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lagom avatar image
lagom asked

Which charge controller to buy for 11.1V Li-Ion 3S2P battery packs?

Which charge controller to buy for 11.1V (nominal) Li-Ion 3S2P battery packs? Background is I want to hand out LED lights to food truck festival guests, and have a well working battery pack/LED set-up working. I would like to go completely off-grid during the summer months and no longer charge from the mains during the day, but use PV modules for the task instead.

Which victron solar charge controller would be best suited for this type of battery cell chemistry and pack configuration?

Thanks in advance for some advice!

Lithium Battery
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lagom avatar image lagom commented ·

I tried out that demo app, but what does it mean? Shall I buy the SmartSolar 75/10 for our type of battery packs?

Maybe a company rep could chip in about what to buy?

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Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

You can use the demo library of VictronConnect to check if you can set the charging parameters as you need. All MPPTs have the same parameters.

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lagom avatar image lagom commented ·

I set the below demo settings in the demo app. Does that tell me that the MPPT 75/10 is the correct choice for my battery packs?

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lagom answered ·

Sorry, I don't quite understand. VictronConnect appears to be an app to monitor one's devices.

My question was about which device to buy for my use case. I don't own a Victron product yet.

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·

VictronConnect is an app to monitor and setup most of the Victron products.

It includes a demo library to simulate all the products and can be used to check if a product supports the things you need before you buy it.

Just install it to you smartphone, tablet or PC/Laptop/Mac and test it.

https://www.victronenergy.com/panel-systems-remote-monitoring/victronconnect

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lagom avatar image lagom Matthias Lange - DE ♦ commented ·

Ok, I found the app and demo mode, and for the battery packs I bought (Rechargeable Lithium-Ion (LiNiMnCoO2) 3S2P pack, capacity 15,000mAh; 12,6V max. charge; 11,1V nominal; 9,3V cut-off from protection circuit) I entered the following: Battery voltage 12V, Maximum charge 2A, Absorption voltage 12,6V; Float voltage 12,3V; Equalisation voltage I left at 12V, because automatic equalisation is disabled (the battery has a built-in BMS).

So, what can I learn from this? Shall I buy an MPPT 75/10?

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kevgermany avatar image
kevgermany answered ·

Couple of things.

The MPPT controller should always have a battery connected. If this isn't the case, you should disconnect the panels, then disconnect the battery.

You are intending to set fixed charge current, possibly across multiple batteries, possibly across multiple cells. You may get uneven /overcharging issues.


Might seem more complicated, but consider setting up as follows

Install reasonable size 12V battery

Set up panels/MPPT to charge this

Use standard 12V input LiPo chargers from this battery to charge the handout batteries. (number depending on how many batteries you want to charge at the same time)

Then you simply plug the handouts in/out as needed.



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lagom avatar image lagom commented ·
Cheers, the solar module is disconnected before the battery can be taken out of its (modified for that circuit breaking function) charging cradle, so we got that covered. Each researcher has one unit (solar module, solar battery charger, product with battery), so there won't be multiple batteries attached to each solar charger unit.


It's actually quite simple, think of a DeWALT power tool with detachable 3S2P battery plus charger, only not charged from the mains (off-grid situations), but from solar.

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kevgermany answered ·

Then you are back to the original suggestions from Matthias. But you have to make sure the panels cannot deliver more current than the battery packs can take. Victron controllers are built for bigger systems, not ideal here


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