Electrical questions & understanding

[john102345]

Hi all
I have very limited electrical knowledge so please bear with me, I am best trying to understand how the boat is wired.

Would I be right in assuming the following with my boat electrical system? 2011 Bavaria 36 cruiser

That the engine alternator is wired to the rectifier ( large box on the back bulkhead of the engine bay) the 3 outputs go to the 1, engine start battery lead acid 2, house bank batteries 280amp hr AGM's 3, bow thruster battery lead-acid.

That when on shore power ie hook up in the marina the installed Quick SBC NRG 45 amp hr 12volts charger charges the 1, engine start battery 2, house bank 3, bow thruster battery.

So here are the intentions/questions

I intend on installing some solar panels 2x 115-watt panels with brackets on the outside of the dodgers (have had my stainless guy make up 25 mm poles instead of the guard wires) then install a Victron solar controller MPPT to handle the panels wired directly in the batteries.
then potentially another flexible panel installed on the bimini which will be removable.

I also have fitted a basic inverter max 2000 watts which we have little use because it eats away at the 140 amp usable house bank quite quickly.
 
I have 2 x 140amp hr AGM  batteries fitted Total 280amp 140amp hr useable @ 50% @ 12v problem is I find myself running out of power after a couple of days hence the solar thoughts, I don't want to be that guy that is always running his engine on a pontoon either. hence the solar.

Would I be able to install another 2 x 140 amp hrs Total 560 amp hrs AGM batteries & still keep the existing quick SBC NRG 45amp hr charger? would it be up to the job?
I understand by doing the above I would increase my potential useable amp hrs to 280 50% of 560 @ 12volts

I did buy a Honda eu 2200 I generator thinking I could just plug the output into the shore power inlet of the boat but I get a polarity warning issue & although you have all helped me with this question in the past I did not really understand the conversation as I am not electrical savvy. something to do with floating earth & that the Honda was never designed to be used in the marine environment.
My buddy who has a Jeanneau 40 2002 his older Honda 2000 & my Honda 2200 works perfectly fine on his boat with the same shore cables, can someone possibly explain what is happening here & is the anything I can do to the Honda to get it to work with my Bavaria panel to charge / power the boat?

I am looking at the possibility of going Lithium with a Victron charger/ inverter 12v 3000-watt version which I think will charge the lead-acid engine battery, the lead-acid bow thruster & the Lithium house bank. poss 400amp hrs usable up to 80% can anyone confirm this?

dumb questions if I upgrade to lithium house bank batteries
 
Would I need to upgrade the alternator to cope with charging the Lithium or will the standard-fit Volvo d130 engine alternator work fine? charging all three?

Can I leave in place the quick SBC 501 charger to charge the engine start battery plus the bow thruster battery & buy an AC lithium charger for the lithium batteries? for when we are on shore power I am assuming that the quick SBC 501 NRG charger does not have a lead-acid AGM lithium charge option as I do not have access to the manual on the boat.

I am kind of thinking of doing the upgrades in two goes if possible

upgrade to solar then upgrade 2 more 140amp batts stay with existing 2000 watt inverter useable amps 280 then see what this season full-time use brings in shortfalls

or
upgrade to solar install 400amp hr lithium install plus lithium mains charger then stay with existing 2000 watt inverter usable amps 360

would any of the above options work for me? any pitfalls?

Thanks
John
PS If I missed anything vital info please ask






 

 

 

[symphony2]

First thing is to understand your pattern of usage and then look at best capacity and how to replace your usage. Do not worry about the engine start and bow thruster. Nether of these need any alternative method of charging, either shorepower or solar as they are almost instantly recharged after use by the alternator. If you have any concerns about a flat or dead engine start battery then install an emergency switch so that you can use the house bank to start the engine. Install a battery monitor so that you get a better understanding of what how you use your house capacity, particularly when not sailing, identifying which things are the heavy users and how you might reduce consumption. You don't say where you are located or your pattern of boat usage, as clearly liveaboard in the Med is completely different from weekend and holiday use in the UK. If the latter then as you have discovered 280ah nominal capacity is OK for coastal hopping and a night or 2 at anchor with regular shorepower top ups. Solar extends this by enabling you to replace much of your overnight usage during a typical summer day.

Your proposal to double the capacity of the bank is sound and the easiest and cheapest way of becoming more independent of shorepower. No need to change the alternator as the output is more than enough to cope with the demands of a 560Ah bank - the amount of demand is a function of the ability of the batteries to absorb the charge. Remember, if you have solar the alternator is only topping up. Likewise the 45amp mains charger is adequate - the rule of thumb is 10-12% of battery capacity - so at its upper limit, but again you are only topping up and charge acceptance once you get over 80% slows significantly.

In my view lithium is only worth considering if you can use its 3 big selling features - increased discharge cycles, lower weight/space for usable capacity and higher charge acceptance. So most attractive to long term liveaboards and long distance sailors seeking independence. just some ball park figures - FLA batteries have typical cycles of 4-500, AGMs 1000+ and lithium 2500. In UK usage FLA's typically last 5-8 years, AGMs 10-15, lithium potentially double that. Lithium is a huge investment and you need to think carefully about your charging systems. Won't go into details as there is lots written about the ins and outs of installing lithium in existing boats.

Adding 2 extra AGMs and solar is a major step up from where you are now and probably the best investment you can make.

Can't help with the problem of using the Honda other than to say it would not be my choice to have on a boat other than if I wanted to use power tools when shorepower is not available. They are noisy, inefficient and require the carriage of petrol. Similarly I can't see any benefit of having 240v through an inverter on a relatively small boat like yours - even with double capacity the amount you can use it is limited.

Hope this helps

[SYJetzt]

Agree with symphony, some additional thoughts:

Would I be able to install another 2 x 140 amp hrs Total 560 amp hrs AGM batteries &

Depends on the available space. All batteries should be close one to the other with shortest connection wiring. Adding a new battery set to an existing one (except nearly new) is not suggested, i would suggest changing all batteries of the house bank.

I am looking at the possibility of going Lithium with a Victron charger/ inverter 12v 3000-watt version which I think will charge the lead-acid engine battery, the lead-acid bow thruster & the Lithium house bank. poss 400amp hrs usable up to 80% can anyone confirm this?

Depends on the lithium cells, i have a 400AH lithium house bank and draw it down to 10% and up to 99%. I leave the 10% for safety as my BMS cuts off the system at 0%, which causes the whole boat to fall into dark. Changing to lithium is not only changing the batteries, but is a change in the whole energy system of your boat. The advertised "drop in batteries" aren't "drop in" because you have a context with your whole charging system.

Would I need to upgrade the alternator to cope with charging the Lithium or will the standard-fit Volvo d130 engine alternator work fine?

Yes, upgrade is neccesary, the original VP 115A will die for sure  ! Lithium batteries take every available amount of current and the standard alternator is capable to deliver 115Amps only for short time before overheating and sending the "magic smoke". After upgrading you get far shorter charging time as from the standard one.

buy an AC lithium charger for the lithium batteries?

I kept the quick charger and added a mains cutoff controlled by the lithium BMS. The victron inverter/ charger need a lot of space, cost a fortune and in my opinion make only sense if operated with a (weak) genset.

upgrade to solar install 400amp hr lithium install plus lithium mains charger

Keep in mind, that a lithium project is not a DIY project!! It takes a lot of planning and know how to complete such a project, and in the worst case you will end up destroying your boat by fire.
I'm an electrical engineer and learned it by the hard way too (but luckily without wrecking my boat ).

[ICENI]

Symphony 2, as usual has answered most of your questions so I am adding to this topic some things I hope will assist you.

You are sensible using Victron equipment, it is well made and performs well.   I installed a Victron BM712 battery monitor last year together with 360watts of their panels, a Mppt150/35 solar controller and other items, namely battery temperature sensors etc and this has completely transformed my boat's electrical system.   I can now, for the first time, in over fifty years cruising, keep my batteries at 50% charge (or over) which as you may know helps greatly with the life of the batteries.   The energy greedy equipment namely my fridge/freezer coolbox and the Webasto diesel heater installation now can be employed much more.   By carefully switching off when not used or needed navigation aids such as my plotter and Radar which as they are on permanently whilst sailing can drain energy quite a lot I can leave the fridge on whilst sailing as my solar keeps things topped up.   I find the bluetooth facility with my Iphone and the battery monitor very useful to keep an eye on the state of charge of the batteries anywhere on the boat   I now cruise back again in the UK having sailed in the Eastern Mediterranian over the past fifteen years and find modern Solar equipment works very well even in the cloudy UK weather.

Whenever you do electrical work, ensure that any connection made is clean and free of corrosion and also tight.   Bad electrical connections give rise to an increase in electrical resistance and can in certain circumstances be dangerous and cause arching and a possiblility of  fire.   This is particularly true in the heavy battery cable connections.

Another thing.   I expect you are aware of the reduction of performance when solar panels are in a shaded position so be careful regarding this.

Always check that the cable you use is adequate for the purpose it is intended for.   Thin cables have a greater electrical resistance than their thicker counterparts and can cause the 12v supply voltage to be reduced, sometime considerably!

If you need any advice regarding your Victron installation, feel free to contact me directly and I will be happy to assist.

Good luck and enjoy your sailing.

Chris.

[john102345]

Hi
Thank you for your considered replies I find this forum a great resource & people have always been there & got the t T-shirt which ultimately saves us sailers money Thank you.

A few answers to questions
My boat is based in Plymouth Yacht Haven Plymouth Uk
The two existing house bank batteries are 12 months old, so my plan was to just buy two more same make & size.
This year 2022 we intend on using & cruising the boat for 3 weeks on & a week off sort of a sabbatical with work. 
Normal loads ie, fridge 24hrs various phone charging electronics when sailing, & 200l freezer which we need to install possibly Dometic one

I will use a qualified marine Electrical engineer to install all of my new parts & will have a receipt/ Invoice to send on to my Insurance company for them to agree I am quite proactive & upfront with any Insurance company as I had a Land Rover Defender stolen in 2009 it was insured as a value only to argue with them for the next 8 months over the fact that I bought it privately not from a dealer & they settled the claim for 30% less because of this.

Saying that my plan is to understand what's going to be installed & run all the cables myself then let an electrical engineer connect everything up.

So from your comments, I have made the following decisions.

Install 2 more 140amp hr AGM batteries which are the same size & brand (doubling the useable to 280amp hrs)
Install two 115 rigid Solar panels on the dodgers
Install cabling for an additional 175-watt panel to be fitted on the Bimini, this will be removable in case of bad weather. Total solar install 405 watts.
Install a Victron MPPT solar controller to manage the panel's input.
Install a Victron BMV 712 battery monitor to monitor everything, as well as buy the Bluetooth version of the Victron mppt so I can monitor from my phone also.

I will take the Honda EU 2200i with me as a backup, as I have bought a Rainman watermaker which is the 240 mains 120 liters per hour version so will run that quite well.
It is a possible that I could buy a Lithium solar generator like the Bluetti AC 200p then I could always move it if I change the boat.

The question is, Would you buy & run 2 smaller Victron mppt's one for the 2x 115 panels & one for the 175watt panel on the bimini, or just 1 controller to run the total 405 watts?

Thanks again
John

 

[tiger79]

Install a Victron BMV 712 battery monitor to monitor everything, as well as buy the Bluetooth version of the Victron mppt so I can monitor from my phone also.

Before you finally decide on the Victron battery monitor, take a look at the Simarine Pico monitor.  It has far more capability, as you can install additional shunts to measure power use on different elements of the system.  It can also monitor tank levels.  It has a built-in barometer. It also has a Bluetooth function for your phone. And, as a bonus, it's a much nicer-looking display!  I fitted one and I'm very pleased with it.

[john102345]

Thank you Tiger79
Will have a look now
John

[SYJetzt]

The question is, Would you buy & run 2 smaller Victron mppt's one for the 2x 115 panels & one for the 175watt panel on the bimini, or just 1 controller to run the total 405 watts?

Would strongly suggest 2 separate controllers due to 3 reasons:
1. Interconnection of the 2 different solar module types will cause losses, so you never get 405watts out of them
2. If you plan to remove the 175W solar from the bimini, you need not to rewire the remaining system, but only disconnect it.
3. If you fit 2 controllers of the same type, you have a redundancy, and may change them one against the other in the case one has died.