External connectors for a LiFePO4 battery box (anderson, XT-60)?

trae

Adventurer
Hello everyone,

Building a LiFePO4 battery box. The box will be self contained and move between various vehicles. I anticipate having the following external connections:

- USB/12v cigarette (these are easy enough)
- Solar In (to a solar charger that lives inside the box)
- Mains in (to charge in the house)

I'm aiming for 300 watts max (or 30A @ 12v).

My question is about the actual physical connectors. I know anderson gets a lot of praise here, but the physical profile concerns me -- it looks like they take quite a bit of space.

The other option is an XT-60 (or an XT-90) connector. My concerns about weather resistance and life cycles. They are not the best to plug/unplug repeatedly.

What would you recommend? Are there any builds that I can look at for inspiration?
 

hour

Observer
I regret doing XT60 because of the limited availability of panel mount connectors. It made sense with all of my hobby chargers being XT60, but it would have made more sense to just build an XT60->Anderson cable in a couple of minutes.

You can buy XT60 packages with boots on the back but your soldering job has to be perfect (leads coming off straight) or they won't go through the boot. That problem is compounded if you add your own heat shrink to the wires before trying to push the boot up.. but if you can pull it off they're a pretty nice fit and I don't have any concerns of water seeping in behind. I also think their mating connections form a better seal than Anderson.

What I did for a similar portable self contained box (the one I avoided XT's on) is: dual power pole panel mount connector w/ dust boot ($20) - with the bottom powerpole oriented in a non-traditional manner. That's for charge input. You could probably do the same and save some headache since your charge controller is onboard. I can plug solar or a 24v 10 amp DC adapter brick at home (or from generator) that I chopped the end off and added a powerpole connection to. That goes to the bottom wonky powerpole, impossible to mix up. Saved me money not having to buy a Lifepo4 charger, many of which have no adjustability. Also made bench testing easy as hell. One charger, one profile, any power source above 18v.

I didn't know there was any issue with XT connectors being plugged/unplugged a lot, there's less going on there than with the springy contacts of the powerpoles. I think that's a benefit of the powerpoles though, the contacts grind against each other any time you connect/disconnect and that mitigates gunk.

Oh yeah, here's another argument for powerpoles, specifically the dual powerpole thing I mentioned above. You get an extra discharge port in addition to your cig lighter-usb thing that's more reliable and capable. Just pop em out and orient one different. Not pictured: rubber boot. I'd recommend buying official connectors from the Powerwerx store, the Amazon generic ones seem to overstate their current carrying capacity (per reviews). I still use them for small loads.. AKA I would not try to run 20 amps through a 30 amp generic powerpole. And if I were charging @ 30 amps I'd definitely use the 45 amp official powerpoles. Get the proper crimping tool.

Last thing... the dimensions. Yeah, the power poles stick out a bit more if plugged in to the side of the box than an XT60 would to a panel mount receiving end. It's best to not bump any connector, but after you heat shrink an XT60, and with some solder having flowed through the wire, it still has a largely non-flexible end that won't appreciate being knocked in to.

 

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dreadlocks

Well-known member
will it have an AC/DC charger inside you needing to feed 120v into or are you gonna feed the solar charger w/a high voltage DC charger? that gets rid of one external plug right there.. now you just have DC in/out and for that, andersons..
 

jonyjoe101

Adventurer
I got xt60 connectors on everything for the past 8 years, they are on my 220ah lifepo4, on my smaller 31ah and 65ah lion packs, i got them on my fridge my roadpro cooker, all my chargers. They are inexpensive and easy to put together with a solder gun. Some of the clones are hard to take apart, and then they have the original amass brand which always come apart without too much effort, I use different types xt60 over the years and most worked good. I always buy a small amount to test out before I buy a large qty. I also use the xt90 on my jump packs.
I also use the andersons before but they are more expensive and larger and I didn't see any features that made it better then the xt60.

xt60 connector large a.jpg
 

DaveInDenver

Expedition Leader
I didn't know there was any issue with XT connectors being plugged/unplugged a lot, there's less going on there than with the springy contacts of the powerpoles. I think that's a benefit of the powerpoles though, the contacts grind against each other any time you connect/disconnect and that mitigates gunk.
I haven't used the XT60 extensively and finding information of them isn't completely straightforward.

AFAIK the real ones are made by AMASS in China and they don't seem to offer much on their website or specification documents that I can find in English.

This I think is the OEM website: http://www.china-amass.com/product/index?r=product/index&query=0_14


Screen Shot 2020-07-08 at 5.21.50 AM.png


Screen Shot 2020-07-08 at 5.22.05 AM.png

But this web site points to an AMASS document as well: https://www.tme.com/Document/2d152ced3b7a446066e6c419d84bb460/XT60 SPEC.pdf

So it seems they are rated for either 100 or 1,000 mates and have either 0.55mΩ or 0.60mΩ of contact resistance. Contacts are gold plated brass. Max current may be 60A or the similarly used instantaneous current is 40 amps. They are rated (e.g. I take this to mean continuous) for either 20 or 30 amps. Both documents agree that 120°C is their max temperature.


PowerPoles: https://www.andersonpower.com/us/en/resources/PowerPoleResourcesPage.html

Anderson rates the PP15/45 (smallest housing is what we typically use) tin plated contacts for 1,500 mate cycles and the silver plated contacts for 10,000 mate cycles.

Avg. Mated Contact Resistance:
15A Wire Contact with 5/8” of #16 AWG - 0.875 mΩ
30A Wire Contact with 5/8” of #12 AWG - 0.600 mΩ
45A Wire Contact with 5/8” of #10 AWG - 0.525 mΩ

The PowerPoles are rated based on continuous current with a temperature rise and ambient derating using a baseline of 25°C ambient. The largest PP15/45 contact with 10AWG cable appears to be rated to carry 55A following UL (absolute max 105°C) or 40A following CSA/TUV (30°C rise).
I'd recommend buying official connectors from the Powerwerx store, the Amazon generic ones seem to overstate their current carrying capacity (per reviews). I still use them for small loads.. AKA I would not try to run 20 amps through a 30 amp generic powerpole. And if I were charging @ 30 amps I'd definitely use the 45 amp official powerpoles.
The question of authenticity is always important with Amazon regardless of what you're buying IMO. That's even true with Amazon as the seller but certainly true when they are only the market provider.

Powerwerx sells legitimate Anderson for 15A, 30A and 45A sizes but there are other sources.

FWIW, the ~40A rating seems appropriate. From what I've seen even the open barrel (12 & 10 AWG) PP45 can get fairly warm such that with my Iota DLS-45 (e.g. 45A rated max) charger I prefer to use the larger Anderson SB50. So the PP75 sharing the same contacts as the SB50 would also give some margin.
 
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DaveInDenver

Expedition Leader
BTW, one thing to consider is safety. The XT60-F (female, the right one) is shrouded against being shorted so that should be the power or battery side. I don't know which pin is positive vs negative, I assume there is a standard for this.

10474-02.jpg
OTOH while PowerPole are intrinsically safe from sticking a screwdriver or finger on both power and load side it's possible to get multiple poles configured incorrectly. What is "right" or "wrong" kind of depends on context. As long as you're consistent you'll be OK.

But the ARRL defined a standard for use in ham radio some years ago. This was originally to guarantee uniformity with all equipment you might encounter during emergencies, SAR, packet radio, etc. Therefore for a nominal 12V connection they recommend red and black colors using this orientation and thus is the de facto "right" simply because most commercially available power supply, panel, device, jumper cable, etc. you find will be assembled this way. But there's nothing really forcing you to do this way.

iCSAr.png

You'll notice there's a little roll pin in the middle of an assembled PowerPole pair. I generally try to remember to put that in so the two connectors don't get pulled apart and risk being put back together wrong. Anderson themselves make red/black pairs that are bonded permanently. Essentially they melt them together during manufacturing and it's impossible to separate them without breaking the housings.
 
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dreadlocks

Well-known member
yeah I like that andersons can be keyed and re-keyed on the fly.. If you have a DC input and a DC output from your bank you can make one horizontal and one vertical or vice versa.. good for when you got 2 pigtails coming out of the battery with different voltages for solar and battery, no accidently hooking panels up directly to the battery and if you have a spool of extension cable you can make it either high voltage or low voltage keyed in the field in a couple seconds.

You can also choose to put locks into the plugs that prevent them from separating with a yank if the load is critically important, or leave em yank-safe if someone trips over a cord it wont damage anything.. the plugs are self cleaning so if you drop one into the mud its no big deal.

Andersons all day, every day.. i put it on everything but my USB Chargers, those I keep 12v Ciggy plugs around just because the standards are always changing and the USB chargers reliability is often questionable.
 

DaveInDenver

Expedition Leader
Good point about assembling horizontally vs vertically. I'm partially color blind so using black and another color for USB/5V will only make sense to me since greens and yellows kind of look similar and wouldn't necessarily look right to everyone. Red and black might even look like grey and black to someone. So I still use red and black for 5V but assemble the positive upside down so the terminal tongues aren't the same orientation. I imagine you could do similar tricks to differentiate 12V from 24V, etc. I've also thought about reversing positive and negative so that if you plug a 5V device into 12V it would blow the reverse polarity protection. But this isn't always going to be present and seems like a risk to rely on.
 

dreadlocks

Well-known member
yeah there's a ton of ways to uniquely key up andersons to prevent anyone from accidently plugging the wrong things together, rotating the plugs in all sorts of orientations.. all sorts of colors you can get too (but as you pointed out colorblindness could screw up the best plans).. and when you work your way up to the big andersons you still retain unique keying capabilities even though their design is significantly different.

Also if you need more than 1 pair of wires, like 3+ for a custom wiring harness for plugging in a reverse camera or something you can build what you need without jumping ship and finding yet another connector type to throw into the mix, adding more tools and spares to your field repair kit.
 

trae

Adventurer
Thanks gents this is a useful discussion. I read that XT-60 have a 1000 cycle life, but Anderson doesn't seem to have much more at 1500 so I dont think that's a serious consideration.

I found a male flushmount XT60. No dust cover and @DaveInDenver point about the contacts being exposed is very relevant:

1594237538463.png


For anderson power poles, can I get around buying a crimper? I expect to use this once or twice at most. I'd hate to buy a $50 tool for that.
 

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Verkstad

Raggarkung
I don't know which pin is positive vs negative, I assume there is a standard for this.
Notice the connectors are keyed to mate, ’squared off’ side is positive, beveled edge side negative.
For anderson power poles, can I get around buying a crimper?
Nothing ”wrong” soldering Anderson connectors. Typically its not allowed in industry but for a guy building one-offs, Compentent soldering is perfectly serviceable.
 

DaveInDenver

Expedition Leader
For anderson power poles, can I get around buying a crimper? I expect to use this once or twice at most. I'd hate to buy a $50 tool for that.
In PP15/45 there are 3 options for terminals, the left two are the 15A and 30A and referred to as closed barrel. IIRC, they can be crimped or soldered according to Anderson with the caveat I believe is either but not both crimped and soldered (good general rule anyway).

The one on the right is the 45A and is called an open barrel which can only be crimped.

iu.jpeg

I have crimper dies for all three of the PP15/45 terminals as well as PP75/SB50 so haven't soldered them in ages. To me the proper crimpers are a variation on an F-crimp, the difference being the length of the crimp.

So any tool that can make up Molex, Tyco, Deutsch or similar terminals can probably be used. Best would be a tool that only does one crimp at a time rather than a single press tool that crimps both the conductor and insulation at the same time.

IMG_0070_mid.jpg

IMG_0069_mid.jpg

If you're not in a position to get decent crimper for a couple, yeah, just have someone do it for you. Hint, I'm in Grand Junction, CO...
 
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