Need to charge a 48v LFP battery from a single 450W solar panel. How is this done? Non-Victron options only?
Victronās MPPT Calculator will suggest best Victron charge controller based on your location and your panelās parametersā¦
This depends on the VOC of the single panel, However, it is unlikely to have a high enough VOC to fully charge a 48V Lithium battery, or to drive either a PWM or MPPT controller for this purpose.
If you post the battery voltages and the VOC data from the panel, further advice can be given.
No, but I wish that was true. There is an āAsian 450W Solar Panelā option in the calculator. When I select that and select 1 panel / 1 strong for charging 48v LFP, the Victron MPPT Calculator chokes. The reason is due to the engineering decision to save 2 MOSFETs by making MPPT controllers that are buck-only. Certainly not a premium product.
Choose ācustomā and enter your actual panel specs.
I can count the number of reputable companies making boost solar controllers on one hand with fingers left over, so that Victron MPPTs are buck-only has nothing to do with āpremiumā or not.
You can select ācustom panelā and provide your panels parameters. But there only a few high voltage panels on the market like the Maxxeon 3 with around 70Voc.
I just wanted to use Victron for MPPT but lack of flexibility sent me to Shenzhen. Again. Second time in 3 months. The previous remove-and-replace came when I went from 12v to 48v, thats when I lost my Orion XS - I would have replaced it with a 48v DC-DC charger from Victron but that effectively does not exist, unless you want to say that charging at 8 amps from a 200A alternator makes sense. Its ok though, Shenzhen came to the rescue twice in 3 months.
Perhaps you could share a bit about what the setup is for - eg a boat, truck, camper van, tiny cabin in the woods?
Are you looking for 120V or 230VAC ?
Regarding the Orion, just noting that 8A at 48V is the output, so thatās drawing about 36A from the 200A (peak, not continuous) alternator assuming 13.8V.
Kinda like the 7.5A youāll get from charging a 48V nominal battery from a 450W solar panel with the Shenzhen solution.
Anyway, we all know its frustrating when the perfect solution isnt available from a vendor that actually supports it after the sale.
The application is an F150 with a Leer cap on the bed and a 450W solar panel that just barely fits on the truck cap. Thereās absolutely no way that I will waste space by splitting it into multiple panels just to satisfy the requirement of a buck-only MPPT controller. A cheap 1200W MPPT controller with boost is $75. Thereās no instrumentation other than a funny little 2x2cm LCD display that wonāt ever be visible because its mounted out of sight. The battery is 16S 304Ah EVE LF304 cells in an enclosure designed for 16 large LFP cells in series. Its a small 48v system designed to provide 48v to a Zero Breeze Wave 3 air conditioner and a 30A 48v to 12v buck converter to power 12v devices. Iām not suggesting that any large Victron MPPT controller should have the 2 extra MOSFETs to enable boost, however, I have the smallest Victron MPPT controller that supports 48v, a 100|20. That specific device should support boost due to the most likely use cases, which will include single panel designs.
Sounds like itās going to be a nice setup especially on hot days. 
Does the EVE enclosure have a built-in battery management system (BMS) to prevent overcharge/over-discharge ?
I agree with you that boost is going to be a more common use case; but the problem is its a lot of boost needed. With a 450W panel, say the max power point is around 40V, 12A, thatās a lot of boost, so you might see 8A to charge the battery.
The Zero Breeze is going to draw 5280BTU/h * 0.293 = 1547 W at full tilt. I canāt figure out the ZB site says 600W needed - something doesnt make sense about the math. Maybe its duty cycle eg on only 20 minutes every hr? I donāt know. The cable they sell is touch undersized for that.
Iām a bit stumped on how to help - e.g. without forking out big $$$ and not changing the panel for 2 200W+ units.
Long story short, Victron does not manufacture boost solar controllers, so now that youāve redesigned your system in such a way that it requires a boost solar controller, youāll need a different brand.
The Zero Breeze A/C uses around 500W when set to maximum cooling.
Certainly its Victronās choice whether they want to compete for the boost MPPT market thats apparently emerging as 48v becomes dominant. My new 450W panel is showing up to 389W flowing into the battery using a no-name boost MPPT controller that cost $75 on Amazon. Right now I see that coming in via my 16S JK-BMS which is connected via RS-485. I will put a couple of Victron shunts in line with the boost MPPT charger and DC-DC charger to justify continued use of VRM, otherwise Iād have to convert my monitoring setup to NodeRed+HomeAssistant.
I doubt that low-end of the market is all that attractive or profitable. Best left to the Chinese.
If $75 is the budget it is unlikely the rest of the portfolio would be all that attractive, trying to chase that market wouldnāt make a great deal of sense.
Not something we see requested all that often here.
As a Product Manager, I know it is easier to let marketshare erode to the competition. Note that the Victron 100|20 is also $75. Disposable no-name China products are the quick fix for me at this point and I donāt mind using Victron Smartshunts for monitoring. Since the 100|20 MPPT controller is new, its likely a v1.0 product. Really hoping the PM for MPPT controllers at Victron is not close to retirement so that the v2 feature list matches the most likely use cases.
IIRC, its about 6-7 years old, so not that new. You raise a good point about product management needing to respond to the competition - itās not easy to tell whether the 1 big panel boost solution is going to be a big enough market opportunity; especially when there are so many other needs competing for scarce development and engineering resources. e.g. EV, High Voltage, big systems that are beckoning for attention. That said, Victron is pretty innovative and hopefully the bright future ahead will let them address needs like yours.
Partially trueā¦
MPPT RS range are all boost MPPT controllers inside.
Multi RS Solarā¦ the same.
So, his statement that additional, not so expensive, FETs could transform the standalone MPPTs in a more versatile buck-boost MPPTs, is pertinent.
Imagine the advantage, especially in variable light conditions, (RV, boats, etc, where space is a premium), when the MPPT will not stop when the panel voltage will drop below battery voltage.
I doubt that Victron would sacrifice their MPPTs efficiency numbers to chase a tiny fraction of a market. As has been said, leave that to companies already doing boost MPPTs. Iād also suggest that many of the boost MPPT manufacturers are lying about their claimed efficiency. Of the non-Victron MPPTs iāve tested, i havenāt seen a single one reach the efficiency numbers they quote. Its obvious when you see how hot they get that a considerable percentage of the energy is going into heat, not going into the battery.
For the OP: there are plenty of panels available where all/most of the cells are in series, we stock a 460w panel that is ~62v Voc, perfect for a single panel on a 100/20 with a 48v battery.
For a panel/mppt pairing where the panel voltage is nominally above Vbat (the normal situation), reflecting on the situation at first/last light that Alex mentioned, I donāt think that the power available in the part of the curve where Vp is below Vbat is worth chasing - its so small that in most cases it will be below the running cost of the MPPT. This is exactly why Victron mppts have an āoff (insufficient PV power)ā mode: the cost of running the tracking and circuitry would net a negative amount of energy.
For a panel/mppt pairing where the panel is ALWAYS below Vbat (ie a boost MPPT): A few cents for a pair of FETs sounds like nothing, but you would be trading off the efficiency loss in the rest of the curve (ie 99.9% of installations), plus heating issues (much higher currents on the PV side of the board). It seems to me that OP has a simplistic understanding of the MPPTās design.
So the bottom line is that the tradeoffs mean that the most logical market scenario is where you have a normal buck MPPT for 99% of cases, and a specific boost MPPT for the edge cases. Horses for courses.
Also sound points @RoarPowerNZ !
How do you figure? Minimum PV start up voltage is 120vDC to charge a 48vNom battery. Thatās not boost.