[Nmstec]

Folks, I have been using Volvo Pump in my electric Jag for about 2 years in fail-safe mode but I was looking for way to control speed. Thanks to contributions of fine members of this forum I was able to add some control through my Arduino DUE based VCU.
I wanted to share few observations.

With following messages: 0x02104136, 0x1ae0092c I am able to control speed between (I estimate) 50-100% for speed parameter 0-5000 (5000-6000 makes no change for me). In fail-safe mode, my pump runs at 50% speed (or equivalent of speed parameter 5000).
One thing I was not able to achieve with those two messages was instant start of the pump, there was always annoying 3s delay.
So, I replayed messages from log posted here while ago and isolated message which forces instant start of the pump, it is 0x0300410e
In the log this message is sent with constantly rolling values of all bit but I found single set of values I can send to trigger instant start: {0x38,0x23,0xb8,0x36,0x47,0xc7,0x6c,0x00}.
This message can be sent with interval between 1-100ms in addition to two other message and my pump starts immediately.

I noticed when controlling speed with message 0x02104136, pump responds very slowly, it ramps up/down in few seconds.
I found out that pump responds instantly to message 0x0340412e but I do not know yet which bytes are responsible for speed. More research may be required to discover all the aspects of controlling this pump but what we have already is really useful.

NMSTEC/Volvo_EPS_FREE (github.com)

Heres your answer!

 

[arturk]

NMSTEC/Volvo_EPS_FREE (github.com)

Heres your answer!

Awesome! Thanks for sharing.

 

[Jeep Man]

Can I bring this post back to life please.

I'm working on converting older Jeeps to all EV and use the Volvo PS unit.

I'm getting a condition that that pump will start fine then seemingly at random, just turn off.

All my 'team' are pretty sure it's related to voltage and possible a voltage drop that kicks it off but then restarts on it's own when it 'sees' that the voltage is back up to snuff.

I'm being broad in my description but what do you think, could I have accidently starved my pump with a smaller 12v battery that doesn't have the CCA to make this pump work?

ANY thoughts in this area would be great - thanks.

- Patrick

 

[joekitch]

If you can log 12v voltage at the pump over a period of time and watch the pump die off, and you see a big voltage sag in the 12v system at the same time, then yeah it probably isn't keeping up

Although if that was the case I'd expect it to die often when you turn it to full lock

 

[Jeep Man]

If you can log 12v voltage at the pump over a period of time and watch the pump die off, and you see a big voltage sag in the 12v system at the same time, then yeah it probably isn't keeping up

Although if that was the case I'd expect it to die often when you turn it to full lock

Funny thing is, it does die when driving it also, mostly noticeably when I am turning or, strangely, about to turn.

I have a scope, I'm shit with it, would you put it on the 12v+ side and watch it (over simplificaiton but...) that way?

I think what seems to trick me is it's start up cycle is stepped so when it kicks off, it doesn't necessaryly turn right back on, it takes a couple seconds. In that time, you can't properly tell what's happening.

I know the pump stores it's own faults (smart pump!), but I have no way to get that data out without a full CAN interface (looking into that with this: NEW Automatic GPS | Volvo C30 C70 S40 V50 power steering controller kit ).

So, what do you think, man up and figure out how to make my Riogol DS1054z do what it was born to do?

- Patrick

 

[Jeep Man]

After staring at it for hours - it's the 12v SLAB battery. I'm convinced.

My searnio:

• Everything is charged up and loving each other (including the Pack)
• Key ON, pump starts
• Runs in Limp-Mode, at full pressure to build up for anticipated use
• All other normal 12v events happen - water pump (Tesla Model S), cooling fan, BMS (minor draw), radio, whatever.
• PS pump is working normally when it draws down the 12v

Battery: SLAA12-35C Duracell Ultra 12V 35AH General Purpose AGM Sealed Lead Acid (SLA) Battery with M6 Insert Terminal, looks like this:

It was a vendor recommended purchase. It's small, Length: 7.68 in, Width: 5.12 in, Height: 6.57 in, that's partial why I bought it.
- Pump turns off, seemingly at random then, about 2-5 min laters, it starts back.

What I think is happening: the pump drains the battery below 12v nominal, the DC/DC Enable attempts to kick in but is stopped by the lack of power to the DC/DC watchdog and fails to start charging right away. This has a chain reaction and begins to let other 12v dependent parts likewise drop out - pump, fan, LV-JB. During this time, the stock amp meter in the vehicle, which works to indicate 12v battery state (stock wiring, it just works as part of the existing system, no special work to gauge), it flickers to the charge / no-charge states. Also, at the same time, the BMS is trying to test it's Safety relays, I can hear the clicking as it attempts to do stuff.

Possible solutions:

1. Replace the 12v battery with a similar one that's deep cycle
2. Replace with larger, group 24 or so
3. Move back in with my mom and call it quits.

I'm going to try #1 first.

Thoughts?

- Patrick

 

[Jeep Man]

Along those lines, does anyone have a recommendation for a smaller form factor 12v SLAB?

The one I'm using that is causing me headache is 35Ah. Seems low to me also.

Thanks