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Multi string MPPT / Optimiser?

Doug42

New Member
Joined
Oct 5, 2023
Messages
21
Location
Cambridge
Hello,

My googlefu has come up empty handed

Has anyone come across multi string MPPT controllers? not inverters with multiple MPPTs but a straight forward PV -> battery charge controller? fairly small scale say 1 to 2 panels per string

It is just multiple times now the only solution I have found for small Van setups, static highly variable shade conditions etc is to have multiple charge controllers which seems highly inefficient both space and cost wise

I have come across multi input micro inverters such as:

but AC out really isn't what you want in small setups (or most the time frankly)

Anyone come across a product that lets you connect up about 4 dissimilar panels without going the equally pricey and cumbersome optimiser route?
 
I have a Victron Smart Solar 75/15 running off a single 200W panel in my van, I use it to keep the starter battery topped up.
For the leisure battery I have a Redarc BCDC1240D to charge a Victron 100Ah Lithium Superpack either from the van smart alternator or the same 200W solar panel on the roof (I have a changeover arrangement so I can select which charger gets the solar input, never both at the same time)
I'm just in the process of installing home solar with battery and have gone for Victron MPPT's (3x 250/60's) and their Multiplus II inverter. I rate Victron very highly.
 
Thanks for the reply but that's not really the question although that is a great example of it! 3 seperate MPPT controllers can not be an efficient way of doing things. each with their own enclosure, communications, bluetooth, LEDs, MCUs, internal power rails etc... I know you can solve this problem by just trowing a pile of chargers at it (just did an awkward shed roof for a friend with 3 MPPTs, my van has two chargers, one for the roof and one for the side panel. same story in other installs)

Here is my boy:
1738617657330.jpeg


on a side note:
personally I have found victron quite overprice. their electronics is maybe average or a hair above but their prices are top shelf premium, their marketing does all the hard work. As far as I can tell they are a peace of mind big brand if you don't want to shop around too much or take the time to understand the alternatives which I am not trivialising, that can be a valuable thing, especially as there are a lot of people new to electronics getting involved in vans and solar, I wouldn't recommend everyone goes off the beaten path. I have just never speced out a system and by the time I have finished my research, victron has actually been the best option. Im not telling you to avoid them, their stuff is decent, works and they have a sort of hit and miss support system. I just hear them worshiped a little too often and there is some really good gear out there now!
 
AFAIK Not to the miniaturization level of that Hoymiles 4:1 you found. IMO not going to happen because the target market for your parameters is tiny.

You can maybe look at MPPT for micromobility, like charging scooters from one panel. Probably not the most robust.
 
thanks for your 2 cents. Well no one is pointing me to some obvious product that I missed which is a result in its self

To the scale I would say the whole multi panel RV market and small remote buildings like garden offices and workshops which often have very particular shading. solar in the garden is quite a popular option as installing underground cables is expensive and requires large amounts of labour, ground damage (and an officially registered electrician) etc. I should know, here is an image of an none trivial hole I dug a few months back:
2024-10-25-16-21-40-725.jpg
And if I am being honest I was probably still 10-20cm shy of regulation depth at only ~400mm but regs wording is fluffy it was going under a slabbed path so meh

Point being, the problem of 2-5 disimilar/shaded panels seems like a common one. and yes, it is solvable with DC optimisers or just multiple MPPTs but this is inefficient and I am surprised there is not a one box solution if for no other reason than install/user simplicity
 
Yes, I wish there was a solid DC optimizer that is not Tigo and not SolarEdge, because they both suck in different ways. But it doesn't exist on the market, and presumably that is due to a correct reading of Total Addressable Market 🤷. The micromobility MPPT or hacked SolarEdge optimizers are not code compliant to use in the US.

So until I see otherwise, all my system thinking for small arrays on houses is with AC coupled microinverters, which unfortunately adds cost because of the extra complexity of the hybrid it needs to be combined with. But it exists and at the robustness of 100K - 1Ms of installations, while the other options don't.

Shading tanks production so much (Let's just call it 50% best case if on half-cut, I know it's not that simple and shingled can sometimes do better) that a consistently part shaded out building with only 4-5 panels will likely have a hell of a time powering itself beyond 1-2kWh of daily load.
 

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