Jump Starters

6 posts / 0 new
Last post
Stray1235
Offline
Joined: 2/21/18
Posts: 14
Jump Starters

Hi everyone,

On my C36 MK II (1999) I have a house bank comprised of two 4d lead-acid 12v batteries in parallel.  I do not have a separate starter battery.  There’s 360 watts of solar controlled with an MPPT controller and I have a Xantrex battery monitor keeping watch over all.  I use my two 4d batteries for engine starting and for all house loads—leaving the selector switch on BOTH always. 

Of course, even though it has never happened, I’m always concerned that I’ll run out of juice to start my diesel.  I sail in Lake Huron and each summer I spend a month cruising around in Canadian waters.  Sometimes I’ll even spend a week anchored at the same spot, but with all LEDs and careful attention to the battery monitor I’ve never gotten into trouble...

Nevertheless, for years I’ve considered putting in a separate starter battery and I’m aware of how that can all be configured, but given that I’ve never been dead in the water and that I love keeping things simple, I’ve another idea that I’d like to ask the forum about for your two cents. 

What I’d like to do is simply reconfigure my 1-2-Both switch so that one of those selections goes to a set of “Remote Battery Jumper Terminals” --you know--the kind Frankenstein has on the sides of his neck.  They would be installed near the battery switch and then, in the unlikely event that I run out of juice from my 4ds, I would simply clamp on to those posts with the alligator clamps from my 12-Volt Portable Lithium Jump Starter that I bought for 100 bucks.  I presently have the Weego version of these devices and according to the specs, it can jump start a 35hp diesel without even blinking. 

Am I missing something here?  Am I gonna bust my diodes, or fry my regulator, trash my 4ds, or is this simply not going to work for some reason?

Any thoughts out there?   Bueller...Bueller....
 

Sojourn's picture
Sojourn
Offline
Joined: 7/14/08
Posts: 165

Hi John, 

I'm guessing each of your batteries has a rating of about 200 amp-hrs.  There are two fundamental choices, continue with both batteries on selector switch #1 (wired in parallel) and add a staring battery on selector switch #2.  A clean and simple way to do that.  The other good choice is more complicated but good if you're cruising for the some on the Lakes, as I do.  That would require a Starting battery and a second selector switch.  The starting battery would be on #1 and the output of other selector switch goes to #2.  On "both" all three batteries would be available.  With you have all or any batteries available.

A couple of points: 

  • You should not use a battery below 50% of capacity, except, in an emergency.  
  • If you're away from shore power for several days at anchor, Switching between battery #1 and battery #2 is easier on the Solar panels.  You're chances of having a full battery in reserve is higher, particularly on cloudy or rainy days.
  • A size 27 or 31 should be adequate to start the engine and easy to keep charged once the engine is on, as it only needs a short burst of power.

I have the the second set-up 3 battery banks: #1, #2, and a starting battery.  My boat has 170 amp capacity solar panels.  My battery banks each contain two series 31 - 125 amp-hr AGM batteries, the starting battery is a series 27 AGM starting battery. I find I only start my engine, If I'm actually going some where, I like the quite.  

By the way, see you're not a member of the Great Lakes Cruising Club.  You should look into it.  Here's the link:  The Great Lakes Cruising Club (glcclub.com)

Best regards,

Lou
 

Lou Bruska
Sojourn
1985 C-36 Mk-I TR #495
Eldean Shipyard
Lake Macatawa (Holland, MI) Lake Michigan
Rallyback@comcast.net

Haro's picture
Haro
Offline
Joined: 11/7/14
Posts: 404

On my c36, the 2 4Ds are parallel at the 1-2-all switch on lug number 1 and a starter battery is installed in the cockpit lazarette as battery number 2 with its own switch located in the lazarette. 
The order of usage is to place the battery switch to All, which parallels all 3 batteries, or bank 1 and 2, then start the engine. The alternator will charge all 3 batteries.
when sailing, after the engine is off, place the switch on 1 so the starter battery is disconnected.
Since the 110VAC charger is set to charge only one type of battery, then all batteries must be alike. Mine are all wet cell. 
When at the slip and your solar panels are charging then place the switch on All, but not when you are sailing.
I have a 100 watt solar panel and my batteries are always charged.
By the way, if your batteries become fully charged and you turn on the engine, you might find that the tachometer does not work. It is because the alternator does not need to put out any current.  To test this turn on your freezer compressor and the tachometer will start to work again.
Visit the website on my signature for more content on solar panel charging.

Brazen
Offline
Joined: 4/6/23
Posts: 12

As pointed out above a good choice would be "continue with both batteries on selector switch #1 (wired in parallel) and add a starting battery on selector switch #2".
All the charging sources ( solar/AC/alternator) can be wired to a bus bar connected to the existing house bank terminal on the 1/2/OFF/BOTH switch. Then use an ACR between the house bank and new starting battery to keep both charged. There is plenty of room for a small starting battery  and ACR in the seatbase with the battery switches, that makes wiring simple.

 

Denis
Brazen Article #1925
2001 Catalina 36 MKII

Sojourn's picture
Sojourn
Offline
Joined: 7/14/08
Posts: 165

A brief correction to my post.  I have 170 watt (not amp) capacity for the solar panels.  Effectively on a clear sunny day, 8+ amps are available to charge the batteries.  Your 360 watt capacity doubles my output or about 17 watts.  More than enough to keep them charged.

Lou

Lou Bruska
Sojourn
1985 C-36 Mk-I TR #495
Eldean Shipyard
Lake Macatawa (Holland, MI) Lake Michigan
Rallyback@comcast.net

Brazen
Offline
Joined: 4/6/23
Posts: 12

Mainesail wrote an interesting article about batteries and the 1/2/BOTH/OFF switch. His suggestion is instead of considering a HOUSE bank and STARTER battery look at them as MAIN BATTERY and RESERVE.
Everything including the engine start is run off the MAIN bank, the RESERVE is there in the event of a main battery failure.
You could parallel the MAIN and RESERVE batteries but there isn't a real need to switch anything, just run off the #1 side all the time.
With all charging sources run to the MAIN battery the Blue Sea ACR manages and keeps both batteries healthy. 

Denis
Brazen Article #1925
2001 Catalina 36 MKII

Log in or register to post comments