Renogy DC to DC not charging

[Blitz]

Hi all
I know this has become a popular item now and I have just upgraded to the 50A version. However. After the install everything looked OK. A week later both my Renogy Lithium batteries are dead. The alternator light is constant red which I believe is correct, the Service light shows green??
Checking the app the charger showed boost mode and bugger all amps or watts being put out. The battery mode is set to lithium and the smart alternator wire connected and showing a current when I checked it.
So why no amps going into the battery and why did they fully discharge when not used and van driven everyday to work.
Ps. I'm currently charging the batteries via a charger and both excepting current so apear to be charging OK.

Need an idiots check list to go though to try and find out what's going wrong.
Thanks Grant

 

[Blitz]

Ok
Just had another look. Batteries are charging OK from my car charger so they look to be working fine.
Now the DC charger is putting out 17amps or so according to the app. The batteries are showing a minus figure in amps. Basically with the ignition on I get a 5amp loss and with the alternator running even more.
What have I done wrong for achieving the total opposite of charging
Thanks

 

[Deaky]

Connected it the wrong way round maybe? Can you post a photo

 

[Blitz]

Hi
After a sleepless night, I thought that could be the obvious answer. Glad I have all the Bluetooth app info to see what was going on. So traced the wires back through the rear seats with the aid of Mrs Blits and... Yep got them crossed over under where I couldn't see very well and wired them to the controller the wrong way round
Thankfully just Human error.

Thanks
Grant

 

[Dellmassive]

Sorted.

 

[T6Jay]

Good to know that the batteries and the DC/DC charger survived this mishap. I think it says something about the internal circuit protection.

Now you've just got to have a good look around the van for those rogue Ahs, they must be hiding somewhere

 

[Blitz]

Yep the BMS kicked in and saved the batteries. Didn't have any problems getting them going again, no BMS to kick start so not totally flat flat. So technically I saved my self £100+ by not killing a new lead acid battery

 

[Jim Rey]

I have a renogy 50ah lithium battery that is not accepting a charge.

I’ve started an independent thread here:

Renogy 50ah lithium battery not accepting a charge

I have a renogy 50ah lithium battery that is not accepting a charge. I have spent a lot of time (frustrating hours) on webchat with Renogy. They are now suggesting that I buy a Lithium charger with re-activation capability. They have one on their website but they asking £129 for it!. I spent...

www.t6forum.com

 

[Izzy’s T6]

Ok
Just had another look. Batteries are charging OK from my car charger so they look to be working fine.
Now the DC charger is putting out 17amps or so according to the app. The batteries are showing a minus figure in amps. Basically with the ignition on I get a 5amp loss and with the alternator running even more.
What have I done wrong for achieving the total opposite of charging
Thanks

Hi,
Can I ask where you got your D+ ignition from please. I’m trying to connect a Renogy 60amp b2b charger but not sure where to get this connection from. Any help would be much appreciated.
Thanks

 

[roadtripper]

Covered in quite a few threads now, there is no real D+ on a modern stop start engine.

Any ignition live circuit will be fine. There isn't one under the seats so you'll have to put a feed in from the dash fusebox.

If you are really worried then you can use the BCM charge signal that the OE relay uses which will respect things like Start Stop cycles. That's very easy if you are replacing a factory second battery as the feed is right there under the seats. If not then you have to put your own feed in, get to the BCM, add the additional connector and get something like VCDS to enable the signal. That's a lot of work for a marginal gain in functionality.

If you are hyper concerned about the possibility of the DC-DC putting a high load on startup with a low starter battery just put a switch or small fuse in the ignition live feed somewhere accessible, then you can turn the charger off if you are ever worried.

Ignition Live Under Passenger Seat - How Its Done -

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