What is a good charger?

[Batfish]

My current favorite charger in terms of features and versatility is the eStation 902. I do not own one of these chargers, nor have I used one, but the features and versatility of the charger seem to be well above and beyond most others I've seen. The charger has some good user feedback on some aircraft forums, too.

http://www.bantamtek.com/products/charger-902.htm

Up to 32 cells of nimh in series and up to 12S lipo is nice, plus many other features including a temp sensor and USB port with a PC program for viewing the charge information.
The retail is around $300, but if it lives up to it's potential it may be one of those "only charger you'll ever need" types of chargers. Sometimes it's worth looking at something that's a little more expensive. It's always up to the person making the purchase to determine if this is one of those times.

I still use my Duratrax ICE charger, and I love it.

[jhautz]

Another option may be the new MRC Superbrain 989.
http://www2.towerhobbies.com/cgi-bin...&I=LXLTW4&P=ML
http://www.modelrectifier.com/search...ew.asp?ID=6863
Looks pretty slick for $169.
Can do 8s at 10A and all of the other types of batts and it s Ac/Dc so you can use it in the pits and at home easily. Included temp sensor and can power a com lathe and other 12v pit tools. I'm probably gonna get it when it is out in a couple weeks.

Seems like a bargain for all it does.

[MetalMan]

It may be able to do AC, but that's not any good if it only includes a 10amp power supply! With only a 4s Lipo battery the max charge rate is about 6.5amps with the stock power supply.

Just to put this out there, I have a 3.3v/5v/12v power supply that can handle 30amps at 12v without dropping it's voltage. It's from a computer server, but works without a load on the 5v line. I use another one of these (they come in pairs) for my charging duties, and it has yet to let me down! The price is insanely low (never been used). PM me if you're interested.

Well, I finally got around to finishing up the buggy. I bult the 2 packs each in identical 5s1p configuration. They are set up like this: 111= so theres 3 cells wired sxs then 2 more wired sxs perpendicular to the other 3. This allowed for best weight dispersment and the lowest cg possible.

I mounted the motor so the shaft is directly above the center diff spur and the back of the motor is near the back of the buggy . With my buggy having 2 chassis plates this made mounting everything extremely easy.

I'm charging the packs right now 1 at a time at 3 amps each not using the balancer as I havn't put taps on the packs yet.

I'll take some pics now of the buggy and packs and post them here, and hopefully some bashing vids later today.

MRC 969 Pro is what I use, and I also use a computer power supply that puts out 16 amps on the 12v line and when the charger is plugged into DC power you have all the amps available of that battery. It has plenty of adjustments for lipo's plus it will charge 2 packs at a time upto 8 cells on each channel.

[BrianG]

I too have been looking for a charger. My requirements are:
- Able to charge up to 10s Li-XX
- Able to charge up to 10A (at max voltage)
- Able to adjust the cell voltage. This would be really handy if those A123 systems M1 cells become popular with their 3.6v max charge, or any future batteries that may have odd max voltages.
- Able to charge Ni-XX 20+ cells.
- Adjustable current in .1A increments.
- 11-15v DC power supply input. For a while I didn't like this idea, but now I think about it, it's a good idea. Since the 11-15v input is lower than the possible charging output, it must have a switching power supply internally. This is nice since the supply can adjust its output based on the voltage and current required without much loss. If a linear (regular AC transformer, filter, regulator) circuit was used, it would be large, heavy, and inefficient. The output voltage of this type of power supply would have to be about 50v @10A. Charging a relatively low count of cells (say 6-7 NiMH) at a higher current would heat the unit up a lot due to the difference between input and output voltage * charge current. In short, quite smart. (Sorry for the rambling).
- I guess able to charge Pb cells would be nice even though I never plan to use it.

Unfortunately, I can't find a charger that will do all of this. If I'm gonna spend $300+ on a charger/balancer, I'd like to get one that was fairly resistant to obsolescence.

A little off topic, but why don't Li chargers have built-in balancers (besides the reason for manufacturers to make more money off a seperate product)? That way, the balancer would be matched for the capabilities of the charger and be able to be in a closed loop with the charger much like the TP1010 unit.

One more slightly off-topic item: With so many Li chargers out there, why not one that is essentially multiple 1s chargers in one package? This would negate the need for a balancer and would remove the possibility of calculating the wrong total charge voltage from manual entry or "smart" mode. And don't tell me because of cost, those charger IC's are quite cheap in quantity.

Phew. Long post. :013:

[MetalMan]

Brian, one of the biggest reasons why there aren't more parallel chargers (that charge through the taps) out there is because the taps can't handle it. Standard Polyquest-type taps heat up at only 3amps because of their high resistance. But, FMA has brought a solution to your question, in the form of the Scorpion and BalancePro systems. However, the BalancePro charge can only do 6s at 10amps. With this setup you would also need the BalancePro taps.

There is no single charger out there that can do what you want. Probably the closest is the Schulze isl-8 936, as it can do up to 310watts (7s Lipo at 10amps). There is an update that can be obtained from a certain company that adds a charge profile for LiFePO4 (Lithium Phosphate, known as Saphion) cells which have a CV voltage of 3.65v. This charger does cost ~$900, though.
Then there are the Orbit Microlader chargers. These have an updated profile setting for the same CV voltage as the Schulze, but the maximum charge power is only 275W.
Then there's the TP-1010C, which can do 10s at 5amps or 5s at 10amps. It does have a storage setting of 3.8v that could be used for A123 cells and should still be safe.
One last charger:
http://www.tmenet.com/pdf/Xtrema%20Spec%20Sheet.pdf
10s at 8amps. It can be set to charge down to 3.7v. This may be your best bet. Only downside (which isn't so bad) is that it costs $240.

So, take your pick :).

[squeeforever]

I'm actually on the list for a discounted price on the Extrema. It was supposed to come out MONTHS ago....Don't wait on it. That much I know. It's like the CC Mamba Maxx :p. Anywho, there is a charger that can do alot of what you want....The E-Station 902. It can charge 1-12S LiPo @ 9.9 amps and discharge at the same amperage, 1-32 NiMH, USB port to be hooked up to computer, temp. sensor, and 2 outputs (very convienient IMO). I just got my E-Station 701 today and its GREAT! I love it! Best charger for the price. Its usually $189 but I got it for $150. The 902 is $299 and well worth it. Plus, the 701 (and 902 I think) have a port to hook up a special type of tap so it can monitor the voltage of the pack. Only thing is, it won't balance them through it :frown:. The temp sensor is also a very nice feature. One more thing it can do...it can be adjusted for the type of Lithium cells. 3.6 or 3.7 volt cells.

[BrianG]

Hmm. Oh well. I guess the only way to get exactly what I want would be to build my own, which really isn't all that hard except for the switching power supply on the input.

Metalman, you said that taps start heating up at ~3A. I thought that when you charged Lipos with a balancer attached that it, that you didn't hook up the main primary wires and simply charge/balance through the taps via the balancer (like in my attachment). So, if this is true (please correct me if I am wrong), then the most you can charge this way is 3A?

I still think it would be a good idea to slightly increase the size of the taps and charge each cell individually at ~5A through the taps. No need for a balancer that way.

[squeeforever]

Brian, why not the E-Station 902?

Well heres my battery and charger (without balancer) setup, could someone help show me how to put taps on to balance the packs. They are being charged as 2 seperate 5s1p lipo packs.

[BrianG]

Originally Posted by squeeforever

Brian, why not the E-Station 902?

You know, I must have been posting while you posted or something because I didn't even see yours until just now. Anyway, I just looked at the 902 and it does seem to have many of the features I was looking for. Kinda weird that the 902 will charge 12s, but the optional balancer only goes to 5s. Can these be daisy-chained for more cells? The manual says it can show the V of all 12 cells...

If I had to give up something in a charger, I could settle for a Li-only charger, 6s @ ~8A, but an adjustable nominal cell voltage. The 902 only selects 3.6 or 3.7v. I'm just trying to find something that will charge all Li, including future technologies. If I can't find all the features I would like, I'll probably get the Multiplex from Mike along with a 5s balancer (he only has a 4s). Or maybe the e-station BC5 might work then - that one has a built-in balancer.

Back to my previous post; if you look at the attachment, is that how a balancer is hooked up to balance while charging? And, am I right that you can only go up to about 3A charge current before the taps start heating up?

Thanks for the suggestions!

Side note: from what I've read, it looks like LiPo charging works this way. It will charge at a constant user-selected current (current is constant, voltage changes) until the charging voltage reaches a threshold value (4.1v?). At this point, it switches to constant voltage mode (voltage is constant, current changes) until the charging current goes to 0, which indicates a full charge. If that's all there is to it, why not a simple combination circuit that will charge at a constant voltage with a current limit? Wouldn't that essentially be the same thing?

[MetalMan]

Brian, the taps will heat up at 3amps. Look at this:
http://www.aircraft-world.com/shopexd.asp?id=3613
Those extra wires are to be connected through the main power wires on the battery. These wires carry the charge current, and the battery is balanced through the normal tap leads. I did a similar thing with my Great Planes Equinox (Hyperion LBA6 clone) except that those extra wires were soldered onto the circuit board inside the balancer. Look at this:
http://www.rcgroups.com/forums/showp...&postcount=141

The way that CC/CV works depends a little on the charger. On the ICE, CV doesn't start (current dropping) until the cells are at 4.20v. On the Multiplex LN-5014, the current starts dropping well before the voltage per cell is at 4.20v, but once it does get to that voltage, it remains constant. The Astroflight 109 doesn't use CV (but does use CC), and instead uses a pulse-charge method to finish off the battery (I'm a little unclear on what exactly it does, though).
You could make a circuit using two adjustable voltage/current regulators along with some resistors. I did this a while ago, but quit due to the strange inaccuracy and the fact that I didn't have a switching inverter (to increase the input voltage).
http://www.rcgroups.com/forums/showt...ht=DIY+charger

[Tazz]

Brian, I have the TP1010 charger and a TP balancer. The battery connects to the charger through the main power wires. The taps connect to the balancer and the balancer connects to the charger with what TP calls a data cable.

[BrianG]

OK, I was looking at the datasheets for the Hyperion EOS LBA6 and it does hook up like my picture above. And I can see where/how those extra wires work for the hi-amp version of the taps. Although technically, you could solder the extra heavy wires on the LBA6 and attached a Deans connector on it and hook it to the main battery wires, but using one connector for the battery charging would be easier.

Yeah, the TP 1010 with balancer is a nice unit, but really quite expensive. The Hyperion setup seems almost as good and is a little more than half the price of the TP setup.

For the money, the HP-EOS LBA6, HP-EOS 7i, and 6A harness seems like the best option for me. Aside from the higher vharge voltage and current, and the balancer that "talks" to the charger, what seperates the TP1010 from the EOS 7i?

Thanks for clearing this up for me. I'd hate to buy something jsut to find out later that it's not what I need/want. It's always cheaper to buy the right thing the first time than to buy twice!