Taranis Charger (need help with reducing Amperage)

LTMNO · Post by **LTMNO** » Wed May 21, 2014 6:21 pm

Hello All,
I bought a Taranis a while back and haven't used it until today. I upgraded the batter to 2000mAh and decided to charge it.
Unfortunately I don't have a charger as I neglected to order one of those but I do have a few power adapters that AC to DC.
The one that works right now is 12V 250mAh charger but that will take longer.
I also have a 12V 1A charger but from what I read is that the Taranis wants .5A at 12V.
So, the question.....

How do I reduce the Current from 1A to .5A?
From what I have read here :
http://www.instructables.com/answers/ho ... the-volta/

I need to put Resistance on the power line to bring down the current.
I am not an electrician but if anyone can help out on this, it will be greatly appreciated.

You might ask, why not just buy the right charger?
I will, but in the mean time I need to charge my Taranis.

Thanks!

Post by **Kilrah** » Wed May 21, 2014 6:43 pm

The amp rating on a power supply is how much it is able to give. The radio will only take what it needs, so you have nothing to do.

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Daedalus66 · Post by **Daedalus66** » Wed May 21, 2014 7:30 pm

Your only problem is with the 250 mA power supply, which is inadequate to meet the requirements of the internal charger and might overheat or supply reduced voltage. Using an oversize power supply doesn't matter, as the charger will only use what it requires.

LTMNO · Post by **LTMNO** » Thu May 22, 2014 11:47 am

Kilrah wrote:The amp rating on a power supply is how much it is able to give. The radio will only take what it needs, so you have nothing to do.

Sent via mobile

Thanks, that is great to hear... cheers!

LTMNO · Post by **LTMNO** » Thu May 22, 2014 11:47 am

Daedalus66 wrote:Your only problem is with the 250 mA power supply, which is inadequate to meet the requirements of the internal charger and might overheat or supply reduced voltage. Using an oversize power supply doesn't matter, as the charger will only use what it requires.

Thanks, understood.. I won't be using that anymore.

Cheers!

Daedalus66 · Post by **Daedalus66** » Thu May 22, 2014 3:31 pm

One more thing, though you probably understand this by now, you MUST not plug a charger into the Taranis. The charger is built in and only needs a 12v supply to feed it.

LTMNO · Post by **LTMNO** » Thu May 22, 2014 6:24 pm

Hello, I have a 12v switching power supply at @2A.
It is just a power supply.
What is the full charge on the Taranis.. it stops at 8V for me.
Is that correct?

Helle · Post by **Helle** » Thu May 22, 2014 8:09 pm

Hy,

the Charger for 6 cells NiMH is in theTaranis
8V/6 Cells=1,33V that is ok

Helle

Post by **ShowMaster** » Fri May 23, 2014 2:55 pm

As long as the ps under load is less than 14v. Something like 13.5 I think was posted by MikeB.
The charger circuit components have a max voltage rating.
It was posted I believe, that the charge circuit for a 6 cell Nimh, runs at 400-450ma max. Any current rating over this is ok as long as the voltage is in the 12-13.5 range.
As stated, never use a smart charger, just a 12v source.

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LTMNO · Post by **LTMNO** » Fri May 23, 2014 11:59 pm

Thanks to all.

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cparsons · Post by **cparsons** » Mon Jun 02, 2014 2:16 pm

I was thinking about making up a lead to charge a Taranis in the car (via the cigarette lighter socket) but the voltage with the car running can be close to or over 14v IIRC?

Good idea or not?

Chris

Post by **jhsa** » Mon Jun 02, 2014 2:21 pm

To charge in the car? No, not a good idea.. I wouldn't..

https://www.youtube.com/watch?v=yc8NTkUKJ8k

Post by **Kilrah** » Mon Jun 02, 2014 2:32 pm

NiMH.

Mike made a post one day about the max input voltage, you might want to search for it...

cparsons · Post by **cparsons** » Mon Jun 02, 2014 2:33 pm

I was talking about charging the NiMh battery not a LiPo...using the existing internal charger

Sorry Kilrah our posts crossed - I presume you were saying the same thing?

cparsons · Post by **cparsons** » Mon Jun 02, 2014 2:38 pm

Yes, I read an earlier post by ShowMaster about the max input voltage being 13.5v which prompted the question?

I am wondering show much the standard 12v power supply that comes with the Taranis varies? How well regulated it is, in other words?

Chris

Post by **jhsa** » Mon Jun 02, 2014 2:46 pm

cparsons wrote:I was talking about charging the NiMh battery not a LiPo...using the existing internal charger

Sorry Kilrah our posts crossed - I presume you were saying the same thing?

sorry.. There was someone talking about charging a lipo or life the other day and I obviously misread your post.

João

cparsons · Post by **cparsons** » Mon Jun 02, 2014 2:55 pm

No problem - I have done a bit of looking around and someone else suggested a voltage limiter - I found one on FleaBay

http://www.ebay.co.uk/itm/New-Durable-M ... 4897.l5663

which is pretty inexpensive (I am in the UK)

Another alternative of course is to get a spare NiMh battery and charge it directly with my smart charger (outside the tx) which can be run directly from the car. I use this to charge my LiPo batteries for the quadcopter (carefully!) but the thought of being able to use a simple lead to top off the tx battery appealed.

I guess if the 2000mAh battery lasts > 15 hours perhaps it's not worth worrying about!

Chris

Post by **ShowMaster** » Mon Jun 02, 2014 5:05 pm

Some ideas.
How about using a fully charged 3 cell lipo plugged into your Taranis while you drive to the field? Recharge the lipo later.
I also bought several mini buck regulators for $2 free shipping from eBay. 16 volts in max, adjustable down to a lower voltage. 1.5A constant, the Taranis needs 450ma max I believe.
If you're using the 6cell Nimh Taranis pack, you should have enough headroom between 14v and 12 to maintain the charge rate. I also believe the Taranis charger can run a volt or so lower than 12 in to charge normally.
So maybe set the regulator for 11-11.5v out to give more headroom when your car is at idle or 13v?
MikeB originally posted the min and max he felt the Taranis charger could work at. A search should find these values or maybe he'll post them again.

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Helle · Post by **Helle** » Mon Jun 02, 2014 5:50 pm

hy,

what about this one
http://cgi.ebay.de/ws/eBayISAPI.dll?Vie ... ink:top:de

http://www.ebay.de/itm/7-4v-11-1v-LiPo- ... 19ed526464

http://www.ebay.de/itm/Turnigy-12v-2-3S ... 1e8b482492

Helle

Post by **ShowMaster** » Mon Jun 02, 2014 6:28 pm

NO! The Taranis charger is already a "smart" Nimh charger. It only wants to see 12vdc (polarity not critical I've read).
You can't feed a smart charger with another smart charger. If the one you posted are used and think the load requires 20v, it makes it and feed it to the charge jack. This has already fried several or more Taranis TXs.

11.5-13.5 Vdc seems to be the range with 12v actually desired. I did read AC may work but I'm not going to test that on mine.
My simple answer to all my portable 12 v charging.
Personally I carry a 14A gel cell in a home made tip proof small case. I use it for everything requiring 12vdc in my highlander. All power goes off with the ignition switch and I use it for cell phone, ham gear, and anything RC requiring 12 v for charging. I charge it every few weeks and it lives in my car in earthquake LA.
It has connectors to mate with home electronics I use.
No spill, normally no fire hazard, internal fuse, charge when the meter says 11.5. I can charge on the go, or on the RC bench, no car lipo charging however!
Most jump start boxes are all fluff and plastic, large case footprint, 7-10 A battery for $50/60+. For $40 I get a 14A battery in a small light footprint box.

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Post by **ShowMaster** » Mon Jun 02, 2014 10:20 pm

Another option. I just picked this up from All Electronics locally.
9-18vdc in 12v @450Ma out. Cost $4.95. I bought it to try it out. Let's see if it can interface and supply the current the Taranis charger needs. I'll scope it and maybe add a large cap on the output.
My thought it also add a 1amp diode (1n4003/100 for $3) in series with the input as a reverse voltage protection. I never make a mistake but I could I'm told.

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Post by **ShowMaster** » Tue Jun 03, 2014 3:17 am

In case you're following my progress, here is an update.
This is a dual + and - 12 volt output at .5A max each output. I could use it as a 24 volt out @ 1 amp and regulate it down to 12v @ 1 amp max if my math is correct.
A quick test of the Taranis internal charger gave me these readings.

Here's what I measured with the HK 2400ma and original Taranis 800ma pack. Both are 6 cell packs. Both packs were charged a week ago but I didn't measure the battery voltage, just charging.
I monitored the ps voltage into the Taranis charge jack and the current going into the pack by having my meter is series with the packs +lead.
Input 11.5 (min voltage for charging.)
Charging 200ma.
12v input 270-280ma charging.
13v input 380ma
13.5 input 380ma
No change from 13 to 13.5.
I'll be using the 12v output into the charger. I should be good with any voltage my alternator puts out, or my car at rest. The input and output are isolated.
The .5 amp max on the single output of the DC to DC converter should be ok for my purpose.
These DC to DC converters are out there surplus at various prices. I've paid $3 to $5 for them so far for projects.

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Post by **MikeB** » Tue Jun 03, 2014 8:49 am

You would get 24V, but still at 0.5A.

Mike.

Post by **jhsa** » Tue Jun 03, 2014 9:11 am

Would something like this work?

http://www.ebay.com/itm/New-DC-DC-LM259 ... 58a6d193ea

João

Helle · Post by **Helle** » Tue Jun 03, 2014 10:40 am

Hy<

you need a real charge not only a DC-DC converter and voltage protector

Helle

Post by **ShowMaster** » Tue Jun 03, 2014 2:29 pm

MikeB wrote:You would get 24V, but still at 0.5A.

Mike.

What, my fuzzy math is wrong, again!
Hi Mike. Of course dumb me, I'm putting the 2 outputs in series to get the 24v. The currents don't double in series. The module is capable of 12 watts total.
Was I in the ball park on the charger requirements? I did those test awhile ago with batteries not at end of their discharge.
I don't know what the Taranis chargers max charge current draw is. In any case the concept is ok and there are higher current surplus DC to DC converters around. This is more of a R&D project to show another constant 12v DC source that will work on a running auto alternator.
Using a fully charged 3 cell lipo seems to work in a pinch for a short recharge boost. Just plug a lipo cell meter in the balance port to make sure you don't drain your lipo while doing a short recharge with this method.

FYI, while discussing Taranis tx charging. Off the main topic but it is used to charge my TXs.

For those that are members of an organized RC club or group, a serious RC power source. Not practical for get together flying.
6 weeks ago at my local RC field,
I added another 40 amps of solar panels to our 60A we had. This in turn charges a 20 battery 100A 12v battery bank (2000A). This is backed up by a 5Kw generator and 100A charger.
I have a wireless weather system that reports the Wx conditions every 5 min 24/7 as well as battery voltage and storage container temps.
Soon I'll have the ability to remotely control generator from home.
More for winter months when the solar charging system suffers from short days. Electric flyers are multiplying so fast that the charging system can't keep up in the winter weekends.

I still like trying new 12v charging options, the purpose of this topic. Either 12 volts into the Taranis charger, or 12v for a smart charger for external tx battery charging.

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Post by **ShowMaster** » Tue Jun 03, 2014 2:38 pm

jhsa wrote:Would something like this work?

http://www.ebay.com/itm/New-DC-DC-LM259 ... 58a6d193ea

João

I have several and should try one. It's all about headroom. It has to give me 12v at 14.2 and be passive or greater than 11.5 when the auto is at idol. I'm not sure if the Taranis charger would be confused by the fluctuation of the input voltage if it swings a lot while driving?
Easy enough to test when I have time.
Thanks Joao for the idea.

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Post by **ShowMaster** » Tue Jun 03, 2014 2:44 pm

Helle wrote:Hy<

you need a real charge not only a DC-DC converter and voltage protector

Helle

Thank you for your comment. The idea here is the Taranis charger is a real Nimh smart charger already. It does require a 12v @.5 amp voltage source to work. Auto alternators can output 14.2 volts while your driving, too high for the Taranis charger. 13.5 max seems to be the safe value.
So trying to charge your Taranis from you auto while driving to the flying site could do damage.

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Post by **ShowMaster** » Thu Jun 05, 2014 1:50 pm

Under load charging, my DC to DC converter output drops to 11.8v with 10-15.5 volts input. Good enough to prove it works as a car charger source for the Taranis.
I'm not sure I'll need to use it, but I'll finish putting in a box with cables and add it to my electric charging accessories.
For $5 and some cables it does solve the original topic problem as one option.
On to other projects.
SM

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