Does anyone have any experience with these units? I was advised to get one to modify the charging voltage based on the battery temperature. So I have 2 installed, one for each MPPT. What is nice is that the measure voltage much better than the MPPT by itself so the BMV and both MPPTs are very close. My batteries need the voltage adjusted by 0.005V for every degree away from 25C. But I can't figure out if the settings are right, and Microcare is not being helpful. 

http://microcare.co.za/wp-content/uploads/2014/11/Programmable-Relay-Manual-Ver-RPR-2016-1-C.pdf

The manual says this, but I cant't see how to adjust the voltage increments? :

 

 

 

The display is as below, so it seems to be working, and measuring the temperature correctly. 

So it appears to be adjusting the voltage down by 0.4V. 

Is this correct? The battery specs are below:

0.005V x 24 cells? x 1.1 degrees = -0.132V?

Edited March 19, 20196 yr by DeepBass9

Have you spoken to Scott about this? He's really clued up and normally very helpful. 

Apparently he has left and I have no response from anyone else.

23 minutes ago, DeepBass9 said:

Apparently he has left and I have no response from anyone else.

Oh, I haven't had to speak to them in a long time. I haven't installed those relays yet so I don't have experience with them but but can find out from a friend tomorrow if he has 

So I have a response from Microcare. They say the the units are not adjustable and the adjustment is set at 0.03V per degree (which was not disclosed originally). They are also of the opinion that the 0.005 voltage adjustment required is so minimal it is not worth bothering about.

So now I have a conumdrum. On the plus side the temperature and voltage is being measured accurately, and both my MPPTS are reading the same voltage and so go to float at the same time which is good. What is bad is that the voltage is being adjusted by 6x too much.  

My batteries are in a room so now they are around 25 degrees, in winter I suppose they will go down to about 15 deg. (lots of thermal mass in a 50kg battery), so potentially the charging volatges will be adjusted downward by 0.3V

So should I leave the units connected, or disconnect and not use them?

Edited March 26, 20196 yr by DeepBass9

31 minutes ago, DeepBass9 said:

So should I leave the units connected, or disconnect and not use them?

DB, my gut tells me I would not be bothered too much about it. The problems really come in at over 40 and close to freezing from what I have cleaned over time.

Which option, or either?

56 minutes ago, DeepBass9 said:

Which option, or either?

The temps you mention are acceptable to most standards. Leave them in place as you like the data.

On 2019/03/19 at 1:32 PM, DeepBass9 said:

measure voltage much better than the MPPT by itself

I have noticed a slight battery voltage difference between my two Microcare MPPT’s, connected to the same battery bank. The one will almost always be 0.1 Volts higher than the other. At times the voltage is the same for a few seconds, so I assume the difference is closer to 0.09v or so... 

On 2019/03/26 at 10:26 AM, DeepBass9 said:

MPPTS are reading the same voltage and so go to float at the same time

Did you find that since fitting these relays, the voltage is now the same on both MPPT’s? 

I have sent my controllers back to Microcare for software upgrades, but still there is a voltage difference. I even tried to lengthen the cable between the controller and battery (of the higher voltage one) in the hopes of loosing 0.1v through longer cables, but no change. 

Im trying to not let it bother me, but there is always that 0.1v difference in the back of my mind. 🤪

The voltage measuring is better than before as the cables are identical in length. Previously when the voltage was measured at the mppt, the cable lengths were different. They are still not precisely identical though.