Beefed up battery charging

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Beefed up battery charging

Postby mike cunningham » Tue Jul 28, 2015 9:35 pm

I participated in a 5 day offshore race recently and found myself charging about 3 hrs per day. My 24/7 load was around 3 to 4 amps: plotter, AIS, AP, vhf, instruments.

I have a 50 amp balmar alternator and this worked ffine albiet slowly. I wonder if there is an approach to placing a more powerful alternator on line? Two advantages, quicker charging and a bit more load on the engine. I have read its not ideal tovrun the engine with minimal load

Any ideas/comments appreciated.
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Re: Beefed up battery charging

Postby rvivian » Thu Jul 30, 2015 12:03 am

Try adding solar panels or a wind generator.
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Re: Beefed up battery charging

Postby mike cunningham » Thu Jul 30, 2015 11:17 am

I am considering exactly that but when I put a 24/7 power budget together I am looking at about 84 AH consumption per day with the AP. I think I am going to have to have a very large and expensive and awkward Wind/Solar system to reliably replace that much power with no engine charging. Furthermore the system would not be appropriate for my typical cruising activity. I am planning on a long singlehanded race - two weeks or more - and I though some type of supplemental engine driven charger might be a better investment for me.

My thought was some sort of switchable charger which would provide normal charging when motoring but was capable of being switched to significantly higher output (and engine loading) when charging only.
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Re: Beefed up battery charging

Postby jdpandlp » Thu Jul 30, 2015 3:50 pm

I put a 100 amp Balmar dual charge alternator with their Blue Max charge regulator on White Wings 9 years ago when I changed the batteries over to two 8D AGM and a seperate starter battery. Engine is a Yanmar 4JHE. I also have a 4.3 KW NorPro generator which is primarily used to run the air conditioning during the summer in the Chesapeake and is not used normally to charge batteries.

Some items of interest on the change.
1. I installed the batteries first and nearly melted the standard 50 amp alternator because the agm's will accept much more amperage than the 50 Amp will put out. Take care in matching charging source to the battery bank size and type.
2. The 100 amp alternator is the upper limit of what a 1/2 inch alternator belt will drive. I burnt up several belts before I got serious about belt quality and tension. Also, the difference between the shape of a metric belt and a standard american belt is not a problem until you get to the very edge of the working load limits. The metric belts have a much greater service life in my application. I change the belt every time I change the oil now and have not had a problem in years. Knowing what I know now I would include an upgrade to dual belts or one of the newer serpentine belt/pulley replacements.
3. I installed 2 90 watt solar panels.
4. Switched to Flat screen TV which provides a huge saving in amp's used at anchor. Also have changed most of the lighting to LED now that they have become available in the 2700K light range, minimal amps and much cooler.

With my current components the time motoring in the normal course of a passage such as in and out of the achorages, motor sailing in low wind, ect, supplies the bulk of the amps I need. The solar panels supply at anchor power and battery charging to top off and supply a float charge.

This system is pretty straight forward and put together with off the shelve parts. It has taken care of my underway needs for several long trips as well as 7-10 day long outings in the chesapeake. Also it seems to be battery friendly as the original Lifeline 8D AGMS are still in good shape after 9 years.

Hope this helps some, Pete
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Re: Beefed up battery charging

Postby AlanK » Thu Jul 30, 2015 4:11 pm

On my F-33 I typically do local sailing/cruising but when I did a trip from Boston to Bermuda I installed a hamilton ferris wind towable water generator. This worked out very well and when I'm doing long distance passages I just stow it. Of course it doesn't help if one is becalmed. Just a possibility if it fits your usage model. If you go with it and want some tips on using it let me know.
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Re: Beefed up battery charging

Postby mike cunningham » Fri Jul 31, 2015 11:47 am

jdpandip,

The rig you describe sounds interesting.

I upgraded my electrical 8 years ago (my how time flies) and I replaced my lead acid 120 AH bank with 3 110AH Lifeline AGMs at that at time. These lifelines are going strong to this day!! But I think charge time is increasing somewhat which may be part of the problem.

I did size my 60 amp Balmar charger to Balmar's recommendations vis a vis bank capacity. I have an echo charger on one of the three batteries which is switch isolated to start only so house is limited to 220 AH unless emergency forces me to switch in the start batt which provides the addional 110AH to house. The switch also allows extra oomph from the house if the start battery has issues.

All that said, I like the idea of simply increasing the alternator capacity and upgrade belts to accommodate. I know the batteries will accept the additional current. I will need to check physical sizing to determine if I have the room. I note alternator cooling can also be an issue so I need to look into how to supplement airflow in the tight space below the steps on the F30.

BTW: Practical Sailor has a good article about AGM charging in the current issue. One thing I have worried about for awhile is the issue with partial recharge of the AGM bank. Practical Sailor calls this Partial State of Charge (PSOC ). In my case it takes forever to get a 100% charge when doing engine charging. A three to four hour session will get me to about 90% from 60% but it takes many more hours to get to 100%. The net result is I am almost always doing PSOC. The PS testing revealed Lifelines loose about 10% of their baseline capacity after 30 PSOC cycles. This may be a very strong argument of installing some supplemental panels, wind, towed generator and its not an issue I considered previously. The alternative would be to choose a more expensive Firefly AGM which PS found lost no capacity after 30 cycles.

Gee wiz, now we know why engineers have some much fun juggling all these variables!!
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Re: Beefed up battery charging

Postby rvivian » Fri Jul 31, 2015 11:02 pm

Mike -

I've got three 105 aH AGM house batteries and a fourth 105 aH AGM starting battery on my F-30 with the same switch and echo charger arrangement you posted a couple of years back. (Moved them under the port settee).

I have added the 70 amp Balmar alternator and smart external regulator recommended for our 2GM20 engines. I also installed a 150 watt 22V solar panel on the stern and a MPPT controller that mostly keeps up with the fridge and LED lighting loads -- even at Latitude 48 N.

You need a combination of charging options for your race, the fuel alone for running the engine to charge with a 100 amp charger will be problematical on the F-30 over a two week race.

I also think we think too much about the battery bank life for our usage. We should cycle our batteries as much as needed for our service without regarding the battery life too much. AGM batteries are expensive, but using them up is just one of the costs of doing business on the boat.
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