magbrin Posted November 14, 2009 Share Posted November 14, 2009 I am looking for means of charging laptop, camera battery, powering electric light, etc. when not on site with hook-up - or not on site at all. Not needing to use it for any form of heat, kettle or the like. Thinking of 300W inverter. Does anyone have any experience of inverters (I see bigger ones have to connect to the battery directly, the one I am looking at can be connected to a 12v socket), and would this do the job? Does it use power to do the "inverting" job or just the power required to do the charging and lighting, if you understand what I mean! Thanks Margaret Link to comment Share on other sites More sharing options...
Clive Posted November 14, 2009 Share Posted November 14, 2009 Hello Margaret, Your requirements for an inverter are quite moderate and one that will plug into a cigarette lighter will be powerfull enough. But a few words of warning and a little advice. Why do you need an inverter to power an electric light? It is far better to use low voltage lighting, either 12 volt flourescent lighting with 8 watt tubes or LED lighting which is increasingly available in various configurations. Have a look at www.ledbulbs4u.co.uk for a start. Be carefull using a cheap "modified sine wave" inverter to power a phone, camera or a laptop. Some will work but others will not and frequently end up damaging the inverter. To be sure use a "Pure Sine wave" inverter to power such chargers or probably more cost effectively purchase the dedicated low voltage chargers for your phone, camera and laptop. Take care C. Link to comment Share on other sites More sharing options...
spospe Posted November 14, 2009 Share Posted November 14, 2009 Margaret To answer one of your questions, inverters are about 90% efficient, so roughly 10% of the power they draw is used to run the inverter and not to do any useful work at the load. So if you connect a 50-watt load, you will take about 55 watts from the battery. I have an 80-watt inverter and never found the need for anything more powerful. It is used for charging, beard trimmer, toothbrush, camera batteries, mosquito repellent, laptop (not all at the same time). Remember that a 300-watt inverter will draw about 30 amps from the battery at full load, so it will not last long at that rate. Michael Link to comment Share on other sites More sharing options...
magbrin Posted November 17, 2009 Author Share Posted November 17, 2009 Thank you both for your tips! Will pause to consider what action to take. Incidentally as a "new user" perhaps you could advise me if this query should really have been submitted to the "Hints & Tips" forum? Margaret Link to comment Share on other sites More sharing options...
boxer1 Posted November 17, 2009 Share Posted November 17, 2009 Clive What is a dedicated low voltage charger. I have a 300 watt inverter and use it to charge my laptop and phone. I read somewhere that modified sine wave can damage a laptop. is this true. Link to comment Share on other sites More sharing options...
Guest Tracker Posted November 17, 2009 Share Posted November 17, 2009 magbrin - 2009-11-17 9:35 AM Thank you both for your tips! Will pause to consider what action to take. Incidentally as a "new user" perhaps you could advise me if this query should really have been submitted to the "Hints & Tips" forum? Margaret Welcome to the madhouse Magbrin. My understanding is that questions asked are supposed to go in the Motorhome Matters bit and advice or tips given should be aimed at the Hints and Tips bit - but I could be wrong - I often am! Link to comment Share on other sites More sharing options...
Clive Posted November 17, 2009 Share Posted November 17, 2009 Hi Boxer (and all) If you go into a reputable computer shop with your Laptop and ask for a 12 volt charger they will sell you one. Similarly with your digital camera and the camera shop. My own experience with "modified sine wave" inverters and Laptops is that the inverter gave up first and turned into a smelly house brick. That was a cheep Maplin 300 watt jobbie. But it worked fine with my own Laptop (Toshiba) but a friends Del caused the inverters demise. Its equally possible that the Laptop power supply module could have failed first but that was not my own experience. The non compatability was instantly identified, the inverter just stopped when the power supply for the laptop was connected. No actual laptop needed. After three retries the inverter went POP. If however you have a pure sine wave inverter then everything within its power capabilities should work, not just some. Hope that helps C. Link to comment Share on other sites More sharing options...
lennyhb Posted November 17, 2009 Share Posted November 17, 2009 I always use dedicated 12v Power supplies/Chargers for laptop/printer/phones/cameras etc., I have a 150w mini inverter for emergencies. One point a lot of cheap inverters don't like running without a load, I had one that went with a big bang it was charging a phone at the time when the phone was fully charged the load on the inverter was minimal result BOOM! and dash lights, speedo & everything else on the same circuit as the socket in the car went out with the fuse. Link to comment Share on other sites More sharing options...
catinou Posted November 18, 2009 Share Posted November 18, 2009 We spoke to the salesman who sold us our new van (5 months and counting...... :-D ) about fitting a solar panel and invertor and he told us that we would have to sign a waiver if they fitted it, as it would void the manufacturer's (Burstner) guarantee, - they could not guarantee the loads on the wiring would not damage it if we used too may appliances together..... anybody know why this is please? Is it just this manufacturer? :-S Link to comment Share on other sites More sharing options...
lennyhb Posted November 18, 2009 Share Posted November 18, 2009 If they are a genuine Burnster approved dealer any work they do should be covered. Link to comment Share on other sites More sharing options...
catinou Posted November 18, 2009 Share Posted November 18, 2009 That's what we think - they are by the way - apparently they had problems with another motorhome where the guy ran every conceivable appliance at the same time and "fried" the wires. :-S Perhaps we'll wait until the Truma gas fuel cell is released next year instead (?) Link to comment Share on other sites More sharing options...
Brian Kirby Posted November 18, 2009 Share Posted November 18, 2009 I would suggest you provide full details to Burstner UK, pronto, and seek their guidance. On the face of it, there is no obvious reason why the Burstner guarantee should be voided, provided one of their authorised dealerships does the work. That is supposed to be the reason you buy from an authorised dealer. It may be that the guarantee will only remain valid if these items are factory fit, have you checked this possibility? It may be that by piercing the roof covering, just the six years water ingress warranty would be voided. However, I'm sure there used to be a clause in the warranty that said to maintain it in force, only authorised dealers could mount accessories (and they must notify Burstner that the accessory has been fitted). Whatever may be the case with that, there is no reason the whole warranty would become void. If you don't get satisfaction, cancel the order and transfer to a reliable dealer. I think amber lights are coming on for this dealer!! Link to comment Share on other sites More sharing options...
Andy_C Posted November 18, 2009 Share Posted November 18, 2009 catinou - 2009-11-18 12:51 PM That's what we think - they are by the way - apparently they had problems with another motorhome where the guy ran every conceivable appliance at the same time and "fried" the wires. :-S If it 'fried the wires' then the system is inadequately fused. This should never happen. Perhaps we'll wait until the Truma gas fuel cell is released next year instead (?) Around €6000 I believe... AndyC Link to comment Share on other sites More sharing options...
Brian Kirby Posted November 18, 2009 Share Posted November 18, 2009 catinou - 2009-11-18 12:51 PM That's what we think - they are by the way - apparently they had problems with another motorhome where the guy ran every conceivable appliance at the same time and "fried" the wires. :-S Perhaps we'll wait until the Truma gas fuel cell is released next year instead (?) That would be because the inverter should not have been connected via any of the van's 12V wiring, but should have been located as close as possible to the habitation battery, and connected directly to it via an appropriately sized fuse and cables (as stated above). In this way, whatever was done to the inverter, it should have had no impact upon Burstner's installations and could not have "fried" the van's, or its own, wiring.The inverter, depending on capacity, should either be connected to feed the van's 230V suppy (via a mains relay that isolates the inverter 12V supply when connected to a mains hook up), or be connected directly to a handily located 230V socket separate from the van's other mains sockets. This firm, basically, is seeking a waiver from you, because of their own incompetence!I tell ya, BIG AMBER LIGHT!! Link to comment Share on other sites More sharing options...
Clive Posted November 18, 2009 Share Posted November 18, 2009 That,s just about right Brian. C. Link to comment Share on other sites More sharing options...
Frankkia Posted November 18, 2009 Share Posted November 18, 2009 It should also be noted that a 300w inverter should not be plugged in to any cigar type socket! Yes the manufacturers often sell them with a lead with a cigar plug as well as as one for a direct connection to a battery but the small print will tell you to only use the cigar lead up to 150w. The socket on your dash is only rated at 15 amp MAX! therefore it will either blow a fuse or start to overheat at 180 watts (and that is just for a short period) - no pun intended. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 19, 2009 Share Posted November 19, 2009 magbrin - 2009-11-17 9:35 AM Incidentally as a "new user" perhaps you could advise me if this query should really have been submitted to the "Hints & Tips" forum? Margaret This is a link to an earlier forum thread that may useful: http://www.outandaboutlive.co.uk/forums/forums/thread-view.asp?tid=16757&posts=13 Motorhome Matters or Hints and Tips? In principle - based on the stated purpose of each of the two sub-forums - anything motorcaravan-related other than 'friendly chat' (whatever that is!) should go in the Hints and Tips section. In practice, people post indiscriminately to both sections with Motorhome Matters getting the lion's share of inquiries and attracting the largest audience. Hints and Tips was originally set up to contain (as anyone might reasonably expect from its title) handy hints and tips on motorhome subjects, but, for some bizarre reason known only to the Warners chaps, inquiries were suddenly assigned to it. Since then, Hints and Tips has confused new forum members and compelled anyone interested in responding to inquiries to look in two places rather than one. I suggest you stick solely to Motorhome Matters unless you want to add something to the "USEFULL TIPS" thread on Hints and Tips. Link to comment Share on other sites More sharing options...
Curly Posted November 19, 2009 Share Posted November 19, 2009 Hi Michael just picked up this thread and would like a little more of your calcs. on our system. I should say that I am an absolute dumbo on electrics. I have 2x110 amp hr batteries and a 1800w inverter used mostly for the wifes hair dryer which is 1250 watt when off site which is on for approx. 3-4 mins max. From your figures @ 90% iffecient it will draw 1375 watts so am I correct that for say 4 mins use it would take from the battery about 7-8 amps (1375/13=114.6amps/15) or am I way off beam. 8-) 8-) Link to comment Share on other sites More sharing options...
spospe Posted November 19, 2009 Share Posted November 19, 2009 Curly - 2009-11-19 9:15 AM Hi Michael just picked up this thread and would like a little more of your calcs. on our system. I should say that I am an absolute dumbo on electrics. I have 2x110 amp hr batteries and a 1800w inverter used mostly for the wifes hair dryer which is 1250 watt when off site which is on for approx. 3-4 mins max. From your figures @ 90% iffecient it will draw 1375 watts so am I correct that for say 4 mins use it would take from the battery about 7-8 amps (1375/13=114.6amps/15) or am I way off beam. 8-) 8-) Curly You are not way off, but there is a small error, in that you should be dividing the 114.6amps by 12 not 15 and this gives a figure of about 10 A/H for the power drain from the batteries over a 5 minute period. Note: at very high current drain, the above 'simple' arithmetic does not tell the true story. Batteries are rated at (typically) the '20-hour rate' and this means that current which would drain the battery in 20 hours. In your case, with 2 x 110 A/H batteries this would mean a current of 11 amps. If the current is less than that, then the apparent capacity will be larger (the battery will last longer), if it is higher then the battery will 'go flat' quicker. At a current of nearly 115 amps, my guess is that the effect on the battery would be something like twice the above simple calculation and that you should allow for a loss of about 20 A/H. This is something of a guess, but it should be on the safe side. Michael Link to comment Share on other sites More sharing options...
Brian Kirby Posted November 19, 2009 Share Posted November 19, 2009 And, just in case the point is missed, you'll need vary large section 12V cables for those 115A, and appropriate fuse and fuse carrier. You won't get those from Halfords! Link to comment Share on other sites More sharing options...
lennyhb Posted November 19, 2009 Share Posted November 19, 2009 Cheapest way of buying large section cables is buy a pair of jump leads, do make sure they are copper cables a lot of cheap jump leads use aluminium & yes you can get these from Halfords. Link to comment Share on other sites More sharing options...
alistair Posted November 20, 2009 Share Posted November 20, 2009 I'm a little late with this response to the original query. We use a cheap Maplins 300W inverter and it has served us well for three years when we choose not to use power on sites. We have had no problems charging laptops, cellphones and camera batteries. For the first season I ran it off the vehicle cigarette lighter socket. I tried it only once with two laptops at the same time. Even though this was only about 15 amps, it caused enough voltage drop in the wiring to the socket that the inverter low voltage alarm sounded and the inverter cut out when the battery voltage dropped only slightly after a short period of use. After that I was careful never to have more than one laptop plugged in at a time. The only problem was when the vehicle battery ran down. The inverter's low voltage alarm goes off at anything below about 11.5 volts - ample warning to stop using it to preserve what's left to start the engine. I dismantled the inverter and removed the sounder as the inverter saves itself by shutting down at just under 11.5 volts, and we preserve our hearing. I have now installed a 20 amp socket in the living area and connected it directly to the leisure battery with 6mm wires. No voltage problems now, and the starting the engine is no longer under threat. I still only charge one laptop at a time so the inverter doesn't get too hot - I've convinced myself that if I don't drive it too hard it will last longer! Link to comment Share on other sites More sharing options...
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