Large Scale Central

Smart Charger for Li-Ion Battery packs

Electronics Power and Sound
#1

I am in the process of making some battery packs for a couple of my locomotives. These will be 14.4 volts, using (4) 3000ma Li-Ion 3.7v cells. I have already purchased the batteries and the protection monitor/charge pcb to go with them. I am starting off building two battery packs and might make more in the future. Can anyone recommend a good, inexpensive smart charger that I can use to charge these packs once I have them built. Is it possible to use the crest / aristocraft one that is used to charge thier 24v amp battery packs?

Dan S.

#2

I would do some serious homework on th net when it comes to charging systems for Li_ion batteries. Everywhere they talk about charging etc, there tons of warnings. Especially about overcharging. The 24v charger is designed for those 24v batteries. Just be careful please.

#3

Most cheep charger are for a single voltage batteries. If you are
making the investment on batteries, I would get this charger
http://www.all-battery.com/SuperComboTenergyTB6BalancingChargerSwitchPowerSupply-90203.aspx
I will charge almost anything.

Rodney

#4

I looked at that one before I purchased the batteries and the charge/discharge controller pcb to make the packs, but since I am never going to make packs more than 14.4v, I just need one that can only charge a 14.4v pack. I have read a bunch of stuff about the Tenergy packs and most people think they are OK. And some think Li-Ion batteries of any kind are a bad idea and dangerous. They seem to have some sway in the government at well with all the new regs on Lithium batteries. I came across one website the other day that was selling the Li-ion battery cells for 4.95 at 2600mah. but they only would ship them via UPS and charged a $35.00 hazardous cargo fee in addition to thier $15.00 shipping charges. I’m sorry but I don’t know anyone in thier right mind that would pay $50.00 to purchase a $5.00 battery.

Thats one of the reasons I don’t buy electronic parts from Sunrom out of inda as they only ship DHL and charge $40 to $60 for shipping for a $2.00 part.

In any case in help in findind good 14.4v Li-ion smart charger would be greatly appericated.

Dan S.

#5

Tenergy Li-ion 3.6V-14.4V Battery Pack Universal Smart Charger

#6

This is the one that I have been considering purchasing to charge the packs I am building. http://www.all-battery.com/universalsmartchargerforli-ionpolymerbatterypack37v-148v1-4cells.aspx

TLP-2000 Tenergy Universal Smart Charger for Li-Ion/Polymer battery Pack (3.7V-14.8V 1-4 cells)

Any Thoughts?

Dan S.

#7

Thanks for the info Mike: Hows the weather there? I used to live there and went to Edison High back in the 70’s Was in the 90’s here today and it isn’t even close to summer yet. I think it’s going to be a long hot one when it gets here. I almost want to build the railroad indoors, but have no room. good thing for the shade tree.

Dan S.

#8

Been really nice for the beach. Sunny and probably about 75 today. Supposed to get warmer as the weekend approaches. My brother’s RR is up in Lake Arrowhead. So that RR gets a little snow and mostly fair weather. Not at all like Big Bear.

#9
Dan Stuettgen said:
This is the one that I have been considering purchasing to charge the packs I am building. http://www.all-battery.com/universalsmartchargerforli-ionpolymerbatterypack37v-148v1-4cells.aspx

TLP-2000 Tenergy Universal Smart Charger for Li-Ion/Polymer battery Pack (3.7V-14.8V 1-4 cells)


That’s one of two I use. Some of my locos, and my lighted cabooses and passenger cars run on 7.4 volt packs, and I’m working on a loco now that will use an 11.1 volt pack. It’s nice to have the flexibility with this charger for those packs in addition to my normal 14.8 volt packs. It charges a 2600 mAh pack in around 3 - 4 hours or so.

Later,

K

#10
Dan Stuettgen said:
This is the one that I have been considering purchasing to charge the packs I am building. http://www.all-battery.com/universalsmartchargerforli-ionpolymerbatterypack37v-148v1-4cells.aspx

TLP-2000 Tenergy Universal Smart Charger for Li-Ion/Polymer battery Pack (3.7V-14.8V 1-4 cells)

Any Thoughts?

Dan S.


That’s the one that I have. Very basic, but it works. Does not do any balancing which can be an issue i the cells aren’t a very close match.

#11

Thanks for the input guys, I think that I will get the charger that I mentioned in the previous post as everyone seems to think it is a good selection for my needs. I let you guys know how it works out once I get the packs built. got the UPS notice today that my batteries will be delivered on May 3rd. And guess what, didn’t have to pay a HazMat fee along with the shipping charges and that was for (8) 3.7v 3300mah Li-ion Batteries.

Dan S.

#12

Dan,
This is the one I have for 14.8v Li-Ion batteries. A fast smart charger. 1500ma versus 500ma on the one you chose.
Not much difference in price. But no adjustable voltage.
Ralph

http://www.all-battery.com/universalfastsmarttlp3000chargerforli-ionli-polymerbatterypack148v4cells.aspx

#13

Ralph: I will keep that one in mind when I go to buy the second charger. I lke the other one for its different voltage capability, since I might make some different packs in the future for lighting.

The packs I am building will be 3 amp packs as the cells I purchased are the 18650 3.7v 3000 mAh AA cells. Not sure how long it will take to charge them , but since I am building 4 packs, two will alway be on charge while the other two are being used. Based on my experience with the 2amp packs that I am using with the Crest/Aristocraft Train engineer in which I get a bit over 4 hours of run time. I think my 3amp packs should get me to about 5 or 6 hours or run time with my Bachmann or Delton locomotives pulling 5 cars.

Dan S.

#14

Got my Li-Ion Cells today along with the charger. I have to admit that I did not expect to get them this fast. I only ordered the Charger two days ago and the Battery cells 3 days ago. In fact I placed two orders for the Cells. The first one was for 8 cells to make two packs and then thinking about it that with as cheap as I got them I should order 8 more so I could make (4) 14.4v Battery packs. I bought the TLP-2000 Tenergy Universal Smart Charger for Li-Ion/Polymer battery Pack (3.7V-14.8V 1-4 cells) and It is very good quality and can’t wait to put it to use. I just waiting on the Battery holders and the PCB’s and then I can assemble them and start charging them.

In case anyone else is making your own Batery packs, You can get the Holders in various number of cells from Digikey
the part number is BK-18650-PC8-ND for the 4 cell version.

Dan S.

#15

Hi Dan.

I was looking for the current capability specs of the spring contacts in the holders.
I could not find any specs.
Typically the AA size cells holders are not designed for much more than 1 amp continuous. Any higher and the lack of spring pressure causes them to over heat creating a resistance that reduces power capabilities even further.
Perhaps these are more capable. I would like to know what the limits are if possible.

#16

Tony: the cells I got are actually larger than AA cells. They are about 1/2 again the size of a AA battery but not as large as a C cell. I was unaware that the Lithium cells were larger so I purchased a couple 4 AA battery holders from my local electronics store. Well I found out pretty quick that I could not use them, so I just tossed them in my electronics parts stash box for some future use. Since the holders I had didn’t fit the batteries, I did a Google search and found that digikey had them along with a few other suppliers, but they wanted more for them and some had them prewired in parrellel for greater amperage output , but not for voltage. If you go to the digikey website they have the specs on the holder. I am assuming that they sould not have any issues with them as they are specifically designed for Lithium Ion Batterys.

The specs I read say that the contacts are made of 302 Stainless Steel Spring Temper, Nickel plated. Here is the link to teh specs. http://www.batteryholders.com/BK-18650-PC8.PDF .

To find out what the resistance the contacts are I guess that would be a question for the manufacturer which s Memory Protection Devices, Inc. Farmingdale, N.Y. http://www.memoryprotectiondevices.com/ They sell the holders under thier subsidurary company of http://www.batteryholders.com/show-part.php?part=BK-18650-PC8.

I found this in some of thier technical specs on the Batteryholders.com website under contacts.

Lithium Battery Holders

Features:

Easy battery changes without any tools or soldering
Light weight with high strength
30 years of worldwide sales in many diverse applications with documented performance
Exceeds requirements of ANSI/EIA-540J0000
Contacts:

Bright nickel plating over stainless steel base metal
Excellent in backup applications or low current applications
Industry standard pc pin spacing
Outstanding resistance to corrosion
Low resistance, under 50 m¥Ø
Plastic:

PBT*, excellent chemical and solvent resistance
Broad service temperature range with excellent thermal cycling performance
Excellent toughness and strength
Dielectric strength 560 volts/mil at 25¡Æc for 5 sec.
Insulator resistance: 5000 M§Ù minimum

I hope this answer your questions.

In any case I have them on order. Got the charge / Discharge monitor boards today, so just waiting on the holders now.

Dan S.
Denver & Rio Grande Southern

#17

Dan.
The operative sentence above is Excellent in backup applications or low current applications

Back up usually means just that. i.e. Not for primary use where there could be a higher current consumption.
They could be OK but, as in cell pack construction with other chemistries, it would be much more reliable if the cells were soldered together.

Please keep us informed as to the long term reliability.

#18

Dan,

Take a good look at the holders polarity configuration before you start wiring the 18650 cells in series. PCB boards have to be wired between polarity contacts and it doesn’t look like this holder offers that; meaning: (+ -/+ +/- -/+ -) that you have five wire leads to a 14.8V lithium battery-pack, three of which are soldered or welded to nickel tabs between cells 1-2 / 2-3 / 3-4. When you receive your PCB board you should have cad drawing of the terminals outputs and which terminals they go to. If this is your first time wiring a lithium battery to PCB board, be very careful. Make sure you wire the PCB from negative to positive, and P- & P+ are battery output leads to your engine.

Warning! If you make a mistake wiring the wrong leads to the wrong PCB output, you will short circuit the PCB board and may cause the cells to get warm and catch on fire.

Lithium cells are defined and named after their size. An 18650 cell is 18mm in diameter by 65mm in length.

Rick Isard
Cordless Renovations, LLC

#19

Guys,
Here’s a site that will help with lithium based cells. It shows how to wire packs in series and parallel with balancing wiring.
http://scriptasylum.com/rc_speed/lipo.html

You really should balance wire the packs & use a balancing charger. There are many to choose from. They are not too pricey and they charge packs safely.

As I’ve said before regarding lithium technology, take a look at the Batteries & Chargers forum on RCGroups.com, its a wealth of info about lithium technology which is used extensively and safely in RC applications.
Dave

#20

Thanks guys for the information.

I do have a couple of questions. First, How do you tell if a Cell is protected. The ones I have don’t say they are protected nor did the site I purchased them from list them as protected, however I sent them an email asking if they were and they said that they were protected.

Which brings me to question 2. Can protected cells be wired in series or did I waste $40.00 of (16) 3.7v 3000mAh batteries.

Rick: I received the charge/ dis-charge PCB the other day and did not receive a drawing on how it is to be wired, but I have downloaded it from thier website. It has 5 solder pads for the battery to be wired to and 2 pads for wires to go to the motor / charger. It look self explanetory. So based on the PCB, I would run the wires from the contact on each of the cell holder positions to the PCB and that would take care of the series wiring. The one I have is from Batteryspace.com, It is the PCB withe Fuel gauge for 14.8V Battery pack (5amp +/- 1amp) PCM-CS004S-06