Adding Battery and ACR

Nov 18, 2009
5
Pearson 36-2 centerboard Huron, OH
I am getting ready to add a 3rd battery for starting, a new 30A battery charger, and an
ACR between house bank (2 batteries) and the new starting battery. Also have a 125 watt solar cell. I have uploaded a schematic of how I am planning to do this, but would like any comments the experts would have. Will the solar cell, alternator, and battery charger co-exist without blowing up? This is on a 1986 Pearson 36 on Lake Erie. We do anchor overnight.
 

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Feb 26, 2004
23,047
Catalina 34 224 Maple Bay, BC, Canada
Nice job.

1. Suggest adding a Positive Bus Bar, similar to your negative bb to avoid overloading the the + post on the house battery.

2. Need to show the negative ground to the engine block.

3. Don't forget fusing.

PS - no D in bilge
 
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
Two things.

First, in that standard configuration, the ACR will tie the house and start batteries together while on shore power charging. This will force the charger to charge them as one bank, and not allow it to apply more charge to the typically more depleted house. To get around this, BSS recommend breaking the ground wire to the ACR with an AC relay sensing power applied to the AC battery charger.

Second, add an LED the supplied post on the ACR. It gives reassurance that the ACR is indeed off, and not allowing your starter battery to drain with the house while on extended anchor.
 
Feb 26, 2004
23,047
Catalina 34 224 Maple Bay, BC, Canada
I missed that. You don't need to run the shorepower charger to the start bank with the ACR installed. That's what it's there for.
 
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
I missed that. You don't need to run the shorepower charger to the start bank with the ACR installed. That's what it's there for.
Stu,

Not quite. BSS recommends that you run your shore power charger to both sets of batteries as usual, but you add the relay to stop them from being combined when on shore power charge. This happens automatically in this situation as one (actually both) batteries will show charge. This is correct behavior for alternator charging, but sub-optimal for a smart charger that can better deal with the batteries as separate banks.
 
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
Two things.

First, in that standard configuration, the ACR will tie the house and start batteries together while on shore power charging. This will force the charger to charge them as one bank, and not allow it to apply more charge to the typically more depleted house. To get around this, BSS recommend breaking the ground wire to the ACR with an AC relay sensing power applied to the AC battery charger.

Second, add an LED the supplied post on the ACR. It gives reassurance that the ACR is indeed off, and not allowing your starter battery to drain with the house while on extended anchor.
No néed to do this. The most simple method is to use th charger as a single output run direct to the house bank. Allow the ACR to charge the start. With batteries in parallel the current simply goes where it needs to.


The alt should also go to th house bank and this will limit relay cycling...
 
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
Stu,

Not quite. BSS recommends that you run your shore power charger to both sets of batteries as usual, but you add the relay to stop them from being combined when on shore power charge. This happens automatically in this situation as one (actually both) batteries will show charge. This is correct behavior for alternator charging, but sub-optimal for a smart charger that can better deal with the batteries as separate banks.

Jack,

This is 150% unecessary with single output voltage chargers and 95% of the chargers out there are single voltage regulation to all outputs. They added that blurb for their new "P" series chargers which can "float" a start bank while house is in absorption.. If you don't have a charger capable of this there is zero need to run more than one output from the charger...
 
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
Jack,

This is 150% unecessary with single output voltage chargers and 95% of the chargers out there are single voltage regulation to all outputs. They added that blurb for their new "P" series chargers which can "float" a start bank while house is in absorption.. If you don't have a charger capable of this there is zero need to run more than one output from the charger...
Agreed.

EDIT: Maine, for these 95% of chargers, do you recommend just one lead from the charger to the batteries, and let the ACR close and charge the same matter as the alternator?
 
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
Agreed.

EDIT: Maine, for these 95% of chargers, do you recommend just one lead from the charger to the batteries, and let the ACR close and charge the same matter as the alternator?
Actually for the boats we are talking about the number is probably closer to 99%. Xantrex stopped making a charger that did this a few years ago, Blue Sea has not yet launched theirs and Sterling / Promariner sell very few BCM's or "battery chemistry modules"... Charles now makes one but they are ungodly expensive and really designed for mega yachts not small sailboats..

With the typical multi-bank charger there is but one voltage program applied to all batteries despite having two or three outputs... The marketing is grossly misleading to say the least. Smart Three Bank Charger, Multi-Bank Smart Charging etc. etc....

These outputs are all on the same bus and each output usually uses a simple diode (one way electrical check-valve) to prevent back feeding from a charged battery into a discharged battery when the charger is turned off.

All battery banks get the same exact charge profile. In bulk the depply dicharged bank will dicate charger voltage holding it low until it can bring the lowest bank up to absorption voltage. The AUX bank will come up to target voltage at the same time.

Because of this there is no need to run separate outputs when you already have a combiner/ACR, Echo Charger, Duo Charger etc.. etc... They all isolate banks when not charging and charge them when charging is present. They will do this across all charge sources. Letting the Echo, Duo or ACR do the work you paid for is all you need to do.. This saves money on unnecessary duplicate wiring & fusing of the second bank and makes the installation easier..

The simple solution is to wire all charge sources, wind, solar alternator, shore chargers, hydro etc. direct to the house bank and then let the ACR/Combiner or Echo or Duo type charger handle the AUX/Start bank....

Sterling now makes a neat little battery chemistry module (BCM) but really the best use for this is when you have a GEL house bank and the main charger is set for GEL at 14.1V. Your starter may be FLA or AGM with a voltage need of 14.6V - 14.8V but your charger is now set for 14.1V to protect the GEL's. This is where the BCM comes in handy...

The BCM can boost the absorption voltage thus making the battery charger truly "smart"... The new Blue Sea "P" series chargers will not do this and can only step down the voltage to a second bank but not boost it..

The Sterling BCM however is not inexpensive and runs more than the price of a an inexpensive second charger for the start battery. A start bank may be better served with its own dedicated charger if using GEL or LiFePO4 on house, which charge at lower voltages.
 
May 16, 2007
1,509
Boatless ! 26 Ottawa, Ontario
I am not an expert but I used advice from the experts here to set my boat up as follows. All the batteries are the same chemistry. The house bank does everything including starting the diesel engine. The alternator is wired direct to the house bank. The Sterling 50A charger has the 3 outputs bussed together and wired to the battery selector switch, it is always left in the #2 house bank position. The starting battery is really just an emergency start battery, it is kept charged using an echo charger off the house bank. Nothing ever needs to be switched unless the house bank can not start the engine. This is good idea with my memory !
I would also suggest you look at including a battery monitor, it will be especially useful with your solar panel.
Bob
 
Oct 17, 2011
2,809
Ericson 29 Southport..
A question from the D.A. department. Are you guys saying that the outputs on the shore power charger are the same? That my Truecharge has a single ground, and two hot/outputs that are basically connected? I was told recently, (of which I disregarded, I believe NOTHING I hear on the docks), but this bloke stated that the charger was essentially two different chargers in one case, just sharing a ground. I seem to be reading that it is ONE charger, with two wires to make you feel better about the high-dollar purchase of a charger. ???

(Which my truecharge is not)..
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
Yes Chris the charger is one charger with two wires. You will have to confirm that the wires are (are not) disconnected from each other by a diode with an ohm meter. Some are and some are not. the ones that are not lead you to a situation of shorting between the 3-way switch effectively making the 1 and 2 setting equal to the both setting.
The fix stinks as it adds a lot of complexity to the circuit. If you have isolation between the wires then you are fine and don't need to do anything. If you don't then I'd recommend putting both wires on the house bank and using an echo charger to charge the start battery. There are other ways of wiring the circuit but they require some understand of voltage drops in circuits or determining when to turn the connecting switcherery on and off.
 
Oct 17, 2011
2,809
Ericson 29 Southport..
Youch. So theoretically, the house bank can drag down the start bank with one leg on start, and one leg on bank? That being the case, this is a stupid charger. I would be as well off with some junker from harbor freight, just buy two of them. ??
 

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Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
Youch. So theoretically, the house bank can drag down the start bank with one leg on start, and one leg on bank? That being the case, this is a stupid charger. I would be as well off with some junker from harbor freight, just buy two of them. ??
No it can't do that as each output runs through diodes...
 
Feb 8, 2009
118
Sabre 34 MK-1 Annapolis, MD
Your new understanding is spot on. One charger, two outputs.

There is a "feeling" in this thread that this is terrible. It's not, it is just not as good as you hoped. If you put in an ACR, then you can just use one output to a single battery, or jump them together to a single battery, or keep them run to both batteries -- all will have the same general effect -- with an ACR, you have basically one charger treating all the batteries as ohen bank.

HOWEVER, this does not mean that the multi-output chargers are crap or otherwise "bad." They are very useful for what they do, which is charge two batteries that are not connected. My current setup has no ACR (yet). So, my charger happily charges each battery. Granted, they are not "intelligently" charged each to their needs (same as with an ACR). But they are charged, and wihtout an ACR there is no other good way to do that. In fact, right now I have no way (other than the 1/2/B switch) to charge my reserve under way -- but since I never use it and only go out on weekends or maybe a week, I don't worry about charging it under way.

I only mention this because of the mood I was getting from the responses. The TrueCharge (and others) are perfectly suitable, and an effective way to charge two isolated batteries (or in the case of my TrueCharge 40, 3 isolated batteries). And if you send it all to one bank with an ACR, just as suitable for that.

Oh, and one other detail. They are NOT "basically connected" -- they are basically connected through isolation diodes!

Harry

A question from the D.A. department. Are you guys saying that the outputs on the shore power charger are the same? That my Truecharge has a single ground, and two hot/outputs that are basically connected? I was told recently, (of which I disregarded, I believe NOTHING I hear on the docks), but this bloke stated that the charger was essentially two different chargers in one case, just sharing a ground. I seem to be reading that it is ONE charger, with two wires to make you feel better about the high-dollar purchase of a charger. ???

(Which my truecharge is not)..
 
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
Your new understanding is spot on. One charger, two outputs.

There is a "feeling" in this thread that this is terrible. It's not, it is just not as good as you hoped. If you put in an ACR, then you can just use one output to a single battery, or jump them together to a single battery, or keep them run to both batteries -- all will have the same general effect -- with an ACR, you have basically one charger treating all the batteries as ohen bank.

HOWEVER, this does not mean that the multi-output chargers are crap or otherwise "bad." They are very useful for what they do, which is charge two batteries that are not connected. My current setup has no ACR (yet). So, my charger happily charges each battery. Granted, they are not "intelligently" charged each to their needs (same as with an ACR). But they are charged, and wihtout an ACR there is no other good way to do that. In fact, right now I have no way (other than the 1/2/B switch) to charge my reserve under way -- but since I never use it and only go out on weekends or maybe a week, I don't worry about charging it under way.

I only mention this because of the mood I was getting from the responses. The TrueCharge (and others) are perfectly suitable, and an effective way to charge two isolated batteries (or in the case of my TrueCharge 40, 3 isolated batteries). And if you send it all to one bank with an ACR, just as suitable for that.

Oh, and one other detail. They are NOT "basically connected" -- they are basically connected through isolation diodes!

Harry
Spot on. There are very few instances when a true multi-bank charger would be needed and this is only when mixing battery types of differing voltage profiles eg: GEL House & AGM or FLA start or LiFePO4 House & AGM or FLA start etc.....

The biggest problem for most is with the misunderstanding of how these chargers work and perhaps some purposely misleading marketing by charger manufacturers. That said some chargers are still a LOT smarter than others despite nearly all of them claiming to be "smart".........
 
Feb 8, 2009
118
Sabre 34 MK-1 Annapolis, MD
Some comments:

* Send the alternator to the house bank. That is the one that will need the charge, so send it there first (instead of having it go through the ACR). It will also minimize ACR cycling.

* FUSES! There should only be one wire on a battery positive (OK, 2 if you are parallelling them as you show). Come off the battery, into a fuse, and then on to the ACR, 1/2/B, etc. This reduces risk of fire from overload, and also reduces confusion when removing and replacing a battery.

* Your bilge pump right off the battery is good, but it's only the start of that kind of thing. Over time, you'll find that everyone wants to go right to your battery -- battery charger, solar charger, bilge pump, battery monitor, smart regulator, stereo backup, fridge (long wire runs are VERY bad for fridge startup), etc. I have something like 5 on my main battery and 3 on my reserve (my second bilge pump goes to the reserve). To manage all this, I've put two small 6-fuse blocks right off the battery fuses. None of these things are "on the battery" but they are VERY close.

* You can reduce lug pile-up by moving your ACR to the 1/2 terminals on the 1/2/B switch. Depending on your layout, that can make for a very neat installation with very short wires.

* I'm confused by your 1/2/B switch. Is it a standard switch (it looks like one). In that case, you don't have a "start" and "house" battery. You simply have 2 batteries, with a 1/2/B switch, and the engine and the house both come off the output. That's a great setup, and what I use (and many here recommend). However, I'd change the label. It's "main" (for me, that's #1 and a 225Ah Trojan bank), and "reserve" (for me, that's #2 and a Grp 28). I run 24/7 on "main" and "reserve" is there if I wake up to a dead battery -- switch to #2, start the engine, swtich back to #1.

Harry

I am getting ready to add a 3rd battery for starting, a new 30A battery charger, and an
ACR between house bank (2 batteries) and the new starting battery. Also have a 125 watt solar cell. I have uploaded a schematic of how I am planning to do this, but would like any comments the experts would have. Will the solar cell, alternator, and battery charger co-exist without blowing up? This is on a 1986 Pearson 36 on Lake Erie. We do anchor overnight.
 
Nov 18, 2009
5
Pearson 36-2 centerboard Huron, OH
I am getting ready to add a 3rd battery for starting, a new 30A battery charger, and an
ACR between house bank (2 batteries) and the new starting battery. Also have a 125 watt solar cell. I have uploaded a schematic of how I am planning to do this, but would like any comments the experts would have. Will the solar cell, alternator, and battery charger co-exist without blowing up? This is on a 1986 Pearson 36 on Lake Erie. We do anchor overnight.
Thanks for all of the comments. I am making some small adjustments and will post what I ended up with.