BabaYaga
Well-known member
A dual sensing VSR like the one proposed will steal a quarter of an amp from the solar output (for the questionable benefit of keeping connected a starter battery that is likely already fully charged).
Should I swap Starter and Leisure battery connections to my VSR?
- Thread starter Argold57
- Start date
PaulRainbow
Well-known member
And likely to stay that way.
BabaYaga
Well-known member
People install MPPT controllers to squeeze out maximum yield from their solar installations. In that perspective, sacrificing a quarter of an amp more or less continuously in order to counter long term self discharge of the starter battery (if that's what you referring to) seems a high price to pay, certainly so for modest solar installations.
PaulRainbow
Well-known member
It isn't continuos, it's 220mA while closed. Pretty minimal with anything but a very small installation.
If it's "to counter long term discharge of the starter battery" it's insignificant, if it's "long term" the domestic batteries will also be fully charged.
If it's short term (because the engine battery needs to be charged) it's a small price to pay to be able to start the engine.
drawp
Member
I have what VicS recommends and it works a treat without any operator input. The alternator feeds directly to the main batteries. The smaller (70Ah) reserve/emergency battery is kept up to charge through the VSR and is available for starting the engine if required. That is the only time you need to switch between battery banks.
halcyon
Well-known member
One of thereasons behind the design of the VSR was to keep a clean power supply for the boats electronics, source of the problem was engine starting on the same battery.
Brian
William_H
Well-known member
Yes you could try connecting alternator direct to domestic large battery. This if heavily discharged would take quite some time to recharge to the point where VSR operates to connect engine battery for charge.
Is OP sure domestic batteries are good. I suppose if mains charging brought them up probably OK. But I think worth disconnecting so only on domestic is being charged by VSR. If that is ok try the others alone.
Now assuming domestic battery is good just very low in charge. It is just too much a grunt for the alternator to hold voltage high enough to keep VSR on. It may be possible to adjust voltage for the VSR. (I will assume not) As said you need a gutsier alternator though perhaps more revs would do it. Or you could try introducing some resistance into the wire from VSR to domestic battery. It would not need much resistance. Perhaps use the stout wire but make it 4 times as long. This would then charge very low domestic battery at a more gentle rate for the alternator to handle. Or brutalise with a switch to bypass VSR when needed to force domestic battery on to charge. (alternator might get hot) ol'will
Is OP sure domestic batteries are good. I suppose if mains charging brought them up probably OK. But I think worth disconnecting so only on domestic is being charged by VSR. If that is ok try the others alone.
Now assuming domestic battery is good just very low in charge. It is just too much a grunt for the alternator to hold voltage high enough to keep VSR on. It may be possible to adjust voltage for the VSR. (I will assume not) As said you need a gutsier alternator though perhaps more revs would do it. Or you could try introducing some resistance into the wire from VSR to domestic battery. It would not need much resistance. Perhaps use the stout wire but make it 4 times as long. This would then charge very low domestic battery at a more gentle rate for the alternator to handle. Or brutalise with a switch to bypass VSR when needed to force domestic battery on to charge. (alternator might get hot) ol'will
Argold57
New member
OP here:
This is not a common issue on my boat. It does not happen unless the battery is deeply discharged. At this time that is not often but we retire next year and will start cruising much further so it may occur more often.
When I next get the chance, I will assess my alternator and cabling. It sounds like the best solution is to upgrade to a bigger alternator.
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Argold57
New member
Solar is out of scope for this thread.
Pete7
Well-known member
Well, no its not actually. We had the same chatter when the solar was connected to the engine start battery. Solar moved to the house batteries and the problem went away.
Pete
dk
Well-known member
It doesn't matter which way round you connect a dual-sensing VSR, it will simply turn on when it senses its trigger threshold from either battery. Early models were single sensing, which would act differently if reversed and did 'prioritise' batteries.
PaulRainbow
Well-known member
In post #1 you said:
That implies that you plan to fit some solar, in which case, it makes sense to ensure that todays solution for the VSR problem will still be applicable if you do fit solar.
A decent VSR will work perfectly well with your current setup and also work with solar.
The Victron Argofet mentioned by VicS will split the alternator output, so no more VSR chatter. But, if you fit solar later it will not allow the solar to charge both battery banks, unless you fit a dual output controller, which might not be the best choice, depending on what solar panels you fit.
I still maintain that a good VSR will solve the chatter problem and only cost £42. This is my day job and i fit lots of Victron VSRs in a year, i have never, ever, had a customer complain of VSR chatter.
Argold57
New member
There are a number of other threads dealing with VSRs and solar. The considerations for that case, I think, are somewhat different from the title of this thread.
This reply will likely cause a flurry that will hijack this thread anyway, but I think I got the answer that it is not really a good idea to swap connections but instead look into the alternator size and the features of the VSR itself.
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PaulRainbow
Well-known member
I see a couple of people have suggested removing your 1-2-Both switch, but i can't see where you have said you have such a device, do you ?
Argold57
New member
I do have the battery select switch but I think it is best to keep it in place. One consideration is it is mechanical where the VSR is electromechanical. The switch can serve as a backup.
PaulRainbow
Well-known member
So, when you have the engine running, you have the switch set to the engine battery ?
The conventional way of wiring the 1-2-Both switche is to connect the alternator output to the common terminal of the switch. When you turn the switch to the engine battery, everything runs from the engine battery and the alternator charge goes to that battery, when you seledt the domestic bank everything runs from the domestic bank and the alternator charge goes to the domestic bank.
If that's all the case, all you have to do to stop the SR chatter is to select the domestic bank, job done. That said, the whole arrangement is a bit of a dogs dinner and has plenty of room for improvement, without spending a fortune.
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Argold57
New member
I
I see where you are going though. I need to check where the alternator attaches to the system... I may be able to connect the leisure battery to the starter and perhaps the issue will be resolved.
I simplified a bit. We actually have three switches in one block: "house" "start" and "emerg. parallel".
I see where you are going though. I need to check where the alternator attaches to the system... I may be able to connect the leisure battery to the starter and perhaps the issue will be resolved.
halcyon
Well-known member
If you are going to discharging to a low battery level more often in the future, you are going to reduce your battery life, perhaps dramatically.
Not discharging below 50% is the norm. around 12.0 volt, but depends a little on current draw.
So if you use your batteries correctly you probably will have no further problem, if you plan to run them flat often fit one of Paul's VSR's.
Brian
PaulRainbow
Well-known member
That's not simplified, that's a totally different system, with respect, try and accurately describe what you have, or it makes any advice meaningless/dangerous
In the system you describe, the alternator will almost certainly connect to the starter battery, most likely the B+ wire from the alternator will go to the battery cable connection on the starter. It would be technically possible to move this connection to the domestic batteries, which should stop the VSR chattering, but it's not something i'd recommend. It would be odd and, IMO, a bodge around the VSR problem.
To recap my thoughts, i would do one of the following:
1) Fit a Victron Cyrix (no connection here, just advising based pn lots of experience with VSRs). That's it, £42, job done. In the worse cases of domestic battery SOC it's possible that the relay will only stay closed for a few minutes, then open for a short time as the domestic batteries pull the voltage down. You'd still get some charge into the batteries and after a a few cycles the voltage would hold up. I say this is possible, although i've never actually witnessed it with the Cyrix.
2) Fit a Victron Argofet. A little more work as you have to disconnect the existing alternator B+ wire and run a new one the the Argofet input. then run two cables from the output terminals of the Argofet to the batteries or the battery terminals of the isolator switches, whichever is more convenient. Definitely no chatter here and minimal voltage drop. If you fitted solar at some point, the solar will not charge the engine battery via the Argofet.
Both devices need to be fused as appropriate. Sample schematics of both installations below:
Argold57
New member
The switches are shown and on the side are the VSR and a thermal circuit breaker.
The alternator is connected to the starter solenoid and I think the Start switch ties the starter battery to the solenoid. The Emerg. parallel switch has 2 inputs to the VSR so I assume it shunts across the relay.
One way to stop the clicking would be to go into emerg parallel mode but that would discharge the starter battery into the leisure battery so I don't want to do that.
