I have a chance to burn through some banked holidays so I am planning a month to do some overdue home and boat work. On the list is the battery charging for the boat. I currently have 2 x 100 watt flexible solar panels connected in parallel, connected to a a cheap PWM solar controller and a stock 60 amp Hitachi alternator on a Yanmar 3ym20 feeding 2 x 79 Ah agm house batteries. There is also a 79Ah agm starter battery but that is not hooked up to the solar. I just bought 2 x 130 watt flexible solar panels and I will replace my 100 watt Ebay specials with them and a Victron 20 amp MPPT solar controller. I plan on connecting the new panels in series. I'd love to keep my 100 watt panels but I'm not sure if I have enough room. I may reconsider. What I have now seems to keep up with our demands for 4 or 5 days anchored out but I'm not sure I'd get another day out if we have too many cloudy days and I am pushing the envelope. I swapped out all of our lights for LEDs so our biggest power demand is the icebox and my families affection for our stereo. Would there be any point in buying an aftermarket 80 amp alternator to swap for my 60 amp just to add some charging ability? I also thought about a battery to battery charger. Thanks for any input. This is season 5 for my agms.
Alternator Swap
- Thread starter Phil Mac
- Start date
Adding an aftermarket externally regulated alternator to your system will greatly improve your charging capacity. However, be forewarned, planning electrical upgrades is a trip down a deep and twisting rabbit hole. The first stop on your journey should be MarineHowTo.com. This site is one of, if not, the best source of reliable information on the internet. I am a frequent visitor.
The first step in this journey is to install a reliable and accurate monitoring system. Without a monitoring system there is no way to accurately know what's going on with the charging system and the battery's state of health. Balmar makes 2 monitors, the SmartGuage and the SG200 both are good products, having one of them is essential. That's half the monitoring system. The second half is a good ammeter that reads from a shunt at the battery bank. The Victron BM 700 fits the bill. The Victron can do more than simply monitor the current going in and out of the battery, it can also measure voltage, count amps going in and out, count watts, and give an indication of the State of Charge.
For me, the big issue with solar is partial shading by rigging, masts, and sails. When panels are wired in series if one part of one panel is shaded the total output drops rather significantly. Separate panels with separate MMPT controllers helps to mitigate this issue. If one panel is shaded or fails, the other panel continues to function. See the article below by Nigel Calder for some of the best and most recent info on solar.
It is not worth spending money on an aftermarket alternator unless it is externally regulated. See the articles on this on MaineSails MarineHowTo.com site.
This should get you started down the rabbit hole.
www.proboat.com
The first step in this journey is to install a reliable and accurate monitoring system. Without a monitoring system there is no way to accurately know what's going on with the charging system and the battery's state of health. Balmar makes 2 monitors, the SmartGuage and the SG200 both are good products, having one of them is essential. That's half the monitoring system. The second half is a good ammeter that reads from a shunt at the battery bank. The Victron BM 700 fits the bill. The Victron can do more than simply monitor the current going in and out of the battery, it can also measure voltage, count amps going in and out, count watts, and give an indication of the State of Charge.
For me, the big issue with solar is partial shading by rigging, masts, and sails. When panels are wired in series if one part of one panel is shaded the total output drops rather significantly. Separate panels with separate MMPT controllers helps to mitigate this issue. If one panel is shaded or fails, the other panel continues to function. See the article below by Nigel Calder for some of the best and most recent info on solar.
It is not worth spending money on an aftermarket alternator unless it is externally regulated. See the articles on this on MaineSails MarineHowTo.com site.
This should get you started down the rabbit hole.
Marine How To - DIY for Boaters - Marine How To
For DIY boaters in an attempt to try and keep the sport as affordable & safe as possible. How To articles for sailboats and powerboats.
marinehowto.com
Advances in Onboard Solar - Professional BoatBuilder Magazine
Advances in onboard marine solar technology improved efficiency and lowered the cost. But they also introduced more complexity.
www.proboat.com
Do you plan to ever upgrade your battery bank? I started with an almost identical setup with similar power requirements and went through a similar upgrade path. Eventually I found that my two 100AH AGM batteries just weren't enough so I took a chance on one of these:
The battery is awesome but I soon discovered that charging it was cooking my alternator. I had to disconnect the alternator from the house battery so it just charges the start battery now. I guess my point is that, if you plan on upgrading your battery then you'll need an alternator with a smart regulator so it doesn't just pump whatever current the battery asks for.
The battery is awesome but I soon discovered that charging it was cooking my alternator. I had to disconnect the alternator from the house battery so it just charges the start battery now. I guess my point is that, if you plan on upgrading your battery then you'll need an alternator with a smart regulator so it doesn't just pump whatever current the battery asks for.
The take home lesson here is that electrical systems are just that systems. If one part of the system is out of balance the effects are felt elsewhere in the system. In @PropellerHead situation, he increased storage and charge acceptance to a level that was out of balance with the charging source (alternator) with the result being a dead alternator.
This is the rabbit hole electrical system redesign leads to, ya can't just mess with one part without affecting other parts.
I'd like to add that it can still be done on a budget if you're willing to accept some limitations. I ended up with 300watts worth of solar panels (two in series) through one of these:
My power requirements being modest, I was able to route the input side of my power panel directly to the 12V output terminals of the charger (which can handle 40Amps). The remote control module (mounted in my panel) provides charge current, current to the panel, battery current and battery voltage. It's not really a complete 'state of health' because charge state of Lifepo is more complicated than just voltage but it was good enough for me.
I found that, with this setup, I had enough juice to power the boat through two or three days of heavy overcast with the alternator charging only the start battery. I spent a month off grid in the Bahamas without ever plugging into shore poer
My power requirements being modest, I was able to route the input side of my power panel directly to the 12V output terminals of the charger (which can handle 40Amps). The remote control module (mounted in my panel) provides charge current, current to the panel, battery current and battery voltage. It's not really a complete 'state of health' because charge state of Lifepo is more complicated than just voltage but it was good enough for me.
I found that, with this setup, I had enough juice to power the boat through two or three days of heavy overcast with the alternator charging only the start battery. I spent a month off grid in the Bahamas without ever plugging into shore poer
Thanks. That's a lot to think about. I did get a Victron battery monitor when I bought the solar controller but that was really to monitor battery temperature and state of charge. When I load tested my batteries at the end of the season they all still tested as good but I have a feeling after 5 years I'm getting close to the end of their life span and I may be looking to upgrade at some point. Thanks for the input. I really need to do an energy budget and see if I can find some more real estate for solar. I have power at my slip so the batteries are charged of the Xantrex charger regularly as well. I'm thinking that there may be no point in simply swapping my 60 amp for an 80 amp internally regulated alternator.
If you are not going to change to an externally regulated alternator, then you are correct the benefit will be minimal.
Adding a SmartGuage will be beneficial because you will know the state of charge for your batteries. That will keep you from discharging them too deeply which will prolong battery life.
The other thing to consider is changing from Group 27 AGMs to a single bank of 4 6v golf cart batteries. If you have room for them you'll get about 460 ah of battery capacity. Even changing to 2 6v GC batteries will give you more capacity for less money with batteries that are less sensitive to being at a partial state of charge.
I warned you this was a rabbit hole!
Thanks for the links. The Nigel Calder article just made me feel bad for not forking out the extra for the Sunpower panels but it was certainly a rich source of information.Adding an aftermarket externally regulated alternator to your system will greatly improve your charging capacity. However, be forewarned, planning electrical upgrades is a trip down a deep and twisting rabbit hole. The first stop on your journey should be MarineHowTo.com. This site is one of, if not, the best source of reliable information on the internet. I am a frequent visitor.
The first step in this journey is to install a reliable and accurate monitoring system. Without a monitoring system there is no way to accurately know what's going on with the charging system and the battery's state of health. Balmar makes 2 monitors, the SmartGuage and the SG200 both are good products, having one of them is essential. That's half the monitoring system. The second half is a good ammeter that reads from a shunt at the battery bank. The Victron BM 700 fits the bill. The Victron can do more than simply monitor the current going in and out of the battery, it can also measure voltage, count amps going in and out, count watts, and give an indication of the State of Charge.
For me, the big issue with solar is partial shading by rigging, masts, and sails. When panels are wired in series if one part of one panel is shaded the total output drops rather significantly. Separate panels with separate MMPT controllers helps to mitigate this issue. If one panel is shaded or fails, the other panel continues to function. See the article below by Nigel Calder for some of the best and most recent info on solar.
It is not worth spending money on an aftermarket alternator unless it is externally regulated. See the articles on this on MaineSails MarineHowTo.com site.
This should get you started down the rabbit hole.
Marine How To - DIY for Boaters - Marine How To
For DIY boaters in an attempt to try and keep the sport as affordable & safe as possible. How To articles for sailboats and powerboats.marinehowto.com
Advances in Onboard Solar - Professional BoatBuilder Magazine
Advances in onboard marine solar technology improved efficiency and lowered the cost. But they also introduced more complexity.
Wow. That's a serious battery. I have no doubt it would reduce my Hitachi alternator to a smoking ruin.
Once you price them, you may not feel all that guilty. The top of the line Solara panels are distributed by Coastal Climate Control.
Coastal Climate Control
Coastal Climate Control, marine refrigeration, air conditioning, flexible and walk-on solar panels, systems monitoring, and battery solutions, including lithium batteries