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diy solar

Renogy DC DC Charger w/ MPPT

Hi - I'm trying to figure out how I want to wire up my truck for a camping battery in the bed. (At the moment I use a goal zero 400Wh battery, charging it either in the cab (cigarette lighter) or via 100W portable solar panel) and have some questions.

1. Is there any strong reason to prefer installing this unit in the engine bay vs waterproof box I already have in my rack? I guess it saves me having to run an IGN signal wire.

2. I think an alternative would be to use separate dcdc and mppt chargers. Renogy has a 40A dcdc charger, whereas I think this unit will only draw 25A from the alternator. I think I can then just run a separate low amperage MPPT charger in parallel, i.e. they can both be "on" and connected to the camping battery at the same time?

3. Is there any strong reason to prefer using this unit over separates (pro - simplified wiring, less space, minus - if I have to run the truck to recharge (cloudy days...), significantly longer run time).

Sorry for the dumb 101 type questions.
 
RandyP said:
Depends on the solar panels you may already have, or plan to buy. If those panels were intended to charge a 12v battery system, the 25v max solar voltage is just right if you wire them in parallel.
Click to expand...
I should have said, if the panels were designed to charge a 12v battery bank, 25v max solar will work if you wire the panels in parallel, not series. Panels designed to charge a 12v battery bank are generally rated at less than or equal to 25v open circuit voltage.
 
I just returned a DCC50s-G1 to Renogy. I have a 24 volt 300 watt panel on my van and it works very well with a Victron MPPT charge controller to charge my 12v 400ah AGM battery bank. It takes the 29-34 volts from the panel and reduces it to 13.4-14.5 volts when charging. I (mistakenly) assumed that the Renogy DCC50 would do the same. When I got it I checked all the specs. I somhow had missed that it had a 25 volt limit on the solar input. I checked with Renogy tech support and they confirmed the limit. I noticed that the stand alone Renogy MPPT controllers do not have such a low input voltage and should work like the Victron. Live and learn.
 
Update on my charger. I sent it in to be tested. It was found to be defective and they are sending me a new one. I also got this email yesterday claiming that the first run of this model was deemed not up to standards. So anyone with the serial number seen below can exchange it for a new one free of charge.

Renogy Inc
2775 E Philadelphia St
Ontario CA 91761

Replacement Exchange
RBC50D1S-G1


January 27, 2020



Dear Valued Customers:


Renogy is fully committed to manufacturing reliable and quality products to the highest of standards. A recent company audit has identified that a few DCC50S 12V 50A DC-DC ON-BOARD BATTERY CHARGER WITH MPPT with SKU: RBC50D1S-G1 did not comply to our standards. At no expense to our valued customers, we would like to exchange the RBC50D1S-G1 for a unit that meets our highest of standards. We believe this action is consistent with our ongoing commitment customer satisfaction.


We have identified the following barcode located on top of the product and should begin with the following:

19210-XXXXXXX
attachment



If you have any questions, or need further information, please contact us at 1-909-287-7111. We apologize for any inconvenience this situation may have caused and want to reassure you that Renogy is always taking the necessary steps to ensure our product quality meets your expectation.

If you wish to participate in the replacement exchange, please respond to this email and a customer service representative will be able to assist you in the exchange.


Sincerely,


(Appointing Authority)




Signature Date

Angelica Vargas
Customer Service Representative
2775 E. Philadelphia Street
Ontario, CA 91761
1-800-330-8678


111515:756525
 
I realy like this device. It would be ideal for my rental RVs. I would like to use REC 320 watt solar panels. They have a nominal voltage of 40 volts. Is it possible to use a step down DC to DC converter to bring the voltage down to 24 volts so I would be able to use this MPPT charger? Let me know if that is a feasible option.
 
Guys recently some comments have appeared on Wills original review video suggesting the unit reduces alternator charging from 50A to 25A if any Solar input is detected!
This sounds crazy to me and absolutely not what I would expect to happen as it would be counter productive
Has anybody validated the claims or seen it documented by Renogy?

Thanks
 
Alexank said:
Guys recently some comments have appeared on Wills original review video suggesting the unit reduces alternator charging from 50A to 25A if any Solar input is detected!
This sounds crazy to me and absolutely not what I would expect to happen as it would be counter productive
Has anybody validated the claims or seen it documented by Renogy?

Thanks
Click to expand...
Dont know much about these systems, but can it not be run as a stand alone, without the solar being hooked up to it?
Just a pity they dont have a 12v to 48v version or better still a 12v - 12/24/48v selectable version. There is a monster market for alternator charging, for whomever gets it right and reliable....imo.
 
The manual does say that any solar input reduces the alternator charging to 25A. You can download the manual from their site.
 
lmwilco1 said:
The manual does say that any solar input reduces the alternator charging to 25A. You can download the manual from their site.
Click to expand...
Yes after posting the question I went through the manual and it is referenced in section 3.3
If it works as it sounds like it does that is stupidly disappointing because for example when driving with near zero solar input but just enough voltage to register as something i.e dusk or overcast and heavy rain etc its only going to charge from the alternator at 50% of max.

That's just plain Dumb!

I will have to fit a solar disconnect relay operated with the ignition on which really ought not to be necessary.
 
I was under the impression it was to preserve the battery life or some such. (As with some Fords putting out power that could cook some batteries?)
Does it change depending what battery chemistry you have it set for?

I seem to recall in Will's video on this, that he said solar could be added later.
 
Remy1927 said:
Update on my charger. I sent it in to be tested. It was found to be defective and they are sending me a new one. I also got this email yesterday claiming that the first run of this model was deemed not up to standards. So anyone with the serial number seen below can exchange it for a new one free of charge.

Renogy Inc
2775 E Philadelphia St
Ontario CA 91761
Click to expand...

Congratulations on the free exchange, I'm sure that solved your problems including the broken stud.

I'll see if my unit falls in the recall group and consider exchanging it. At this point it works as advertised and I am happy with it.
 
Top of the line batteries. Has a ring to it. But which line ?
 
bikenanigans said:
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:

www.altestore.com

Sizing MPPT Charge Controllers and Temperature | altE DIY Solar Blog

Learn how to size an MPPT solar charge controller for a solar panels system and learn the trick for taking into account temperature.
www.altestore.com www.altestore.com
Click to expand...
A bit late to the party, but.....
The other thing to consider, are the panels flat on a roof of a van etc or tilted towards the sun.....if flat, then they would be unlikely to produce max power.
 
Last edited:
I sent an email to Renogy asking if a lithium battery disconnects itself due to low temperature what impact having solar panels connected will have, here is their reply:

Thank you for contacting Renogy. There can be an issue with leaving the panels connected without a battery connected as well. Your panels will continue to send power to the dcc and without any place for the unit to send the power it is receiving, can overheat and melt over time. Please let me know if you have any additional questions.

So I guess this means if you have a low temp disconnect on your charging circuit you also need to disconnect the solar panels.
 
lmwilco1 said:
I sent an email to Renogy asking if a lithium battery disconnects itself due to low temperature what impact having solar panels connected will have, here is their reply:

Thank you for contacting Renogy. There can be an issue with leaving the panels connected without a battery connected as well. Your panels will continue to send power to the dcc and without any place for the unit to send the power it is receiving, can overheat and melt over time. Please let me know if you have any additional questions.

So I guess this means if you have a low temp disconnect on your charging circuit you also need to disconnect the solar panels.
Click to expand...
Wouldn't it send some power to the starting battery? IIRC, once the house battery is full, it sends power to the starting battery. I wonder if it reading the house battery at zero volts, stops that function?
 
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