Wiring a DC-DC Xantrex echo charger

[KREW2]

To power my new windlass I am going to use a separate battery charged from a Xantrex echo charger, but I don't understand what seems to be a simple wiring diagram http://www.jgtech.com/pdf/Echo_Charge_Manual.pdf
It shows only a positive connection to the windlass battery, the only negative connection will be from the windlass via the control box and circuit breaker, so, do I have to run a negative to the windlass battery from the donor battery.

 

[Playtime]

To power my new windlass I am going to use a separate battery charged from a Xantrex echo charger, but I don't understand what seems to be a simple wiring diagram http://www.jgtech.com/pdf/Echo_Charge_Manual.pdf
It shows only a positive connection to the windlass battery, the only negative connection will be from the windlass via the control box and circuit breaker, so, do I have to run a negative to the windlass battery from the donor battery.

I think the confusion is that the Xantrex manual is assuming the batteries are close together and the negatives will all be commoned up.

If the windlass battery is in the bow, several metres away, you will need a negative feed to the windlass battery as well as a postivie feed. The negative should also be connected to the ship negative as should the Xantrex negative.

 

[cimo]

correct.
the "to ground" lead in the diagram (page 8?) connects to both battery negative posts. (the illustration makes a pretty poor wiring diagram).
hang about as there are a few folks here that have working knowledge of these series regulators & may be able to share their expreiences.
rgds
c

ps - oops - didn't see you there while I was posting playtime.

 

[KREW2]

Playtime thanks very much.
The way I see it I can ground the DC-DC charger to the donor battery, and as it is part of the main battery bank it will also be suitable to run a negative to the windlass battery.

 

[Stu Jackson]

Simply put, ALL the negatives are the same, regardless of which battery they come from because they all go back to the engine. Find one and use it. It's that simple.

 

[VicS]

Yes there must be a common negative connection between both batteries and the windlass which must be cable as heavy as that used for the positive connections as it will carry the same current* . The Xantrex "ground" connection should also be connected to the negative

*That means both cables from the windlass battery to to the windlass must be capable of carrying the windlass current even if the connection between the two battery negatives needs only to be as heavy as the Xantrex positive connections.

I see they recommend 16 AWG for the Xantrex but 12 AWG to extend them. However they say avoid long connections. In your case you will have long connections so it would be advisable to ignore these recommendations and calculate what gauge wire is required for the lengths of the cable runs you will have and the current output of the Xantrex. I suspect that could be as heavy as 8 AWG. It will if the distance between the batteries is 20 ft.

 

[halfway]

I'm sorry but that unit should not be used with long wires.

The reason is that it is a follower type, so it is sensing both input and output voltages.

So if you mount it next to the house battery the output (at the unit) will be the right voltage to charge the bow battery, but after the drop of the long wires it will be too low. Even drops of 0.2v will significantly limit the charging.

If you mount it next to the bow battery then it will sense the house battery after a long wire. So will never see the high charge voltages produced by the boat charger. This is because the long lines will drop a voltage as soon as it starts charging.


Normally, for a follower type used over long distances, you need a separate set of sense leads (that carry no current) on one or other of the input or output.


If it is a self controlled step charger, (not a follower) then you do not need sense leads but must mount it in the bow.


Sorry.

(All above is true, unless the unit works by shutting down periodically, so that it can sense the two batteries correctly. But then you start getting into fights between the chargers. Assuming that the manual says explicitly that long wires are wrong I assume it is a constant sense system)

 

[William_H]

I'm sorry but that unit should not be used with long wires.

The reason is that it is a follower type, so it is sensing both input and output voltages.

So if you mount it next to the house battery the output (at the unit) will be the right voltage to charge the bow battery, but after the drop of the long wires it will be too low. Even drops of 0.2v will significantly limit the charging.

If you mount it next to the bow battery then it will sense the house battery after a long wire. So will never see the high charge voltages produced by the boat charger. This is because the long lines will drop a voltage as soon as it starts charging.


Normally, for a follower type used over long distances, you need a separate set of sense leads (that carry no current) on one or other of the input or output.


If it is a self controlled step charger, (not a follower) then you do not need sense leads but must mount it in the bow.


Sorry.

I would have to disagree to a degree with the logic. Any regulated charging system which senses the voltage at the charger end of a long wire (resistance) acts the same way. The resistance reduces the voltage at the battery end for a given current but because the voltage to the battery is lower so is the current hence so is the voltage drop. It all comes to a happy medium with a little less current but voltage sensing function of the staged charger should be still OK.
So I would suggest yes use the long wires you need. make them as heavy as practical. Then don't worry. olewill

 

[Stu Jackson]

Why not engineer it properly? The echo charger is simply a current limiting (15A max) relay. The relay closes when a threshold voltage is met (as when charging takes place from any source over the threshold, usually 13.2 V +/-, and opens again at 12.8V when charging source is removed to separate the banks), it just "operates" on voltage going UP and the voltage other "coming down." The "follower" type mentioned means it follows the charge regimen of the main charging source. Vic is right, find out the current and size the wire accordingly.

 

[halfway]

Willian_H is right in describing how it will get to a equilibrium BUT the issue is whether you want it to fall back to such a slow charge.

Yes, it will eventually charge the battery, but it will take a long long time.

---

It is the same as using a say Victron charger in the aft of a boat charging a battery bank 10m away. The voltage drop at 50A using 1AWG wire is 0.4v

The voltage the charger creates at its terminals is say 14.4v, therefore, the battery would only see 14.0v so would take an age to charge.

However if you wire the two sense leads through the boat the charger now outputs 14.8v and the battery sees its full bulk charge requirement.

The above scenario was a real boat on a town quay in Greece when the poor new owner of the wonderful big boat was running his generator for 8 hours a day to charge the batteries! He was at the end of his tether! As his neighbour, I was a little disturbed. So in the interest of peace I fixed his boat.

---

This is similar to the requirement of the bow battery situation, where an owner will find that when going cruising for a week that the limited 1 hour a day of engine use will not maintain the bow battery. But you don't normally know until the wind blows up one day and the windlass stalls under the low charge situation.

---

If however you put in oversized wires, that minimizes the voltage drop, you might as well have just fitted a VSR! Once the wires are large enough to handle the largest charge source there is no advantage. This would allow you to fit an override and let the windlass run off the main house battery, and alternator, as well as the bow battery.

---

So as I said earlier, this unit is not appropriate for the requirements of a bow battery.

 

[neale]

I'm sorry but that unit should not be used with long wires.

The reason is that it is a follower type, so it is sensing both input and output voltages.

So if you mount it next to the house battery the output (at the unit) will be the right voltage to charge the bow battery, but after the drop of the long wires it will be too low. Even drops of 0.2v will significantly limit the charging.

If you mount it next to the bow battery then it will sense the house battery after a long wire. So will never see the high charge voltages produced by the boat charger. This is because the long lines will drop a voltage as soon as it starts charging.

I was told to mount mine as near to the middle of the two batteries as possible. I have achieved that with the Xantrax mounted almost exactly mid ships, (the battery bank is right at the stern), and it seems to be working perfectly.

 

[halcyon]

Why not engineer it properly? The echo charger is simply a current limiting (15A max) relay. The relay closes when a threshold voltage is met (as when charging takes place from any source over the threshold, usually 13.2 V +/-, and opens again at 12.8V when charging source is removed to separate the banks), it just "operates" on voltage going UP and the voltage other "coming down." The "follower" type mentioned means it follows the charge regimen of the main charging source. Vic is right, find out the current and size the wire accordingly.

Is this not just a 15 amp DC-DC switchmode step-up converter, starts up at 13 volt, and gives a 14.4 volt output.

The problem is the low output current, against required charge rate, against engine run time. If this is adiquate for the demands placed on the battery, then the system may work ok. But it would need the bow battery voltage monitored, to avoid a low battery with limited recharge.

With a VSR system you have flexability with battery charge priority, and you can remotely link the service battery with a low bow battery to help share the load.


Brian

 

[halfway]

neale: I'm sorry but no charger without sense leads can work "perfectly". However they can work adequately over short distances.

The guy in Greece, with his new boat, thought it worked perfectly otherwise he would not have left to go long term cruising.

As for putting the unit in the middle. Assuming a high efficiency, the current both sides are similar. Since it is a follower, the voltage sensitivity is the same both sides. Therefore you achieve nothing by its position.

Look at the evidence:
1. The makers manual explicitly states not to use long wires.
2. Two competitive products that are recommended for this exact task, have sense wires. Their use is described explicitly in the manuals.
3. An example is given of a similar, but simple, real life situation showing how life was getting impossible in none marina situations for a cruiser.


However, it is clear from reading this, and other posts on the subject, that these people running the companies are totally deluded and wish their companies to fail as they over-engineer their products. But then they might be designing for real boats, and the majority only use their windlass just for lunch stops between overnight marinas. So go ahead, and use units outside their design envelope, but by definition you will not find out its limitations until you are far from help.

 

[neale]

I was not using the term 'Perfectly' in the literal sense, really meaning it seems to work fine.

The instruction to fit it the way I have came from someone who I perceive as a bit of an expert in marine electronics. I am in no position to say whether it is right or wrong, only that the advice came from a good source and it seems to work.

I guess there is also some clarity needed on what 'Long' really means. Mine is about 3 metres from each battery. Is this long?

I guess I could take some voltage readings at both batteries during charging and running and see what exactly I am getting at the bow battery, but bearing in mind my bow battery is also running a 2kw bow thruster as well as windlass, if the Xantrax didn't perform I would have expected to have seen some problems by now.

There are always a number of ways of solving a problem, some better than others and some more expensive that others. For what I paid and for how it has performed, I am 'Perfectly' happy.

 

[Maine Sail]

Personally I would not choose an Echo Charger for that application. A Balmar Duo Charger or similar with higher amp output capabilities and voltage sense capabilities or VSR/ACR would probably be my choice. My ideal choice would be to run the windlass off the house bank and run the appropriate ga wires to the bow if that is possible.

It may work depending upon bank size and demand but the odds are probably stacked against you, as the Echo works on voltage differential to determine amp output, any added voltage drop could potentially cause it to not work as designed.

If you used an 85 amp windlass, for four minutes each time you used it, and used it only twice per day, you would be burning about 11.3 Ah's day. On a 100 Ah bank this still leaves the battery at close to 90% SOC, with a bigger bank you'd have a higher overall SOC. Banks are accepting little current at 90% SOC depending upon size in total Ah's.

If the battery is a wet cell it will be accepting low current in teh above scenario and your limiting factor will be long acceptance time to get the bank back to 100%. If however you have to do multiple sets or anchor multiple times per day you could draw down this bank to a point where the 15A max output of the Echo was just not enough especially with any volt sensing issues.

From Xantrex:

"Select a location that is within two feet of the house battery and within two feet of the starter battery, for maximum charging current."


Avoid using long connection wires. The longer the wires, the less current will flow and the longer it will take to charge the starter battery.

 

[KREW2]

Thanks for the tip, but it does say if you want to extend the cable use 12 guage wire.
Wish I understood how these things worked, as I don't, I just have to go by others experiences.

 

[Stu Jackson]

Wish I understood how these things worked, as I don't, I just have to go by others experiences.

Why not read the manual? Really, that's how I learned: pages 1 & 9 of 18 PDF page in the Echo Charge manual from the Xantrex website:

The Xantrex Digital echo-charge is specially developed for charging an
auxiliary battery with FreedomTM or Fleet Power® Inverter/Chargers or with
any charging source. The Digital echo-charge automatically switches ON
and OFF, charging a starter or auxiliary battery without affecting the main
house battery bank. 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 designed to work on 12 VDC or 24 VDC systems.
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.
No load current drain on the house bank is less than 50 milli-amps.
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.

This also, BTW, supports Maine Sails ideas, and encourages the use of the house bank for the windlass power source. Alternatively, one could use a combiner which is a full flow (no limit to the amperage) relay, but is still limited by the battery acceptance, and therefore just as problematic. The difficulty of installing a separate battery seems to be equaled by running heavier gauge wires, so why not simply run the heavier wires?

 

[KREW2]

Why not read the manual? Really, that's how I learned: pages 1 & 9 of 18 PDF page in the Echo Charge manual from the Xantrex website:

The Xantrex Digital echo-charge is specially developed for charging an
auxiliary battery with FreedomTM or Fleet Power®

The Digital echo-charge is a voltage-follower, following the three-stage
charge modes of the Freedom Charger, the Digital echo-charge will follow the charge
stages of the source. Refer to the source’s Owner’s Manual for charge
modes.
no load current drain on the house bank is less than 50 milli-amps.
[/I]

I have read the manual, bits like the above mean nothing to me.
However I did understand the sentence " #12 gauge wire, if an extension is needed." and 12 guage more than covers the run I wish to do. The bit that confuses me is the unit has 16 guage cable wired into it so the first part of the run is going to be with undersized cable. I'm thinking on the lines of "chain and weakest link"

 

[Stu Jackson]

Wrong analogy. It's more like the smaller neck of a funnel. Slows the water down but lets it pass through. Not an issue in calculating total voltage drop for the entire wiring run.

As far as learning, you really do need to learn this stuff, if only for your own safety and that of your family and friends. Oh, and your pocketbook, too.

Yes, it takes some time, but there are only three things in electricity you need to know: volts, amps and wiring connections. If you learn those things, then battery care becomes commonsense and you start saving money because you learn to take care of the stuff you buy.

Any basic electrical book will suffice.

Your charger should charge in three stages. Suggest that you read the Ample Power Primer at www.amplepower.com, Tech tab. That explains what batteries need to charge properly, in plain, understandable English (US, though . It also covers amps and volts.

This discussion was also held elsewhere, so you're not alone: http://www.sailnet.com/forums/electrical-systems/60009-best-way-learn-electrical.html

All the best, Stu

 

[cimo]

hello krew2
you're post generated alot of answers here!

understand it or not, the manual is somewhat economical with it's information. not knowing you're origional decision making process, my only constructive input would be to suggest perhaps to re-visit the reasons.

The echo charger isn't really suited to long cable runs, and you will not get the expected effectivness. If you go ahead, placing the echo midway as already mentioned makes sense in ths regard and it is hinted at in the liturature.

I'm with stu on this one, running the windlass from your current battery bank (with the engine on) is what I'd do too. others have provided cable calculations. I would fuse at around 1.5 times working current, to allow for windlass snagging (you would need to carry spare fuses also, as the motors short circuit current will be multiples of the operating current) & make sure your cable current rating is greater than your fuse rating.

good luck whatever road you take.