The mppt battery connections are connected to the main positive busbar and are connected to their own separate solar system and are reading the same battery voltage,
the two 100/50 units do go to absorption voltage and float,
the 100/30 and the 75/15 don’t, they stay in bulk all day and never go into absorption or float,
I’ve had the whole system networked together with no change, all units are set to the default lithium battery profile except for the adsorption time changed to 30mins,
can anyone advise on what to look for or am I looking for something that doesn’t exist,
this system is on our catamaran which we do have the multiplus on 24/7 running a small 240v freezer, a 74ltr 12/240v day fridge which are the main 24/7 loads.
guystewart
(Guy Stewart (Victron Community Manager))
2
Yes sorry, the two 100/50 units are Smartsolar, the 100/30 and the 75/15 units are Bluesolar using the Bluetooth dongle, networking through Ve.smart networking. The whole system is less than 6weeks old except for the 100/30 and the 75/15 which I’ve had for a while.
Cheers
guystewart
(Guy Stewart (Victron Community Manager))
4
Unfortunately Synchronised charging on VE.Smart Networking is only available on SmartSolar Chargers.
It is not possible to enable synchronised charging when using a VE.Direct Bluetooth Smart dongle.
1 Like
guystewart
(Guy Stewart (Victron Community Manager))
5
As to why they don’t reach Absorption themselves autonomously, we need more information.
Can you please post some screenshots of the history in VictronConnect from all the MPPTS on days when you know your batteries have been fully charged by the Sun.
Ok thanks Guy, so I can only network the two 100/50 units, so the BMV700 (which is using a dongle) along with the 100/20 and the 75/15? The multiplus has a Ve.Smart dongle connected to it, does that mean that only the 100/50’s and the Multiplus can be networked? I will post aome screen shots.
Hi Guy, our system has just made 100% charged according to the bmv700, I’ve attached four screen shots of the mppt controllers, all the shots are from today 05/10/2024, the first two shots are of the 100/50 mppts, the third is of the 100/30 and the fourth is of the 75/15, as mentioned the 100/30 and the 75/15 dont reach absorption, they get close if I extend the absorption time to max on the 100/50 units.
guystewart
(Guy Stewart (Victron Community Manager))
8
It looks like there is some wiring issue.
The 400W Davit panel is seeing a maximum battery voltage of 14.2V, while Cabin Top only sees a maximum of 13.84V, There is a chance that this is caused by a voltage rise on the 400W davit MPPT side, which means the battery voltage itself isn’t reaching the target.
Can we see a trends graph of the BMV for a similar cycle to see what the actual voltage at the battery is?
0.4V is quite a significant difference.
The panel voltage on Cabin Top is also very low, the MINIMUM allowable is +5V from battery voltage, and here the PV panel is at 20.27V maximum, while it’s still working, when the differential between the two is this low the power efficiency is not very good.
