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richos avatar image
richos asked

Which MPPT Charge controller would you recommend for a flexible panel?

Hi I’m new to all this solar stuff I have a 300 watt flexible monocrystalline solar panel Max 18volt, max power 16.6A & open circuit 22.4volt and want to purchase a Victron MPPT charge controller to go with this to charge 3 batteries on my boat 1x 160amp hr & 2 x 97 amp hr batteries what charge controller would you recommend. Any help appreciated. Thanks Richo

MPPT SmartSolar
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5 Answers
marc-de-montreal avatar image
marc-de-montreal answered ·

hi, 300w divided by 12v give 25amp to the battery bank.. if you don’t think to expend your solar, a 30-35amp controller is enough for your system!

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richos avatar image
richos answered ·

Hi Marc-de-montreal thanks for your quick reply so I don't really have any room to expand solar panels so will probably just go with this 300watt panel. So are you saying a Victron SmartSolar MPPT 100/30 12 volts would be ok for the batteries I have? Thanks Rico

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marc-de-montreal avatar image
marc-de-montreal answered ·

yes Rico, go for the 100/30 model and have fun with it!!

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richos avatar image richos commented ·

Cheers thanks marc I will.

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dazey77 avatar image
dazey77 answered ·

A 100/20 smartsolar would also be a decent choice. Realistically the controller will rarely ever limit the output. You also get a load output and save some money but there isn't that much in it.

Got to say I really don't get how your battery bank is connected.

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marc-de-montreal avatar image marc-de-montreal commented ·

with around 350ah (near 4000wh) of battery bank, and 300w PV input, you think that saving few pennies with a 100/20 is a good idea? ..each watt in this configuration is to take with enjoy!!

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dazey77 avatar image dazey77 marc-de-montreal commented ·

Wow, thats aggressive. Having a bad day are we?

I stand by my comment, I don't say its a better option than your suggestion but I really don't think there is much in it in terms of what you will actually get out of the system.

The days you really want extra power are not the sunny days but the overcast ones.

Peace

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marc-de-montreal avatar image marc-de-montreal dazey77 commented ·

sorry, you look sensitive.. don’t worry!! :)

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richos avatar image richos commented ·

They are not connected to anything at the moment I’m still new to all of this hence I’m trying to get some assistance. As you know I have 3 batteries One is for my house supply (160 Ah) and the other two (97Ah) are my start batteries. So I’m wanting to keep all of these topped up with Solar. Hope that makes sense. Appreciate all the help I can get.

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dazey77 avatar image dazey77 richos commented ·

OK, that makes sense but I am afraid that what you ask is not simple. Victron don't really have an offering for managing to charge house and starter batteries from one panel/controller. My suggestion would be that you add a second small panel and simple controller for the start battery.

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richos avatar image richos dazey77 commented ·

Hi dazey77, thanks for that I thought you could link all batteries together and trickle charge all from the one panel. You’re saying that’s not possible?

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dazey77 avatar image dazey77 richos commented ·

Correct, thats not possible. If you join them all together then you they won't get drained evenly and you will be able to drain the starter battery from the leisure side, which defeats the aim.

Normally you would join the two through a intelligent switch like the Cyrix or a DC-DC converter to allow the engine to charge the leisure battery side when its running, but these are only one way.

There is a good victron wiring guide (free ebook) called wiring unlimited that discusses a lot of the issues with joining batteries.

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richos avatar image richos dazey77 commented ·

Cheers I’ll have a look at the ebook guide. Thanks!

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klim8skeptic avatar image klim8skeptic ♦ richos commented ·

A Bluesolar DUO will charge your 2 separate battery banks.

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richos avatar image richos klim8skeptic ♦ commented ·

Thanks for that I will have a look at the Duo. Cheers!

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bbrouwer avatar image
bbrouwer answered ·

Which flexible panel do you have. I also want to install one on my boat. Do you have datasheet?

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richos avatar image richos commented ·
  • Hi bbrouwer I’ve got the OkSolar 300watt Flexible Solar Panel. Have no idea what they are like haven’t fitted yet just trying to get everything together. Reviews were good so giving them a go.

https://oksolar.com.au/products/300w-flexible-solar-panel-kit-t3

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