Sol-ark 12k canbus necessary?

[scott harris]

I have a Sol-Ark 12k and a DIY 48v 280AH battery with an overkill bms. Overkill does not have a canbus port. Is canbus really necessary. Won't the solark control charge/discharge via SOC

 

[Hedges]

How would SolArk know SoC?

BMS probably tracks SoC by amp hours, and resets based on voltage.

Is SolArk told how many amp-hours? Does it provide similar SoC tracking? If not, all it would have is voltage.

Does SolArk have an open-loop lithium mode? My Sunny Island, we either have it talk to lithium BMS, or else tell it the battery is VRLA, and tweek voltages to correspond to lithium. It does estimate SoC for lead-acid.

 

[scott harris]

I have a Sol-Ark 12k and a DIY 48v 280AH battery with an overkill bms. Overkill does not have a canbus port. Is canbus really necessary. Won't the solark control charge/discharge via SOC

Oops. I made a mistake. Not SOC but pack voltage level.

 

[scott harris]

According to Sol-Ark the way it is supposed to work is that the bms sends signals via canbus sa the battery nears the top and this causes the solark to reduce the charging level until eventually it is zero.

But solark already knows the pack voltage and has a maximum voltage setting for the battery. So in the case where a bms does not have canbus, wouldn't the solark just simply stop charging when the battery reaches pack maximum voltage?

Has anyone had success connecting a battery to solark without a canbus link?

 

[Hedges]

Sure, it should be able to charge and cut off discharge based on voltage.
I don't know the particulars of configuring SolArk, if that would be open-loop lithium, or something user defined.
For Sunny Island, it looked like a nominal voltage different from 48V (24 cell lead-acid) was needed to get target voltages at the top and bottom knees of LiFePO4.

If it does estimate SoC based on current x time, then it may be able to control discretionary loads in a nicer way.

Communication may work better, so BMS can request reduced charge current so balancing can occur. Otherwise, if too far out of balance, all it can do is unceremoniously disconnect.

You may need to set reduced max voltage to get that to work. Depends on how much imbalance. Having enough PV to fully recharge often could keep battery in better balance. Of course quality of cells makes a difference too.

Have to see if anyone with first-hand experience can report.

 

[Quattrohead]

You can set it to use comms or manual settings with use voltage or calculated percentage of charge.

 

[Nobodybusiness]

I have a Sol-Ark 12k and a DIY 48v 280AH battery with an overkill bms. Overkill does not have a canbus port. Is canbus really necessary. Won't the solark control charge/discharge via SOC

If you are not running closed loop BMS change your control to Batt-V.

 

[Llaves]

The 12K can operate in open-loop voltage or SoC mode. In open-loop SoC mode, the Sol-Ark uses an internal shunt to integrate the actual power used and calculates that as a percentage of programmed amp-hours of battery capacity. It recalibrates the SoC when the batteries reach 100% SoC based on reaching the absorption point voltage at no power (roughly speaking). My Sol-Ark operates open loop and reports SoC within a couple of percent of what the BMS reports. On the other hand, my system reaches 100% SoC almost daily.

 

[myles]

The 12K can operate in open-loop voltage or SoC mode. In open-loop SoC mode, the Sol-Ark uses an internal shunt to integrate the actual power used and calculates that as a percentage of programmed amp-hours of battery capacity. It recalibrates the SoC when the batteries reach 100% SoC based on reaching the absorption point voltage at no power (roughly speaking). My Sol-Ark operates open loop and reports SoC within a couple of percent of what the BMS reports. On the other hand, my system reaches 100% SoC almost daily.

I have experienced this with my 15k. 100% soc almost immediately after charging starts, but after full charge I find the SOC in powerview is fairly close to the bms SOC within 3 ish percent after you leave it sit and stop messing with charging settings for a week or so. It also does a fairly accurate job of calculating total AH in the pack after you do a full charge discharge cycle on the batteries.