Victron DC to DC Charger install

[jkidd]

Jody, Sounds like a well designed and valid experiment. You mentioned you were going to monitor the heat of the "charging coils". Hopefully this will be easy to do. I believe it is essential in the experiment.

The start requirement for the Suzuki 115 is 512 amps CCA. The usual start current draw for this engine max Is in the 150 amp range. I believe the shunt should handle this easily. You could put the clamp on meter over the start cable and see what it draws.

Another depth to the experiment--and it may put more load on the outboard charging circuit, is to draw down the starting battery to 50% (resting voltage of 12.2) and then measure current from outboard charger circuit with and without the DC to DC charger.

I suspect that the start battery acts as sort of a "buffer" for the outboard charging circuit, if the Victorn acts like the Sterling which I have.

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Well the charge coil is under a cast iron fly wheel, but if I stop the motor I should be able to get a temperature from the bottom. I went hunting for all my clamp on meters and there all AC. I do have a couple of shunts laying around and with the blue tooth dongle will give me more info faster by just being able to do a screen shot.

Normally my start battery wouldn't be discharged as it only starts the motor and is used for the bilge pump. I could see that it might be good information to know how things might react under those conditions so I think I'll give it a try.

I think your right about the battery buffering what is going on, the test should prove that or I'll have to switch to the 18 amp DC to DC charger.

 

[thataway]

We are planning to use this boat primarily for boondocking in the PNW. We may go days without starting the outboard and will have refrigerator, freezer, lighting, computers, etc. to power. We have spent many years boondocking in an RV, but we relied upon propane for refrigeration and won't be doing that with the boat. We'll have solar, but may have days of rain to contend with. I want the increased energy storage capacity and light weight of LiFePO4.

That certainly qualifies for the li batteries. But of course the solar is a problem from several issues in the PNW--not only over cast, but sun angle. offset somewhat by longer light days. Chech out the various types of solar panels, and series vs parallel. I suspect you may need in the 400 watt area to keep up with refrigerator freezer chest times in the PNW... It may be do-able, but you can buy a lot of gasoline for the $5,000+ the Li battery, solar, special chargers are going to cost.

Keep us in the loop, it will be an interesting project!

We rarely stayed more than one day at any one place, with the exception of a few Marinas in the PNW--during the 4 years we were cruising there from April thru Oct, Of course back then we only had FLA batteries. (I had put a true gel cell in my RV--and it was fine as long as I owned the RV, and only charged it thru the specific charger profiled for gel batteries. The fellow I sold the RV two fired the gel cell the first time he used it--turned the switch which combined with state batteries, despite my warning and a table on the switch. The higher voltage from his alternator killed in it about 4 hours...

 

[pcg]

I suspect you may need in the 400 watt area to keep up with refrigerator freezer chest times in the PNW...

Yes, that's pretty much the ball park number I'm thinking as well.

...you can buy a lot of gasoline for the $5,000+ the Li battery, solar, special chargers are going to cost.

True, but we can only carry about $150 worth at a time and we don't want to have to make a long trip back down an inlet to find a marina and then have to travel all the way back again, plus we like quiet, and detest the sound gasoline makes when we convert it to electricity.

Keep us in the loop, it will be an interesting project!

I will. I value the expertise of folks here, yours especially. It will be a long loop. I am just now starting to see the light at the end of the tunnel filled with other projects I have to finish first. I have to finish those so I can make room for the boat in my shop. Hopefully I can start doing fiberglass work next fall.

 

[thataway]

With a high output battery charger there is very little run time to charge Li batteries. Charging at 100 amps for example.

Thanks for the thoughts.

 

[robhwa]

Rob,
I'd really like to see photos of your 525watt solar array, I imagine on a summer sunny day it does a good job of charging your batteries. If no photos, where do you have them mounted? How many LiFeP04 batteries do you have and how many Ah? I assume you need the 24v system for your trolling motors?

Problemadela (my CD22) is inside now, and panels, batteries, and a few electronics moved to my camper for a winter trip to SW. Here is what I plan for when I return.

I have three 175 watt flexible panels that I bungee to the rooftop handles (easy on, easy off, just a few pounds each), put into cable combiners (3 into 1) and then run a single + and - 8 gauge cable through the roof into the cabin and into the charge controller. I don't drive with the boat on the trailer with the panels on. I use these same panels on my camper, held on by bolts glued to wingnut them to. Same entrance with the 3 combiners. Often, I remove the panels and hide under the overcab bed, and usually take them off when I drive really fast since the truck alternator charges things quickly.

The main addition I haven't tried is the 12 to 24 volt converter to power my trolling motors. I just ordered it. With 50 amps, 24 volts (1200 watts nominal) I won't be able to run both 80 lb motors at full throttle at the same time, but I never do anyway.

 

[thataway]

Rob,
What is the battery charging capacity of the Renology 1000 watt inverter/ charger?

The one I found was only 30 amps and there were a fair number of low ratings on amazon. Is there a different model which has higher output and better ratings?

Also how are you approaching the over heating of the flexible solar panels when laid on a surface without ventilation beneath them?

What is your real life experience with the output of the three, 175 watt solar panels? (I think you have a Victron 712 in the system?-I didn't see it in the diagram)...

Are you only relying on the engine to charge the engine start battery?

Thanks

 

[robhwa]

Rob,
What is the battery charging capacity of the Renology 1000 watt inverter/ charger?

The one I found was only 30 amps and there were a fair number of low ratings on amazon. Is there a different model which has higher output and better ratings?

Also how are you approaching the over heating of the flexible solar panels when laid on a surface without ventilation beneath them?

What is your real life experience with the output of the three, 175 watt solar panels? (I think you have a Victron 712 in the system?-I didn't see it in the diagram)...

Are you only relying on the engine to charge the engine start battery?

Thanks

Inverter-Charger: Renogy inverter/charger/transfer switch 1000 is 30 amps, 2000 is 65 amps. All 12 volts. These things are big and heavy, the 2000 is 51 lbs. However, you get an inverter AND a 120 volt charger with an internal transfer switch. I'm not sure I need 65 amps for my plans. I have a 2000 in my house through a panel transfer switch. Been testing, and works fine so far, charging at rated (>60 amps) and can put out steady 2000 watts, and a lot more for a few seconds. I plan to test this in the CD22 this Spring/Summer and see if I like it. All of these electronics will reside inside the galley cabinet.

Overheating Panels: I haven't had a lot of problem with overheating of solar panels. They do get hot. Reading earlier about flexible panels glued to roofs, I anticipated the problem which is one reason I didn't glue them, and had planned to slip 3/4 x 3/4" wood strips under during intense days to provide airflow on the backside of the panels. Not needed, but we'll see with the SW trip.

Diagram I Posted: Let me review, this diagram I posted would create a turn-key system, and I will install this spring/summer. Testing most of it in my camper now.

Earlier, I had a hodge-podge. 175 watt panels bungied on roof, charge controller BZ MPPT500, feeding into a two series-wired AGM Group 31 for a 24-volt system. Battery charging through TrollBridge 12x24 and generator or shore charging with a 40 amp Cabelas charger. All bases covered, but what a mess, and poor charging from the Honda 90! Simply going from the two AGM to two Lithium should reduce 60 lbs and give me more useful power and faster charging when available. Testing in the camper confirms this...I believe my only weak link will be the 17 amps of charging from the Honda 90. Overall weight will be reduced.

One advantage of the new system is that the starting battery will also be charged by the large solar panels, not just the main motor alternator. I already had a 5 watt "maintainer" panel hooked to the starter battery, and experienced full charge almost all of the time. I really liked the TrollBridge, but can't use with Li batteries, and it won't be needed. If proposed turnkey system doesn't work, I'll fall back to this default system on the C-Dory and keep the other in the camper where I don't need 24 VDC.

Panel performance: So far, so good. Back in July, when we had sun, the panels would often output well, sometimes at 30 amps, 20 volts. Usually, that was full sun with a cool breeze. Output goes down as they heat up. If I go back to a 24 volt system, I may try and add more panels. Hope this helps!

 

[jkidd]

I started my test this afternoon I took my house battery down to 85 percent and ran the motor at 950 rpms to charge it back up. Next picture is the house battery status.



Next Picture is the start battery status.



Next picture is the DC to DC charger status in Bulk mode.



It took roughly 6 minutes to switch from bulk to absorption mode.









I took temperatures of the charge coil during the test the highest reading was 130 degrees F. this was right at the end of the bulk mode. More to come later.

 

[thataway]

Jody were these the LI or lead acid batteries?

 

[jkidd]

Both batteries are Agm. I have the new Battleborn sitting in the kitchen haven’t installed it yet.

 

[jkidd]

The next series of photos take you through the state of charge with the voltage and current readings.











I started the test at 3:24 pm and finished at 5:07 pm and reached a float charge at 5:06 pm.

In looking at the numbers I wouldn't spend the extra money to get the 30 amp charger and would just use the 18 amp charger instead. I am going to leave the 30 amp installed in mine.

 

[smckean (Tosca)]

In looking at the numbers I wouldn't spend the extra money to get the 30 amp charger and would just use the 18 amp charger instead.

A few years ago I purchased and installed a quality ProMarine 36amp charger. It has 2 outputs, but will put all 36 amps into only 1 output if the other battery is fully charged. I was disappointed that the charger has never outputted more than 20 amps to the house batteries. I finally decided that how many amps a charger feeds to a depleted battery depends on that battery's state of charge (SOC). Since none of us take our batteries down below about 50% SOC (I'm talking lead/acid to AGM here), I'm assuming full charger output is never used.

What I've never figured out is whether that state of affairs (assuming I'm even correct in my analysis) depends on the charger or the battery. That is, if for example, my 36 amp charger outputs 20 amps in a given situation, would a 20 amp charger also put out 20 amps in that same situation, or would the output scale with the charger's maximum output (i.e., the 20 amp charger might only output say 13 amps).

Anyone know the answer?

 

[robhwa]

In looking at the numbers I wouldn't spend the extra money to get the 30 amp charger and would just use the 18 amp charger instead.

A few years ago I purchased and installed a quality ProMarine 36amp charger. It has 2 outputs, but will put all 36 amps into only 1 output if the other battery is fully charged. I was disappointed that the charger has never outputted more than 20 amps to the house batteries. I finally decided that how many amps a charger feeds to a depleted battery depends on that battery's state of charge (SOC). Since none of us take our batteries down below about 50% SOC (I'm talking lead/acid to AGM here), I'm assuming full charger output is never used.

What I've never figured out is whether that state of affairs (assuming I'm even correct in my analysis) depends on the charger or the battery. That is, if for example, my 36 amp charger outputs 20 amps in a given situation, would a 20 amp charger also put out 20 amps in that same situation, or would the output scale with the charger's maximum output (i.e., the 20 amp charger might only output say 13 amps).

Anyone know the answer?

Chargers. How many amps flows into a charging battery can be a mystery. The charger is part of the process, but only part. The battery must ACCEPT amps from the charger as well. In my measurements, a single FLA never accepted 36 amps at 50% charge or more. I never wanted to damage my FLAs so I didn't draw below 50% SOC. When I have drawn down to 50% SOC and monitored charging acceptance, it seems that the online rule of 25% or 0.25 for FLA works reasonably well, so only 25A max for a single 100A FLA even with an infinite charger due to internal resistance that increases with SOC. That means (in theory) you would need at least two FLA to accept your full 36A. Also, claims from chargers may be like claims from FLA batteries....you won't get 100AH out of a 100AH battery and you probably won't get stated amps out of a charger.

Cables. Cables are another factor. You can lose a lot of amps as heat from cables that can't handle the load (i.e. long runs of even fairly large cables) through voltage drop. You may not notice it at all unless you measure voltage at both ends or it is really bad and cables get hot. Mostly the heat just dissipates. I generally don't use the cables supplied with a system, as they are usually not adequate for the task. Buy large cables, get a crimper, and make the runs as short as possible.

Batteries. LiFePO4 are a different horse. In my measurements, they can take a lot of Amps. BattleBorn's BMS, for instance, doesn't limit charging amps, but recommends 0.5 (50A) for charging, and states that it can take 100A for short periods. Hooking a large (i.e. >200AH) system to a truck alternator with cabling sufficient to handle extremely large AH is a recipe for ruining your alternator, particularly large loads with the vehicle not moving so air isn't cooling it. This is generally not an issue with FLAs because of internal resistance limiting current flow.

I don't think the alternators used in most motors with C-Dorys will have Amps high enough to be an issue. My Honda 90 only offers a max of 17 amps, and the newer ones only about 35 amps.

 

[jkidd]

I have the LI battery installed for the house in the port lazarette and the dc to dc charger in the same space. I wanted to keep the wires as short as possible. So far these are the advantage’s that I am seeing.

Battery weighs 29 lbs the AGM battery weighs 78 lbs for a savings of 49 lbs.
If there were 2 house batteries I would save 120 lbs for the same capacity.
I can now use nearly 100 percent of the rated capacity instead the 50 percent of lead acid.
The LI battery does not need to be charged back up to 100 percent within 24 hours like lead acid.
The LI battery likes to be kept between 30 to 90 percent with no ill effects.
I can run multiple days without charging and use the capacity of the battery if I like.
I can disable the dc to dc charger if the LI battery doesn’t need charging.
Don’t have to worry about over charging the house battery when batteries are combined.
The LI battery life is 3000 to 5000 cycles 4 to5 times the life of lead acid.

I will be doing the same charge test that I did with the AGM house battery to see the results.
While this is pricey up front over time it will pay for itself might not have to buy another house battery for 15 years or more and if I buy a new boat I can move that battery to the new one.

 

[croakz]

@jkidd You mentioned you'd go for the 18a over the 30a if you were doing it again, was that due to what your outboard realistically puts out?

I have a new Honda BF100 and I'm trying to decide whether to go with a Victron 18a or 30a. Thanks.

 

[jkidd]

It looks like Victron has stopped marketing the 18 amp charger and only have the 30 amp. what I saw with the 30 was it would cycle on and off till it reached absorption mode. I have since installed the 18 amp. It might be possible to limit the current but I haven't tried that.