Mainship 400 going with Lithium I think?

[jefndeb]

Hello all,

I am planning to replace our 2 House 8D AGM 200ah batteries with 2 new Epoch DP12300H 300ah Lithium Dual Purpose batteries. Partially because our DC bow and stern thrusters are supplied from the house bank, (via the factory) which is really odd and I know it is killing these deep cycle batteries when blast them with a 525 amp draw multiple times on a windy day of trying to dock. Could you guys do me a favor and offer suggestions as to "where in the diagram" I would make the changes when I replace these 2 house AGM batteries to Lithium?...

I hand traced the wiring in the boat one weekend in order to develop a better understanding of the DC system and I created this Visio diagram for reference.

When I say changes, I say this because I plan to keep the one AGM 8D engine starting battery so think I have to modify the charging system somehow so the AGM battery is "isolated" so it is is charged with the correct AGM charging voltage and not the new Lithium charging voltage setting. Am I saying that right?

I know I can reconfigure the Alternators Balmar AH-5 External Regulator for Lithium and the Victron MultiPlus as well but understand that the AGM 8D shouldnt be charged with these new values..

I guess I am asking this...how does one reconfigure this system (add devices? DC to DC charger?) in order to charge both the new Lithium house bank and the AGM starting battery from the alternator with the correct charging profile...

your suggestions are appreciated...

 

[Clark]

I'm not seeing many replies to your post. It seems like there are a number of problems and questions with the schematic diagram. First, to get it out of the way, the fusing to protect wires seems to be missing is some cases. For example, the path from the house to the breaker panel has no fusing. Similarly, there's no fusing on the top bow thrusted to the first battery and on the bottom start battery to the alternator.

Second side point, I don't know if there is a normal position for the switches. Are the house batteries normally switched paralleled? Is the bow thruster switch normally open or normally closed, effectively paralleling the thruster battery with the house bank. Where does the negative from the bow thruster battery go, to the house battery negative so the shunt reads correctly when the switch is closed or to the negative bus so that the shunt read correctly when the switch is open. Granted, thruster doesn't use many AH, but it should be wired correctly depending on whether the thruster battery is part of the house or not part of the house.

Third, you have 4 charging sources here. Two battery chargers, a solar charger and finally the alternator. It is important to figure out what sources charge what batteries. Is the solar charger able to be set to charger the LiFePO4 batteries? If it is set for Li battereis then they will not be set for lead acid. ACRs from the Li to the lead batteries may not be good with the different charging profiles so maybe DC-DC 3 stage chargers, as from Victron and others, are needed. But then, they can also charge when inverter/chargers or solar chargers are running. Also, are all of the ampacities of these wires suitable for Li and do all the fuses have the sufficient AIC for a Li bank.

I seems to me that you would want to look at a redesign of the whole system based on what you want to accomplish. It is likely not going to be a simple cut and connect a wire here or there. What sources do you want to charge each battery? I recommend a GOOD marine electrician to design a system for you. Ignoring fusing, wire ampacity or the AIC rating can cause a fire, especially with Li.

A last small point, the stern thruster will cause a voltage drop when it is operated and it may cause sensitive electronics to drop out because of the transient, but it may not be damaging your house battery. I have 3 8D house batteries with a 650 amp steady state stern thruster and I have no concerns about battery damage. I would look at the battery CCA or MCA specifications and the thruster specifications to determine if they are out of align.

Clark

 

[SteveK]

This is just my opinion. Assumption single engine, one ALT.
1) I would not go dual purpose batteries, also with LFP I would not go 2 banks. Reason, with LFP house you can discharge to near zero when needed. The old system of two banks gave you a second chance if over discharged. If you have enough for needs, no worries.
2) keep the AGM start. I would add thrusters to it directly or switched and away from the house. I see you have a bow thruster bat, will that stay due to distance and line loss? Again with a switch in place I would move to the start battery as backup.
3) I would charge the new house bank from all sources directly and then charge the start battery from the house via DC2DC.
4) Not sure why you need an isolator for batteries OR how the ALT & Balmar regulator is wired to the battery. It should go direct to the house bank.

 

[DavidM]

David

 

[Avalon36]

Hello all,

I am planning to replace our 2 House 8D AGM 200ah batteries with 2 new Epoch DP12300H 300ah Lithium Dual Purpose batteries. Partially because our DC bow and stern thrusters are supplied from the house bank, (via the factory) which is really odd and I know it is killing these deep cycle batteries when blast them with a 525 amp draw multiple times on a windy day of trying to dock. Could you guys do me a favor and offer suggestions as to "where in the diagram" I would make the changes when I replace these 2 house AGM batteries to Lithium?...

I hand traced the wiring in the boat one weekend in order to develop a better understanding of the DC system and I created this Visio diagram for reference.

When I say changes, I say this because I plan to keep the one AGM 8D engine starting battery so think I have to modify the charging system somehow so the AGM battery is "isolated" so it is is charged with the correct AGM charging voltage and not the new Lithium charging voltage setting. Am I saying that right?

I know I can reconfigure the Alternators Balmar AH-5 External Regulator for Lithium and the Victron MultiPlus as well but understand that the AGM 8D shouldnt be charged with these new values..

I guess I am asking this...how does one reconfigure this system (add devices? DC to DC charger?) in order to charge both the new Lithium house bank and the AGM starting battery from the alternator with the correct charging profile...

your suggestions are appreciated...

I replaced my AGM house bank with a 400Ah LiFePO4 Battery. Start batteries and thruster battery remain AGMs. They are charged via 2 Victron DC 2 DC chargers off the Lifepo4 house bank. The thruster battery is located right next to the thruster to minimize voltage drop. From what I have read, I have serious questions about "dual purpose" Lifpo4 batteries as Lithium batteries don't generally respond well to momentary shock loads. With everything you've got going on, I would encourage you to consult a marine electrician with experience installing combined lithium/lifpo4/AGM battery solutions.

 

[Capt Ray]

I also use a DC-DC charger to charge my LA / AGM starter/bow thruster battery bank from the solar/LiFePO4 bank as needed. It is a charger that I can turn off and on. (All VictronEnergy components.)

Typically:
On shore power or underway (w/ stock CAT alternator) DC-DC charger is OFF. (Alt charges the AGM starter bank.)
On anchor, typically, the DC-DC charger is turned on.

This boat was wired with a bunch of house loads on the LA/AGM bank (cabin lights, running lights, anchor light, head, fresh water pump, etc.) It is too much work to move all that to the LiFePO4 bank so, whenever we secure at anchor, I simply turn on the DC-DC charger so the Lithium keeps the AGM bank "up" to charge for the night or extended stays on the hook Obviously, the DC-DC charger is configured for the correct charge profile for the target's battery chemistry.

The only times we need the generator is for A/C or Heat, or extended days on the hook with little to no sun.

The DC-DC charger is the ONLY connection between the two DC systems on this boat.

Two fridges, and the 3000VA inverter are on the LiFePO4 bank, and a redundant bilge pump and alarm for the aft bilge.

 

[SteveK]

@Capt Ray with your setup, why bother turning the DC2DC off?
no right/wrong just curious

 

[tiltrider1]

I do not know what to say to people who want to start engines or run thrusters off of LFP batteries.

There just isn’t any real knowledge base out there to draw from. It might work great, it might not.

I would say the best program would be to spread the load over multiple BMS’s. 4 200amp BMS’s could easily meet 600 amps.

Unfortunately, my thruster recommends 1000 CCA and my CAT engines also recommend 1000 CCA. For this reason I have a start bank and a thruster bank, neither are LFP.

 

[Avalon36]

I also use a DC-DC charger to charge my LA / AGM starter/bow thruster battery bank from the solar/LiFePO4 bank as needed. It is a charger that I can turn off and on. (All VictronEnergy components.)

Typically:
On shore power or underway (w/ stock CAT alternator) DC-DC charger is OFF. (Alt charges the AGM starter bank.)
On anchor, typically, the DC-DC charger is turned on.

This boat was wired with a bunch of house loads on the LA/AGM bank (cabin lights, running lights, anchor light, head, fresh water pump, etc.) It is too much work to move all that to the LiFePO4 bank so, whenever we secure at anchor, I simply turn on the DC-DC charger so the Lithium keeps the AGM bank "up" to charge for the night or extended stays on the hook Obviously, the DC-DC charger is configured for the correct charge profile for the target's battery chemistry.

The only times we need the generator is for A/C or Heat, or extended days on the hook with little to no sun.

The DC-DC charger is the ONLY connection between the two DC systems on this boat.

Two fridges, and the 3000VA inverter are on the LiFePO4 bank, and a redundant bilge pump and alarm for the aft bilge.

Why are you turning the DC to DC chargers on and off? What is charging the Lifpo4 when you are underway or on the hook? A stock 80 amp alternator puts out 20 amps continuous after 10 minutes which is typically enough to bring the AGMs back up

I do not know what to say to people who want to start engines or run thrusters off of LFP batteries.

There just isn’t any real knowledge base out there to draw from. It might work great, it might not.

I would say the best program would be to spread the load over multiple BMS’s. 4 200amp BMS’s could easily meet 600 amps.

Unfortunately, my thruster recommends 1000 CCA and my CAT engines also recommend 1000 CCA. For this reason I have a start bank and a thruster bank, neither are LFP.

Which is why Start and Thruster banks are separate and use AGM chemistry. They can handle the momentary high load requirements of those systems better. Lifepo4 (lithium chemistry) batteries do not handle repeated loads like that well. More BMSs will not improve the situation.

 

[Capt Ray]

Agree, from what I have been told by many LiFePO4 mfgrs: traditional lead acid batteries can tolerate the "abuse" of high amp / short duration hits like starters and bow thrusters... better than LiFePO4 can. While Dakota makes a dual purpose DL+ line of dual purpose Lithiums, most have said that that chemistry is fundamentally less tolerant. Best to stick with FLA or AGM for that. Let the Lithium house battery bank handle refrigeration, lights, head, bilge pumps, inverters, etc.

I have started, then stopped pursing the idea of putting the salon A/C on our Solar/Lithium bank for sunny days at anchor. The initial "hit" when the compressor comes on may be unhealthy. I need to research this some more, cuz some of our favorite Youtube channels have saiboats using Solar/Lithium A/C during the day when the sun is beating down on them. "Soft Start" A/C options etc.??? I simply don't know [yet].

As for the question of "Why turn off the DC-DC charger when underway?" That is a fair question. The DC-DC is smart enough to not over charge a bank that has adequate voltage levels when underway. I guess my answer is this: I like to see/monitor the solar/lithium bank behaving on its own during the day independent of the lead acid bank... and I like to see/monitor the lead acid bank behaving on its own independent of the solar/lithium. It is simply a monitoring / evaluating position to ensure everything works independently as it should. Certainly, it is a fair and good question!

 

[Dougcole]

I sincerely hope this does not create thread creep, because Jeff asks some good questions, but a couple of things.

Our Mainship 400 is twins with no thrusters, so the wiring set up is pretty different, less complex in some ways, more in others.

I know your motor is bigger but I still think an 8D starting battery is way overkill. I start both engines off of a single group 31, it works great. The 31 died this summer in the Bahamas (7 years old) and I had to replace it with what I could get, which was a group 24, 750 MCA start battery. Fired them both off just fine for the remaining six weeks we were there. I swapped it for another 31 when we got home.

There is a "DC Main" breaker on the main panel, in front of all of the DC loads other than bilge pumps, windlass and electronics. Also, most of the cabling on the 400 is quite oversized, I think it is 3/0 IIRC, it's one of the few things Mainship did right from a wiring perspective.

Our boat had the odd split 8Ds (1 each side) for both house and start loads when we bought it. the loads were divided between the banks in a very random way. I combined all of the house loads on a single bank (currently 6 6V FLA GC) and added a dedicated start battery as referenced above. The start and house banks are connected through an ACR. I like this set up a lot better.

I have 300 watts of solar on an MPT dedicated to the house bank.

My plan next year is to switch to lithium for the house bank and keep the FLA for starting. One motor with the original hitachi "dumb" alt isolated to the start and the other engine with an upgraded alt and regulator (probably Balmar) isolated to charge the house bank. My loose plan is no ACR or DC to DC charger.

 

[jefndeb]

I'm not seeing many replies to your post. It seems like there are a number of problems and questions with the schematic diagram. First, to get it out of the way, the fusing to protect wires seems to be missing is some cases. For example, the path from the house to the breaker panel has no fusing. Similarly, there's no fusing on the top bow thrusted to the first battery and on the bottom start battery to the alternator.

Second side point, I don't know if there is a normal position for the switches. Are the house batteries normally switched paralleled? Is the bow thruster switch normally open or normally closed, effectively paralleling the thruster battery with the house bank. Where does the negative from the bow thruster battery go, to the house battery negative so the shunt reads correctly when the switch is closed or to the negative bus so that the shunt read correctly when the switch is open. Granted, thruster doesn't use many AH, but it should be wired correctly depending on whether the thruster battery is part of the house or not part of the house.

Third, you have 4 charging sources here. Two battery chargers, a solar charger and finally the alternator. It is important to figure out what sources charge what batteries. Is the solar charger able to be set to charger the LiFePO4 batteries? If it is set for Li battereis then they will not be set for lead acid. ACRs from the Li to the lead batteries may not be good with the different charging profiles so maybe DC-DC 3 stage chargers, as from Victron and others, are needed. But then, they can also charge when inverter/chargers or solar chargers are running. Also, are all of the ampacities of these wires suitable for Li and do all the fuses have the sufficient AIC for a Li bank.

I agree, how does this new design loo to you?

Clark

 

[Clark]

This schematic is much clearer. Thanks.

There is a new E11 ABYC recommendation out and you may want an expert in this area to review this with respect to an overall battery fuse between the main house switch and parallel point, maybe a 500A class T.

I have a couple of observations on the schematic.

1. The ARGO FET battery combiner is not needed and can be removed. This should remove a .1V drop in your charging circuit and will be one less thing to generate heat or go bad. At least the sense leads here will compensate for this voltage drop.

2. Is the Genset start battery the same type of AGM battery chemistry as the engine start battery? When using an ACR, the two battery chemistry's should have nearly the same specifications as they will be in parallel when charging. This can create a problem if their float voltages are different. Some AGMs are 13.2V while others might be 13.5V or more.

3. The external regulator positive sense lead usually goes directly to the battery terminal to eliminate voltage drops from current flows in the main wires. In this case there are two batteries so you would have to pick one. The other option would be to tie it to the common point at the Class T if you think the voltage drop here would be small for your expected currents. I think ABYC says the fuse should be located within 7" of the batteries (or the common point at the fuse). For little 1 amp voltage sense lead fuse, I don't think they need to meet the AIC rating. Also, the shut will also create a small voltage drop if there are high currents passing through it. I would also relocate the negative sense to the same battery terminal as the positive sense or to the common point on the battery side of the shunt. This is a voltage sense, so for an ideal voltmeter/sense, there should be no current flow and thus this will not mess up the current reading of the shunt.

4. Speaking of fusing, I don't know the wire sizes in the schematic, but any time there is a transition from a thicker wire to a thinner wire at a terminal or bus bar, there should be a fuse near the transition sized to less than or equal to the ampacity of the thinner wire to protect it from overheating and starting a fire.

I hope this helps.
Clark

 

[Comodave]

I think that you should get a certified ABYC electrician to help you plan this install. Doing the design over the internet is asking for problems. Missing a step or two which could lead to a dangerous situation. Some insurance companies will deny claims if lithium battery systems are not professionally installed, check with your insurance company. Also I don’t think I would use Lithium batteries for the thrusters. For thrusters you generally need start batteries that can provide a high current for shorter periods. House banks provide lower current for long periods of. Not a good idea to mix the usage IMO.

 

[jefndeb]

Yes, I agree, I have 3 separate ABYC certified electricians reviewing this preliminary design, each one makes remarks and recommends changes as to what should be done, this drawing is a work in progress and with each suggestion, I make the changes, No parts have been ordered but getting there, BTW, the batteries I have in mind have a very high max discharge rate of 1000 amps (when 2 connected together) so that factor is key when considering thrusters.

 

[Comodave]

When you pick one electrician I would have him/her come to the boat and make specific recommendations.

 

[Capt Ray]

.

 

[Barking Sands]

Yes, I agree, I have 3 separate ABYC certified electricians reviewing this preliminary design, each one makes remarks and recommends changes as to what should be done, this drawing is a work in progress and with each suggestion, I make the changes, No parts have been ordered but getting there, BTW, the batteries I have in mind have a very high max discharge rate of 1000 amps (when 2 connected together) so that factor is key when considering thrusters.

Where are you?

 

[DDW]

If the house batteries are LFP, you have a risk of a BMS disconnect and resulting voltage spike. The Balmar module may or may not protect the system (as they themselves say). For that reason I'd consider ditching the DC-DC charging the start battery, and keep the Argofet using one of its outputs to charge the start battery. You could use a 3 output Argofet to charge the gen start battery as well, and eliminate the ACR. This would however remove solar charging on everything but the house bank.

I would in any case not use a Victron 30A DC-DC as shown. Instead use a Victron Orion XS, it is more efficient, more configurable, and more networkable. It can be set to limit to 30A or whatever you chose.

Nice diagram by the way, what did you use to draw it?

 

[jefndeb]

Yes sir, I read up some and the Orion XS seemed to be better option, I hadn't uploaded the revised dwg yet to reflect this update but I will, As far as the thrusters go I was under the impression if I went with a dual Epoch 300ah Dual Purpose battery set I would have a max Continuous Discharge Amps of 600A which would cover the thrusters I think. I used Visio originally to create drawings but no longer have access so I found a file compatible free online/downloadable drawing tool called DrawIO

 

[jefndeb]

revision 10, open to suggestions, thank you

These are the batteries I am looking at.....

12V 300Ah Pro Series - LiFePO4 Cranking & Deep Cycle Lithium Battery (Dual Purpose)

www.epochbatteries.com

 

[Delta Riverat]

Those are impressive. I could use (5) of those to do the whole boat with no worries at all.

Lithium technology just keeps getting better -

 

[Clark]

This schematic is much clearer. Thanks.

There is a new E11 ABYC recommendation out and you may want an expert in this area to review this with respect to an overall battery fuse between the main house switch and parallel point, maybe a 500A class T.

I have a couple of observations on the schematic.

1. The ARGO FET battery combiner is not needed and can be removed. This should remove a .1V drop in your charging circuit and will be one less thing to generate heat or go bad. At least the sense leads here will compensate for this voltage drop.

2. Is the Genset start battery the same type of AGM battery chemistry as the engine start battery? When using an ACR, the two battery chemistry's should have nearly the same specifications as they will be in parallel when charging. This can create a problem if their float voltages are different. Some AGMs are 13.2V while others might be 13.5V or more.

3. The external regulator positive sense lead usually goes directly to the battery terminal to eliminate voltage drops from current flows in the main wires. In this case there are two batteries so you would have to pick one. The other option would be to tie it to the common point at the Class T if you think the voltage drop here would be small for your expected currents. I think ABYC says the fuse should be located within 7" of the batteries (or the common point at the fuse). For little 1 amp voltage sense lead fuse, I don't think they need to meet the AIC rating. Also, the shut will also create a small voltage drop if there are high currents passing through it. I would also relocate the negative sense to the same battery terminal as the positive sense or to the common point on the battery side of the shunt. This is a voltage sense, so for an ideal voltmeter/sense, there should be no current flow and thus this will not mess up the current reading of the shunt.

4. Speaking of fusing, I don't know the wire sizes in the schematic, but any time there is a transition from a thicker wire to a thinner wire at a terminal or bus bar, there should be a fuse near the transition sized to less than or equal to the ampacity of the thinner wire to protect it from overheating and starting a fire.

I hope this helps.
Clark

There are two MRBF 300A fuses going to the battery switch. It looks like it is just being used as an on-off switch and it will always be set to ALL or OFF. If so, then setting it to ALL, parallels the two MRBF fuses and they likely will not blow until there is 600A on the common wire to the breaker creating roughly a 300A split between the two wires and MRBF fuses. 4/0 wire is only rated for an ampacity of 445A outside of engine spaces and 378A in engine spaces. It is likely that the wire to the breaker panel is undersized for this 600A source, since I rarely see anything larger than 4/0 wiring. Further, this 600A source is available in the ALL switch position to the other load lines tied to the 1 and 2 terminals including the bilge pumps, sump pumps, and the wires leading to the alternator. These lines are also not likely to be rated at anything close to 600A capacity.

Other posters reminded me that your house is LFP. I note there is a continuous range of storage devices available from traditional LFP battery to super capacitor all based on the same chemistry. They are almost identical except that there is a tradeoff between lifetime and how rapidly they can be charged and discharged. Super capacitors have very high charge and discharge rates but a more limited number of cycles compared to a traditional LFP battery with a more limited charge and discharge rate. There are more and more LFP batteries available that are tweaked more toward the super capacitor side to provide higher currents for starting or for thrusters than the more traditional LFP batteries. I don't have any experience with this.

If a BMS in one of your batteries takes a battery in your bank offline, how will you know? Are you thinking of batteries with blue tooth or external outputs to let you know of this event or continue to run until the second battery disconnects?

It would seem that it is critical to be very careful in setting the MPPT and external regulator charging parameters to avoid over charging that could trigger the BMS to disconnect.

Clark

 

[jefndeb]

Hey Clark, Wow, thank you very much for that pointing out my oversight, that definitely sounds critical
Can you offer a wiring correction idea or quick mark up on this dwg as to what I need to do to correct that error please? (the first paragraph error) ....

I attached the PDF file, if you send me your email I can send the actual drawio file so you would be able to open in the drawio.com web site.

Jeff 912-659-9326

 

[Don L]

I was researching battery pricing yesterday. I have had lead acid golf carts batteries, carbon foam batteries and LFP last set I got 3 years ago. I thought they were cheap 3 years ago, but the same ones are now 55% the cost of back then. I just can not see anyone getting anything else anymore. The main thing stopping some is that they have been reading forums for years and are caught up in the science project threads of installing. For reference when I installed mine all I changed were setpoints of charging sources. That was 3 years ago and the alternators and batteries are just fine.