Splicing/ connecting charge wires to battery

PRW

100 kW
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Melbourne, Australia
I have had a new battery made, 22S5P Samsung INR21700-40T.

battery 0.jpg

The guy that made it didn't include charge wires. The wires are 2 sets of 10AWG wire. However, I would like to have an external chargepoint, as the battery is in an enclosed frame (i.e. not have to unplug one XT90 set to charge).

How is it best to splice some charge wires in? I looked at creating a Male to 2 Female Xt90 set, but I am not sure how I would fit 10AWG wire together with say 14AWG charge wires into an XT90 connector.

battery 1.jpg

battery 2.jpg

Is it as simple as exposing the existing wire, wrapping and soldering a join with 14AWG wire, and taping it up like the drawing above - or is there a 3 way connector that can be used with relatively high amps?
 
You already have two sets of paralleled leads -- just use one of them for charging and the other for discharging (as intended, most likely). The XT90s are only rated for 40A continuous, 90A instantaneous, so the XT90 will fail (desolder) long before the single 10AWG wire is a problem.
 
You intend to push 20A per cell through nickel strips? What dimensions are they?
 
that was the plan - I don't know the dimensions, I can ask the battery builder (the only guy in NZ I could find to build me a battery, but he has built batteries for others on the forum before)
edit- message from battery guy:
"It is 8 mm by 0.2mm makes it 1.5 mm^2. I tested with 25A through it and the temperature raised from abut 20degC to 35degC in 15 minutes. The 20A is no issue. Voltage drop is not an issue with a length of less than 21 mm. Take also in mind that you run only short burst of 20A (max output) Would like to see you climb a hill for 15 minutes on full power 😊 you will need a mountain for that."
battery 4.jpg
battery 5.jpg
battery 6.jpg
 
"It is 8 mm by 0.2mm makes it 1.5 mm^2. I tested with 25A through it and the temperature raised from abut 20degC to 35degC in 15 minutes.

Something tells me he didn't test it in a closed box.

Closed case means less heat rejection and higher operating temperature. Which means higher resistance and more heat, and so forth.

Be vigilant for funny smells or fumes, hot outer case, etc.
 
Chalo said:
"It is 8 mm by 0.2mm makes it 1.5 mm^2. I tested with 25A through it and the temperature raised from abut 20degC to 35degC in 15 minutes.

Something tells me he didn't test it in a closed box.

Closed case means less heat rejection and higher operating temperature. Which means higher resistance and more heat, and so forth.

Be vigilant for funny smells or fumes, hot outer case, etc.

ok, thanks Chalo, the warning is appreciated. What maximum amps would you recommend running through that setup? The main reason for a new battery was range, rather than top speed/ power - I can limit the amps through the CA
 
PRW said:
ok, thanks Chalo, the warning is appreciated. What maximum amps would you recommend running through that setup? The main reason for a new battery was range, rather than top speed/ power - I can limit the amps through the CA


use temperature sensors on the bms and CA, shove the sensor in the heart of the battery and glue it (or them) in. set the cutoff to 50C/120F. if the cell temp goes above that you need to stop immediately.
 
PRW said:
The reason for the parallel wires is so I can run maximum 100A from the battery (80A max continuous)

Yes, but the parallel wires still pair down to a single XT-90, which is the current-limiting component. The parallel wires may reduce resistive loss, but they are otherwise superfluous. Again, that single XT-90 is only rated for 40A continuous and 90A instantaneous.
 
I'm new to XT90s . I found out that you plug in halfway for the resistor to engage then fully plug in
And they only last so long. they're not meant to be plugged in unplugged and replugged and unplug. When the resistor burns up you can tell.
I have a battery like that but 20s6p Samsung 40t BT. Haven't use it much yet.
 
999zip999 said:
I'm new to XT90s . I found out that you plug in halfway for the resistor to engage then fully plug in
And they only last so long. they're not meant to be plugged in unplugged and replugged and unplug. When the resistor burns up you can tell.
I have a battery like that but 20s6p Samsung 40t BT. Haven't use it much yet.

only the XT90-S with the green stripe on it has the resistor. normal yellow ones do NOT have this resistor.

personal note: XT90 sucks. they cannot do their rated current. anything above 40A is highly dangerous.
 
ok, the warning on XT90s is noted, thanks fatty/ flippy.

what do people use to run 80 amps plus - XT150s, or it there an alternative?
 
PRW said:
ok, the warning on XT90s is noted, thanks fatty/ flippy.

what do people use to run 80 amps plus - XT150s, or it there an alternative?

you bolt connections with pressed on (so no solder!) ring lugs.
if you have to takr them out often you use a single xt60 or whatever that only does the precharging resistor and then real (so no chinese) SB75 or bigger anderson connectors so you dont damage the connector or kill the controller with sparks.
 
flippy said:
you bolt connections with pressed on (so no solder!) ring lugs.
if you have to takr them out often you use a single xt60 or whatever that only does the precharging resistor and then real (so no chinese) SB75 or bigger anderson connectors so you dont damage the connector or kill the controller with sparks.
great, thanks, I didn't know any of this
 
compare an SB50 with a XT90 and tell me the first thing you notice.

bear in mind that the SB50 is rated 35 amps (aka: basically half!) LOWER then the XT90....
 
flippy said:
compare an SB50 with a XT90 and tell me the first thing you notice.

bear in mind that the SB50 is rated 35 amps (aka: basically half!) LOWER then the XT90....
I guess the sheer size and quality of the SB50....
 
PRW said:
what do people use to run 80 amps plus - XT150s, or it there an alternative?
Anderson SB connectors, or QiangShui QS8-S if you need anti-spark
 
the plot thickens...

the controller I am using has wires to the battery much less than 10AWG (3.4mm2). It is rated at 70A (I have been running at 60A max via the CA). The wires have no "AWG" markings I can see. This controller was used with my previous 22S5P 30Q battery.

How have these wires survived 5 years?
control 2.jpg

control 3.jpg

controller 1.jpg

Also, I was intending to get a 24F Nucular when available, to have no stress on the controller. This uses 8AWG wire - but yet 300A battery max?
 
did you consider the specs are bullshit?
 
cables can take a lot of amps for a short while, until they heat up. but generally at that point the current has already dropped enough.

its certainly not the way its supposed to be done but companies that make crappy products simply use the buffer that real life usage provides.

there is also no way that controller will survive 80A for longer then a couple seconds.
 
PRW said:
flippy said:
did you consider the specs are bullshit?
Do you mean the ZL controller? It's possible, but it has been running at 60a max with no issues?

and... I have no idea about the Nucular

I have ( a few of) the same controller but it is 96v, 55A, and the wires are much larger.... 10mm^2? Somewhere round there.. Just like the gauge of a QS205V3... SAme gauge as my Lyen 24FEt, or maybe a tiny bit less. Aside from that, looks identical to your 48v 70A. I have opened it and it has big shunts (4 I think) and decent spec transistors Fet banks. ( label).

Yours have a weird BLUE LED hanging off it? Mine do.
 
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