Powe loss with Tamiya connector: yes or no?

[skom25 2179]

Hi,

Before someone will write "just use Deans/ XT" plug, I want to answer that. Yes, normally I would use mentioned plugs and do not care. I even have them in TT-02.

I need NiMh packs for my XV-01. As you can imagine, battery replacement is very, very hard. I need two hands and head (!) to replace pack.

I like Tamiya connectors, because they are super easy to plug/ unplug and process of battery replacement in XV-01 is bit less painful.

However, I wonder if there is real power loss when Tamiya connectors are used, compared to e.g. Deans.

If yes, I will choose Deans and make my life harder. If no, there is no reason to do this.

Any comments?

 

 

[scoobybooster 342]

First of all, even if it is probably clear: every plug connection is also associated with (voltage) loss and therefore also power loss. 
However, many factors play a role in this, it is not just a question of the connector system. Cable thickness, material, temperature, etc. are all factors that play a role.
In general terms, it can be said that the popular Tamiya connector is certainly sufficient for NiMh batteries and the associated current flow, but is no longer sufficient for more powerful battery packs in LiFe or LiPo technology. For this reason, LiPo/LiFe are usually equipped with Deans or higher quality connector systems, especially in high voltage constellations (i.e. not just 2S packs), which are designed to keep this voltage loss as low as possible with high-quality materials such as silver or gold contacts.
Long story short: for NiMh Tamiya yes, for LiFe/LiPo better Deans or higher quality connectors

[skom25 2179]

Thank you!

I thought more about comparison like:

Power loss on Deans: 0,5%

Power loss on Tamiya: 5%

Of course this is just example and I do not expect that numbers are even close to this above.

I know that probably it is not so easy, but it is more about scale. If difference between both is marginal, I do not see reason to make my life harder.

[scoobybooster 342]

You can't answer that because the behavior is not linear.
The higher the current flowing, the greater the differences.
If you only draw 2 amps of current, there is hardly any noticeable difference. At 20 amps, it's a different story - and so on...
 

[Losi XXT-CR 469]

2 hours ago, skom25 said:

Hi,

Before someone will write "just use Deans/ XT" plug, I want to answer that. Yes, normally I would use mentioned plugs and do not care. I even have them in TT-02.

I need NiMh packs for my XV-01. As you can imagine, battery replacement is very, very hard. I need two hands and head (!) to replace pack.

I like Tamiya connectors, because they are super easy to plug/ unplug and process of battery replacement in XV-01 is bit less painful.

However, I wonder if there is real power loss when Tamiya connectors are used, compared to e.g. Deans.

If yes, I will choose Deans and make my life harder. If no, there is no reason to do this.

Any comments?

 

 

Go XT60, way nicer plug to use than Deans IMO. I have XT60 and an XV-01T.

The Tamiya connectors can fail under load. I didn't believe it until I saw it. And that was 30 years ago using a NiCd pack.

[Saito2 7654]

I've been using Tamiya/Molex plugs for close to 40 years at this point. They do eventually wear out and this shows up in high load situations first. The male pins are actually 3 strips of metal and can compress over time. Tamiya even instructs the user in one of their guide books to carefully insert something in the center of the pin to spread them out slightly every so often. The female ends can get wallowed out over time too. I was noodling around with an old Emaxx (14.4 volt) about 20 years ago and it quit running suddenly. The heat generated from the old connectors had allowed the male pin to melt the connector internally and slip out of the female end it was precariously attached to. Of course the outer connector housings were fused together as well. Fun. Now, I just keep an eye on them, spread the male terminals occasionally and replace them as needed. Keep in mind, I'm strictly a brushed/Nimh guy (which means I'm due for a browbeating from the Lipo crowd and possibly the connector police for not "RC-ing" correctly, lol j/k).

[skom25 2179]

1 minute ago, Saito2 said:

I've been using Tamiya/Molex plugs for close to 40 years at this point. They do eventually wear out and this shows up in high load situations first. The male pins are actually 3 strips of metal and can compress over time. Tamiya even instructs the user in one of their guide books to carefully insert something in the center of the pin to spread them out slightly every so often. The female ends can get wallowed out over time too. I was noodling around with an old Emaxx (14.4 volt) about 20 years ago and it quit running suddenly. The heat generated from the old connectors had allowed the male pin to melt the connector internally and slip out of the female end it was precariously attached to. Of course the outer connector housings were fused together as well. Fun. Now, I just keep an eye on them, spread the male terminals occasionally and replace them as needed. Keep in mind, I'm strictly a brushed/Nimh guy (which means I'm due for a browbeating from the Lipo crowd and possibly the connector police for not "RC-ing" correctly, lol j/k).

I use NiMh with Silver Can/ Torque Tuned/ Sport Tuner. Nothing more.

I had Super Stock for a while, but it is waste of money.

[Saito2 7654]

15 minutes ago, skom25 said:

I use NiMh with Silver Can/ Torque Tuned/ Sport Tuner. Nothing more.

Same here .

[Rijkvv 66]

1 hour ago, Losi XXT-CR said:

Go XT60, way nicer plug to use than Deans IMO. I have XT60 and an XV-01T.

The Tamiya connectors can fail under load. I didn't believe it until I saw it. And that was 30 years ago using a NiCd pack.

I'm afraid the XT60 connector is too big to fit the hole to the battery compartment in an XV01. Maybe you can modify it, but it was reason for me to get a converter connector Deans>XT60.

I didn't care too much about power loss, but I've had the Tamiya connectors disconnect quite a number of times already, with the wires themselves getting out of the connector itself.

[skom25 2179]

Yes, XT-60 will not fit XV-01. NiMh packs are not available with XT-60 plug. I can choose between Tamiya and Deans.

Of course they can be switched, but I do not want to do this. I do not have problem to solder wires, plugs, motor cables etc, but battery is bit different level of risk.

[Losi XXT-CR 469]

33 minutes ago, Saito2 said:

I've been using Tamiya/Molex plugs for close to 40 years at this point. They do eventually wear out and this shows up in high load situations first. The male pins are actually 3 strips of metal and can compress over time. Tamiya even instructs the user in one of their guide books to carefully insert something in the center of the pin to spread them out slightly every so often. The female ends can get wallowed out over time too. I was noodling around with an old Emaxx (14.4 volt) about 20 years ago and it quit running suddenly. The heat generated from the old connectors had allowed the male pin to melt the connector internally and slip out of the female end it was precariously attached to. Of course the outer connector housings were fused together as well. Fun. Now, I just keep an eye on them, spread the male terminals occasionally and replace them as needed. Keep in mind, I'm strictly a brushed/Nimh guy (which means I'm due for a browbeating from the Lipo crowd and possibly the connector police for not "RC-ing" correctly, lol j/k).

I'm sure they can be fine. although somewhat surprised Tamiya hasn't updated the conector.

The failure we had must have been around 1996-1998 at a guess. 2wd stadium truck in longish grass. It was a Tamiya NiCd battery, so I'd guess a 1300 or 1500mAh. And something like a 15T brushed motor. Nothing extreme. The model ran for a few mins, then stop and wouldn't do anything. The plug had melted and fused the battery end to the ESC end. We had to cut the wires to "turn it off" as it wouldn't unplug. We swapped to Power Pole connectors, which is what we used to run back then. The XT60 is so much nicer though, maybe a little more bulky, but I've not had an issue with the size of the connector in any model, including aeroplanes.

[alvinlwh 7227]

Didn't you ask the same question a year ago? 

[Losi XXT-CR 469]

11 minutes ago, Rijkvv said:

I'm afraid the XT60 connector is too big to fit the hole to the battery compartment in an XV01. Maybe you can modify it, but it was reason for me to get a converter connector Deans>XT60.

I didn't care too much about power loss, but I've had the Tamiya connectors disconnect quite a number of times already, with the wires themselves getting out of the connector itself.

 

7 minutes ago, skom25 said:

Yes, XT-60 will not fit XV-01. NiMh packs are not available with XT-60 plug. I can choose between Tamiya and Deans.

Of course they can be switched, but I do not want to do this. I do not have problem to solder wires, plugs, motor cables etc, but battery is bit different level of risk.

Afraid I disagree as I run XT60 connectors in my XV-01T. I didn't have to modify the battery tray or chassis, they just slip through the hole. I did modify the ESC tray/housing, but I had too anyway as I run a 9T brushless system in it.

As for buying with the right connector, handy if you can. But just solder on a connector of choice.

Deans/T-stye are ok, but can be fiddly to unplug. Quality is also highly variable. The XT60's seem much more consistent and you can plug an EC5 battery into an XT60 ESC, which is also handy.

[markbt73 5850]

Sometime back in the 80s or 90s, RC Car Action magazine actually load-tested a bunch of different connectors to find out how much loss there was. At the time, I think the champion was Anderson Power Poles, which actually had a lower resistance than straight 14 gauge wire. Deans Ultra Plugs were right up there as well. I don't remember exactly what they said about standard Tamiya connectors, but it was something along the lines of "not as bad as we expected."

Back then, we were trying to get every last electron out of a battery to win races, because the batteries were terrible. Now, with massively better batteries (yes, even NiMH have improved a whole lot) and far more efficient ESCs, I doubt that a little loss matters as much. Just use what's convenient, and don't worry about it.

[BuggyDad 5904]

7 hours ago, skom25 said:

I need NiMh packs for my XV-01. As you can imagine, battery replacement is very, very hard. I need two hands and head (!) to replace pack

Is it? I find it straightforward, not really worse than anything I have to unclip a body on. 

[DearHighRacingClub 23]

It's extremely difficult to measure the actual resistance in different connectors, we're talkiing milli Ohms here. Even straight soldered wires with no connectors have resistance. Modern high performance motors can draw more than a 100A and for that the wires really should be more than 20mm2. But that is not really doable irl

Takes very expensive lab equipment to measure anything like that btw

What we're talking about is how these different connectors works with repeated use and abuse. And this is where TC members know much more than me

Now, I'm a 3000mAh NiMH/Sports-Tuned motor kinda guy so the "Tamiya connectors" are just fine for me, however those Molex connectors where never intended to pass peak currents of plus 30-40 Amps

I used to sell a lot of those Molexes in a former job and the rule-of-thumb was 5A for the small ones 10A for the big ones (the "Tamiya connectors"), that being continous rating ONLY

Interestingley, theres actually a wiki

Cheers,

Ole

[Rijkvv 66]

5 hours ago, Losi XXT-CR said:

 

Afraid I disagree as I run XT60 connectors in my XV-01T. I didn't have to modify the battery tray or chassis, they just slip through the hole. I did modify the ESC tray/housing, but I had too anyway as I run a 9T brushless system in it.

As for buying with the right connector, handy if you can. But just solder on a connector of choice.

Deans/T-stye are ok, but can be fiddly to unplug. Quality is also highly variable. The XT60's seem much more consistent and you can plug an EC5 battery into an XT60 ESC, which is also handy.

I wanted to ask what your secret is, and had to get my XV-01 to test it. Turns out I have two different types of XT60: one with just a housing of which I bought a bunch to solder myself. This one just fits diagonally through the hole. Another one was soldered as a replacement connector of an ESC by a webshop and came with a grey "collar" which doesn't require a heat gun to shrink. This one is more rounded and works well, but I couldn't find any way to pass it through the hole.

I wanted to post a picture, but can't seem to upload it.

[Losi XXT-CR 469]

1 minute ago, Rijkvv said:

I wanted to ask what your secret is, and had to get my XV-01 to test it. Turns out I have two different types of XT60: one with just a housing of which I bought a bunch to solder myself. This one just fits diagonally through the hole. Another one was soldered as a replacement connector of an ESC by a webshop and came with a grey "collar" which doesn't require a heat gun to shrink. This one is more rounded and works well, but I couldn't find any way to pass it through the hole.

I wanted to post a picture, but can't seem to upload it.

I know the connector you mean. I don't have any like that, just the regular XT60's, many I've soldered myself. 

[Losi XXT-CR 469]

3 hours ago, BuggyDad said:

Is it? I find it straightforward, not really worse than anything I have to unclip a body on. 

The XV-01 has a terrible battery tray, about the worst I've seen on any RC ever, you need a screwdriver to open the cover ffs!!! But I agree, you shouldn't need to use your head. But certainly it is a two handed job. I've now resided to leaving a pack permanently in mine and have poked the balance lead up through next to the ESC, so I can charge it in situ.

[skom25 2179]

6 hours ago, alvinlwh said:

Didn't you ask the same question a year ago? 

Probably I asked if I can use Tamiya connector with XYZ motor, not difference between mentioned plugs.

[Andreas W 2509]

Power loss and power loss... In the OP's case here the biggest gain is to have a connector that takes up the least amount of space. In that case Deans (the variant which only is using shrink wrap is compact and nice. In my case I don't know if the previous owner had modified the hole in the chassis (he had modified it all round to gain ground clearance), but in mine a Deans connector went straight through. The easy solution is to cut off the Tamiya connector, slide the cables through before you tape the ESC and solder the connector, though. Then it does not matter if it goes through or not. 

 

I've had a few problems with the Tamiya connector as described by Saito2 above and was the reason why I switched. I was still on NiHm at that time and because Deans was the most common connector here the choice was obvious. Later I have experienced differences in quality in the connectors. In some of the models I have used bullet to Deans adapters there has been quite a few occations with bad connection - much similar to what I had with the Tamiya connectors. Since I mostly run hard case batteries with bullet connectors I have soldiered on bullet connectors and it's all peace and quiet now. But that would be the next stage, when taking the leap over to LiPo. 

 

BTW an 8,4V pack goes into the XV-01, if you want to get almost LiPo performance for a few minutes. It's quite a difference and a lot of fun when the TT (or a ST) wakes up. 

[skom25 2179]

8 minutes ago, Andreas W said:

that takes up the least amount of space.

Surprisingly, it is not an issue with 3300 and even 4000 mAh packs I have.

Whole process is bit annoying, because I do not want to put car on the roof, to replace battery. When I remove body, I do not want to put in on body post... In that case, I hold it in one hand, remove cover, place battery and... I need third hand to plug in connector. So I put it vertically, hold with my head and connect battery.

This battery tray design is really weird.

[Andreas W 2509]

In the beginning I did not like the battery compartment solution either, but now I do. I lay the car upside down in the lap while sitting on the knees. I now like that I don't ned to take off the body to put in the battery. It's handy when it's windy. I have not had runaway body due to wind,  but had it a few times with markers. Not nice when the marker is heading full speed towards the heavy trafficed E18.

 

[BuggyDad 5904]

Yes, my opinion of the battery door idea does depend on you having a surface to place the car on upside down that won't scratch it. Or a beater body. I have both. But when you do I think it's a decent solution. For me, I'm usually back in the house to change a battery anyway, or I'd have my car. 

Genuinely though, and especially if you have an electric screwdriver in your rc toolbox that's with you anyway (which I think is well worth having for other reasons) then the XV-01's battery door might even overtake traditional methods for convenience. 

I also started with a negative view on it. 

[skom25 2179]

Just to be clear. I think it is great idea from perspective of battery protection, tidy wiring etc. This is why I like XV-01 so much.

It is just bit uncomfortable, because I do not want to damage body.

I decided to not overthink this and just ordered the same pack as I have now with Tamiya connector. It is not a problem, to use sharp tool to widen plug a bit, so fitment is much tighter.

I also found that NiMh with Deans are not very common now. There was moment when I saw a lot of them, but now again most are with Tamiya connector.

At the end, I can easily swap connector on ESC and just ask for connector replacement in LHS.