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Hi guys

After not using my hotshot for over a year my little used Orion 4500 battery has died.

I did store it fully charged.

I,ve just ordered a new hpi plazma 3300 from modelsport as they have excellent reviews.

In order to keep my battery in top condition I have a few questions.

1.will my new battery need charging when I receive it?

2.which charge rate shall I use for the first charge?My charger is a fusion vector NX85 which can charge at 0.5a 1a 2a 3.5a and 5a

3.for normal charging shall i use 2a or will 3.5 be ok?

4.how to store if not using for a long period?

I,ve looked on line and there are lots of different methods and answers.

Cheers Karl

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I assume your Orion 4500mAh is a NiMH, isn't it? If you haven't done yet, please try discharging and re-charging the battery multiple times. If you're lucky, you might get it back in working condition.

On your questions:

1. Yes, that's the case with NiMH and NiCd. They discharge themselves pretty fast over time when not in use.

2. No need to make the "first" charge different from regular charging. I never encountered problems charging on 2C. You should be fine with 5A.

3. See 2.

4. I just store my LiPos and NiMHs fully charged in a box. After a long period of not using them, they need to be recharged anyway. Once I had problems with NiMHs getting "lazy", I used the discharge-charge method above.

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Hi Greg

Yeah my battery is the Orion 4500 nimh.

I,ve tried running it right down and recharging it a few times and if anything it's loosing more power.

I have a Carson 2700 hump battery out of my unbuilt buggy champ and that works fine,plenty off power after being in storage so its deffo the battery.

About charging I thought you was supposed to charge at 1C or less for nimh?

Is it best to avoid trickle charging as well?

Cheers Karl

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Well, that's just how I do it. I think some of the R/C racers of this forum will let you know how they had been treating their Nickel packs in the past to get most performance out of them.

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Greg, I promise I'm not trying to be rude, but your tips for storage are bad. Storing batteries fully charged is the very reason they are losing their voltage over short periods of time. The more full a battery is when placed in storage, the quicker it will lose it's voltage. Nimh is by the worst culprit for loosing it's voltage in storage (no matter what the storage voltage). Typically you discharge them on a equalizer discharging individual cells down to 0.9v (they spring back to 1.2v resting) before putting them away. Then take them out every month or so to verify resting voltage. If you don't have an equalizer, then it's usually best to store them empty after their last run. The most important thing to remember with Nimh is If any individual cell's resting voltage drops below 0.9v, that cell will be irreparably damaged (it grows crystals inside and the internal resistance goes through the roof). You can usually cycle them back to some sort of useful state, but they will NEVER perform how they did when new.

For Lipo, a decent quality cell wants to be stored at 3.7v per cell. This is somewhere around the halfway point. Most lipo chargers have a storage mode that automatically raises or drops each individual cell to this exact point. Once complete, you put the cell away till the next time you want to use it. They can be stored this way for years. I know this because I have stored several packs for years this way (Orion & Intellect). Pulling these packs out of storage after a year and putting them back on the storage charger results in only a couple milliamps being put back into them before reaching the optimum. When it's time to run them, simply put them on the balance charger at 1C, and you're ready to go. All my packs are still running strong and some of them are 6 years old.

As for charging, the higher the amp rate you charge your Nimh packs, the more powerful your run will be. Typically Nimh are charged at 5amps on your basic charger. Nimh should always be run straight off the charger, even if they are hot. If you charge them well before your run, the voltage will have quickly dropped and the pack will seem flat and lifeless.

For lipo, charging is always safe on a balance charger at 1C. You can charger well before your run and still get fantastic punch and run-time. They stay cool due to the charging style and as a result, live long & happy lives. There really is nothing better than lipo right now in RC. Nimh is extremely high maintenance, low performance and short lived in comparison.

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Very interesting read 94eg!! You've just confirmed why I killed by 2 NiMhs through completely discharging them repeatedly. Whoops!

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After racing high performance nimh, I can honestly say that I ABHOR them. I had to buy high amp discharges, multiple equalizers, resistance testers, expensive (at the time) high-amp computerized delta peak chargers, and high-watt soldering irons. And even with all that equipment, $50+ matched packs would loose their performance within two months.

:wacko:

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Hi 94eg

Thanks for the very detailed battery info.

As I don't have an equaliser if I run my battery down after use for storage will that not be close to or below 0.9v per cell which will ruin the battery as you have mentioned?

After use what kind of voltage will be left when the car becomes very slow?

Without a charger which shows the battery voltage how long and often shall I charge the battery to keep from falling below 0.9v?

Cheers all

Karl

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There is a difference between voltage under load and voltage at rest. It's the resting voltage that cannot be allowed to drop below 0.9v (per cell). As soon as you stop putting a load on the pack, the voltage instantly springs back up to 1.2v (per cell) even though there is no more power left inside. This is why it's called "nominal voltage". It's the voltage rating of your pack (at rest) when it's completely spent.

When the pack dumps and you loose forward power, each cell will be at about 1.20v resting voltage. That means a 6-cell packs resting voltage should measure 7.2v once you unplug it. No worries about killing your pack if you stop driving as soon as the car slows down. A sharp drop in performance is the first sign that one or more of your cells is spent. You don't want to keep driving as your weaker cells will get over-discharged, and become permanently damaged (lower voltage, lower runtime & higher IR).

As for your third question, it's anybody's guess. Each pack is different, and in fact each individual cell is different. This is why equalizers were necessary for safe discharge. Maintaining high performance packs was such a chore in your off time that companies like Tekin started selling devices called the Battery Nurse. It was essentially a briefcase that you left plugged in 24/7 so it could monitor and maintain your packs healthy resting voltage for extended periods. Talk about crazy!

tektt1435.jpg

img_0608.jpg

If I were you (and you refuse to switch to lipo), I would:

- run my packs till they dump

- check individual cell resting voltage (should be about 1.2v each)

- store them

- pop them out once a week and check voltage

- if any cell is approaching 0.90v, charge it for 1 minute on lowest amperage

- Then get sick of the BS and switch to lipo

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Hi mate

Looks like I need to get myself a new charger,lipo charging sack and a lipo battery.

Keeping nimh,s in top condition sounds like hard work.

For my hotshot which has a tamiya BZ super stock motor and 20 turn Mtroniks lipo approved ESC what sort off lipo should I be looking at?

Cheers Karl

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I've run an oriion 2400 in my Hotshot a couple times. I think I also fit an Intellect 3800/35c. Both of these were bullet type hardcase lipos. I've really had good luck with intellect, so I would probably suggest starting with a shot-gun style Intellect. I think their current shotgun packs are up to 4800mah now with Tamiya or Deans plugs. They even have a 3800 with bullet plugs, but those are more risky (reverse polarity protection in your ESC is important).

I cannot vouch for this seller, but they have a lot of options for intellect so you can see them:

http://www.rcstation.com/newshop/catalog/index.php?manufacturers_id=12&sort=2d&page=1

Even if they are not a perfect fit in old chassis, it's more than worth making modifications to runners in order to use these batteries. WAY more punch, longer & more consistent runtimes, and ease of ownership if your charger has a storage setting. Fitting the lipos in the hotshot is not tough work. The trick is modifying the side bars that hold the pack by the ends to allow more length. There is plenty of room inside the chassis otherwise.

BTW: For bashing, buying more low-capacity packs can be better bang for your buck than fewer high capacity packs.

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Will a lipo with a tamiya plug be ok for my set up as most lipo,s seem to have a deans type plug.

Also what about 2s and 3s and c rating?

Which would be best for my set up?

The battery SteveU30 listed looks like it will fit with no problems.

Does the same rule apply to nimh about lower capacity batteries give more performance than higher capacity?

Cheers again

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Switching to deans would be better, but a Tamiya connector should be able to handle a BZ on lipo. I run a tamiya connector in mine with an RZ with lipo, and I thermaled the ESC without any problems at the connector.

Definitely stick with 2 cell (7.4v). You have to make sure your ESC is rated for 3 cell, and that kind of power will likely make short work of your hotshot's drivetrain.

C rating relates the quality of the cells and their ability to give up their energy effeicently. A higher C rate is better as it typically means you will have better punch through lower internal resistance. But it's definitely not an absolutely necessity for bashing with only a BZ motor. Milliamps is the most important factor if runtime is your main concern. Don't spend a fortune on a low milliamp battery just to get an 80c or 100c rating. You only need enough C to keep pace with your ESC. Here is how you figure that out:

- 120amp ESC

- 4000mah battery (4000mah = 4amps)

120 / 4 = 30

This means 4000mah/30c will keep pace with your ESC.

- 60amp ESC

- 3000mah battery (3amps)

60 / 3 = 20

This means 3000mah/20c will keep up

- 120amp ESC

- 5800mah battery (5.8amps)

120 / 5.8 = ~21

This means 5800mah/25c will keep up

As for capacity vs performance, I would say no your rule doesn't apply. I also don't think that rule ever really applied when comparing high performance matched racing packs. Higher capacity cells (all else being equal) will almost always have a higher average voltage throughout their entire runtime. But since lipo's are much more consistent than nimh, almost any brand pack (even the cheapo's) will have amazing output. Also since lipos are much more efficient, they will not waste as much of their energy creating heat, which also equates to better power and runtime.

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Really useful info 94eg, thanks.

Just got to decide which Lipo to get next. The VapexTech one I have has the wires and balance leads in an awkward position for most of my cars battery clips, but it has the correct shape for many of the oval battery holes in my older cars. A square Lipo hardcase has the wires coming out of the top which would suit many more applications, but the shape would stop me using it in quite a few of my cars...

Decisions, decisions!

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Like I said though, more batteries of lower milliamps can be a lot better than one battery of higher milliamps. Having different packs of different shapes on hand is great for taking a trip out to the park. And having a 1 specific pack for each of your cars is the absolute ideal. You simply charge them all before you leave (or even the night before), and then you have several cars ready to run as soon as you get there. If you get bored of one, just switch on the next. If one pack reaches cutoff, switch on the next. If you break one, just switch on the next. It's definitely the best method that I've found to enjoy the bashing hobby.

If you can't afford a new charger AND several batteries, then I would start off purchasing a single pack for the car you want to run the most. Some cars have a hard time fitting stick-pack lipos (the Hotshot is not one), so you may need to consult the thread about that subject when deciding.

Also be aware of lipo low voltage cutoffs. You cannot run these packs dead without damaging them permanently. Cheapie lipo alarms that plug into balance taps of the pack are effective when running vintage electronics without LVC. But the lower the milliamps of the pack, the more the voltage will sag under load and the more often you will hear random false alarms well before the pack is spent. My Dynastorm with Acto 14T makes the lipo alarm go off under load when I run the Orion 2400mah, yet the pack is nowhere near spent. Of course once you let off the throttle voltage springs back up and the alarm shuts off.

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Useful to know.

I have invested in several L-V alarms for my Tamiya cars without LVC. I have a Blackfoot Xtreme which I use the most as the clearance is great for longer grass, this runs a 3500kv brushless and I only managed to run my 3300mAh pack down once, after about 25 minutes which is more than enough run time for me to get bored / break something. I did run it too low once - the LVC on the ESC is disabled as a defualt setting (genius of Speed Passion to do that) and it dropped to 2.8v per cell. Fortunately it seems to have had no ill-effect, I balance charged the battery the very next morning.

I bit the bullet and bought another Vapex Tech 4000mAh battery as it has the oval sides again and different discharge leads supplied with it. I won £83 on the Lottery so that's my little treat (£26.95 delivered for anyone interested). The Mrs wants her nails done...That's costing me £50 of my winnings :(

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....The Mrs wants her nails done...That's costing me £50 of my winnings :(

LOL! Too bad that won't last as long as your lipos. ;)

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Hi guys

My new hpi 3300 battery arrived yesterday so tonight I charged it prior to use as it was completely flat when I received it.

I,m very happy with how my hotshot now goes now my BZ motor is getting enough juice

I ran it in my back garden after I cut the grass and gave it a very light watering and I had plenty off fun doin dounuts and 4 wheel drifts. (Its running on Tarmac spec tyres at the moment so not much grip on damp short grass)when I got grip on the path it now fly,s compared to using my old higher capacity battery.

I,ll deffo be looking to goin lipo soon especially if I get more speed and better run times and easier to maintain batteries.

Thanks for the advice karl

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This apperas to be the right thread to ask this question. I have some NOS Tamiya hump batteries, still in boxes. I asume them to be old, should I assume they'll be usable or are they destined for a life of leasure sitting on show in shelf queens.

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This apperas to be the right thread to ask this question. I have some NOS Tamiya hump batteries, still in boxes. I asume them to be old, should I assume they'll be usable or are they destined for a life of leasure sitting on show in shelf queens.  

There's every chance they're usable, you'll just have to charge them and find out. If they're duff though you could always do this: http://www.tamiyaclub.com/showroom_model.asp?cid=122994&id=29487

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good idea, I have 3-4 'old' ones that I know are nutted. Might just repack with nicads, lipo's like science fiction to an old fossil like me. I got a lipo for my wheeler 2 but haven't been game to try it. :huh:

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It's just a battery. Get over it. ;)

But seriously, if you have a lipo charger, there is no reason not to use it. The cruddiest lipo will absolutely murder the best nicad.

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good idea, I have 3-4 'old' ones that I know are nutted. Might just repack with nicads, lipo's like science fiction to an old fossil like me. I got a lipo for my wheeler 2 but haven't been game to try it. :huh:

You really should try it, what's holding you back exactly?

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