automatic charging relay

[DesertAlbin736]

If you need the capacity of a pair of Group 27 AGM's, may I suggest you look at a pair of AGM golf cart 6 volt batteries in series. You'll have a few more amp hours and no need to run paralleled batteries. The 6 volts in series should last at least 2X (or maybe even 3X) as long as a pair of paralleled 27's. I have a pair of flooded golf cart batteries in the engine room as my starting battery and a pair of AGM's (because they are located in the lazzarette which is technically part of the sleeping quarters on an A27.) which run the fridge and most other heavy loads. An ACR connects them all together when charging either from the 110 amp engine alternator, the 40 amp Shore power charger or the 320 watts of solar panels

I use a pair of 6V flooded golf cart batteries for my travel trailer. I wanted to get away from flooded wet cell batteries for the boat mostly due to the fact that I'm relocating my batteries to the starboard bench seat lazarette in the cockpit, where the opening is just large enough to drop the batteries in one by one, but would be difficult to check and refill battery water on the ones farther from the opening. The lazarette does have some ventilation, but not as much as the origninal location. I'm also installing a new ProNautic 1215P smart charger that has charging leads for 3 banks, so each battery gets its own wires & can proportion the charge to each. Ditto the 20 watt solar panel for float charging when in storage, which will have a new smart charge controller with leads to each individual battery. I have a switch in the + side lead coming from the solar panel, so I can switch it out of the circuit when not needed. Alternator is the standard Yanmar 55 Amp, for which I'm also installing an AGM compatible external voltage regulator.

Also upgrading the AC side with new Blue Sea Systems Main + 6 breaker panel to hard wire the charger to a dedicated circuit plus 2nd circuit for outlets (I only have three outlets and no other AC accessories, and no fridge, just a 5 day cooler). Also will be changing out the 1st outlet for a GFCI, and adding a galvanic isolator to the AC ground circuit. On the DC side the only electronics so far are the VHF radio, a fish finder, and my Garmin GPSmap76cx with cable to run off 12V. As far as the AGM house batteries getting unblanced between the two, that's just a chance I'll have to take. All three batteries are brand new, purchased from the same store at the same time. Besides which, I already bought the batteries, and a pair of 6V AGMs would be at least $136 more than what the pair of 27s cost me not counting shipping or sales tax, depending on whether bought local or online. I suppose I could hook up my old 3 way switch to allow manually isolating the + side of those two house bank batteries and take them out of parallel when on the AC charger?

This boat lives mostly on the trailer away from any AC sources, and only occasionally gets plugged into shore power at transient slips for a night or two at a time. Otherwise we anchor out as often as possible when cruising.

If there are any stray currents or galvanic action in the water at a marina, it won't be coming from me.

I'm sizing my battery cables for ampacity according to the formula CM= I x L x 10.75/E where CM is wire diameter in circular mills, I is current, L is length (both + & - combined), 10.75 = resistivity of copper, and E is allowable voltage drop @ 0.36. Figuring 300 amps and 15 ft cable length puts it at about 2/0 gauge wire size.

I just finished drawing up this schematic of the planned system today. I did not include temperature sensing leads in this drawing.

[djpeewee]

This looks good Desert. A couple of suggestions:

ABYC specifies minimum wire size of 16AWG.

Also, I think you will need somewhere around 10AWG wires from your battery charger to batteries depending on the length of the wires (red + black = total length).

[DesertAlbin736]

Also, I think you will need somewhere around 10AWG wires from your battery charger to batteries depending on the length of the wires (red + black = total length).

You're probably right about 10AWG. 15 amps max, no more than 20 foot total length counting all twists and turns. That is unless I can somehow locate the charger closer to the new battery location. Worst case would be all available 15 amps going to one battery, and there will be separate wire runs to each battery to charge proportionally, and of course each positive lead fused at the battery for that wire size.

I wish you could see what the DPO (Dreaded Previous Owner) used for wire. The main house circuit negative ground wire back to the engine block is RED wire !?!?!?! Stranded copper automotive wire, none of it is tinned boat cable, including the main battery cables. And of those only the positive cable from the start battery to the old 3 way switch had red insulation. All others including all positive cables have black insulation. And in fact the cable from the house bank to the 3 way switch is connected with a standard automotive type top post clamp. (see photo in an earlier post in this thread). Believe it or not, the DPO used regular trailer wire (4 wire bundle) for 12V from the old charger to the batteries, about 16 ft total + & - length. No shrink wrapping and no fuses at the terminals either.

The more I get into it the more I realize I paid that DPO way too much for this boat. But what is one to do? Not like there are a lot of Albin 25s around to choose from, and at the time we bought this one only 3 other examples were listed for sale, and those were thousands of miles away in British Columbia and Florida.

I'm using this "Sailboat Electrics Simplified" by Don Casey as my "bible".

By the way and a bit off the subject, how about that crazy weather back East? Right now at 11AM MST it's warmer in Boston than it is in Phoenix. There's snow and skiing 2 hours away from here in Flagstaff. I had to actually winterize the raw water system on the boat the other day since it dropped into the 20s overnight last week and may do so again next week. Guess I can't complain too much, up in the Pacific Northwest this has been the winter from hell.

But then we do have our sunsets. The photo below taken recently not far from our house.

For you guys in the Northeast and Mid Atlantic, the winter you're having this year is what is normal for us.

[djpeewee]

Given the parameters you listed (20' @ 15A) you are right at 10AWG. I wouldn't go any smaller in wire size even if you can get the runs shorter.

One other thing I noticed is that you have charging wires from the chargers (AC and solar) to each of the 3 batteries. Because you have the 2 house batteries permanently connected in parallel, the charging wires to them are in parallel and redundant. Only one charging wire per charger to one of the house batteries is needed in this configuration.

You are doing the right thing by replacing the non-compliant cable. The number one source of boat fires related to electrical wiring. Make sure you fuse everything as close to the batteries as possible. Don't be afraid to fuse the start battery as well. In the olden days this was frowned upon, so you may see differing opinions. With the redesign/rewire of Trygon I added fuse protection to each of the 3 batteries including the start battery. Never have had blown fuses or other problems. Carry spare fuses. FWIW, I have 23' of 2/0 red boat cable left over from my rewire. I'd be happy to get rid of it if you are interested. PM me.

I like your photo of the sunset. It brings back fond memories. I see that your boating is mostly on Lake Pleasant. In the '90s I worked on the New Waddell dam which created the lake. Quite controversial at the time. I installed all the automated hydro power controls. I remember what it was like before the lake was there. Lot of beautiful cactus (cacti?).

Our winter hasn't been too bad here. More rain than normal though - just over 9" this month alone. Very unusual.

[djpeewee]

Oh yes, of course... how could I forget a picture?

We might not have the sunshine or the cactus, but we do have interesting sights between periods of rain. I took this on my way back from lunch today:

Vanguard-Pioneer.JPG

This is the Dockwise Vanguard, the world's largest ship of its kind. Capable of carrying something like 240,000,000 pounds of cargo. Right now, it is the tallest man made structure in our little town. The cargo on its deck is the Polar Explorer, an oil rig. It spent the summer doing some controversial oil exploration in the Chukchi Sea in Alaska.

Yet I digress again.

[DesertAlbin736]

Related item: Wiring upgrade project, what's wrong with these pictures?

Photo 1: You are looking at the sum total of the existing 120 V AC shore power distribution system on our Albin 25. Old fashioned screw in fuse block (I replaced the fuse with a push button reset breaker). All the wires looked black until I wiped the crud off and could see which ones were actually black, white, or green. One simple screw post terminal for all green wire AC grounds back to the shore power inlet, but no connection across to the DC negative ground & hull bonding plate. Exposed buss bar for all white wire neutral terminations. Serves three 15 amp grounded outlets on single circuit, but only protection is the main 30A fuse/breaker. No shutoff toggles, breaker only on hot side, no reverse polarity indicator (therefore if reverse polarity existed one would not know & would have no breaker overload protection), no GFCI. Previous owners ran with this set up for 11 years and did nothing to upgrade it.

Photo 2: Entrance of the shore power connection on starboard side of wheel house. Nothing particularly wrong here, other than perhaps ancient wiring and no blade terminal ends. Is located above and to the left of Photo 1.

Photo 3, DC house circuit buss bars for various running lights, anchor light, cabin lights, bilge pump, GPS, VHF, depth sounder, etc. Located in head compartment behind access door. Individual fused switches on distribution panel at the helm station dash on other side of this bulkhead. Guess which ones are positive side & which are negative grounds? Hint: the larger red wire leading to the top row of buss bars and the right half of the bottom row are negative wires, left half of bottom bar are positive leads. All are regular automotive non-tinned stranded copper wire, none are marine grade. The blue wires are apparently old Swedish wiring code colors?

Photo 4: Will be installing this Blue Sea Systems AC + 2 position ELCI breaker panel, just received yesterday, plus a galvanic isolater which is on order and due for delivery next week. One circuit dedicated to new hard wired ProNautic battery charger, 2nd for outlets, and 3 blank positions for future add ons.

Happy New Year!!

[kaylakingsbury96]

Automatic chargers are doing well now a days

[Northern Spy]

Anybody have experience with the Yandina c100? Im looking for a caveman simple solution to charge my isolated starter and house battery banks. I have 2 12v group 31's in paralell as the house and a single for the start. Right now they are completly separate, I really do not want to install a switch to combine them. All I want to do is be able to charge the house from the alternator and the starter from the shore power charger automatically. Defender had the c100 on sale so I went out on a limb.