| View previous topic :: View next topic |
| Author |
Message |
kennharriet
Joined: 22 Jan 2009
Posts: 539
City/Region: Grangeville
State or Province: ID
C-Dory Year: 1999
C-Dory Model: 22 Cruiser
Vessel Name: Lochsa
Photos: Lochsa
|
 Posted: Thu Apr 10, 2025 10:37 am Post subject: Lithium Conversion |
 |
|
| Seriously considering switching to lithium. I have a Honda BF90D that puts out 44 amps. I understand the alternator needs to charge direct to my AGM battery. Should the dc-dc charger be rated at 20 amps (50% of the alternator output)? Then the dc-dc charger charges the lithium house batteries. I currently have 200w of solar charging the existing AGM house batteries through a 40 amp MPPT charge controller. Also in this scenario is there any advantage to the dc-dc charger being MPPT? Thanks in advance. Ken |
|
| Back to top |
|
 |
ssobol
Joined: 27 Oct 2012
Posts: 3589
City/Region: SW Michigan
State or Province: MI
C-Dory Year: 2008
C-Dory Model: 22 Cruiser
Vessel Name: SoBELLE
Photos: SoBelle
|
| Posted: Thu Apr 10, 2025 11:13 am Post subject: |
|
|
If you have a DC-DC charger with MPPT you can charge the battery with DC, solar, or a combination (depending on the charger, some are one or the other).
I would set this up so that the engine alternator charges the AGM. The DC-DC/MPPT charges the Li batt. Some DC-DC/MPPT chargers will also charge the engine battery once the Li batt is fully charged.
Something like this:
 |
|
| Back to top |
|
|
robhwa
Joined: 04 Dec 2013
Posts: 301
City/Region: Anderson Island
State or Province: WA
C-Dory Year: 2003
C-Dory Model: 22 Cruiser
Vessel Name: Marcia C
Photos: Problemadela
|
| Posted: Thu Apr 10, 2025 11:53 am Post subject: |
|
|
I have a newer Honda 100 on a 2003 CD22. A year ago, I put in a 50A Renogy DC/DC charger with 2 100A LIFePO4 batteries and a 200A Renogy solar panel on the roof. After a Will Prowse recommendation for this combo for a van or camper, I had already put the equivalent on my 4-wheel camper with good luck. So far so good on the CD22 also. The nice thing about the combo is that the DC/DC charger integrates solar and alternator charging. After the house batteries are charged, it then keeps the starting battery charged through the solar panels, a nice touch. I put the batteries and DC/DC charger under the sink area and Wallas stove. I do worry about moisture there, but it seems to stay mostly dry there and very dry when the Wallas is on. Downside is if the combo unit fails, I guess you have nothing, but all good so far. I have heard many bad things about Renogy, particularly online, but I also set up a system in a remote yurt last year (with heated batteries) and it seems to work fine as well so far.
_________________
Rob Harrison & Marcia Ciol
Anderson Island, WA
2003 22 Cruiser "Mar-C" |
|
| Back to top |
|
|
shad
Joined: 21 Aug 2024
Posts: 34
City/Region: Seattle
State or Province: WA
C-Dory Year: 2002
C-Dory Model: 22 Cruiser
Vessel Name: C-Squatch
Photos: C-Squatch
|
| Posted: Thu Apr 10, 2025 12:57 pm Post subject: |
|
|
A diagram of my current lithium setup is below. A couple of negative bus bars are omitted from the diagram.
I was originally going with the cheaper Victron 30A DC-DC charger, but Sunbeam recommended the XS model. The XS current limits are adjustable up to 50A, and it's a relatively small unit with Bluetooth. The charger seems to be working well and displays incoming and outgoing voltage/current via the app. I limit it to 15A for my older E-Tec stator that charges up to 25A'ish. The kicker charges up to 7A and has been doing fine so far.
The battery is a budget Litime 100Ah with Bluetooth. The battery also seems to be working as intended, and the Litime app voltage/current can be used to confirm the Victron app outgoing data.
A separate Victron MPPT charger could be added to the mix for solar.
 |
|
| Back to top |
|
|
kennharriet
Joined: 22 Jan 2009
Posts: 539
City/Region: Grangeville
State or Province: ID
C-Dory Year: 1999
C-Dory Model: 22 Cruiser
Vessel Name: Lochsa
Photos: Lochsa
|
| Posted: Thu Apr 10, 2025 1:39 pm Post subject: |
|
|
| SoBelle, A question about the diagram… #12 Accessories, it seems the loads should be wired direct to the Li house battery instead of the dc-dc charger? I’m a bit confused? |
|
| Back to top |
|
|
freedomvango
Joined: 12 Dec 2024
Posts: 23
City/Region: Jacksonville
State or Province: FL
|
|
| Back to top |
|
|
thataway
Joined: 02 Nov 2003
Posts: 21497
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
|
| Posted: Thu Apr 10, 2025 4:24 pm Post subject: |
|
|
| kennharriet wrote: | | SoBelle, A question about the diagram… #12 Accessories, it seems the loads should be wired direct to the Li house battery instead of the dc-dc charger? I’m a bit confused? |
I agree with that.
_________________
Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018 to Oct. 2021
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL |
|
| Back to top |
|
|
shad
Joined: 21 Aug 2024
Posts: 34
City/Region: Seattle
State or Province: WA
C-Dory Year: 2002
C-Dory Model: 22 Cruiser
Vessel Name: C-Squatch
Photos: C-Squatch
|
| Posted: Thu Apr 10, 2025 4:31 pm Post subject: |
|
|
| kennharriet wrote: | | SoBelle, A question about the diagram… #12 Accessories, it seems the loads should be wired direct to the Li house battery instead of the dc-dc charger? I’m a bit confused? |
To take a crack at an answer for SoBelle without knowing the actual unit, either way will work assuming the charger output, ACC circuit, and battery are on a common circuit. My assumption is that there are multiple "output" terminals on the unit, or two wires are connected to the same output terminal. It also could be done with one wire running to a positive bus bar.
When the charger is running, the accessories use some of the current with the remainder charging the battery. When the charger is off, the accessories use the battery.
Overall, the "#12" diagram is not much different than connecting the "ACC" circuit directly to a battery with appropriate fuses/breakers. However, you might save some wire depending on where the charger is located relative to the accessories and battery.
Ensure you use the correct wire gauge for the round-trip (pos+neg) length:
http://circuitwizard.bluesea.com
I'd include a main fuse/breaker on the ACC circuit close to the charger/battery just in case the charger goes haywire. Definitely a fuse/breaker close to the positive battery terminals.
https://www.bluesea.com/products/5191/MRBF_Terminal_Fuse_Block_-_30_to_300A
Personally I use one fuse for the charger and a 2nd fuse for the load circuit directly wired to the battery.
https://www.bluesea.com/products/2151/Dual_MRBF_Terminal_Fuse_Block_-_30_to_300A
Disclaimer: I am not a marine electrician, and this is just how my pea brain processes it. |
|
| Back to top |
|
|
thataway
Joined: 02 Nov 2003
Posts: 21497
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
|
| Posted: Thu Apr 10, 2025 4:54 pm Post subject: Re: Lithium Conversion |
|
|
| kennharriet wrote: | | Seriously considering switching to lithium. I have a Honda BF90D that puts out 44 amps. I understand the alternator needs to charge direct to my AGM battery. Should the dc-dc charger be rated at 20 amps (50% of the alternator output)? Then the dc-dc charger charges the lithium house batteries. . Ken |
You want to limit the charge from the start battery to the DC/DC charger output to keep from over stressing the "alternator" of the Honda 90 (44 amp output). I used a Sterling DC to DC, because it was easily programable and was a 30 amp charger max. You also want to be sure there is enough current output from the engine charging system for maintenance of any other circuits (such as necessary to keep the engine running). I never allowed more than 30 amps--theoretically leaving 14 amps available for the other systems thru the DC to DC charger between the engine start battery and my 200 amp hour LiFePO4 battery bank.
I prefer to keep the solar system separate, from the engine charging system. Both can be easily monitored with bluetooth systems. |
|
| Back to top |
|
|
thataway
Joined: 02 Nov 2003
Posts: 21497
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
|
| Posted: Thu Apr 10, 2025 5:09 pm Post subject: |
|
|
I may be "technically" over fusing the circuits--but there is a relatively huge amount of current and a short could cause a fire in very short order. Anything going into or out of the LiFePO4 battery is fused within a few inches of the battery. Same for current going from DC To DC charger off the engine--with a fuse before the wire run to the Li battery.
My solar system is much larger than we use on our boats (and semi fixed), so it is also fused on the solar and MPPT controller ends--plus to the battery bank.
I personally don't see the need for the more expensive Victron DC to DC battery charger (XS "smart" controller)--If I was running it on my RV, powered by a Mercedes Diesel and 200 amp alternator, I might consider it. It is designed to be used with a "smart" alternator regulator system. The 18 or 30 amp Victron works fine for our C Dory (depending on the "alternator" output. |
|
| Back to top |
|
|
shad
Joined: 21 Aug 2024
Posts: 34
City/Region: Seattle
State or Province: WA
C-Dory Year: 2002
C-Dory Model: 22 Cruiser
Vessel Name: C-Squatch
Photos: C-Squatch
|
| Posted: Thu Apr 10, 2025 5:42 pm Post subject: |
|
|
| thataway wrote: | | I personally don't see the need for the more expensive Victron DC to DC battery charger (XS "smart" controller)--If I was running it on my RV, powered by a Mercedes Diesel and 200 amp alternator, I might consider it. It is designed to be used with a "smart" alternator regulator system. The 18 or 30 amp Victron works fine for our C Dory (depending on the "alternator" output. |
I initially tried an Amazon warehouse deals Victron 30A model that turned out to be a Frankenstein refurb lemon unit. I was going to replace it with the same new unit, but Sunbeam recommended the XS or an 18A. (The 30A was too much for my outboard, but I justified it thinking the dual lead acid batteries never burned up the stator, so why would a charge going through a charger?)
Benefits of the Victron XS relative to the 30A are:
1. Adjustable current limits.
2. Smaller size.
3. Less weight.
4. More efficient.
5. Runs cooler.
6. The app reports both input and output current/voltage. (The 30A model only reported input current/voltage and output voltage.)
The only con is the price.
Overall, if you're going to the expense/trouble and can stomach the price difference, I recommend the XS. Especially if installing in the space-constrained lazarette. |
|
| Back to top |
|
|
ssobol
Joined: 27 Oct 2012
Posts: 3589
City/Region: SW Michigan
State or Province: MI
C-Dory Year: 2008
C-Dory Model: 22 Cruiser
Vessel Name: SoBELLE
Photos: SoBelle
|
| Posted: Thu Apr 10, 2025 7:49 pm Post subject: |
|
|
| kennharriet wrote: | | SoBelle, A question about the diagram… #12 Accessories, it seems the loads should be wired direct to the Li house battery instead of the dc-dc charger? I’m a bit confused? |
Item #12 is an input to the charger (from the vehicle ACC bus) to tell it that the vehicle is on. The diagram is from the Renogy website. |
|
| Back to top |
|
|
kennharriet
Joined: 22 Jan 2009
Posts: 539
City/Region: Grangeville
State or Province: ID
C-Dory Year: 1999
C-Dory Model: 22 Cruiser
Vessel Name: Lochsa
Photos: Lochsa
|
| Posted: Thu Apr 10, 2025 9:15 pm Post subject: |
|
|
| That makes sense thank you. I read where some of the dc-dc chargers sense the alternator being on eliminating the need for a wire. |
|
| Back to top |
|
|
thataway
Joined: 02 Nov 2003
Posts: 21497
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
|
| Posted: Thu Apr 10, 2025 10:32 pm Post subject: |
|
|
| Quote: | | I was originally going with the cheaper Victron 30A DC-DC charger, but Sunbeam recommended the XS model. The XS current limits are adjustable up to 50A, and it's a relatively small unit with Bluetooth. The charger seems to be working well and displays incoming and outgoing voltage/current via the app. I limit it to 15A for my older E-Tec stator that charges up to 25A'ish. The kicker charges up to 7A and has been doing fine so far. |
The Orion 18 amp would have been a better choice over the Orion 30 for your limited DC output. I have been using an Orion 18 with my "mobile" Li battery bank in the SUV. In a boat or RV with a larger alternator, the SX would make a lot of sense.
Sunbeam--that is a name out of the past. I thought she had given up C Dory's. The last time she was active on the C Brats was about 9 years ago.
| Quote: | Benefits of the Victron XS relative to the 30A are:
1. Adjustable current limits.
2. Smaller size.
3. Less weight.
4. More efficient.
5. Runs cooler.
6. The app reports both input and output current/voltage. (The 30A model only reported input current/voltage and output voltage.)
The only con is the price.
Overall, if you're going to the expense/trouble and can stomach the price difference, I recommend the XS. Especially if installing in the space-constrained lazarette. |
Yes all of the above is true. I do feel that current into and out of the LiFePO4 bank is very important, and I use a victron system with a read out in the cabin(I phone may not always be handy).
The difference in efficiency is about 12%--in our little boats I don't believe that makes much difference. The heat is not significant in my experience--and probably is a function of the efficiency. There should be good ventilation for any products which get warm. Size--not a lot of difference--but it could be an issue.
If you take the "Best" to the next level, then why not use Battleborn or one of several batteries which are better built and marketed to the marine trade? Yes they are about 4x the cost of the "LiTime". I have the "LiTime" in my large home system, but on the boat, I used what battery seemed ot be the best at the time. The BB are more robust, and there is an electrical engineer available to talk to if there are questions. (He also facilitated my direct contact with engineers at Victron.). Our boat batteries can take a real beating if we get into heavy seas. |
|
| Back to top |
|
|
shad
Joined: 21 Aug 2024
Posts: 34
City/Region: Seattle
State or Province: WA
C-Dory Year: 2002
C-Dory Model: 22 Cruiser
Vessel Name: C-Squatch
Photos: C-Squatch
|
| Posted: Fri Apr 11, 2025 2:20 am Post subject: |
|
|
| thataway wrote: | | If you take the "Best" to the next level, then why not use Battleborn or one of several batteries which are better built and marketed to the marine trade? |
After watching teardowns of the batteries by Will Prowse on Youtube and reading some recommendations from other C-Brats, the LiTime batteries seemed like a reasonable gamble. No question that the Battle Born and Victron batteries are better built and supported. |
|
| Back to top |
|
|
|
Search
Private Messages
Profile
Log in
Register
Help
