VW T6 with smart alternator – Renogy 30A DC-DC charger barely charges

[jloperp]

Hi everyone,

I have a VW T6 with a smart alternator and a dual battery setup (starter + auxiliary). I’m using a Renogy 30A DC-DC charger. The issue is that, even with the engine running, if the alternator is not actively charging, the Renogy only delivers around 1 amp (~12 W). The alternator seems to “wake up” only occasionally, so my auxiliary battery barely charges.

Is this normal behavior with the T6 smart alternator? Do I need a D+ signal, voltage sensing relay, or maybe a D+ simulator to get proper charging? Any advice from people with similar setups would be really appreciated.

Thanks

 

[Dannyb6467]

No idea about your set up but I have the Ecoflow "alternator charger"....but because its a smart alternator that only delivers power to the vehicle battery on demand. The Ecoflow charger has to draw power from the battery. You demand power to the Ecoflow or in your case the leisure battery, the power comes from the vehicle battery, the alternator sends power to the vehicle battery...

 

[DXX]

It should be charging battery to battery not alternator to battery.
Normally on B2B chargers there is a wire to the alternator circuit to detect that the engine is running in order to activate the charger.
How old is your starter battery, if it’s not in good health the alternator output will be lost in the defective starter battery.
Has it ever worked correctly?

 

[Dellmassive]

You need to turn the blower onto No2 or turn the headlight or AC on.

This will raise the starter/alternator battery voltage up a bit allowing the dc-dc charger to deliver more power.

The reason yours is charging intermittently is it's reacting to the Regen braking voltage spikes.

If the renogy has a IGN wire, you can connect that.... But you will still need to run the fans etc to get the smart alternator to give more voltage.

 

[Dellmassive]

Is it the ip67 version you have?

Thread '[Guide] Renogy IP67 50A DC-DC Charger + MPPT (for leisure battery) -- How We Done It --'

9 Feb 2024

[Guide] Renogy IP67 50A DC-DC Charger + MPPT (for leisure battery) -- How We Done It --

..

with thanks to a Forum Member for buying this for himself, but sending it to me first to test it out.

we have the new

..

RENOGY IP67 50A DC-DC Battery Charger with MPPT​

RENOGY 12V/24V IP67 50A DC-DC Battery Charger with MPPT

Introducing the RENOGY IP67 50A DC-DC Dual Input Battery Charger with MPPT, a slim, waterproof dual charging solution perfect for confined spaces. Equipped with intelligent boost and buck logic, it seamlessly accommodates...

• Dellmassive
• dc - dc charger renogy
• Replies: 70
• Forum: Electrics, Lighting, ICE, Security

• 

.

 

[TeeCeeJay]

There is an IGN wire (small red cable) in the Renogy set up. It needs piggybacking into a an IGN live fuse under the gearstick. The main +ve feed (large red cable) in to the DCDC should come from the Starter Battery, not the alternator

 

[Skipperjonce]

Are you sure your leisure battery isn't full? The renogy DCDC is smart enough to see that and reduce or stop current completely so as not to overcharge.

Also, check you have the battery type set up correctly, as the profiles differ for AGM, Lithium, etc.

 

[jloperp]

Thanks for the help.

I have an 12V IGN wire connected to the charger, and the charger "charging" red light is on since I turn the van on (whereas without the IGN wire, it wasn't even charging).
The aux battery has been in overdischarged mode for a while (and still is after 400km).



Is there a way to change the parameters of the charger? Does somebody know if a victron charger works better?
With this level of charging and the standard use of fridge, shower, etc... the aux battery is nowhere near getting charged anytime soon.

This is my renogy charger:

12V 30A DC-DC MPPT Battery Charger | Renogy EU

The Renogy 30A Dual-Input DC-to-DC MPPT Battery Charger can charge a service battery in two different ways. The multi-stage charger can utilize connected solar panels or an alternator linked to a starting battery. It's a smart way to keep fully charged and off-grid longer whether you're using...

eu.renogy.com

 

[Dellmassive]

What is your Leisure battery?.

This shows a Gell, so AGM.

It's it's mega flat.... 11v?

.

 

[TeeCeeJay]

I'm not with my van at the moment but check that the max amp settings. I think it's top right of that screen shot you posted

 

[jloperp]

My leisure battery is a 110Ah Electronicx Gel.

I've only seen a few times where the ~30A where delivered to the battery as I was expecting...

Certainly, the I can modify the max amp settings, but that's all...

 

[TeeCeeJay]

Sorry @jloperp we are fast approaching the limit of my ability to remote diagnose an electric fault. Lucky for you the expert Mr @Dellmassive is onboard this thread and will doubtless get you going. (Although I'm going to go with, LB needs a decent external charge to get it going?)

 

[doncarlyon]

Check that your ignition live feed is actually connected up.

 

[doncarlyon]

I didn't connect mine initially and it seemed to be ok. Then after a few days i noticed it wasn't charging even with lights / heater on.

Connected it up and it's fine now, don't need to switch anything else on to trigger it. It just works.

 

[jloperp]

Thanks everyone for your support.
To add some more data to the case:

1. Ignition off / Engine off


2. Ignition on / Engine off


3. Engine on

 

[doncarlyon]

Looks like it just needs a really good charge. It's charging there now but at a fairly low rate, try switching on headlights and blowers onto number 2 to put some load on.