Renogy DC/DC converter draining starter batteries

[SVLupine]

I have a Renogy DCC1212-20 converter installed to charge my 800Ah Lithium bank from the alternators that charge my 2 starter batteries which are FPV M24-700st 560cca,700mca 105rc. I have two engines with Traditional 35amp alternators with a BlueSea 5511E switch between the starters/alternators and batteries. I usually run one engine at a time so I have a switch to power on the DC/DC converter when underway. The converter is draining both my starter batteries somehow and I’m not sure why.
I’ve included a wiring diagram that shows how I have it set up. The switch has a combine feature that can isolate each battery/starter or combine to form one bank from the two. I’ve been running the switch on combine so the alternator that is running would charge both start batteries and then the house when they are full. It appeared to be working based on the app that shows current going into the house bank, but keeps draining the start batteries. It should stop charging if the batteries drop below 12.7v. The other thing I noticed is that the 30amp input fuse turned brown but didn’t blow.
1. Can anyone tell from my wiring diagram if the wiring is set up weird? Did I create a problem using the bluesea switch how I did ?
2. I did run both engines and didn’t think to turn the DC/DC off – Could running both 35amp alternators have damaged the unit?
3. The manual calls for ANL fuses but I wasn’t able to get one when I installed it and was advised that a standard auto ATO or maxi fuse would be fine. Not sure if the fuse choice is contributing to the problem or not.
4. I’ve reached out to Renogy about the issue but haven’t gotten a response yet.

[NBs]

Hi, I have the same problem, the lathe does not disconnect the start battery, even though it should. I have solved it by putting a breaker + on the cable from the starter battery to the dc-dc charger and I use it manually. Maybe it could be solved by programming the charger? I have a blue thoot transmitter on the charger and an app on the phone, but I don't really understand these...

[s/v Jedi]

Originally Posted by SVLupine

I have a Renogy DCC1212-20 converter installed to charge my 800Ah Lithium bank from the alternators that charge my 2 starter batteries which are FPV M24-700st 560cca,700mca 105rc. I have two engines with Traditional 35amp alternators with a BlueSea 5511E switch between the starters/alternators and batteries. I usually run one engine at a time so I have a switch to power on the DC/DC converter when underway. The converter is draining both my starter batteries somehow and I’m not sure why.
I’ve included a wiring diagram that shows how I have it set up. The switch has a combine feature that can isolate each battery/starter or combine to form one bank from the two. I’ve been running the switch on combine so the alternator that is running would charge both start batteries and then the house when they are full. It appeared to be working based on the app that shows current going into the house bank, but keeps draining the start batteries. It should stop charging if the batteries drop below 12.7v. The other thing I noticed is that the 30amp input fuse turned brown but didn’t blow.
1. Can anyone tell from my wiring diagram if the wiring is set up weird? Did I create a problem using the bluesea switch how I did ?
2. I did run both engines and didn’t think to turn the DC/DC off – Could running both 35amp alternators have damaged the unit?
3. The manual calls for ANL fuses but I wasn’t able to get one when I installed it and was advised that a standard auto ATO or maxi fuse would be fine. Not sure if the fuse choice is contributing to the problem or not.
4. I’ve reached out to Renogy about the issue but haven’t gotten a response yet.

You have included some info from Renogy on the voltages that make it start or stop charging. Have you programmed it for a smart alternator? It should be set for a standard alternator.

I use Victron equipment and they do great with alternator detection; it seems Renogy claims to do this right so look for a wrong setting.

On the installation… I hope you understand it doesn’t charm me a bit. You have a spaghetti of wiring instead of neat bundles. The fuse isn’t fully inserted into the holder, which has created a high contact resistance with overheating as the result. You need to replace both fuse and fuse holder.

Some pictures added for inspiration on what good installations look like

[SVLupine]

Thanks for the reply, I don't think you can program the Renogy DC/DC for a smart vs traditional alternator. The only programing is 5 DIP switches which adjust charge voltage.

*Fuse was lightly seated in holder for pic as reference, it was fully seated while the unit was running.

[secessus]

Third try to post this so will be be more concise: the old 20A with DIPs does not voltage sense so triggering is by IGN/D+ onlyu. The new one 20A version does. The charging logic screenshot in the original post appears to be from the new version.

[Tupaia]

Interesting I have 2 x start batteries connected via a Pathmaker (voltage sense relay) and a Renogy DC-DC converter on the Port side of the Pathmaker. When either of the engines are running the Pathmaker is closed allowing charge to the Li bank. The DC-DC "should" be initialised by the +ve take off from the Pathmaker when either engine is running which it does. The port side start battery the one always connected to the DC_DC has been draining mysteriously.


Never considered the drain could be due to the DC-DC. Will investigate further.

[newhaul]

Originally Posted by SVLupine

I have a Renogy DCC1212-20 converter installed to charge my 800Ah Lithium bank from the alternators that charge my 2 starter batteries which are FPV M24-700st 560cca,700mca 105rc. I have two engines with Traditional 35amp alternators with a BlueSea 5511E switch between the starters/alternators and batteries. I usually run one engine at a time so I have a switch to power on the DC/DC converter when underway. The converter is draining both my starter batteries somehow and I’m not sure why.
I’ve included a wiring diagram that shows how I have it set up. The switch has a combine feature that can isolate each battery/starter or combine to form one bank from the two. I’ve been running the switch on combine so the alternator that is running would charge both start batteries and then the house when they are full. It appeared to be working based on the app that shows current going into the house bank, but keeps draining the start batteries. It should stop charging if the batteries drop below 12.7v. The other thing I noticed is that the 30amp input fuse turned brown but didn’t blow.
1. Can anyone tell from my wiring diagram if the wiring is set up weird? Did I create a problem using the bluesea switch how I did ?
2. I did run both engines and didn’t think to turn the DC/DC off – Could running both 35amp alternators have damaged the unit?
3. The manual calls for ANL fuses but I wasn’t able to get one when I installed it and was advised that a standard auto ATO or maxi fuse would be fine. Not sure if the fuse choice is contributing to the problem or not.
4. I’ve reached out to Renogy about the issue but haven’t gotten a response yet.

Be willing to bet considering your wiring diagram you have your dc2dc sense wire constantly hot and not correctly wired to be cold when the engines are not running.

[newhaul]

Originally Posted by SVLupine

I have a Renogy DCC1212-20 converter installed to charge my 800Ah Lithium bank from the alternators that charge my 2 starter batteries which are FPV M24-700st 560cca,700mca 105rc. I have two engines with Traditional 35amp alternators with a BlueSea 5511E switch between the starters/alternators and batteries. I usually run one engine at a time so I have a switch to power on the DC/DC converter when underway. The converter is draining both my starter batteries somehow and I’m not sure why.
I’ve included a wiring diagram that shows how I have it set up. The switch has a combine feature that can isolate each battery/starter or combine to form one bank from the two. I’ve been running the switch on combine so the alternator that is running would charge both start batteries and then the house when they are full. It appeared to be working based on the app that shows current going into the house bank, but keeps draining the start batteries. It should stop charging if the batteries drop below 12.7v. The other thing I noticed is that the 30amp input fuse turned brown but didn’t blow.
1. Can anyone tell from my wiring diagram if the wiring is set up weird? Did I create a problem using the bluesea switch how I did ?
2. I did run both engines and didn’t think to turn the DC/DC off – Could running both 35amp alternators have damaged the unit?
3. The manual calls for ANL fuses but I wasn’t able to get one when I installed it and was advised that a standard auto ATO or maxi fuse would be fine. Not sure if the fuse choice is contributing to the problem or not.
4. I’ve reached out to Renogy about the issue but haven’t gotten a response yet.

Just went back and looked at all of the pictures mainly the wiring with the switch .
A couple things first what connector do you have that fuse in ? It is not a proper fuse holder.
2) looks to me like your wires feeding your dc2dc is undersized.

[newhaul]

Originally Posted by s/v Jedi

You have included some info from Renogy on the voltages that make it start or stop charging. Have you programmed it for a smart alternator? It should be set for a standard alternator.

I use Victron equipment and they do great with alternator detection; it seems Renogy claims to do this right so look for a wrong setting.

On the installation… I hope you understand it doesn’t charm me a bit. You have a spaghetti of wiring instead of neat bundles. The fuse isn’t fully inserted into the holder, which has created a high contact resistance with overheating as the result. You need to replace both fuse and fuse holder.

Some pictures added for inspiration on what good installations look like

Wire zip ties by the gross
Good looking install.

[Putt-Putt]

Wire ties?..................... Hardly. Not a wire tie in sight.

What you see in Jedi's pictures is the long forgotten art of Cable Lacing, tied with a Marline Hitch, likely using lacing tape.

And there I thought you were old like me.

[newhaul]

Originally Posted by Putt-Putt

Wire ties?..................... Hardly. Not a wire tie in sight.

What you see in Jedi's pictures is the long forgotten art of Cable Lacing, tied with a Marline Hitch, likely using lacing tape.

And there I thought you were old like me.

Now that I'm awake yes I see the proper old school lacing .
Just so rare now days to see a proper old school installation

[CatLove]

As drawn in your sketch, the switch you intended to power on/off the DC/DC is doing only half its intended function. It connects the D+IGN to +12V to power up but for powering OFF it disconnects the D+IGN and leaves it FLOATING instead of connecting it to GND like a proper ignition switch .
So :
1 - either modify the wiring appropriately to connect D+IGN to GND in the OFF position,
or
2 - could possibly just add a pull down resistor between the D+IGN and GND .



The resistor may or may not work depending on the DC/DC internal circuitry and resistor value so safest option is #1 , unless you know some basic electronics and experiment with #2

[CatLove]

Originally Posted by Putt-Putt

Wire ties?..................... Hardly. Not a wire tie in sight.

What you see in Jedi's pictures is the long forgotten art of Cable Lacing, tied with a Marline Hitch, likely using lacing tape.

And there I thought you were old like me.

Even though I AM old, I am not an admirer of old skool cable lacing.
It still has a place in aerospace, high vibration environments, etc. but there are multiple reasons this became obsolete in the boating industry.


It is too labor intensive both to assemble and to repair/modify/troubleshoot.


Cables tightly laced together have poor heat dissipation , leading to overheating of power conductors or having to oversize them.


Signal conductors tightly packed running parallel to each other exhibit crosstalk, which may degrade signals .


If you must tie cables together , use cable ties, much easier to modify/undo later.
And use a good flush diagonal cutter that doesn't leave razor sharp tie ends . You'll be happy you did when you're crawling into some narrow space and your skin encounters those cable ties.


For general purpose wiring , there are more practical solutions that in my view are better looking and much easier to work with.

[CaptainRivet]

Originally Posted by CatLove

Even though I AM old, I am not an admirer of old skool cable lacing.
It still has a place in aerospace, high vibration environments, etc. but there are multiple reasons this became obsolete in the boating industry.


It is too labor intensive both to assemble and to repair/modify/troubleshoot.


Cables tightly laced together have poor heat dissipation , leading to overheating of power conductors or having to oversize them.


Signal conductors tightly packed running parallel to each other exhibit crosstalk, which may degrade signals .


If you must tie cables together , use cable ties, much easier to modify/undo later.
And use a good flush diagonal cutter that doesn't leave razor sharp tie ends . You'll be happy you did when you're crawling into some narrow space and your skin encounters those cable ties.


For general purpose wiring , there are more practical solutions that in my view are better looking and much easier to work with.

How old is your installation?
It will look good know but that plastic ducting is for house install, not boats and will over time bridle an cracking.
Jedi's install pics are top notch and as Putt-putt commented right an old but simple art that holds up in marine install for decades. It takes a bit more time but is far superior to what you have.

[CaptainRivet]

Originally Posted by SVLupine

Thanks for the reply, I don't think you can program the Renogy DC/DC for a smart vs traditional alternator. The only programing is 5 DIP switches which adjust charge voltage.

*Fuse was lightly seated in holder for pic as reference, it was fully seated while the unit was running.

You are not experienced so make yourself the life easy and get yourself the easy as alternator relay.
In the install notes of the relay will show you how to connect it. You have all cables needed for that relay at the DC2DC location.
Saves you complex routing of an ignition wire from.the engine panel to the DC2DC locations for both engines.

The easy as relay discovers the ripple only an alternator produces and switches then on the DC2DC and when alternator of switches DC2DC off. So this cannot be fouled by other charge source as thats the case with all DC2DC as they work via voltage sensing. Eg all the victron put your shorecharger on and you see how the DC2DC starts charging the house as it gets fooled by the shorecharger thinking the alternator is running.
https://www.caravansplus.com.au/easy...c7xeJKLh7tUqjk
This is far more then a classical voltage sensing relay!
As jedi said yes replace both fuses and fuse holders, that's really bad.