question

svbravo avatar image
svbravo asked

Cause of total system shutdown???

Looking for answers on what could be the issue with our Victron system...(3x 200Ah "Smart" lithium batts with Victron BMS, BatteryProtect, BMV and Color GX monitors, Quattro inverter/charger, MPPT controllers, etc.....all Victron).
A couple of weeks ago, we were hit by a heavy squall, with 35-40kn true wind on the nose, in large confused seas. The autopilot, an NKE driving an L&S hydraulic ram was struggling with the excessive weather helm. Just as we were preparing to put in a 3rd reef, the entire boat "went dark" without warning. No autopilot, instruments, gps, radio comms, or lights.....all 12v circuits on the boat were dead! And just as we really wanted the autopilot to keep driving as we tucked in another reef. The boat was on her ear, (we later found seaweed draped over the leeward lifeline!!!). As we struggled to regain control, all of a sudden the boat "lit up".....all 12 volt circuits started up again!!! YEE HAH!!! we did a quick happy dance!!! But our happiness was short lived, as the cycle of off/on happened 3 more times over the next hour or so. Visibility was very poor, as the rain got heavier. We started the motor (it has a dedicated starter battery) and dropped the mainsail for the last bit of the overflows. At last we rounded the Mull of Galloway and gladly headed north. Conditions have been comparitively mild since then, and the problem has not recurred.
So what happened to our electrical system? After all, having the boat shut down like that at the wrong time could be disastrous. Had this occurred at night, in shipping lanes, ships tracking us on AIS or visually by our lights would not have known we were out there. And similarly, we would have been "blind" without radar or AIS to spot ships. While we still have no definitive answer, at this point all signs point to the Battery Management System (BMS) of the lithium battery installation. It's the only thing which would shut off all of the loads like this. The job of the BMS is obviously to protect the batteries, and will shut down all loads on the system if it senses low overall system battery voltage, overheating of the batteries, or cell imbalance between individual cells in the batteries.
According to the installing electrician/dealer, he feels that the system was "operating normally"!!! That given the struggle of the autopilot in these wind/sea conditions, it is possible that the demands on the battery bank MAY have caused a cell imbalance which caused the BMS to shutdown, even though the overall battery voltage was fine (we'd been charging while hooked to shore power for 3 days so had been 100% only 2 hours earlier).
I am having a hard time thinking of this as "normal operation". Normal operation of critical systems cannot simply shut down without warning, or the system is not suited for purpose!!!!! And also that a cell imbalance could have been brought on by excessive load on the batts. (the autopilot only requires a 30 amp breaker....at 12v, that's just 360 watts, .05c, far less than the load imposed by an induction hob or microwave which we often use for longer periods through the inverter without effect.). While of course I was a bit too busy to check the individual cell voltages with VictronConnect during the shut down, whenever I check the voltages at other times, the 12 cells are all within .01 volt of one another. Any ideas of what could have caused this shut down (it has not happened since)??? And what could prevent it in the future? I am thinking of installing a battery switch in parallel with the terminals of the BatteryProtect relay, normally kept open, in case of another emergency shutdown, though I have been advised that it's use could void the warranty! Any suggestions are welcome!
Battery Protectve.bus bms
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5 Answers
markus avatar image
markus answered ·

Hi,

this is a very impressive but dangerous story. And indeed, this should not be happening.

Can you please provide more details on how your 12V equipment is wired to your battery?

Do you have a DC-DC converter or a Battery Protect device in between the loads and the battery?

Do you have a Victron GX device onboard?

There are indeed methods to implement, to prevent this in future, but we need more infos to figure out, what have happened.

Best Regards,

Markus

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markus avatar image markus ♦♦ commented ·
Ah, I just noticed you have a GX. Was it possible to investigate the events on VRM?
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svbravo avatar image svbravo markus ♦♦ commented ·

I tried this, but unfortunately I don't think the VRM records individual cell voltages, just overall bank history. (I'd love to be wrong on this!!!). I know that the overall bank voltage was fine, as I'd just unplugged from shore power a couple of hours earlier. So it remains possible that the individual cells were imbalanced by the autopilot pump, but I cannot see this on the VRM.

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shaneyake avatar image shaneyake svbravo commented ·
I don't have a victron BMS but a CAN battery, if I go to advanced in VRM and in the widgets menu, under Battery, I can enable the Min/Max cell voltage view. I would imagine Victron BMS would have this too.
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svbravo avatar image svbravo commented ·
Hi Markus. I'm not at the boat now, so will need to get back to you with more specifics. But, yes, we do have a Battery Protect controlled by the BMS (all Victron). I believe that the problem lies in one of these 2 devices, which would cause the system to shut down like this. (FWIW, the system was professionally installed by an experienced Victron certified electrician, who has done many of these systems before ours.....though I know anyone can make a mistake!!!)
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Mike Dorsett avatar image
Mike Dorsett answered ·

Having lived on a sailing yacht for 11 years, and sailed 57,000 miles with 2 pob, Our only auto pilot problem was a stripped gearbox - 1/4 horse 24V dc motor turning a Whitlock Mamba system. A possible cause of the blackout may be excessive current draw from the hydraulic motor, due to the heavy conditions. Whilst the batteries themselves are rated for 200/400A, there may have been voltage drop in the interconnects?

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svbravo avatar image svbravo commented ·
Could be voltage drop, as I told Michel above. I'll check the cable size, but think it is probably ok, as the same system has been installed on the same boat model many times before, and the boats are high latitude exploration boats, with many voyages to Antartica and the arctic. And I too, have been cruising full time for nearly 11 years now (on our previous boat, also with lithium batts), and this is the first time I've had this problem.


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michelg avatar image
michelg answered ·

Hi, in my opinion it is related to the SmartProtect (battery protect) that has shut down any power. Probably due to the consumption conditions the power / voltage was unstable and triggering the protection or the cabling unable to handle the required Amps and heating, taking the voltage / power to a level that the BatteryProtection did trigger.

The fact that the power came back and that the issue happened a total of 4 times seems to point either a misconfiguration of the BatteryProtect, or a problem with the wiring not supporting the load during such situations. Check all your connections and cable size, if they are fine and adapted to handle the Amps.

Michel

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svbravo avatar image svbravo commented ·
Hi Michel. I am sure that it was the Battery Protect that shut down the system. But I am not sure of why it works fine when using the electric induction hob @ +/- 1000W, or the microwave at 800W, or even a space heater at 1250W, but had a problem with the autopilot loads, which go through a 30A breaker (360W max at 12V) and the breaker did not trip. Perhaps it is a voltage drop to the hydraulic pump. I will check the run length and cable size to be sure. Thanks.


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2hulls avatar image
2hulls answered ·

Just recently joined this community and just saw this discussion.

I had a similar event 1 1/2 years ago in less stressful conditions. Was talking to my weather router on the SSB when the genoa (alone) gybed in light conditions and the AP went hard over trying to adjust. I let the boat founder in the light conditions as I wanted to continue talking to the weather router. We were basically hove to. Then all power went out. I still had battery voltage as indicated by my 712 BMV (wired for always ON). I cycled the house bank disconnect switch with on effect and began to get the boat settled back on course steering manually when everything came back on. It had been about 2-3 minutes. No obvious causes. I concluded the house bank output battery protect and VE.Bus BMS were the likely culprits, reacting inappropriately to the "transient". This was not a high current event. The SSB does draw quite a bit when Tx on high power - which I was, but the AP linear drive has a limit switch. Other loads running were two refers and nav equipment. Nothing big.

My system is a very simple all Victron with 3 160ah LiFePO4 batts, Multiplus, 712 BMV, 150/70 MPPT, main out put BP, BP on MPPT and BPs on each engine large alt regulator. The only things that could have done this are the BMS/Main Bank output BP.

It has never happened again under numerous, much more trying loads. Had just rounded Cape Fear, so were not inside the Bermuda Triangle. :)

Dave

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indianna avatar image
indianna answered ·

I am experiencing a similar problem when the boat is under way and the microwave is turned on (microwave running from inverter). In about 30% of the times the microwave is used the Smart Battery Protect momentarily shuts down all 12 Volt DC loads running through the battery protect. The power for the inverter does not go through the battery protect. I feel that the inverter is emitting a pulse, perhaps airborne, that turns the battery protect off momentarily. Any helpful suggestions would be greatly appreciated.

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