Renogy DCC50S low amp charge rate?

[noraasenrab]

Does anyone have a Renogy DCC50S and have this issue? Recent install but never had more than 10amps going in from alternator. I have separated the solar to see if the amps in improve and it’s still the same.
Non smart alternator
4AWG (20mm) cable
2x100ah AGM

Current SOC is around 50% now
Thanks

 

[kbeefy]

How far and what connections between the alternator and the house battery?

I assume the 2x AGM's will accept more than 10A.

 

[Browneye]

The indicator says both house and starting batteries are fully charged at 14.4 and 14.2 volts.
How are you calculating a "around 50%" state of charge?

 

[kbeefy]

I think thats charging voltage.

 

[mikefitz]

Put a high DC load on the house batteries and evaluate how the DCC 50 responds.

 

[noraasenrab]

Put a high DC load on the house batteries and evaluate how the DCC 50 responds.

I dropped the leisure batteries down to 12.2 as checked via multimeter. (1st pic) Started back up and still the same/similar charge rate. (2nd pic)
As advised on some YouTube videos I also connected the ignition sensor to see if that would make any difference, to no avail.

 

[noraasenrab]

Put a high DC load on the house batteries and evaluate how the DCC 50 responds.

I dropped the leisure batteries down to 12.2 as checked via multimeter. (1st pic) Started back up and still the same/similar charge rate. (2nd pic)
As advised on some YouTube videos I also connected the ignition sensor to see if that would make any difference, to no avail.

 

[noraasenrab]

The indicator says both house and starting batteries are fully charged at 14.4 and 14.2 volts.
How are you calculating a "around 50%" state of charge?

The apps tells you what percentage of battery is left when not being charged. I read the battery directly via multimeter and that was showing around 12.2v as explained below

 

[fratermus]

Recent install but never had more than 10amps going in from alternator.

IIRC there is a current limit feature on device, accessible from the app. Any chance it has been set to 10A?

 

[noraasenrab]

IIRC there is a current limit feature on device, accessible from the app. Any chance it has been set to 10A?

I did check these, all set correctly.
I’ve had some people say that being agm and not lithium, I wouldn’t get the full 50 anyway, however, I’m pretty sure I’ve seen people use these to good effect with all types?
As I think I mentioned it’s 2x100ah agm batteries @12v less than a few months old

 

[Browneye]

It's always the renogy crap. [shrug]

 

[TomC4306]

I don't own a DC to DC nor any Renogy products however, it seems to me that I am seeing in your screenshot 2 times as much charging as you are claiming.
Is it not the case that both the house and starting batteries are charging at 12.5 amps?

 

[fratermus]

I did check these, all set correctly.
I’ve had some people say that being agm and not lithium, I wouldn’t get the.... s I think I mentioned it’s 2x100ah agm batteries @12v less than a few months old

200Ah of retail AGM at 50% DoD can accept ~65A (0.33C), so I'd expect to see the full pull when the battery is very low.

But your screenshot shows Vbatt == 14.4v so it can't be 50%. Looks more like the bank is in Absorption accepting minimal current.

This is why @mikefitz is encouraging you to put a big load on the system while the vehicle is running to see what happens to DCC ouput. We suspect output will rise to meet demand.

I think thats charging voltage.

Unlikely, since there is no setting for starter battery voltage and that is also displayed.

 

[mikefitz]

The starter battery current value is the input current to the B2B, the house battery current is the output from the B2B

Comments.
First comment.
Unless I have missed something there is a very odd set of readings on the DCC50.
Input power to the DCC 50 is 14.2 volts x 12.59 amps = 178.8 watts
Output power to the house battery is 14.8 volts x 12.39 amps = 183.4 watts

Clearly this is impossible, even Renogy cannot produce more power out from a converter than the Input power.

Thus I question the readings provided be the DCC50. You need to confirm current readings with a DC current measuring clamp meter.

Second comment.

The voltage reading of 14.8 volts for an AGM battery indicates its at a high state of charge and thus I would not expect it to accept much current. However this voltage is at the DCC50, the connection to the house battery may be experiencing voltage drops at; connections, fuses, breakers , cable resistance, poor contact, poor quality buss bars, problems at the battery posts, vehicle chassis connections. Thus the voltage at the house battery across its terminals may much lower than the voltage seen by the DCC 50.

Suggestions.
Check the wiring carefully, especially the negative paths that may be via the vehicle metal .
Try to confirm the DCC 50 current and voltage readings.
Put a high DC load on the house batteries, greater than 50 amps, see what current the DCC 50 can deliver
If you can measure current connect the AGM direct to the starter battery with the engine charging. This will give you some idea of the current the AGM will accept at 14.2 volts. I would expect 10 to 20 amps if the batteries are over 50% state of charge.
If possible establish that the AGM batteries are healthy, hold charge and have adequate capacity.

It may be the DCC 50 is faulty, once everything else is ruled this may be the case.

Good luck with the testing.

Mike