Installation of a VSR

Z

zambra

New Member
Joined
28 Oct 2012
Messages
6
Visit site
I'm hoping to take shameless advantage of forum expertise! Having read everything I can I'm still a bit confused regarding my reconfiguration of my boat's electrical system.
I am installing two 120 amp 12 volt batteries in my boat as the leisure bank and one 12 volt 60 amp battery as the cranking battery. I am linking the two with a VSR. The batteries will be charged from the alternator and from a multi stage battery charger of a suitable size when on shore power. I'd be very grateful if you could assist with two questions:

1. As the amperage of the leisure bank and the starter battery is different, it this likely to have an adverse effect on the starter battery when both leisure and cranking banks are linked through the VSR? I thought perhaps the cranking battery might be overcharged?

2. The boat is a beneteau 321 with individual switches for the battery, currently wired for master on, battery 1 and battery 2. Can I incorporate these switches into the VSR installation and are there any advantages to this or would it be better to remove them altogether?

Any help gratefully received!
 
You need to keep the switches, so that you can isolate the batteries when you leave the boat.

The engine battery won't get overcharged - batteries only take as much current as they can absorb. The battery ion your car is constantly connected to the alternator, and it doesn't get overcharged.
 
zambra said:
I'm hoping to take shameless advantage of forum expertise! Having read everything I can I'm still a bit confused regarding my reconfiguration of my boat's electrical system.
I am installing two 120 amp 12 volt batteries in my boat as the leisure bank and one 12 volt 60 amp battery as the cranking battery. I am linking the two with a VSR. The batteries will be charged from the alternator and from a multi stage battery charger of a suitable size when on shore power. I'd be very grateful if you could assist with two questions:

1. As the amperage of the leisure bank and the starter battery is different, it this likely to have an adverse effect on the starter battery when both leisure and cranking banks are linked through the VSR? I thought perhaps the cranking battery might be overcharged?

2. The boat is a beneteau 321 with individual switches for the battery, currently wired for master on, battery 1 and battery 2. Can I incorporate these switches into the VSR installation and are there any advantages to this or would it be better to remove them altogether?

Any help gratefully received!
Click to expand...

I bought a clever 240v battery charger which had charging for two separate battery banks so one output is dedicated to the engine battery and the other to the "domestic bank" which now comprises of two linked 135A batteries.

It's a Waeco.

have a similar smart charger for the solar panel.

I don't seem to have any issues. However I don't have a "clever" VSR for the alternator
 
zambra said:
1. As the amperage of the leisure bank and the starter battery is different, it this likely to have an adverse effect on the starter battery when both leisure and cranking banks are linked through the VSR? I thought perhaps the cranking battery might be overcharged?
Click to expand...

In my understanding overcharging comes from over voltage (over 14,4V) or from prolonged charging at that voltage (days rather than hours). So unless you install some voltage regulator that uses over voltage to speed things up (Sterling) or some crude battery charger that does not float properly, you should be fine.
However, in this recent thread there are some interesting observations that suggest that VSRs are not necessarily the ultimate solution:
http://www.ybw.com/forums/showthread.php?452074-Split-charge-relay&p=5637871#post5637871
 
Last edited:
I have a VSR across my two domestic batteries and was convinced last year that it was running the batteries down. I'm on a swinging mooring so unable to plug in to the mains. However I did find I had a bad connection in my -ve earth cable between the domestic bank and the start battery. The digital VSR uses a very low current in standby mode, but I have noticed through the winter when I have had the boat plugged into the mains to charge the batteries while I have been there is that the VSR gets warm. I suspect this will take a fair bit of the solar output when back on the mooring. I have currently wired a switch into the VSR Earth wire to effectively isolate the VSR. I need to do some tests when I get the covers off on a sunny day.
 
zambra said:
I'm hoping to take shameless advantage of forum expertise! Having read everything I can I'm still a bit confused regarding my reconfiguration of my boat's electrical system.
I am installing two 120 amp 12 volt batteries in my boat as the leisure bank and one 12 volt 60 amp battery as the cranking battery. I am linking the two with a VSR. The batteries will be charged from the alternator and from a multi stage battery charger of a suitable size when on shore power. I'd be very grateful if you could assist with two questions:

1. As the amperage of the leisure bank and the starter battery is different, it this likely to have an adverse effect on the starter battery when both leisure and cranking banks are linked through the VSR? I thought perhaps the cranking battery might be overcharged?

2. The boat is a beneteau 321 with individual switches for the battery, currently wired for master on, battery 1 and battery 2. Can I incorporate these switches into the VSR installation and are there any advantages to this or would it be better to remove them altogether?

Any help gratefully received!
Click to expand...

How about this using a bi-directional VSR wired so that the alternator charges the engine start battery as the priority and the battery charger, solar and wind chargers if fitted, charge the domestics battery bank as priority.

Scan_20160317.jpg
 
Many thanks all for your interesting replies. Its reassuring I wasn't over thinking the issue and that there might actually be a problem. As far as I can see, even with a bi directional vsr (interesting post vicS), for charging purposes, you end up with a single bank of batteries of different amperages and the potential to overcharge the cranking battery. Maybe best just to install in the standard configuration and hope for the best on the basis that any period of overcharging would not last long.
 
zambra said:
As far as I can see, even with a bi directional vsr (interesting post vicS), for charging purposes, you end up with a single bank of batteries of different amperages and the potential to overcharge the cranking battery. Maybe best just to install in the standard configuration and hope for the best on the basis that any period of overcharging would not last long.
Click to expand...

I had a long discussion with Merlin on this point, during which they insisted that this wouldn't be a problem. I wasn't 100% convinced, but since they had specified and were supplying our entire system from alternator controller to batteries, I decided that if it did become a problem I would make sure it was their problem :D. So far, with a 420Ah service bank and 30Ah start battery paralleled for charging, I haven't noticed any trouble.

Pete
 
zambra said:
Many thanks all for your interesting replies. Its reassuring I wasn't over thinking the issue and that there might actually be a problem. As far as I can see, even with a bi directional vsr (interesting post vicS), for charging purposes, you end up with a single bank of batteries of different amperages and the potential to overcharge the cranking battery. Maybe best just to install in the standard configuration and hope for the best on the basis that any period of overcharging would not last long.
Click to expand...

A VSR closes ITYWF at 13.7 or 13.8 v , which is probably about the point at which the battery reaches 3/4 of fully charged. If the big bank is fairly low the volts will drop ( this in itself can be a brief problem if the volts fall below 12.8 and if the VSR cuts out again.)
Once paralleled the two banks will charge together with the one at the lowest SOC getting the lion's share of the amps until both are charged when, if the batteries are the same type, the amps will be distributed according to their size.

The small battery is no more likely to overcharge than it will if connected on its own to the alternator as in a single battery system or even your car. See what pvr has just said!


As an alternative set up to a VSR you could look at Sterling's Alternator to Battery (AB) chargers which will give you enhanced charging if the domestic battery and simultaneous bog standard charging of the engine start battery.

http://sterling-power.com/collections/alternator-to-battery-chargers

A modification of the engine wiring will probably be necessary to separate the alternator output from the rest in order to take it directly to the AB charger

The down side will be that the solar, wind and shorepower chargers will only charge the domestic bank unless they have dual output controllers, or dual outputs in the case of the shorepower charger.

Although ...... I believe auxiliary chargers cane be routed via the AB charger. ........ not looked into that fully.
 
Last edited:
VicS said:
The small battery is no more likely to overcharge than it will if connected on its own to the alternator as in a single battery system or even your car.
Click to expand...

This is true when you have a basic single-voltage alternator regulator; the problem is when you have a smart one that applies a higher voltage for the bulk phase. The starter battery will then be subject to this higher voltage (14.8 volts in my case) even though it's already fully charged, for as long as it takes the service bank to become charged. As I say, mine hasn't shown any problem with two years of this regime, but it doesn't seem ideal.

Pete
 
I'm beginning to think that it's possible to overcomplicate the simple activity of charging your battery. With all these smart devices around, how on earth do you know what they're doing?
 
I spent a considerable amount of time researching the subject last winter and found an interesting article at http://forums.sailboatowners.com/index.php?threads/1-both-2-off-switches-thoughts-musings.137615/ . After much consideration I decided that was the right solution for me! The thread is quite long and needs to be read several times to distil what is being recommended.

Despite the dire warnings on here about the use if a 1-both-2-off switch the set up has worked superbly for me, with the following caveats, I have a small HP engine, I don't use a huge amount of electricity and I am not planning to do a circumnavigation in my current boat.

The solution is simple; I like simple.
 
zambra said:
Many thanks all for your interesting replies. Its reassuring I wasn't over thinking the issue and that there might actually be a problem. As far as I can see, even with a bi directional vsr (interesting post vicS), for charging purposes, you end up with a single bank of batteries of different amperages and the potential to overcharge the cranking battery. Maybe best just to install in the standard configuration and hope for the best on the basis that any period of overcharging would not last long.
Click to expand...

Just to cofuse you even more (Joking)

The fairly basic VSR system you are contemplating will not result in overcharge or undercharge of either Start or House bats. Batteries of the same type require the same peak voltage to reach full charge. A one way VSR simply parallels the two banks as soon as the battery that you chose to be the "sensed by VSR" reaches 13.6 approx volts. The VSR closes,paralleling the two banks the same as if you used a jumper cable. The Alternator/voltage regulator looks after getting both banks (really one bank now) up to 14.2 V (fully charged) & the regulator cuts out as usual.
Yes-there are technical things to consider in mixed battery type & other complicated systems. Your proposed system is not of the complicated variety.
Install the VSR & decide whether you want to charge the Start or House first. There are OPINIONS about this too but it's your choice -both will work.
You can keep your 1,2,both,off multi switch if you like but you may wish to re-wire it.
Here is a basic diagram that I pirated off this forum that uses just on/off swxs & shows the Start as primary battery. You can re-wire your multi swx as an on/off swx but I think you will need an on/off swx to bridge the VSR if you want to use the house bat for emergency starting.
You can also chose the House bat. as primary by taking the alternator charge feed to the house rather than the start.

Sometimes I think folks get intimidated & discouraged from trying a simple VSR by overly Hi Tech comments that don't necessarily apply to a basic system. No offense intended-just advocating Baby Steps-we all had to learn.

Hope you can view diagram in this link. YBF won't let me upload more than 60kb

Try this one VicS https://www.dropbox.com/s/mafmqcmmebzikc9/Boat Battery Bank Wiring & Switching.pdf?dl=0
 
Last edited:
Len Ingalls said:
Tks. I just posted another attempt. I have had problems with Dropbox since I signed up a yr ago. Probably my stupidity.

https://www.dropbox.com/s/mafmqcmmebzikc9/Boat Battery Bank Wiring & Switching.pdf?dl=0
Click to expand...

Ah, you modified my diagram! Thanks for helping to promote the use of two simple on/off switches rather than the ancient 1-2-Both device! :rolleyes:

PS Photobucket is much more user-friendly, and you can include images within your post rather than sending people to a separate link.
 
It's you I stole it from!! I remembered it was pvb or prv.

The on/off swxs are maybe a bit easier to understand when using a VSR because you really need 3 swxs to get the full benefit.
For those that have been using a multi swx,there is no need to throw it out. Part of it can be used as the bridge by re-wiring to save $. But they will still need a pair of on/off swxs one for each bank of bats.

Tks for the tip on Photobucket.

Cheers/ Len
 
You must log in or register to reply here.

Other threads that may be of interest

Refueler
Switch panel setup ?
2
Replies
21
Views
622
Refueler
Refueler
W
Battery suicide
Replies
17
Views
541
Refueler
Refueler
Skipper Felice
Optimisation of the battery charger infrastructure
Replies
1
Views
143
PaulRainbow
PaulRainbow

Share this page

Top