CoolHands 816 Posted September 23, 2019 I need 2 lots of 4 aa batteries for my KO Propo transmitter. They all seem to be mega expensive which is really weird as batteries are so cheap now. I’ve found 4 Nimh for about 9 quid on eBay. Is that my only option? As I need total of 9.6v I don’t think I can see any lipo I can buy that will fit plus they’re even more crazily priced like 20 quid each! but anyway I can’t seem to find many for what is surely fairly common (ie 4 aa battery compartments?) Share this post Link to post Share on other sites
Tamiyabigstuff 832 Posted September 24, 2019 Do you have enough space in the battery compartments to fit a 4 x AA battery holder in each ? Then you could just use standard AA Ni-MH rechargeable type batteries which are quite cheap. Share this post Link to post Share on other sites
WillyChang 1814 Posted September 28, 2019 Good quality AA NiMH like Eneloops aren't cheap... you can find local suppliers with spotwelder who can built them into packs for you, or buy them tabbed. Tabbed be easier to solder to. Untabbed consumer cells can be soldered if you've got the skills & right equpment... you need soldering gear that's powerful enough to heat it quick, but not heat it so long it boils the innards. Bit wary of loose AAs in radiogear, they can shake loose. Share this post Link to post Share on other sites
wolfdogstinkus 1893 Posted September 28, 2019 Hobbyking do decent rechargable AA's and battery holders and all that stuff. Share this post Link to post Share on other sites
nbTMM 433 Posted September 28, 2019 From hobbyking: https://hobbyking.com/en_us/turnigy-receiver-pack-2300mah-4-8v-nimh-flat.html Generally with NiMH you get what you pay for however. In my transmitter I use Energizer 'recharge' AA NiMH, the made in Japan ones which are well known for being some of the best cells around. You will likely need to source them through an electronics distributor though as Energizer sell several different types of NiMH cells under similar names and appearances - the ones sold at mum and dad brick and mortar type stores are almost always crappy chinese made cells. There are also fakes being sold so avoid trying to source quality cells from places like eBay. A a low-power device like a transmitter isn't very demanding though, so likely cheap NiMHs will get you decent runtime and lifespan. Share this post Link to post Share on other sites
WillyChang 1814 Posted September 28, 2019 2 hours ago, nbTMM said: From hobbyking: https://hobbyking.com/en_us/turnigy-receiver-pack-2300mah-4-8v-nimh-flat.html Generally with NiMH you get what you pay for however. In my transmitter I use Energizer 'recharge' AA NiMH, the made in Japan ones which are well known for being some of the best cells around. You will likely need to source them through an electronics distributor though as Energizer sell several different types of NiMH cells under similar names and appearances - the ones sold at mum and dad brick and mortar type stores are almost always crappy chinese made cells. There are also fakes being sold so avoid trying to source quality cells from places like eBay. A a low-power device like a transmitter isn't very demanding though, so likely cheap NiMHs will get you decent runtime and lifespan. I have some HK Turnigy LSDs... they're ok but nothing super special IMHO... just yumcha on par with what our Australian Aldi stores sell everyday. Energizer's NiMH at one point were Sanyo Eneloops, as were rebranded by many other brands like Sony CycleEnergy, Fujifilm etc. before Panasonic bought them out. For topend cells at a good price these days I'm going to IKEA to buy their LADDA 2450, they're Made in Japan (don't confuse with LADDA 1000 which are Made in China). They work great & last as expected; they're a third the price of Panasonic Eneloops Pros. i run good AAs in my KO EX1 Mars... they're decently power hungry, depending on what module. Stock factory FM module sucks fair bit of juice, runs about 2-3hrs. Spektrum module goes 4-5hrs. Share this post Link to post Share on other sites
stu22 12 Posted September 28, 2019 Cheapest solution would probably be to buy the packs designed for cordless phones and wire them together. Only "issue" here is their low capacity, but it shouldn't really matter unless you make it a habit of running for several hours in a row and never throw the thing on the charger. https://www.amazon.com/BT18433-BT184342-BT284342-Replacement-Cordless/dp/B0742877KY/ref=sr_1_8?keywords=cordless+phone+battery+pack&qid=1569694489&sr=8-8 Of course you can get the higher capacity packs, but be prepared to pay extra. https://www.batteryspace.com/custom-nimh-battery-4-8v-2700mah-4xa.aspx Share this post Link to post Share on other sites
CoolHands 816 Posted September 29, 2019 Oh I did this now thanks I bought some for 8 quid each which have decent capacity 2500mah https://www.ebay.co.uk/itm/4-8v-6v-9-6v-AA-2500mAh-Vapex-Instant-Receiver-Transmitter-Handset-Battery-Pack/232067470541?ssPageName=STRK%3AMEBIDX%3AIT&var=531269031779&_trksid=p2057872.m2749.l2649 But while I have your attention I don’t understand why I can’t recharge from the recharge plug. I replaced the batteries so saw how things are connected inside. I think it is all original. Is anyone able to tell me why / what I can do? For some reason they made it so the orange positive wire from the recharge pin goes directly up to the mini plug in the back of the main board. and the 2 positives from the batteries are actually isolated from each other - red from one pack goes straight up to the mini plug on the board, the other pack’s red joins one half of that bus bar and then leaves it as a black wire if that makes sense. It goes as a ‘black’ wire to the first pack of batteries, (the red of which goes directly up to the board as I describe above). I suppose to get both sets in series? i don’t know. anyway I cannot use the charging plug in the base of the transmitter for its purpose as the positive does not seem to actually join the positive of he batteries, so charger shows no connection. The negative does. any ideas? They made it so it could run from a power supply as well, so I think that’s why the orange wire goes up to the board. I think some shenanigans goes on up there to then charge the batteries but on mine that doesn’t seem to work. I just want to plug into the bottom of the tx and charge. Share this post Link to post Share on other sites
WillyChang 1814 Posted September 30, 2019 dunno about yours but all TXes I've opened up the charge port is usually switched thru the main power switch - ie the battery is disconnected from charge port whilst power switch is on As for charging... IMHO typical charge port wiring is skinny leads meant for ~50mA current not even 1A (=20x). Early nicads were 500mAh meant to be charged 10-12hrs @50mA; modern NiMH are 2500mAh and they prefer being charged at 1-2A preferably on a peak charger individually (less room/time for overcharge error when fastcharging). NiMH get pretty warm too when charged fast. So if I want to charge my radios via chargeport I'd use my vintage 40yo(!!) Futaba charger that dutifully trickles at 50mA... usually plug it in for 3-4days and by weekend the 2500mAh AAs would be full. Or I take out the cells and charge them individually, 3hrs & they're done & cooled. Reinsert, play RC. Spektrum don't drink much juice, might only charge them maybe 1-2X a year... LSD NiMH helps heaps, the original type probably lost more energy from self discharge than the radio's current draw. Share this post Link to post Share on other sites
NobbySideways 113 Posted October 1, 2019 You won't believe this but the best AA Rechargeable batteries I have tried are the Plain white ones from IKEA. They last for ages, and after two years of use I've not noticed their capacity drop off much at all. Far better than the Duracell and Energizer batteries I paid much more for. I think the IKEA ones come in different ratings though, make sure you get the bigguns. Share this post Link to post Share on other sites
Juggular 4964 Posted October 4, 2019 I've converted most of my transmitters with LiPo. You might need to cut open the compartment one way, so the both compartments are connected and you can slide it in. There might be smaller LiPos that could fit in one compartment, just with less mAh. Share this post Link to post Share on other sites