BigLion 4 Posted May 7, 2022 Hi everyone! First post here so I hope it's not too Noob for you all , but little out of the ordinary so wondering if you've seen this happen before... I'm running a Hornet with TBLE-02S on stock Mabuchi 540S motor, and Tornado 3300 racing pack - which is where it gets weird! I have two identical batteries, one of which runs the model perfectly (I called it Number 2) - the other battery (#1) runs freely when you hold the car in the air, forward and back, but put it down and the car cuts out pretty much immediately. It will stutter and beep, flash the red LED and then stop responding. So, obvious thing is to check the voltage - yesterday the multimeter showed 7.84V for battery 2 which runs perfectly, and 8.06V for the 'bad one' ?? Contacts are good as the bad battery runs the wheels freely in air... howcome the ESC seems to bail immediately when any load is applied, and why to only one battery??? Have a great weekend! Share this post Link to post Share on other sites
sosidge 624 Posted May 7, 2022 Although the resting voltages don't seem that low, always do these tests with a fully charged battery, and remember that it is quite common for cheap NiMH batteries like this to "false peak" when used with cheap chargers, you would expect them to be warm to the touch when they come off the charger. I would give the contacts a good clean anyway, and check that the pins are a tight fit. Even if they look good, they might not be a very robust contact under load. Ideally you would swap the connectors for something like a Deans or an XT60 because Tamiya connectors are not good in the first place. Also the TBLE has a low voltage cutoff which is not required for NiMH. I'm not sure if it can be switched off or not. Also it could simply be that you have weak cell(s) in one of the packs which read a good voltage at rest but dips down very low under load. NiMH batteries don't have the performance of LiPos and don't have a good lifespan either. Fine for getting started but no more than that. 1 Share this post Link to post Share on other sites
cobalt 19 Posted May 7, 2022 Hi BigLion I had the same problem with my LunchBox+TBLE02S i turned off the low-volatge cut off and the problem went away.(using 5000 nimh pack) Things to look out for: My nimh is starting to die, so under load, the voltage maybe drops too much and may have activated the low voltage cut-off. I also plugged a "glitch buster" in the spare radio channel see link below: https://www.spektrumrc.com/Products/Default.aspx?ProdID=SPM1600 Cheers! 1 Share this post Link to post Share on other sites
BigLion 4 Posted May 7, 2022 1 hour ago, sosidge said: Although the resting voltages don't seem that low, always do these tests with a fully charged battery, and remember that it is quite common for cheap NiMH batteries like this to "false peak" when used with cheap chargers, you would expect them to be warm to the touch when they come off the charger. I would give the contacts a good clean anyway, and check that the pins are a tight fit. Even if they look good, they might not be a very robust contact under load. Ideally you would swap the connectors for something like a Deans or an XT60 because Tamiya connectors are not good in the first place. Also the TBLE has a low voltage cutoff which is not required for NiMH. I'm not sure if it can be switched off or not. Also it could simply be that you have weak cell(s) in one of the packs which read a good voltage at rest but dips down very low under load. NiMH batteries don't have the performance of LiPos and don't have a good lifespan either. Fine for getting started but no more than that. True - I've got a Fusion NX86 charger which runs at 0.5A, 1.0, 2.0, 3.5 and 5A - seems to charge very quickly and the batteries aren't hot when the unit shows the green LED for fully charged... which current would be recommended? Very interesting about weak cells - that's a good appraisal right there - and I just now tried the same pack with my Midnight Pumpkin - same issue! Looks like I have an excuse to go to the hobby store! 1 Share this post Link to post Share on other sites
BigLion 4 Posted May 7, 2022 28 minutes ago, cobalt said: Hi BigLion I had the same problem with my LunchBox+TBLE02S i turned off the low-volatge cut off and the problem went away.(using 5000 nimh pack) Things to look out for: My nimh is starting to die, so under load, the voltage maybe drops too much and may have activated the low voltage cut-off. I also plugged a "glitch buster" in the spare radio channel see link below: https://www.spektrumrc.com/Products/Default.aspx?ProdID=SPM1600 Cheers! Thanks brother! I'll give that a whirl cos I noticed the Hornet has a perfect spot for a GoPro mount... 2 cars, 2 cameras - just sorting out the drone and we'll be all set! 2 Share this post Link to post Share on other sites
sosidge 624 Posted May 7, 2022 Usually fast charge at 1c, so 3.3a for a 3300mAh pack. This would take around 1 hour to charge a battery that is completely flat. 1 Share this post Link to post Share on other sites
Busdriver 6209 Posted May 7, 2022 You must be new as you just said you needed an excuse to go to a model store. Rule 1 of TC no excuse needed😆 2 1 2 Share this post Link to post Share on other sites
DK308 219 Posted May 9, 2022 As was suggested above, charge your pack at 1C or as close to - i.e 3 or 3.5 ah if possible. Now before you do that, drain the battery. Put the car on a stand, or remove the wheels. Then set your trim so that it just runs like 1/4 throttle. Let it run down until cut-off. Then time your charging and see how long it takes. If you charge at 3 ah and it puts about 3 ah into your battery, it should take about 1 hour. If you have a charger that can cycle the battery, do that 3-4 times. What charger do you have? If all you have is a wall wart, start there and get a proper charger. It does not have to be a big deal, just something reliable and dependable. I suggest this. Have had mine for years and it never fails to do things right. I have bigger, faster and more advanced chargers, but this is a great little workhorse. https://www.skyrc.com/iMAX_B6AC_V2_Charger Share this post Link to post Share on other sites
BigLion 4 Posted May 9, 2022 On 5/7/2022 at 8:11 PM, Busdriver said: You must be new as you just said you needed an excuse to go to a model store. Rule 1 of TC no excuse needed😆 Ah, those heady days when my Dad took me down to Blunts models in Mill Hill every weekend (he was working on his collection of boats, and my brother flew areo models).... all the Tamiyas were on the 'top shelf' Share this post Link to post Share on other sites
BigLion 4 Posted May 9, 2022 I got this charger with the kit bundle... any good?? Convenient that it has 12V charging so I can use the trailer socket while I'm out I have just the stand to discharge the battery with the wheels on - giving it a crack now Share this post Link to post Share on other sites
DK308 219 Posted May 9, 2022 That charger is perfectly fine. Discharge the battery and see how long it takes to charge at 3.5 ah. Share this post Link to post Share on other sites
BigLion 4 Posted May 10, 2022 Wow - Thank you guys for helping out with this - the battery is now sorted! I put the Hornet up on the box and used the throttle trim to run the run the battery completely out (I stopped when it started stuttering the ECS for fear of damaging it). The multimeter was showing 6.76V. Charging still only took less than 20 minutes on 3.5A, but the difference was that the battery got really hot! The Hornet took off like a shot and didn't stutter at slow speeds. Looks like problem solved! So my takeaway is that I need to fully discharge the battery to get a decent charge - but should you store them fully charged or fully discharged?? Thanks Sosidge, DK308, Busdriver and Cobalt Time to suss out the drone situation - then we'll be in business! Share this post Link to post Share on other sites
skinned 134 Posted May 10, 2022 Storage charge is I believe 3.86v...each cell... Share this post Link to post Share on other sites
alvinlwh 5895 Posted May 10, 2022 47 minutes ago, BigLion said: should you store them fully charged or fully discharged?? Whatever suits you. NiMHs do not have a preference. https://www.powerstream.com/Storage.htm#:~:text=Either fully charged or discharged,or three charge %2F discharge cycles. Share this post Link to post Share on other sites
alvinlwh 5895 Posted May 10, 2022 38 minutes ago, skinned said: Storage charge is I believe 3.86v...each cell... 3.86v per cell is 3 times the rating of the cells in his pack and will probably blow them up. Also, don't think it is necessary to storage charge NiMHs. Share this post Link to post Share on other sites
BigLion 4 Posted May 10, 2022 Great advice guys - thank you! I just fully discharged 'battery #2' and it took a hella long time - I used the Pumpkin with the wheels off and it ran for more than an hour Some sources are stating you should charge the battery before you store it, otherwise it will 'over-discharge' - my drone instructions said to do this, too - glad there's not really a best way as I'm not sure how likely I am to stick to the routine every time - wherever I run my cars they always get dusty so I gotta wash them down each time! Share this post Link to post Share on other sites
SlideWRX 785 Posted May 10, 2022 5 hours ago, BigLion said: Charging still only took less than 20 minutes on 3.5A, but the difference was that the battery got really hot! The Hornet took off like a shot and didn't stutter at slow speeds. Looks like problem solved! That sounds quick to get the full 3300 mAh of the battery. I'm guessing you got ~1500 mAh, which will get the car running as desired, however it will just run out of juice more quickly than expected for a 3300 mAh battery. If you do get a better charger, some charge/discharge cycles and re-peak cycles may get it to full-ish charge. Share this post Link to post Share on other sites
skinned 134 Posted May 10, 2022 5 hours ago, alvinlwh said: 3.86v per cell is 3 times the rating of the cells in his pack and will probably blow them up. Also, don't think it is necessary to storage charge NiMHs. My bad..was thinking lipos... Share this post Link to post Share on other sites
DK308 219 Posted May 10, 2022 You're most welcome. I take it that your packs are new correct? New NiMh packs likes to be cycled when new. I don't believe your charger has a cycle program. Just go out at drive the car a few times. Run it down and recharge. Now when you charge these new packs, lower the amps a bit. Charge at 1 ah instead of 3.5 ah for the first 6-7 times. Charging will take longer, but hey. 1 Share this post Link to post Share on other sites
El Gecko 1344 Posted May 11, 2022 23 hours ago, DK308 said: You're most welcome. I take it that your packs are new correct? New NiMh packs likes to be cycled when new. I don't believe your charger has a cycle program. Just go out at drive the car a few times. Run it down and recharge. Now when you charge these new packs, lower the amps a bit. Charge at 1 ah instead of 3.5 ah for the first 6-7 times. Charging will take longer, but hey. I would second this advice. I've been charging mine at 1Ah for the last year or so, and they haven't had any noticeable decrease in performance or capacity. In fact a slight increase from when I was charging at 3-4Ah all the time. @BigLion Another thing to check if one battery has issues and the other doesn't, is the Tamiya battery connectors themselves. Especially the female connector on the charger. I have to periodically tighten up the contacts on mine because they loosen up a little every time I plug or unplug a battery. And I typically store my NiMHs fully charged. They don't lose much over time, so it's nice to have them charged up and ready to go whenever. If I want to be 100% sure they're topped off, they just need a quick jolt at 3-4Ah before I take them out for a run. The top-off only takes 10-20mins per battery, just enough to run through a full charge cycle. Share this post Link to post Share on other sites
