Continuous Soft Start Cycle: Balmar MC-614

[marty9876]

Hi all, any ideas before I call support again would be greatly appreciated!

I’ve got a Balmar MC-614 regulator which seems to be going through a continuous soft start ramping cycle. Starts from no amperage and ramps up to what the batteries will take (40+ amps etc. depending on SOC) over 40-60 seconds, stays there for a few seconds then cuts all charging and starts the process over and over.

I called support and their recommendation was to disconnect battery temp sensor, which I did and problem went away. Cool, replaced temp sensor and all was well for ~ 15 hours of usage and now the problem is back. Disconnect the new battery temp sensor and problem goes away. Resistance on new and old temp sensors measured .4 ohms apart for what that’s worth, threw old sensor away.

History- regulator is 1 yr old, battery and alt temp sensors installed. Just switched to new gel batteries from AGM (basically when problem started this year, seasonal use boat). Custom program in the regulator per Compass Marine recommendations for gel. Amperage measured via two monitors (just installed Balmar SG-200 also) and I can hear the load on the motor change so I know the alt is really ramping up and down. Alt is a Compass Marine 80amp.

[sailorboy1]

well you know the problem, it's the temp sensor

[a64pilot]

I’d still call. Two failures like that is odd.
I had mine do something weird a year or so ago, it went to something crazy like -35 temp and of course the voltage set point was crazy high, disconnected the sensor and reconnected it and it hasn’t acted up since.

Mine did not cycle however, the voltage was actually within limits as the temp sensor on the alternator keep output low enough and bank would not accept a stupid high voltage either, but you could see the numbers of course on the 614’s display.

If I understand the temp sensor, it shouldn’t cycle like that, unless of course it’s cycling into and out of a bad reading, watch the temp display on the 614 and see if it changes

[sailorboy1]

Originally Posted by a64pilot

I’d still call. Two failures like that is odd.
I had mine do something weird a year or so ago, it went to something crazy like -35 temp and of course the voltage set point was crazy high, disconnected the sensor and reconnected it and it hasn’t acted up since.

Mine did the opposite. It decided the alternator was hot (didn't even have the sensor) and clamped the amps down to only 30. Tried all the hard and soft resets to no improvement and had to replace it (was only a couple years old). But I kept it as it still works and is a backup.

[marty9876]

I’m thinking (hoping) its an install problem. Per manual “Connect the sensor lug to the battery negative post closest to the center of the battery bank. Extend sensor cable to the regulator”

For some reason I’m pretty sure I have the temp sensor got the MC-614 at the end post which this negative for the house circuit connects to and all the other temp sensors (solar, shorepower) sensors in the middle of the bank. Fingers crossed it’s an easy fix. Strange it seems to come and go but if it’s fixed moving the position I’m a happy guy.

[sailorboy1]

Personally unless you have a real high output alternator I don't see the need for a temp sensor. I have a 100-amp unit that I derated on the programing to 90% due to the belt. But in 2000 hours and 9 years have never seen do more than 75 amps because that's all the batteries will accept at 70% SOC

[smac999]

Do you have an acr in the system? Does alt feed direct to house bank or start bank?

This problem also happens with a cycling acr.


Location of temp sensor is not your issue. The battery in center might get slighter hotter. That’s why they tell you to measure that one. So your problem would be worse not better on center battery.

[marty9876]

Originally Posted by smac999

Do you have an acr in the system? Does alt feed direct to house bank or start bank?

This problem also happens with a cycling acr.


Location of temp sensor is not your issue. The battery in center might get slighter hotter. That’s why they tell you to measure that one. So your problem would be worse not better on center battery.

Yes - I have a VSR (voltage sensing relay) - I’m assuming this is the same as a ACR. It’s market as cut in at 13.7v and out a 12.8v. I left the original starter battery installed (agm) when I installed the gels.

Alternator directly feeds house bank. With it only pushing 40 or so amps and doing it this morning I’d be somewhat surprised if the battery terminal was heating up that fast, I might have been grasping at straws thinking terminal location was the issue. Having two temp sensors go out sounds pretty unlikely was my thinking.

[marty9876]

Quick update to close this out for future searches - reloading the regulators software seems to have fixed things. Change battery type, save, change it back and plug in settings life seems to be good. Bad load/save of the program prior apparently, software is saved in read only memory on the device.

Little bumbed I threw away a good battery temp sensor, could have used on start battery but all in all cheap in boat terms to troubleshoot

[a64pilot]

Thank you for reporting the fix, often we never hear what the resolution was.

[Stu Jackson]

Originally Posted by marty9876

Quick update to close this out for future searches - reloading the regulators software seems to have fixed things. Change battery type, save, change it back and plug in settings life seems to be good. Bad load/save of the program prior apparently, software is saved in read only memory on the device.

Little bumbed I threw away a good battery temp sensor, could have used on start battery but all in all cheap in boat terms to troubleshoot

Good to hear, thx for reporting back.


reloading the regulators software --- how do you physically do that, or do you simply mean start all over?

[marty9876]

Originally Posted by Stu Jackson

Good to hear, thx for reporting back.


reloading the regulators software --- how do you physically do that, or do you simply mean start all over?

Change battery type, wait three scrolling cycles and the unit will save the new programming. The process of saving the new programming is reloading the software. Look for SAV to show.

The device has stored copies of the original programs saved in read only memory, changing battery types and saving it causes a reload of those original programs. Sometimes you can get a bad load I guess.