Charging LiFePO4, Starter, Alternator and Shore Power

[Flatiron]

How to charge LiFePO4 and Lead Acid from both shore power connection and alternator comes up frequently. I'm finding myself in the same boat.

Initially I had decided to get a DC-DC charger (Renogy) and stick with my shore power battery charger (which does not support lithium) for the time being. The more I thought about it, the less I liked the legacy shore power charger (because of the lack of lithium support, and because it only outputs 40 amps).

This morning I came across MasterVolt's ChargeMaster Plus series. They include the ability to charge lithium and trickle charge a small starter battery (very helpful). A really interesting feature is the ability to take input from an alternator to charge each of the banks. This appears to eliminate the need for a battery isolator or separate DC-DC charger.

ChargeMaster Plus 12/100-3 | Mastervolt

The next generation of 12/100 battery chargers. ChargeMaster Plus Czone charges a maximum of 3 batteries in a fast and safe. Anywhere in the world

www.mastervolt.com

Curious if anyone has experience with this product.

 

[ohthetrees]

I’m not familiar with that particular inverter. However, many inverters (for example my victron multiplus) have the ability to “trickle charge a small starter battery”. What I have not seen yet is one that can charge with a different charge profile and voltage to the secondary battery bank. Without that capability, the feature isn’t that useful for the use case you describe, because your lead acid start battery requires different charge profile and voltages then your lithium. If this mastervolt you are talking about can provide different voltages and charge profiles to the secondary battery bank that is indeed a great feature.

Similarly, charging with current from your alternator to two different battery banks is only useful if it can provide different charge profiles to each bank. It might still be somewhat useful if you can use it as a big DC-DC charger taking input from your alternator, and outputting a lithium specific profile to your battery bank. But because of the different charge profile problem, I still see a small programmable DC-DC charger as needed to service the lead acid start bank.

 

[time2roll]

Depends also on how much of the original wiring needs to be modified. Has it been tried as is?

 

[Flatiron]

Planning on moving forward with the ChargeMaster Pro 12/75-3. DC1 and DC2 share a charging profile (in my case I'll only be using DC1, with LiFePO4 profile). DC3 can be constant voltage of 13.25 and 10A. DC3, when receiving a charge from the alternator, will charge DC1 with the LiFePO4 profile.

Would appreciate any feedback on my design. The planned changes from the existing setup are migrating the house bank from 2S3P (6 x 6V FLA golf cart batteries) to 4S2P lithium, removing the battery isolator, upgrading from a 40A shore power charger, adding a galvanic isolator, grounding the charger and adding a 250A class T fuse for the house bank. I'll be using 1/0 AWG marine wire.

Thanks!

 

[Rbob]

Flatiron,

ChargeMaster Pro looks really good, I have a Renogy DC-DC charger but have not installed. I may change my mind and thank you for the schematic and explanation.

One question I have, the start battery gets a constant 13.25v ? Is it based upon AGM starting battery profile?

 

[coachgeo]

Planning on moving forward with the ChargeMaster Pro 12/75-3. DC1 and DC2 share a charging profile (in my case I'll only be using DC1, with LiFePO4 profile). DC3 can be constant voltage of 13.25 and 10A. DC3, when receiving a charge from the alternator, will charge DC1 with the LiFePO4 profile.

Would appreciate any feedback on my design. The planned changes from the existing setup are migrating the house bank from 2S3P (6 x 6V FLA golf cart batteries) to 4S2P lithium, removing the battery isolator, upgrading from a 40A shore power charger, adding a galvanic isolator, grounding the charger and adding a 250A class T fuse for the house bank. I'll be using 1/0 AWG marine wire.

Thanks!

View attachment 71361

how is your progress? you done anything different than above..... if so why?

> also you mentioned adding shore power lithium charger...... is not that built into the Mastervolt ???
> you mention changes to your system above.... is the diagram what you are changing too??? or what you have now and your comments are how you intend to change it orrrr?

 

[coachgeo]

based on much research I ordered one of these as well ... a used ebay one at a good price. Got all excited.... then few hours later after more research.... I canceled all I ordered.

why???


.All the documentation says this works with "any alternator".... None of the docs. say you have to buy another 500 buck alt. regulator to convert your "any" alternator...discovered that in a video I found later after the ordering of the main Mastervolt system.

Also their docs on this regulator (alpha pro III) as well says..... "works on any alternator"....... then with further hours of study... NOPE... this is a lie.... will not work on my brushless alternator. soooo..... I would have to buy a whole new engine bracket kit to install a completely different high output alternator.... which would require going to a serpentine belt system and new alternator.... etc etc. all that would easily add up to another 2 grand....

nope..... nottta.... canceled it all. Very very Luckly the ebay seller accepted the cancellation.

 

[Flatiron]

.All the documentation says this works with "any alternator".... None of the docs. say you have to buy another 500 buck alt. regulator to convert your "any" alternator...discovered that in a video I found later after the ordering of the main Mastervolt system.

Can you share a link to the video you're referring to? Curious to see it myself.

how is your progress? you done anything different than above..... if so why?

> also you mentioned adding shore power lithium charger...... is not that built into the Mastervolt ???
> you mention changes to your system above.... is the diagram what you are changing too??? or what you have now and your comments are how you intend to change it orrrr?

I received the MasterVolt charger and installed it. I found their documentation extremely lacking (sounds like you did as well). Some of the functionality is hidden. To unlock the advanced capabilities requires you to also purchase the PC Gateway device, which I will not be doing.

The end result for me is that my house battery bank (12v LifePO4, 560Ah) is being charged to about 14.2 volts. My starter battery (recently replaced to 12v AGM) is hanging out about 13.x from the trickle charge. This is from shore power.

I was unsuccessful in getting my alternator to charge both the starter and house bank. Your message about this requiring a smart alternator has me curious.

I ended up using a Renogy 50 amp DC-DC charger (I had previously purchased and was hoping to return). When the alternator is running, the Renogy will kick in after the starter battery is above 13.2 volts for 20 seconds. Then the house bank starts seeing some charge.

So ... yeah. Mixed results. I'm annoyed that I had to install a 2nd device. I'm annoyed that MasterVolt requires more hardware to use features that I already payed for. I would have saved money getting the slightly older ChargeMaster without the DC in capability if I had to do it all again.

 

[coachgeo]

Can you share a link to the video you're referring to? Curious to see it myself.

Mastervolt Alpha Pro III Charge Regulator

Mastevolt Battery Accessories

www.delcity.net