Two battery charger questions.

[Predreadnut]

I've got a few transmitters that require AA sized batteries. I got tired of buying dissposible ones, so I got some rechargeable ones from WalMart. They came with a charger. Well, the charger only charges 4 at a time and it takes forever. Is there a charger that will charge 8 AA batteries at once that is fairly fast. I believe my rechargeable bateries are 2400mah.

[Kmot]

http://www.tigerdirect.com/applications/searchtools/item-details.asp?EdpNo=2415750&Sku=GEN-7000&SRCCODE=GOOGLEBASE&cm_mmc_o=TBBTkwCjCVyBpAgf%20mwzygtCjCVRqCjCVRq

[Shaun Hendricks]

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1098

[Kmot]

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1098
AA rated capacity (500mAh-2600mAh); charging time 3 to 24 hours.

24 hours for a 2600 NiMh doesn't sound like the fast charger he was looking for. :p

[Shaun Hendricks]

I read that differently than you did Tom. I read that as taking forever to charge all 8 batteries because he had to do them 4 at a time.

My preferences in chargers are to provide automated ones with full cycling capability. It charges 10 cells as well and comes with 20 batteries in the package I specc'd. Not bad for the price.

Any battery charger that charges faster than 2 hours will kill your battery lifespan. So 3-24 hours from total dead, sounds about right for a nice charge rate. 3 hours at 500mah is about .16C charge rate. Pretty much optimal for getting full duration out of the cells. It also independently detects delta-v on each charge point and can detect a cell that requires full recycling and charge it separately. Very smart!

All in all, a great deal. It is NOT a 'fast' (kill the battery) charger. It also has enough spare cells that he could plug in new ones galore.

[Kmot]

Shaun, it only charges at a max .2A

The charger I pointed him to costs $15 bucks and he already has the AA's.

I charge my batts at 1C 90% of the time. I don't buy that shortened lifespan rumor. ;)

[Shaun Hendricks]

It's not a rumor. 1C is okay, but not ideal. You might get 90% the lifespan out of the battery which is fine for some folks. It's cheaper in the long run to have MORE batteries switching out in a given task and being charged at the proper rates than it is to have fewer cells fast charging. Thus the recommendation of the charger with the additional cells.

BTW, 1C is relative. A 500mah battery at 1C is .5Amps. If your charger is used to dumping 2Amps, that becomes a 4C charge rate and is destructive to the cell. Even common 1600mah AA's would be damaged by a 2Amp charge rate. A .15 -.2Amp rate is pretty much optimal charging for delta-v for any cell. Your cells reach a true semblance of their mah rating and live their entire projected lifespan.

As for only costing $15, the charger I pointed out is only $15 if you buy it without the batteries. They have faster chargers on that site but again, I can tell you from experience that faster chargers shorten lifespan. I have thrown away all my fast chargers as they have cost me about $100 in batteries not to mention the cost of the chargers, even the smart ones.

The best 'automatic' charger that I have run across is from Ansmann, all that German precision I guess, but as far as I know, they are all made in China or Taiwan. They are not cheap either. You pay $60 for a 4 cell charger! :eek:

[ragss]

Shaun What about a MAHA charger.

[Shaun Hendricks]

Never used one but this one looks good:

http://www.mahaenergy.com/store/viewitem.asp?idproduct=422

It's fully independent and has both fast and slow mode. It's 'fast' mode is only 1Amp which is fine on 2000mah or higher batteries (.5C) but for maximum life, you'd want the slow mode.

Having the option for a fast charge isn't bad, and I agree with Kmot that 1C is not a bad charge rate for a compromise between lifespan and speed of charge, so even 1000mah batteries would be okay on 'fast' but I wouldn't use it on anything less than 1000mah batteries. I'd still probably run everything on a slow charge though. I'm just not in that much of a rush... :D

The LCD screens per each battery are cutesy but just 'glitter'.

Not cheap at $60. If someone gets one, I'd love to hear a review of it. I'd be willing to risk $15 on a charger and if it sucks- oh well. At $60 or more, I'd want it to work GREAT.

[ragss]

My MAHA charger is $69.00 but its a full smart charger. Will do a full cycle discharge/charge on any battery up to 14 volts. You just hook the battery up to it and it figures out what battery you have and does the appropiate charge. You have to tell it weather you want a full cycle or a charge though. Also has a temperature sensor to make sure nothing "bad" is happening.

[Shaun Hendricks]

I've seen those. I have a mostly manual Triton for all my single battery needs but I use more standard chargers for my 'block' style batteries (AAA, AA, C, D, 9v).

The Triton does do some figuring on it's own but also allows me manual control of charge levels. It has the thermal runaway sensor as well. Very handy when charging LiPo's.

[mfr02]

My TX charger for the last several years has been a "universal battery eliminator", one of those with a 4 way plug plus a small one, with various voltage switchings. I inserted a 20 ohm 4 watt resistor into one of the leads. It just plugs into the TX and gets left overnight. No problems, cost today about £3.50, from a poundstretcher type store and Maplin. I am sure there will be a US equivalent for both.

[Kmot]

I use the Triton also. It's an awesome charger. And it has seemingly unlimited capabilities.

Here I am charging 16 cells in parallel. I also can charge four 6-cell packs at a time using a series-parallel harness.

[MILLERTIME]

Powerex MH-C800S Eight Cell Smart Charger for AA/AAA Batteries-$59.40 Shipped.
http://www.lawmancollectibles.com/servlet/Cart?cart_id=6683367&sfs=659e49da
Cheaper than evellbay.

[Predreadnut]

Thanks for the info guys. My preference would be to simply plug a charger into my Tx and charge all 8 at a time,but I cant find a charger with the right end to fit my Tx. Its a Proboat Tx and even the tech guy at Horizon doesnt know what charger to recommend. Horizon sell's a Tx with a charge port in the side of it and they dont know where to get a charger for it?! I guess the next best thing to do is find a charger that will charge all 8 AA's at the same time. OK call me lazy, but I hate to take all those batteries out of that holder and spend 8+hours charging batteries. I also wonder why I have to recharge my batteries every time I go to the lake. It seems that a 2600mah battery would allow more than one two hour trip to the lake. Could the Tx be discharging the batteries in between sessions even though its turned off? I'll take a look at the links suggested in the mean time. Thanks

[Shaun Hendricks]

NiMh and NiCd batteries have a naturally 'high' internal resistance. That is a fancy way of saying, they lose their charge over time very quickly.

Most NiMh's will find 30% of their charge gone in a month. Your transmitter may be keeping some things active even in an off state (memory, timing clock, etc.) if it's a computerized transmitter.

Most battery connectors for TX's are either JR mini plugs (sometimes called mini-tamiya- they are usually red in color and 2 lead female) or classic "9v" style snap on. Your local Hobby Shop should have some of them in stock. You then just need to wire them to your standard 'charger'. I use my Triton to charge my TX batteries all the time.

If you are REALLY lazy, you can just make an external battery system for your TX. 8 cells is 12volts. Just take a normal 12v gell cell, run a 'coil' style instrument cable to it and put the JR connector on the other end. If you run your boat from a chair, sit down and run all day long then charge the battery on a simple trickle charger or plug into your cigarette lighter on the way to the pond. The lead acid battery would run your TX for a month of weekends before needing to be recharged!

[bbruce_llee]

Don't go to walmart to buy chargable batterys.,...
they suck!!! wasted like$40 on stupid rechargebles

[toesup]

Don't go to walmart to buy chargable batterys.,...
they suck!!! wasted like$40 on stupid rechargebles

chargable?... suck? (batteries that suck? uh?)... and Stupid?..

How can a battery Suck? :eek:
I've not come accross a 'Stupid' battery before.. NiMh, NiCd, LiPo yes, but not 'Stupid'..
Is this a new thing? :o

[mfr02]

Wherever they are bought, batteries with a recognisable "big name" will be OK. Cheap no-name specials are cheap for a reason.

[nick_75au]

Hi Predreadnut,
Most hobby stores will have a generic overnight charger for the TX (usually has a 4 cell RX lead as well).

Only thing to be careful of(see below) is the polarity of the charge port, most have tip(center) positive, JR have tip negative, all my transmitters have the same plug Sanwa Futaba Hitec and the oposite plug JR.

The Proboat you have should also have the same size port and it is standard tip positive (just checked the manual) its the 27meg two stick but all will be the same. Only problem I see is the charge port is optional?
http://www.proboatmodels.com/ProdInfo/Files/PRB8021-Manual-8-30-07-BPW.pdf

Regards
Nick