Alternator charger with lithium batteries

[Diesel Pro]

I have a MK3 DC alternator charger on my boat. I recently switched to Ionic lithium starting and troling and can see the charge rate on the app. I can see the starting battery run as high as 40+ amps depending on SOC and engine speed. Problem is the alternator charger only ever does 2-4 amps according to the BMS of the trolling batteries. Before I dive into troubleshooting this I figured I would see if anyone else has run these and has any ideas? My initial thought was that that there was no charge profile and that it just connected the batteries more or less, but I'm guessing that there may well be a profile that sees the lithium voltage and thinks there is no need to ramp up the output? Wanting to see what I can figure out before considering the Yandina module.

[Ann-Marie]

The numbers could be correct and a Yandina module would not change anything. Charging systems are designed to put amps into a battery while simultaneously avoiding going over voltage. Smart chargers can use a high voltage, 48 volts for example, to force current in rapidly while monitoring the battery voltage to see if it is safe. As the smart charger sees the voltage getting to the limit it then reduces the current with electronic controls and tapers off to zero current. While the battery voltage is still safe, the voltage available to force charge in is, for example, 48 - 14 = 34 volts.

Dumb chargers don't have the smarts to be able to control a higher voltage source so for safety they use a "safe" source voltage, typically about 14 to 15 volts. So the voltage available to force current into the battery towards the end of charge is only 15 - 14 = 1 volt. This will still eventually still charge the battery but take much longer in order to remain safe.

With a lead acid battery doing most of its bulk charging between 12.5 and 13.5 a dumb charger has voltage available to force in current and give you the 40 amp readings. But a Lithium battery doesn't even start to charge until the voltage is around 13.5 and at this voltage a dumb charger is already running out of volts.

This is a simplification of the situation and ignores many parameters but its the basic difference between smart and dumb chargers.

[Diesel Pro]

All fuses and connections checked out good. Trolling battery voltage is 13.2v on the Ionic APP. Variable response, but typically I see battery 1 will accept around 3-4 amps on the BMS. Battery 3 was same and battery 2 was 0.0. I did not try switching leads yet to see if it follows the battery or the circuit. If I added enough charger voltage to the starting battery I could get #2 to start showing that it was accepting charge but again only 3 amps or so. DC Charger output leads measured 14+v when disconnected as I recall. It shows the amperage out which also would include power to the Merc when key is on engine off.

For reference MK460 charger throws 13-14 amps on the trolling batteries no problem.

I think I need to check my feed wire to teh charger. It's #12 duplex and I'm certain that I soldered the connections though...

[Diesel Pro]

Ann-Marie,

What triggers the Yandina? Looks like it's always connected? No issues with running down the starting battery?

[Team Dougherty]

Is that charger setup for lithium batteries? Lithium batteries have a higher voltage then regular lead acid batteries. The voltage of the lithium trolling batteries maybe at a level that the charger thinks they are charged and will not sent power to them to charge them

Also, a lithium battery has a lower internal resistance then regular lead acid batteries. That 40 amps going to your starting battery may cook your alternator in short order. A regular alternator with it voltage regulator are not designed for lithium batteries.

[Diesel Pro]

I don't know that the MK3DC is specifically compatible with lithiums or not. The way that I understand it the charger simply connects house battery voltage to trolling batteries splitting 3 ways. I'm not going to dwell on this much longer though. I'll be moving on. Looks like the Stealth 1 DC charger will do what I need seamlessly and automatically. Begin charging the trolling batteries when the voltage is there and quit charging when not. Trolling motor on or off does not matter.

http://www.stealth1charging.com/2007/dc1.jpg

[Phisherman]

As far as I know ONLY the MK PC series chargers have the algorithm to charge lithium batteries
. That is per MK

[Team Dougherty]

I don't know that the MK3DC is specifically compatible with lithiums or not. The way that I understand it the charger simply connects house battery voltage to trolling batteries splitting 3 ways. I'm not going to dwell on this much longer though. I'll be moving on. Looks like the Stealth 1 DC charger will do what I need seamlessly and automatically. Begin charging the trolling batteries when the voltage is there and quit charging when not. Trolling motor on or off does not matter.

http://www.stealth1charging.com/2007/dc1.jpg

That's good. You should still look into using your outboard to charge the lithium starting battery. You may burn the alternator out as they are not designed to charge lithium batteries.

[Ann-Marie]

Ann-Marie,

What triggers the Yandina? Looks like it's always connected? No issues with running down the starting battery?

The Yandina Trollbridges have a built-in Combiner function that monitors input voltage to detect when the source battery is being charged. Unlike the copies made by others, Yandina VSRs draw no current until the input voltage exceeds the threshold for about 30 seconds. We have manufactured Combiners that don't need on/off switches for 27 years now.

[Diesel Pro]

In my case I want the ability to be trolling along and be able to start my main engine. I would do this for 2 potential reasons. #1 would be to allow me to continue to troll across a stretch of unproductive water by dropping the engine into gear and idling. This would save running the Ulterra wide open for extended time which is something MK warns about. The second would be if I happened to hit the end of the capacity of my batteries and wanted to simply run the main while I continue trolling using the alternator to help recover some charge.

Seems like in scenario 1 the trollbridge would require me to shut down the bow mount then restart it. That or use a "radio" to command the change. Scenario 2 is absolutely not possible with the Trollbridge as I understand. I would have to shut down the bow mount completely in order to charge the batteries.

It also seems that with the Trollbridge I would need to build my own extension leads to extend to access a split battery system with starting battery at stern and trolling batteries near bow.

[Diesel Pro]

Back to the MK3DC I still have it installed and I'll watch and see what it does next outing if I get out before I replace it, but I ran a 40 amp portable charger on my main and activated the MK3DC. Initially the charger showed it was outputing 40 amps and the staring/house battery was accepting 27 amps. The the rest went to the MK3 as well as the key on engine off accessory loads of the Merc. The MK3 just did not want to deliver the amperage staying in the 4 amp range. As the staring battery approached full it tapered off and so did the charger output while the trolling charge remained pretty consistent. I'm guessing that because the batteries are already in the 13+ range there is something in the profile limiting the amperage. As soon as I plugged my MK460PC in it went to 13-14 amps each on the trollers

[Ann-Marie]

In my case I want the ability to be trolling along and be able to start my main engine. I would do this for 2 potential reasons. #1 would be to allow me to continue to troll across a stretch of unproductive water by dropping the engine into gear and idling. This would save running the Ulterra wide open for extended time which is something MK warns about. The second would be if I happened to hit the end of the capacity of my batteries and wanted to simply run the main while I continue trolling using the alternator to help recover some charge.

Seems like in scenario 1 the trollbridge would require me to shut down the bow mount then restart it. That or use a "radio" to command the change. Scenario 2 is absolutely not possible with the Trollbridge as I understand. I would have to shut down the bow mount completely in order to charge the batteries.

It also seems that with the Trollbridge I would need to build my own extension leads to extend to access a split battery system with starting battery at stern and trolling batteries near bow.

Not a problem, Diesel, you should have called us. 24/7 email and nearly 24/7 phone. This is a common situation for our commercial fishing customers. You can install a manual override that locks out the automatic charging mode. When finished turn the override off and the batteries will be fully charged by the time you're back to the trailer. It is true that when the override is on, so that you can run both motors, the 36 volt bank will not be charged but that is what life was like in the olden days before the Yandina Trollbridge 36. :(

Yes, the Trollbridges come with six battery cables already attached, no extra charge. However nearly all installations require running a charging cable positive and negative from the starting battery to the Trollbridge, I don't know of any systems that will charge your trolling batteries from the alternator without connecting them together.

[Diesel Pro]

Yes I did call. I desire having the ability to charge and troll simultaneously so the Trollbridge is not for me.

I fully understand the need to run leads to the starting battery. Another mfr will build with the proper lead length and no need to add additional splices.

[Team Dougherty]

I'm guessing that because the batteries are already in the 13+ range there is something in the profile limiting the amperage. As soon as I plugged my MK460PC in it went to 13-14 amps each on the trollers

That is why it is recommended to make sure the charger is able to charge lithium batteries.

[Ann-Marie]

Yes I did call. I desire having the ability to charge and troll simultaneously so the Trollbridge is not for me.

I fully understand the need to run leads to the starting battery. Another mfr will build with the proper lead length and no need to add additional splices.

DUH? Name a single manufacturer who provides a built in "proper lead length" to handle trolling boats from 12 to 25 feet long. :)
Our commercial fishing customers disable charging while "on location" but re-enable on the run back to the trailer and the batteries are already fully charged for the next run.

[Diesel Pro]

DUH? Name a single manufacturer who provides a built in "proper lead length" to handle trolling boats from 12 to 25 feet long. :)
Our commercial fishing customers disable charging while "on location" but re-enable on the run back to the trailer and the batteries are already fully charged for the next run.

Stealth 1 www.chargeontherun.com makes the leads to what you request. I'm going to give it a whirl and see how it goes. No need to provide power signal, switch or press buttons, disconnect etc. Just install and go. Also contemplating a truck harness so i can charge while driving. We'll see how the onboard DC alternator charger works first.