question

ozonna avatar image
ozonna asked

Multiplus 2 gx 48v and bluesolar mppt + bluesolar pwm

Hello there.

i am new on the forum and new at installing solar energy !

i am planing to install a multiplus gx 48v/5000 in an off grid environment with a diy lifepo4 battery in 48v.
i a have 2 brand new 425w solar panels ( 50,2 Voc / 10,08A max current) i plan to install with a mppt 100/20 module.

this seems to be a good solution for me, to be able to add maybe some more panels and new mppt in the future. I also keep the possibility to add a generator in case of necesity.

my question is the following :

i have 2 older panels (37v, 44,6 Voc, 4,86 A max current) that i would like to add on it. can i use a bluesolar pwm 48v / 10 A with the installation ?

how should i connect it ? Together with the mppt on the battery?

thank you for your help !

Multiplus-IIMPPT ControllersBlueSolar PWM
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

2 Answers
Duivert NL avatar image
Duivert NL answered ·

i think you can get it to work if it supports lifepo but the bluesolar 48/10 can not communicate with the system, so the GX device or the battery BMS can not control its charging, better of with a new VE direct mppt

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

ozonna avatar image
ozonna answered ·

thank you for your help.

if i understand well, you mean i should use 2 mppt ?

I don't know if it is right, but I read that the mppt 100/20 will not work with only 37V input (2 solar panels 18,5V in series). It won't charge 48V battery.

Is this true ?

and is it important that the GX device communicate with the battery BMS ? if I insert the battery specs in the GX device isn't it enough to know its state of charge ?

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Duivert NL avatar image Duivert NL commented ·
Ah no that wont work, i thought your specs were for each panel, not already in series, you cant use those then


the mppt needs 5v minimum above battery charged voltage level… thats not 48v + 5v, you need the charging specs of your batterys for that


Are the specs you noted for the new panels also in series or single panel specs?

You either need to connect the bms to the cerbo bms can bus (if it is supported)

Or you will need a shunt in between connect to the cerbo for measurement amd control

0 Likes 0 ·