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Author Topic:   Auxiliary Battery Charging Kit for E-TEC
jimh posted 07-18-2010 04:08 PM ET (US)   Profile for jimh   Send Email to jimh  
I just installed the AUXILIARY BATTERY CHARGING KIT, PN 5006253, on my 2010 E-TEC 225-HP Engine. This kit is designed for use on 2005 and newer Evinrude E-TEC engines from 115-HP to 250-HP. The retail price is about $110.

The kit comes with illustrated instructions for installation. Installation took me about two hours. Most of the time was spent rigging the new cable through the lower engine cover grommet, through my existing rigging cable flexible enclosure, and through the transom rigging tube on my boat's full transom. All of these passages were already filled with cables, and it was a tight fit to accommodate another cable. On a boat with an notched transom and open rear cockpit, installation would be much faster.

The electrical basis for the AUXILIARY BATTERY CHARGING output is quite interesting and deserves some further mention. The electrical system on the E-TEC is substantially different from older outboard motors. The principal difference is that the permanent magnet alternator is designed to produce 55-volts DC output. Another significant difference is the 12-volt battery charging output is derived from the primary 55-volt circuit by use of a modern electronic voltage regulation system which uses a pulse-width modulation technique. This produces a very efficient voltage conversion, and the regulation of the 12-volt system does not tend to produce a great deal of wasted energy in the form of heating of a heat sink, as was typical of older voltage regulators. All of the heavy-lifting in the battery charging voltage regulation is accomplished in the engine management module, or EMM. In the larger motors which can provide an auxiliary charging output, there are actually already in place two battery charging circuits in the EMM. In the normal configuration these two circuits operate in parallel, each providing about 25-amperes of charging current at maximum, for a combined total of about 50-amperes. When you add the AUXILIARY BATTERY CHARGING output, you re-wire one of those charging outputs to be routed to an isolated battery. By very good design and engineering, Evinrude has already provided all the connectors you will need, so the re-wiring is just a matter of moving some cables around and changing where they connect.

One of the charging outputs from the EMM is hard-wired into the primary power distribution of the E-TEC motor, but the second EMM charging output is provided on a connector. Normally a mating connector routes this output back to the primary power distribution in stock configuration. When you add the AUXILIARY BATTERY CHARGING output, this connection is broken, and the second battery charging output is simply connected to a new cable via the appropriate mating connector. The new cable is run out from under the engine cowling, where it can attach to a second battery. When this has been done, the E-TEC now splits its total charging output: 25-amperes remain for the engine and its primary power to charge the battery connected to the engine, and 25-amperes are available from the new output for an isolated battery. The old connector which routed the charging output to the primary power distribution is simple capped up and left unconnected. This also allows the auxiliary charging option to be easily removed, if desired in the future.

Some boats use an automatic combining relay (ACR) or a voltage sensitive relay (VSR) to accomplish the automatic charging of a second battery from an output motor, but such a configuration results in two batteries being wired in parallel and thus charged in parallel. The advantage of the AUXILIARY BATTERY CHARGING output of the E-TEC is that the two batteries do not need to be placed in parallel, and their loads remain isolated from each other. They are charged independently. They are never in parallel and the loads are never in common.

Before investigating the AUXILIARY BATTERY CHARGING output option, I looked at using an ACR or VSR as an alternative. I found the cost was higher for that approach, the wiring was more complicated, and the operation was not as desirable. Although a typical ACR may only cost about $75, if installed with all of the recommended associated wiring components, including quite a number of fuses, and taking into account the additional wiring, lugs, terminals, and so on, that would be needed, the total cost of the ACR installation was far greater than the cost of the AUXILIARY BATTERY CHARGING kit. (For an analysis of the cost of adding an ACR see my article where I found that the ancillary components needed to install an ACR cost more than the ACR.) The ACR adds several additional conductors and circuits to the primary power distribution wiring. And in operation, the second battery only gets charged once the primary battery is at full-charge. There can also be problems with starting when the batteries are connected in parallel. This could cause voltage spikes to reach electronics--one of the primary reasons for having separate batteries in the first place. Since the AUXILIARY BATTERY CHARGING kit costs less, is much simpler to install, and provides better operation, I saw no reason not to take advantage of it.

The only disadvantage of installing the AUXILIARY BATTERY CHARGING kit is you will reduce the charging output to the primary power distribution and connected battery to 25-amperes. It is my experience that one seldom needs a 50-ampere charging output. Most batteries would rather not be charged at a rate as high as 50-amperes.

jimh posted 09-12-2010 03:56 PM ET (US)     Profile for jimh  Send Email to jimh     
To follow up on this topic, after I installed the Auxiliary Battery Charging Kit on my E-TEC, I also made modification to the primary power distribution switch on my boat. Previously the boat had the very common OFF-1-ALL-2 type of battery switch in which a single output is switched between OFF or one or both of the batteries. I replaced this switch with a new primary battery distribution switch of a different design, a BLUE SEA SYSTEMS 5511e.

The BLUE SEA SYSTEMS 5511e switch is a dual circuit battery switch. It has only three positions: OFF-ON-EMERGENCY. The switch has separate circuits for two batteries, one nominally the engine starting battery and the second the boat house battery for non-engine loads. The two batteries are kept isolated at all times unless the switch is put into the EMERGENCY position, when the batteries are paralleled.

Installation of the switch was very easy because the four mounting holes are arranged to match the previous switch's mounting holes; nothing new had to be drilled to mount the switch. I did have to get longer mounting bolts, as the new switch sits higher than the old PERKO switch.

The change to this isolating switch was made to keep the boat electronics from being affected by engine starting in normal operation. I can have my GPS receiver-chart plotter-SONAR unit running, and when I start the E-TEC engine there is no effect on the battery voltage to the electronics. Nothing reboots due to a voltage sag. Also, at night, if we need to run the cabin lights for several hours, all of the drain comes off the house battery, and the engine starting battery is not affected in the least.

I made this change prior to our 8-day cruise to remote Isle Royale National Park, where we anticipated we would not have access to shore power at most of our overnight docks or anchorages. I did not want to have to worry about running down the starting battery if we left the cabin lights on too long, or have the chart plotter reboot at every engine start.

On the trip we probably averaged only one engine start per day, so the engine starting battery got plenty of recharging. The house battery also stayed fully charged, thanks to the auxiliary charging output from the E-TEC. This new system is very simple to operate, and there are not a lot of extra components and wiring as would have been necessary if I used an automatic combiner relay with starting isolation. With the Auxiliary Charging Kit and the 5511e battery switch, there is nothing to operate. During our entire cruise we just left the battery switch in the ON position, and we had confidence we would always have a fully charged battery for engine starting while being able to draw as much power as we wanted from the house battery.

andygere posted 09-15-2010 03:31 PM ET (US)     Profile for andygere  Send Email to andygere     
Good article Jim. Had I known I'd be replacing my motor with an E-TEC at the time I rewired my battery system using a VSR and switch cluster, I'd have gone this route. Much cleaner, cheaper and it takes advantage of some nice built-in capability in the E-TEC charging system. The use of the Blue Seas 5511e provides instant "jump start" capability from the house battery, which was one of the features I was looking for when I installed my system. Do you have any photos of the kit, switch and completed installation?
jimh posted 09-15-2010 08:36 PM ET (US)     Profile for jimh  Send Email to jimh     
I will try to take a few pictures of the installation this weekend and append them.

The E-TEC Auxiliary Battery Charging Kit is simplicity at its best. The kit consists of:

--a heavy-gauge paired cable with one end prepared for connection to a battery and the other end fitted with a special connector

--a cap fitting to fit the specialized connector that will become unused when the above cable is installed.

As I described earlier, installation is very simple. After you get the new cable installed, you just unplug the existing connection in the electrical system, plug in the new cable, and add the cap to seal off the old cable. The other end just connects to the battery.

I will also draw up a detailed sketch of how the whole system is wired. In electrical circuitry one good sketch is worth twenty paragraphs of text.

jimh posted 09-15-2010 10:04 PM ET (US)     Profile for jimh  Send Email to jimh     
Primary Battery Distribution on CONTINUOUSWAVE

Schematic diagram of  primary electrical distribution on boat with two batteries.


1: Engine cranking battery; Interstate Group-24 flooded cell 1,000-MCA.

2: House battery; Interstate Group-24 flooded cell 1,0000-MCA, but will be changing to AGM combination deep-cycle and cranking, probably SEARS Marine Platinum.

CB1: Circuit breaker, 50-ampere, for distribution to electrical panel at helm console, original with boat, E-T-A brand, push-pull actuator.

F1: Fuse, 10-ampere, for distribution to aft sump pump control panel for pump in cockpit live well.

F2: Fuse, 50-ampere, integral with electrical harness from auxiliary charging output from E-TEC engine.

F3: Fuse, 5-ampere, integral with electrical harness from AC-operated battery charger for positive lead, cranking battery.

F4: Fuse, 5-ampere, integral with electrical harness from AC-operated battery charger for positive lead, house battery.

F5: Fuse, 5-ampere, integral with electrical harness from AC-operated battery charger for negative lead, house battery.

AC-operated Battery Charger; dual output, 120-VAC operated charger, 4-ampere charging each bank.

S1: main battery switch, BLUE SEA SYSTEMS 5511e Dual Circuit OFF-ON-EMG primary battery switch. The normal operation is for the Main Battery Switch to be in the ON position. This supplies the outboard motor MAIN harness with power from Battery-1 for cranking; after engine start this circuit supplies charging current to Battery-1. The outboard motor AUX harness supplies charging current to Battery-2 after engine start.

The Sump Pump Panel is supplied 12-volts from the HOUSE battery via F1. This permits the sump pump to run even if the main power switch is set to OFF. This allows the pump to evacuate water if the boat is left unattended, without having to leave all circuits powered.

Wiring of the primary battery circuits is done with 4-AWG or larger conductors, except the feed to the HOUSE panel is 8-AWG. The negative terminal of Battery-1 is the negative common point. (Note: this could more properly be moved to a heavy gauge bus, which would reduce the number of connections at each battery negative terminal. The bus would then become the negative common point.)

The AFT NEGATIVE BUS provides a convenient wiring point for the negative leads of several loads located in the stern of the boat. These loads receive their positive feed from switched circuits at the helm, but their negative leads return to this bus. Having this bus at the stern avoids having to run all these circuits back to the helm for the negative return. The circuits are:

--aft navigation lamp
--aft cockpit live well sump pump
--trim gauge isolated ground
--electric fuel primer pump
--aft cockpit pump control panel lamp circuit

The trim gauge isolated ground is provided to improve calibration of the trim gauge meter and isolate it from other negative return currents.

andygere posted 09-15-2010 11:49 PM ET (US)     Profile for andygere  Send Email to andygere     
Thanks for the additional detail, it's a really well designed system. The wiring for the aft sump pump is key, I wish I had wired mine that way (and that Boston Whaler would have on the originals).
Basshole posted 09-16-2010 01:18 AM ET (US)     Profile for Basshole  Send Email to Basshole     
Darn! More stuff I NEED to get ;)
jimh posted 09-19-2010 03:07 PM ET (US)     Profile for jimh  Send Email to jimh     
As requested, here is a photograph of the BLUE SEA SYSTEMS 5511e switch installation on my boat.

Photo: Blue Sea Systems 5511e battery switch installation.

The switch was mounted in the existing mounting holes used by the old switch (made by PERKO). The fasteners are stainless steel machine screws and elastic stop nuts, also called Ny-Lok nuts. Use of an elastic stop nut permits good retention of the fastener under vibration without having to torque the fastener too much. With plastic components you have to be careful not to over-tighten the fasteners and crack the plastic.

The battery positive cables have black insulation but are clearly identified as positive by marking with RED vinyl electrical tape using 3M-SCOTCH 35 vinyl electrical tape. The intelligence of clearly marking the polarity of all the battery cables seems manifestly simple, but it is astonishing how frequently this simple task is omitted, often to the financial ruin of the boat owner. The switch is out of the weather because it is under the aft deck of the boat. The actual switch terminals are somewhat exposed on the two sides and bottom where the wire can easily be passed through. Care should be taken not to make accidental contact with the terminals.

The aft negative terminal bus is mounted above the switch. The higher mounting was chosen to keep the electrical contacts far above any water that might enter the boat. Wire with BLACK insulation was used for several existing circuits. Newly added circuits have wire with YELLOW insulation. The conductor with SLATE insulation (or GRAY) is marked with a piece of black tape with a white stripe, the color code for its function as the ISOLATED GROUND of the TRIM circuit.

An original Boston Whaler DESERT TAN battery box is visible to the right. The battery box and its lid are retained by a nylon strap with stainless steel locking mechanism and safety pin known as KEVLOK hold-down straps.

jimh posted 11-02-2010 08:36 AM ET (US)     Profile for jimh  Send Email to jimh     
I should mention that the new isolated battery arrangement worked perfectly on our trip to Isle Royale National Park. While visiting the park we did not have access to any 120-VAC dock power during our eight days there. The isolated battery wiring and dual charging configuration worked wonderfully. We had no problems with engine starting. Our GPS receiver, chart plotter, SONAR, and multi-function display never rebooted during engine starting. We could read in the cabin with the cabin electrical lights without concern about drawing down the starting battery.

I am very pleased with the operation of the system. I highly recommend this approach to primary electrical distribution and battery charging.

Robert V posted 11-05-2010 06:49 AM ET (US)     Profile for Robert V  Send Email to Robert V     
Jim--Thanks for the detailed installation explanation for the auxiliary charging kit and battery switch. I am very interested in replacing my PERKO battery switch with the Blue Sea switch. Do you think this is a good idea for my 2008 205 Conquest? Thanks,


jimh posted 11-08-2010 08:10 AM ET (US)     Profile for jimh  Send Email to jimh     
Use of the Blue Sea Systems 1155e switch is best when there are two isolated charging sources available to maintain the separate HOUSE and ENGINE batteries.
Robert V posted 11-08-2010 05:09 PM ET (US)     Profile for Robert V  Send Email to Robert V     
I only have one charging source. Thanks for the answer Jim.
jasongillies posted 08-13-2012 11:54 PM ET (US)     Profile for jasongillies  Send Email to jasongillies     
Hi Jim
Can you comment on one of the connections you have in the diagram..specifically for Blue Sea Systems 5511e and E-TEC dual charge circuit

The connection from the AUX+ (of the engine) goes directly to the battery +Ve so connected all the time.

This does not isolate the engine charge circuit when the battery switch is off. This could lead to corrosion or leaking battery or someone working on engine might not notice live voltage still on engine with switch OFF.

I suggest that the AUX+ go to the switch output just as the main+ from engine but on the other circuit? So off would be OFF

I know your diagram looks like it is modified VSR circuit that connects second battery to an engine automatically but VSR would not have the engine connected constantly...The VSR opens when the engine is off...

The only think I can think of for the connection you have depicted is if the switch is turned to OFF with engine running. What could happen is with switch OFF you could see the engine charging the house circuit but no battery connected, so could see high voltages if the regulator is not smart enough to lower voltage.. Although ETEC say they could run without a battery, I dont suggest anyone trying going OFF while engine going could also damage electronics.


jimh posted 08-14-2012 12:02 AM ET (US)     Profile for jimh  Send Email to jimh     
Jason--Thanks for the comments. I will have to check the OEM instructions on how to connect the auxiliary output. Your point is a good one.
jimh posted 08-14-2012 12:07 AM ET (US)     Profile for jimh  Send Email to jimh     
In their literature for the auxiliary battery charging kit, PN352170, Evinrude says:

"Attach auxiliary battery cable to accessory battery."

That is what I have done and what I show in my diagram.

jimh posted 08-14-2012 12:13 AM ET (US)     Profile for jimh  Send Email to jimh     
In the Evinrude literature PN500785, 2010 RIGGING AND PREDELIVERY E-TEC MANUAL, on page 18 there is a wiring diagram for a single engine installation with two batteries and an auxiliary charging accessory. The diagram shows the wiring exactly as I have shown it.

It is typical that in a battery charging circuit the output lead only permits current flow in one direction, from the charging circuit to the battery. This is likely the case with the Evinrude permanent magnet alternator and regulator circuit. The battery may be connected all the time, but the battery cannot supply current to the E-TEC outboard engine via that path.

jasongillies posted 08-14-2012 01:08 AM ET (US)     Profile for jasongillies  Send Email to jasongillies     
Hi Jim
Wow prompt and detailed replay thanks. yes can see that in pre delivery manual spot on thanks


jasongillies posted 08-14-2012 01:18 AM ET (US)     Profile for jasongillies  Send Email to jasongillies     
Hi Jim
Just posing one thought for discussion.

The delivery manual for single motor two batteries as you correctly point out, shows a normal switch 1, 2, both (not like the 5511e) and it is circled on 1 indicating normal position 1 you start engine of batt1 but as switch is not like the 5511e battery 2 would never get connected to motor if you stay on 1, so the cable is connected directly to batt2 as it would not get charged.Yes?

With the 5511e switch it is different the switch has two poles connecting both circuits to each battery, so ON is on to each battery not one switch to one battery.

Yes I agree voltage back in to regulator and alternator poles should not be an issue as its an AC rectification and should not flow back in.. but strange things happen with live wires.


jimh posted 08-18-2012 02:24 PM ET (US)     Profile for jimh  Send Email to jimh     
When using a two-pole switch like the BLUE SEA SYSTEMS 5511e, the two batteries are not connected in parallel unless the switch is moved to the EMERGENCY position. This is the same action as one would have with the more common OFF-1-BOTH-2 style of switch if the switch were moved to the BOTH position. The Evinrude E-TEC Auxiliary Battery Charging Kit can be used with either type switch, as far as I can tell.
jasongillies posted 11-22-2012 07:28 AM ET (US)     Profile for jasongillies  Send Email to jasongillies     
Hi Jim
I noticed something interesting. I have connected two identical digital volt gauge to the batteries.

When I turn the switch off the house battery gauge lingers with displays for about 1second

The circuit to the motor the display is snuffed out immediately. This I think shows the regulator side of the motor can still draw some current if left connected


jimh posted 10-04-2013 09:55 AM ET (US)     Profile for jimh  Send Email to jimh     
Via some email correspondence with Evinrude, their engineers have expressed that it will be OK to connect the auxiliary charging lead for the second battery so that when the primary battery switch is in the OFF position the auxiliary charging leads are disconnected, that is, the leads from the charging kit would be wired to the circuit downstream of the primary battery switch, but they do warn that it is not at all recommended that the E-TEC be operated with the auxiliary charging kit output not connected to its battery. That would not be a normal situation, so I see no reason not to modify the circuit (I show above) so that the auxiliary battery charging output is wired downstream of the primary switch. In this way, when the primary switch is in the OFF position, there will not be anything connected to the batteries except the 120-VAC charger leads. I will probably undertake this change when I do some general updating to the primary power distribution on the boat next Spring.

[UPDATE 2017: I never got around to changing the wiring of the Auxiliary Charging Kit output to connect to the LOAD side of the battery switch instead of to the battery terminal. While it is certainly a workable arrangement, I just seem to have not found the time to accomplish it--jimh]

jasongillies posted 10-28-2013 05:44 PM ET (US)     Profile for jasongillies  Send Email to jasongillies     
Hi Jim. I read what you got back from engineers as confirmation to have both circuits disconnected with OFF. I would suspect turning switch to OFF with motor going could harm more than just the second charging circuit; it could spike any part of motor.

I think BRP should update the installation diagram for the Blue Sea switch as it is quite different to the normal (1,2, both) switch. The installation guide is depicted that 1 position is for normal use and with the aux cable can charge battery 2 with switch in position 1.

jimh posted 10-29-2013 09:08 AM ET (US)     Profile for jimh  Send Email to jimh     
ASIDE: This has nothing to do with the E-TEC Auxiliary Battery Charging Kit, but let me comment as follows

It is never a good idea to disconnect the battery from an alternator that is trying to charge that battery. In any alternator there is electrical energy stored in the field of the coils. When the circuit between the alternator and the battery is broken and a large current flow has been interrupted, the energy in the alternator's field is dumped out, creating a large voltage spike. Normally when the battery is connected, the low impedance of the battery across the circuit would absorb this spike and prevent it from reach a high voltage. With the battery disconnected, energy in the fields is able to create a large voltage spike. This sort of situation occurs in all alternators. It is the reason that it is never a good idea to break the circuit between an alternator and its battery when the engine is running and the alternator was pushing a lot of current into the battery. This is why primary power distribution switches have make-before-break contacts--so there is always a battery on the circuit when switching between them. In this regard, there is nothing unique about the E-TEC's alternator having a strong preference for not seeing its battery disconnected while the engine is running and the alternator is generating current into the battery.

jimh posted 12-12-2013 10:30 AM ET (US)     Profile for jimh  Send Email to jimh     
I was thinking about my boat sitting in the warehouse all winter. The wiring (as I show above) has the batteries connected to the 120-VAC charger. At one time there was some 120-VAC available in the warehouse, and I used to visit periodically, run an extension cord (a long one) over to the boat, and plug in the charger. I'd let the charger operate for 30-minutes while I had a coffee. In this way I figured I could keep the battery charge high and compensate for any lost leakage current resulting from the connection of the chargers when they were powered off. In theory the leakage current into the charger from the battery ought to be extremely low, but it always worried me.

I just had an epiphany about this problem. The solution is to pull the fuses in the battery charger leads. For example, in my diagram above, removing fuses F2, F3, and F4 will remove the chargers from the batteries. If this is done, the batteries will be completely isolated from any loads, as long as the sump pump load switch is set to OFF.

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