How many watts can I power from the 12v cigarette lighter socket in my car please?

[expeditionist]

Hi guys

Appreciate a bit of help please. I know this isn't really an auto electrics forum, but I'm hoping maybe somebody will know anyway, not sure there's a better forum to ask this in?

So I'm disabled, and I need to find a safeguard way to re-charge my mobility scooter in my Ford Transit Connect van while I'm driving around on holiday.

My 230v mobility scooter charger is 300 watts and the easiest/cheapest way would be to plug a 12v DC to 230v AC power inverter in to my van's cigarette lighter socket while the engine is running and plug the 300 watt mobility charger in to that.

I know it's possible to buy 300w 12v power inverters, but I'm worried about being at risk of blowing the fuse for the cigarette lighter socket?

And if my van's battery is only about 55Ah is there any danger that the 300 watt mobility scooter charger will drain the van battery faster than the van's alternator is recharging it?

And do I have to buy a pure sine wave power inverter rather than one of the cheaper inverters? And is a 300 watt rating enough, or should I get an inverter with a 450 watts, 500 watts or 600 watts rating?

Your help is much appreciated, have spent ages reading up on this and not sure what to believe. Am on a budget!

Many thanks, expeditionist

 

[trev]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

Whats the fuse rating?

 

[telectrix]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

you have to realise that 300watts , although only around 1.3A at 230v, is 25A at 12v. this is way too much for your ciggy lighter which will be fused at maybe 10A. also, at that sort of current drain your 55AH battery would run flat in under 2 hours. even with engine running, i doubt the alternator could keep up.

 

[steve-the-hat]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

Most car cigarette lighter sockets are fused at 10 A, so allowing for losses, you would only be able to use a 100 W inverter in them.

You would need an inverter rated at 400 to 500 W to run the 300 W charger, by the time you have allowed for losses and start up current. This would draw between 35 and 45 A and would need to be wired in rather than plugged in.

The current drawn by the inverter would run your van's battery down in less than an hour. The van's alternator could well be overloaded if you tried to use the inverter when there was a large electrical load (such as headlights) already in use.

Most chargers will work with modified sine wave inverters, but some switch-mode ones do not. A pure sine wave inverter would work any power supply, but is considerably more expensive.

Perhaps the best solution is to have a word with the manufacturer, or supplier of your scooter and see if they do a charging kit designed for use in vehicles.

Alternatively, if your scooter has 12 V batteries it may be possible to charge them directly with an appropriate splitter relay. Such charging circuits are used extensively by caravans and motorhomes, and would be a lot cheaper than an inverter.

 

[needasparks]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

The lighter socket on my MK7 tranny is a 20amp fuse but i'm not sure if the circuit runs anything else. The calculation says i should not be able to run a 300 watt on mine but it does, for my drill batteries when i dont have power on-site and they work fine. the start up may trip the overload on it though. A trickle charger may be better but i take it for a chair it will have a special one designed for it.
There is a transit forum with guys who may give you some pointers as a lot of transits have the auxilary battery and not all the same.
good luck

 

[WDMDL]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

TBH if you're going to use this inverter a lot for charging your scooter battery, you'd be better off getting a hard-wired type inverter rather than a cigarette-lighter plug-in. The plug in type won't be so reliable over time as the connection makes and breaks and is generally poor to start with.
The hard wired type also have ignition sensing (3rd, small wire), so can be configured to only draw power when the engine is running to prevent flat vehicle batteries.
Also, you know you'll be starting off with the correct cable size and fusing if it's installed properly.

Simon.

 

[Deleted member 26818]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

To be honest, what you are proposing, is to convert 12V d.c. to 230V a.c. back to 12V d.c. all a bit pointless.
You would do better getting someone to attach a connector to the scooter battery, that you could then attach a lead to plug into your cigar lighter.

 

[telectrix]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

always assuming that the scooter is 12v. could be 24v. if it is, however 12v, i would imagine that there are suitable chargers available for 12v input. might be wise to contact the scooter manufacturer to see if such a device is available as an accessory.

 

[expeditionist]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

Thanks for all your quick replies guys, not such good news for me, but I’m grateful to have so many people start to make sense of it for me.

I’ve been out to the van to check my facts and I’ve been investigating a lot more with all your comments in mind.

My mobility scooter has two 12V 73Ah batteries in series (24V) but they’re enclosed inside the machine and it’d be virtually impossible for me, who is disabled, to get at the batteries and charge them directly. The mobility scooter has an easy to use socket on the control panel to plug the mobility scooter charger into – it’s called a Cliff socket and it looks to me just like the red 4PC/S/HVPC socket on this page (except it’s black): CLIFF Electronic Components - CliffCon Touchproof Plug and Socket Connectors . Also, my understanding is that I must keep the same charge in each battery to prevent the batteries being damaged by over-charging on the mains when charged in tandem or uneven discharge in use when discharged together, so charging the mobility scooter batteries directly / independently is probably a bad idea for that reason too, even if I could get at them.

If the amp rating of my current charger is too high, I think I'll need to look for another 230V/24V charger with less power that I can fit one of those 4PC/P/HV Cliffcon connector plugs to – the mobility scooter manufacturer hasn’t half made it difficult to use another charger!


However, I’ve double checked the mobility scooter charger (Exendis Impulse S) and it’s got a big sticker on it that says ‘24V/8A’ and both the specification sticker on the back and the manual say ‘PRIM.: 230V / 270W MAX’ (apologies, not 300W after all) and under that it says ‘SEC.: 12/24V / 8A MAX’.


I don’t understand that, could somebody please help me make sense of that specification. How can it be 8A max at both 12V and 24V? If I use a 230V power inverter plugged in to my car’s 12V cigarette lighter socket, would the amps it’d draw not be 270 watts / 12V = 22.5 amps? Or is the 8A MAX sticker referring to the output charging rate? The manual says it takes about 8 hours to charge 85Ah to 80% so maybe that’s what the 8A max marking is. I don’t understand it really.


Secondly, the Ford Transit Connect manual says that the 12v cigarette lighter socket on my van can be used to power appliances up to 10A, it also shows a 20A auxiliary power socket next to the cigarette lighter socket, but that optional socket hasn’t been fitted to my van unfortunately. So could I just change the fuse for my cigarette lighter socket to a big enough fuse maybe?


The battery in my van is actually 60Ah, not 55Ah, and the alternator is rated at 130Amps. Seems high. Maybe the alternator could keep up with the battery drain after all?

And assuming it might and the van’s electrics need to be bypassed, is it possible to create a 230V socket from the van’s battery by just cutting the cigarette lighter plug off the inverter and extending one of the wires to the positive terminal on the battery and the other wire to the negative terminal or is that not the way to do it?



Really appreciate continued help from everybody. I've got to find a way to charge my mobility scooter in my van else a holiday in winter is likely to not happen or leave me stranded somewhere on my mobility scooter with a flat battery! Thanks.

 

[Deleted member 26818]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

If the Scooter is 24V, you could install a device, to break the link between the two batteries, leaving two separate 12V batteries.
Another option, would be to replace the alternator with a 24V item, split the out put in two, one to feed a point to connect the scooter and the other to a hevy duty voltage regulatior, to reduce the voltage feeding the vehicle to 12V

 

[expeditionist]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

sorry, didn't refresh browser so my reply in 9 was typed before I read replies 6, 7 and 8, scooter is 24V not 12V, I'll do some research in to hard wired inverters, sounds better than what I asked about in 9.

 

[steve-the-hat]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

A 12 VDC to 24 VDC converter such as the Victron Orion can be used to charge 24 V batteries from a 12 V supply. Suitable model numbers are: 12/24-10 and 12/27,6-12.

Both of these converters could be plugged into a cigarette lighter socket with the appropriate lead.

Assuming you can get a suitable plug and lead made up for your scooter, this may be the most straightforward way to do it.

 

[needasparks]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

If you say it needs an 8hr charge each day, are you driving for this length each day ? if not, your wasting your time doing this. perhaps it can be charged each night where your staying or is this too obvious a problem that your camping. lol

 

[expeditionist]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

Ref . post 13, no, it should be possible to keep the scooter re-charged just by driving an hour or two a day at most because I'll not do several hours flat out on it every time I use it, planning to sleep in the back of the van on a narrow mattress, the back of the van is self enclosed and doesn't look like a vehice somebody could be kipping in, can park up and kip in the back and nobody knows anybody's in it if I get in the back discreetly, hopefully I'll get the odd campsite with power if I can find one, but they're mostly closed in winter in this part of the world and I like remote places as I'm a photographer and it's cheaper to wild camp, plus the mobility scooter is a big all-terrain mobility scooter and won't even get in the door of most hotels or guest houses, etc.

Ref. post 12, can I run the mobility scooter's charger off a 12V to 24V converter? It may charge a 24V scooter, but the charger has a 13A plug on it and needs to be run off 230V I think? And even if I could run the mobility scooter charger off a 24V supply, would the fuse / socket / van's battery be able to cope with the required power any better?

There have been some great suggestions as to how I might charge my mobility scooter's batteries but the batteries are in series for a reason and I don' think they should be charged separately even if I could access the battery's charging terminals, which I can't, the manufacturer's charger does a great job ensuring both batteries don't loose power, are always charged evenly, and never overcharged, I'm supposed to leave it on all the time at home, I don't really want to mess with the way the mobility scooter's batteries are charged unless I have to. As stated previously, the scooter is charged via a weird Cliff socket, so it isn't easy to use a different charging method or charge the batteries seperately.

Of all the solutions suggested so far, I think the best solution is to use a power inverter hard wired to the car's battery. Plus, I could use the resultant power socket for my laptop and phone and camera battery. But do I need to hard wire the inverter or can I just uprate the fuse?

Appreciate further help with my questions in post 9 if you can then?

Can anybody tell me how many amps my current battery charger uses based on the spec / questions in post 9 - is it 8 or 22.5 or another figure? And how does the 130Amp alternator in my van cope with charging the 60Ah battery and what's involved in hard wiring a power inverter to the battery?

Thanks again for all your help.

 

[Deleted member 26818]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

The alternator, has to be able to produce enough power to charge your battery, and also at the same time run the lights, heated rear windows, radio, heated mirrors, indicators, etc.
Oh and also run the engine. This is why it's output is so much greater than your battery.

I would not recommend just uprating the 10A fuse to 20A, as the wiring is most likely sized for 10A. Doing so and then drawing anything over 15A for any length of time will most likely melt the wiring.
Connecting the inverter to the battery is fairly straight forward, but will most likely involve some scrabling around under the dash. Depending of course where your battery is sited.
I believe that some have the battery under the drivers seat, whilst others have it in the engine compartment.
Your best bet would be to site the inverter as close to the battery as possible, to reduce the length of cable, and for ease of installation.

 

[expeditionist]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

OK, thanks guys, you've been very helpful.

I've been told that my local scrapyard removes batteries from cars before they're scrapped and they sell the ones that they test as good for a tenner and it'd be easy to buy a much bigger battery, so I'm looking at upgrading the van's battery maybe as well, or perhaps fitting a second battery in the van somehow, but either way, I need to source a decent pure sine inverter over 500W/600W now, off eBay I guess, and then get it hard wired by persuading a mate to help me.

Leave it with me then, thanks again for all your advice, regards, expeditionist

 

[benji]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

mines got a plastic cover on it and its states 55w max

 

[Deleted member 26818]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

I wouldn't be too bothered about obtaining a larger Amp hour battery, unless you intend using the inverter without the engine running.
I have even on the odd occasion found that having a too powerful battery, causes problems with starting. The starter moter spins too quickly for it to engage with the fly wheel.
What I would suggest, is that you search for a camper van forum, and ask their advice.
I'm fairly certain that there are set ups which will allow the charging system to charge two batteries, the second battery being charged only when the main is full.
These set us can also be arranged so that the main battery will not be discharged when using ancillary equipment, so there is always enough to start the engine.
You may even obtain advice on places that will make adaptions to your vehicle at a reasonable cost.

 

[steve-the-hat]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

I'm fairly certain that there are set ups which will allow the charging system to charge two batteries, the second battery being charged only when the main is full.
These set us can also be arranged so that the main battery will not be discharged when using ancillary equipment, so there is always enough to start the engine.
You may even obtain advice on places that will make adaptions to your vehicle at a reasonable cost.

This is good advice.

There are essentially two ways of charging a second battery: an automatic split charge relay or a diode splitter. Caravans, motorhomes, horseboxes and canal boats use these, so a quick search should find you a local firm to install one for you.

If you do fit a second battery then secure it in a proper battery box. There is a lot of stored energy, weight and acid in a battery - you don't want it to move when you brake hard!

 

[expeditionist]

Re: How many watts can I power from the 12v cigarette lighter socket in my car please

Bump...

Hi guys

Sorry to revive this post after so long but I'd appreciate some further advice please as I have a new problem with my install.

I had an auto electrician hard wire a 600w soft start inverter to my van's battery and I bought a new battery because the old one was failing and I've been using that inverter to run my mobility scooter's charger every time I start the van for over a year with no problems.

Today I've had the power cutting out on the inverter and the inverter's alarm going off for about 10 seconds every 2 minutes or so. The inverter's manual says that's either due to low input voltage or overload but I'm completely confused. I have however tested some other stuff powered off the inverter. It'll run something rated at 120 watts without problem, but the problem occurs with 3 different products between 270 watts and 522 watts so it's not what I'm running that's faulty.

I'd like to know whether or not to buy a new inverter or moan at the guys who sold me the new battery?

Any ideas please? Thanks.