Jonathan M Posted December 17, 2021 Share Posted December 17, 2021 (edited) 12v 7000mAh starter battery failed at patch today - had started Irvine 46 a couple of times but fell off a cliff the third time, glow meter dropped to almost nothing when using the starter. Had been fully-charged a few days ago, used for starting and glow plug maybe a dozen times since. Back home on the multimeter it read 12.28v. I'd always previously charged on 1A but found my charger set to 6A from the last time. Have I damaged the plates?! It is a Yasua NP7-12S, about five years old with very light use over that time. Currently re-charging at 1A. If it is damaged would repeated gentle cycling recondition it to health, or time to buy a new one? Edited December 17, 2021 by Jonathan M Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted December 17, 2021 Share Posted December 17, 2021 Go on spoil yourself buy a new one,, They used to last forever, around 10 years but not any more,,, I bought a 4000 mah 4s lipo for my field box, tapped at 3s for all but my starter which runs on the 4s, it will start all my stuff summer and winter and much lighter. Quote Link to comment Share on other sites More sharing options...
Keith Berriman Posted December 17, 2021 Share Posted December 17, 2021 Is it possible to have the volt meter on while using stater and the on a motor if it drops badly yes time for a new one. Alternative is an an old Lipo Quote Link to comment Share on other sites More sharing options...
kc Posted December 17, 2021 Share Posted December 17, 2021 It would be worth checking that the charger is working properly before buying a new battery! Of course using a Lipo means using a proper Lipo charger and not just any old charger, so factor that cost in if you are not an electric flyer. I wouldn't expect a Lipo to last any longer than a lead acid gel cell, if as long..... Shop around for a new gel cell as prices vary and an online delivered price proved the best buy for me. A 12v 7 amp will also start your car in an emergency. The old useless gel cell 12v has some uses as a weight or even a rightangle block whilst building. Quote Link to comment Share on other sites More sharing options...
SIMON CRAGG Posted December 17, 2021 Share Posted December 17, 2021 Having had several of this type of battery over the years, I gave up on them many moons ago. For more or less the same price I purchased a decent leisure battery via an e.bay supplier. I NEVER charge Lipos at home. I also purchased a 100w solar panel second hand (plus control box), and do all the charging etc. up the field. Quote Link to comment Share on other sites More sharing options...
Andy Stephenson Posted December 17, 2021 Share Posted December 17, 2021 I replaced the battery in my flight box with a 4s LiFe D cell pack. LiFe cells have very low self-discharge and degrade more slowly than LiPos when left charged. The standard 7Ah sealed lead acid batteries I used for decades always failed after a few seasons, now they are just used as weights. Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted December 17, 2021 Share Posted December 17, 2021 (edited) The small 12V sealed Gel batteries will not tolerate an incorrect charging regime and cheap wallwart chargers that are often sold with these batteries will kill them stone dead in no time. If handled correctly they should last for ages. i.e correct initial charge current , usually 0.1C and correct end voltage - 13.3V is a safe end point for float charging but certainly no more than 14V for an overnight recharge. Just charging at 1A without taking account of end voltage is not good and likely to cause heating and damage to the battery and destroy its capacity. I've changed dozens of these batteries in UPSs when I was at work and was surprised at how rubbish the on-board chargers were - made a fortune for my boss though........ Probably better of with a Lipo or similar for your field box - I'll go that route when my ancient Gel battery in my flight box does eventually pack up. Edited December 17, 2021 by Cuban8 Quote Link to comment Share on other sites More sharing options...
J D 8 Posted December 17, 2021 Share Posted December 17, 2021 Boost charge limit on a Yuasa NP7-12 is 1.5a so it is likely kaput. Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted December 17, 2021 Author Share Posted December 17, 2021 Thanks folks - I realise that I've properly cooked it! Don't want to down the LiPo route, prefer the simplicity and safety of Pb, and weight isn't really an issue (the 7Ah 12v balances the 1/2 gallon tank at the other end of my field-box/stand). This one actually lasted me very well (until I recently attempted batterycide - twice at least! - by charging at 0.85C) and they're not dear, so I'll just order a new one. But one question for Cuban8: you say charge at 0.1C which my Fusion charger can do (just set it to 0.7A), but I can't change the voltage end-point on it to less than 14v. Surely this is safe enough for fairly regular overnighters as I did for years? Quote Link to comment Share on other sites More sharing options...
Keith Berriman Posted December 17, 2021 Share Posted December 17, 2021 Hi Jonathan there my be two types of battery one for light use in alarm systems and one for power tools just seen these on Amazon around £19 and suitable for drills Quote Link to comment Share on other sites More sharing options...
Nigel R Posted December 17, 2021 Share Posted December 17, 2021 Having gone lipo in the flight box I've not looked back. One on the starter. One to run the pump and backup glow starter in the panel, and as a backup for the lipo on the starter. Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted December 17, 2021 Author Share Posted December 17, 2021 54 minutes ago, Keith Berriman said: Hi Jonathan there my be two types of battery one for light use in alarm systems and one for power tools just seen these on Amazon around £19 and suitable for drills That makes sense Keith. The alarm system type would have thin plates (like a marine leisure battery, for nav and cabin lights, electronics etc), whereas the drill type would have thicker plates (car and boat engine start batteries for cold-cranking). Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted December 17, 2021 Share Posted December 17, 2021 I too gave up on Pb`s a long time ago. Max charge for a 7Ah would be about 1 - 1.5A, otherwise it will be destroyed. The charge voltage for a car is 13.8V so this must not be exceeded. If I do use Pb`s for any reason then I use my normal Lipo charger which will cut off when full. I now only use nice, light, old, puffed up Lipos which power the starter, pump and glow for a long time. Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted December 17, 2021 Author Share Posted December 17, 2021 I'm hearing all the preferences for switching to LiPos so (as I'd like to fly this weekend) I'm going to try that route - at least as an interim solution! I've got a pair of good but completely redundant 3s 3300mAh LiPos - I assume 3s would be the correct voltage rather than 4s? Quote Link to comment Share on other sites More sharing options...
Zflyer Posted December 17, 2021 Share Posted December 17, 2021 Charging your 12v gel battery. Optimate charger. Brill. Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted December 17, 2021 Share Posted December 17, 2021 43 minutes ago, Jonathan M said: I'm hearing all the preferences for switching to LiPos so (as I'd like to fly this weekend) I'm going to try that route - at least as an interim solution! I've got a pair of good but completely redundant 3s 3300mAh LiPos - I assume 3s would be the correct voltage rather than 4s? 3S is indeed a good choice Jon. I bought a pair of 3S 5000 hard case packs. One would have done but I can use 2 in series to give me 24 volts for starting my 35 cc petrol. My starter is a Sullivan Dynatron that will work fine on 12 v for up to 120 4 strokes. A 180 4 stroke would not turn over but with 24 v the challenge is keeping everything in line when starting! Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted December 17, 2021 Author Share Posted December 17, 2021 Thx Peter. My starter is a Just Engines one with a 4:1 reduction gearbox and rated for 12 – 15 Volts. JE add that "under certain conditions the use of LiPo batteries can overpower the starter and cause the switch contacts to weld on. Many use LiPos without problem..." but I assume this is where folks are using 4s LiPos? At full charge my 3s 3300mAh will deliver 12.6v, down to 12.0v at 80%, etc. In the meantime the 7000mAh has accepted a charge of over 1500mAh (20% of its capacity), which doesn't bode well given that a lead-acid is only normally flat when it is approaching down to 50% capacity. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 17, 2021 Share Posted December 17, 2021 If you go back to the old lead acid batteries (like the post office used to power the telephones) they were hugely heavy for their capacity but virtually indestructible and could indeed be recovered by a slow 'gassing' charge. Modern ones use a 'matrix' plate filled with a "paste". Once that is damaged in any way there is no recovery. Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted December 18, 2021 Author Share Posted December 18, 2021 11 hours ago, Simon Chaddock said: Modern ones use a 'matrix' plate filled with a "paste". Once that is damaged in any way there is no recovery. I understand. So even a smart-charger that has a desulfator function won't be able to resuscitate a modern gel-based lead acid that has been physically distorted by massively overcharging at 0.85C. Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted December 18, 2021 Share Posted December 18, 2021 (edited) 15 hours ago, Jonathan M said: Thanks folks - I realise that I've properly cooked it! Don't want to down the LiPo route, prefer the simplicity and safety of Pb, and weight isn't really an issue (the 7Ah 12v balances the 1/2 gallon tank at the other end of my field-box/stand). This one actually lasted me very well (until I recently attempted batterycide - twice at least! - by charging at 0.85C) and they're not dear, so I'll just order a new one. But one question for Cuban8: you say charge at 0.1C which my Fusion charger can do (just set it to 0.7A), but I can't change the voltage end-point on it to less than 14v. Surely this is safe enough for fairly regular overnighters as I did for years? Yes, 14V will be fine for cycle charging e.g overnight top ups. Use that method myself. Use one of these on my Bonneville's battery over winter - also suitable for Gel types https://www.sportsbikeshop.co.uk/motorcycle_parts/content_prod/470768?glCountry=GB&gclid=Cj0KCQiAqvaNBhDLARIsAH1Pq52fFbY_vW0WiNjcuVfL4lknNdg1aveF0RwHkiluvXGCPOhRxw3TYngaAuj_EALw_wcB Edited December 18, 2021 by Cuban8 1 Quote Link to comment Share on other sites More sharing options...
MattyB Posted December 18, 2021 Share Posted December 18, 2021 14 hours ago, Jonathan M said: I'm hearing all the preferences for switching to LiPos so (as I'd like to fly this weekend) I'm going to try that route - at least as an interim solution! I've got a pair of good but completely redundant 3s 3300mAh LiPos - I assume 3s would be the correct voltage rather than 4s? One (probably obvious) point… In this application with a pack of that size you shouldn’t need to charge the Lipo fully. Set your charger to 4V/cell and (due to the far lower IR vs a Pb pack) it will have plenty of grunt for anything you started with your old setup. The advantages of doing this are numerous… It’s quicker to charge before you go to the field, the batteries will last longer as they will never be stored at an elevated state of charge (SOC), and it’s safer too when you store below 4V/cell. 1 1 Quote Link to comment Share on other sites More sharing options...
Andy Stephenson Posted December 18, 2021 Share Posted December 18, 2021 It's true, cycling Li-Ion/Li-Po batteries at a lower charge/discharge level will make them last much longer. This is why when they are used in low Earth orbit satellites which see 4 cycles per day they can get 10 of thousands of cycles with something like a 20% charge/discharge cycle. Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted December 18, 2021 Author Share Posted December 18, 2021 (edited) 3s Lipo hotwire hack (didn't want to lose the starter's banana plugs just yet) worked a treat at the patch today! Used 10% capacity of the 3300mAh - as I was doing lots and lots of repeated but short CG and incidence trimming flights on half tank to keep nose light. Edited December 18, 2021 by Jonathan M Quote Link to comment Share on other sites More sharing options...
CARPERFECT Posted December 19, 2021 Share Posted December 19, 2021 On 17/12/2021 at 15:35, Jonathan M said: 12v 7000mAh starter battery failed at patch today - had started Irvine 46 a couple of times but fell off a cliff the third time, glow meter dropped to almost nothing when using the starter. Had been fully-charged a few days ago, used for starting and glow plug maybe a dozen times since. Back home on the multimeter it read 12.28v. I'd always previously charged on 1A but found my charger set to 6A from the last time. Have I damaged the plates?! It is a Yasua NP7-12S, about five years old with very light use over that time. Currently re-charging at 1A. If it is damaged would repeated gentle cycling recondition it to health, or time to buy a new one? 5 years old its done very well. Less than a £1 a year. Screw fix have some , just type 12v Alarm batteries Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted December 19, 2021 Share Posted December 19, 2021 Much cheaper from the component shop now. Quote Link to comment Share on other sites More sharing options...
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