Complete Electrical Overhaul Design - 1976 Islander 36

[Adamberti]

Firstly, I’ve spent the last several months reading through this site and learning more than I ever thought I would. So thank you to everyone who has put countless hours into sharing their knowledge. I'm really excited to get going on this project, including DIY Lithium battery (the only component I have already ordered). We have a 1976 Islander 36 with mostly original parts. We’ve had it for 5 years and have completed several upgrades (in the wrong order - lol), but it’s time to overhaul the electrical system.

A little context for the usage. The boat lives in British Columbia, Canada and so while I like to think we sail a lot, there is also a lot of motoring as we navigate the long narrow channels and inlets. Right now the trips are up to a week or so - anchorages are at most 2 nights without moving, so there’s plenty of engine time for recharging.

Medium to long term we plan some longer trips – Van Isle Circumnavigation, heading north to Haida Gwaii, and maybe even a Hawaii trip. This means short term no solar installation, but before these longer trips we would add solar into the mix. So this system is designed to accept solar in the future.

I’ve put together a preliminary diagram (attached). I will continue to refine it further down to every wire (and gauge), fuse, etc – but for now am looking for input on the decisions I’ve made, and any advice on if I’ve missed something or not considered something. I do have a couple of specific questions mixed in below:

House Battery
- My conservative energy calculations for a full day coastal sailing (with autopilot) plus overnight anchor put us at about 100 amps
- I’ve chosen 304Ah EVE cells for the house battery based on recommendations on this forum for suppliers (Jenny – Docan).
- I will use 4 cells for a 12v system to match the existing 12v on the boat.

BMS
- I’m decided on which manufacturer at this point and open to suggestions
- I like the idea of one that would communicate with other devices on the boat (So possibly Wakespeed with a majority of Victron components)

Alternator
- The boat has the original Perkins 4.108 with an original Delco alternator (40 amps I think). While the engine is in decent shape, I’m reluctant to put the labour and additional cost into a belt upgrade to take advantage of increased amps as there may be a re-power in the future
- Therefore I’ve decided on a 100 amp 6 series – The expectation being that we would run the engine generally for 2 hours a day minimum (departing anchor and arriving anchor). If we get only 50 amps each hour, we would replenish our daily usage. I can’t see a day with less than 2 hours coastal cruising.
- A Balmar 618 Regulator will keep the Alternator safe, but not looking for any of the data connections at the moment.

Overload Protection.
- The sterling device is cheap, and allows for direct charging of the battery.
- I don’t like the idea of DC to DC for charging the house battery. Seems to be counter intuitive
- I’m not fully understanding if the battery disconnects and the Sterling kicks in, what are the next steps? Can the BMS communicate with the Regulator?

Starting Battery
- I will stick with a FLA 12v starting battery. There’s no savings here – the existing start and house battery are end of life, so open to suggestions here but I don’t see a reason to go anything else here.
- Charged via DC to DC charger on a separate circuit
- I’ve currently designed the system to be separate, but am open to designs that could allow the house to be the start if necessary (short of the current plan for emergency wiring as needed).

Victron ‘Smart’ Monitoring / Operation
- The whole ‘connected’ line of Victron looks to a mess of products and poor documentation. The fact that Victron has built their online manual site to a wiki that anyone can edit is suspect.
- With the minimal documentation on the Octo, I’m not sure it’s the right product, but I used the page here to compare my needs (https://www.victronenergy.com/live/venus-os:start)
- Perhaps the Cerbo is the ‘latest’ model? It certainly looks more future proof with dual processor and double the RAM of an Octo. It appears to be less than $100 more

Bus Bars
- I have designed this with 4 post bus bars on each side of the battery. On my diagram I have indicated multiple connections on a single post by putting them close together. I believe a 100Amp bus bar should suffice for the loads. If the alternator was upgraded in the future I could go direct to the battery and bypass the bar?
- The AC& DC Panels, MultiPlus, and Octo are all on the port side of the boat, with the rest of the equipment generally on centre close to the engine and battery.
- The distance from the battery to bus bars should be relatively short (a couple feet or less)
- Is this ok, is it going to give me problems?

Thanks for taking time and providing input.

 

[Horsefly]

Too much to address here in the short time I've got, but...

I'm helping someone retrofit an Island Packet 40 with new house electrical. He's going almost all Victron. I think your impression of Victron is flat wrong. It is really, really good stuff. If there is a fault there, it is that they are a bit too customer friendly: They allow the community to contribute to their Linux-based Cerbo / Victron connect stuff, their wiki, etc. Having dealt with companies that are not consumer friendly (ahem, Schneider), I can really appreciate what Victron does. Besides that, their products are top notch, at least so far.

The system I'm helping with will have a new LiFePO4 house battery bank (560Ah), and separate engine / starter battery (100Ah AGM), and a separate bank for the bow thruster and windlass (200Ah AGM). The 100A Balmar alternator will charge the house bank via a Wakespeed 500 regulator, and the two AGM banks will be charged from the house bank via DC-to-DC chargers.

There's more to tell, but I gotta run.

 

[svsagres]

We’re embarking on pretty much the same journey as you, here in Vancouver, though we’re on an Ericson 27. Co-owner and myself are both integration geeks, and are pretty much all-in on the Victron integration, though with 3rd party components in the mix.

Battery/BMS: Cells from Docan (though we’re going 2p4s 230AHr as they fit better in our battery space. BMS we’ve chosen is the REC ActiveBMS, as it integrates with the Victron setup, and will actively manage all the charging sources.

Alternator/Regulator: Wakespeed WS500 regulator, and whatever alternator we can fit on our Yanmar engine. Not a cheap piece of kit, but infinitely configurable, and fully integrates with the REC and the VIctron setup via CANBus. As far as alternator goes, we’re going to see about modifying a 70A we have sitting around for external regulation, and/or talk with Ashnat Starters and Alternators on Broadway to see what they suggest.

Cerbo GX + Display: User interface and interconnection for everything. I could have done this with a Raspberry Pi, but by the time you add all the bits and bobs that are included with the Cerbo (interfaces, etc…) the Cerbo is cheaper.

INverter/Charger: 2000W Multiplus compact. I really wish that Victron made a smaller 120V/60Hz inverter, but it is what it is.

Orion-TR 12/12-18: DC:DC charger for our starting battery (which will stay an FLA, or maybe AGM, just big enough to start our motor).

Eventually we’ll add solar, but on a 27’ boat there isn’t much room for panels. Might do a couple of foldup panels that we can hang out when up in Desolation or Princess Louisa.

 

[Adamberti]

I think your impression of Victron is flat wrong. It is really, really good stuff. If there is a fault there, it is that they are a bit too customer friendly: They allow the community to contribute to their Linux-based Cerbo / Victron connect stuff, their wiki, etc. Having dealt with companies that are not consumer friendly (ahem, Schneider), I can really appreciate what Victron does. Besides that, their products are top notch, at least so far.

Perhaps my comment was painted with too broad of a brush Yes I have read good things about their products generally and see a lot of happy customers. That's why I'm going with a bunch of Victron kit.

I was specifically commenting as someone researching their product, and coming across a manual that looks like this: https://www.victronenergy.com/live/venus-os:octo-gx It has phrases like "Note that this document is not finished yet. Whats needs doing is.....copy bits & pieces over from the Venus GX manual as that explain how to find / connect the device".

As someone with a tech background it makes me nervous that it's a beta product without a manual!

 

[Adamberti]

Alternator/Regulator: Wakespeed WS500 regulator, and whatever alternator we can fit on our Yanmar engine. Not a cheap piece of kit, but infinitely configurable, and fully integrates with the REC and the VIctron setup via CANBus. As far as alternator goes, we’re going to see about modifying a 70A we have sitting around for external regulation, and/or talk with Ashnat Starters and Alternators on Broadway to see what they suggest.

Both you and Horsefly have chosen the Wakespeed regulator. Is the primary upgrade from a Balmar to allow communication with the BMS? I get in your case you're looking at a different Alternator.

 

[svsagres]

Both you and Horsefly have chosen the Wakespeed regulator. Is the primary upgrade from a Balmar to allow communication with the BMS? I get in your case you're looking at a different Alternator.

It’s a bunch of things. Yes, the integration with the BMS is a big thing. But also, in our case, it’s its configurability when it comes to controlling a relatively large alternator on a small engine. It also makes dealing with the whole “high voltage shutdown“ much easier, as the regulator is shut down via command, rather than just disconnecting it.

Our engine is a Yanmar 1GM10, which realistically only puts out maybe 8 or 9 HP on a good day (it was installed in 1983). What the wakespeed lets us do is keep the alternator output negligible below, say, 1000rpm so that the engine isn’t bogged down when at idle or slow speed maneuvering in the marina. It’s also got better support for halving the output via toggle switch, so when we need the power out of the engine, we can get it.

The other thing is its Zero Amps support. If/when the battery is fully charged, it will drive the alternator to keep the battery amps at 0, and just use it to power the house loads.

 

[BobR]

Firstly, I’ve spent the last several months reading through this site and learning more than I ever thought I would. So thank you to everyone who has put countless hours into sharing their knowledge. I'm really excited to get going on this project, including DIY Lithium battery (the only component I have already ordered). We have a 1976 Islander 36 with mostly original parts. We’ve had it for 5 years and have completed several upgrades (in the wrong order - lol), but it’s time to overhaul the electrical system.

A little context for the usage. The boat lives in British Columbia, Canada and so while I like to think we sail a lot, there is also a lot of motoring as we navigate the long narrow channels and inlets. Right now the trips are up to a week or so - anchorages are at most 2 nights without moving, so there’s plenty of engine time for recharging.

Medium to long term we plan some longer trips – Van Isle Circumnavigation, heading north to Haida Gwaii, and maybe even a Hawaii trip. This means short term no solar installation, but before these longer trips we would add solar into the mix. So this system is designed to accept solar in the future.

I’ve put together a preliminary diagram (attached). I will continue to refine it further down to every wire (and gauge), fuse, etc – but for now am looking for input on the decisions I’ve made, and any advice on if I’ve missed something or not considered something. I do have a couple of specific questions mixed in below:

House Battery
- My conservative energy calculations for a full day coastal sailing (with autopilot) plus overnight anchor put us at about 100 amps
- I’ve chosen 304Ah EVE cells for the house battery based on recommendations on this forum for suppliers (Jenny – Docan).
- I will use 4 cells for a 12v system to match the existing 12v on the boat.

BMS
- I’m decided on which manufacturer at this point and open to suggestions
- I like the idea of one that would communicate with other devices on the boat (So possibly Wakespeed with a majority of Victron components)

Alternator
- The boat has the original Perkins 4.108 with an original Delco alternator (40 amps I think). While the engine is in decent shape, I’m reluctant to put the labour and additional cost into a belt upgrade to take advantage of increased amps as there may be a re-power in the future
- Therefore I’ve decided on a 100 amp 6 series – The expectation being that we would run the engine generally for 2 hours a day minimum (departing anchor and arriving anchor). If we get only 50 amps each hour, we would replenish our daily usage. I can’t see a day with less than 2 hours coastal cruising.
- A Balmar 618 Regulator will keep the Alternator safe, but not looking for any of the data connections at the moment.

Overload Protection.
- The sterling device is cheap, and allows for direct charging of the battery.
- I don’t like the idea of DC to DC for charging the house battery. Seems to be counter intuitive
- I’m not fully understanding if the battery disconnects and the Sterling kicks in, what are the next steps? Can the BMS communicate with the Regulator?

Starting Battery
- I will stick with a FLA 12v starting battery. There’s no savings here – the existing start and house battery are end of life, so open to suggestions here but I don’t see a reason to go anything else here.
- Charged via DC to DC charger on a separate circuit
- I’ve currently designed the system to be separate, but am open to designs that could allow the house to be the start if necessary (short of the current plan for emergency wiring as needed).

Victron ‘Smart’ Monitoring / Operation
- The whole ‘connected’ line of Victron looks to a mess of products and poor documentation. The fact that Victron has built their online manual site to a wiki that anyone can edit is suspect.
- With the minimal documentation on the Octo, I’m not sure it’s the right product, but I used the page here to compare my needs (https://www.victronenergy.com/live/venus-os:start)
- Perhaps the Cerbo is the ‘latest’ model? It certainly looks more future proof with dual processor and double the RAM of an Octo. It appears to be less than $100 more

Bus Bars
- I have designed this with 4 post bus bars on each side of the battery. On my diagram I have indicated multiple connections on a single post by putting them close together. I believe a 100Amp bus bar should suffice for the loads. If the alternator was upgraded in the future I could go direct to the battery and bypass the bar?
- The AC& DC Panels, MultiPlus, and Octo are all on the port side of the boat, with the rest of the equipment generally on centre close to the engine and battery.
- The distance from the battery to bus bars should be relatively short (a couple feet or less)
- Is this ok, is it going to give me problems?

Thanks for taking time and providing input.

Some manufacturers recommend 100ah or 200ah for assembling marine battery banks, with 100Ah being preferred and 200Ah acceptable. Large cells don’t have the structural strength-to-weight ratio required onboard small crafts and would have a shorter life because of internal damage.



“It is common sense: as a cell becomes larger, its internal weight increases much faster than the rigidity and surface area of the casing and the casing is all what holds the plates together in a prismatic cell.”

Assembling a Lithium Iron Phosphate Marine House Bank | Nordkyn Design

This article describes the process of designing, assembling and balancing a lithium battery bank for use on a yacht.

nordkyndesign.com

 

[Adamberti]

Some manufacturers recommend 100ah or 200ah for assembling marine battery banks, with 100Ah being preferred and 200Ah acceptable. Large cells don’t have the structural strength-to-weight ratio required onboard small crafts and would have a shorter life because of internal damage.

Thanks BobR. I didn't come across that advice in my reading....Too late - batteries are shipped! That being said, it is good to understand this. I spent the morning reading Eric's articles, but the argument to me isn't iron clad.

I agree as a cell becomes larger, it's internal weight increases faster than the rigidity and surface area of the casing. BUT - we are compressing and securing our batteries in place such that we are not relying on the aluminium casing, and instead a much more rigid structure.

What I could potentially see (but I don't know the internal design of one of these cells), is that as these EVE batteries get taller, the length of the plates inside may become more fragile due to their length and how they are supported? Eric mentions that Lithium cells are generally different in just their materials used, "leaving everything else in the battery largely unaltered". https://nordkyndesign.com/lithium-battery-banks-fundamentals/

So would the same issues apply to larger lead acid batteries?

I am interested in his design of using a Dual DC Bus and charge idolaters. Thanks for the additional reading material.

 

[BobR]

I am building 2 24volt 230ah batteries for a new boat; I am switching from sail to power. I will mostly be coastal cruising the East coast / Bahamas. So the boat shouldn't be being beat, and falling off waves, too much. I used to think all that was fun.

I don't think that 300ah cells will be a problem if they are clamped and secured well.

 

[Shinebox]

I second the RecActive for use with the wakespeed and the Victron gear. In my setup, I am using the Victron Cerbo which is pretty slick. Rec BMS runs the show, and the wake speed does whatever it’s told. Can integration is very straightforward.

I would recommend a larger alternator. At 40 amps, your alternator will be at best giving you half that once it starts to heat up and the wake speed starts throttling it back. I’ve used one of these for about six years now:

https://www.qualitypowerauto.com/it...ost-Common-Straight-Across-Ear--6.6-Mount.htm (they will have a billet aluminum alternator to fit your mount)

I got mine for about half of what they’re looking for now, but it’s still great value vs a Balmar or some other “marine” alternator. I’ve run it at capacity continuously and it hasn’t missed a beat. In your case, I would order it with a single V pulley and then derate the alternator with the wake speed so your pulling maybe 70 amps or so max. Now you’ll be pushing decent amps, and that alternator will be cool because it’s not strained at her output. Also, your single v belt can handle 70 amps.

 

[Adamberti]

I second the RecActive for use with the wakespeed and the Victron gear. In my setup, I am using the Victron Cerbo which is pretty slick. Rec BMS runs the show, and the wake speed does whatever it’s told. Can integration is very straightforward.

I would recommend a larger alternator. At 40 amps, your alternator will be at best giving you half that once it starts to heat up and the wake speed starts throttling it back. I’ve used one of these for about six years now:

https://www.qualitypowerauto.com/it...ost-Common-Straight-Across-Ear--6.6-Mount.htm (they will have a billet aluminum alternator to fit your mount)

I got mine for about half of what they’re looking for now, but it’s still great value vs a Balmar or some other “marine” alternator. I’ve run it at capacity continuously and it hasn’t missed a beat. In your case, I would order it with a single V pulley and then derate the alternator with the wake speed so your pulling maybe 70 amps or so max. Now you’ll be pushing decent amps, and that alternator will be cool because it’s not strained at her output. Also, your single v belt can handle 70 amps.

The plan was always to upgrade the alt - the 40 amp is not up to par, but I didn't want to go to the effort of doing the pulley upgrade for really high output.

But, if I follow your recommendation, spend a little less on the alt - and allocate that towards a better regulator (wakespeed) then I have a much better regulator for future alt upgrades and re-powering. I thought perhaps a rebuilt alt would also be an option - just never gone down that road. I live over 1000 kilometres away from the ocean so I don't get a lot of local marine places to check out.

 

[Adamberti]

So a question to those of you with Rec BMS and Victron, how would you control Victron charging while away from the boat?

When at the Marina, I expect the only draw to be the occasional slurp from the bilge. Perhaps a little more with things like the BMS, and when we get wifi and remote connectivity.

Ideally to minimize cycles and maintain health, I would like to let the battery drop to some fairly low number (say 20% SOC) before charging all the way back up. Does that become a Rec setting or a Victron Quattro Multiplus setting (via the Cerbo?) of course when planning a trip out there I would like a quick ‘charge now’ button to bring up the batteries before arriving.

(Edited to change Quattro to Multiplus)

 

[Shinebox]

That would be on the Victron side. The BMS is going to control what happens at the end of charging, i.e. you're going to set the fully charged voltage. While Battery manufacturers commonly put this at 3.65vdc or so, there is no reason to go this far into the upper knee, and you will only reduce the cycle life of the battery. 3.4vdc or some other voltage that is in the lower portion of the upper charge knee is best. On the other end, the BMS will open a contactor for all your loads should the voltage drop below a preset threshold. Again it's best to be a little conservative here and choose a voltage that is right at the beginning of the lower knee.

I don't have a quattro, rather a Multiplus, but I imagine the setup is similar. In the multiplus settings you can specify setpoints as you like. So if you were to set the upper charging voltage in the Victron above what your REC bms setting is, the BMS would disallow anything above what you set. On the other end, if you put your charging setpoint below your BMS cutoff, the BMS would open the contactor to protect the battery and your inverter would never kick in.

 

[Adamberti]

Cool thanks Shinebox. I did mean the Multiplus and not the Quattro so the setup would be the same as yours.

Found the Rec BMS manual... looks like I have some reading to do!

 

[Shinebox]

I hear you. Without having components in hand to play with, it can seem like a lot, but it’s pretty straightforward actually. The only gripe I have with the REC is that they nickel and dime you for more or less essential components to the setup, like a Bluetooth dongle is extra, so is wifi, so is the setup software (wtf actually!)… etc. so that stinks, but it’s a great system that has the integration you’re looking for. There are other BMSs out there they have CANbus and you could probably get them to work fine (Al at Wakespeed is very responsive to questions and additional oem integrations), but I don’t think you would end paying less regardless.

 

[svsagres]

So a question to those of you with Rec BMS and Victron, how would you control Victron charging while away from the boat?

I’m just embarking on building my system (2p4s 230AHr LiFePO4 + REC BMS + Wakespeed + Victron) and my intention is to try and achieve this through the Cerbo GX that I’ve also ordered. If you install Victron’s Venus Large image on the Cerbo, that gives you Node Red, which is an automation system that allows for all sorts of programming and customization.

What I’m going to try and achieve is setting things up so that I can put the boat into “Storage/Daysailor mode” where it doesn’t work the batteries as hard, but also have the ability to remotely turn it back to “full mode” before leaving, and have it run the batteries up to 100% SOC.

I think I can achieve this by enabling/disabling charging sources based on the battery SOC, as reported by the REC. Ie if it reports 85% SOC, disable the multiplus and solar controllers until it drops down to 75% or similar, rinse repeat. However if I go into full mode, then go up to 100%.

But I’m an integration geek, and love playing with this kind of programming. However, it will have to wait until after the system itself is actually built.

 

[Adamberti]

I'm a bit like you Svsagres, day job is in IT so have an interest in the integration.

Now I'm second guessing my decisions! I've spent the last couple of days thinking about how for the price of the alternator (over $1000CAD) I could just invest that in solar now and not need the bigger alt!

After looking at a lot of photos I’m struggling to figure out where to mount them without spending sing 7K on an arch…

 

[svsagres]

I'm a bit like you Svsagres, day job is in IT so have an interest in the integration.

Now I'm second guessing my decisions! I've spent the last couple of days thinking about how for the price of the alternator (over $1000CAD) I could just invest that in solar now and not need the bigger alt!

After looking at a lot of photos I’m struggling to figure out where to mount them without spending sing 7K on an arch…

There exist cheaper alternators than Balmars that will probably fit and can be modified for external regulators. Once I get back from this business trip, I’m going to make a run by Ashnat Starters and Alternators on Broadway to see what they have on offer, and whether it makes sense to modify our existing Hitachi alternator.