess the 660watts would be good to give the 50amps when the engine is off ??? i'm just trying to figure out the charging priorities and how they work? seems all i read here that this gizmo is not that popular ? so what could i use instead to be able to use both alternator and solar on my new 350 Transit ?

 

[justoneguy]

I'm not a big fan of renogy, but I have to say that my dc 50 has worked perfectly for 2 1/2 years..
It outputs 50amps MAX, solar OR alternator.
Or Up TO 25 amps each from both at once
If solar is producing any power at all,
The alternator is limited to 25 amps.

 

[davesupreme]

thanks for the reply !!!
ya, the 25/25 is what i'm seeing everywhere .....
i guess their 660w solar max would only be good if the engine is off .....
what happens to that max solar juice when the alternator is charging ?? heat ???
does that gizmo get really hot then ?? so that mounting it on the outside of the van compartment would be a better thing ??
i gotta lotta ????? .....

 

[MisterSandals]

what happens to that max solar juice when the alternator is charging ?? heat ???

The DCC pulls the power it needs/wants, so it does not need to dissipate anything as heat.

 

[justoneguy]

That max solar juice is just hypothetical.
If it's not being used (and it's not)
It's not being generated.
I've got my dc50 hidden behind a wall where it doesn't get any ventilation, and it hasn't failed

 

[mega5]

If it gets any voltage from both sources then it goes into "50%+50%" mode. If you want manual control to override this, you can use breakers to force it to only take one of the input sources.

So for example if its really cloudy and the solar is only making useless amperage, you could flip your solar breakers to disable that input and pull the full amperage from the alternator instead. At night it will make full amps from the alternator because PV voltage is zero.

I have never really worried about manually controlling it.

Its a lesser known but very good product. Using discrete victron components (Orion+MPPT) would cost $500 while the renogy is only about $200

 

[davesupreme]

that's an excellent idea !! i'm trying to wrap my head around all this, and you guy's are really helping!

so u think 400w of solar panels would be good for this and a 206ah SOK battery, or would 600w be better in the long run.
i'm trying to figure out a rack now......

 

[MisterSandals]

so u think 400w of solar panels would be good for this and a 206ah SOK battery, or would 600w be better in the long run.
i'm trying to figure out a rack now......

This mostly depends on your daily Wh usage but lets mess with numbers:

206Ah x 13.2V = 2719Wh

2719Wh / 400W solar = 6.8h to fully recharge (more than a day, even without any loads)

2719Wh / 600W solar = 4.5h (maybe barely enough during simmer with 5h solar but woefully inadequate in the winter with maybe 3h solar)

 

[davesupreme]

all i'm figuring now is just an Iceco refrigerator, so i ain't using much yet, but ..... i'm sure i'll figure out more as it goes along .... i really don't want an inverter ..... tho' i'm dreaming about one of those 12v AC's for the roof. maybe just a fan to start out with ..... definitely wanna camp w/this rig .... i like dirtbikes, and i'm about to sell out and hit the road ....

 

[fratermus]

does it take all the amperage from the solar, and then cut down on the alternator side, or is it always a 50/50 split, 25a/25a, when the alternator is charging ?? i

This is the most-misunderstood aspect of the charger. The dispositive section of the manual:

seems all i read here that this gizmo is not that popular ?

I'd guess it's the most popular DC-DC/MPPT combo since its release. It has one significant limitation (25v PV input) and a couple useful features rare in other units of this type (low temp cutoff in Li profile, battery voltage sensing option).


It is great sport here on the forum to bash Renogy, which IMO says more about the bashers than it does about Renogy. All the Renogy gear I've had hands on, including the DSCC50S, worked as designed.

Before Renogy the Ctek setup was the most popular. The Kisae is gaining mindshare. I imagine Redarc dominates in Australia. SRNE has released a 50A that looks promising; like the Kisae but with mixed solar/alt modes, voltage sense wire terminal, and a terminal that accepts a signal to stop charging - the latter could be used with a temp switch to disable charging in cold weather.

so what could i use instead to be able to use both alternator and solar on my new 350 Transit ?

There are many combo units out there, but it's probably more common to use separate solar charge controller and alternator-based chargers. More control, typically better spect, not a single point of failure.

mounting it on the outside of the van compartment would be a better thing ??

I don't know what a van compartment is. Chargers like this are typically mounted as close to the battery bank as possible; consult the manual for specifics.

so u think 400w of solar panels would be good for this and a 206ah SOK battery, or would 600w be better in the long run.

This depends on your daily power requirements, when/where you are camping (solar harvest varies greatly by season and location), and how many hours you drive on average per day. I will say it is rare for people to wish they had less panel.

 

[davesupreme]

ya, those manual instructions are what was confusing me .... so in a perfect world, if 600w of PV is putting out 50a and the motor/alternator is running, the Renogy disregards the alternator side and just uses the PV ? if the PV's are below what the SOK LiPo wants, then the alternator side kicks in to the tune of 25/25a, or a max of 25a from the alternator and whatever is there from the PV's ?...... in Will's video, he was feeding 25a from the alternator side, and 5a from the PV side .... it would have been nice to see the reverse, or just max 50a from the PV side to see the change ..... mega5's idea of controlling this w/breakers is interesting .... thanks for the help

 

[Tony S]

Very interesting. I'll be keeping up with this thread.

I don't want to hijack this thread in any way!
I hope my question(s) and idea could help others interested in this DC to DC MPPT and how I would like to use.

IF this unit can do it - I have 2 alternators on my Rig and don't plan to have the MPPT connected in ANY way to the vehicle electrical system or its batteries. IF Possible.

I would like to use this MPPT to be able to connect my 2nd alternator and some roof mounted solar panels to the PV charging port on a Bluetti Max200.

With hopes of it switching between the two and me not having to remember to manually switch.

Below was my idea before I saw Will's video on this MPPT charge controller. I'm still not 100% sure it can work for my application.
I wanted to come up with an automatic transfer switch controlled by a relay or something.
The default of the relay, controlling the transfer switch, would be the panels and it would switch to alternator charging circuit when the engine is running.

 

[Tony S]

that's an excellent idea !! i'm trying to wrap my head around all this, and you guy's are really helping!

so u think 400w of solar panels would be good for this and a 206ah SOK battery, or would 600w be better in the long run.
i'm trying to figure out a rack now......

I recall, Will talking about sticking with 400W of panels so you don't have to up size the wiring and you can use some kind of connectors. (Sorry forgot what they were called.)

 

[davesupreme]

ya, they got 4-way connectors to run the PV parallel, but they don't got 6-way, i don't think ??? ..... i think you gotta go 2x 3-way, then 2 to 1 to get it all parallel .....

 

[MisterSandals]

i think you gotta go 2x 3-way, then 2 to 1 to get it all parallel .....

Uggg.
The MC4 connectors handle 30A max. What is panel Isc?

6P panels require all 6 panels to be fused. Not terrible with inline MC4 fuses.

 

[fratermus]

so in a perfect world, if 600w of PV is putting out 50a and the motor/alternator is running, the Renogy disregards the alternator side and just uses the PV ?

Since the example is bumping into the output limit It might be more useful to consider a situation where the solar side can make 40A. If demand is ≤40A the solar carries it alone whether or not the vehicle is running. If demand is >40A then the alternator would help when the vehicle is running. So If demand were 44A it would be a 22A+22A split.

 

[EnsignR]

I've got my dc50 hidden behind a wall where it doesn't get any ventilation, and it hasn't failed

This is exactly the kind of information I'm looking for. We/I have one in a box waiting me me to figure out how - mostly where - to install it. The manual says it needs a ridiculous amount of clearance top and bottom which is excluding it from all the places I'd like to put it. If it doesn't get that hot then I guess I can ignore their recommendations and put the device with it's beefy heat sink under the seat where I want to and provide some ventilation??

 

[EnsignR]

I imagine Redarc dominates in Australia.

Not at the prices they charge here (I suspect). The 40A Redarc is about 2.5 times the price of the 50A Renogy (though I'm not sure its limited to the 25A+25A like the Renogy is, but still)

ps. I love the quote in your signature

 

[ready2rvdude]

This mostly depends on your daily Wh usage but lets mess with numbers:

206Ah x 13.2V = 2719Wh

2719Wh / 400W solar = 6.8h to fully recharge (more than a day, even without any loads)

2719Wh / 600W solar = 4.5h (maybe barely enough during simmer with 5h solar but woefully inadequate in the winter with maybe 3h solar)

Help me figure out alternator charging large lipoe4 banks & what device to connect to alternator b+ terminal.

It seems using a high amp alternator could charge batteries within a few hours of idling without the noise of a generator for city boondock co
Camping

 

[MisterSandals]

Help me figure out alternator charging large lipoe4 banks & what device to connect to alternator b+ terminal.

Ok but you should start a new thread to keep your issues separated from this thread. Feel free to tag me so I see your thread. You will need to describe your system and indicate what you intend to do. What battery do you have?