geem
Well-known member
I don't disagree but it's good to think outside the box occasionally
I don't like to follow the sheep
Solar panels, alternator; charging separate banks
- Thread starter sailoppopotamus
- Start date
I don't like to follow the sheep
Baggywrinkle
Well-known member
I don't disagree but it's good to think outside the box occasionally
.... and it's great that there are people who "think outside the box" - after all some peoples sole purpose in life is to act as an example to the rest of us
.... we all need that one wildebeest that tests the river for crocodiles 
I'm glad the OP is nearer to a solution.
Interesting to read the links, thanks @sailoppopotamus. Obviously, this all changes with a huge house bank and a high-output alternator, but you don't have either of these, or lithium. Good luck with whatever you decide.
The only further point - I think you will find that the Cyrix does isolate the battery banks effectively.
With no charge source present the batteries are not capable on their own of raising the voltage above the connect threshold - so they stay isolated no matter what loads are on each bank. Most boats pull up the anchor with the engine running, so having the alternator and the starter battery feeding the windlass means the house bank isn't needed. It can still be engaged though with the start button, and hopefully the electronics won't see a voltage drop that causes problems. It will probably be fine as all commercial solutions for boats and cars are specified to survive a typical engine start (graph posted earlier) so it's only either older stuff, home-made electronics or cheap consumer electronics that are vulnerable to an under-voltage reset.
The other scenario is ....
With a charge source present, and the banks connected, the power for the loads is not coming from the batteries if the charging source can hold the voltage above 12,8V. Large loads cause a voltage drop, but if the load is enough to pull both banks, and the charging source below the disconnect threshold, then there will be a disconnect. It is arguable if this is wanted or not, but again you can parallel it all up again with the start button in an emergency.
Basically, in the absence of a charge source, the banks will remain isolated, and there are thousands of these things fitted - they work quite well for your scenario IMO.
@Buck Turgidson did say his remained engaged during engine start while charging from solar, but he does have a house battery capable of 1300A and a relatively small engine which needs maybe 90A to start so it would seem that the house battery, the charge source, and the AGM starter battery are capable of holding the voltage above the disconnect threshold for the duration of an engine start.
Buck Turgidson
Well-known member
Yes that's what I think happens but the other option is the relay sticking so I'm going to do some more investigation next week..... and it's great that there are people who "think outside the box" - after all some peoples sole purpose in life is to act as an example to the rest of us
I'm glad the OP is nearer to a solution.
Interesting to read the links, thanks @sailoppopotamus. Obviously, this all changes with a huge house bank and a high-output alternator, but you don't have either of these, or lithium. Good luck with whatever you decide.
The only further point - I think you will find that the Cyrix does isolate the battery banks effectively.
With no charge source present the batteries are not capable on their own of raising the voltage above the connect threshold - so they stay isolated no matter what loads are on each bank. Most boats pull up the anchor with the engine running, so having the alternator and the starter battery feeding the windlass means the house bank isn't needed. It can still be engaged though with the start button, and hopefully the electronics won't see a voltage drop that causes problems. It will probably be fine as all commercial solutions for boats and cars are specified to survive a typical engine start (graph posted earlier) so it's only either older stuff, home-made electronics or cheap consumer electronics that are vulnerable to an under-voltage reset.
The other scenario is ....
With a charge source present, and the banks connected, the power for the loads is not coming from the batteries if the charging source can hold the voltage above 12,8V. Large loads cause a voltage drop, but if the load is enough to pull both banks, and the charging source below the disconnect threshold, then there will be a disconnect. It is arguable if this is wanted or not, but again you can parallel it all up again with the start button in an emergency.
Basically, in the absence of a charge source, the banks will remain isolated, and there are thousands of these things fitted - they work quite well for your scenario IMO.
@Buck Turgidson did say his remained engaged during engine start while charging from solar, but he does have a house battery capable of 1300A and a relatively small engine which needs maybe 90A to start so it would seem that the house battery, the charge source, and the AGM starter battery are capable of holding the voltage above the disconnect threshold for the duration of an engine start.
Baggywrinkle
Well-known member
You may well find that the voltage is dropping enough to start a disconnect timer, but the engine starts before the timer runs out so never disconnects - and as soon as the alternator starts going then it will remain connected.
It only disconnects immediately if the voltage is pulled below 11V .. it might well spike below 12V but not below 11V, and then recover enough to enter the 10s timer (between 12 and 12,2V) or maybe even the 30s timer - by which time the engine has started.
sailoppopotamus
Active member
In this respect the Blue Seas ACR seems like a better design, as it can be wired to the ignition key to isolate the two batteries. But I have to buy it over the internet and I couldn't wait that long.
I went shopping today and got myself a shiny new 80Ah AGM battery to replace my starter battery, the Cyrix, and a BlueSolar 75/15 MPPT controller. I'll wire everything up at the first opportunity and report back. I'm probably keeping the windlass and alternator on the start battery, and solar on the domestic supply. There's an argument to having all charging sources connected to the largest battery, but I'm not sure if that is still recommended if the windlass is connected to the starter.
Thanks to everyone who contributed to this thread, I have learned many things thanks to you.
I went shopping today and got myself a shiny new 80Ah AGM battery to replace my starter battery, the Cyrix, and a BlueSolar 75/15 MPPT controller. I'll wire everything up at the first opportunity and report back. I'm probably keeping the windlass and alternator on the start battery, and solar on the domestic supply. There's an argument to having all charging sources connected to the largest battery, but I'm not sure if that is still recommended if the windlass is connected to the starter.
Thanks to everyone who contributed to this thread, I have learned many things thanks to you.
PaulRainbow
Well-known member
The BlueSea VSR is no better.
The Victron one will work just fine.
If you want to solve a problem that does not exist, fit a normally closed relay to the negative wire and wire the trigger coil to the "ignition" positive. When you turn the "ignition" on, the coil will open the relay, the relay will open and the VSR will instantly open.
geem
Well-known member
My windlass has been connected to the domestic battery bank for 10 years. It has recently been connected up to the starter battery as we now have a lithium domestic battery. Inrush current on large DC motors is considerable. The motor is 1700w and there is a risk of BMS damage due to the very high current.
For 10 years, the windlass lived happily on the domestic battery with no voltage spikes on the electronics. It made sense for us to configure this way as we often hoist the dinghy using the windlass. So we are back to running the windlass off the engine batteries. Fortunately, we are a 24v boat, so we have a pair of 100Ah start batteries in series. They have capacity for windlass work and their own dedicated 40w solar panel and Victron smart solar MPPT.
sailoppopotamus
Active member
An update on my situation: I installed the new starter battery, Victron Cyrix and Victron Smart Solar 75/15 MPPT controller during the week. Solar charges house battery, alternator charges starter battery, and I left the windlass on the starter.
The installation of the Cyrix was very simple. I went overboard with the cable -- I originally planned to use a 10mm^2 cable to connect the two batteries but perhaps foolishly I ended up using 25mm^2. Thick marine cable is far more expensive than I expected it to be and I couldn't find a reasonably priced MIDI fuse holder for it around Lavrion, which caused great frustration.
I am quite disappointed that the 120A Cyrix I went for does not include a LED indicator to let me know what it's doing. This is only included in the 230A model for some reason. If I had read the manual carefully before purchase I would've known that, but alas I only realized this after spending 15 minutes wondering why the LED isn't turning on. Not having a voltmeter wired to the starter battery I can only hope it's working as expected. On the other hand the 230A model is more than twice the price, so I'm not sure it's worth spending so much money just for the LED indicator.
The MPPT controller is amazing. I now find that the batteries are on float by 1pm, compared to around 3pm with the PWM controller I previously had. I originally entertained the idea of buying the non-Bluetooth-enabled BlueSolar controller, and I'm so glad that I didn't. The Victron app works pretty well, and the ability to monitor panel output and charging status from my phone is very useful and extremely entertaining.
As a by-the-way, I had considerable trouble crimping the thick cables. I have a cheap chinese hydraulic crimper (50 euro, 'Total' brand) and an assortment of crimp terminals bought from local stores. After several failed attempts, I found that to crimp the 25mm^2/M6 lug I needed to use the 16mm die, but the 25mm die was sized right for the 25mm^2/M8 lug. None of the crimp terminals were of the heat shrink type so I'm not sure what could be going on other than badly manufactured terminals.
Once again, thanks to the forum and to all who offered their help and opinion on the matter.
The installation of the Cyrix was very simple. I went overboard with the cable -- I originally planned to use a 10mm^2 cable to connect the two batteries but perhaps foolishly I ended up using 25mm^2. Thick marine cable is far more expensive than I expected it to be and I couldn't find a reasonably priced MIDI fuse holder for it around Lavrion, which caused great frustration.
I am quite disappointed that the 120A Cyrix I went for does not include a LED indicator to let me know what it's doing. This is only included in the 230A model for some reason. If I had read the manual carefully before purchase I would've known that, but alas I only realized this after spending 15 minutes wondering why the LED isn't turning on. Not having a voltmeter wired to the starter battery I can only hope it's working as expected. On the other hand the 230A model is more than twice the price, so I'm not sure it's worth spending so much money just for the LED indicator.
The MPPT controller is amazing. I now find that the batteries are on float by 1pm, compared to around 3pm with the PWM controller I previously had. I originally entertained the idea of buying the non-Bluetooth-enabled BlueSolar controller, and I'm so glad that I didn't. The Victron app works pretty well, and the ability to monitor panel output and charging status from my phone is very useful and extremely entertaining.
As a by-the-way, I had considerable trouble crimping the thick cables. I have a cheap chinese hydraulic crimper (50 euro, 'Total' brand) and an assortment of crimp terminals bought from local stores. After several failed attempts, I found that to crimp the 25mm^2/M6 lug I needed to use the 16mm die, but the 25mm die was sized right for the 25mm^2/M8 lug. None of the crimp terminals were of the heat shrink type so I'm not sure what could be going on other than badly manufactured terminals.
Once again, thanks to the forum and to all who offered their help and opinion on the matter.
PaulRainbow
Well-known member
Thanks for taking the time to post your feedback
geem
Well-known member
T
The Victron Bluetooth stuff is better than telly
Buck Turgidson
Well-known member
T
The Victron Bluetooth stuff is better than telly
Yep! One of these isn’t even mine but the default password is in the manual
geem
Well-known member
You need more Victron
sailoppopotamus
Active member
With @geem's installation I think I'd spend all day just looking at the graphs in the app rather than boring myself sailing
Just one more question to the forum:
I have 2 x Lucas LSLC150 batteries as my service bank, and a Varta F21 as the starter battery. I can't find a datasheet for the Varta, but the Lucas datasheet specifies a temperature compensation coefficient of -6mV/C during bulk and -4mV/C during float. The Victron controller has only one setting, whose default value is -16.2 mV (for the whole battery). The discrepancy is quite large so I presume Lucas quote their figures per cell, rather than per battery, which means that I should probably set the value in the controller to -5mV/C per cell (midpoint of bulk & float), i.e. -30mV/C. This seems quite far from the default setting so I thought I'd double check with the forum that this is correct.
Lucas also specify a bulk charging voltage of 14.6V-14.8V and a float of 13.6V-13.8V so I assume that I can't go far wrong if I set these to 14.7V and 13.7V respectively. The boat is in Greece so temps in the boat will be generally around 30-35 degrees in the summer and around 10-20 degrees during the winter.
Just one more question to the forum:
I have 2 x Lucas LSLC150 batteries as my service bank, and a Varta F21 as the starter battery. I can't find a datasheet for the Varta, but the Lucas datasheet specifies a temperature compensation coefficient of -6mV/C during bulk and -4mV/C during float. The Victron controller has only one setting, whose default value is -16.2 mV (for the whole battery). The discrepancy is quite large so I presume Lucas quote their figures per cell, rather than per battery, which means that I should probably set the value in the controller to -5mV/C per cell (midpoint of bulk & float), i.e. -30mV/C. This seems quite far from the default setting so I thought I'd double check with the forum that this is correct.
Lucas also specify a bulk charging voltage of 14.6V-14.8V and a float of 13.6V-13.8V so I assume that I can't go far wrong if I set these to 14.7V and 13.7V respectively. The boat is in Greece so temps in the boat will be generally around 30-35 degrees in the summer and around 10-20 degrees during the winter.
Buck Turgidson
Well-known member
geem
Well-known member
30mV is quite normal for lead acid.With @geem's installation I think I'd spend all day just looking at the graphs in the app rather than boring myself sailing
Just one more question to the forum:
I have 2 x Lucas LSLC150 batteries as my service bank, and a Varta F21 as the starter battery. I can't find a datasheet for the Varta, but the Lucas datasheet specifies a temperature compensation coefficient of -6mV/C during bulk and -4mV/C during float. The Victron controller has only one setting, whose default value is -16.2 mV (for the whole battery). The discrepancy is quite large so I presume Lucas quote their figures per cell, rather than per battery, which means that I should probably set the value in the controller to -5mV/C per cell (midpoint of bulk & float), i.e. -30mV/C. This seems quite far from the default setting so I thought I'd double check with the forum that this is correct.
Lucas also specify a bulk charging voltage of 14.6V-14.8V and a float of 13.6V-13.8V so I assume that I can't go far wrong if I set these to 14.7V and 13.7V respectively. The boat is in Greece so temps in the boat will be generally around 30-35 degrees in the summer and around 10-20 degrees during the winter.
Your charge voltages are perfect.
You can also use expert mode and set the absorbtion to adaptive. If you are leaving the boat unused it's handy as the absorbtion time will adapt such that you won't be boiling electrolyte unnecessarily. Ie, shorter absorbtion time to reflect a full battery
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sailoppopotamus
Active member
Thanks for the tip. I'll do just that, since the battery doesn't cycle at all when I'm in my home port (I turn off the fridge).
