"house" Battery charging

[prairieoyster]

how many keep a 2 seperate banks of batteries? 1 for house and 1 for starting an engine?

Do you have a different charging source for each set of batteries?
ie: automotive style alternator for starting battery and a "smart alternator/ Voltage control regulator" for the deep cycle ones?

I have been reading Nigel Calder's textbook, and I wonder how much of his theory is actually in practice?

 

[dhays]

I don't. I have one house bank.

If I was to keep my current boat, I was going to add a separate start battery. Very simple system but I have a very simple boat. Single, small HP engine. Crappy alternator on the engine, no solar or wind generation, no genset, and just shore power charging.

I was going to add a small 12v start battery that was charged by an Echo charger from the house bank. All charging sources go directly to the House bank, once it is up to a given voltage, the echo charger starts to charge the start battery. In this way, I couldn't strand myself with a dead starter battery and there is no management involved in keeping the start battery charged up.

Again, very simple system and not appropriate for many of the boats here on TF.

 

[Britannia]

On my current boat I have just one house bank. There is a separate starter battery that is charged via an echo charger - so it remains isolated. I do have a selector switch that allows me to start the main from the house bank if the starter battery fails.

Each of my two generators has its own start battery that is isolated and charged only by the generator. Either generator can charge my house bank and starter battery via my a/c charger.

My old sailboat came with two equal sized batteries that were used for house and starter purposes. This is a common arrangement that I didn't like. In practice, I had to reserve half my house bank capacity to start the engine. Otherwise I could risk draining the batteries down too far and be unable to start the engine. I combined the two into a single house bank and added a smaller starter battery. The starter battery was isolated from the house bank via a voltage sensing battery combiner that only combined them when it detected that one or other bank was being charged. It worked well and effectively doubled my house bank capacity.

Richard

 

[Aquabelle]

I have a House bank that is charged by BOTH alternators, combined via a Balmar CenterFielder. The batteries are 6v Trojans in series and parallel. I also have a Cranking bank that starts twin engines, powers the bowthruster and the davit. And a separate single battery for genset start. The Cranking bank and the genset start are all the same battery type: Optima 34M spiral-wound AGMs, made specifically for cranking/starting. The Cranking bank and the genset start are charged with echo-chargers off the House bank (actually, Balmar duo-chargers, which are programmable to cope with different House-to-Other battery technologies and which have temperature sensors to further adjust charging profiles. I can inter-connect any combination of the House/Cranking/genset start banks/batteries if necessary...but that hasn't been necessary. Batteries last 9-11 years in this set-up and charging is pretty well set-&-forget.

 

[FF]

Most boats will use the start batt // house batt setup.

What is no longer common is dividing a large house set in half with a rotary switch and using each half alternatly.

This is only done today IF two large alts are available during the charge period to shorten the charge time.

They are then recombined for house use after the charge period is over.

 

[Larry M]

We're a single engine vessel with one house bank, one start/engine bank, each with it's own voltage regulator and alternator with no interconnecting switches. The generator also has it's own alternator with regulator. Three independent systems.

 

[Nomad Willy]

We have two house batts and one start batt. We always keep the start batt for it's intended purpose.


We have a Zantrex that takes care of the charging allocations. And a 135amp alternator providing power when away from shore power. One start batt and two house. And a main selector switch that allows us to switch batt or batts are selected.

Interesting FF about the equality divided banks whereas one half of the bank is always availible for starting purposes. Never heard that.

 

[Baker]

I have one bank(4 105 a/h GRP31) all combined as house and start. They can be isolated if I feel the need. I usually do not. I also have a separate start battery for the generator. So if I were to run the main bank down, I can still start the generator and charge the main bank. A VERY simple system that has served me well on other boats as well as this one.
I am installing an inverter next week as well as a monitor. I was under the impression that this was gonna be sorta cheap....after getting all the bits and pieces...NOT cheap.

 

[prairieoyster]

Larry M,
What brand of alternators and Voltage regs. do you use? are both alternators same.

 

[prairieoyster]

Barker,
Your experience is exactly what I'm trying to avoid. I hope to build a simple boat. This whole charging system knowledge has me in a flap, cause I know too much. I suspect the solution is to keep the electrical demands to a minimum and keep the charging battery charged with an alternator on the main engine.
Generators seem to add double redundancy and they create a good back-up solution.

 

[DavidM]

There are really two parts to your question: 1) the need for a separate house bank and 2) how to charge and isolate separate banks.


1. Starting batteries and house batteries are built differently. A starting battery that is routinely discharged to 50% for house use isn't going to last very long. And it is somewhat difficult to know what is truly a deep cycle designed house battery. A published amp hour rating is one good clue. Most so called dual purpose batteries don't do that and almost all dual purpose batteries are not true deep cycle.


2. If you are going to hang out on the hook for a day or so, you run the risk of running down both your house and starting batteries if they are connected together. Then your engine won't start.


The simple way to solve this is to put the starting battery on the #1 circuit and the house battery on the #2 circuit and turn the 1,2,all switch to #2 while on the hook and then back to #1 when you start the engine and then to all when it is running and charging from the alternator or back at the dock on shore power.


But that drill is easy to forget and an automatic way is to isolate the starting bank with a combiner, ACR, Echo Charger, etc. That probably requires some rewiring to accomplish.


David

 

[Larry M]

Larry M,
What brand of alternators and Voltage regs. do you use? are both alternators same.

The 3 stage voltage regulators are from Ample Power, Seattle and we carry an interchangeable spare.

The alternators are a mix but they are 110 amp, small frame and single belt. The mounting's are the same for both plus the spare that we carry.

 

[LarryM]

I have separate start, house (2x6vGC), thruster and generator batteries. The 55A alternator charges the start batt, a 40A Xantrex charger maintains the house bank and an ACR combines/isolates the two. Finally Echo Chargers are connected to the thruster and generator batteries from the house bank.

It sounds a little complicated for such a small boat, but is completely automatic and works well for the way I use the boat.

I don't have the ability to cross-connect between banks other than combining the start and house (via an ACR remote), so I carry a high-quality set of jumper cables long enough to reach any pair of batteries. I have never used them, but several boaters on my dock have.

 

[Bacchus]

Many Mainships have 2 (or more) 8D batt'y banks but they are not dedicated to start / house... instead they switched the start function & house loads but the dedicated full time "house" loads (bilge pumps, hi water alarm, CO detectors, etc) were split prior to the switch.

I did some rewiring to replace the factory diode isolators w/ a Sterling CVSR.

Here's a link w/ a description of the mods including before / after wiring schematics.

Bacchus Alt & AC Charging Mods

I would definitely separate house / start systems if starting over but I wasn't ready to tackle a major rewire at the time. Simple charging via echo charger / combiner a plus especially if single engine / alt.

 

[dhays]

There are really two parts to your question: 1) the need for a separate house bank and 2) how to charge and isolate separate banks.


1. Starting batteries and house batteries are built differently. A starting battery that is routinely discharged to 50% for house use isn't going to last very long. And it is somewhat difficult to know what is truly a deep cycle designed house battery. A published amp hour rating is one good clue. Most so called dual purpose batteries don't do that and almost all dual purpose batteries are not true deep cycle.


2. If you are going to hang out on the hook for a day or so, you run the risk of running down both your house and starting batteries if they are connected together. Then your engine won't start.


The simple way to solve this is to put the starting battery on the #1 circuit and the house battery on the #2 circuit and turn the 1,2,all switch to #2 while on the hook and then back to #1 when you start the engine and then to all when it is running and charging from the alternator or back at the dock on shore power.


But that drill is easy to forget and an automatic way is to isolate the starting bank with a combiner, ACR, Echo Charger, etc. That probably requires some rewiring to accomplish.

In the diagram that I posted above it is a little unclear, but my boat came with a split house bank controlled by a 1/2/Both/Off type switch. Terrible setup that was/is all too common on sailboats. My boat also had a simple On/Off engine switch. I rewired it as shown which was actually very simple to do. I am only familiar with the Echo Charger, but it is stupidly easy to install and wire. Just a hot lead from the house battery to the start battery and a ground.

What is not obvious from the diagram is that normally the 1/2/B/O switch is kept in the #1 position and the On/Off is kept on. This isolates the two batteries with the Echo charger charging the Start Battery.

If the Start battery should fail for some reason, turn the On/Off switch to Off, turn the 1/2/B/O switch to Both, and the House Bank is connected to the starter and the Start Battery is completely isolated. If the House Bank fails, then turn the On/Off switch to On, the 1/2/B/O switch to #2 and the Start battery is connected to the starter, isolated from the House bank, and will give you some house current for critical systems (nav lights, VHF radio).

Outside of a battery failure however, the switches never need to be changed. So simple, even I can do it.

Having said that, I had an offer accepted on a boat with a "real" motor, genset, a bunch of different batteries for bow and stern thrusters, genset start, engine start, and house bank. It will take me a long time to figure out how all that works together.

 

[RCook]

There are really two parts to your question: 1) the need for a separate house bank and 2) how to charge and isolate separate banks.


1. Starting batteries and house batteries are built differently. A starting battery that is routinely discharged to 50% for house use isn't going to last very long. And it is somewhat difficult to know what is truly a deep cycle designed house battery. A published amp hour rating is one good clue. Most so called dual purpose batteries don't do that and almost all dual purpose batteries are not true deep cycle.


2. If you are going to hang out on the hook for a day or so, you run the risk of running down both your house and starting batteries if they are connected together. Then your engine won't start.


The simple way to solve this is to put the starting battery on the #1 circuit and the house battery on the #2 circuit and turn the 1,2,all switch to #2 while on the hook and then back to #1 when you start the engine and then to all when it is running and charging from the alternator or back at the dock on shore power.


But that drill is easy to forget and an automatic way is to isolate the starting bank with a combiner, ACR, Echo Charger, etc. That probably requires some rewiring to accomplish.


David

Our setup is very much as djmarchand describes. We switch to the start bank to start, stay that way for 10-20 minutes while the windlass raises the anchor and we get the start bank recharged, then switch to the house bank. We leave the switch there until the next time we need to start. Easier to remember, for me, than switching to BOTH while cruising, and then back to house after anchoring. An ACR/VSR could do this more automatically, but I've never felt the need for one.

Since all batts are AGM, the same alternator and regulator doing the charging for both works well. 17 years operating this way without a problem.

 

[danderer]

I've got a single deep-cycle bank charged by the alternator and a 110VAC charger. That bank supplies all house loads and is plenty-powerful enough to spin the engine. No separate 'starting' battery.

I manage things so as not to let the batteries go below around 40%. I suspect that even at 10% they'd spin the engine. But what if I really screw up?

The generator does have its own battery. So fire the gen, charge the main bank. But what if the generator won't start?

I have a switch to tie the generator battery to the main bank to start the engine in this case. That switch is never on except in this type of exceptional situation. But what if pirates steal the generator battery?

I could, but don't, just carry a set of jumper cables to start off the thruster battery. There is a limit to reasonable redundancy.

To me the important thing is to have options. Having a separate 'starting' battery might get you that (depending on how it is done) but there are other options to get options.

 

[DavidM]

danderer:


Here is an example of how you can make redundancy happen that you may appreciate. Years ago we took our brand new Mainship 34T out for an overnight anchoring. I hadn't as yet gone through the electrical system to figure everything out and the next morning the engine wouldn't start as I had run both the start and house batteries down. And no generator.


But I did have my tools on board and the bow thruster battery was isolated from the start and house batteries. So I disconnected the cable to the bow thruster battery and was just able to just reach over and touch it to the big lug on the starter. The engine started and that saved us a BoatUS call.


So, don't forget the bow thruster battery as a source of redundancy.


David

 

[TDunn]

Both my boats have two battery banks (start and house). On the power boat the engine alternator (115 Amp) is connected directly to the start battery. The start battery is then connected to the house batteries via a battery combiner relay so the alternator charges both battery banks. In addition my solar panels are connected to a dual output controller that splits the charge 90:10 to the house and start batteries.

On my sailboat the start and house batteries are also connected by a combiner relay so the engine alternator charges both battery banks. The solar panels only charge the house bank.

On both boats I can interconnect th two battery banks for emergency starting.

 

[FlyWright]

This was the configuration of my twin engine boat a few years ago shortly after upsizing my house bank to 660 AH.

Then I found the 30A charger insufficient so I replaced it with a single bank 55A charger connected directly to the house and via Yandina combiner to the start. A friend made me an offer I couldn't refuse on a slightly used Balmar 120A alternator so it now resides in place of the 75A stbd alternator. It is externally regulated with a Balmar MC-614-H regulator.

Both House and Start banks are charged directly from their respective alternator without switches. The 1-A-2-O switch on the house and ON/OFF switch on the start bank controls loads only. When the house bank is receiving a charge and the Yandina Combiner is selected on with a small toggle switch at the lower helm, the start gets a shared charge from the 55A shore charger. When underway, this combiner switch is normally left in the OFF position since each bank gets its own alternator charge.

A Xantrex battery monitor provides a great look at the amps, voltages and battery SOC.

With the loads completely separated, I always have start power. If the start batt was to die, selecting ALL on the 1-A-2-O switch will tie the banks together for a start from the house bank. If all else fails, I can start my Honda gen to charge any or all banks.

I like redundancy.

 

[Nomad Willy]

Richard,
You wrote in post #16 "We switch to the start bank to start, stay that way for 10-20 minutes while the windlass raises the anchor and we get the start bank recharged, then switch to the house bank."

Why do you do that?
Do you want a tad more speed on the anchor winch?
Are you afraid of running the start batt down?

I always switch the start selector to house right after starting. I have a Xantrex as pictured in Al's post above. May be different but when we bought the Xantrex 10 years ago they said it would take care of that and the start batt remains charged .... always. And even when it's cold in Alaska I never employed both banks to start the engine.

 

[psneeld]

Asking what DC system setup you have is like asking "how do I drive from NJ to California?"


Are you riding a motorcycle? What Time of year? Transporting a 45 foot cruise on a flatbed? Riding with 5 young kids?....holy cow...what a question.

Depending on loads, engines, alternative charging sources, choice of separating systems or not, etc, etc.... will determine what people have set up.

There are at least a couple ways to set up every single boat out there.

Just depending on how you boat, where you boat, what you are willing to spend...etc...etc...may determine how it is done.

Like expensive home remodeling or landscaping...designing a DC electrical system for a decent sized cruiser might require the "knowledgeable" person to be connected to your hip till it is done. It will be neither right or wrong...just hopefully suited for your needs.

Many have very limited knowledge of what it really takes to cruise, recharge and wire a decent setup...so beware of too many suggestions for YOUR desired application.

 

[FlyWright]

The OP questions were much more specific than your post suggests. Here's another look at the OP's questions:

"how many keep a 2 seperate banks of batteries? 1 for house and 1 for starting an engine?

Do you have a different charging source for each set of batteries?
ie: automotive style alternator for starting battery and a "smart alternator/ Voltage control regulator" for the deep cycle ones?"

 

[Xlantic]

The OP questions were much more specific than your post suggests. Here's another look at the OP's questions:

"how many keep a 2 seperate banks of batteries? 1 for house and 1 for starting an engine?

Do you have a different charging source for each set of batteries?
ie: automotive style alternator for starting battery and a "smart alternator/ Voltage control regulator" for the deep cycle ones?"

My boat has three banks: house, starboard engine, and port engine/generator. The house bank is made up of deep cycle batteries and the engine banks of cranking batteries.

Each engine charges its own bank and I a switch that can combine the house bank with either engine bank for charging the house bank while under way (and when using the windlass).

The charger has three charging outputs, one for each bank, for charging from the genny or shore power.

I would like to split the generator battery from the port engine starting bank but I need a way to keep it charged with the charger.

 

[djones44]

Barker,
Your experience is exactly what I'm trying to avoid. I hope to build a simple boat. This whole charging system knowledge has me in a flap, cause I know too much..

You could do what I do. I have a vintage vessel with an inscrutable past. My strategy: Get a Xantrex, follow the instructions, and then let the ghost in the machine sort it out. Thereafter, I just bring the batteries water, light a candle, and take their temperature with a voltmeter.

If there are no sudden flashes or black dips in the intervals, I anoint myself a genius.

 

[dsherburn]

I keep two separate banks. The start battery is always isolated. The exception is the ACR. If the ACR senses a charge on either battery (shore powered charger or alternator) it will combine the batteries. Once there is no charge present, it will isolate them. If I run the house down to "0", the start battery should still crank the single diesel.

I used to have the 1-2-both switch, but replaced it. Too easy to drain both batteries if my attention slips....

 

[markpierce]

The OP questions were much more specific than your post suggests. Here's another look at the OP's questions:

"how many keep a 2 seperate banks of batteries? 1 for house and 1 for starting an engine?

Do you have a different charging source for each set of batteries?
ie: automotive style alternator for starting battery and a "smart alternator/ Voltage control regulator" for the deep cycle ones?"

I have a starting battery and house battery. They are charged by the engine's alternator, and when the inverter is working, from the AC dock current. No genset here.

 

[FlyWright]

I would like to split the generator battery from the port engine starting bank but I need a way to keep it charged with the charger.

Have you considered a combiner like a Blue Sea ACR or Yandina combiner? Since your stbd alternator charges your start batt, when you add another start batt to the port side, the charge can be shared with the new port start batt through a combiner/automatic charging relay. They tie together when the charge is present and split when the charge stops.

I currently (no pun intended) have a single start 8D battery for both engines. When I replace it with a couple Group 31s, I'll charge both with the port alt through a combiner. They work great without the need to throw switches.

 

[angus99]

"house" Battery charging

I'm changing from two medium-sized combination start/house banks to a large (1,248-AH) house bank and single 8D AGM start battery for both engines and the genset.

I'm replacing the original 70-amp alternators, one of which was dedicated to each bank, with 100-amp externally regulated alts. The smart regulators are Balmar MC614Hs and, with a Centerfielder, are designed to take the output of two alts and optimally charge the eight 6-volt AGM J305s in the house bank. A Balmar DuoCharge will ensure that the start bank is also charged and I'll be able to start the engines or genset from the house bank if necessary. Also planning to add solar to this setup and the upgrade will include new cabling, conduit, breakers, fusing, etc. Finally, I've installed a Magnum MS2812 inverter charger and will retain the existing Xantrex 40 as a backup. The genset will be able to power either charger.

This setup is comparatively simple and based on systems successfully used by other Defever owners. I'm doing most of the work myself under the guidance of a marine electrical systems designer (per ABYC standards) and will have a marine electrician idiot-check my work. Doing it myself is fun, saves a ton of money and is the best way I know to get a thorough understanding of my electrical system.

I'll post some photos eventually.

 

[FlyWright]

I'm changing from two medium-sized combination start/house banks to a large (1,248-AH) house bank and single 8D AGM start battery for both engines and the genset.

I'm replacing the original 70-amp alternators, one of which was dedicated to each bank, with 100-amp externally regulated alts. The smart regulators are Balmar MC614Hs and, with a Centerfielder, are designed to take the output of two alts and optimally charge the eight 6-volt AGM J305s in the house bank. A Balmar DuoCharge will ensure that the start bank is also charged and I'll be able to start the engines or genset from the house bank if necessary. Also planning to add solar to this setup and the upgrade will include new cabling, conduit, breakers, fusing, etc. Finally, I've installed a Magnum MS2812 inverter charger and will retain the existing Xantrex 40 as a backup. The genset will be able to power either charger.

This setup is comparatively simple and based on systems successfully used by other Defever owners. I'm doing most of the work myself under the guidance of a marine electrical systems designer (per ABYC standards) and will have a marine electrician idiot-check my work. Doing it myself is fun, saves a ton of money and is the best way I know to get a thorough understanding of my electrical system.

I'll post some photos eventually.

Angus, you're my hero! Sounds like the perfect system for your circumstances. If I didn't have to fish, I'd have more money to throw at my electrical system. But, since I do...

Goodonya!!!