Renogy DC DC Charger w/ MPPT

[BagheeraTheLion]

@smoothJoey hahaha.. I hear you. I'm def not in my 20's anymore (when I was working at a shop) but this time round reminded me of one of the reasons I don't do it anymore regularly. The bigger prize for me in this situation was having my rig up and running. Not sure I'd want to do this on someone else's car at this point lol

 

[snoobler]

I can read a wiring diagram but I'm too old for the crawling around holding a penlight in my teeth.
If I was going to do that it would have to be a much bigger prize.

Same, but I have to add "too fat" for myself.

 

[Dlello2]

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?

Hey sir, did you ever get an answer to this? I have (2) 100ah Renogy batteries connected to this DCC50s with (4) 100W solar panels. Wondering if you were able to get an answer from Renogy on this? Did you end up getting this to work out?

 

[mainebluedave]

hi guys looking for advice on connecting dcdc50.
I am looking to install this to my ford transit van which has factory fitted dual 95 amp batteries under drivers seat { uk version } known as starter battery and aux battery. there is a battery isolator which cuts out all power if aux battery voltage drops conserving starter battery drain. all is working fine as this has tripped a few times if I have left van doors open with interior lights on and engine switched off. I just press reset switch to get electrics back on again. I wish to connect dcdc50 with two 110 amp leisure batteries for camper conversion.
which battery should i take the live input from.
Thanks in advance.
dave.

 

[NelsonB]

I'm a little nervous about warnings that I could overheat my conventional alternator (Ford E450, 155 amps) in trying to charge my LiFePO4 400ah battery. I have the 50 amp Renogy unit, btw. Other than installing an inline, battery-type on/off switch on the battery cable before the Renogy DC-DC unit (to manually allow me to give the alternator an occasional break), does anyone know of a way of installing a remote switch using small wire somehow in conjunction with the ignition-sensing port, etc.? I've seen that on YouTube for the 20 amp unit (RV with Tito). BTW, I do not yet have PV panels installed, so the battery will be getting the full 50 amps from the alternator. Thanks!!

 

[Steptoe]

Compact with a sturdy design, it was built tough for all conditions.

That part i find confusing.
The manual states it will not tolerate dust,heat or even splashed water.
They then go on to advise you to mount it under the hood or on the chassis rail where it is likly to encounter all three.

 

[mainebluedave]

hi guys looking for advice on connecting dcdc50.
I am looking to install this to my ford transit van which has factory fitted dual 95 amp batteries under drivers seat { uk version } known as starter battery and aux battery. there is a battery isolator which cuts out all power if aux battery voltage drops conserving starter battery drain. all is working fine as this has tripped a few times if I have left van doors open with interior lights on and engine switched off. I just press reset switch to get electrics back on again. I wish to connect dcdc50 with two 110 amp leisure batteries for camper conversion.
which battery should i take the live input from.
Thanks in advance.
dave.

will go for the trial and error approach....

 

[HaldorEE]

will go for the trial and error approach....

I would connect to the starter battery.

 

[HaldorEE]

The DC to DC charger provides the battery isolation function, and should be connected to the starter batteries.

I would get rid of the battery isolator and connect the Aux battery in parallel to the starter battery (assuming they are the same battery). If they are different battery types/specs then I would replace the aux battery with a duplicate of the starter battery. This will reduce the likely hood of having a dead starter battery.

When I bought my Ford E350 diesel I was surprised to find the starter batteries were 6 years old. Typical battery life here in Phoenix AZ is 2 to 3 years due to the brutal summer heat. Part of this is probably due to their location (not in the engine compartment), but part is also due to having 2 starter batteries. It takes a lot of current to start a diesel so double batteries is the way to go.

 

[samb]

Has anyone tried using a larger solar panel around 38-41 Open Circuit Voltage with the DCC50?

I'm looking at some ~350W ones which are way over voltage for the 25V max specified but wondering if I could put a cheap mttp in between to lower it to 24V. Would that work and would it be worth it? The reason wouldn't just connect that other mttp to the batteries is that they are lithiums so I need the low temp shutoff that the DCC50 provides. I may also just get the Victron 100/30 which has that but is a lot of extra money for a very small difference, or just accept the limitation and get a 200W panel.

Unfortunately I only really have space on my van roof for a single panel and this can be a big 350W one or a 200W one.. Weirdly the 350W ones are way cheaper so you see my dilemma!

Also was considering putting either manual shutoffs or some kind of relay system to switch between solar and alternator inputs so I can get full 50a from the solar when not driving, but guessing the 25V limit would still apply?

This is my first build so pretty noob!

 

[bodiepetro]

I've been using my Renogy DCDC MPPT 50A controller successfully in my rig setup for six months now with 4x 100ah LiPo4 batteries and a lead acid starter battery with 400watts of solar.

I recently upgraded to an electric water heater and wanted to experiment what would happen if I drained my lithium batteries to ensure my starter battery was actually isolated so I wouldn't be stranded anywhere.... Two days later lithium batteries drain to 12.5v and I go to start my rig to charge with alternator and the starter battery is dead! (11 volts!)

How is this possible with battery isolating I asked?

I've double checked all my wiring, and ensured it is hooked up correctly (six months no problem).

Called Renogy and they said if you drain your lithium batteries far enough your starter battery will try and charge your Lithium batteries WHAT??!? This completely negates the entire purpose of having battery isolation in my opinion!

I've run this experiment several more times with the same result; when my lithium batteries drop below 12.6 my starter battery is completely dead.

This doesn't seem right, can I install another isolator between my starter battery and the DCDC MPPT controller in order to avoid this unnecessary draining? Hopefully the starter battery still gets a top off from solar when voltage is over 13.2.

Has anyone else had this issue?

 

[cdvreede]

I've been using my Renogy DCDC MPPT 50A controller successfully in my rig setup for six months now with 4x 100ah LiPo4 batteries and a lead acid starter battery with 400watts of solar.

I recently upgraded to an electric water heater and wanted to experiment what would happen if I drained my lithium batteries to ensure my starter battery was actually isolated so I wouldn't be stranded anywhere.... Two days later lithium batteries drain to 12.5v and I go to start my rig to charge with alternator and the starter battery is dead! (11 volts!)

How is this possible with battery isolating I asked?

I've double checked all my wiring, and ensured it is hooked up correctly (six months no problem).

Called Renogy and they said if you drain your lithium batteries far enough your starter battery will try and charge your Lithium batteries WHAT??!? This completely negates the entire purpose of having battery isolation in my opinion!

I've run this experiment several more times with the same result; when my lithium batteries drop below 12.6 my starter battery is completely dead.

This doesn't seem right, can I install another isolator between my starter battery and the DCDC MPPT controller in order to avoid this unnecessary draining? Hopefully the starter battery still gets a top off from solar when voltage is over 13.2.

Has anyone else had this issue?

unfortunately your story confirms that I'm not that strange as I never rely on the insulation capabilities - especially as the manual states that the DCDC "will charge the starter battery if there is surplus solar power". Good old VSR or Ignition relay is what I use...

BTW well done to get a response out of Renogy Customer Service!

 

[Reed Cole]

Has anyone tried using a larger solar panel around 38-41 Open Circuit Voltage with the DCC50?

I'm looking at some ~350W ones which are way over voltage for the 25V max specified but wondering if I could put a cheap mttp in between to lower it to 24V. Would that work and would it be worth it? The reason wouldn't just connect that other mttp to the batteries is that they are lithiums so I need the low temp shutoff that the DCC50 provides. I may also just get the Victron 100/30 which has that but is a lot of extra money for a very small difference, or just accept the limitation and get a 200W panel.

Unfortunately I only really have space on my van roof for a single panel and this can be a big 350W one or a 200W one.. Weirdly the 350W ones are way cheaper so you see my dilemma!

Also was considering putting either manual shutoffs or some kind of relay system to switch between solar and alternator inputs so I can get full 50a from the solar when not driving, but guessing the 25V limit would still apply?

This is my first build so pretty noob!

You won't see 50A from a 350w panel, also if you aren't driving then why would you need to shut off the alternator inputs?

 

[samb]

You won't see 50A from a 350w panel, also if you aren't driving then why would you need to shut off the alternator inputs?

Ah very good point on not needing to shut off the alternator input! Yea I'd be expecting ~30a max from the solar I guess. Starting to think I may just use it as a 50a b2b and hook up a separate mttp.

 

[Reed Cole]

Ah very good point on not needing to shut off the alternator input! Yea I'd be expecting ~30a max from the solar I guess. Starting to think I may just use it as a 50a b2b and hook up a separate mttp.

It's probably worth it to be able to use a 350w panel.

 

[harley]

does anybody know if the Battery Voltage Sensor on the Renogy DCC50S should be connected to the vehicles starter battery or the house battery?

 

[Ranger1/75]

You could put a relay in the feed line from the solar panels, that would open (normally closed relay) when you turn on the ignition. This way with the engine running, you would get max charge from alts but with engine off, it would revert back to solar.

Chevymike, that would be awesome. I'm a novice. How would you wire up the relay?

 

[denpmt]

I had one of the early Renogy DCC50S units installed in my Transit van and it worked well for just over a year. Unfortunately, the negative terminal bolt sheared off and I was dreading contacting Renogy's customer support. It took a week for Renogy to get back to me however once they responded, I had a new unit within 3 days. I'm happy to see that the terminal design has been improved and that Renogy backs their products.

 

[Jon Axis 27.7]

View attachment 1841
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

This my be a dumb question but here it goes. I am just starting to build my system. I was planning on adding solar last. Do I need a DC-DC converter to charge house batteries if I don't have solar yet? Can't I just wire the alternator charging wire to my SOK's? Also, Doesn't the BMS prevent overcharging from the Alternator? Thank you

 

[Reed Cole]

This my be a dumb question but here it goes. I am just starting to build my system. I was planning on adding solar last. Do I need a DC-DC converter to charge house batteries if I don't have solar yet? Can't I just wire the alternator charging wire to my SOK's? Also, Doesn't the BMS prevent overcharging from the Alternator? Thank you

A DC-DC is the recommended method for charging LiFePo4 batteries from the alternator because it not only charges at the correct voltage but it also limits the current. The BMS will have an overvoltage protection but won't limit the current. Not limiting the current can be problematic because it can wear out your alternator quickly or possibly charge your batteries at too high a rate. It's possible it could work for you, you just need to make sure the voltages and current put out by the alternator will fit within acceptable parameters for your batteries. I would recommend a shunt based battery monitor for you battery bank and a clamp on amp meter to measure what the output of the alternator is.