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sylvana avatar image
sylvana asked

Changing mppt 70/15 to lithium setting

Hello, we have fitted lithium batteries 2x220 ah 24volt . We are using a multiplus 3000 charger inverter and have 2x100 watt solars coming to a mppt 70/15 blue solar charger. How can we manually change the 70/15 over to the lithium setting. Cannot use Victron connect on it. Many thanks.

MPPT SmartSolar
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matt1309 avatar image matt1309 commented ·
I know some MPPTs have dip switches that allow you to alter the battery charging profile without using Victron Connect however I had a quick scan in the manual for 70/15 and couldn't find reference to the dip switches.

Is there a reason why Victron Connect doesn't work?

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djsmiley avatar image djsmiley matt1309 commented ·

Blue solar has no bluetooth, only smartsolar. So unless you have the BT dongle or VEdirect cable you can't use Victronconnect

Use the small dial to set (if not overriden by the settings). Best is to get a VE Dongle or VEDirect cable, also allows you to update the unit. Either buy or find a dealer near you who can do that for you (since it's just a change which needs to be done once)

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sylvana avatar image sylvana matt1309 commented ·
Thank you for your reply.
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1 Answer
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klim8skeptic answered ·

@Sylvana your 70-15 mppt only has 1 charge profile that suits lead batteries.

That said, the 28.8v bulk/absorption voltage is probably ok for most lithium.

Also, while the float voltage is a little high at 27.6v, there is only limited sun hours that the mppt can hold that voltage. (if ever given your small array)

The only major problem comes in with mppt temperature compensation. At temps below 25c, the mppt will move the charge voltages up. Likewise at higher than 25c temps, the mpptwill lower the move the charge voltages down.


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sylvana avatar image sylvana commented ·
Thanks for your help, I think we now have it sussed.
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