Newbie battery charger questions

[TallPaul_S]

Ahh, I answered 'no' to

Is there any risk in doing this?

So, yes it's a good idea as it'll remove another possible device drawing current.

I agree there's multiple sources some which say the d250SE does trickle charge, some which say it doesn't...

At the very least, disconnecting the CTEK from the system will tell us if it's that or not.

 

[wallport]

Very difficult to access this fuse but got to it and opened its case.

Now what do I do? I was expecting something removable but can't see how to remove that orange bit.

 

[TallPaul_S]

Very difficult to access this fuse but got to it and opened its case.
View attachment 238129
Now what do I do? I was expecting something removable but can't see how to remove that orange bit.

That's a midi fuse. Just undo the 2x nuts, the fuse is basically sandwiched between the ring terminals and the holder.

 

[wallport]

Ah thanks.

Before I saw this I unscrewed the holder from the panel behind in the hope of there being enough loose wire behind to give a bit more access but no luck. Now of course it makes it impossible to undo those nuts as the case needs holding in place.

I'm not sure it's possible to undo them anyway as basically it's blind access behind the battery. Will have another look but am a bit stumped. What size spanner do I need?

 

[TallPaul_S]

Not sure off the top of my head, might be an 8mm?

If you've got a socket set that would work, looking at your fuse it looks like the cable terminals are on top of the fuse so you'd just need to undo one of them which would release one of the cables.

 

[wallport]

Correct 8mm (or 5/16 in the case of my spanners). Got it!

I will leave it off charge for a little bit to see any change but then recharge.

 

[wallport]

Fuse removed at about 16:00. Line afterwards looks straighter.
Now on charge but will have to be driven on Friday. Is it OK to drive with the fuse removed?

 

[wallport]

Now on charge but will have to be driven on Friday. Is it OK to drive with the fuse removed?

Got this back from ctek support
"Yes! It is OK to remove the fuse."

 

[TallPaul_S]

Fuse removed at about 16:00. Line afterwards looks straighter. View attachment 238153
Now on charge but will have to be driven on Friday. Is it OK to drive with the fuse removed?

Got this back from ctek support
"Yes! It is OK to remove the fuse."

Excellent, that line after you removed the fuse is looking how I'd expect it to look. The battery isn't anywhere even near full charged so I think the CTEK is definitely doing something which it shouldn't be. Whether that's faulty trickle charge function, or something else.

 

[roadtripper]

Sorry @wallport been off-grid for a week but concur with good advice from @TallPaul_S and agree it's time to disconnect the CTEK - there should be no risk as the CTEK should not kick in if it doesn't see a voltage on its charge output.

I've seen references to the CTEK reverse trickle charge but it seems remarkably sparsely documented. Even if that is the case the load you are seeing seems more than a "trickle" unless your leisure battery has very reduced current supplying capability.

How's the battery looking now in the BM2?

 

[wallport]

I kind of wish I'd posted a graph last night but it is what it is...

Unfortunately, I forgot to remove the victron fuse after charging so haven't ruled that out but...

On starting the vehicle on Thursday (25th) evening, I got a battery low indication on the starter battery. At this point I thought we had explained the drop off being down to an undocumented feature of the d250se drip feeding the starter battery even when not on hookup and regardless of the low charge on the leisure battery. I still think this must be right despite the graph above.

I sent ctek a long winded question trying to get precise details about this but just got back some sections of the user guide I already had and no answers. I will now ask them a very specific question.

I'm in two minds now as to whether to pull the victron fuse immediately to see if the drop stops or leave it and then recharge. Of course, the starter battery is no longer low (12.2v at the mo).

With a bit of luck though, we may all benefit from some clarification from ctek about this reverse trickle.

Can I just ask an easier question (apologies if you already answered this). Given that my starter battery is sometimes going low, what is the cheap/easy way to trickle charge it without solar? I'm guessing that while the van is on hookup, plugging a charger in inside the van and connecting to the 12v (cig lighter) is perhaps the best and most convenient option? Is there a preferred product? Which socket should this plug into - the one near the usb c sockets low on passenger side or the one in the tray above the dash near the drivers side drink holder or doesn't it matter?

 

[TallPaul_S]

Can I just ask an easier question (apologies if you already answered this). Given that my starter battery is sometimes going low, what is the cheap/easy way to trickle charge it without solar? I'm guessing that while the van is on hookup, plugging a charger in inside the van and connecting to the 12v (cig lighter) is perhaps the best and most convenient option? Is there a preferred product? Which socket should this plug into - the one near the usb c sockets low on passenger side or the one in the tray above the dash near the drivers side drink holder or doesn't it matter?

Yeah this will be the easiest way if you're already on hookup and have a 240v socket inside, so long as you have a permanently live 12v socket in the van somewhere. Which on a T6.1 isn't always guaranteed.

Just make sure the charger is only 5a as the 12v sockets get hot anything above that. And tbh you won't need more than 5a for keeping the SB topped up anyway.

 

[wallport]

so long as you have a permanently live 12v socket in the van somewhere.

Just tested and both of those sockets are live with ignition off.

 

[roadtripper]

So my frustration with the 250SE manual is it covers both the commonly used 250SE and the uncommonly used SmartPass and it's not always clear which one they are talking about.

But as I read it the 250SE should only be doing a trickle charge from it's solar input:


There is another trickle charge mentioned but it's on the next page so that's actually a list of the SmartPass functions

And if you look at the list of properties at the end then trickle charge voltages are only mentioned in the right hand SmartPass column:



So best I can tell from the manual the 250SE trickle charges from solar input only

The SmartPass 120s trickle charges the starter from the leisure

I don't think you have solar input to your 250SE?

 

[wallport]

So best I can tell from the manual the 250SE trickle charges from solar input only

From the manual, I agree. It's just that I'm lacking any other explanation for my battery seeming to have load when nothing else is connected.

I don't think you have solar input to your 250SE?

Correct.

I have asked ctek the specific question, hopefully we'll have an answer tomorrow.

 

[wallport]

Response from ctek - I think there were some issues with Swedish translation as it took a few goes but got there in the end:

There are no circumstances when D250SE can draw current from the service battery! Please check if there are any consumer connected or if possible a ampere meter for deeper trouble shooting.

Please also check the idling voltage of your battery. A 100% charged battery shall have at least 12.6v after 12 hours. If it is under that voltage a suspect battery/cell failure can be the root cause?

So my theory is dead but then again maybe so is my battery .

I don't think it passes that 12.6v test after 12 hour test in any recent examples.

 

[TallPaul_S]

I don't think it passes that 12.6v test after 12 hour test in any recent examples.

It could be failing that due to the draw on the battery which we've not been able to identify.

To test this correctly you need everything disconnected getting the battery, ie fully charge it, disconnected everything then check the voltage after 12 hours.

I still reckon it's the CTEK, there were ripples in the voltage which disappeared when you removed the fuse.

If the van isn't being used for a week or so, I'd leave the CTEK fuse out, pop it on hookup to fully charge, remove it from charge then monitor it with all the rest of the normal stuff connected, so only the CTEK disconnected.

 

[roadtripper]

Thing is CTEK support will tell you how it is supposed to behave.

It's still possible it has an intermittent fault in the output stage that is draining the battery.

I'd actually suggest charging and disconnecting everything and the CTEK, that way only the BM2 and the mains charger is connected. Then if anything drains at that point we know it's the mains charger.

Then if there is no drain add the CTEK back in and see if it reappears.

 

[wallport]

Thanks both. What I think I will do first after charging is to remove the victron fuse as well so nothing is connected (I would remove the battery terminal if I could be bothered but...). If the battery fails their test after this then I guess it's got a problem regardless of what else is going on.

I am assuming this 12.6v after 12 hours test is agreed as valid?

Incidentally, I suspect my starter battery fails this test but despite a couple of low battery warnings (after not being driven for 2-3 weeks) has never come close to not starting the van. The voltage doesn't tail off though - for example after being driven on Friday, it's at 12.1v now and has barely dropped since yesterday.

 

[TallPaul_S]

The 12.6v is basically checking that the battery, with absolutely no load or anything connected, is holding it's full charge of 12.6v or above. If it's not holding that then it's most likely buggered.

It's good to test that first as at least you know you're then dealing with only a mystery draw and not that and a knackered battery.

2-3 weeks on the starter battery with no charging is perfectly normal if you've not been unlocking the van, so the SB dropping gradually over that time is perfectly normal. There's more systems that cause a small draw on the SB, whereas on the LB there should be nothing.

If I'm unlocking and locking the doors doing stuff on the van, I'll get a week before needing to charge the SB.

6 days to go from 12.34v to 12.0v. I've stuck it on charge today.