Volvo D1-30f voltage alarm

[Monty1]

Does anyone know how to permanently disable the voltage/battery alarm on a Volvo D1 30 F engine ( the one with the MDI unit)

As I am having problems with the battery alarms going off on my Volvo D130f engines when a large electrical load is put on the alternators and the MDI units sense a temporary voltage drop and as I have Lithium batteries I do not get a large voltage drop or increase when a load is put on the alternators.

[colemj]

If the voltage doesn't drop, then why is the alarm going off?

Sorry, I don't have the answer, I was just curious about the above.

Mark

[Monty1]

That I don't know either!? The voltage does drop a little when a load of say 150 amps or more is put on the alternators but not a large amount as it did with lead acid type batteries.

[DougR]

Couple of questions:
Does the alarm come on and stay on? Or just come on momentarily when the load is applied and then go back off?
Do the alarms sound on both engines?
Are you running the standard alternators with standard regulators?
Is there any sort of "smart" regulator or splitter in the system?
What is the battery bank arrangement? Start banks, house banks, etc. and how are they connected together?

90% of the VP charge alarm problems that occur with both older and MDI systems are the result of "smart" regulators controlling either Volvo or aftermarket alternators. When these regulators sense that the batteries are fully charged the regulator goes into float mode and reduces field current to the alternator to limit voltage output. This limiting is sensed by the alarm system which then sounds the alarm.
In your case it sounds like you are getting a momentary voltage drop which is deep enough to cause the alarm system to engage. This can sometimes happen so fast that the only way to see it is with an oscilloscope.
The MDI system charge alarm works on both under voltage and over voltage. Early boxes had a somewhat high " low voltage" trip point, and supposedly this was changed in later production to avoid nuisance alarms, though that would require some checking and verification.

Give me some answers to the above questions.
DougR

[Monty1]

Hi DougR
The alarms come on and stay on until the load is taken off. They also come on as you say when the Balmar regulators drop the field voltage right down when in float mode (13.6 v) both alternators (catamaran) or one.
The alternators are non standard 165 amp 12 v and the regulators are Balmar ARS 5
The battery bank is a 450 a/h lithium from lithionics with its own BMS and internal cell balancing.
Both engines are linked to this bank and currently I am only using this one bank for start and house.
The charge from the alternators goes to a common buss bar with other sources on it also.Solar, Watt and Sea hydro etc
The alarms come on either with heavy loads or when the regulators are in float with low loads of say 30 amps.
I think the best solution could be to disconnect the voltage alarm part of the MDI system if this is possible. The BMS system for the Lithiums will look after any high or low voltage events and give me an alarm so I don't really need the MDI one. I do still need the oil pressure and high water temp alarms and of course the tacho's. Do you know of a way to do this or have any other ideas?

[Monty1]

Hi DougR again
Sorry, I forgot to say that with the Lithium pack I don't get the sudden voltage drop that could occur with lead acids and when the alarm was going the Balmars were reading 13.3 v
The battery voltage also climes more slowly even though they are taking the maximum load that the alternators can give. Only when they are nearly full 98% does the voltage rise quickly.

[colemj]

Ah, you didn't say that you were not using the standard Volvo internally regulated alternator. Yes, this is a well-known issue with external regulation on these engines. I don't know the solution, but do know there was a thread on this a while back where someone did solve his similar problem after a lot of trial and error work.

Mark