question

bartholdl avatar image
bartholdl asked

IP22 charger absorption voltage way too high when joining a VE.smart network?

Hello all,


I have a IP22 to charge a bank of Battle Born Lithium batteries. On its own it works great. But when I join it an existing VE.smart network with a MPPT 100/30 and MPPT 100/50 solar charger, plus a BMV-712 battery monitor, it all goes wrong. As soon as I join the network the absorption voltage goes from 14.4V (which is correct) to 16.32V. Oops. That is not good. When I leave the network, all is well again. This test was done with the two MPPT chargers not doing anything (no sun on the solar panels). Anyone have any idea?

Thanks for all your insights!


Here's the weird Absorption voltage of 16.32V

screenshot-20210929-205357.jpg


Joined this VE.Smart network

screenshot-20210929-205420.jpg


Here's when not in the network, all is fine

screenshot-20210929-205434.jpg


Setting I use for the IP22

screenshot-20210929-205450.jpg


screenshot-20210929-205459.jpg


screenshot-20210929-205516.jpg

VE.Smart Networkbluesmart ip22ip22
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3 Answers
Paul B avatar image
Paul B answered ·

The referance voltage that is being used is faulty, on the main referencing device, to use the smart network you should ONLY be connecting to a BMV 712 or a smart shunt device. or the smart battery voltage sense unit.

So make sure the BMV is the master unit you are connecting to


suggest

Delete the existing smart network on all devices

then on the BMV make a new network - and connect the other units to the BMV units smart network

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Leslieanne avatar image
Leslieanne answered ·

Hi Bartholtl,

Relax! Your charger is behaving exactly as expected. The smart network allows the charger to "see" and respond to the actual voltage at the battery (as measured by your BMV). The battery voltage in your screenshot is less than your absorb set point, so the charger increases its own voltage to compensate. So you get faster charging at higher amps - in this case 17amps vs 4 amps without networking.

However, you do have a rather large voltage drop, almost 3v, between the charger and battery. This is more than expected. I see less than 1V drop at 25A in our van system (older IP 67 12/30 charger which sadly does not have networking facility!) You should check your wiring, connections, any fuses or breakers for high resistance.

Cheers, Leslie

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bartholdl avatar image
bartholdl answered ·

Thanks Paul and Leslieanne, good suggestions! It makes sense that the charger compensates for the voltage drop. Yes 3V drop is a lot, but my wiring from the IP22 charger to the batteries is fairly long (although it is 10 gauge). I'll experiment with bringing the IP22 really close to the batteries, that is easy to do. Thanks again!


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