JohnGalway Posted July 28, 2009 Report Share Posted July 28, 2009 Hi folks, Been doing some digging about these 10amp LI batteries for a while now and I've yet to get a simple answer to the direct question "How long does one last from full charge to flat running a 100w bulb?" I know I can go to the Lightforce site and do the amp/w conversion there but I keep on hearing "they last all night" etc. Yet no one will furnish me with an answer to my original question which makes the battery appear increasingly unsuitable for my purposes. They're expensive but something like 1/3rd of the weight of a SLA battery, which would be a blessing on the hills here. But, I'm not going to buy one until I know what I'm trying to find out. If anyone here can answer that question then please do ATB, John Link to comment Share on other sites More sharing options...
SteveW Posted July 28, 2009 Report Share Posted July 28, 2009 Hi John, Sorry I cant answer any of your questions, but I thought I should make you aware of a of an incident that happened to a very good friend of mine 3 weeks ago While charging his new Deben Lithium battery it caught fire, this wasn't the first it had been charged. Luckily for him and his family it was in his integeral garage, protected with all modern day fire protection and a fire door (But no smoke alarm), he had a water feed put in for an outside tap several years ago, which had melted above the fire and suppresed it slightly (Push fit plastic pipe, does have some advantages) The house was a total mess from the smoke damage and water damage from the Fire Brigade, but all made it out alive. The Fire Chief attending told him that Lithium batteries cause many call outs ??? I was personally going to buy one, but I'm now having second thoughts, I sure he had a duff one, but it scared the that which promotes growth and vigour out of me thinking what could have been. Just food for thought, before you make your purchase, the weight saving is a strong pull though. Cheers Steve Link to comment Share on other sites More sharing options...
JohnGalway Posted July 28, 2009 Author Report Share Posted July 28, 2009 Hi Steve, Thanks for that, your mate was very lucky indeed! It was brought to my attention on another site that laptop LI batteries can cause fires alright, but this is the first time I've heard of the lamping batteries doing it. I might well stick to SLA after that. ATB, John Link to comment Share on other sites More sharing options...
Guest varmartin Posted July 28, 2009 Report Share Posted July 28, 2009 Got this off the net ....Apologies if you knew this ,..... Here is a way to get a perspective on the energy density. A typical lithium-ion battery can store 150 watt-hours of electricity in 1 kilogram of battery. A NiMH (nickel-metal hydride) battery pack can store perhaps 100 watt-hours per kilogram, although 60 to 70 watt-hours might be more typical. A lead-acid battery can store only 25 watt-hours per kilogram. Using lead-acid technology, it takes 6 kilograms to store the same amount of energy that a 1 kilogram lithium-ion battery can handle. That's a huge difference. Advantages... * They hold their charge. A lithium-ion battery pack loses only about 5 percent of its charge per month, compared to a 20 percent loss per month for NiMH batteries. * They have no memory effect, which means that you do not have to completely discharge them before recharging, as with some other battery chemistries. * Lithium-ion batteries can handle hundreds of charge/discharge cycles. That is not to say that lithium-ion batteries are flawless. They have a few disadvantages as well: * They start degrading as soon as they leave the factory. They will only last two or three years from the date of manufacture whether you use them or not. * They are extremely sensitive to high temperatures. Heat causes lithium-ion battery packs to degrade much faster than they normally would. * If you completely discharge a lithium-ion battery, it is ruined. * A lithium-ion battery pack must have an on-board computer to manage the battery. This makes them even more expensive than they already are. * There is a small chance that, if a lithium-ion battery pack fails, it will burst into flame. Link to comment Share on other sites More sharing options...
stag1933 Posted July 28, 2009 Report Share Posted July 28, 2009 John G. If your bulb is 12 volts and rated at 100 watts it will consume 8.33 amps of power. With a battery of 10 AH [ampere hour capacity] it will be flat in 1.2 hours. [10 divided by 8.33] Lead acid car batteries vary in capacity from 45-90 ampere hours and by simple calculation can be seen to last much longer. With the 90 AH battery you would get 10.8 hours of light with that bulb. Lead acid batteries are primitive technology but have not been overtaken by modern science which is why we still use them in motor vehicles today. Unfortunately there are no free meals in power circles and large capacity is obtained at the inconvenience of great weight. HWH. Link to comment Share on other sites More sharing options...
JohnGalway Posted July 28, 2009 Author Report Share Posted July 28, 2009 Sounds about right Stag, as my 20amp lasts in or around twice the calculations you made for the 10amp. The statement that was tripping me up was people saying you could get a nights lamping out of the 10amp LI. I didn't know enough about the LI batteries to say if that was true or not, new technology and such. Yet when I'd try to nail people down to a specific run time, they would mostly go silent, which spoke volumes. A free lunch wasn't on my agenda, just with increasing hip trouble and tendinitis I would like to make my life a little easier ya know I'll keep going with the SLA's, got an 18 and 20amp from last year which are in pretty good shape all the time Thanks for the replies fellas Link to comment Share on other sites More sharing options...
stag1933 Posted July 28, 2009 Report Share Posted July 28, 2009 John G. Figures are correct and worked out by `Ohms Law`. When I was a boy of 15 [61 years ago]I worked at a Radio Shop as an apprentice and one of my duties was the battery charging operation. In those days most of our rural area did not have electricity and folk relied on `accumulators` to supply the 2 volts needed to heat up the valves in their radios which also required a 120 volt `high tension` battery. [The most popular being the Ever Ready `Winner 120`.] Happy days of yesteryears ! HWH. Link to comment Share on other sites More sharing options...
JohnGalway Posted July 28, 2009 Author Report Share Posted July 28, 2009 I'm kinda glad now that I was hesitant and questioning of the product rather than rushing out and buying one. Especially with any fire risk as I charge the batteries in the bedroom which also contains my shooting gear. Fire there would not be a good result! I see you mentioning your age, Today is my Dad's 75th, he's spoken before about radios back then and getting batteries charged. I like those old stories and it's great when a few of that generation get together, usually results in tears of laughter Link to comment Share on other sites More sharing options...
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