question

mstoeger avatar image

parallel MPPT charger, but not charging simultaneous

Hi all,

I've expanded my system with one additional Charger and new Panels, loading the same batteriebank.(24V, 660Ah OPzS),OffGrid

Old one: BlueSolar MPPT 150/70 ve.can, Firmware 2.05, charging from 6 Panels/260W
Additional, new one. : Smartsolar 150/70 ve.can rev2, Firmware 3.02, charging from 6 Panels/280W

Both chargers are connected with ve.can to a GX control. I can see them also in VRM-Portal. Both chargers with same default settings (no2). They are switching simultaneosly from one mode to another. But the 6 year old bluesolar charger ist only charging as expected, when I deactivate loading of the new one. Why do they not charge together? Maybe the two chargers are not compatible?

I've built up the system in southern Greece by my own in lack of a victron vendor near Kalamata. Now I'm lost.

Thank's for your help

Michael



chargerparallel
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4 Answers
klim8skeptic avatar image
klim8skeptic answered ·

Depending on what other Victron components you have, DVCC might be useful for MPPT synchronization.


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mstoeger avatar image
mstoeger answered ·

...thanks for quick response...

I tested DVCC without success, getting error #48, maybe because the Mutiplus is running with firmware 158.

Anyway, in another feed somebody said, the older MPPT VE.can, the one with screens, aren't able to be controlled by DVCC.

I'm a bit afraid to update my Multiplus, don't having a failover. Not knowing if this really will solve the MPPT problems, it seems to be a high risk...

any other ideas?

Thank you

Michael




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mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hi, are you 100% sure one of them is not properly converting/producing when both are switched on?


can also be that simply there is no more demand for amps: the battery (or whatever load you have) simply doesnt accept more amps; and as a result the mppts are at or close to their voltage setpoint (either the absorption or float setpoint).


to check this, the vrm graph is usually the best place: look at output voltage and current for the two mppts.


or alternatively: increase the load. And see that one of them “picks it up”.


hope that helps! Matthijs

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mstoeger avatar image
mstoeger answered ·

Hi, thanks for this tip.

I tried to stress the system this morning with a 2000w Hairdryer and really the old charger began to load with less than 200w, whereas the new one gave more than 600w. With the same test on midday with better conditions of the batteries the old charger didn't load.

I changed the PV-Arrays giving the old charger the new panels. Same result. But I found a difference:

Permanently MPPT of the old one is about 15V higher. Even at night PV-Voltage is 15Volt. Maybe this is the problem?


screenshot-mppt.jpg




screenshot-mppt.jpg (163.0 KiB)
1 comment
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Hi @m.stoeger@web.de


The MPPT measuring that voltage at night is not good indeed, it should be replaced.

I'll send you an email.