Phil 9 Posted June 25, 2014 Share Posted June 25, 2014 I am looking to buy a to charge my lipos at the field from Currently I have 3s 2200 and 4s 3600 packs I think I want a minimum of 6 charges of the 4s packs if that is feasible from one battery but I have no idea what this equates to in leisure battery size. there are a few number crunch examples of working out the theoretical number of charges from a battery on the forum. But they all go on to say due to inefficiencies you get no where near the theoretical capacity. So I am looking for a more practical answer. Quote Link to comment Share on other sites More sharing options...
Former Member Posted June 25, 2014 Share Posted June 25, 2014 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Ron Harrison Posted June 25, 2014 Share Posted June 25, 2014 Get a Leisure Battery at 115mah to power a Lipo charger. (Halfords currently £89) Thats how I do it. Ron Quote Link to comment Share on other sites More sharing options...
Phil 9 Posted June 25, 2014 Author Share Posted June 25, 2014 many thanks. I guess Im looking at 75ah minimum. but for £90 quid I could also just buy a few more lipos and have enough to last the day (I can also get a couple of charges from my car without too much risk). I will need to have a think what way to go Quote Link to comment Share on other sites More sharing options...
Andy48 Posted June 25, 2014 Share Posted June 25, 2014 Hobbyking 4S 3600, £18 in their scratch and dent section (UK). For your £90 you would get 5 batteries. OK they may not be top notch, but at that price. ... (actually these are pretty good) Also remember, more batteries, each charged less often = longer lifespan in calender terms. No-brainer really. Edited By Andy48 on 25/06/2014 17:45:10 Quote Link to comment Share on other sites More sharing options...
Shaunie Posted June 25, 2014 Share Posted June 25, 2014 Don't go to Halfrauds, try these people **LINK** Battery Megastore. They have other brands as well but I just linked to the Alphaline ones as I have used quite a few now with no problems. A 110Ah leisure battery is about 75 quid, postage is free IIRC and it will usually be at your doorstep the next day. A 4S 3600 charging at 1C will draw just over 5Ah from the battery.This is conveniently at the 20 hour rate so the battery will return its rated capacity, so theoretically that would be 20 charges. Reasonably I would think myself lucky to get 80% of that so 16 charges, how much flying do you want to do? The two things to remember are; that the charger is obviously not 100% efficient and lead acid batteries efficiency drops off markedly as current rises i.e double the current draw and you will get considerably less than half the run time. Shaunie. Quote Link to comment Share on other sites More sharing options...
Andy48 Posted June 25, 2014 Share Posted June 25, 2014 Perhaps also remember the dangers of carrying a 110ah leisure battery in the car. In an accident the battery will carry on travelling forward. An accident is bad enough but a 32kg battery travelling at 30mph+ inside the car does not bear thinking about. The restraining links in most cars are not rated for this sort of force. Not to mention acid splashes should the battery split open. But then only other people have accidents don't they? Quote Link to comment Share on other sites More sharing options...
Phil 9 Posted June 25, 2014 Author Share Posted June 25, 2014 Posted by Andy48 on 25/06/2014 20:25:17: Perhaps also remember the dangers of carrying a 110ah leisure battery in the car. In an accident the battery will carry on travelling forward. An accident is bad enough but a 32kg battery travelling at 30mph+ inside the car does not bear thinking about. The restraining links in most cars are not rated for this sort of force. Not to mention acid splashes should the battery split open. But then only other people have accidents don't they? even without accidents it is a heavy lump to cart about with you every time you want to go flying Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted June 25, 2014 Share Posted June 25, 2014 I have this at present also as my 100A marine and leisure battery is pretty well goosed. I did use the cigar lighter socket and extended lead to feed my 4010 Junsi charger over the weekend flying, and it seemed to cope fine up to around 10A input, so got some reasonable charges done on most of my 3s and 4s batteries. I confess I left the engine running, the bonus being the air conditioning kept me comfy in between flights. It is safer as Phil9 says, and saves space, and weight ( therefore helps driving fuel consumption figures ), so Im seriously considering not bothering to replace the leisure battery., which also of course needs charging often ;( Quote Link to comment Share on other sites More sharing options...
Barrie Dav 2 Posted September 19, 2014 Share Posted September 19, 2014 Would this charger be suitable for this motor cycle sealed lead battery (YTX5L-BS (Yuasa) ? Quote Link to comment Share on other sites More sharing options...
Ben B Posted September 19, 2014 Share Posted September 19, 2014 Don't forget that even a leisure battery doesn't like being deep discharged. I've got a 100Ah marine in my shed for my lights, power tools etc and I run it down to about 50% maximum. Any lower and the cycle life expectancy goes down. If you do get a leisure battery make sure you use a good charger- this is not a time for a standard car charger which will just slam amps into it until it's full. That works fine for a car battery because most of the time (IE until someone leaves the headlights on) it's charged using the alternator and regulator. With a leisure battery you're only going to be charging it with the charger so a good 5/6 stage charger is a good investment. Leisure batteries are cheap from farm supplies shops (used for electric fences) and they tend to be reasonable quality (farmers aren't going to waste money)- some "leisure" batteries are basically just rebadged car batteries.... Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted September 19, 2014 Share Posted September 19, 2014 Interesting Ben...I'm not disagreeing with you because I don't know for definite but my understanding was that Leisure batteries WOULD stand a deep discharge....that's their whole raison d'etre....to live on a boat or a caravan & provide a few amps until they are empty (nearly!) Compare with a car battery that is designed to supply many hundreds of amps whilst cranking the engine but only for a few seconds & will then be charged back up again by the vehicles alternator. I take your point about many "leisure" batteries being just rebranded car batteries though.... Quote Link to comment Share on other sites More sharing options...
Ben B Posted September 19, 2014 Share Posted September 19, 2014 I might be guilty of repeating internet untruths but that's what I've read. **LINK** "Although these can be cycled down to 20% charge, the best lifespan vs cost method is to keep the average cycle at about 50% discharge." Quote Link to comment Share on other sites More sharing options...
Barrie Dav 2 Posted September 19, 2014 Share Posted September 19, 2014 I'm considering a compact motor cycle battery, not a leisure battery. I want it for my field box (Glow plug, fuel pump, engine starter etc). Quote Link to comment Share on other sites More sharing options...
Dickw Posted September 19, 2014 Share Posted September 19, 2014 I have had good leisure batteries and bad leisure batteries, but none of them lasted more than a couple of years of regular use before losing capacity. The car batteries I have tried seem just as good. Now I am using LifeP04 cells intended for electric bikes. They are much lighter than lead acid, have a longer cycle life, and just about all the stated capacity is useable. Not cheap, but I have a 12v 30Ah battery (4s2p 15Ah cells) built into my fleld box that is now in its third year without any noticeable degradation in performance. I got mine here **LINK** where they are available in several sizes from 4.4 to 15 Ah, but there must be other sources out there. Dick Quote Link to comment Share on other sites More sharing options...
Barrie Dav 2 Posted September 19, 2014 Share Posted September 19, 2014 Thank you Dick. I'll have a look at these. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted September 19, 2014 Share Posted September 19, 2014 You may well be right Ben B.....you can get SLA batteries that are advertised a "deep discharge" often for use by Golf-ists in their carts/buggies see here. @ Barrie Dav 2 as alluded to by Dickw a lithium based battery might be worth considering....much smaller, lighter & more powerful. I recently converted my IC Starter to Lipo with a 3S 2200mAh pack & it is briliant....rarely uses more than 2-300mAh in an afternoons flying. Maybe a 3200 or 4000 mAh 3S LiPo might do a good job in your flight box.... Quote Link to comment Share on other sites More sharing options...
Barrie Dav 2 Posted September 19, 2014 Share Posted September 19, 2014 Steve I've a 12v. Sulivan type of starter - pretty hefty. I don't know what the drain rate would be with LiPos Quote Link to comment Share on other sites More sharing options...
Masher Posted September 19, 2014 Share Posted September 19, 2014 I use a 3S 2200mAAh also - this is more than adequate and lasts for ages. Most of my IC engines are in the 90 FS range. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted September 19, 2014 Share Posted September 19, 2014 Yep....thats the same starter I have.....a 2200mAh Lipo powers it no problem...in fact much better than the 7Ah SLA battery I used to use......I tested it with a wattmeter & trying to turn over a 90 2 stroke the battery voltage dropped to around 7 volts. Using the Lipo the voltage held up much better & the starter span the motor over with great gusto.....pulling around 40 odd amps if my memory serves me.... Quote Link to comment Share on other sites More sharing options...
Barrie Dav 2 Posted September 20, 2014 Share Posted September 20, 2014 Thanks for the info. Masher and Steve. I'll try that. I've some 2200mAh and 3000's lipos. How do I use the battery with the flight panel on my box - just connect the battery as per a lead based one or is there need for some sort of a controller? Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted September 20, 2014 Share Posted September 20, 2014 Just as you would connect the lead/acid battery Barrie.....a 3S Lipo will usually knock out just under 12V a lead/acid battery just over 12V so its pretty much a direct replacement.....where the Lipo scores is in better voltage stability under load.... Personally I've fitted the Lipodirect to my starter thus doing away with all the faffing around with leads. my old 12V SLA battery sits in the flight box to power the fuel pump (I have a 2V SLA for the glow plug). As & when the 12V SLA dies it will be replaced by a Lipo....lighter smaller & recharges in an hour...whats not to like..... Quote Link to comment Share on other sites More sharing options...
Masher Posted September 20, 2014 Share Posted September 20, 2014 I've done exactly the same as Steve! Having a 'cordless' starter makes things easier and safer. Leaving my old battery in the flight box provides a back up - which obviously you never need if you have it! Quote Link to comment Share on other sites More sharing options...
Barrie Dav 2 Posted September 20, 2014 Share Posted September 20, 2014 OK thanks for that gentlemen. I'll follow your examples and use the lipo connected to the electric panel for the starter, plug and pump. I wasn't sure how a lipo would perform but your solution certainly seem very practical and is backed up by experience and as I fly 'electric' as well as i.c. the question re the charger is now irrelevant. Quote Link to comment Share on other sites More sharing options...
Barrie Dav 2 Posted September 22, 2014 Share Posted September 22, 2014 Well Steve and Masher, I've gone the lipo route and I'm pleased with the result so thanks for the advice. Quote Link to comment Share on other sites More sharing options...
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