Battery Banks and Charging

[mitiempo]

Originally Posted by btrayfors

I've found that the Blue Sea Systems #6006 ON-OFF switches are great. Low cost, very robust, small, and can be flush or face mounted.

I do favor the use of simple ON-OFF switches, though, since they're easier to understand and help to avoid user errors. One for the engine starting circuit. One for the house circuit. Depending on the battery locations, a simple jumper cable might be kept handy for emergencies, avoiding the need for a third switch or a 1-2-Both-Off switch.

I have implemented this system on a number of client boats, and they tend to like it very much.

Bill

That is what I have on my boat - 2 on/off switches without the third for combining. Most of my customers already have the 1/2/both switches so most often I work with that as it's already there.

I agree - I have never had a problem with a Blue Seas switch - or any of their other products for that matter.

[goboatingnow]

Originally Posted by mitiempo

Usually it's a 1/2/both/off switch and it is used on most boats from the factory. In a cruising sailboat there is most often a house bank of multiple batteries and a single start battery. If the start battery is down too much to start the engine switching to the house bank works. I can't think of a good reason to combine a good with a drained bank - unless the switching doesn't allow it.

Jumping a car is a different issue, and usually the donor car is running and therefore charging so no problem.

Interesting reading about switch wiring here:1/BOTH/2/OFF Switches Thoughts & Musings - SailboatOwners.com

In almost all European production boats the on-off switch used. The 1-2 both switch causes confusion and can be left switched to the wrong circuit.

Secondly the1-2 both was designed for simple two battery situations for proper operation you really need two 1-2both switches one on each bank. Nope too confusing.

Next time try jumping. The car batteries without the engine running. The world doesn't come to and end ( it would with lifepo4 batteries of course)

Dave

[mitiempo]

Originally Posted by goboatingnow

In almost all European production boats the on-off switch used. The 1-2 both switch causes confusion and can be left switched to the wrong circuit.

Secondly the1-2 both was designed for simple two battery situations for proper operation you really need two 1-2both switches one on each bank. Nope too confusing.

Next time try jumping. The car batteries without the engine running. The world doesn't come to and end ( it would with lifepo4 batteries of course)

Dave

If 1-2-both switches can cause confusion why would you want 2 of them?

I can't see any advantage to 2 1-2-both switches over 1 assuming 2 banks.

[msponer]

Originally Posted by goboatingnow

If you go down the echo charge route, which in my view is the best. Then you can mix starter and domestic battery types as you wish. You could have AGMs on the domestic and a sealed VRLA on the starter. It's always best to have the correct battery type per application.

The Echo Charger is just a relay. It does not adjust the voltage, so you can't use it to mix batteries of different types.

The "sealed VRLA" thing is also off, but ... I don't want to get into a recursive conversational loop on disconnected trivia. a recursive conversational loop on disconnected trivia. a recursive conversational loop on disconnected trivia. a recursive conversational loop on disconnected trivia. a recursive conversational loop on disconnected trivia.

Haha

[Viking Sailor]

I have a very simple electrical system. It consists of two 8D batteries, three buses, and three 1-both-2-off switches. The batteries are treated as two independent banks capable of providing over 200 Ah each. There is a bus for charging sources, another for the house circuits, and one for high current loads. The high current loads are the starter, windlass, and the 3kW inverter. Each switch connects to one of the buses and the two battery banks. The high current switch opens the alternator field current circuit before it is switched to the off position. This is to protect the alternator diodes from high voltage spikes when the alternator load is removed.

There is no starter battery. As was pointed out above engine starting requires only about 1 Ah. Thus, I can't imagine how both battery banks could be so discharged that they couldn't provide 1 Ah to start my little old 35 hp engine.

Also, to the best of my knowledge, no intelligent charge controller is designed to charge with a load attached. That is why I configured this setup to allow for the isolated/unloaded charging of either battery bank.

This setup provides redundant power sources combined with maximum realtime configurability. So when getting underway one battery is set to the house bus while the other battery is set to the high current loads. This keep engine starting and windlass operation from creating a low voltage condition on the house bus which some of the electronics might not like. And as stated above, the battery not connected to the house bus can be charged as rapidly as the charging source and the battery will allow. Once the unloaded battery is charged, the charging source can be switched to reduce the current draw on the house battery. It is even possible to configured this setup as a single power source that is being charged while connected to all of the onboard loads. Also, as unlikely as it maybe, if one of the batteries were to fail, it being isolated, it would not affect the health or operation of the other battery.

Oh, don't forget that there are a number of portable battery boosters available for starting cars. These units have pretty small battery's yet are capable of starting much bigger engines then found in most cruising boats.

[cal40john]

Originally Posted by msponer

The Echo Charger is just a relay. It does not adjust the voltage, so you can't use it to mix batteries of different types.

The "sealed VRLA" thing is also off, but ... I don't want to get into a recursive conversational loop on disconnected trivia. a recursive conversational loop on disconnected trivia. a recursive conversational loop on disconnected trivia. a recursive conversational loop on disconnected trivia. a recursive conversational loop on disconnected trivia.

Haha

Please explain to me how a relay limits current to 15 amps and limits the maximum output voltage to 14.4 volts just like the EchoCharger?


Some trivia from:
http://www.xantrex.com/documents/Acc...204-01-01).pdf

The maximum charge current is 15 amps when the
starting battery is 1/2 volt to 1 volt DC less than the house battery.

The Digital echo-charge is a voltage-follower, following the three-stage
charge modes of the Freedom Charger. This method protects the starter
battery from over-charging and ensures a long life for the battery. If using
another charge source, the Digital echo-charge will follow the charge
stages of the source. Refer to the source’s Owner’s Manual for charge
modes.

When the input voltage is 13.0/25.5 volts DC or higher, echo-charge
automatically switches ON. The LED glows a steady green. When the
input voltage is lower than 13.0/25.5 volts, the echo-charge automatically
switches OFF, and the LED blinks green. The output voltage of echocharge
is limited to 14.4/28.8 volts. When it reaches 14.4/28.8 volts, the
charge current will decrease, maintaining a float condition. The starter
battery will be fully charged without overcharging.

If the input voltage is above 14.4 volts (or 28.8), output will be limited to a
maximum of 14.4/28.8 volts.

[Kettlewell]

Quick two points as to why I like the dedicated starting battery that does nothing else:

1. When I wake up in the middle of the night and I realize I am rapidly dragging towards the reef for some reason I want to be able to turn the key and have the engine go no matter what. I don't want to have to flip switches in the dark if for some reason the house bank is low, or for that matter even have to think about what position switches are in. I just want it to start.

2. Having a fully charged, dedicated starting battery prolongs the life of your starter and prevents voltage drops in your electronics circuit too. A sure way to kill your starter is to feed it low votage all the time, which often happens if you use a depleted house bank to start your engine.

[Kettlewell]

I've found that the Blue Sea Systems #6006 ON-OFF switches are great. Low cost, very robust, small, and can be flush or face mounted.

I went over to Blue Seas Systems to take a look and I noticed they also have these three-switch set ups designed just for this purpose.

Here's another neat solution from the folks at Blue Seas. By the way, I have nothing to do with them, other than using some of their equipment.

[msponer]

Originally Posted by cal40john

Please explain to me how a relay limits current to 15 amps and limits the maximum output voltage to 14.4 volts just like the EchoCharger?

There are N reasons why the sky is blue. Each reason is completely true at it's level of abstraction, and somewhat false or ambigious or meaningless if you look one level deeper. A recursive trivia conversation is one in which each person says "No, you're wrong, the sky is blue because of reason N+1". Which is strictly true, but sophmoric because it ignores that there are multiple levels of understanding reality. And it doesn't do much except wind people down to whatever limit of N the know, with the max(N) person feeling like they've accomplished something.

So let me just play this forward, and calculate Pi at the same time:
- LOL, Pi is 4, and echo charger is awesome, I can connect different kinds of batteries together and they magically charge at the right voltage.
- No, pi is 3, and you can't do that, echo charger is just a relay.
- No, pi is 3.1, and echo charger is more than a relay, it's got control circuitry on it.
- No, pi is 3.14, and control circuitry still doesn't mean that "pi is 4" up there can use it as a 12 volt battery charger to charge an arbitrary "sealed VRLA battery" from an AGM battery. I didn't go all nerdy on him because he isn't even throwing around words precisely.
- No, pi is 3.141, and it's more than "just a relay with control circuitry", because it's a PN 42021 relay with this spec sheet on this circuit that limits the current. It of course limits current by dropping the output voltage, so you are wrong, it does adjust the voltage. And sealed VRLA is a super set of AGM and Gel, and is perfectly valid statement.
- No, pi is 3.1415, and the current limiting function still does not mean that it's can be used to combine arbitrary batteries, only that it won't destroy with itself if the charged battery is flat and eats more 15 amps. And AGM and Gel both have different charging voltages, so in the context of charging it's weird to group them together under VRLA. For currents less than 15 amps the high voltage will be the same.
- No, pi is 3.14159, and ...

So... I feel it's a bit boring, it's some weird ... loop within our nerd brains where we find it compelling that "someone on the internet is wrong" (which is a red flag for me, cognitively, a kind of personal Godwin's law to just back away) and that makes us want to cut and paste in spec sheets and go tit for tat, rat a tat tat, deeper and deeper until we end up with ... wondering how we even got there, and what the point was.

Oh, the point is that the manual is written in an unclear way that has made someone think they can charge arbitrary batteries together. I was hoping to communicate that, but... don't want to go all max(N) talking about the circuit inside Echo Charger if those N+ details don't change that.

[btrayfors]

Whew! I know there's wisdom in there somewhere, but it's essence escapes me :-)

Actually, it's quite simple...and, at the first level of thought.

1. The EchoCharge is NOT a relay.

2. The EchoCharge is a voltage-follower device, that is, it outputs essentially the voltage input to it.

3. The EchoCharge has certain non-adjustable cutoffs: one for low voltage and one for high voltage. It won't operate below 13.0VDC and it won't pass voltage greater than 14.4VDC. BTW, it does not cut off if input voltages are greater than 14.4...it just limits the output voltage to that level.

4. The EchoCharge can handle a maximum of 15A pass-through. Unlike the more expensive and adjustable DuoCharge, however, it does not cut off with higher amperages, it just limits the pass through amperage to 15A. Actual amperage flow will be determined by the SOC and acceptance level of the secondary (e.g., starting) battery given the applied voltage.

5. The EchoCharge can be used with certain batteries having a similar charging profile. Flooded and AGM batteries have practically identical charging profiles, so no problem mixing them. There could be a problem mixing gels, though, since they should not be charged at voltages as high as flooded or AGMs.

What's so hard to understand?

Bill

[Cheechako]

Originally Posted by msponer

There are N reasons why the sky is blue. Each reason is completely true at it's level of abstraction, and somewhat false or ambigious or meaningless if you look one level deeper. A recursive trivia conversation is one in which each person says "No, you're wrong, the sky is blue because of reason N+1". Which is strictly true, but sophmoric because it ignores that there are multiple levels of understanding reality. And it doesn't do much except wind people down to whatever limit of N the know, with the max(N) person feeling like they've accomplished something.

So let me just play this forward, and calculate Pi at the same time:
- LOL, Pi is 4, and echo charger is awesome, I can connect different kinds of batteries together and they magically charge at the right voltage.
- No, pi is 3, and you can't do that, echo charger is just a relay.
- No, pi is 3.1, and echo charger is more than a relay, it's got control circuitry on it.
- No, pi is 3.14, and control circuitry still doesn't mean that "pi is 4" up there can use it as a 12 volt battery charger to charge an arbitrary "sealed VRLA battery" from an AGM battery. I didn't go all nerdy on him because he isn't even throwing around words precisely.
- No, pi is 3.141, and it's more than "just a relay with control circuitry", because it's a PN 42021 relay with this spec sheet on this circuit that limits the current. It of course limits current by dropping the output voltage, so you are wrong, it does adjust the voltage. And sealed VRLA is a super set of AGM and Gel, and is perfectly valid statement.
- No, pi is 3.1415, and the current limiting function still does not mean that it's can be used to combine arbitrary batteries, only that it won't destroy with itself if the charged battery is flat and eats more 15 amps. And AGM and Gel both have different charging voltages, so in the context of charging it's weird to group them together under VRLA. For currents less than 15 amps the high voltage will be the same.
- No, pi is 3.14159, and ...

So... I feel it's a bit boring, it's some weird ... loop within our nerd brains where we find it compelling that "someone on the internet is wrong" (which is a red flag for me, cognitively, a kind of personal Godwin's law to just back away) and that makes us want to cut and paste in spec sheets and go tit for tat, rat a tat tat, deeper and deeper until we end up with ... wondering how we even got there, and what the point was.

Oh, the point is that the manual is written in an unclear way that has made someone think they can charge arbitrary batteries together. I was hoping to communicate that, but... don't want to go all max(N) talking about the circuit inside Echo Charger if those N+ details don't change that.

I want some of what he's smoking!

[tuberider]

hey mikefossl, on your wiring schematic, why are you jumping the positives on the 6 volt terminals of your house bank. i could see if you were tapping for a 6 volt load, but in the drawing the 6volt positive jumpers aren't doing anything.

[cal40john]

You make a statement that someone is wrong without explanation or backing it up, and you finish with attitude at the end. I didn't help the process with my attitude in my reply. Now you give an explanation that belittles the reader and is wrapped up in so much crap that it's difficult to see if you make any sense at all. I don't pay attention to advice given unless it comes with an explanation that makes sense, you want people to listen to you without explanation apparently because it is below you to explain. I guess I won't be paying attention to you and I'm not going to bother wading through another obfuscated condescending explanation.

Yes you're right in the sense that you probably don't want a Gel battery on the output of an Echocharger, but who puts a Gel in as a start battery?

Originally Posted by msponer

There are N reasons why the sky is blue. Each reason is completely true at it's level of abstraction, and somewhat false or ambigious or meaningless if you look one level deeper. A recursive trivia conversation is one in which each person says "No, you're wrong, the sky is blue because of reason N+1". Which is strictly true, but sophmoric because it ignores that there are multiple levels of understanding reality. And it doesn't do much except wind people down to whatever limit of N the know, with the max(N) person feeling like they've accomplished something.

So let me just play this forward, and calculate Pi at the same time:
- LOL, Pi is 4, and echo charger is awesome, I can connect different kinds of batteries together and they magically charge at the right voltage.
- No, pi is 3, and you can't do that, echo charger is just a relay.
- No, pi is 3.1, and echo charger is more than a relay, it's got control circuitry on it.
- No, pi is 3.14, and control circuitry still doesn't mean that "pi is 4" up there can use it as a 12 volt battery charger to charge an arbitrary "sealed VRLA battery" from an AGM battery. I didn't go all nerdy on him because he isn't even throwing around words precisely.
- No, pi is 3.141, and it's more than "just a relay with control circuitry", because it's a PN 42021 relay with this spec sheet on this circuit that limits the current. It of course limits current by dropping the output voltage, so you are wrong, it does adjust the voltage. And sealed VRLA is a super set of AGM and Gel, and is perfectly valid statement.
- No, pi is 3.1415, and the current limiting function still does not mean that it's can be used to combine arbitrary batteries, only that it won't destroy with itself if the charged battery is flat and eats more 15 amps. And AGM and Gel both have different charging voltages, so in the context of charging it's weird to group them together under VRLA. For currents less than 15 amps the high voltage will be the same.
- No, pi is 3.14159, and ...

So... I feel it's a bit boring, it's some weird ... loop within our nerd brains where we find it compelling that "someone on the internet is wrong" (which is a red flag for me, cognitively, a kind of personal Godwin's law to just back away) and that makes us want to cut and paste in spec sheets and go tit for tat, rat a tat tat, deeper and deeper until we end up with ... wondering how we even got there, and what the point was.

Oh, the point is that the manual is written in an unclear way that has made someone think they can charge arbitrary batteries together. I was hoping to communicate that, but... don't want to go all max(N) talking about the circuit inside Echo Charger if those N+ details don't change that.

[msponer]

Sorry, I don't mean to be offensive or cause a nerd fight.

Yes, calling it a relay is an oversimplification. It is of course a voltage following device.

I felt like the gentleman who was using it to mix his "AGM and VRLA batteries" is misunderstanding what the device is, and possibly doing something wrong with it (depending on what kind of VRLA battery he has), but I did not feel like going into a long and technical exhaustive explanation. My gut feeling is that if someone does not understand the manual, then I have little confidence my ability to use the right words to get them to understand it from me better. So I thought the idea of "think of it as a relay" is concise and more helpful, even if it... is wrong on another level to people who know more.

I struggle with finding the balance between communicating in a direct and concise way that is what I feel is immediately understandable to the person I am talking to while also being considered correct to everyone else who could possibly read it. I sometimes feel like the best manners are to communicate on whatever level the conversation is at, but will stop doing that here, because it side tracked the conversation and added noise.

So that's what my whole meta conversation was about, that struggle or nuance within online manners. I did not mean to be rude or anything like that, I was mostly thinking about it as a kind of funny thing, like "Oh, look at the funny direction this conversation could go next." Within the other domains I think in, the idea that there are multiple levels is taken as a given, and it's usually considered best to be at the minimal level of abstraction to solve a problem. But I was was very wrong and misjudged the problem from "try to get someone to realize they might be making a mistake" to that plus "don't say anything that could be seen as an over simplification by other people."

I also apologize for being self indulgent with tangents about the meta conversation, cognitive styles, and our evolving culture and manners online, I need to keep those discussions elsewhere and not be off topic in a sailing community. Here they are just noise, especially because the playful and dispassionate tone I intended did not come through.

So... I'm sending happy vibes. Yes. You are right.

[hellosailor]

Pat-
"2 [house] banks are recommended" WERE recommended. No longer are.
The new logic is that because batteries last longer when you don't cycle them as deeply, you put in the biggest house bank you can fit/afford. One house bank. And then you discharge cycle that as gently as you can, i.e. 30% before recharging, 50% if you must.
Then you have one separate SLI battery, small, cheap, easily replaceable, as your dedicated starting battery, used only for starting.
That way your starting battery is safely isolated, and if you kill it, you've still got that whopping big house bank to start from. The starting battery is no budget killer, and the house bank gets to be one big bank instead of two smaller banks, so it is discharged only half as far, and may last twice as long.
Charge cycling your house battery bank 30% instead of 50% may double or triple the battery life, depending on whose numbers you believe. Running it to 50% instead of 80%, easily doubling ot tripling the life. You wind up being able to store and use more kilowatts per dollar spent on battery, so the "new logic" about one house bank and one starting battery makes good sense.
The starting battery can be an SLI (starting) for economy, or a deep cycle that has enough power to start your engine, is you prefer the security of another deep cycle power source.