Floating lithium batteries

I have 3 LiPO4 batteries being fed from a 100/30 Smart Solar and a Multipass Compact 12/1600 hanging off the batteries.

Both the Smart Solar and The Multipass are configured for Lithium LiFPO4.

The Smart solar will tell me I am in Float mode , but if I Connect shore power to the multpass it immediate goes to bulk charge for almost an hour sending 40 amps (Max Configured) to the batteries before it goes to absorption (around 5 amps) and then float.

Why is this so?

Is the Smart solar under charging or the multiphases over charging?

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Alexandra ♦ commented · Nov 02, 2020 at 11:50 AM

@David Keating

Maybe check the battery settings on the mppt vs what is set on the inverter.

0 ·

David Keating Alexandra ♦ commented · Nov 04, 2020 at 07:55 AM

The MPPT Charger is set to Position 7 (Lithium LiFePo4 14.2 absorption 13.5 float.

Multipass set to Lithium and same voltages.

I have had the setup for about 18 months and it seems to work ok but this spurt of bulk charge when i first connect shore power really confuses me.

0 ·

oceanwolfe David Keating commented · Nov 14, 2020 at 02:12 AM

Are both units sensing the battery voltage at the same location? Maybe one is seeing a different voltage than the other is.

0 ·

hummingbear commented · Nov 16, 2020 at 04:50 PM

Yup, this really bothers me as well that the victron inverter/chargers don't communicate with victron charge controllers. In theory it will go into bulk mode only for a short period and then will go back into float, but this can cause overcharging IMO.

@mvader (Victron Energy) is there anyway for a Multiplus Inverter/Charger to recognize when a battery is in float from another Victron device (i.e. charge controller) and not automatically start bulk charging when shore power is provided?

0 ·