Renogy DCC50S + 100Ah Smart Lithium Install

[t0mb0]

A monitor will tell you when it’s draining but won’t necessarily tell you what’s causing it. A voltage based monitor is somewhat less useful on lithium because the voltage is so flat over a wide range of SoC.

Does your battery report current flow and/or do you have a shunt in there somewhere to do that? If so, I guess it’s a case of going out there on a regular basis to look at the draw to try and puzzle out what’s causing it. If the draw is fairly constant, I guess you could turn circuits off one by one until the one responsible reveals itself. A clamp meter would be useful to work out where the current is going.

Arguably your battery protect voltage is set a little low if it managed to get down to 3% SoC I would say.

 

[Rapt0rUK]

Here you go...

See here...

Post in thread '[Guide] DC-DC Charger (for leisure battery) -- How I Done It --' https://www.t6forum.com/threads/gui...isure-battery-how-i-done-it.15066/post-347601


...

Just read, thanks as always, looks like it's well worth having for £25 and can just took away under the seat, will get it ordered...

Need to see what's going on with that leisure battery...off to investigate the diesel heater wiring!

 

[Rapt0rUK]

A monitor will tell you when it’s draining but won’t necessarily tell you what’s causing it. A voltage based monitor is somewhat less useful on lithium because the voltage is so flat over a wide range of SoC.

Does your battery report current flow and/or do you have a shunt in there somewhere to do that? If so, I guess it’s a case of going out there on a regular basis to look at the draw to try and puzzle out what’s causing it. If the draw is fairly constant, I guess you could turn circuits off one by one until the one responsible reveals itself. A clamp meter would be useful to work out where the current is going.

Arguably your battery protect voltage is set a little low if it managed to get down to 3% SoC I would say.

Yep have adjusted it to 11.9v to see if that avoids it happening again, what I don't understand is how it happens out the blue with the same setup in place for over year...

The Renogy display is essentially acting as a shunt as its plugged straight into the battery and does show AMP's out, only thing i'm seeing is the 0.1A which i assume is the display for the diesel heater but will do some further digging...

Very strange.

 

[t0mb0]

Yep have adjusted it to 11.9v to see if that avoids it happening again, what I don't understand is how it happens out the blue with the same setup in place for over year...

The Renogy display is essentially acting as a shunt as its plugged straight into the battery and does show AMP's out, only thing i'm seeing is the 0.1A which i assume is the display for the diesel heater but will do some further digging...

Very strange.

Hmmm, yeah, if it’s very intermittent then it’s obviously a lot trickier to diagnose!

 

[Dellmassive]

Remember that the smart battery monitor is a one way device... outgoing current only..


You are not aloud to charge back through it.

...

A 0.1A draw will last months on a 100ah lithum.

Are you sure it was 100% fully charged last week?

Have you checked the dc-dc is defo putting 25A/50A in?

The battery and screen will have some self discharge current....


got some pics of the battery screen?

.

As above id raise the smart protect to 12.0v . . And test.

 

[Rapt0rUK]

So just checked wiring of the heater and there's nothing direct from the battery outside the fuse box so shouldn't be any permanent draws.

Battery is charging at the moment and don't want to interrupt it more than I already have so once it's done will post some more pics but here's the current state of play.

The battery monitor shows positive amps as it's being charged. Interestingly it's only showing 11.2A in when the charger is showing 15A.

Here's the smart protect, loads are switched off and voltage is up to 13.38v.

Have switched the profile to cut out at 12v as suggested.






Heres the Victron charger status:



And here are the various displays for the battery monitor. Will be more useful to see what's going on when it's not charging obviously so will post again when it's done...at 41% so far.

 

[t0mb0]

So just checked wiring of the heater and there's nothing direct from the battery outside the fuse box so shouldn't be any permanent draws.

Battery is charging at the moment and don't want to interrupt it more than I already have so once it's done will post some more pics but here's the current state of play.

The battery monitor shows positive amps as it's being charged. Interestingly it's only showing 11.2A in when the charger is showing 15A.

Here's the smart protect, loads are switched off and voltage is up to 13.38v.

Have switched the profile to cut out at 12v as suggested.

View attachment 121165

View attachment 121158


Heres the Victron charger status:

View attachment 121159

And here are the various displays for the battery monitor. Will be more useful to see what's going on when it's not charging obviously so will post again when it's done...at 41% so far.

View attachment 121160View attachment 121161View attachment 121163View attachment 121164

That discrepancy between the reported current output of the charger and reported input of the battery could be significant - could be exactly the phantom draw you’re looking for - it’s certainly of the right kind of magnitude to drain the battery over a week or so. Try turning off circuits (or pulling cables/fuses) one by one and see if the difference shrinks at some point.

 

[Rapt0rUK]

That discrepancy between the reported current output of the charger and reported input of the battery could be significant - could be exactly the phantom draw you’re looking for - it’s certainly of the right kind of magnitude to drain the battery over a week or so. Try turning off circuits (or pulling cables/fuses) one by one and see if the difference shrinks at some point.

Good shout, thing is with the smart protect switched to loads off, there's nothing else I can really pull.... The only things connected directly to the battery is the DC-DC charger, the smart protect and the Victron battery charger....

Think I may need to get the seat out and have a proper look...

 

[t0mb0]

Good shout, thing is with the smart protect switched to loads off, there's nothing else I can really pull.... The only things connected directly to the battery is the DC-DC charger, the smart protect and the Victron battery charger....

Think I may need to get the seat out and have a proper look...

Hmm, if there are no loads meant to be connected, then maybe it is a dodgy connection/contact to ground somewhere. I think you need to get the seat off and get in there with a meter.

Maybe just check the voltages first on the circuits that are meant to be disconnected just to check they actually are.

 

[Dellmassive]

Agreed...

15A out and 11.2A in dont add up.

possible 3.8A leak somewhere. ( unless the battery monitor is out of balance.)

as you say . . let the battery charge to 100%.

then see what the monitors says regards to any out going current.

 

[Rapt0rUK]

Plot thickens...

Had to take the charger off overnight but captured the readings to compare to this morning.

There has been some slight drop off overnight but wondering if that's just because it needs to rest a while after to coming off charge to give an accurate reading...

13.4v at switch off and 91% SOC%




This morning...




I'd say that's negligible... Interestingly got the clamp meter on the charger though and it's not 15A going in...



Which pretty much tallys with what the display is saying (now back on charge).



Going to let it get to 100% and do some more testing.

What's concerning is a fired up the engine briefly after taking off charge last night to check the DC-DC was working now the battery is awake and the alternator charging didn't kick in...need to see what's going on there!

 

[Rapt0rUK]

Charger has dropped to absorption phase, it's consistently out of sync with the clamp meter by a couple of amps...

 

[t0mb0]

Plot thickens...

Had to take the charger off overnight but captured the readings to compare to this morning.

There has been some slight drop off overnight but wondering if that's just because it needs to rest a while after to coming off charge to give an accurate reading...

13.4v at switch off and 91% SOC%

View attachment 121213
View attachment 121214

This morning...

View attachment 121215
View attachment 121217

I'd say that's negligible... Interestingly got the clamp meter on the charger though and it's not 15A going in...

View attachment 121218

Which pretty much tallys with what the display is saying (now back on charge).

View attachment 121219

Going to let it get to 100% and do some more testing.

What's concerning is a fired up the engine briefly after taking off charge last night to check the DC-DC was working now the battery is awake and the alternator charging didn't kick in...need to see what's going on there!

Is that clamp meter measurement at the battery or the charger? i.e does it still appear to be leaking ~4A somewhere? If so, a bit weird it didn’t leak from the battery overnight too.

 

[Rapt0rUK]

Is that clamp meter measurement at the battery or the charger? i.e does it still appear to be leaking ~4A somewhere? If so, a bit weird it didn’t leak from the battery overnight too.

That's reading where the charger +'ve meets the battery so if I've reading it right, that's what's going into the battery from the charger. Same spot as the one above measuring 11.56A

 

[t0mb0]

That's reading where the charger +'ve meets the battery so if I've reading it right, that's what's going into the battery from the charger. Same spot as the one above measuring 11.56A

And can you measure it at the output of the charger? Is there anything between the two other than a straight piece of insulated cable? It’s important whether that current discrepancy is real or the charger reporting the wrong number.

 

[Rapt0rUK]

So once it hit 100% there was no charge from the charger to test, I do have the Victron quick connects sat in-between charger and battery.

Think I may have gotten somewhere though...

Hard to pin down what happened first but the DC-DC wasn't charging the battery. At first I figured it was because the battery was full but then I ran the fridge with the door open/lights on phone on charge etc for a while and got the battery down to 90% yet the DC-DC was still showing a green light for the leisure battery meaning it's full...



The renogy battery comes with a ethernet cable and a button to drop the battery into shelf mode. So turned it on and off and the green light then turned amber meaning it at least registered that it was no longer full... DC-DC still not charging the battery though.




Swapped the fuse at the starter battery end, still nothing. Was starting to wonder if the Renogy box was to fault so I disconnected the +'ve feed to try and give it a restart, then sure enough, started the engine and it started charging and the full 50A picked up both at the starter battery end and on the Renogy display.




Hard to know what came first, did the Renogy box fall over after the battery was flattened or was the battery flattened because the Renogy box hasn't been working for some time and I've just not noticed it ticking down...

With the loads switched off (smart protect) the battery monitor show 0A and with loads active, there's a nominal 0.1A which I'm guessing might be the feed to the heater panel or something.




So not got to the bottom of it just yet but 1 thing I've learned, the Renogy box perhaps isn't 100% fit and forget, will need to keep a close eye on it and think I might get I to the habit of switching the loads off with the Smart Protect when the vans sat on the drive just to exclude that 0.1A and see if it drains somewhere else.

The batteries down at 90% still so will get the charger back on it this morning and see if I can pick up the discrepancy between charger and display panel.

 

[Andymc]

Good news that it restarted after disconnecting the Alt+, where is your display located? You would of thought the smart connect might of alerted you to low battery?

 

[Rapt0rUK]

Good news that it restarted after disconnecting the Alt+, where is your display located? You would of thought the smart connect might of alerted you to low battery?

Display is in the back in the camper area so we know where we're at when we're back there, need to get in the habit of checking more frequently when I've not used for a while.

I've just ordered one of the Bluetooth modules to plug into the DC-DC so I can keep an eye on that from the phone more easily.

The smart protect does send an alert to the app but only when you're connected to it so not ideal...once I hooked up to it through the app (first the first time in months) it flagged right away but if you don't open the app and connect regularly (Bluetooth) only way your going to know is when it cuts out, unless you fit a buzzerz which is an option.

 

[Steele T6]

Has anyone compared the dcc50S v dcc30S ? I am trying to understand the best solution with a Renogy 100aH battery

 

[Andymc]

I would look at how you’re intending to charge the battery, the 50s charges equally 25 for charger and 25 for solar. I assume the 30s is 15/15?
if you are planning solar I would go 50s as finding a panel with <25 voc will be difficult.
My opinion only from my limited knowledge, I’m sure someone else will chip in…