Hobby Chargers

Hi Caedom... I think there's a restriction on uploading images and attachments if you're a first time poster... In other words, there's a big blank space where the charger is supposed to be so I can't comment on what you posted.

But for the sake of conversation, a year ago the 80watt skyrc imax b6ac v2 was the way to go when working with individual modules. They were on ebay for $40 and we ended up with five of them, then last fall they became rare and price went way up.

So recently I bought a t240 duo by htrc which is better due to having a cooling fan and 75watt on two separate channels. It also has a DC power input option so you could potentially rig up wiring to power the charger by way of discharging a pack, or solar panels, power wall etc. They also cost under $80 which brings price per channel back down to the $40 range again.

Last night was using all these chargers and the HTRC sensitivity is too extreme and kept dropping back to 0amps even though the module wasn't done charging yet. Maybe I can address that in the settings? I like the HTRC graphing out how the charge is going, but maybe that's just a gimic. Too soon to tell?

 

I can see the link and image.
X4 AC Pro AC/DC 4 Port Multicharger

 

That is the updated version of the HiTec 44167 model. The main difference is this model has 10 watts per channel heat dissipation for the discharge cycle. (the 44167 had 5 watts)

It came out a year or two ago, but I thought they had stopped making them already. Maybe I was wrong about that.

Your most limiting factor for cycling modules is the discharge ability of the unit.

 

There's very few hobby chargers that discharge at a rate higher than 10w... But there is one that discharges at 25w here: HTRC HT206 AC/DC DUO 200W*2 20A*2 Dual Port 4.3" Color LCD Touch Screen Charger 736364519833 | eBay

But myself and my local hybrid nerds believe that relying on a heat dissipation resistor that's soldered directly to the circuit board can make minor heating issues more severe in some cases. What I prefer doing is use cheap 20w and 50w bulbs for 12v... Then once the bulk of the energy in the battery is discharge I'll use the the 10w resistors briefly via the discharge then charge function.

Another thing that's interesting with bulb discharge, which @Britprius pointed out is the resistance of the filament in the bulb changes depending on the temperature. So when a module is at full charge and the bulb is super hot the resistance / rate of discharge is high. But when you get down to then end of the discharge and the filament doesn't even light up, the resistance is very low.

This came in handy one time when I was lightbulb discharging five modules and forgot about them because it was late at night. The next morning when I realize "it finally happened" and voltage of all 5 modules was at zero, I unplugged them and voltage bounced back up without issue and those modules have been running normally ever since. I suspect if I had been using a true solid state resistor for discharge I wouldn't of been so lucky.

 

Lol, it was my adblock extension on my Chrome browser.... Of course google recently announce they're going to disable all ad block ability to everyone but their enterprise clients. Another part of the good old days of the internet is soon going away.

 

Here's a pic of my current rig of 5 discharge and 5 charge... Am about to build a brand new rig of 6 charge and 6 discharge with higher quality multi-meters that measure down to the thousandth of a volt. I think I'll be using (3) HTRC 240T duo primarily because it has both AC, as well as DC inputs in the 11v-18v range which would allow me a third and much less wasteful option for pack discharging once I build wiring harnesses.

 

You have this kinda twisted and backwards. The inverse nature of Ohm's law can be confusing.

The resistance of a light bulb goes up as it gets hot. This causes the bulb to draw less current. So at a higher voltage the bulb gets hotter, resistance goes up and current down. This is what keeps the bulbs from quickly burning out.

As the voltage drops the resistance of a bulb drops also. This causes the bulb to draw more current.

All this works out to the opposite of an ideal module discharger which would draw high amps at high voltage and less amps as the voltage drops.

Resistors have fairly flat but not perfect resistance values regardless of temperature.

 

Thanks for clarifying, and yes light bulb discharging is not ideal, but can be useful for load testing, as well as quickly draining a fully charged module down to a level where a 10W resitor inside a charger can make quick work of the rest of the discharge cycle.

But at the same time I'm sure you'll agree, as @Britprius once explained to me: a very slow 250ma discharge of a module for reconditioning is best and that speeding up that process doesn't help anything other than getting the work done faster, perhaps more sloppy due to the haste?

Another crucial aspect to all of this is the quality of your equipment. Using hobby chargers to rebuild HV battery packs is a viable way to go, but my buddy Joe in Bend, OR who has $30K in equipment built specifically to rebuild battery packs will always be miles of head of any home DIY effort when it comes to quality of work as well as how many modules he can process simultaneously.. I think he can do as many as 80 channels/odules at once with one if his configurations. See pics below for what will always be better than a hobby charger:

 

Thank for asking... Inconsistent is the nature of DIY. Basically it's a debate about what type of cardboard builds the best house... You gotta spend many thousands of dollars if your truly want professional laboratory quality charging & discharging gear. AKA: want to live in a real house.

 

I wonder if you meant 12V bulb. Would 12V bulb work with the 7.2V battery module? I thought the voltage of the bulb has to be similar to the voltage of the battery..

 

Wattage (W) and voltage Rating (V) define Resistance of the filament in an incandescent bulb. Here you are just using the bulb as a low cost load on battery. So it is OK to use 12 V bulb on a module with lesser voltage. It would draw less current (I) and would not glow as bright as it would on 12 V, but it would still safely discharge the battery. A lower voltage bulb connected to a higher voltage source on the otherhand would draw too much current and likely would fuse. W = V * I

 

I see. Thanks for elaborating on this. Earlier I thought a lower voltage battery won't be able to light up the higher voltage bulb.

Another question, how long does it take to complete the discharge process, using this method? I assume we calculate this by multiplying the voltage of the battery (7.2V) and the capacity of the battery (6.5Ah), and then divided by the watts rating of the bulb (80W), which equals about 35 minutes. Is this calculation method correct?

(PS: I used the 80W bulb example since this is the highest watts of 12V bulbs I can find on Amazon, and I assume this could speed up the discharge process.)

 

I use the hobby charger PriusCamper first referred to, and it has its share of quirks. It's solid for manual charging but I cannot get it to run pre-programmed or multiple cycles. I don't know if my unit has a problem since it will work minimally for my needs.

It also has optional software that is not very stable. Once initiated, it is easily disrupted by any number of changes in your computer(screen savers, closed lid, accidentally pressing any button on the Charger). I'd say the software an alpha-version with no debugging. You can't turn your back on it.

 

They work just fine. I use a 20W and a 50W 12V lamp. If I need higher discharge I link them with clips.

 

Does anyone have experience of the Skyrc T100 SK100102? For my gen 2 2005 with 108k with P0A80 and P3000 codes. Torque pro shows block 10 is bad. Here in Bristol UK we are heading in to another lockdown so its a good time to try and sort it.

Thanks. I tried to post the spec sheet but as I'm new it won't let me. Brilliant forum by the way!

Thank you, Mike

 

Here is the spec-

Power
Input Voltage: AC 100-240V
Charge Wattage: 50Wx2

Battery
Battery Types/Cells:
LiPo/LiFe/LiIon/LiHV: 2-4 cells
NiMH/NiCd: 6-8 cells
Pb:6/12V
Battery Capacity Range:
LiPo/LiIon/LiFe/LiHV:100-50000mAh
NiMH/NiCd:100-50000mAh
Pb: 100-50000mAh

Charge and Discharge
Charge Voltage
LiPo: 4.18-4.25V/cell
LiFe: 3.58-3.7V/cell
LiIon: 4.08-4.2V/cell
LiHV: 4.25-4.35V/cellNiMH/NiCd: Delta peak detection: 3-15mV/cell ; Default: 4mV/cell

Discharge Cut-off Voltage
LiPo:3.0-3.3V/cell
LiFe:2.6-2.9V/cellLiIon: 2.9-3.2V/cell
LiHV: 3.1-3.4V/cellNiMH/NiCd:0.1-1.1V/cell

Charge Current: 0.1A-5.0A
Balance Cells: 2-4 cells
Balance Current: 300mA/cell
Safety Timer: 1-720minutes & OFF
Charge Method:CC/CV for Lithium batteries.
Delta-peak Sensitivity for NiMH/NiCd batteries.
CC/CV and float charge for PB batteries

 

Are you thinking of buying this? Or do you already own it?

If you're still comparison shopping I upgraded my 50W skyrc chargers with the newest version which is 60w and has a much faster processor: iMAX B6 V2 Changer The amount of time it takes to charge a module is way faster with the new version and also much less issue with overcharging related heat compared to the old ones.

 

Thanks for your reply. I'm still shopping around and pretty bewildered to be honest.

How long did your 50w skyrc chargers last and was the heat buildup a problem?

How much faster would you say the new ones are?

Is it a decent brand overall?

I've not done this before and don't know if it will work so I don't want to invest too much in the kit if I can help it. It seems the cheap clones are best avoided but would you say the skyrc T100 would be better? They look tempting as they do 2 modules at a time and work out at £23 per module and have AC power supply.