CARPERFECT Posted December 19, 2021 Share Posted December 19, 2021 45 minutes ago, Martin McIntosh said: Much cheaper from the component shop now. £17 plus £3.50 postage from them Quote Link to comment Share on other sites More sharing options...
John Wagg Posted December 19, 2021 Share Posted December 19, 2021 (edited) 1 hour ago, Martin McIntosh said: Much cheaper from the component shop now. £21.95 from Component shop including P&P. I got the 12v-9A version as same as the 7.5A for size and weight. https://www.ebay.com/itm/231568304738 NB charging amps less than 2.7A as noted on the side of battery. Charge mine on PB setting of Lipo charger. I did wonder whether the 5A would be suitable? Smaller and less weight. Edited December 19, 2021 by John Wagg Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted December 19, 2021 Author Share Posted December 19, 2021 Useful discussion. On reflection I'm inclined to buy a new sealed lead-acid battery as my main field-box power source, and keep the Lipo version as a backup for the starter (left on a not unsafe 50-60% charge for occasional use) rather than put all my eggs in one basket. Charging and storing the lead-acid is altogether much less fraught - just overnight after or before a day's flying then unplug and forget. But I think the standard 7Ah battery is excessive in its capacity, and could easily save weight by dropping to 5Ah or even 3.5Ah - what do other folk have? Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted December 19, 2021 Share Posted December 19, 2021 I've given up on my lead acid gel cell and just use a high capacity glow start (3800 mah capacity) and a pair of 3S 5000 20C hard case lipos. They only take about 40 mins to charge at 1C - I charge to 90% capacity. They are happy to sit around for ages till I use them. I think I've charged them twice during the year. I use a single LiPo but can double up for my large petrol. However, as I've now sold that model, I can now just make do with 1 LiPo pack and so have a spare! I know how much charge goes into them and my charger balances the cells as well as letting me know what their cell voltage difference is. These are cheapo blue Turnigy packs. I opted for hard pack to give them some protection in my flight box. The lead cell still accompanies me for the odd occasion that I need to start the OS120 in my Stampe as the with a remote glow connector, there is a noticeable dimming of the plug when using the glow start so I use the power panel glow driver and turn up the wick to get a dull red glow from my plug. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted December 20, 2021 Share Posted December 20, 2021 Bear in mind your starter might draw 30 or 40A at full load. Size and choose your battery accordingly. Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted December 20, 2021 Share Posted December 20, 2021 That's why I went for a 20C 5000 mah pack. In theory, good for 100 amps. Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted December 20, 2021 Author Share Posted December 20, 2021 On the basis that I like to have redundancy (and a 12v field power source for my Fusion charger), I've ordered an identical replacement 7Ah Pb for £21 delivered (as it happens from the same retailer I bought the original from): Yuasa NP7-12S. Will also of course keep the simple adaptor I made up for the starter's banana plugs and the 3s 3300 on half-charge in the field-box as a backup. Nonetheless today the knackered 12v still managed to start the Irvine 46 half a dozen or so times in pretty cold weather while also powering the glow-plug - although as Peter reports (and as mine has always done) did need to turn up the dial once the starter was spinning to keep the plug glowing at 1.5v. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted December 21, 2021 Share Posted December 21, 2021 Sounds like you have one of the very old style power panels? Even if you want to keep the gel cell, I'd at least run the pump/glow from a different battery, it makes a world of difference having the plug stay glowing when the starter is in use. That can be driven by a 12V of almost any type/capacity, if you really want to keep using the panel. Quote Link to comment Share on other sites More sharing options...
John Wagg Posted December 21, 2021 Share Posted December 21, 2021 Even though I bought a new battery earlier this year I have gone to a manual fuel pump and a "C" cell glow plug igniter. The only real use now for the Gel-cell is to run the starter. I still have panel connections on the box as a back up for glow plugs. There is the odd time that the "C" cell igniter won't fit because of engine access that I have separate leads to power the glow plug. This is the first year year that I have used a "C" cell and very impressed with it. (I acquired 2 second hand but never had a problem on the field with just one.) Quote Link to comment Share on other sites More sharing options...
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