Upgrade Electrical system - Hunter 33

[vandiver]

Hi all,

First post here and really happy to be part of this forum, writting from Spain. I am a very happy new owner of a Hunter 33 – 2008, have been just wondering and thinking in a “strategy” for an upgraded electrical system (assuming the current setup is not that bad though). I have the typical main battery selector OFF/1/Both/2 and have been reading a lot about it, so part of my upgrades will address this, I don’t want just to enter in major works project, as my intention is try to do these upgrades on my own, but it will all depend on the hints and difficulties I see in the planning. Here my questions in terms of priorities / steps I have thought and looking for expert advice and suggestions. Attached you can see the current setup and the “upgraded” version.

Prio 1: add an alternator protector, this is one of the first recommendations I have been reading, so that would be my first step, seems inexpensive and relatively easy to install. Some recommendations though?

Prio 2: Add a charger or combiner for bank 1 and bank 2. Here my intention as recommended in the readings is to limit the risks associated to the battery switch, so basically only using OFF and 1 (loading in parallel and isolate when not loading to protect the bank 2 and keep for backup/starter) and in parallel allow to be independent somehow from the power shore, I am not living close to the boat so I spend several weeks between visits to the boat, so my idea is to use the solar panel (currently one of 175W) to feed the two banks. Here I have seen different options and look for advice (Victron Orion Non-Isolated, Argofet, Cyrix, or also the recommended Bluesea ACR). The orion option looks nice as I could monitor it with the app (same as the recently installed battery monitor BMV712 also from Victron). The only doubt is that the device looks quite big (assume will not have so much space in the battery compartment (thinking in a second battery) but could sort it out) and maybe look for a cheaper option that can do the same, the bluetooh/APP monitoring is a nice to have but not a must have…considering all of this what would be your advice, is the best option the Victron Orion? I don’t really mind spending a bit more if that cover best my purposes, but if there are not truly advantages then I could go for something more basic…

Prio 3: Add a second battery to the Bank 1, here I am thinking into the getting the current battery in the bank 2 and install it in parallel to the Bank 1 (same model, age, and specs) and then getting a new one for the Bank 2, where its main purpose would be to have a backup for starter or service in case of need. Which battery model and capacity would you suggest/recommend for that purpose and for my boat?

Prio 4: Add a second solar panel, I have now a 175W solar panel, as the hunter 33 bimini offers good space I think I would add a second one (same model), guess that the best set up is in parallel, but have been reading many other owners install the two panels in series? Some special reason? Don’t see the advantage of it if working in 12 V or in my case, but maybe I am missing something here…That setup in parallel would lead though to change the MPPT as the model I have is limited to 260 W @ 12 V, therefore not valid for my expected 350 W (with the two panels in parallel).

Quite a long text, hope to get good advice from the experts, if you see something completely stupid with the upgrade ideas or your have suggestions to make it even better, please let me know. I am just in the learning process and getting fan of the electrics (am Mechanical Engineer, so never truly liked it before )

Thanks a lot!

[lmxr]

Welcome on cruiserforums and thank you for the clear diagrams.

There have been endless discussions about the merits and pitfalls of the two-bank setup with a 1-2-both-off switch vs. a dedicated house - starter setup. On our boat we have the latter and IMHO I suggest you switch to such a setup. The alternator and battery switch issues then solve themselves as the alternator is either connected permanently to one of the two banks (likely in combination with some Orion/ACR/Cyric to charge the other bank) or to both banks through a diode charge splitter (e.g. Victron ArgoFet).

In your "upgrade" schematic I've the impression that the two positive cables from the two banks join each other (?) and effectively put the two banks permanently in parallel. Is that your intention?

In regards to the solar setup: the better controllers on the market allow for moderate overpanelling (PV Wp > controller W). Perhaps your controller allows for this as well. Most of the time PV panels only generate around 1/4 to 3/4 of their Wp figure, so a 260 W controller for 350 Wp of panels won't reduce the amount of generated energy much. There are also endless discussions about series vs parallel. What most agree on though is that you'll need far thicker (and more expensive) cables for a parallel connection than for series. IMO I prefer series unless the panels are shaded very differently very often. If money is no question, separate controllers for each panel. To charge both banks, putting a diode splitter such as an ArgoFet after the MPPT doesn't work with all solar charge controllers as some require current from the battery to startup.

[Pete7]

As Imxr has suggested, you will be better off replacing the 1/2/off switch. BEP do a nice two switch with yellow combining switch for emergency use:

Linky

The circuit breakers you have pictured on the solar circuit are junk, sent mine straight back for a refund. The need for fuses between the solar panels and MPPT is open to debate, but certainly from MPPT to batteries. A normal DC fuse would be much better. Wiring from MPPT to batteries will need to be heavier compared to wires from panel to MPPT to reduce voltage drop. Don't undersize any of these wires to save a few Euros and then have to go back later and replace.

2 x 175A panels could generate over 20A in strong sun, seems a shame to waste this for the sake of a slightly larger MPPT.

Suggest dedicating one battery to engine start and the other for house (domestics). Then add the new second battery to the house bank. AGM is not a good choice of battery chemistry for house loads. Consider LifePO4 instead, or at least plan to go that way in the future with any purchases like chargers and MPPTs.

When engine start battery eventually fails, replace with smaller lead acid battery.

If you are using lead acid engine start batteries, can't see the point of an alternator protector. What voltage does the alternator run at now? Would be useful to know. 13.8v is rubbish but can be sorted. 14.2v probably okay once you have checked what the battery manufacturers recommendations are for the existing AGM.

Agreed nice clear diagram

Pete