Ericson 38-200 electrical power mods.

[oceandreams89]

Hi again everyone,

In my last thread of a few moments ago, I was asking questions concerning the addition of refrigeration to my 1989 38-200. My next concern is related to my electrical power system and it's ability to maintain the frige system.

I currently have 2 group 27 batteries wired to a perko 1-2-all-off switch. I currently switch one off to run the house from only one battery to conserve starting power. This will not cut it with a big draw item like a frige system. (I worry about it even sailing with all my little toys running so I limit use of things like the radar etc unless needed.) Now comes the plan...

I think the best solution is to add a dedicated start battery and use the 2 group 27's as the house. This should provide sufficient power for the basic house loads.

Has anyone out there modified their systems like this, and if so what type of gear installation is required to maintain all 3 batteries. If my understanding is correct I would have to add a on/off switch for the start battery and some kind of combiner system so that they all charge from the alternator.

Thank you to all that can un-scramble my wire woes....

Todd

 

[Geoff Johnson]

That's the modification I made on my 32-3 a year ago. My boat came with two Group 24's under the quarter berth with no real way to expand. So I did the following. I installed a Balmar high output alternator and Balmar 612 external regulator (you can see a picture of the alternator installation here - if you have an M25 engine make sure you do the alternator mount modification, as described)

http://www.ericsonyachts.com/infoexchange/showthread.php?threadid=736&highlight=alternator

I then installed a dedicated Optima AGM starting battery on a shelf in the lazarette, which is connected by a manual switch (with a removable key) to the common positive post and a negative bus which I installed. I replaced the two Grp 24's with Lifeline AGMs and hooked them up to a Link 20 meter to check charging, etc. I opted to leave the existing battery switch (some recommend hard wiring house batteries together), but almost always run it in the "Both" position to use the two Lifelines as a single battery bank. I also chucked my WM battery combiner since I keep the house batteries paralleled.

So now, I start the engine from the house batteries and keep the Optima as an emergency starting battery. Sometimes I will parallel it when the engine is running, but basically it never needs recharging since it is not used and AGM's have a very low self discharge rate (e.g. they discharged 1/4 when left for 5 months over the winter). AGM's are also a better choice for the house batteries since they can be charged at 40% of their rated capacity (e.g. 34 amps/hr for a Group 24) as opposed to 25% for flooded and, therefore, take better advantage of the the Balmar. BTW, I bought the stuff from Jack Rabbit Marine in Stamford, which has very good prices and can offer expert advice since all they do is wire boats. Have a look at their web site. (I have no connection with the company).

 

[valentor]

Todd;

Four years ago I upgraded my electrical system on my 1978 E-34. It was quite an adventure. The original Ericson system was terrible.

The old system was two group 27 batteries with a Perko 1-2-Both switch. One battery was always reserved for starting, the other for house. The system requiried almost equal an hour of charging for each hour of battery use - and it was necessary to replace one of the batteries every two years or so.

Warning: I work in electronics, so I got a little carried away with this!

First you must determine average current draw. This is done by multiplying the amount of time each appliance will be used by it's current draw. I used a spreadsheet for this. Then you decided how often you are willing to recharge your batteries. This leads you to the amount of Amp-Hours you must provide, but there are inefficiencies which must be accomodated before you size your battery banks. The biggest factor is that batteries should only be discharged to about 50% of their rated capacity - so you have to double what you thought you needed. Other inefficiencies include voltage drop over wires, current leakage in the charging system and appliances, and resistance in connections.

In my case, I needed two size 31 AGM batteries (210 Amp-Hours) to be able to sail the Chicago-Mac without running the engine. An additional size 24 battery was reserved for engine starting.

Next, you need to have enough alternator to provide the charging current at a high enough rate. I chose a Balmar 100 Amp alternator and a Balmar three-stage regulator so that I could charge the 50% discharged battery bank (105 Amps) in 2 hours. Another subtle little point is that battery capacity is inversely proportional to the currnet load it must provide. In other words, a 100 AH battery will provide 100 Amps at a current draw of 5 Amps per hour - but if the battery is loaded to provide 50 Amps per hour, it will not even last that hour.

So you also need a monitor that will keep track of not only how much cirrent you draw, but how fast you draw it. The Link-10 from Heart Interphase is a great device for this application.

In order to ensure that all that charging capacity was transferred tot he batteries - rather than dissipated as heat in small wires and old switches, I replaced all the corroded, undersized old copper wires with Ancor tinned #1 AWG wires. And just for a little extra safety, I isolated the batteries positive terminals with 135 Amp circuit breakers (as is required on commercial boats that must be inspected).

Finally, I followed the advice of the West Marine advisor and installed seperate switches for the house and engine banks. The thinking here is that there is no chance to accidentally run down the engine battery since it is not even connected to house loads. An emergency cross-over is included so that it is possible to start the engine from the house batteries in an emergency.

Since I keep Rogue on a mooring and do not have regular access to shore power, I installed a small 5 Watt solar charger just to top off the batteries during the week. For occasions that I do use a slip and can charge the batteries, I installed a small 10 Amp Xantrex true Charge unit.

The result - Even with four years on the system, I can still sail for three days without running the engine. We are not shy about using battery power. We run the computer all the time, watch DVD's during the off watch, run a microwave to cook meals for a crew of eight, an listen to a lot of CD's. Also my battery banks test at full (new) capacity. I don't expect to have to buy batteries for another 15 years.

If you want more information, feel free to email me directly.

Regards;

Steve

 

[rssailor]

Battery setup

Definetly go with an externally driven alternator for charging your batteries. Any P type alternator will work with a Balmar max charge MC 612H unit. This is the best regulator for charging any type of battery aboard a boat. Next thing you want to get is a digital duo charge also by balmar. This charges the engine start battery independantly from the house. Three wires are needed for its hookup. Using your existing group 27 batts would be ok, but really not enough juice for you needs most likely. Figure out what your power needs are and size your battery bank accordingly. Good luck and make sure you use good marine grade battery cable and heat shrink on all lugs. Ryan

 

[oceandreams89]

Hi everyone,

Thank you for all of your input to this project. I elected to keep it simple by doing the following:

I installed a group 24 deep cycle battery in the middle compartment under the starboard settee. I had to build a shelf on top of the grid structure for support. I connected this battery to the "2" side of my Perko battery switch, and wired the two house batteries in parallel to the "1" side of the switch. Now both group 27's are the house batteries with an emergency starter battery on "2". In the all position I can use all the power if needed and charge all 3 banks. So far it works great. Hopefully I will never need the start battery if I manage the power from the house side correctly. I eventually will upgrade the alternator and regulator to a Balmar setup but I will give the factory 50A unit a shot for a while.

Thanks again to everyone for their ideas and input.

Todd
s/v "Ocean Dreams" / Mystic, CT

 

[Geoff Johnson]

If you install an ammeter/volt meter (Heart) like I did, I think you will find that the max voltage of the OEM alternator/regulator is about 13.6 volts which will result in persistently undercharged batteries. The 3 stage external regulator (like the Balmar 612) will bulk charge at the appropriate voltage (depending on chemistry) or around 14.5 volts. Its float charge drops to about 13.5 volts.

As for trickle charging with a solar charger (valentor), I have read that trickle charging is a good way to kill an AGM battery and therefore avoid it, even though I am on a mooring.

Finally, I think the Duo Charge is unnecessary if all the batteries are the same chemistry. All the Duo Charge does is to allow you to apply two different charging profiles (e.g. charge flooded and AGM batteries simultaneously).

 

[rssailor]

Digital Duo charge

Geoff,

You are right the duo charge will take current (up to 30Amps) from the house to charge the engine start battery even if you have two different battery chemisties. A float charge of less than an amp at the proper voltage will not hurt an agm battery. Duo charge units are an excellant option for charging a second battery or the engine start battery. This avoids having to install a combiner or even worse an isolator. Go to Balmar.net and read about the duo charge before you bash it next time. Ryan owner of Ryan's Marine in Alameda CA

 

[Geoff Johnson]

I'm not bashing the Duo Charge. I think it is an excellent product, but it is an expensive solution ($200) if all you want to do is keep the starting battery charged. If the starting battery is of the same chemistry as the house batteries, all you need to do is to occasionally manaully parallel it when the engine is running. If your starting battery is of a different chemistry, however, then the $200 would be well spent since the battery will require a different charging profile.

 

[Loren Beach]

Duo Charge note

A bit of trivia on the "Digital Duo Charge" from Balmar, I just priced it at a dealer in Seattle. At Boat Electric it retails for $168.72. Perhaps this represents a normal "street price" since this company is not a discounter, per se.

Once I get our reefer system installed, I may be upgrading the charging system and also adding one of these. I have an AGM starting/reserve battery hidden under the aft berth and a house bank consisting of a pair of flooded Trojan T-145's.

BTW, Statpower has announced that they are soon bringing out an upgraded shorepower charger that will have separate output curves for several different battery technologies. Their press release stated initially that it would happen this spring, but now-- maybe later this year....

Best,
Loren in PDX

 

[Geoff Johnson]

Loren,

Can you hook your existing battery charger up to the Duo Charge so that you don't have to get the new Statpower or is it compatible only with an alternator?

 

[Loren Beach]

Charge source?

The Balmar schematic shows *only* an alternator hookup.
I guess you would have to check with Balmar, if their on-line info is not informative...
<http://www.balmar.net/duochargeinfo.htm>

I would guess that the device is looking for unregulated alternator output, and not the staged output from a shorepower charger....

That's my SWAG, anyway.


Best,
Loren

 

[rssailor]

Digital Duo charge

No problem the Duo charge will transfer juice between whatever batteries it is hooked up to as long as the source battery which is usually the house bank, it at or above thirteen volts. Basically you can hook up your charger to the house and the duo charge will charge up the other battery and keep it charged. When you are ready to go out unplug from shore power and fire up the engine. When the voltage on the house goes to thirteen volts or above duo charge comes on and charges the engine battery. System works well and I have installed several of these setups on my customers' boats. Good luck keep the posts coming. Ryan

 

[rssailor]

More duo charge info

the duo charge does not care whether the house battery is being charged by the alternator or the shore battery charger. It only cares the the source battery (usually the house bank) is staying above thirteen volts. Once source battery voltage drops below thirteen volts, the duo charge shuts off. It is a great unit allows for excellant charging of the engine battery. Ryan