Charging system

[rochepoint]

I am thinking it is time to upgrade the factory charging system on our single 6.3544M Perkins. I was wondering what others have done or would recommend doing since this is an area that I have limited knowledge. Batteries are one D8 for starting and four golf cart batteries for house use, all are wet cells.

 

[FF]

Many folks will replace the 8D with a pair of group 31's , to save the back braking work of the 8D.

And remember 8D is a SIZE as are all the batt designations.Not a type , like deep cycle or starting .

IF you get enough amps from the setup , why change?

If you nrrd a bit more and have hight above the batts , the deep cycle gold carts can be replaced with taller "L16" sttyle batts.

Look on the Trojan site for dimensions.

Second question is how long they take to recharge , noisemaker , power hose or boats alt will all have different recharge times.

AS an anchor cruiser my favorite is a noisemaker with a 135A truck alt belted on and a 3 stage V regulator.

For BIG banks the 300A 24V bus alts are very fast and long lived.

 

[Tom.B]

Mike,
This is going to be my winter project too. I have the EXACT same rig as you (for the exception of a Group 27 as a starter) and plan on sticking with Sam's Club (Energizer) golf cart batteries. They are cheap and have 110 Ahrs each. Plenty for marina rats like ourselves but enough for a few nights out. However, I am thinking of going up to six of them if I can fit that many in the space provided. I'll be doing my usual and opening a long storied thread for silly questions and advice when the time comes. I hope to have either an Iota or Charles charger (inverter is yet undetermined). Currently the alternator only charges the starter bank and I plan on changing that too. Get Nigel Calder's book. It's a great way to get in on the ground floor and understand what is going so you can decide for sure what your needs are going to be and how to pick the right stuff.

 

[Tom.B]

Oh... BTW... I am moving this to the Electronics Forum.

 

[bshanafelt]

My first attempt to increase capability on my boat when I first got her was to add more batteries. I had 2ea 8d's in the shop, so thought I would just add them to the existing house bank of 1ea. 8d, for a total of 3.

I was hoping the alternator that came with the boat, a 60A small frame with internal regulation, would manage.

Of course, I shortly ran the house bank down to flat, as that setup would never be able to charge properly.

I then upgraded the alternator to a 130A small frame with external regulation. I also separated the start battery from the house bank with a diode type isolator. This worked quite well and would pretty much keep everything charged up. I did not like how hot the small frame alternator would get when it was putting out more than 90A, but I used this setup for a couple of years.

Then the isolator fried itself. I found out that Echo charging was a more prudent way to deal with the start battery scenario, so I tossed the isolator and put one of these on - it has worked flawlessly since installation.

Next upgrade was to fit a large frame alternator. I found a 200A unit, mounted it and upgraded all wiring sized to carry the higher current. I also installed a battery monitor (Link) to follow charging and usage. This was an excellent arrangement, as the alternator never runs hot, and I am now not just guessing at state of charge of the bank.

A couple years later it was time to upgrade the battery bank itself. I was tiring of wet cells and wanted to be rid of battery boxes and get out of the 8d batteries as they are heavy.

I found some AGM's in 6v size (60lbs ea). and fitted these for the house bank and a similar grp 31 AGM for the start battery. I had to tweak the charging profile on the regulators as well as the shore charger to match, which was fairly easy. I also fitted temp. probes to the battery bank and alternator.


Now I have a very robust system that gives me the option to remain at anchor for up to 5 days without needing to initiate a recharge cycle - this without drawing down the bank to less than 60%. After 2 days the bank is at 85% or so.

My boat is 12v, I use a small 500w inverter for misc 120v needs as necessary, and typical 24hr usage is around 125 amps.


I have a diagram of the system that I can email if anyone is interested.

 

[Tom.B]

I'm sure we are ALL interested! Good advice Shan.

 

[FF]

I shortly ran the house bank down to flat

Once a START style batt is "flat" it needs to be replaced.

Very high quality deep cycles can survive ONCE to flat if you dont keep them that way for over a day.

A SOC meter with alarm is worthwhile on any cruiser,

 

[koliver]

Mike
You didn't say what your "factory charging system" consists of. If you have a Perkins 55 amp alternator with an internal regulator, that is the first place a change is needed. If you have a "Constavolt" Charger, that is the second place. If either of those has been upgraded already, please say so, as that will influence any advice you get.

Third, or maybe first, what are your loads? Do you have a fridge? Of course you do. Is it a Norcold AC/DC? If so, that is the first thing that should be changed, as all by itself, it will have the greatest impact on your charging needs.

I looked at Roche Point when I was boat shopping in 1994. It was very clean, shelter kept, but I can't recall the answers to any of the questions I have posed above.

Taking your post at its worst, I will assume you have:
1 - Norcold AC/DC,
2 - 55 amp, dumb alternator,
3 - Constavolt 20 to 40 amp dumb charger.

For your start load, you need at most a single 4D.

For House, 4 golf cart batteries will not be enough unless you change out the fridge for a DC only version (see "Freddy Freezer", at North Shore Refrigeration). If you keep the power hog fridge, go to at least 6 GCs.

For alternator charging, get a high output (at least 100 amps, up to 140) alternator and Most Important, a three stage external "smart" regulator. Balmar or Ample Power have excellent choices.

For the Charge from shore power, get at least a 100 Amp "smart" charger. If you get a Xantrex 2000 watt Inverter/Charger, or equivalent, your world will change.

Last, some sort of monitor system. Again, Balmar and Ample Power are both good. This is less necessary if you have a readout from your inverter/charger, as you will get much of the required information there.

 

[FlyWright]

Great advice, koliver. I'm in the process of completing the same changes except for the onboard smart charger which I already had. I always had a voltmeter, but the LinkPro battery monitor provides a much better picture of the battery condition. The shunt providing instantaneous current flow from the bank is providing me motivation to shift to more interior LED lighting.

My new 120A Balmar alternator and MC-614 regulator are sitting onboard in a box awaiting my next industrious urge, but some of my other boat hobbies are getting in the way.