question

pontus avatar image
pontus asked

Blue solar mppt 75/15 load cutoff

During my first initial charge/discharge cycle of a brand new 40 Ah LiFeYPO4 I had set load to "User Defined Algorithm1" to a cut off voltage of 10,5V. After leaving the battery with a load of ≈ 0,2A I got back this evening finding the voltage had dropped to 9,78V possibly killing my brand new battery.


What am I missing? Isn't the load settings supposed to cut of all current in the load terminals when voltage drops below cut off value?


I have no jumpers installed but the Blue Tooth dongle using the app to configure the MPPT.


Further more, toggling between always on/off does not have any effect. Load stays on all the time.

MPPT ControllersESS
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

3 Answers
ejrossouw avatar image
ejrossouw answered ·

Hi @pontus

What steps have you taken to try and resolve a possible issue?

  1. Is the firmware installed the latest?
  2. Have you reset the device to factory defaults and tested it again?
  3. Have you disconnected the Bluesolar from everything for a couple of minutes and tried again? (IMPORTANT - Reconnect loads (turned off) first, then battery and last solar
  4. What is the voltage of the battery measured at it's terminals? The same as in the app?

The good news is that Lithium battery technology is a bit more robust than LA. Think of how many times a mobile phone battery may have been completely depleted and then recovered again.

Let us know after you confirmed the above was done and did not resolve the issue.

Regards

Etienne



1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

lucky avatar image lucky commented ·
Using mppt 75/10, it cuts out load when there is a firmware update, don't want that.. any suggestions??
0 Likes 0 ·
pontus avatar image
pontus answered ·

Thanks @ejrossouw your quick reply. I will try to provide some more details about my set-up, which is currently in a lab.

  • 40 Ah LiFeYPO4 12 V battery (GWL, matched cells, no BMS)
  • BMV-700 ( firmware : 3.10 ) connected between controller an battery
  • BlueSolar MPPT 75/15 ( firmware : 1.50 )
  • VE.Direct Bluetooth Smart dongle ( rev2, firmware : 2.23, bootloader 1.10 )
  • Victron connect app for iOS 5,27
  • 50W Led strip acting as load connected through an amp-meter to load terminal off controller
  • Adjustable powersupply acting as solar panel connected to PV terminals of controller
  • No jumpers present in controller, all settings managed in the iOS app.

After disconnecting everything form the controller and letting it rest for some time i connect according to order in instructions; Load, Battery, "Solar panel".

When powering up, after a shutdown with load-on-state, and turning on the load ( electrically ) the following happens.

  • Voltage measuered with multimeter on battery terminals 13,13
  • Voltage reported by controller : 13.02
  • Voltage reported by BMV : 13.13
  • Battery current reported by BMV : -4,80 A
  • Battery current reported by controller : -4,40 A
  • Load current reported by controller : 4,4 A
  • Load current reported by amp-meter on load terminals : 4,78 A
  • Controller becomes lukewarm within 30 minutes
  • Voltage on controllers load terminal is about 1,5 V lower than on controller battery terminals

At this time the load is active and the led strip is lit up.

When I switch to a load configuration that should cut off load, either "always off", a custom setting with a cut of voltage higher than current battery voltage, or with a shutdown in load-off-state the folling happens:

  • Battery current in app changes to 0 A
  • Load state in app changes to Off
  • Load current in app changes to 0 A
  • Load current in BMV stays the same
  • Load still on, led strip shining.

Switching on the load, either using "always on" or a custom setting affects nothing excpet load state in app now shows On.

All this is regardless of settings for the Tx/Rx-ports and street light. It's also independent of "solar panels" voltage, i.e. charging or not.

Key findings:

  • Load seems fixed at on-state regardless of relevant settings.
  • There is a slight discrepancy in current reading between battery and load, load-current is 0,4 A lower than battery-current according to controller.
  • About 1,5 V voltage drop between controllers battery and load terminal
3 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

ejrossouw avatar image ejrossouw commented ·

@pontus Thank you for the info. It sure is not something obvious. What intrigues me is that all the app measurements indicate off, however there clearly is still energy flowing. Can you provide a picture of the equipment and connections. It could also be worth removing the LED strip and then get multimeter readings from the load connectors in an on and off state. Best to start from factory reset when doing so just to ensure a good baseline.

0 Likes 0 ·
pontus avatar image pontus ejrossouw commented ·

I will try to get a picture of the set-up. Basically it's all wired with 2,5 and 4 mm^2 multistrand (RKUB), each connection 0,5 meters or less. Voltage at load terminal stays the same (with and without load) when toggling always on/of. Not even a flicker.


In-app-reading of load current is, compared to other things now, not of a big concern. Problem is load cut-off not working, manual or "programmed" possibly wrecking my LiFeYPO4 battery.


It doesn't make sense that load cut-off does not work, regardless of wires used.

0 Likes 0 ·
ejrossouw avatar image ejrossouw pontus commented ·

Hi @pontus In a very interesting twist of events I last week ran into exactly the same problem with a 100/20 for a customer of mine. I now suspect a possible HW issue of some sorts. I will follow up with Victron and propose you contact your supplier for a replacement. I have not been able to resolve the issue either and two other units I tested it on performs flawlessly.

0 Likes 0 ·
pontus avatar image
pontus answered ·

I bought the regulator 2015-05-15 (from https://www.voltpower.se/) for a solar charged cargo bike -project, that never took off. And it has been in storage since the summer of 2015. Now, when i bought a new LiFeOp4 for another project i picked up the controller again, discovering this load-cutoff-issue.

Is it even worth sending it back after five years? Whats' the warranty time on these controllers?

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

ejrossouw avatar image ejrossouw commented ·

@pontus The warranty is 5-years, but there is room for discretion from the dealer end. Given it just passed that time and what you told me, I'd definitely ask them to consider replacing it.

0 Likes 0 ·