Hi 
I’m trying to setup a secondary lithium battery with solar charging in my van. I’ve created a simple schematic of the planned components, does anybody have any suggestions?
1 Like
Hi @rickname ,
The SmartSolar 100-30 does not have a load output terminals.
You could use a SmartSolar 100-20, as this will suit your (36 cell?) 120w solar panel. and has a load output terminals rated to 20a.
1 Like
A 12V panel will never be able to charge a 12V battery using an MPPT. PV voltage has to be Vbat+5V in order to start charging, then it is allowed to drop to Vbat+1V.
Are you sure that Voc is just 12V?
If you stick with a single 120W panel, lets say one with 36V Voc, then a 75/15 would be plenty. With the added bonus that this model actually features a load output
Why a 200A fuse on the battery? The max current that can flow there is 60A, 30A coming from the Orion and 30A coming from the MPPT, so a 70A fuse should be plenty.
Is the smart shunt adding any value besides measuring starter battery voltage? If you are using a battery with integrated BMS then most of them feature bluetooth, so you can check the SOC, voltage, temp and whatnot directly on the battery. So the shunt is in this case redundant
Thanks Klim, I had not noticed. I initially selected the 100/30 because it was a similar price to the 100/20. Think I’ll switch that out to the 100/20
Ah yes I was wrong on the open circuit voltage, it’s around 20V so that should be fine. And yea good suggestion on the smart solar version, i initially choose the 100/30 because it was a similar price, but i can imagine my load going up above 10A even… will swap to 100/15 or 75/15 instead.
The BMS in the current LiO battery I have doesn’t have Bluetooth monitoring, but I can see others do. Perhaps I can just go with one of those.
I get what you are saying with the 200A fuse, I was sizing based on the battery max load out rather than sizing for the actual loads.
Thanks for the suggestions!!