Question On Battery Charging

[Scott T-Bird]

The APD is a more economical choice than going with a more expensive Victron based system.

I chose Scenario 2 for my cruising using an APD with the Balmar 618 Regulator and a 165a Balmar regulator. This was the state of the art in 2020 when I upgraded my batteries. If I was doing the upgrade today, I would get a Zeus Regulator and Alternator and with Victron Cerbo monitoring and communication system. And that is something we haven't talked about yet, the monitoring system. It is as or more important than any other part of the electrical system.

A question for @GeneraiT001, what are your cruising plans now? Still crossing the Atlantic to the Med? Or Down the coast to Panama and up to BC?

What do you mean by the "more expensive Victron based system"? Are you talking about the Victron DC-DC charger or something else?

I, too, have the Balmar 618 regulator paired with an old 125a alternator that I am thinking about replacing. My first thought is that I want to buy a Balmar XT alternator (keeping the old alternator as a spare) but I don't want to buy a new regulator. When I want to upgrade with LiFePo batts, I'll need to buy a DC/DC charger to replace the ACR that I currently use. Currently, I have to two AGM battery banks, which includes a very new AGM 100ah "start" battery that I won't replace. So it appears from the advert that the Victron DC/Dc charger provides the spike protection that we are talking about (scenerio 2). Since I need the DC/DC charger anyway, i'm not sure I understand how the "more expensive Victron" can be substituted by a cheaper APD.

 

[dlochner]

What do you mean by the "more expensive Victron based system"? Are you talking about the Victron DC-DC charger or something else?

I, too, have the Balmar 618 regulator paired with an old 125a alternator that I am thinking about replacing. My first thought is that I want to buy a Balmar XT alternator (keeping the old alternator as a spare) but I don't want to buy a new regulator. When I want to upgrade with LiFePo batts, I'll need to buy a DC/DC charger to replace the ACR that I currently use. Currently, I have to two AGM battery banks, which includes a very new AGM 100ah "start" battery that I won't replace. So it appears from the advert that the Victron DC/Dc charger provides the spike protection that we are talking about (scenerio 2). Since I need the DC/DC charger anyway, i'm not sure I understand how the "more expensive Victron" can be substituted by a cheaper APD.

The Victron Cerbo GX provides very detailed monitoring of the electrical system and when combined with a Victron BMS and a Wakespeed or Zeus regulator the alternator is well protected as the BMS will send a signal to the regulator that it is about to shut down. When the regulator receives this signal it cuts the field current which prevents the alternator from producing current thus preventing the voltage spike that destroys the diodes and rectifiers in the alternator. There are other benefits to this system including the ability to regulate alternator output based on engine RPM and amperage bases charge monitoring instead of voltage and time based charging. For most of us this is more than we need for weekend cruising and summer vacation cruising. I spent 2 years living aboard with the Balmar system and it worked well enough with both LA and LFP batteries for less money than the Victron system. If I were to cross oceans and spend lots of time in remote areas I would upgrade to the Victron/Zeus system.

 

[Scott T-Bird]

The Victron Cerbo GX provides very detailed monitoring of the electrical system and when combined with a Victron BMS and a Wakespeed or Zeus regulator the alternator is well protected as the BMS will send a signal to the regulator that it is about to shut down.

Generally, I favor upgrading to more sophisticated systems, especially in electronics. However, it seems that it is increasingly difficult to keep up with the continuous sophistication and to what end? Why purchase an external BMS when the better brands include BMS in the battery? Why the need for a central hub when the battery monitor and external regulator already performs all the functions. Why the need for a central hub to monitor and customize when we generally "set it & forget it" anyway? It seems like the system is over-redundant and unnecessary. I get it that when your home is on the water, there is a need for more sophisticated systems, but it also appears that the attraction is more about the sophistication rather than enjoyment of all the reasons sailors like to experience the outdoors from their boats. It's almost a contradiction to create so much emphasis on monitoring the health and customizing settings at the expense of spending more time swimming, hiking, diving, biking, sightseeing, shopping, eating, visiting, etc!

 

[Scott T-Bird]

Boiling it down to this thread in particular ... if the new batteries come with BMS built in (as the better brands seem to do) and the biggest concern is frying the alternator diodes under the preferred scenerio 2 while using a DC/DC charger going thru the LiFePo batts first. If you purchase a DC/DC charger that features that protection (as indicated by the Victron DC/DC product) and you install an APD for redundancy, why would there be any desire to purchase a Cerbo central hub and external BMS?

 

[dlochner]

If you purchase a DC/DC charger that features that protection (as indicated by the Victron DC/DC product) and you install an APD for redundancy, why would there be any desire to purchase a Cerbo central hub and external BMS?

The higher end brands like Lithionics and Victron do not come with an internal BMS. The big advantage to the Cerbo is having all the information in one place. Our boat needs 3 different apps to monitor the electrical system, one for the alternator, one for the solar panels, and one for the batteries. It is attractive to have all that information in one place that can be easily seen.

My experience with the Balmar SG 200 was great when I had LA batteries, however, once I switched over to LFP batteries the SOC reading was seldom accurate. I wasn't able to figure that out, so it was necessary to have the battery specific app.

Then, the battery manufacturer dropped its support of the batteries I had and the app was withdrawn from the App Stores. No problem until I upgraded my phone and the app was no longer available. As a result I lost track of the batteries SOC and they ended up deader than a doornail. Fortunately I was able to find a source for the app, but loading it onto my iPhone was a daunting task and I gave up and bought a cheap Android tablet and loaded the app. Fortunately again, about the time all this happen MaineSail posted a video on how to resurrect dead LFP batteries that won't take a charge.

The batteries are Kilovault made by Top Brand a Chinese company and sold by AltE a reputable alternative energy store. Both Panbo and MaineSail had recommended Kilovault batteries, so I was comfortable purchasing them. Had I had a better monitoring system, I might have avoided some of the frustration with finding my batteries dead.

Then there was the alternator. After having a yard do some simple work on the engine the alternator was fried. The alternator temp sensor was damaged and the alternator overheated. Had I had a better monitoring system, I might have caught the trouble long before the damage was done.

 

[CrispyCringle]

I recently switched to lithium with the associated electrical changes. I resisted getting a Cerbo at first. But I dont regret it at all. Some like to tinker and control, some dont. Once everything is set up, its not like it needs to be changed all the time. But the Cerbo is just an amazing piece of equipment.

One of the best features of the Cerbo is its coordination among charge sources. I have the inverter/charger, solar, and B to B. One app to monitors and controls the charging, so I never get one in bulk charge and another trying to go to absorption. I can monitor via the internet when away, app available on the chartplotter, yada, yada. But some prefer wooden boats and sextants. I get it. Its all good IMO.

 

[Scott T-Bird]

I just watched a video that reminded me that not all BMS is the same. Apparently, BMS within the battery case may just have a simple open/closed circuit that shuts down acceptance suddenly when the battery is fully charged, which can lead to the alternator crashing. An external BMS, as advertised by Victron, should communicate with the external alternator regulator to enable a soft landing and that is a significant distinction. This has probably been discussed numerous times within this forum but has taken a while for it to sink in to me!

However, I still question if the Victron DC/DC charger provides the protection that we are talking about in this thread. It appears to me that they advertise that it does.

 

[CrispyCringle]

However, I still question if the Victron DC/DC charger provides the protection that we are talking about in this thread. It appears to me that they advertise that it does.

Im not aware of any built in protection for BMS cutoff with the Victron DC/DC chargers. I think what being discussed is the fact that the lithium is being charged indirectly by the alternator through the DC/DC charger and lead battery, and that that setup inherently isolates the alternator from whatever the BMS is doing. A BMS voltage cutoff will not slam the alternator diodes with this type of setup. The DC/DC charger doesnt care, and the lead battery acts as a kind of accumulator (cushion).

 

[Scott T-Bird]

Im not aware of any built in protection for BMS cutoff with the Victron DC/DC chargers. I think what being discussed is the fact that the lithium is being charged indirectly by the alternator through the DC/DC charger and lead battery, and that that setup inherently isolates the alternator from whatever the BMS is doing. A BMS voltage cutoff will not slam the alternator diodes with this type of setup. The DC/DC charger doesnt care, and the lead battery acts as a kind of accumulator (cushion).

Well, we have been discussing the difference between charging the lithium house bank thru the AGM start battery and charging the start battery thru the lithium bank as can be done either way thru a DC/DC charger. I think the general consensus is that it is more efficient to run alternator output thru the lithium bank and charge the AGM batt via the DC/DC charger. But it is also riskier to do it this way.

That's when I looked this up:

Battery charging & power conversion | Victron Energy

Fast-charge battery banks or power any AC/DC load worry-free. From RVs to marine and industrial uses, our products cover every charging and conversion need.

www.victronenergy.com

What caught my eye was this: "DC-DC chargers increase battery life by adding sophisticated charging features to safely and efficiently charge any battery. Controlled charging will also protect alternators in lithium systems, preventing alternator and battery overload".

But reading this again, I see that they may not mean that the charger protects the alternator. They may be describing the "system" that protects the alternator. I didn't catch that before because the statement was included in the DC/DC charger advertisement. Now, I suspect that this statement insinuates that the charger must be part of a system to protect the alternator. That seems to provide further argument that the external BMS is necessary and perhaps the monitoring system as well.

I get frustrated by the lack of information provided by the manufacturer. I suppose it encourages people to hire electronics experts rather than diy with these critical elements.

 

[Hello Below]

I'm guessing the more prudent scenario is scenario #1...but it seems like you cannot take full advantage of that high output alternator via a DC-DC charger in that setup? Hopefully I'm wrong (again)

I expect a 2nd DC-DC charger in parallel would relieve the bottleneck, solve this problem and provide redundancy?

 

[dlochner]

What caught my eye was this: "DC-DC chargers increase battery life by adding sophisticated charging features to safely and efficiently charge any battery. Controlled charging will also protect alternators in lithium systems, preventing alternator and battery overload".

In the second sentence "controlled charging" refers to the practice of controlled charging rather than the specific DC-DC charger. I lost an alternator because the temp sensor was damaged which led to uncontrolled charging, specifically the alternator over heated.

For clarification, I know the Victron external BMS has the ability to signal the regulator to cut the field when it is about to shut down charging that is not to say there are no batteries with an internal regulator that can signal the alternator of an impending shut down. If those batteries exist, they will not be the cheapest on the market.

 

[Hello Below]

Here is a link discussing the paralleled chargers and some cautionary words to take when using with a Victron Cerbo GX.

Dual Victron Orion XS - DC to DC Battery Chargers