Balmar Duo Charge blown fuse

[dhays]

This weekend my thruster/windlass battery bank died while raising my anchor. Fortunately, we were anchored in shallow water.


Since I've owned the boat the 2 Lifeline 8D batteries that power the windlass and thrusters has been charged using a Balmar Duo Charge. This is a DC/DC charger that will pass charge current from a house bank under charge, to an auxillary bank, typically a starter battery. This has worked really well on this boat for years on both the thruster/windlass bank as well as the genset start battery.


The Duo Charge has a couple limitations. The first is that it will only charge at a max of 30 amps. The second is that if the auxillary battery bank asks for more than 30 amps, it will shut down, wait for a bit, and then try again.


I found two things. The Lifelines had a voltage of 10.5v. Secondly, the 30 amp fuse between the Duo Charge and the thruster bank was blown. It had gotten so hot in the process that I'm not sure I trust the fuse holder anymore.


So I have two questions. The first is why would the fuse blow? Did the Duo Charge fail to shut itself down if the thruster bank asked for more than its 30 amps?


I happen to have another functioning Duo Charge that I could use if I choose. The only problem is that with the Lifelines dead, a functioning Duo Charge will likely not charge them because they will be asking for more than 30 amps. I would need to find a way to charge the lifelines first.


My other alternative is to use an ACR to connect the house and thruster banks.


Any electrically wise folks have suggestions?

 

[Ka_sea_ta]

I assume that your thruster and windlass is 12 volts, if your house bank is the same chemistry(AGM) then why not use an ACR.... It appears the thruster bank has not been charged in awhile, so probably the fuse may have failed awhile ago check the holder and wiring.... A second thought would be to put the other duo charge in parallel with the original.... If it were me I would want the higher charge current available with an ACR to supplement the available power from the batteries with alternator when using the thrusters or windlass.

 

[dhays]

I assume that your thruster and windlass is 12 volts, if your house bank is the same chemistry(AGM) then why not use an ACR.... It appears the thruster bank has not been charged in awhile, so probably the fuse may have failed awhile ago check the holder and wiring.... A second thought would be to put the other duo charge in parallel with the original.... If it were me I would want the higher charge current available with an ACR to supplement the available power from the batteries with alternator when using the thrusters or windlass.

Yeah, I am leaning towards the ACR for the reasons you mention.



Dave

 

[Comodave]

Is the wiring large enough to support the 30 amps without a voltage drop? I always go oversize on wiring that carries a large load just in case and also so I actually get the best voltage possible to the item I am powering.

 

[dhays]

Is the wiring large enough to support the 30 amps without a voltage drop? I always go oversize on wiring that carries a large load just in case and also so I actually get the best voltage possible to the item I am powering.

Yes. The wiring is that which is supplied by Balmar and is only about a foot long with the fuse holder. Not sure, but I think it is about 8 gauge. It then connects direction to the battery cable.

 

[Aquabelle]

I have two DDCs which charge my genset and start/cranking banks. The 30A fuse blows eventually after long periods of on/off operation resulting from the target battery wanting more than 30A. As you have 2 x DDCs, you could do as I do and parallel them to give more capacity IF your two target batteries are the same chemistry. The Balmar official solution is to use the dedicated terminal on the DDC to drive a solenoid which allows as much current as you want thru to the target to charge it up quickly....then when demand falls back below 30A the DDC reverts to its battery chemistry-specific charging profile.

Sounds like you cannot parallel each of your battery banks with at least one other. You may want to add that feature for just the emergency situation you found yourself in.

 

[dhays]

I have two DDCs which charge my genset and start/cranking banks. The 30A fuse blows eventually after long periods of on/off operation resulting from the target battery wanting more than 30A. As you have 2 x DDCs, you could do as I do and parallel them to give more capacity IF your two target batteries are the same chemistry. The Balmar official solution is to use the dedicated terminal on the DDC to drive a solenoid which allows as much current as you want thru to the target to charge it up quickly....then when demand falls back below 30A the DDC reverts to its battery chemistry-specific charging profile.

Sounds like you cannot parallel each of your battery banks with at least one other. You may want to add that feature for just the emergency situation you found yourself in.

Good points.


I can parallel the Genset start battery or the engine start battery with the house if I need. I don't have the ability to parallel the thruster bank with the house bank. That is something I need to look at.


I'm also wondering how well the Lifeline 8Ds will come back after such a large DOD.

 

[Aquabelle]

They will have lost 50% of whatever their remaining cycles life was immediately prior to the incident. So if you had say 3 more year's life left before, you are now down to months....according to most manufacturers.

 

[dhays]

They will have lost 50% of whatever their remaining cycles life was immediately prior to the incident. So if you had say 3 more year's life left before, you are now down to months....according to most manufacturers.

Yeah, kind of what I was afraid of. Not sure how old they are. They certainly aren't original but I'm thinking they are at least 6-7 years old. It may be time to look at replacing them.


I keep thinking about just scrapping the 8Ds and adding another pair of L16s to my house bank and then just using the house bank for my thruster and windlass as well.



Pros: Simpler system, larger house bank (1170 vs 780), larger effective thruster bank (1170 vs 500), less weight (~60 lbs), be rid of the monster 8D batteries.



Cons: Large bank to charge which would likely increase charging time to 100% (less time at bulk than a smaller bank), current house bank batteries are a year old so it would mix ages of the batteries, 1 pair of L16s would be separated by the other 2 pair of L16s by 6', creating uneven connecting cable lengths.

 

[twistedtree]

I think an ACR is the way to go. It won't be abnormal for the thruster battery to need a lot of charge. I think this little "feature" in the Duo is a fundamental design problem, and makes them useful for start batteries, at best. And even then the problem can arise if you need to crank your engine a bunch for whatever reason.

 

[dhays]

I think an ACR is the way to go. It won't be abnormal for the thruster battery to need a lot of charge. I think this little "feature" in the Duo is a fundamental design problem, and makes them useful for start batteries, at best. And even then the problem can arise if you need to crank your engine a bunch for whatever reason.

I agree about the 30amp cut-out being a problem. Now, this Duo Charge has worked on this boat for a lot of years with this being the first problem. So it really has worked pretty well.

I have no idea how electrical stuff works. I think that the 30 amp charging limit is fine, but I wish it was designed so that it still supply that 30 amps even if the battery bank wanted more. As it is, a Duo Charge will not charge up my thruster bank since it will ask for too many amps.

So, since I have a spare ACR and I have some spare 4/0 cables, I think I can pretty easily reconfigure the system to use an ACR.

 

[O C Diver]

I question the choice of start versus deep cycle batteries and maybe the charge rate. My thoughts:

I agree with the idea of a start battery for the bow thruster. A bow thruster is generally used for seconds with high amperage draw (like an engine starter). If you go to the trouble to calculate the momentary usage of the thuster in watts, you will find your refrigerator uses more watts per hour.

Now if you think about the amperage draw of an anchor windlass, possibly running for minutes, that's deep cycle duration consumption (all be it at much lower amperage). While it may not be practical to run the windlass off the house deep cycle bank or the engine battery (assuming the engine alternator can handle the windlass load), those would be better choices than the start battery you are using.

If I had to guess, the windlass batteries may have reached the end of their life or lost a cell. The charger kept charging at full output (never was able to bring the voltage up to reducie charging rate) until the fuse popped.

Ted

 

[Island Cessna]

Since it has run for years you should be looking for what changed causing it to quit, not looking at faults in the original installation.

The Duo Charge manual says the input and output wires are both 10 gauge with 30 amp fuses. All fuses blow after a duration of time at a particular amperage. If your Duo Charger has been running for extended periods at exactly 30 amps the fuse may not have blown, but the element is running at a temperature just below it’s melting point, and the clips in the fuse holder will be at the same temperature, oxidizing and loosing their tension. The result is increased resistance in the junction with the fuse terminals, causing additional heat and the 30 amp fuse overheats and blows at an amperage below 30. The fix would be to replace the fuse holder.

While it violates my “ look for why changed” advice, this may be worth a quick look. The Balmar manual says that the input wire should be short, no longer than the supplied pigtail and the output wire should be 10 gauge, and a minimum of 8 feet long beyond the supplied pigtail. From their description it appears they use the resistance of the output wire as part of their regulation scheme. Quote from the manual: “the reason for the extra wire length is to act like an electric spring which allows the Digital Duo Charge to produce a higher current.” Do you have this length of 10 gauge wire? Since it has run for years I assume so, but worth checking, and adding length if needed.

 

[dhays]

I question the choice of start versus deep cycle batteries and maybe the charge rate. My thoughts:
.....
If I had to guess, the windlass batteries may have reached the end of their life or lost a cell. The charger kept charging at full output (never was able to bring the voltage up to reducie charging rate) until the fuse popped.

Ted, I know there is a lot of discussion of start vs deep cycle for thruster batteries. If someone had a remote batter in the bow next to the bow thruster, then a start battery(s) would make some sense. In my case, I have one bank that supplies both thrusters and the windlass. The PO chose Lifeline 8Ds. I am sure the reason he made that selection was that is what the yard that did the work recommended and supplied. My understanding is that those batteries are kind of a hybrid. Not a bad choice really. If the bank is sufficiently large, it can provide the high, short term demand of the thrusters even if made up of deep cycle batteries.

You may be right about the potential of a failed battery. I will to research how to figure out if that is the case.

Since it has run for years you should be looking for what changed causing it to quit, not looking at faults in the original installation.

The Duo Charge manual says the input and output wires are both 10 gauge with 30 amp fuses. All fuses blow after a duration of time at a particular amperage. If your Duo Charger has been running for extended periods at exactly 30 amps the fuse may not have blown, but the element is running at a temperature just below it’s melting point, and the clips in the fuse holder will be at the same temperature, oxidizing and loosing their tension. The result is increased resistance in the junction with the fuse terminals, causing additional heat and the 30 amp fuse overheats and blows at an amperage below 30. The fix would be to replace the fuse holder.

While it violates my “ look for why changed” advice, this may be worth a quick look. The Balmar manual says that the input wire should be short, no longer than the supplied pigtail and the output wire should be 10 gauge, and a minimum of 8 feet long beyond the supplied pigtail. From their description it appears they use the resistance of the output wire as part of their regulation scheme. Quote from the manual: “the reason for the extra wire length is to act like an electric spring which allows the Digital Duo Charge to produce a higher current.” Do you have this length of 10 gauge wire? Since it has run for years I assume so, but worth checking, and adding length if needed.

Your point about asking for what has changed is a good one, and goes along with Ted’s question about a possible failure of the battery. I also like the idea of just aging connections at the fuse holder that could have increased the heat. The fuse holder definitely looks like got overheated.

I don’t believe the installation has that 10 gage wire. The supplied wire is connected to a buss bar which connects to the battery via a 4/0 battery cable. That runs probably 8’ to the battery. So the original installation doesn’t seem to conform to the Balmar installations.

Even so, it has worked for a number of years with no APPARENT problems. I still think that in some ways, that the design which causes the Balmar to shut down if there is too large a voltage delta between the house and charged bank poses some potential problems in this application.

If the current batteries are sound, then I think reconfiguring to use an ACR would be my best option as I have the ACR. If the batteries are not sound, then I am very tempted to simply upsize my house bank and run the thrusters and windlass off the house bank. Since all my primary charge sources run to the house bank, the alternator is charging it while using the thrusters or windlass as well.

That gets back to how to determine if the batteries that are there are OK?

 

[JDCAVE]

Dave: I had a similar issue with a blown fuse on my DDC, which I reported here:

http://www.trawlerforum.com/forums/...-duo-charge-charging-thruster-bank-33225.html

I never fully solved the issue and replacing the charge source is on the “to do” list. I only had 20 amp fuses aboard and it limped along as a charger but the thruster could not be used. I replaced the fuse with a 30 amp one and the issue has not returned, but I agree with others here that it is not the best method of charging my thruster bank. I think it becomes more of an issue when your batteries are nearing end-of-life.

I am leaning towards moving the Mastervolt battery mate charge from the Genny battery to the thruster bank, as that unit can provide more amperage when required. The issue will be charging demands when the thruster is actuated, voltage drops, wire size, appropriate negative termination, etc. I’m going to have my electrician look at this because he installed the Mastervolt unit.

You may want to look into the option of using a Mastervolt Batterymate. It may, or may not be a better option than either the ACR or Duo charge.

Jim

 

[Aquabelle]

Ted, I know there is a lot of discussion of start vs deep cycle for thruster batteries. If someone had a remote batter in the bow next to the bow thruster, then a start battery(s) would make some sense. In my case, I have one bank that supplies both thrusters and the windlass. The PO chose Lifeline 8Ds. I am sure the reason he made that selection was that is what the yard that did the work recommended and supplied. My understanding is that those batteries are kind of a hybrid. Not a bad choice really. If the bank is sufficiently large, it can provide the high, short term demand of the thrusters even if made up of deep cycle batteries.

You may be right about the potential of a failed battery. I will to research how to figure out if that is the case.




Your point about asking for what has changed is a good one, and goes along with Ted’s question about a possible failure of the battery. I also like the idea of just aging connections at the fuse holder that could have increased the heat. The fuse holder definitely looks like got overheated.

I don’t believe the installation has that 10 gage wire. The supplied wire is connected to a buss bar which connects to the battery via a 4/0 battery cable. That runs probably 8’ to the battery. So the original installation doesn’t seem to conform to the Balmar installations.

Even so, it has worked for a number of years with no APPARENT problems. I still think that in some ways, that the design which causes the Balmar to shut down if there is too large a voltage delta between the house and charged bank poses some potential problems in this application.

If the current batteries are sound, then I think reconfiguring to use an ACR would be my best option as I have the ACR. If the batteries are not sound, then I am very tempted to simply upsize my house bank and run the thrusters and windlass off the house bank. Since all my primary charge sources run to the house bank, the alternator is charging it while using the thrusters or windlass as well.

That gets back to how to determine if the batteries that are there are OK?

The benefit of the DDC over an ACR is that it permits the use of a different battery chemistry for Start/cranking purposes. In my case, I have Crown FLA 6v gc's for House and 3 x Optima spiral wound AGMs for Cranking (Start, Thruster, Davit & Windlass). Works perfectly and Cranking bank still in fine form after 9 years (hoping for 11).

 

[dhays]

Dave: I had a similar issue with a blown fuse on my DDC, which I reported here:

http://www.trawlerforum.com/forums/...-duo-charge-charging-thruster-bank-33225.html

I never fully solved the issue and replacing the charge source is on the “to do” list. I only had 20 amp fuses aboard and it limped along as a charger but the thruster could not be used. I replaced the fuse with a 30 amp one and the issue has not returned, but I agree with others here that it is not the best method of charging my thruster bank. I think it becomes more of an issue when your batteries are nearing end-of-life.

I am leaning towards moving the Mastervolt battery mate charge from the Genny battery to the thruster bank, as that unit can provide more amperage when required. The issue will be charging demands when the thruster is actuated, voltage drops, wire size, appropriate negative termination, etc. I’m going to have my electrician look at this because he installed the Mastervolt unit.

You may want to look into the option of using a Mastervolt Batterymate. It may, or may not be a better option than either the ACR or Duo charge.

Jim

I'll try and check that out and add that to my list of potential long term solutions.

 

[dhays]

The benefit of the DDC over an ACR is that it permits the use of a different battery chemistry for Start/cranking purposes. In my case, I have Crown FLA 6v gc's for House and 3 x Optima spiral wound AGMs for Cranking (Start, Thruster, Davit & Windlass). Works perfectly and Cranking bank still in fine form after 9 years (hoping for 11).

Exactly. Initially the boat had sealed FLA batteries. He ended up replacing the engine start battery, genset start battery, as well as the thruster bank with AGMs. Since they had different charging profiles, than the FLA house bank, that may be why whomever did the work elected to go with the Balmar Duo Charge.


Now, I have AGM throughout and so don't have that issue.

 

[cardude01]

Random interjection, because that’s what I do:

I have a Balmar Duo Charge, but I don’t know why. It came with the boat.

My thruster works off the house bank. I have a separate start battery. All batteries are AGM. I have a 100amp Balmar alternator. What does this Duo Charge do?

(Now back to Dhays original problem)

 

[dhays]

Random interjection, because that’s what I do:

I have a Balmar Duo Charge, but I don’t know why. It came with the boat.

My thruster works off the house bank. I have a separate start battery. All batteries are AGM. I have a 100amp Balmar alternator. What does this Duo Charge do?

(Now back to Dhays original problem)

We can only guess. If it isn’t connected, then it isn’t doing anything. ;-)

My guess would be that your charging sources go to the house bank. The Duo Charge then charges your start battery from the house bank. When there is a charge current to the house bank that raises the voltage above a given threshold (I don’t remember what that is) then the Duo Charge will send up to 30 amps of charging current to your start battery.

This keeps your start battery charged up.

It should be easy to tell. There are two fused wires on the Duo Charge. One will go to the house bank and the other to the battery that is being charged by it.

 

[cardude01]

Ahh yeah that makes sense. I guess the duo charge sends the most current from the alternator to the bank with the lowest voltage first or something like that.

Dhays, with the addition of solar do these fancy switches become a little less important? For instance, underway on a sunny day my solar is charging up the house bank so the alternator doesn’t have to do much other than keep the start battery topped up.

 

[CMS]

The Duo Charger can output a maximum current of about 29.9A. It is shipped with a 30A fuse. Fuses should not be run at or even near 100% of the fuses rating for long periods of time or they will eventually nuisance trip.

The fuse is there to protect the wire not the DDC. For ABYC purposes 10AWG 105C wire has a max ampacity of 60A outside an engine space and about 51A inside an engine space.

A 40A fuse is a much better choice if your DDC is bouncing off its max rating on a routine basis and will minimize the risk of nuisance trips..

Alternatively you can source a suitably sized contactor/relay/solenoid and run the DDC in manual combine mode when current expectations exceed the 30A limit. Once current is below the 30A threshold the toggle switch can be turned off and the DDC will resume operation as it normally does. The solenoid drive circuit is designed for larger loads such as a thruster bank.

That said an ML-ACR, and appropriate gauge wire, or a Sterling Power BB1230 or BB1260 would be a better approach if 30A+ is required. Unlike the DDC the Sterling Power BB1230 won't turn off if 30A+ demand is on the load side.

 

[diver dave]

.. It had gotten so hot in the process that I'm not sure I trust the fuse holder anymore.


So I have two questions. The first is why would the fuse blow? Did the Duo Charge fail to shut itself down if the thruster bank asked for more than its 30 amps?

If you see evidence of heat damage, I do not suspect an overcurrent event caused this issue. Fuses do blow due to local heat buildup because of bad crimps, bad fuseholder design or corrosion, or loose connections.
Do you have a pix of the fuseholder arrangement?

 

[JDCAVE]

The Duo Charger can output a maximum current of about 29.9A. It is shipped with a 30A fuse. Fuses should not be run at or even near 100% of the fuses rating for long periods of time or they will eventually nuisance trip.

The fuse is there to protect the wire not the DDC. For ABYC purposes 10AWG 105C wire has a max ampacity of 60A outside an engine space and about 51A inside an engine space.

A 40A fuse is a much better choice if your DDC is bouncing off its max rating on a routine basis and will minimize the risk of nuisance trips...

Ahhhh! Thanks for this CMS! That explains my particular situation exactly. I will obtain a 40 amp fuse.

 

[dhays]

The Duo Charger can output a maximum current of about 29.9A. It is shipped with a 30A fuse. Fuses should not be run at or even near 100% of the fuses rating for long periods of time or they will eventually nuisance trip.

The fuse is there to protect the wire not the DDC. For ABYC purposes 10AWG 105C wire has a max ampacity of 60A outside an engine space and about 51A inside an engine space.

A 40A fuse is a much better choice if your DDC is bouncing off its max rating on a routine basis and will minimize the risk of nuisance trips..

That said an ML-ACR, and appropriate gauge wire, or a Sterling Power BB1230 or BB1260 would be a better approach if 30A+ is required. Unlike the DDC the Sterling Power BB1230 won't turn off if 30A+ demand is on the load side.

Thanks Rod. The Sterling does sound like a better DC to DC charger for a large bank. I have an ML-ACR available and I think some appropriate cable. I'll see if I can setup that at least to get me back up and running. Then I need to figure out if the batteries are still good.

 

[dhays]

If you see evidence of heat damage, I do not suspect an overcurrent event caused this issue. Fuses do blow due to local heat buildup because of bad crimps, bad fuseholder design or corrosion, or loose connections.
Do you have a pix of the fuseholder arrangement?

I'll be at the boat tomorrow so I'll see if I can get a decent photo of it. The Fuse holder is a decent design that is sealed. While possible, I have a hard time imagining that it would have oxidized. However, the look of the fuse and the holder does imply heat to me so you never know.

 

[JDCAVE]

Dave: is your windless 12 or 24 V?

 

[Aquabelle]

Good stuff from Rod as always and I will swap to a 40A fuse myself. Actually 30A going into a Start bank is a lot in 90% of cases. I think the OP should check individual batteries....one may have failed and be causing a problem that would affect any charging solution.

 

[dhays]

Dave: is your windless 12 or 24 V?

12v

 

[dhays]

Good stuff from Rod as always and I will swap to a 40A fuse myself. Actually 30A going into a Start bank is a lot in 90% of cases. I think the OP should check individual batteries....one may have failed and be causing a problem that would affect any charging solution.

Yes, think that is a great idea. I just need to figure out how to check the batteries.... If they were wet cells my hydrometer (sp) would work, but I haven't had wet cells now in a few years.