CTEK smart charger off power bank / generator (no mains)

[hwem2003]

Hi all

Has anyone tried running a CTEK (mxs 5.0) off a power bank like the below?

It says CTEK needs 220–240 VAC, 50–60 Hz, 0.6 A and presumably 0.6A is at max output, trickle draw would be much less?

What do people think? How much power does a CTEK draw just on maintain mode. Trying to work out how long one of these power banks could last. I have no mains power.

Thank you

https://www.amazon.co.uk/ALLPOWERS-Portable-Genera...

https://www.amazon.co.uk/NOVOO-Portable-Generator-...

[rxe]

One of those will easily power a 5 amp CTEK. 5 amp x 12v = 60W, even at only 50% efficiency that is 120W. But....

Expecting one of these to run for a long time on trickle won’t work. The overhead of running the inverter will be so high that the device will be flat in a short amount of time. Using it to throw 5 amps into the battery for couple of hours will be fine. If you’re going to give the battery a blast every week, this is a good solution. If you’re expecting it to trickle the battery for weeks, you’ll be disappointed.

[hwem2003]

rxe said:

One of those will easily power a 5 amp CTEK. 5 amp x 12v = 60W, even at only 50% efficiency that is 120W. But....

Expecting one of these to run for a long time on trickle won’t work. The overhead of running the inverter will be so high that the device will be flat in a short amount of time. Using it to throw 5 amps into the battery for couple of hours will be fine. If you’re going to give the battery a blast every week, this is a good solution. If you’re expecting it to trickle the battery for weeks, you’ll be disappointed.

Thanks for your response. So I am clear, by "overhead" do you mean that the process of the power bank converting its output into 220/240v will be inefficient and means it won't last long?

[Blenkiboy]

I was thinking of getting a 4-500wh unit similar to that for my garage, with the intention of running some LED lamps and charging cordless tools off it. But I read a passing comment in a review that you could only charge phones, laptops, drones, etc. off it but not tools. I’m not particularly technically minded but that can’t be right can it? 40v battery charger is rated at 92w draw so maybe three full charges plus lights? Solar panel to follow. Can PH hive-mind advise before I commit? I’ve no intention of running heating or corded tools. Thanks.

[rxe]

hwem2003 said:

Thanks for your response. So I am clear, by "overhead" do you mean that the process of the power bank converting its output into 220/240v will be inefficient and means it won't last long?

Sort of. The process of conversion will have inefficiency in it, but it should be pretty good - maybe 85 - 95%. So you put 100 watts of power in, you get 90 out. However the simple act of running the inverter will take power as well - maybe 10 or 15 watts. If you remove the load, it will shut down, but what you are doing is running a tiny load which will keep it going.

So your overall efficiency changes. When you are running it at close to full power, you’re probably getting 95%. If you are running it at 1% power, your efficiency is closer to 5%.

[hwem2003]

rxe said:

hwem2003 said:

Thanks for your response. So I am clear, by "overhead" do you mean that the process of the power bank converting its output into 220/240v will be inefficient and means it won't last long?

Sort of. The process of conversion will have inefficiency in it, but it should be pretty good - maybe 85 - 95%. So you put 100 watts of power in, you get 90 out. However the simple act of running the inverter will take power as well - maybe 10 or 15 watts. If you remove the load, it will shut down, but what you are doing is running a tiny load which will keep it going.

So your overall efficiency changes. When you are running it at close to full power, you’re probably getting 95%. If you are running it at 1% power, your efficiency is closer to 5%.

Thank you. Think I've got it...

So one of these power packs is 105,000mAh

Implies E(Wh) = 105000x12v/1000 = 1260 Wh
Divided by say 15 Watts just to run inverter would imply 84hrs "life" alone just to run the inverter. Would clearly then need to take into account the CTEK actually charging..

[finlo]

Can you not take the Ctec out of the equation and just have a power bank suppliment the car's battery then have it recharge once on the move?

[Paul_M3]

OP,

What is the exact situation you're trying to address? Maybe we could provide some useful suggestions.

I assume you're leaving a car for prolonged periods in an area without power? How long for? What car is it / what size battery does it have? Can you visit the place easily?

[hwem2003]

Yes sure. I keep the car (Porsche 997 911) in an underground car park, it has no natural light but some overhead fluorescent tubes.
There will be periods (maybe for 1-3 weeks at a time) where I don't drive the car and so would like to keep the battery in as best condition as possible, even though I understand the battery may still last ok for that period.
I want a simple solution where I can put the car on charge for a bit and easily remove the setup when I drive. It's not an issue for me to charge a power pack every week or so for example as the car park is easily accessible.
I have no access no mains power.

[rxe]

hwem2003 said:

Thank you. Think I've got it...

So one of these power packs is 105,000mAh

Implies E(Wh) = 105000x12v/1000 = 1260 Wh
Divided by say 15 Watts just to run inverter would imply 84hrs "life" alone just to run the inverter. Would clearly then need to take into account the CTEK actually charging..

No. The first one you linked to is 372 W/h.

It’s got a 200W inverter in it so I’d expect it to run for between 90 and 110 minutes at full chat, depending on how good the electronics are. If it is idling, consuming (say) 10W parasitic load, then I’d expect it to run for about 35 hours. Add a CTEK and you’ve probably got 24 hours, assuming the CTEK is doing almost no work. If the CTEK is going flat out, then you’d get about 3 hours, maybe 5, depending on the efficiency of the whole set up.

Per the above - what are you actually trying to achieve?

[hwem2003]

rxe said:

hwem2003 said:

Thank you. Think I've got it...

So one of these power packs is 105,000mAh

Implies E(Wh) = 105000x12v/1000 = 1260 Wh
Divided by say 15 Watts just to run inverter would imply 84hrs "life" alone just to run the inverter. Would clearly then need to take into account the CTEK actually charging..

No. The first one you linked to is 372 W/h.

It’s got a 200W inverter in it so I’d expect it to run for between 90 and 110 minutes at full chat, depending on how good the electronics are. If it is idling, consuming (say) 10W parasitic load, then I’d expect it to run for about 35 hours. Add a CTEK and you’ve probably got 24 hours, assuming the CTEK is doing almost no work. If the CTEK is going flat out, then you’d get about 3 hours, maybe 5, depending on the efficiency of the whole set up.

Per the above - what are you actually trying to achieve?

Thanks - please see above

[RSpiston]

I've an older CTEK charger but regardless this is a typical scenario :

Car sat on drive for 2 weeks with no use due to lockdown. Connect CTEK whilst monitoring power demand; starts off drawing 70 Watts, drops to around 30 Watts within 15 mins or so. Once battery is fully charged, the monitoring mode only draws a constant 2 - 3 Watts.

Might help or might not ?!

[GreenV8S]

You could measure the current draw on your vehicle to get a better answer, but for comparison my Mondeo takes about 1.3 Ah per day to keep it topped up - this covers the residual load, and whatever the battery's self discharge rate is. At a nominal 12V that represents roughly 16Wh per day. The battery you linked to has a nominal capacity of 372 Wh, so that gives you a maximum endurance of about three weeks. You'd need to reduce that to account for the inefficiency of the inverter and CTEK, but they're probably both relatively efficient.

The advert doesn't say what battery technology it uses. Some battery types don't like being deep discharged, so you might need to reduce that further.

[Penelope Stopit]

hwem2003 said:

There will be periods (maybe for 1-3 weeks at a time) where I don't drive the car

Not a long time to leave a car stood, during lockdown there are millions in the very same situation

Don't bother, use the car as and when and all should be good

[Paul_M3]

Penelope Stopit said:

hwem2003 said:

There will be periods (maybe for 1-3 weeks at a time) where I don't drive the car

Not a long time to leave a car stood, during lockdown there are millions in the very same situation

Don't bother, use the car as and when and all should be good

I would tend to agree with this, depending on what condition your battery is in.

In your position I would get one of these first of all:
https://www.ctek.com/uk/products/car/ctx-battery-s...

That way you can get a feel for how quickly your battery is discharging. Mine was well past its best and if I was leaving the car for prolonged periods I’d need to stick it on the CTEK. I recently replaced the battery and things are significantly better.

This is a CTEK trace from the old battery:



And this is one from the new battery:



You can see that the discharge rate is significantly lower.

[hwem2003]

All very helpful, thanks all. Will definitely take a look at the CTX too

[Searider]

Never had any issues with my 996 even when left for a few weeks.
After a week the alarm and central locking powered down - I simply had to open it with the key.
When I first bought it I was paranoid about the battery going flat.
I fitted a new battery shortly after I bought it.

[Winky151]

Bit of a thread jack but I've just bought a CTEK MXS 5.0 as I've now 2 cars which need the batteries 'conditioned'. The battery is ok but with the car sitting in the garage it needs to be connected, from the booklet that comes with the charger its unclear whether I just go straight to mode 8 or if it's best/necessary to go through all the other modes first. Answers gratefully received.

[Paul_M3]

Winky151 said:

Bit of a thread jack but I've just bought a CTEK MXS 5.0 as I've now 2 cars which need the batteries 'conditioned'. The battery is ok but with the car sitting in the garage it needs to be connected, from the booklet that comes with the charger its unclear whether I just go straight to mode 8 or if it's best/necessary to go through all the other modes first. Answers gratefully received.

It's not possible to manually select stages is it?

Either way, just select the correct battery type and connect it up. The CTEK will do whatever it needs to do. It will know when the battery is full.

[caaarl]

I would like to keep my car battery in good condition during the months the car just sits. Guessing that having a CTEK connected at all time would be the best (not possible today since no outlets available where I have the car).
Would the solution suggested by TS; using a (cheap) powerbank/powerstation (like https://www.amazon.co.uk/NOVOO-Portable-22500mAh-E... to power a CTEK MXS 5.0 be worth it (or enough) in this case?

Has anyone tried this solution and can give some feedback/advice?

Or should I just go and buy the CTEK CS Free (why no quick connectors?)?
Or keep using two extension cords, across the street, once a month during winter to charge my 997..(I have a CTEK MXS 5.0 that I use this way today)?