Ctek D250sa

[andys]

As I detailed on another thread, I put one of these in my van in place of the failed split charging relay a week ago and have been very impressed with how it has kept the leisure battery at maximum charge.

However one thing I have noticed is that 3 times this week I've unlocked the van in the morning and while I've been fiddling about plugging phone in, looking for chewing gum etc, my Thinkware F750 has announced "Shutting down due to low battery" and turned itself off. After going back out to the van one night to get something about 10 mins after shutting the engine off, I noticed that the display on the leisure battery was reading 14v and I'm now wondering if the Ctek is being a bit too ruthless about pulling charge from the starter battery in order to keep the leisure battery at peak charge.

So I went out with the multimeter after work tonight and got these readings

Leisure battery - 12.8v (agreed exactly with the display on the van control unit and also the same as it says every morning I've been getting in to the van)

Starter battery 12.4v - this seems a bit low?

I've checked the dash cam and it's set to power down at 12.2v so the starter is obviously hitting that sometimes in the morning. I've had no problem starting the engine so far but should I be worried, and if so what can I do about it?

 

[andys]

Bump. Anyone any thoughts on this?

Voltages 2 days after it was last driven are;

Leisure 12.7v
Starter 12.2v and the dash cam has turned itself off

Bit bummed off that I seemed to have replaced one problem with another

 

[Pauly]

There is a small red and black cable coming out of the charger have you connected the red to an ignition live ?
After turning off van and with no solar connected the charger should fully extinguish have you checked it's shutting down properly and not drawing any power from main battery ?

 

[andys]

There is a small red and black cable coming out of the charger have you connected the red to an ignition live ?
After turning off van and with no solar connected the charger should fully extinguish have you checked it's shutting down properly and not drawing any power from main battery ?

Yes I've connected the red to an ignition live and the thin black to ground which should switch it to smart alternator and AGM mode. I have a feeling it is continuing to pull power out after the engine is switched off as the leisure battery read 14v when I went back to it after 10 mins, but had stabilised at 12.8v after half an hour. The lights on the charger are going out straight away but I haven't actually checked the voltage the it's putting out with the ignition off so I'll do that next, thanks.

The other alternative I suppose is that there is an excessive drain on the starter battery from somewhere else, and I did cable the amplifier to the battery while I had the seats out, but it's not in use yet and I haven't put the fuse in so it can't be that. I didn't make any other changes and I had no problems with starter battery before fitting the Ctek.

 

[andys]

Checked this morning and the Ctek continues outputting 14v+ for one minute after shutting down. I might change the control wires to configure to put out the lower voltage rather than the 14.7v it outputs for an AGM (even though both batteries are AGM). Shame really but I can't have it not starting in the winter

 

[snoop6060]

Doesnt the ctek provide an extra boost from the lesuire battery to assist the starter battery if needed? Pretty sure I read this in the manual. So doubt you'll end up not being able to start it.

 

[DaveyB]

Doesnt the ctek provide an extra boost from the lesuire battery to assist the starter battery if needed? Pretty sure I read this in the manual. So doubt you'll end up not being able to start it.

I think that depends upon having the full "new" ctek kit comprising the split charger and the smart pass.

 

[Pauly]

Wasn't aware of it feeding start battery in terms of cranking but if it has solar feed coupled with a smart pass it will allow charge back through to starter battery when leisure is full

 

[DaveyB]

When I was talking to the bloke from RoadPro when he was putting that system in Fish's van, he said that because of the way the Smartpass worked it could direct juice the opposite way so if starter battery flat, you could crank on leisure battery. Even better if you install the ctek battery charger at the same time, that way when hooked up to mains you can charge the starter and leisure.

 

[snoop6060]

Argh ok. The manual does also contain the smartpass info so perhaps I've misread it. Does make sense as I wasn't entirely clear on the point of the smartpass. Sounds useful, unfortunately no way it's gonna fit!

 

[travelvolts]

I think your 250SA is behaving exactly as it should. Your van battery would be expected to be around 12.4. I think the dash cam is being a little fussy and maybe with a bit of VD in it's own wiring it is being a bit premature.

 

[andys]

Thanks, some interesting comments. There's no way I want to stump up another £200 odd for the Smartpass, though it would fit in the available underseat space. The mains charger already fitted to the van also charges the starter battery too - or rather it did in its original configuration, I haven't connected the van to mains hookup since fitting the Ctek. @travelvolts The van battery voltage reported by the dash cam also matched what it read with a voltmeter across the terminals. I must admit, if 12.4v is normal I'm not as concerned, is this due to the alternator being "smart" and only giving it as much charge as it thinks it needs?

The starter battery reads 12.4v immediately after turning off and this always drops to 12.1v after about an hour. It then consistently seems to stabilise at 12.1v for as long as I've left it. I've had no problem starting the van and I don't need to use it til next week now so I'm going to leave it without starting it for a few days and monitor the voltage to see if I have losses elsewhere I need to find.

Thanks for all the helpful suggestions

 

[andys]

Actually one other thing that puzzled me though was that in 6 months the dash cam has never turned itself off due to low voltage, but since fitting the Ctek it's doing it every day!

 

[travelvolts]

The CTEK, like most other DC-DC chargers will harvest energy from your leisure battery after the engine is switched off. It may be this that is just pulling your battery short of the dash cam wants. The engine battery is deliberately kept at about 80% to allow for harvesting during regen braking. It could also be that your battery is getting weak if it has had had a hard life. It is also worth noting that having your onboard charger charging the vehicle battery is not recommended.

 

[andys]

That makes sense if it leaves some capacity spare for regenerative braking. I'll monitor it over the weekend and if it looks ok still I'll nudge down the shutdown voltage for the dash cam. It must have been the enthusiasm of the Ctek that's just pushing the voltage over the shutoff limit, though the battery shouldn't have had a hard life, the van's only 7 months old with 6000 miles, more than 3/4 of which are motorway with very few short journeys.

 

[Vinci]

May I ask what might be the long term implications of minimising braking during driving ......I try to avoid having to hurry anywhere now.

 

[Loz]

May I ask what might be the long term implications of minimising braking during driving .......

You might drive into something

 

[andys]

Well after a week of not using, the starter battery was still at 12.1v and the leisure battery at 12.5v so I'm happy that there's nothing untoward and that it's just the Ctek pulling just that little bit more out of the battery after turning the ignition off. As @travelvolts suggested, the dash cam is just being a bit alarmist and I've lowered its cutoff voltage to 12v.

 

[andys]

Just revisiting this. While trying to find a solution to the door lock situation the van has been stationary for a couple of weeks, plugged into the mains hookup, and I found last night that the vehicle battery had gone flat enough to not be able to start. I've found before that the Ctek is quite aggressive in how it pulls power to keep the leisure battery topped up, but I'm sure the old split relay used to allow trickle charging of the starter battery and the Ctek obviously doesn't. Is there any way round this other than spending another 200 odd quid on the matching Smartpass and rewiring to accomodate it? In fact reading through the manual for the Smartpass it sounds as if that would have done the job on its own without the the 250DSA.

Edit: Just re-read the posts earlier in the thread which have answered my own question. Looks like a Smartpass will have to be the next item on my shopping list then, providing I haven't taken a sledgehammer to the van cos of these sodding locks.

 

[travelvolts]

The CTEK shouldn't draw the vehicle battery down if you have connected an ignition supply properly.