Charger advice - ISDT D2 200w (12 amp model)

[azibux1]

Been away from here for a while - gone from an FTX Outlaw, to an FTX Carnage, to a Traxxas Slash and now to a Traxxas X Maxx in less than a year 😄 This hobby is addictive! 😄 haha

 

Question regarding my charger...

 

It's an ISDT D2 200w 12 amp model, less than a year old

Used to have 2S, 5000-6000 mAh batteries and it was fine, I didn't pay too much attention to the amps it was delivering but I'm fairly sure it was delivering what I asked for (1C).

Now I have my X-Maxx 8s, I got some 9000 Zeee 3S batteries.

I noticed channel 2 on the charger is consistently delivering 9 amps, but channel 1 is maxing out around 7.3 amps.

I swapped balance leads, XT60 extensions and Deans adapters - the situation remains the same, channel 2 delivering 9 amps and channel 1 maxing out at 7.3 amps - so it isn't any dodgy adapter or soldering, etc. - seems to be an issue with the charger itself. Both channels should be able to deliver 12 amps.

Is this anything to be concerned about? Or just a rubbish charger?

Less amps is better than more I guess at least 😃

[Ross9999992]

200 / 12.6 = 15.87 

You’re pulling 16.3 amps so the charger is over performing/being pushed to it’s limit.

 

I will do 12a per channel yes (just about) on 2s only.

 

Half decent charger - working harder than spec say it can 👍🏻

[azibux1]

Thanks Ross! 

 

What would you recommend I set it to for two 9000mAh batteries? Just to be a bit more comfortable on the charger. Sorry I'm struggling at the moment to work it out using the equation but any help would be appreciated! I see the maths you did but don't understand what the 12.6 (volts? But how did you get that figure?) is referring to and if it differs between 2S, 3S, 4S, etc. 😄

 

Or side note! Is there a charger you recommend that could charge 4 x 9000mAh (4S, I'm getting 4S soon) at 1C?

 

 

Edited October 22, 2021 by azibux1

[Kpowell911]

12.6v is a fully charged 3S lipo.

 

Charging 4x 9000mah 4s  lipos at 1C isnt going to be cheaap, would you consider multiple chargers?

Edited October 22, 2021 by Kpowell911

[lorrylemming]

You're looking at 160w per channel to charge at 1C. This would manage it. 

 

https://www.modelsport.co.uk/product/417456?gclid=CjwKCAjwwsmLBhACEiwANq-tXMisdpN6p5mTjC8mZYhEFMrchvFmN9eKtTIQ_l9mQrh0CojXv-eaOxoCvVEQAvD_BwE

 

But it might be more useful to yourself to buy two separate chargers.

[azibux1]

1 hour ago, Kpowell911 said:

12.6v is a fully charged 3S lipo.

 

Charging 4x 9000mah 4s  lipos at 1C isnt going to be cheaap, would you consider multiple chargers?

Cheers! I just didn't process that at that time of the morning haha - makes sense! 

 

Reckon I'll just charge below 1C / two batteries at a time for now. Doesn't take too long 

59 minutes ago, lorrylemming said:

You're looking at 160w per channel to charge at 1C. This would manage it. 

 

https://www.modelsport.co.uk/product/417456?gclid=CjwKCAjwwsmLBhACEiwANq-tXMisdpN6p5mTjC8mZYhEFMrchvFmN9eKtTIQ_l9mQrh0CojXv-eaOxoCvVEQAvD_BwE

 

But it might be more useful to yourself to buy two separate chargers.

Thanks! Yeah might just stick at charging below 1C and doing two at a time... 😂 

[Ross9999992]

3 hours ago, azibux1 said:

 

Thanks Ross! 

 

What would you recommend I set it to for two 9000mAh batteries?

 

Ahh no worries 👍🏻 I’d probably go with something like 7.5a per channel so as to not be pushing it to the absolute max (with the 15.87 ish available). That’s like .83c so about 72 minutes each/total for both.

 

With 4s you’ve got a hair under 12a available (200 watts / 16.8 volts = 11.9 amps) so if you were to get sub 5800 4s packs you could go 1c or higher mah and slower.
 

Personally (though some soldering required) I’d be looking at getting at least one ISDT q8 and a parallel charge board with your choice of connector along with an external psu (my choice would be a server psu…yes a computer server psu - a single one requires no internal mods for use). Parallel charging is great as long as you are careful…it’s also a lot safer on packs that are used at the same time (such as ran in series in an xmaxx) though I’d probably stick 3/4 on the q8 and do the other one on the d2 myself (assuming you get higher mah packs).

[azibux1]

3 hours ago, Ross9999992 said:

Ahh no worries 👍🏻 I’d probably go with something like 7.5a per channel so as to not be pushing it to the absolute max (with the 15.87 ish available). That’s like .83c so about 72 minutes each/total for both.

 

With 4s you’ve got a hair under 12a available (200 watts / 16.8 volts = 11.9 amps) so if you were to get sub 5800 4s packs you could go 1c or higher mah and slower.
 

Personally (though some soldering required) I’d be looking at getting at least one ISDT q8 and a parallel charge board with your choice of connector along with an external psu (my choice would be a server psu…yes a computer server psu - a single one requires no internal mods for use). Parallel charging is great as long as you are careful…it’s also a lot safer on packs that are used at the same time (such as ran in series in an xmaxx) though I’d probably stick 3/4 on the q8 and do the other one on the d2 myself (assuming you get higher mah packs).

Thanks that is very useful! I will check it out

 

So basically that needs a DC input, hence the server / PC PSU?

 

Isn't looking too expensive either.

 

And yeah the 4S I have on order are 9000mAh also and the batteries will always be used/drained in pairs in my X-Maxx

 

What sort of amps could I charge at with the Q8 if I was doing say 4 batteries, 4S, 9000mAh

 

It would have to be 2 batteries or 4 really, not 3, as I'm using them in pairs - right? So battery A and B might have a different charge than battery C when I'm done using them (if I stopped before the car cut out for example)

 

EDIT: If my maths is correct, charging 4 x 4s 9000mAh would be OK on the Q8 at 7 amps (with a bit to spare) - but.... with the parallel board, that would only be safe if I drained the two pairs of batteries to the exact same voltage? As the Q8 has only one output?

Edited October 22, 2021 by azibux1

[Ross9999992]

1 hour ago, azibux1 said:

 

So basically that needs a DC input

Yeah that’s correct, anything suitably powerful will work and bear in mind you are not limited to 12v. I myself use 2x server psu’s in series (internal work required, not for the feint of heart - similar setups can be bought already done though) outputting 25v. The q8 can actually take an input voltage up to 34v.

 

1 hour ago, azibux1 said:

What sort of amps could I charge at with the Q8

That’s a 20a max charger so up to that 👍🏻
 

1 hour ago, azibux1 said:

It would have to be 2 batteries or 4 really, not 3, as I'm using them in pairs - right?

 

1 hour ago, azibux1 said:

with the parallel board, that would only be safe if I drained the two pairs of batteries to the exact same voltage? As the Q8 has only one output?

Short answer - Yes they need to be the exact same voltage to be properly safe when connecting in parallel.

 

Longer answer - No they don’t 😂
Running them in series will most likely cause each pair to be out of balance with each other slightly anyway (more likely the lower you run them) because there’s no balancing going on. But as they are running in pairs they will at least have the same number of cycles on them. Once they are connected in parallel though they balance off each other. I personally try to ensure any cells I connect in parallel are within .05v of each other (so if I have a cell at say 3.83v I will happily parallel that to another cell at 3.88v~, they would then settle at 3.85v ish) though other sources suggest up to .1v difference is also safe.
 

Tbh yeah I made a mistake (kinda) when I said 3 of them on the q8….it wouldn’t be an issue assuming the voltage safety above but you’d be limited to 20a regardless (18a for 1c on 2x 9000mah 4s packs. 20a for .74c on 3x 9000mah 4s 81~ minutes) So probably 2 on the q8 and 2 on the d2 but you are looking at like .61c on 9000mah 4s @5.5a each to be safe so around 100 minutes.

 

I’ve parallel charged forever (many times over many years) everything from 10+ tiny little 1s 260mah things at a time up to 6x 2s-4s 1300mah - 2200mah up to 3x 5s 5000mah. You just have to be careful to check the voltages (£2 lipo checkers are awesome ☺️)

[azibux1]

6 hours ago, Ross9999992 said:

Yeah that’s correct, anything suitably powerful will work and bear in mind you are not limited to 12v. I myself use 2x server psu’s in series (internal work required, not for the feint of heart - similar setups can be bought already done though) outputting 25v. The q8 can actually take an input voltage up to 34v.

 

That’s a 20a max charger so up to that 👍🏻
 

 

Short answer - Yes they need to be the exact same voltage to be properly safe when connecting in parallel.

 

Longer answer - No they don’t 😂
Running them in series will most likely cause each pair to be out of balance with each other slightly anyway (more likely the lower you run them) because there’s no balancing going on. But as they are running in pairs they will at least have the same number of cycles on them. Once they are connected in parallel though they balance off each other. I personally try to ensure any cells I connect in parallel are within .05v of each other (so if I have a cell at say 3.83v I will happily parallel that to another cell at 3.88v~, they would then settle at 3.85v ish) though other sources suggest up to .1v difference is also safe.
 

Tbh yeah I made a mistake (kinda) when I said 3 of them on the q8….it wouldn’t be an issue assuming the voltage safety above but you’d be limited to 20a regardless (18a for 1c on 2x 9000mah 4s packs. 20a for .74c on 3x 9000mah 4s 81~ minutes) So probably 2 on the q8 and 2 on the d2 but you are looking at like .61c on 9000mah 4s @5.5a each to be safe so around 100 minutes.

 

I’ve parallel charged forever (many times over many years) everything from 10+ tiny little 1s 260mah things at a time up to 6x 2s-4s 1300mah - 2200mah up to 3x 5s 5000mah. You just have to be careful to check the voltages (£2 lipo checkers are awesome ☺️)

Thanks for the very detailed reply! 

 

It's much appreciated 

 

I think you're right two on each would be ideal! 

[Ross9999992]

Ahh no worries, happy to help.

 

This here guide is a how to on converting a single psu should you choose to (oh so easy…jump some pins on the front to make it power on…done). Those are the ones I have in series because I wanted to (that same dude has a guide for that) but a single one is plenty really and really easy to make happen (I have ran like 5 chargers from mine at the same time at one point, 3 at 12v and 2 at 25v) you can pick up referbs from eBay for under £20 which considering the price of “rc” psu’s is a bargain and a half.