# Battery charging question



## Jerry Barnes (Jan 2, 2008)

I have a battery car(tank car) that has two 9.6 volt battery packs stuffed into it. Can I just charge the batteries in it by plugging one battery charger into the plug I hook to the locomotives with? Save digging them out. I guess I would turn the switch to 'on' to charge. I don't have one of those charging plug things on it, just one of those Aristo type plugs. Would appreciate any help.


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## Greg Elmassian (Jan 3, 2008)

Packs in parallel or series? 

What type of charger? 

The amp hours of the packs and the max charger current should be a consideration on the MU plug also. 

Regards, Greg


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## TonyWalsham (Jan 2, 2008)

As long as the two packs are in series and the packs are matched, it should be quite safe to do that as long as you ensure the polarity of the charger output is correct.


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## Jerry Barnes (Jan 2, 2008)

Thanks guys, they are in series, will save me some trouble.


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## Paul Burch (Jan 2, 2008)

Jerry,
Like Greg brought up.what kind of charger are you using? Is it rated for that voltage?


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## Jerry Barnes (Jan 2, 2008)

It's the charger that came with the Radio Shack batteries. Has a switch for Ni-cad or Ni-Mh. Just a plug in thing about the size of a plug in power supply.


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## K27_463 (Jan 2, 2008)

Based on that description, the chances are VERY high the charger will not work.It is quire rare to find wall wart chargers that can do 14-18 volts series setups. 
In addition, I know of no Radio shack wall wart item that will do that. When they sell you battery packs rated at 7.2v for example, a six cell stick pack, the charger provided is rated for 7,2 v packs, not 14.4 It is quite possible for you to charge both packs in series, in place , but you will need a smart charger rated for 12 or more cells. 
The other option is more complex, wire in 2 charge jacks with a toggle switch and associated wiring so each pack can be charged separately. This solution is more hassl ethan it is worth, far better to get a good charger, as it will have more other uses. 
jonathan/EMW


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## Torby (Jan 2, 2008)

With the 2 packs in series, you have a 19.2v battery and you'll need a charger for 19.2v batteries.


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## Richard Smith (Jan 2, 2008)

Jerry, 

Is your charger the little white colored plug in job that comes from Radio Shack? I' have four of them and have been charging my 14.4 volt packs with them for a number of years. It takes about 16 hours (overnight) to fully charge my NMHI packs and they shut off automatically. I believe they were only $10-20 originally.


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## Greg Elmassian (Jan 3, 2008)

And thus the reason for my very first question. 

Jerry, only the more expensive chargers automatically adjust to different voltages. 

Do you have a model number on the charger? I guess we could look it up for you, but the charger itself should tell. 

Regards, Greg


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## Jerry Barnes (Jan 2, 2008)

Okay, what is a decent charger for not a whole lot? I mostly have the 9.6 packs, some 7.2's. Has those Tamiya plugs on them. Mostly single charging, but being able to do a double(19.2 volts) would be handy. I'm looking at moving over more to the 'dark side' of trains and go almost all battery.


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## Michael Glavin (Jan 2, 2009)

Jerry, 

While you can purchase a GOOD NiCD/NiMH charger that will do as many as 14 cells for a $100.00, I wouldn’t advise same with the atypical battery packs available at Radio Shack and the like. Reasons being all cells are not created equal; the battery pack will only be as good as the least productive member or cell. Multiple cells will not discharge or charge equally; accordingly this behavior creates a conundrum with multiple cells in series. That said high quality battery packs comprised of matched or graded cells is another consideration. 

Ultimately regardless of the cell chemistry charging each cell independently is best! Smart chargers with the appropriate wringing harness and or cell charging/balancing taps are best suited for high count multiple cell batteries. There are many offerings in this regard but most batteries unless again they’re high end are not wired for this type of charging algorithm. 

In short you’re much better off charging the aforementioned batteries as single units. You’ll garner better results, longer life and fewer headaches in the long run. 

Pinacle charger link below, this is a GOOD charger…. 
http://www.horizonhobby.com/Products/Default.aspx?ProdID=EFLC2020 

Michael


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## Del Tapparo (Jan 4, 2008)

Posted By Michael Glavin on 24 Jul 2010 07:30 PM 
...

Pinacle charger link below, this is a GOOD charger…. 
http://www.horizonhobby.com/Products/Default.aspx?ProdID=EFLC2020 ...


That's the one I use, but I would advise some caution here. When you buy a versatile charger like this, you can charge the battery pack at any rate you want; i.e. .1C, 1C, 10C, whatever! You can easily fry your battery pack by charging at too high of a rate. This charger will set the proper voltage for you automatically, but you have to set the charging rate. In general, a nice safe charging rate for any NiCad/NiMh battery pack is 0.1C. That means if you have a 4000mah rated pack, 0.1C is 400 ma (0.4A). At this charging rate, it will take approximately 10 hours to charge a fully depleted battery. Faster rates may shorten the life of your pack. (I'm no expert on this. Just what I've picked up as a user.) The R/C car guys certainly don't follow these rules, but that's a whole different ball game.


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## TonyWalsham (Jan 2, 2008)

14 cell chargers are fairly easy to obtain. 
I use a Maha which works really well. 

Jerry wants to charge 16 cells. Chargers that can handle 16 cells are bit thin on the ground, let alone a low cost one that has "smarts". 
Can anyone suggest what might be suitable for his needs? 
If nothing is forthcoming, it may well be that charging each pack separately is the only solution. In which case a simple two wire connection will need to be augmented with some complicated switching in the loco.


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## Torby (Jan 2, 2008)

I was going to post a link to what I use, but the web site is being horrendously slow. 

http://www.all-battery.com/192v-24vmulti-currentsmartuniversalbatterypackcharger.aspx 

Does my 3800mAH (That bother's me: 3.8AH.) in about 2 hours. Senses full charge by watching for the temperature rise. On sale now for 10 bucks. I have 2.


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## Del Tapparo (Jan 4, 2008)

Posted By Torby on 26 Jul 2010 06:47 PM 
I was going to post a link to what I use, but the web site is being horrendously slow. 

http://www.all-battery.com/192v-24vmulti-currentsmartuniversalbatterypackcharger.aspx 

Does my 3800mAH (That bother's me: 3.8AH.) in about 2 hours. Senses full charge by watching for the temperature rise. On sale now for 10 bucks. I have 2. 
Wow. That is a great deal if you use battery packs in that voltage range. I use the Tenergy charger for Li-Ions and it works great. There prices for all the other voltage ranges and chemistries are still great: $20 - $25.


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## Jerry Barnes (Jan 2, 2008)

I did a little re-wiring, now it's pretty easy to pull the batteries out of the tank car that I made for the rotary. Plan to us it as a battery car for the Pacific, RS-3 and the FA's when I pull freight with them. Thanks for all your help. I'm moving closer to the 'dark' side.


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## pimanjc (Jan 2, 2008)

Jerry, if the batteries are NICAD, you can use a Craftsman 19.2v drill battery charger by adapting a couple of blade connectors and the matching plug. Also, multi-type/voltage/chemistry chargers can be found on ebay fairly cheaply. Do a search undre model aircraft lipo batteries and chargers [seller giftshop_com30]. 

JimC.


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## eheading (Jan 5, 2008)

Jerry, I definitely lean towards the "removable battery" plan for my railroad. This way, if batteries do go dead while I'm running, it's about a 60 second operation to exchange them with a fresh set of batteries and keep on running.

Ed


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## East Broad Top (Dec 29, 2007)

I'm also definitely in the "removable battery" camp, as often as possible. (Not all installations lend themselves to it.) I get 3 - 4 hours run time out of a 2600 mAh battery, and can charge it inside of 90 minutes. Not too shabby. The hardest part is remembering which tenders have the removable coal loads vs. the removable shells. 

Later, 

K


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## TonyWalsham (Jan 2, 2008)

You can always wire the charge port in the loco to operate either as a charge port on an access port to take extra auxiliary batteries carried in a trail car. 
That way you simply plug in the auxiliary batteries and run for as long as you want without having to remove them from the loco.


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## Torby (Jan 2, 2008)

I do the removable battery thing too. The little $10 charger sometimes didn't quite keep up with Madam Mallet, so I have 2 chargers and 3 batteries, the "Original" battery, the "Repaired" battery and the "Ugly" battery.

With NIMH batteries, be careful they don't run down while you're not paying attention and the train stops, drawing lots of current. This kills cells. Alas, I do it too often. I went to supper at the Botanic while my loco ran. I'd just changed the battery. I waited and waited and waited, they'd lost my order. Loco had been sitting for some time when I got back. oops. I once made a low voltage cutoff gadget, but it was too sensitive and often cut off while starting the loco. Should try again.


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## Greg Elmassian (Jan 3, 2008)

Actually the current goes down as the cell depletes. (As the voltage drops, less current will flow, Ohms law) It's the problem with polarity reversal when a cell gets to zero, and also just abuse of the electrolyte and the anode and cathode. 

Nicads are more famous for polarity reversal. 

Nickle-metals just get mad and don't work as well later. 

LiIons get even and catch on fire later to teach you a lesson. 

Regards, Greg


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## Michael Glavin (Jan 2, 2009)

Posted By Greg Elmassian on 27 Jul 2010 09:03 PM 
Actually the current goes down as the cell depletes. (As the voltage drops, less current will flow, Ohms law) It's the problem with polarity reversal when a cell gets to zero, and also just abuse of the electrolyte and the anode and cathode. 

Nicads are more famous for polarity reversal. 

Nickle-metals just get mad and don't work as well later. 

LiIons get even and catch on fire later to teach you a lesson. 

Regards, Greg 

Your just having some fun right? If I was take these comments literally I'd be pondering same...

Michael


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## Torby (Jan 2, 2008)

Nope! He's telling you the truth.

Most Lithium packs these days come with a little circuit to prevent over discharge and the resulting unpleasantness. Just be sure if you buy LI that you get a charger made for them. I have NIMH just because there was a great AH/Dollar special at the time and I have a big tender to stuff them into so I didn't need the higher power density of LI.


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## Trains (Jan 2, 2008)

Jerry, I'll be waiting for you on the dark side!


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## Greg Elmassian (Jan 3, 2008)

I took some fun in that I gave the cells "personality" 

But nicads often will reverse polarity if they are discharged to zero, and then when you try to re-charge them, now they are a dead short and really heat up, like hot enough to burn you. 

Nickle metal Hydrides can do the same, but don't seem to reverse polarity as often. But when you abuse them this way, their capacity is seriously reduced. 

Taking a li-ion to zero and/or overcharging can result in a fire, and that's documented. They can reverse polarity like nicads, and the results of charging a reversed polarity cell is normally fire. 

Yep, all true Michael. 

Regards, Greg


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