Volvo Penta d1 MDI box vs BEP VSR vs Solar panel

[ynot 52]

So apparently Volvo have said that the main cause of MDI box failures is caused by solar panels attached to the system and the voltage getting higher than 13.8v which kills the MDI  which in turn stops the motor and won't start or charge or do sweet bugga all unless you get out the screw driver and short the relays old school...and yes I know how to wire the emergency start button but that voids warranty so  if the above  is true how do you get around a solar charger charging AGM's at 14.7 which will keep the VSR engaged which also means the start batt see this as well (SLA) and if both power switches are on with solar panel attached this must mean that the MDI box see this high voltage at times as well.

I am guessing the VSR can be engaed and back feed from house to start as well...i do not really know how they work  

If all this is right, then surely Volvo must have built a box that can handle a certain percentage of over voltage knowing that they sell boat motors, and most boats have solar and newer type batteries such as AGM and VSR's and things.

I asked them today if the box could be ditched and set up relays for glow and stop and start and gauges and alarms etc. but they said NO WAY it voids engine warranty. I wonder where they would sit if it really happened at the worst time and ya lost ya boat or family members when they are well aware of the issue that is in an issue solar or not.

I have also read that relocating them off the engine is a solve but Volvo says nope that is not an issue. 

I had one die on me under the harbour bridge with no boom on the boat (mast was coming out) on a no wind day so had to call coastgaurd and get a tow.

Thanks

I have attached a pic of what I am talking about of a possible setup that may cause this to happen.... any thoughts on how to set this up would be appreciated.

 

[aardvarkash10 1,056]

I'd have to say that if the device can't handle more than 13.8v, that's almost criminally poor engineering and that you may have recourse under consumer law if they have put that in writing after the purchase not before.

[Jason128 6]

Silly question, but is it possible to add a voltage regulator before the motor ecu?   Surely the main feed to the starter/ Alternator are seperate to the ecu feed, or can be carefully jumped into with the right matching plugs? That would sort the problem, and if a plug in part can hardly effect any warranty. 

the reality is no supplier can say a warranty is void due to a modification is if that modification  has caused the failure.   It’s like those stupid stickers that say warranty void if removed.

[aardvarkash10 1,056]

Did find this:

As the only supply from the battery is terminated at the starter motor solenoid, this is likely to be valid for all the engines using the MDI module.

Looking at some of the key components like the NCV4269 linear voltage regulator producing the 5VDC supply, and the 63V-rated filter capacitors, the module seems to have been designed around a 60V peak supply voltage limit. A number of other parts I identified had higher voltage ratings. I didn’t find any large capacity transient voltage suppressors anywhere, so it seems quite clear that Volvo opted to design for a sufficiently high peak voltage and I also think it is the most robust option in this context. 60V should be ample considering that the cables to the battery are normally both quite short and substantial. Longer and/or undersized cables could allow the voltage to spike more at the engine, but even then the available margin seems quite considerable.

One potential scenario that could lead to the electrical destruction the MDI box is an alternator load dump caused by the loss of the battery while charging at high current. In this case, the surge could easily exceed 60V, especially with the standard Volvo wiring which also connects the alternator output (B+) to the started motor solenoid.
In most cases, it makes sense to run a new dedicated heavy cable from the alternator B+ post to the battery, or – better – to a battery isolator for charging separate banks. This normally mitigates or even entirely eliminates this possibility.

 

https://nordkyndesign.com/engine-reliability-a-look-at-the-volvo-penta-mdi-black-box/

[CarpeDiem 507]

My $0.01 worth, Bollocks to the engine warranty being void. If that was the case then that would mean that the old school screwdriver trick would void your warranty...

My next $0.01, I recommend taking the box off the engine and mounting it somewhere not attached to a 80degC vibrating heater  Probably not the solution but it can’t hurt. 

I have also heard the over voltage theory but never seen anything formal from VolvoPenta.  The other theory I have heard is the starter motor load dumping into the box.  I know of three people whose black box died after excessive cranking, coincidence... maybe, maybe not. 

Are you preheating the engine before starting it?

If you have the start isolator closed then you cannot stop the mdi from "seeing" the voltage at the start battery without modifying the volvo wiring harness, and installing a regulator, and then you're back to the warranty issue... and in an arguably worse failure scenario than installing three simple buttons.

You can get dual sense vsr's. Or single sense vsr's. Sounds like you have a dual sense one.  Depending on what you want to achieve you could swap that for a single sense or maybe it is configurable.

Fwiw, I sometimes, when at the marina, trickle charge my start battery at 12.8v that's all it gets.  I never charge it when we are out.  It's 7years old and has never gone below 9.6v when starting the engine.  It will probably die next week now I have said that...

 

[Island Time 1,278]

2 hours ago, ynot said:

So apparently Volvo have said that the main cause of MDI box failures is caused by solar panels attached to the system and the voltage getting higher than 13.8v which kills the MDI  which in turn stops the motor and won't start or charge or do sweet bugga all unless you get out the screw driver and short the relays old school...and yes I know how to wire the emergency start button but that voids warranty so  if the above  is true how do you get around a solar charger charging AGM's at 14.7 which will keep the VSR engaged which also means the start batt see this as well (SLA) and if both power switches are on with solar panel attached this must mean that the MDI box see this high voltage at times as well.

I am guessing the VSR can be engaed and back feed from house to start as well...i do not really know how they work  

If all this is right, then surely Volvo must have built a box that can handle a certain percentage of over voltage knowing that they sell boat motors, and most boats have solar and newer type batteries such as AGM and VSR's and things.

I asked them today if the box could be ditched and set up relays for glow and stop and start and gauges and alarms etc. but they said NO WAY it voids engine warranty. I wonder where they would sit if it really happened at the worst time and ya lost ya boat or family members when they are well aware of the issue that is in an issue solar or not.

I have also read that relocating them off the engine is a solve but Volvo says nope that is not an issue. 

I had one die on me under the harbour bridge with no boom on the boat (mast was coming out) on a no wind day so had to call coastgaurd and get a tow.

Thanks

I have attached a pic of what I am talking about of a possible setup that may cause this to happen.... any thoughts on how to set this up would be appreciated.

 

Volvo where and who? The MDI units "should" be ok up to around 15v which is when the Alarm goes off. The MDI should be powered off when ignition is off. Volvo are well aware of the issue and issued the attached recall. Your dealer is not being straight up! Its worth reading the link above from Eric at Nordkyn. There is also lots of stuff on cruisers forum. Print out the attached recall, and maybe some other stuff, and have a go at your dealer. I have had 2 MDI's replaced under warranty...

MDI BOX RECALL.pdf

[ynot 52]

Yes It I agree... It seems like horse sh*t thay they would try to blame it on solar.... No issue here with the dealer all is good and being looked after. So you are saying your one is "seeing" voltages up to 14. 7 as well? Nm... Is yours still mounted on engine when 2 have died? 

CD....is yours still mounted on engine... I probably will move mine because it would be easier to get it if happened again. 

I read all lot of the Nordkyn stuff... All very interesting but I cannot find anything definitive on what actually goes kaput in them which I would have thought considering the amount of mdi deaths someone would have by now. 

Guess I'll go through all the bits mentioned like relocate, batt connections etc and try again. 

Is a vsr the right thing to use... Seems odd that sparky who fitted it said yes it is when clearly there are two battery types being kept and charged by the vsr when using solar sometimes up to 14.7 and treated as the same bank.... I thought a vsr split the charge but after reading myself it seems they only lock the banks together. 

Must be a better way.

Ill check what vsr it is

Ta 

 

 

[ynot 52]

And yep always let preheat do its thing about 8 seconds 

[Young Entertainer 61]

my MDI lasted 5hrs,  after getting towed back in and some helpful advice from others with the same issue, i got Ovlov down to replace under warranty,  they told me they had never seen it before,  i let them know that google would disagree.

What has always intrigued me is that they replaced my battery cables as part of the install, apparently it is recommend by Volvo.  I was happy i had when it died as they did try to blame it on other things in the boat and i reminded them that they did the install an i agreed to all there recommendations.

I had the "safety button" on alligator clips so that there would be no evidence left behind if I needed an emergency start. i have no idea how they have got away with this for so many years, especially in the US

[CarpeDiem 507]

3 hours ago, ynot said:

Is a vsr the right thing to use... Seems odd that sparky who fitted it said yes it is when clearly there are two battery types being kept and charged by the vsr when using solar sometimes up to 14.7 and treated as the same bank.... I thought a vsr split the charge but after reading myself it seems they only lock the banks together.

Mine is off the engine. I have never had it fail (touch wood).  I have also set up three buttons for the day it does. Glow, Start, Excite.  I am not worried in the slightest about the threat of a void warranty. 

You're right about the vsr. It's not possible to optimally charge two different types of batteries with one charging source there will always be a compromise.  I don't use a vsr for that reason.

 

 

[Island Time 1,278]

I too have a set of wired in bypass switches to enable start and alt when it fails again. Yes, my alt used to output 14.75 (with old AGM's that could take 14.8v, with alt being controlled by the Nordkyn alt controller to get 3 stage charging. When I changed to lithium (LiFePo4) the max voltage was restricted t0 14.2v, and solar to match.

VSR - yep, just joins the banks together. Not ideal if batts cannot operate at same voltages

If your chemistries require different voltages, the best way is to set up for the house bank (Where most charging is required), then use a DC-DC charger to the start bank. IMO.

[ynot 52]

Guess I'll set up permanent buttons then easy pezy... Still sucks though. 

I'll look into dc dc charger as well. 

Thanks for input guys 

[Screwball 5]

Just for another data point, we purchased a second hand D1-20 still in its crate about four years ago. Can't remember the exact model year but it was definitely near the start of the run so quite an early version of the MDI (seems like Volvo's been through more than a few versions in an attempt to get them to stop dying). We mounted the MDI off the engine from the beginning and it hasn't skipped a beat so far (touch wood). Considering most 12v alternators (included the stock one) output at least 14v their assertion that voltage higher than 13.8v are the culprit doesn't make much sense to me.

[mattm 104]

Agreed Screwball. Who ever said 13.8v kills them doesn’t know what they are talking about. Their own alternator supplies over 14v. Actually, reconsidering, maybe they do know what they’re talking about….