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coin3ip asked

MPPT 100/20-48V or DC/DC converter, to Direct Solar Charge a laptop via car-lighter ?

Hi, I'm using the 100/20-48V MPPT to charge my 48V bike (54.6V 10A). it's working great! I'm starting to source flexible panels to make a portable setup to carry onto the bike when riding :)
the 'prototype' setup looks like that at the moment.. :-)


Also, I'd like to use the same setup to charge my other 12V devices (laptop, phone, light, fan, etc..).
So I decided to use a car lighter... it looks like that.

right now, it doesn't work. But I don't know if it's just a problem with the Gissaral 90W charger with a surface connect port at the end (I tried it on a car and didn't work either. I'm gonna send it back anyway), or if there's something wrong in the setup...

My questions are:

- Is it OK to use this kind of car charger after the MPPT like this? (using the MPPT as a DC/DC converter I guess?) or do I need to use something else than the MPPT ? (and if so, what?)

- Is there a way to safely and quickly change the MPPT setup in the app, for switching between my 48V and 12V presets ?
- Is there hope that the app will work using windows bluetooth ?
- maybe not disconnect between each time I take a look at the app ?
- Basically, are there useful updates to the app coming ? would be great!

Also, suggestion:
"We" (I?) need an outdoor/waterproof version of this MPPT :-)

Thank you very much in advance for your help! :-)

MPPT SmartSolar48v battery
solarsetup02-coin3ip-web-01b.jpg (1.9 MiB)
12vsetupcarlighter-coin3ip-web-01.jpg (1.8 MiB)
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2 Answers
Pieter Boomsma avatar image
Pieter Boomsma answered ·

Hi,

Thats quite some questions. Firstly i need to mention that you should first connect a battery before connecting a solar panel. (also disconnection appears in the reverse order so first disconnect the panel, then the battery).

Now, you cannot simply directly feed a 12v setup without having something buffering the energy. You need a battery on the output of the MPPT in order to get this to work.

I think you should be able to connect the device to a laptop with bluetooth with the Windows version of VictronConnect.

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Justin Cook avatar image Justin Cook ♦♦ commented ·

Hi @Pieter Boomsma (and @Coin3ip), it's worth noting that the Windows BT protocol does not support bluetooth connection to Victron Smart devices. To connect a Windows machine to a Victron device you must use a VE.Direct to USB Interface.

See this thread for more detail: https://community.victronenergy.com/questions/10456/am-i-correct-that-i-cant-use-the-victron-connect-w.html

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coin3ip answered ·

Thanks!

of course I plug the bike's battery first. and so, I always have to disconnect everything between each charge. (the app doesn't like that, and I can keep datas from only two charges, then I have to reset because it doesn't create a new "day")

for my laptop test, I only plugged what's after the MPPT. if it doesn't "see" the laptop's battery via the car lighter, I won't plug the panels, at all. and that's what happened.

So, I'd need a 12V or 24V battery bank as buffer, instead of the car lighter charger direct charge. that's a bit sad and adds weight.. I'd really like to avoid intermediary batteries and only do direct charging of the devices.
You don't think I can feed the car lighter by using a DC/DC converter instead of the MPPT to bring my array down to 12V and the amperage the car lighter "likes" ? it shouldn't be bigger or heavier than carrying a second 100/20 MPPT..

Because, basically, the car lighter charger is a DC/DC converter, right? and I assume it's what blocking the MPPT from detecting the laptop's battery. but if I put just a converter instead, it should feed what's down the line anyway, it doesn't HAVE to detect the battery, right?
So it feed the car charger with the same settings than the laptop's AC charger's DC output (that's apparently supported by the charger specs (90W 5A) ), and the laptop does the charging management itself.... it seems coherent to me, but also, I don't really understand anything I'm doing ahaha ... (I mean, I don't have any background in electricity)

ps: the victron app doesn't work with Windows bluetooth. sadly. you need to use the wired connection to use the app on windows (even though you can see the device and it correctly prompts the PIN and connect. but the app can"t use it (it's specifically written in the instructions manual ^^ )

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Related Resources

MPPT product page

VictronConnect manual

PWM or MPPT

MPPT calculator

MPPT codes

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