RandyP
Solar Enthusiast
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I think the install/user manual says 25A max.
Renogy DC DC Charger w/ MPPT
- Thread starter Will Prowse
- Start date
dirt diggler
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Not seen that much yet lol
When it first engauges the reverse DC charge it puts out 4A then it drops to a steady 2A BUT my starter battery was full so i loaded it up (turned lights on) and it poped up to 9A before the house battery started loosing voltage and it cut off, basicly i ran out of solar to keep the house battery voltage up and supply the starter battery (only have 400W and it was late afternoon in the UK).
I expect it will supply more when i have more solar (mid day ect), it reacted to the load on the starter battery within 2 seconds, a lower state of charge starter battery would do the same as the load i think ?
Very happy with this unit and have the 50a version for past 6 months. After reading all the alternator side of things, went out to the caravan to test. Have a smart alternator. Isolated the solar input and with no sense wire attached, the unit delivers a 25amp charge (24.93v), then again with sense wire inline, the charger does what it is supposed to do and straight up to 50a charge. So it appears to me the programming sets a 25a limit without sense wire which is easy to understand however when both Solar and Alternator are tested, that comment in the manual on solar having the priority to appears to support something more than a 50/50 split given a further limiting of alternator current yet again as I get 25a solar limit then a 16a alternator (down from 25a). Have 720 solar so inputting more than the 25a at the time. It’s that reduction in alternator current combined with solar that has me stumped.
dirt diggler
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It's good to hear somone else having posative results with this unit
not just me then LOLI don't have smart alt and had very similar results with and without the sense wire conected depending on how low the house battery is, obv the more charged it is the lower the Amps the DCC will let in IME throttling the Alt before throttling solar, if i turn a lot of loads on on the house battery the alt ramps up to cope IF the solar is already maxed out (i only have 400W)
Pardon me if this question has been asked, but can I run a 50DCS with only the PV connected? I plan to incorporate the alternator charging later, but for now would like to get up and running with MPPT first.
To rephrase: If I connect to the MPPT input but ignore the alt input will the unit operate as a regular MPPT charger? Thanks!
To rephrase: If I connect to the MPPT input but ignore the alt input will the unit operate as a regular MPPT charger? Thanks!
No problem. Works good.
Sskeeter
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I added a 300Ah lithium battery to our 21 Northstar 850sc camper and a BMV-712 Victron battery monitor. I hooked up the truck to the 7way connector, revved it up, and as suspected saw very little current coming in via the bluetooth app as suspected.
Next step is to install the Renogy DC-DC with MPPT charger. Space is very limited so I'm planning to build a 13x20 wood shelf over the battery to accommodate the charger and maybe an inverter in the future. On this model there is no vent and hole for the battery so I'm thinking I can run the truck cables through the cable tv inlet (not ever planning on using it) and put an Anderson connector here for quick disconnect.
The solar part seems pretty straightforward. Planning on mounting two Renogy Flexible Solar Panel 175 Watt in parallel and following the existing wire chase above the fridge. Will mount with this method for added airflow and removal if needed - https://www.rvwithtito.com/articles/install-flexible-solar-panel-rv/
Any feedback appreciated.
Next step is to install the Renogy DC-DC with MPPT charger. Space is very limited so I'm planning to build a 13x20 wood shelf over the battery to accommodate the charger and maybe an inverter in the future. On this model there is no vent and hole for the battery so I'm thinking I can run the truck cables through the cable tv inlet (not ever planning on using it) and put an Anderson connector here for quick disconnect.
The solar part seems pretty straightforward. Planning on mounting two Renogy Flexible Solar Panel 175 Watt in parallel and following the existing wire chase above the fridge. Will mount with this method for added airflow and removal if needed - https://www.rvwithtito.com/articles/install-flexible-solar-panel-rv/
Any feedback appreciated.
Been working the last little while to get my Renogy 50A DC2DC charger working well and I think I finally got it tonight.
2 main issues I was facing.. Maybe obvious to most but alas.....
1 - Heat, the sucker runs HOT. With 200W of solar hooked up to it running in a warm trailer (77F ambient)I am hitting a 120F in the device. Once over 140F it starts throttling power. So add in some DC charging and it quickly starts throttling. Even from cold, just a few minutes at 50A it will start throttling.
2 - The Ign sense cable.. It tricked me.. When I first hooked it up to my 2019 F150 I did not use the IGN cable. It pegged 50A and I though great I don't need it... Well I have since learned more about these smart alternators... I tried just hooked the Sense wire to 12V near the DC2DC charger but this never seemed to work well. I did some testing the last couple days and now have it hard wired to the 7 pin power connecter.
To combine both 1 and 2 together I also hooked a fan into the 7 pin connecter. So when I start the truck (Ford you have to also put it in drive before the charge power goes down the 7 pin) it kicks on the fan and the DC2DC charger. As soon as I turn off the truck the fan stops and the Charging stops.
So far so good. 2 Week trip planned next week so we will find out.
So for yourself I would recommend to be mindful of these 2 hurdles. Heat is an issue... And you may also need to run a IGN wire if you have a smart alternator.
Sskeeter
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Thanks!
Hey guys! I'm setting up a system using the 30A Dual Input DC-DC/MPPT Charger and was curious about wiring in a disconnect switch for the solar array. It's my understanding that most MPPT controllers have a dedicated terminal for the PV (+) and (-), however these units have the (-) going to a common negative also for the house battery and starter battery/chassis. I know that ideally the disconnect switch for the solar array should be dual pole and switch both the (+) and (-) wires. In the case of these dual input chargers, should only the (+) wire be switched since the (-) wire goes to the common negative?
Alexank
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@Spire
You still have two wires from the panels to terminate so nothing to stop you using a dual pole switch if you want too.
I personally never ever use dual pole switches. so don't worry about it too much an isolator in just the +PV feed will work perfectly ok.
That can be as complicated or as simple as you like, via a switch or a relay with a remote switch or a relay operate from the D+ feed or even by using a pull out fuse. The later using a Maxi Fuse holder provides fusing and isolation all in one!
You still have two wires from the panels to terminate so nothing to stop you using a dual pole switch if you want too.
I personally never ever use dual pole switches. so don't worry about it too much an isolator in just the +PV feed will work perfectly ok.
That can be as complicated or as simple as you like, via a switch or a relay with a remote switch or a relay operate from the D+ feed or even by using a pull out fuse. The later using a Maxi Fuse holder provides fusing and isolation all in one!
Thanks for the help.
I actually have a spare Blue Sea 300A battery switch I was thinking of using. I've read that these shouldn't be used because they're only rated for 48V, and solar arrays can output a lot more than that. I'm using two 100W panels in parallel, and the open circuit voltage of each panel is 24.3V. Since this is the case, I'm thinking it would be OK to use. Am I missing something here?
Sskeeter
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I put a disconnect on the solar positive so I can turn it off and get the full 50amps when I drive. Works well. Sounds like what you have will work.
You can get a DIN mountable 2P breaker for under $20. Makes things nice and safe. I got away from using Fuses and have a small DIN rail with a few breakers on for everything. Much neater, less room and safer I believe.
DC 250V Circuit Breaker,2P DIN Rail Mount Low-voltage Miniature Circuit Breaker,Solar Panels Grid System Electric Cut Off Switch(40A) : Amazon.ca: Tools & Home Improvement
DC 250V Circuit Breaker,2P DIN Rail Mount Low-voltage Miniature Circuit Breaker,Solar Panels Grid System Electric Cut Off Switch(40A) : Amazon.ca: Tools & Home Improvement
www.amazon.ca
rubberlegs
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- Nov 28, 2022
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I notice in this how-to by Will Prowse: https://www.mobile-solarpower.com/simplified-400-watt-fewer-wires-and-alternator-charging.html that he recommends the 50A. But later on he says to get the 30A Renogy dual charge controller instead, because of some solar wires that can't take the high amperage. And his link to purchase goes to the 30A version.
I only need 200A solar (am getting by fine with 90W, but thinking about upgrading for cloudy weather). I'm gonna switch from AGM to Lithium and thus looking at the Renogy DCC30S or 50S. Our truck has been wired with 10 AWG and it looks like I might get away with that wiring with the 30A. But rewiring isn't super complicated.
Anyway, I was leaning towards the 50A, but the link points to the 30A... I'm really waffling on which one to get.
I only need 200A solar (am getting by fine with 90W, but thinking about upgrading for cloudy weather). I'm gonna switch from AGM to Lithium and thus looking at the Renogy DCC30S or 50S. Our truck has been wired with 10 AWG and it looks like I might get away with that wiring with the 30A. But rewiring isn't super complicated.
Anyway, I was leaning towards the 50A, but the link points to the 30A... I'm really waffling on which one to get.
boondox
Chief Engineer, RedNeckTech Industries
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Disagree that it means nothing and is all mental! This a time honored practice among conservative engineers called "de-rating". A fine practice and one I believe in myself. Electronics that run cooler last longer.
EnsignR
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- Sep 25, 2022
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I've a question about this DC-DC charger, and I'm sorry if its already been asked and answered before, but there's over 40 pages in this thread.
Can you connect a AC-DC charger to the inputs of this so it can be used from charging/battery management?
I'd like to attach an old laptop or battery charger or something similar, and use it to not only charge the battery, but also power the 12V system while shore power is available. Is this possible? (I realise you'd probably have to pull D+ high??)
Thanks
Can you connect a AC-DC charger to the inputs of this so it can be used from charging/battery management?
I'd like to attach an old laptop or battery charger or something similar, and use it to not only charge the battery, but also power the 12V system while shore power is available. Is this possible? (I realise you'd probably have to pull D+ high??)
Thanks
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