extending battery temp sensor wires on Mppt

[coachgeo]

did search some first... if there is a topic thread on this I missed please do point it out.

would like to modify the battery temperature sensor. Whole inside of my controller is a solid mass of epoxy cause it is IP68 (dust/waterproof). In typical use; this type controller is used sitting next to/nearby the battery so a little temp sensor tail sticking out the back into the air works perfect.

I've a habit of never doing things typical though LOL I want to have these not by the battery.

Any electrical wizards see an issue in snipping the tail off in the middle and extending the wires 25ft or so to the battery and re-attach the sensor? Going to Lead battery for now... though in future that may change to LiPo4.

If not an issue.... could the heat of soldering harm the sensor?

 

[mikefitz]

The idea of mounting the controller as near as practical to the battery is to reduce volt drops and thus have correct charge control.
Temperature compensation of charge voltage in needed for lead acid, but not for lithium.
The usual resistance value of the sensor is high, typically 10k ohm, so any cable you add will have no real effect.
Heat should not effect the sensor and you could use pliers/pincers holding the sensor cable to act as a heat sink whilst soldering.

Mike

 

[coachgeo]

The idea of mounting the controller as near as practical to the battery is to reduce volt drops and thus have correct charge control.
Temperature compensation of charge voltage in needed for lead acid, but not for lithium.
The usual resistance value of the sensor is high, typically 10k ohm, so any cable you add will have no real effect.
Heat should not effect the sensor and you could use pliers/pincers holding the sensor cable to act as a heat sink whilst soldering.

Mike

Yep ...... lead batts. One thing at a time

thanks.... so it the becomes a math-dollar game:

Ive got five 24v 10amp controllers each will mate with its own 24v panel arrangement (long story.. but it is what I have). so dollars per foot of wire types/gauges throws one into what may be best scenaro question....

1. the controllers (water/dust proof type) near panels and have each controller(s) charge outputs paralleled so can send one wire to the battery bank *placed far away. High enough gauge wire to avoid voltage drop. As well extend their temp sensor(s) with fairly small gauge to the battery area too (also parallel or each individually orr?) (less wires but larger)
2. run each controllers charge output separately down to the banks. Same with the temp controller (smaller gauge for charge power but 5 of them)
3. Put controllers in a cabinet traditional way with batts and run each solar panels output to its controller in the cabinet (lot of wires again but smaller gauge than #2 choice.)

In all those could negative be combined?

something else better?

what is your experience?

*far away is relative.... its only a 14ft long camper with Panels on top.

 

[coachgeo]

have messaged a couple of vendors about their controller with a similar temp sensor dongle on them to gather info... will be a miracle if they reply ... if they do; will report back.

asked if :
> the sensor was primary for modulating charge output to protect the controller based on temperature or primarily to protect the battery
> was it required to mount the unit in close proximity to the battery
> is it a J or K thermocouple or a 10k thermister orr?

Reply

 

[coachgeo]

this might be a solution. leave the dongle since dont know really what it is... leaning my thoughts toward it limits charge output to not cook itself when hot.... maybe it limits it when cold... will see what doccumentations says..... but if it does not.. here is a potential way to add battery temp control externally... This fella did it for LiPo4.. though BMS could handle that for most... he does not have bms looks like..... but myself Im going (for now) into lead.... so need little more control since lead has no bms

 

[coachgeo]

if this helps.. another seller with very similar dongle on their controller responded with below information

​

Hi, 1. This sensor measure the ambient air temperature to adjust charging so it helps charging the battery well. 2. It's not measuring battery surrounding temperature. 3. We don't have this requirement. (to mount battery near controller) 4. It's 47K thermal resistance sensor, Negative Temperature Coefficient​

 

[coachgeo]

an electronics supplier is 90% confidient it is a NTC thermister (NTC = Negative Temperature Coefficient)
he gave me a test to see what "K" they are so he can advise further. Will do once it arrives from china