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berman

Another Lipo Question...

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I have just gone LiPo (Yay! finally) on my sand scorcher.

I just bought a couple of Turnigy 1800mah batteries and am currently charging the second pack.

The first pack got to 760mah and peaked, is this normal? I take it that because you cant discharge these very much that they dont take much mah to get to full charge?

Also I have one of the generic two line (screen) four button multi chargers (i.e, Imax B6/Hyperion/etc), just before finishing entering the details and it starts charging it comes up with R:SER S:SER ENTER CONFIRM/ STOP CANCEL or something to that effect (cant remember), what is this? as I cant find my manual.

I also have concerns about hearing the lipo alarm inside the sand scorchers sealed radio box... :lol:

Any help greatly appreciated!

Cheers

Oh pics, everybody loves pics :)

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...The first pack got to 760mah and peaked, is this normal? ...

STOP WHAT YOU'RE DOING. YOU DO NOT PEAK CHARGE A LIPO!!!

What charger do you have? We need more information than "Also I have one of the generic two line (screen) four button multi chargers (i.e, Imax B6/Hyperion/etc)"

Sorry if I sound like I'm lecturing you but I don't want you setting your house on fire.

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I think it's fine stu, I think he's just using "peaked" by habit as he said he got the "R:SER S:SER ENTER CONFIRM/ STOP CANCEL" wich are the chargers way of giving you one last chance to look over the voltage setting - you have to confirm that you have entered the right cell count...

The reason you couldn't get very much charge into the battery is because LiPos doesn't discharge from storage so much and you must not store LiPos fully charged (if your charger has a storage mode, use it after running and top them of before running), they should be stored at about 3,8v / cell

Can't you reroute the LiPo alarm to be on the outside of the radiobox?

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everything DCLXVI said is correct, ive had a b6 and now have a b8 charger, as for the lipo alarms, they are quiet load, failing that you could get one of these there available on ebay for around £8 and actually cut off at the voltage you set, like the novak smart stop but way cheaper, i have a few hobbywing products and find them well made and reliable and these are no different, i have two myself and plan on ordering a few more.

what c rating are your batteries 25c,30c etc, i have some of the 2200 35c turnigy lipo's and find them great for the price.

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Haha cheers guys! I was hoping to get a quick response before I went out and tested these packs, but I got so busy I forget to check back!

Stu. Firstly thank you. You weren't being over the top and I appreciate you going to the trouble of 'being an alarmist', and thinking of my safety first ;)

DXLXVI was on the ball, and I was meaning a full charge. I was being an alarmist by posting this thread as it's better to be safe than sorry and LiPo is new to me.

So cheers for your concern and your post :P

DCLXVI. That's what i wanted to hear thanks. I kind of figured they would be partially charged initially and I am grateful for the confirmation.

Can I leave a Lipo fully charged over night? I have charged both packs intially and the both took about 700ish mah. both have been used and then I have charged one of them for the second time and it took the whole 1800ish mah.

It still has the full charge in it though (woops).

Thanks again for everyones help :)

On a side note, those first two packs, just wow... a ni-cad or ni-mh will never set foot inside my SS again. The rumours are true, once you go lipo you will never go back.

It's given my SS such a kick in the pants, lots more torque, a little bit higher top speed too! To me it's kind of feels like a low power brushless setup in a way.

Anyway I'm hooked! :D

Also thanks guys (and tamiya monkey), the alarm is audible enough, even in the strong winds today. You can tell when the power drops off to keep it close enough to hear it without mistake.

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you can leave them charged, i do it all the time.

i charge all my lipo's the night before i go to the track. saves a boat load of time.

just from habit i change packs more often then needed. i'll run 2 6 minute heats on 1 pack and then 1 8 minute main with another. then i leave them until the next week where i'll top them off again the night before.

i use some bigger (heavier) packs for long practice sessions. i race on 3000 35c turnigy's.

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I was into the habit of fully charging my packs before leaving the track and have not had a problem in 2-3 years.

However, early this year one of the guys at SMC advised that their packs not be stored with a full charge for an extended period. Something about the chemistry in the pack would cause them to loose capacity. "Extended period" was kind of vague, and it might be that I have never had a pack sit for more than 2 weeks has kept me out of trouble here.

These days, if I'm pretty sure I won't be running anything for a week or so, I still fully charge the packs at the end of the day, and then discharge them to 3.7v/cell at 10A.

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Having packs fully charged over night shouldn't pose a problem and I can't really say where how long is to long but LiPos can get damaged from extended storage at full charge...they will become sluggish...

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Thanks again guys, Very grateful for the advice :P

Really happy with these packs, they make my scorcher just sing on the beach :) The packs say dont charge over 2C and I've been charging at 0.8 lol, so I may bump it up just a little, maybe 1.4C.

15-20mins and a bit more pep at just $18USD, really dont know why I left it this long ;)

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I have a dumb question about LI-PO batteries .

Do you need to fully discharge them before re-charging ?.

I ask this because the batteries I brought from Hobbyking came partly charged.

Thanks Stuart.

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You should not discharge them, there's no need...

Also, if you get them belov 3v / cell (6v för a 7,4v pack) they're gonners basically...

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You should not discharge them, there's no need...

Also, if you get them belov 3v / cell (6v för a 7,4v pack) they're gonners basically...

some of the time they can be "brought back from the dead", but it's time consumeing.

you need to charge @ .01 amps until they reach the minimum voltage.

i have a 3s pack that my neighbor ran down to low that i'm going to attempt to bring back for him. i'll post the results.

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Thanks guys :lol:

I guess it was not such a dumb question the only dumb question is the one not asked .

Cheers .

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I use 2 packs of 4000mAh 30C in my 4-5 qualifiers, charging in between. Sometimes I come back and will charge them up and leave them for 2-4 weeks before the next race and they have been fine. I have been using them for 2 years now and the capacity have ben fine so far.

I have noticed that usually, there is about 7.6V left after a 5 minute run ... in a brushless 13.5T setup, and the last time I stored them, I just left them after a race and 3 months later charge them up before a race and they have been good to go ...

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You will find that most of the current crop of lipo chargers have what is called a "storage charge" setting. This will either charge or discharge the pack to a specified resting voltage depending on it's cell count. This is the ideal way to store your batteries. If your charger doesn't have this feature, then simply leave the packs in your bag after your done running them. Don't bother charging them for storage (unless you hit the low voltage cuttoff). They won't self discharge like nickle batteries, and you don't have to worry about them going bad. I've had 4 packs in storage for about 6 or 7 months now, and all their voltages are fine.

BTW: For racing, I always balance charge for ONLY the first charge when pulling the packs out of storage. Every charge thereafter is done with a standard lipo charge (no balancing). The balance charge constantly varies current between each cell which will reduce the punch during the run.

As a final thought: Those lipo alarms really suck. They go off as soon as the pack reaches a low voltage, but they don't stop. Unfortunately lower mah packs see considerable voltage depression under load which causes the alarm to go off very early in the run. My Orion 2400 pack would have the alarm going off in just a couple laps when running my Dyna Storm. Yes the pack still had excellent resting voltage. This device was not very good...

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... Those lipo alarms really suck. They go off as soon as the pack reaches a low voltage, but they don't stop. Unfortunately lower mah packs see considerable voltage depression under load which causes the alarm to go off very early in the run. My Orion 2400 pack would have the alarm going off in just a couple laps when running my Dyna Storm. Yes the pack still had excellent resting voltage. This device was not very good...

I have a Novak cut-off which is good as you know when the battery level is low, as the throttle seems to go intermittent. Downside, they are expensive ... I will need another and so might try the Hobbywing, to see how it goes ... should not be a problem ... and for less than half the price ...

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You will find that most of the current crop of lipo chargers have what is called a "storage charge" setting. This will either charge or discharge the pack to a specified resting voltage depending on it's cell count. This is the ideal way to store your batteries. If your charger doesn't have this feature, then simply leave the packs in your bag after your done running them. Don't bother charging them for storage (unless you hit the low voltage cuttoff). They won't self discharge like nickle batteries, and you don't have to worry about them going bad. I've had 4 packs in storage for about 6 or 7 months now, and all their voltages are fine.

Ditto.

As usual, top advice from 94eg!

;)

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I've been giving mine a full charge and then if I know I'm not going to use them for a while, I've been running them for 2 minutes or so just to take the edge of the full charge (approx 200mah), soley so they aren't stored fully charged. I should check my charger for storage settings.

Can anyone recommend stick style hard pack 7.4v 2S lipo's? So I can run in 'fitted' tamiya chassis's like the king cab/cc01 etc etc? looking for around 3000mah and 30c -ish

only going to buy Lipo from now on, no more nimh or ni-cads for me :P

Cheers

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I can't recommend a pack since I'm not familiar with the chassis, but I can tell you my charger stores batteries at a 7.6v resting voltage for a 2-cell pack. That means they recommend 3.8v per cell for long term storage (more than a week). I know that in racing, they like to store at a lower voltage for short term. Probably somewhere around 7v total. This is supposed to keep internal resistance down. I don't bother with that...

BTW: You will probably have to modify the chassis at least a little no matter what lipo you run. My Dyna Storm required a large notch in the front battery tray to let the pack wires run out the front. This was for a 3200mah yeah racing stick pack. The wires were too thick to make a sharp bend like an old nickle pack does, and the plastic hard case on the lipo was a little longer as well. It fit the tray fine on it's own, but there was simply no room for the wires.

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Sorry I probably need to clarify that a bit. I am looking for a recommendation of a LiPo in the standard sub c 6 cell configuration with the rounded sides and wires out the centre of the end (if possible) so i can fit it in my numerous vintage tamiya chassis's.

Really dont want to modify any of the cars, just looking to run LiPo in all and sundry now that I'm addicted to the power delivery :P

I hear you about the wires, so hornets and grasshoppers etc may be a bit of a challenge.

Cheers for your help :D

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The IP4000 7.4v 2S 25C (100Amp) packs fit alright shape wise into the vintage chassis that need round edge packs. They are (like all the other Li-Po round edge packs) 3mm longer than a Ni-MH, so you do need to modify the battery stop in most cases.

To get the IP4000 into the Grasshopper, I turned the pack around and put the wires to the rear and cut a small slot for the wires in the rear bulkhead of the chassis. The battery plug is now above the rear gearbox. Also makes it easier to unplug the battery without unscrewing the body top off.

They fit no problems into the Fox and Blitzer chassis.

Into plastic tub TA01/02/DF01, I shaved about 2mm off the inside edge of the battery stopper. Once it's all fitted up you can't see that it's been modified.

On the FRP/CF TA01/02/DF01 chassis plates I elongated the mount holes into a slot for the battery ends. You can't see these mods once you fit the battery holder and the undertray (I double sided tape a sheet of lexan under the tourers to protect the bottom of the chassis plate).

On the TA03F with CF chassis I used the quick release battery holder. Where it mounts you add a 3mm alloy spacer. This cannot be seen once fittted.

To get them into the Super Champ took a lot of modifications that you just can't hide.

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Sorry for the late reply, I forgot about this topic. I will try the Intellect pack for the cars that it will fit (perfect for the likes of the king cab chassis etc), but I may possibly just buy the smaller sized soft packs and buy some foam (like in the re-re SRB's) to fit in the hornet/grasshopper as I dont really want to cut anything if I can help it. Thanks for your help Mark. Hey do you have a favoured seller?

Cheers

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