CTEK D250SE smart alternator question

[paltibin]

I'm just about to upgrade my leisure battery to a Renogy 100ah lithium and I've noticed a few things about the original profesional install.

The van has a smart alternator but the smart alternator signal cable on the CTEK D250SE has been left unconnected instead of connecting to an ignition switched signal. I haven't noticed a problem with the lead acid leisure battery charging when driving and looking at the start charge / stop charge voltages in the CTEK data sheet it looks like the smart alternator signal would allow the leisure battery to drain the starter battery down to 11.4V which seems very low to me.

Is it a really bad idea to leave the smart alternator cable unconnected so as not to hammer the starter battery so much? I'm feeling it's a bit of a swings and roundabouts between charging the leisure battery and not abusing the starter battery. The starter battery is EFB and not AGM.

There is a 150W solar panel connected to the CTEK as well.

This is from the CTEK data sheet and details the voltages where the leisure battery starts and stops charging in each case. Although since the CTEK asks for an ignition on signal, not an alternator on signal I don't see how it can tell if the alternator is charging except by the voltage anyway. Or have I missed something as I'm not very up to speed with smart alternators?

Conventional alternator cut-in >13.1V, for 5 sec. (engine running, alternator charging)
Conventional alternator cut-out <12.8V, for 10 sec. (engine running, alternator not charging)
Smart alternator cut-in >11.8V, for 5 sec. (engine running, alternator charging)
Smart alternator cut-out <11.4V, for 10 sec. (engine running, alternator not charging)

Thanks for reading!

 

[paltibin]

Is this a really stupid question or something? Or posted in the wrong place? Or has it been dealt with before?

Just curious why no comments yet - or am I just being impatient?

 

[Sim60]

As long as you wire in the DS250 correctly, then this will work fine. - I ran mine like this for 4 years without issue.
The whole point of the smart alternator is that it will charge the Starter Battery when it's required. If the engine is running but smart alternator is not charging then there is enough charge in the SB. If the DS250 (or anything else) is drawing large amounts of current, then the smart Alternator will kick in.
You must wire the DS250 negative to the chassis , not to the battery negative or the shunt will not see the DS250 load and not kick in correctly.

To be super correct, the ignition switched signal should be a 'engine run' signal, otherwise if you leave the ignition on, but engine not running then the DS250 can drain the SB down until it reaches 11.4V , but in reality this doesn't seem to be a problem.

Simon

 

[DXX]

CTEK 250SE has a 20A limitation, fine for most AGM set ups. 100Ah of AGM gives you 50% of the stored power. 100Ah of lithium gives you 95% of the stored power.
You may find that you would want a charger with more capacity if you plan to use more battery capacity in between driving charges, obviously it depends on how long between driving and how long you are driving for.
Either way I’m pretty sure the signal cable should be connected, I can’t imagine why it would be left disconnected.

 

[paltibin]

The DTEK installation guide just asks for "Ignition signal, +15 clamp (DIN 72552)" which (so far as I can tell) is ignition switch not engine run even though engine run would seem better.
I'll try it for a while and see how it goes! If I get any problems I'll post again!

You may find that you would want a charger with more capacity if you plan to use more battery capacity in between driving charges, obviously it depends on how long between driving and how long you are driving for.

Upgrading the CTEK to a more powerful charger would necessitate heavier cable to take the extra current. I don't want to go to that level of disassembly of the van so I'm gonna have to put up with the slower charging. I'll try it for a season and see how it goes. The solar will help a lot I hope.

 

[DXX]

The DTEK installation guide just asks for "Ignition signal, +15 clamp (DIN 72552)" which (so far as I can tell) is ignition switch not engine run even though engine run would seem better.
I'll try it for a while and see how it goes! If I get any problems I'll post again!




Upgrading the CTEK to a more powerful charger would necessitate heavier cable to take the extra current. I don't want to go to that level of disassembly of the van so I'm gonna have to put up with the slower charging. I'll try it for a season and see how it goes. The solar will help a lot I hope.

If the conversion was done with flexible conduit you maybe able to attach the new thicker gauge cable to the original and pull it through without removing cabinets etc.
A bit of silicone spray reduces the friction.