Connecting RTS 3.5 years later

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rpbancroft
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Posts: 41
Joined: Mon Oct 29, 2018 10:41 am
My RE system: VFXR3524A inverter, FlexMax 80 charge controller, Mate3s

Connecting RTS 3.5 years later

Post by rpbancroft »

Hi there,

I was just curious what you all's thoughts are on connecting an RTS 3.5 years after my system was put into use? Is it a no-brainer, or should I be aware of some issues that could occur? Will it even help given that my AGM batteries haven't gotten that treatment this far into their lives? If it's useful to know, my batteries are within the conditioned space, but they rarely sit at 75 degrees for several reasons (the floor gets pretty cold, and they're directly against it; we only heat to 66, and I'd say the floor is closer to 63; they might run near 75 in summer though; etc.).

The people who built our house purchased one but forgot to connect it, and I've been (probably foolishly) dragging my heels on finding a way to run it the 35 or so feet through the interior of my tiny house (when it should've gone through the walls with the other wires). However, we've been recently having some low voltage issues with our batteries (I'll ask about that in a separate topic), and I suspect they're at least somewhat linked to the lack of voltage modulation based on temperature.

Thanks so much for your thoughts!

~Ryan
rpbancroft
Forum Whiz
Posts: 41
Joined: Mon Oct 29, 2018 10:41 am
My RE system: VFXR3524A inverter, FlexMax 80 charge controller, Mate3s

Re: Connecting RTS 3.5 years later

Post by rpbancroft »

Oh, I'm also curious if it's okay if I extend the cable of the RTS? As I think I mentioned, I have to run it about 35', which is longer than the supplied cable. I was planning to just use a length of Cat5e cable (which would plug into the HUB's port 1) and an RJ45 coupler.
raysun
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Posts: 7762
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Connecting RTS 3.5 years later

Post by raysun »

If one is going to err in charging AGM, erring on the undercharged side is preferable. The cooler battery would likely be undercharged.

The brand/model of AGM isn't mentioned, but in general, temperature compensated charging is a good thing.

In the system listed, the RTS would actually plug into a special port on the inverter. The inverter's OB communication port would be plugged into Port 1 on the Hub. In that way, Tenp Comp data would be shared with the FlexMax charge controller.

The RTS is a precision thermistor, a temperature variable resistor of sorts. Adding extra wire is likely to add extra resistance to the RTS, likely skewing its output.

Is the inverter really 35' away from the battery?
rpbancroft
Forum Whiz
Posts: 41
Joined: Mon Oct 29, 2018 10:41 am
My RE system: VFXR3524A inverter, FlexMax 80 charge controller, Mate3s

Re: Connecting RTS 3.5 years later

Post by rpbancroft »

Well that's good at least, probably means I haven't prematurely fried (or frozen?) the batteries for this particular reason at least. :P

The batteries are Centennial brand, CB12-260, if that helps.

Thanks for the confirmation on where to plug in the RTS. I was watching Outback's how-to video and wasn't sure if I should use port 1 in the HUB or that port on the inverter. I'll have to check my Mate3s to see if port 1 already is servicing the inverter. Likely it is and the sharing process with the other systems (charge controller and Mate3s) will work through that... I'm guessing?

For lengthening the cord... darn. I was afraid of something like that. Straight line, it's probably about 24' away, but if I want to route it behind cabinets and behind our fridge (the only reasonable method given our house's layout) and attach it to the colder battery box, I suspect it'll work out to somewhere between 30' - 35'.

Any recommendations in that apparently really unorthodox situation? The main reason we had it done this way is that it's a tiny house on wheels, and the ~1500lbs of batteries had to be on that side of the house for internal weight balancing while moving the structure.
raysun
Forum Emperor
Posts: 7762
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Connecting RTS 3.5 years later

Post by raysun »

Understood.

Grab a stiff drink and read my other very cheery post on AGM state of affairs.
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