Do you manage/switch house vs. starter batteries?

[peaman]

Did the PO also install an upgraded alternator with regulator?

Alternator is 50A. Based on your earlier post, that should be a good deal bigger?

 

[Christian Williams]

The original equipment Motorola, or similar, works fine for normal daysailing, so long as you don't discharge the batteries a lot. It charges at one rate only--and therefore just takes hours of motoring to recoup any significant depletion of the batteries.

A bigger alternator, with its "smart" regulator, can pour on the juice when the battery is low, and then gradually back off as capacity reduces.

A Balmar 100, say, is especially useful if running the engine daily to charge the batteries on a cruise. It depends on how much power you use in a day, which is easy to compute. After that it gets complicated and leaves me in the dust. Here's my approach, see links within:

E32-3 - Balmar 100 amp Alternator, Victron Monitor and Cockpit Gauges Splash Guard

.... The external regulator is mounted on the bulkhead, outside the engine compartment. The new Balmar alternator is white, to make you feel special. The issue is power. How much electricity do you need on board, and for how long, before...

ericsonyachts.org

,

 

[frosero7744]

With the end goal of developing a cruising power budget in which I have confidence, I am curious if careful sailboat owners switch between starting banks and house banks of batteries regularly?

My previous owner instructed me to leave the battery switch on "both" under all circumstances, and that has worked fine.

I have neither a functional ammeter or battery monitor at present and I am considering purchasing a monitor with a shunt that can display state-of-health and state-of-charge. The instructions I have read for several monitor models indicate that users are typically only monitoring the house bank, as the starter bank rarely reaches a fully discharged state.

So this brings me around to my subject line. Do you switch between your battery banks for starting your boat every time you go out? Other than isolating that bank for starting purposes with the main switch, do you have another setup that is preferable?

Do you just switch to the 'house' bank if you are at anchor or at sea, wanting to protect your starting bank?

Thanks in advance for sharing your practices.

This is fun. A couple thing I've noted.

1. Do not switch your batteries once the engine is running. I believe this blows the diode on the alternator. i start mine on both and stay that way unless anchored.

2. A starting battery is a different of battery than a deep cycle. You use a deep cycle for electronics etc. Neither is particularly good at the others job. Or this is what i have believed to be true from all the advertising. haha!

3. Optima has a blue top battery which says its actually both a starting battery and deep cycle making it very useful in a 32-200 with only room for (2) average sized batteries under the aft berth.

4. With 2 blue tops, you would have a true backup for both house and starting.

5. I've had this setup for the last 3 years. Haven't had a worry. Use both on the dock, and switch to just one battery at anchor to preserve a battery for starting.

 

[Christian Williams]

Don't turn the switch to off while engine running. You can switch between banks at will.

Deep cycle battery is fine for starting a diesel. No reason not to have all deep cycle batteries on a boat.

 

[goldenstate]

This is fun. A couple thing I've noted.

1. Do not switch your batteries once the engine is running. I believe this blows the diode on the alternator. i start mine on both and stay that way unless anchored.

2. A starting battery is a different of battery than a deep cycle. You use a deep cycle for electronics etc. Neither is particularly good at the others job. Or this is what i have believed to be true from all the advertising. haha!

3. Optima has a blue top battery which says its actually both a starting battery and deep cycle making it very useful in a 32-200 with only room for (2) average sized batteries under the aft berth.

4. With 2 blue tops, you would have a true backup for both house and starting.

5. I've had this setup for the last 3 years. Haven't had a worry. Use both on the dock, and switch to just one battery at anchor to preserve a battery for starting.

Thanks Fernando!

My understanding was what Christian described - don't use the big chrome "on/off" switch while the engine is operating but it okay to switch the 1/2/both dial.

I also have read in Don Casey what toddster and you mention about different battery types:

Starting batteries being specialized for short bursts of intense current (like what a gas car needs)
Deep cycle being more useful for long periods of slow draw.

In practice all of my batteries are "deep cycle" and seem to work well for starting.

As an aside - Do you have a battery bay/compartment under you V-berth? My boat came with one fully wired, so I have four battery spots. I think I have plenty of room for four 100Ah batteries, which after reading that many people go off cruising planning to rely on 1 battery alone, seems like an abundance. I should be DJ'ing a dance party with big speakers.

 

[frosero7744]

Thanks Fernando!

My understanding was what Christian described - don't use the big chrome "on/off" switch while the engine is operating but it okay to switch the 1/2/both dial.

I also have read in Don Casey what toddster and you mention about different battery types:

Starting batteries being specialized for short bursts of intense current (like what a gas car needs)
Deep cycle being more useful for long periods of slow draw.

In practice all of my batteries are "deep cycle" and seem to work well for starting.

As an aside - Do you have a battery bay/compartment under you V-berth? My boat came with one fully wired, so I have four battery spots. I think I have plenty of room for four 100Ah batteries, which after reading that many people go off cruising planning to rely on 1 battery alone, seems like an abundance. I should be DJ'ing a dance party with big speakers.

Interesting on the battery banks. I knew there was some kind of bad that would happen. I have switchophobia apparently.

These are from the survey. Some wiring was cleaned up but in general remains the same. This cubby is at the front of the aft berth, just to the right of the shaft/seal access. My battery switch was installed in the teak just on the other side of this compartment.




V Berth has these 2 cubbys and 2 more aft. i carry tools and spares there. ill have to take a better look at whats in there. Your batteries are up here?

 

[goldenstate]

V Berth has these 2 cubbys and 2 more aft. i carry tools and spares there. ill have to take a better look at whats in there. Your batteries are up here?
View attachment 40889

Yes, in the cubby nearest to the photographer I have a second set of batteries. Given how tidy your bay is, it seems likely that my double-installation was likely a modification by a worried owner or perhaps an upgrade by whoever commissioned my boat. Here's s picture of the teak base that someone built in to mine:



And then there is plastic tub that holds the actual batteries:



This bank is wired into the external regulator for the alternator (which, based on patina of age) that I assume is original to the boat. I guess this was not a standard option.

 

[bigd14]

I'm not sure how I'm supposed to feel about a 5000+ word article on a 3-position switch. I have very strong mixed feelings.

Hah, it's easy to overthink this thing, isn't it!

Fernando, that is the cleanest forward compartment I have ever seen! For your battery compartment, you might consider reorienting the straps 90 degrees and anchor them to the bottom of the battery tray to prevent any movement. More importantly, if there is not already a fuse on the positive battery cables, you should install a fuse block and appropriate size fuse on all positive wires leading from the batteries. Here is a link to an easy retrofit model for the battery cables (but it won't take care of the smaller wires which each need their own fuse if connected directly to the battery).

https://www.bluesea.com/products/5191/MRBF_Terminal_Fuse_Block_-_30_to_300A

Edit: In browsing through the Blue Sea website I see they are now selling battery chargers. I am sure these will be a high quality product like all Blue Sea's offerings. https://www.bluesea.com/products/category/9/58/Battery_Chargers/P12_Battery_Chargers

 

[Nick J]

I've been working through this as well. I currently have two group 24 batteries with a simple 1,2, both switch. I switch to both when motoring and 2 when sailing or at anchor (at least that's the plan). It works well for day sailing and if I'm by myself and can monitor the power usage. When the kiddos come aboard, which is 99% of the time, we tend to leave things on over night and end up with a dead house battery in the morning. The group 24 battery only has 40ah of usable capacity which isn't enough for our needs. We would like to leave the refrigerator on more, add a small inverter for laptop charging, and add a mobile router to take advantage of this new work from home arrangement COVID has brought us.

I have the new design mocked up on my work bench

Specifically to this conversation, I'm using a Blue Sea Systems 3 switch panel (part number 8280). this will allow independent switching of the house bank and start battery while still allowing emergency cross connect if the start battery is dead or the house bank BMS switches off. It also adds the benefit of switching off the starter while keeping the main house distribution battery connected. Most engine panels are located outside and the keys are fairly universal (at least my Yanmar panel is). It's not a huge risk, but if someone wanted to take the boat, there's nothing stopping them with my 1,2, both switch if I've left it on to keep the refrigerator on.

To keep the charging simple and take advantage of my existing equipment, I'm running all charger sources through a Renogy 50 amp DC to DC charger with build in MPPT for a future solar add. so far everything is working well on the bench. I still need to work through some balancing issues with the LifePo4 cells and prep the lockers for the new equipment. This should provide a good solution to the switching question, add a considerable amount of capacity (apx. 5x my current usable capacity), and add a small 120vac source away from the dock.

 

[Kenneth K]

Deep cycle battery is fine for starting a diesel. No reason not to have all deep cycle batteries on a boat.

Well, cost maybe. People seem to love fancy batteries now days. But if one really wants a dedicated "start" bank (battery) used predominantly just to crank up the engine, a FLA battery is cheap, readily replaceable in any location around the world, requires no special charging regimes, and seem to typically last about 7 years.

 

[Mr. Scarlett]

On my previous boat I used an ACR and an ON - COMBINE switch. Set to ON, both banks were used and the ACR directed charging to whatever bank needed it. With the engine stopped - we didn't have solar - both banks were still used until 12.35V, at which time the house bank was the only one being discharged.
We had one 464ah bank and one 232 bank - all 6V US Battery 2200XC2. For a late 60 "classic" with nothing with running and interior lights and a couple of USB chargers this was way too much. Maybe even too much for a 20 year newer boat with way more bells and whistles.

 

[Kenneth K]

Ref batteries in the V-berth and saloon seat cabinets: With sealed and AGM batteries it likely makes no difference, but FLAs are supposed to be vented while charging. The gasses produced are apparently hazardous to health, corrosive to equipment, and can be explosive. I'd think twice before putting FLAs in closed V-berth compartment.

 

[Mr. Scarlett]

I believe that passive ventilation is enough - ie: a grill or louvered cutout in the "box". at least I really hope so since when I tackle this and my panel over the winter my plan is to move the batteries from the cockpit locker to somewhere lower and forward-er.

 

[Dave G.]

My understanding was what Christian described - don't use the big chrome "on/off" switch while the engine is operating but it okay to switch the 1/2/both dial.

This is true IF your switch is operating correctly which is a "make before break" function. As they get old this doesn't happen consistently. The way to test it is with engine off turn on your salon lights and rotate the switch between the 1,2, and both positions & your salon lights should not dim or flicker when switching. If they do the switch needs to be replaced.

 

[steven]

I keep it very simple:
#1 as primary for start and house.
#2 backup.
#3. for standby - not connected but with jumper cables nearby (and approx every 90 days, re-charge #3 with a portable car battery charger)

Every third year I replace #1 with new. move #1 to #2 position. move #2 to #3 position.
So I always have three batteries that are respectively 1, 2, and 3 years old.

I use lead acid flooded car starting batteries, not deep cycle.
reasoning is if my lights or appliances go out I have backups (including paper charts).
But if I can't start the engine that's a bigger problem. So I buy cheap CCA.

I have replaced just about every end point with LED or flashlight batteries.

Your config will depend on use pattern.
I cruise inshore not far from home.
If I were coasting or passaging in open water I would probably rethink the arrangement.


--Steve

 

[Tin Kicker]

I believe that passive ventilation is enough - ie: a grill or louvered cutout in the "box". at least I really hope so since when I tackle this and my panel over the winter my plan is to move the batteries from the cockpit locker to somewhere lower and forward-er.

Venting is required for FLA and passive is OK, just remember that the tray has to be deep enough to be able to catch any spilled fluid/acid from the batteries.

The start vs deep cycle difference for FLA and AGM is basically in the thickness of the lead plates used. The discussion about which to use when is still valid IF trying to use the minimum needed for each to be cost conscious as Kenneth K wrote. However battery capabilities have improved a lot over the decades so for not a lot more $$, a combination can be bought or bigger deep cycle can be installed with enough oomph to take on both duties in the real world.

Going to a practical (not minimal) sized set of Li-ion batteries means not worrying about it.

Installing a relatively inexpensive ACR or other charge controller means both charge and one won't discharge below a pre-set level (unless switch is set to be in parallel), so again is a way to not have to worry about switch positions as well.

 

[phildogginit]

On my boat (e34-2), I have a group 31 105 amp hour house battery #2 and a similar starting battery #1.
Stock alternator on universal m25xp (30 - 50 amps).

I start from battery number #1. Once the engine is off and we are sailing, I switch to #2. I never use BOTH, and always use #2 when not motoring.

Following the very helpful instructions at marine howto:

-charging, either from the stock alternator or from solar, is directly to the house battery, and no longer goes through the wiring harness circuit (I replaced the ammeter in the cockpit with a voltmeter). A Balmar Digital duo charge charges the starter battery, but only while running the engine.

In terms of budget, a long night at anchor will drain ~15-20% of the battery #2 as estimated by voltage. We are careful. I have more than enough power with 2x100 watt solar panels to charge the battery and run a fridge during the day.

A power upgrade might be to replace the single house with 2 agm batteries, or upgrade to a high-power alternator.