# question

## BlueSolar MPPT - Batterylife algorithm thresholds

Hello,

We're using BlueSolar MPPT 75/15 for solar street light application. The LED source is connected directly to the load output of the charger.

I know, that the Batterylife algorithm is changing the load disconnect/connect voltage thresholds, according to how the battery was charged. But what are the actual thresholds for the 12V system, what is the absolute low/high disconnect/connect voltage and what is the daily increment, if the battery was not charged again?

Knowing this would help a lot configuring the light, taking into account the voltage drop in the cables, and also solving some issues with cases where light doesn't switch ON at all.

Many thanks and kind regards,

Peter

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Martijn Coster (Victron Energy Staff) answered ·

Hi @PeroMB,

Below the requested information:

The batterylife operating range is:
switch on voltage range: 13.1V .. 14.2V
switch off voltage range: 10.8V .. 13.2V
The daily increments are: 0.2V

best regards
Martijn Coster - Victron Energy

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·

Hi @Martijn Coster (Victron Energy Staff), does this also apply for the MPPT 100/20?

If I understand correctly: 10.8V is absolute minimum (almost zero).
After a day of charge, the bottom limit will be +0.2 = 11.0 V?

And so on?

0 Likes 0 ·
Rob Tuitert ·

is there any way to avoid to go so low on the switch of?

10.8V is a really low point, then the life of the battery could be very short.

Thanks

0 Likes 0 ·
ivanmmm ·

@IvanMmM There is a really easy way to avoid going so low. Use the Victron Connect app and connect to the MPPT. Then in the configuration menu you can set a user defined algorithm for the load output. Het you can set you own voltage levels.

Martijn Coster -- Victron Energy

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Martijn Coster (Victron Energy Staff) ♦♦ ·
Does any of the user defined algorithms have the +0.2V functionality? I.e. will setting the lower limit to 11.6 result in a limit of 11.8 the second day if absorption is not reached?
0 Likes 0 ·
johan-anderholm ·
Agreed. I want to use the battery life function, but don’t want to go down to 10.8 and torture my battery just to train the system.
0 Likes 0 ·
gsking ·
Same. See my comment below. 10.8v would apparently wreck the battery which would be ironic for "batterylife"..
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·

Sorry, you can provide the same info for a 48 V TAB PbZ battery?

0 Likes 0 ·

Thank you very much!

Kind regards,

Peter

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Thank for this value,

When a complete recharge occur the switch off voltage return to 10,8 volts ? , Is there a way to change this on app ?

Is it possible to use a VE.Direct TX digital output cable (PWM light dimming cable) ASS030550500 to drive Phoenix or Multiplus inverter with this algorithm ?

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Hello,

The BatteryLife algorithm sounds close to what I need, but I am very alarmed that the algorithm can allow a discharge to < 10% capacity. It would be ironic if "BatteryLife" actually destroyed batteries rather than protected them.

This chart here shows typical SoC levels for a lead acid battery. By Victrons own admission, that algorithm would damage the battery after just a couple of cycles.

Thoughts?

1664395090315.png (34.2 KiB)

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