Quiescent current

[MarkH]

I am wondering why the "load" output is in the Grenadier not connected at all

Typically this is left unused so as to connect a 12V fridge & maybe a small inverter so that while on the move they're not drawing power from the auxiliary battery, thus allowing the Ctek DC charger (if fitted, a must have with a fridge) to correctly charge the auxiliary to float (100%) without interference from the fridge cycling on/off and knocking it out of the absorption/float mode. The 120S can't charge to float on it's own as it cannot control/change voltage, this is determined by the smart alternator so it could be 14.4V or 13.6V output depending on what loads are running, e.g, AC, lights etc.

 

[MarkH]

My Troopy had a 200mA parasitic load (~5Ahrs per 24hrs) after I fitted an alarm system and the wet cell lead acid battery would go flat within a week. I'd say the Gren would have similar if the advanced alarm is optioned.

 

[DenisM]

My Troopy had a 200mA parasitic load (~5Ahrs per 24hrs) after I fitted an alarm system and the wet cell lead acid battery would go flat within a week. I'd say the Gren would have similar if the advanced alarm is optioned.

Spot on: That's a major reason why I specc'd the second battery option... as well as being able to engage parking mode on a dashcam without fear of needing a jump start!

 

[emax]

Interesting thread this. I think my old defender was 200 MA when new, and with all the gumpf installed was 400. Doesn't sound much but over days and weeks if you don't drive that really adds up.

200 is a lot imho.

It's less the current which drains the battery, but more the time the current lasts. One month is 30.5 * 24 hours = 732h. With 200 mA this yields a whopping 146 Ah!

Almost 300 Ah @ 400 mA = 3.6 kWh nominally ...

I have never understood why cars take such a high current for doing nothing except supplying the clock. An RTC in a PC runs for a decade on a 3V lithium battery ...

 

[MarkH]

My Jeep GC has a ton of electronic modules involving something like 1500 computer chips or some crazy number like that. ( the new Defender would have a lot more). Anyhoo, the battery in the Jeep is an 85Ah AGM (under the driver's seat) and the parasitic load must be very low as it can sit for 4-6 weeks and still start the car no problem. I'd say the Gren will be similar with less modules & chips.

 

[DCPU]

Upper left is the Generator input.

If you follow the wiring back, this is connected to a 300A fuse in the 5 way. The 5 way draws power from the 7 way, and the 7 way draws power from the main battery.

I am wondering why the "load" output is in the Grenadier not connected at all. As far as I understand the manual, one of the advantages of the 120S is that it can manage power distribution so that the loads are primarily fed by the generator and the batteries are conserved to the maximum. But in the installed configuration this feature is not used at all.

I think the vehicle wiring is all done standard for a vehicle without the optional auxiliary battery setup and then it's for the new owner to add what circuits they want, either off the Smartpass or directly from auxiliary battery (or indeed off the main battery given a spare space in each of the Littel fuse boxes).

So does anyone know how and if the CTEK is even drawing current from the second battery when the engine is off?

Not for any normal load, no, but my understanding is the CTEK will draw current from the second battery to pulse charge the main battery under conditions were the engine is not running and the main battery is under load (quiescent or otherwise). I assume that this is set by upper and lower voltage readings(?).

 

[emax]

Thank you, very good information.

So I will test the main battery and not re-wire something. But if necesseary, I can still do it.

As far as my assumption about the drift of the ammeter is concerned, however, I have to row back. It is catastrophic, simply completely unacceptable. Within 10 minutes it was (measured with a laboratory power supply) over 600% ....

A measurement with it is actually only possible within the first 10 seconds, and that only roughly. I would never have expected that.

It confirms once again that you get what you pay for.

So I will also send this clamp back, and have already ordered another from Benning. This is a German companywith good products - which is then again around 350 euros. The Benning CM 12 is in general a capable DMM and a clamp ammeter and it offers especially the recording via Bluetooth.

I am now waiting for delivery. And then I will, before I write something or suspect, first see if it's any good.

Power Current Clamp Meter CM 12 - BENNING

www.benning.de

 

[DCPU]

It's proving far more difficult / time consuming then I had imagined; not to mention the various purchases and the cost involved.

I could understand if you park it in the too difficult to do right now column and maybe look again at a later date.