HELP:Renogy DCDC50A Draining Starter Battery

[Whytey]

I just got my solar/2nd battery all installed and hooked up in my 4runner. I have a Snomaster 12v fridge installed. I got it setup and ran my fridge overnight on May 17th and throughout the day on May 18th. On the evening of May 18th I checked on the system and found that my starter battery was below 11v. I disconnected my starter battery from the Renogy DCDC50A controller and it immediately went back up to high 11v’s (still dangerously low). So obviously there was a draw on my starter battery from the Renogy controller. Fridge was still running and 2nd battery still had good voltage.
What could be causing this draw from the starter?
The vehicle is a 2007 Toyota 4Runner so it is a traditional alternator. I did NOT connect the Renogy IGN wire (required for smart alternators). The DCDC controller manual states for a traditional alternator it will disconnect the starter batter at 12.7V as to not drain it.

Any ideas what might be causing this drain?
I still have some testing to do after work but the only thing that changed recently was the addition of this solar setup.

My setup is as follows:

Starter Battery: Northstar 100AH AGM Battery
House Battery: Renogy 100AH Lithium w/ Self Heating
Solar Controller/DCDC Charger: Renogy DCDC50A
Solar Panel: Renogy 175w Flexible Solar Panel
Inverter: Renogy 1000w Inverter
Fuse Panel: Blue Sea Fuse Box
Circuit Breakers: Blue Sea Circuit Breakers (assorted sizes)

And here is a diagram of the wiring setup I created:



Any help would be appreciated. I am wondering if the controller is faulty, or if it is “stuck” on smart alternator mode as the cut off for tat is in the 11.5V range I believe.

 

[Dicko]

I believe the IGN wire should be used. The IGN wire is not concerned with battery or alternator type. It just wakes up the dcdc charger to operate when the igntion is on ONLY. yOUR DCDC CHARGER IS CURRENTLY WORKING ALL THE TIME.

 

[Whytey]

I believe the IGN wire should be used. The IGN wire is not concerned with battery or alternator type. It just wakes up the dcdc charger to operate when the igntion is on ONLY. yOUR DCDC CHARGER IS CURRENTLY WORKING ALL THE TIME.

The manual for this controller states that the IGN wire is not to be connected if using a traditional alternator though.

 

[Dicko]

I would charge both batteries up to 100% state of charge and then turn on the dcdc charger with the fridge running. Monitor the start battery and see if it gets below , say 12.5. If it does then that would mean the dcdc is not turning off when it gets below 12.7. I see what you mean about the IGN wire. I dont see how connecting would hurt. It appears that the dcdc has a built in voltage sensor relay to cut in at 12.7. My 40amp dcdc renogy is about 18 months old and it definately allows the IGN wire to be connected...actually it must be connected or the dcdc will drain the start battery...therefore I,m assuming the vsr in your renogy is not operating correctly.

 

[TacomaJoe]

I vote for charging the starter battery and giving the setup another test. This time watch the LEDs to determine what the controller thinks its doing. The IGN wire seems odd to me, but that's what the manual says.

Dicko, on yours, if the IGN wire is not connected I wouldn't think it would drain the battery. When the IGN goes to +12VDC when you start the vehicle, it should then start the charging.

 

[Dicko]

No mate. My Renogy 40 dcdc states that the IGN must be connected...Insert from the manual..

 

[TacomaJoe]

Dicko, your 40A DC-DC and my 20A DC-DC manuals say the same thing, but I looked at the manual for his and it is different. I haven't gotten my wires pulled from the truck battery to the back of the truck, so I'm working on theory only. His seems to measure the source battery rather than use the D+ wire.

 

[Dicko]

I reckon his will have a voltage sensing relay of some type. His model says that the current flow will stop once the start battery gets down to 12.7..i.e..alternator should always be charging over 12.7 ( smart alternator can sometimes drop below this...this is why some people leave their air con or lights on to keep the alternator pushing out more voltage to keep up with these higher power using users. My money will be on a faulty vsr in the unit...assuming everything in the system is wired correctly and batteries/alternator are in good shape. . I,m glad I have the IGN model becaus e I know for sure that the dcdc will not pull power when I turn the car off and walk away.

 

[dirt diggler]

Not much help i know if you meen the DCC50S ? (as in the pic) i have mine wired up without the ign wire no issues at all so i suspect a faulty unit ?
Had it wired like this for a year and it keeps the starter batterys topped up just fine (as well as the house bat OBV)

 

[Borderpatrol]

Hi, new here but just set up a similar system for my 21 ranger and teardrop camper. Couple questions, were you parked in your example or driving? If parked, Why would you leave your truck connected to the camper when parked? I always unhook. Also are you running a dedicated line from your starter battery to your dc dc or hooked to your 7pin 12v power? I have a dedicated line 6g to an Anderson plug at back of truck then to the Renogy dc dc. 60 amp fuse at starter battery. I’m using the 7pin 12v source as my ignition sensor. ( not sure if this is recommended) I read somewhere that even with a non smart alternator the ign sensor should be connected. I have yet to run this system. But when hooked up in my drive way the battery was pulling.48amps from my truck, so seemed to work.
I still have some more experimenting to do in mine but I think a simple fix for you would be to disconnect power when parked. Just something I’ve always done for some reason. Your trailer should not pull from the truck unless the alt is running. So removing their connecTed when not needed would isolate the starter battery.

 

[Whytey]

To clarify, this setup is actually installed in my Toyota 4Runner so no trailer here.
The DCDC controller is mounted in the back cargo area.
I could disconnect the starter battery when I park however that defeats part of the purpose of purchasing this unit. When the vehicle is parked and solar is charging the 2nd battery, when that battery reaches 100% the Renogy controller will actually trickle charge my starter battery. So that additional feature is awesome on paper.

I charged up both batteries to full and tried to recreate the issue but could not. I went out camping this past weekend and when I got to camp I left everything connected. After a few hours I went and checked on it and my starter battery was again dipping down into the 11 volts range. I disconnected the the starter battery then reconnected it. And since then it has worked fine. It almost seems like when I park the vehicle the 12.7v cutoff doesn’t activate. But if the vehicle battery is below the 12.7v and I disconnect and then reconnect it it all works fine.


However,
Since this weekend I have left the setup duly connected and the fridge running and I have NOT been able to recreate the issue. It’s disconcerting as I can’t address and fix the issue if I can’t find the issue…

I still haven’t heard back from my email to Renogy CS so I will be following up with a phone call whenever I can find time.
The only other factor I can think of is I have a Bluetooth battery monitor that is installed on my starter battery and that is what I am taking these readings off.
I have compared with my meter and they are within .05v of each other. But I haven’t been able to check the battery itself with my meter when it is reading in the 11ms or even 10v range.
But i am doubtful that this is the issue because the Renogy DC Home app with the BT2 monitor was also displaying a warning that my starter battery was over discharged…

Hopefully it’s as simple as a faulty unit but I’m having a tough time diagnosing the issue as it’s working fine at the moment.
Not a big issue if this happens in my driveway but it kills my starter battery when I’m out in the words then that’s a big issue.

 

[12VoltInstalls]

The manual for this controller states that the IGN wire is not to be connected if using a traditional alternator though.

Am I wrong to say that maybe the manual has a misprint?

If the ignit sense is connected it would seem security to not discharge the starting battery. I would trust that over the 12.7V ethereal automagic setting that clearly once failed to function.

 

[Whytey]

Am I wrong to say that maybe the manual has a misprint?

If the ignit sense is connected it would seem security to not discharge the starting battery. I would trust that over the 12.7V ethereal automagic setting that clearly once failed to function.

I am very hesitant to connect the IGN wire as it looks like it would definitely cause me some issues.
The cutoff voltage for a smart alternator is 11.5V and it starts charging at 12V.
This would definitely over discharge my starter battery.

I have had the system connected and running for over a week now with the vehicle barely being driven so the solar is handling everything and it has all been working as it should…

Maybe some gremlins right out of the box but I will definitely be keeping an eye on it.

 

[12VoltInstalls]

would definitely over discharge my starter battery

Your alternator doesn’t charge to 13.8V?!

 

[Whytey]

Your alternator doesn’t charge to 13.8V?!

It does. It charges around 14.5V

But this chart shows that if I had the IGN wire attached that it would charge off my alternator/starter battery at >12V and then would disconnect when it got to <11.5V. Which is way too low.

Without the IGN wire in (as I have it set up) is it would start charging off the alternator/starter battery at >13.2V and then cut off at <12.7V

 

[12VoltInstalls]

this chart shows that if I had the IGN wire attached that it would charge off my alternator/starter battery

Ignition sense normally disconnects a charger when ignit is off so it won’t discharge the starter battery.

Without the IGN wire in (as I have it set up) is it would start charging off the alternator/starter battery at >13.2V and then cut off at <12.7V

Am I obsolete or geriatric?
Those numbers are all completely backwards to me.

 

[Whytey]

Ignition sense normally disconnects a charger when ignit is off so it won’t discharge the starter battery.



Am I obsolete or geriatric?
Those numbers are all completely backwards to me.

I agree the numbers do seem strange for the smart alternator.
The numbers look good for the traditional alternator (no IGN wire). If I turn the truck off as soon as I battery gets down to 12.7V (which would be fairly quick) then it disconnects.

The smart alternator numbers do seem strange to me because even if a smart alternator is connected it’s still likely a traditional battery and if a lead acid battery or AGM was drained down to 11.5V that would be damaging. So I agree with you that those second numbers seem strange.

 

[12VoltInstalls]

If I turn the truck off as soon as I battery gets down to 12.7V (which would be fairly quick) then it disconnects.

That is wacked. I wouldn’t use a device designed to discharge my starting battery by 20%. I’d use a relay and solenoid to immediately disconnect when ignition is shut off.

That Renogy sounds like an engineer was doing mushrooms. Totally backwards. A DC2DC charger should shut down so the starting battery isn’t depleted ever

 

[Dicko]

I cut and pasted from another thread posted 6th May...


Update with respect to my previous post regarding the DCC50s hardly charging at all from alternator.
Connecting the IGN (ignition sense) wire made all the difference in the world. Despite the alternator outputting below 13.5V, the charge current now goes up to 50A as it should. Disconnected the IGN sense wire and the charge current is down to maybe 6A.
Bottom line: if you have a non-smart charger and the DCC50s does not charge adequately, connecting the ignition sense wire helps.
Note: this is in direct violation of the installation instructions. Do this at your own risk.






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