Voltage Sensitive Relay

[adelaidem]

Im wondering if anyone here has had any luck with such thing? http://www.bep.co.nz/showcategory.cfm?categoryid=4
I have had a lot of trouble working out how this unit works and last week for some unknown reason I lost an AGL house battery maybe due to this unit. I do have a smart charger connected to the correct stud of this unit and also now I have a solar panel connected as well.
My worry is does the solar panel need a solar regulator to shut the power off when not needed or will the VSR do this for me? As on a sunny day I have up to 15 or so volts showing on my battery’s which kind of makes me feel I need to dump the charge?? Please and any help with this unit would be much appreciated

 

[nanofkyle]

An older "sulphated" lead acid battery can show up to 19 volts while charging, confirming that it has reached the end of its life! If possible use a hydrometer to confirm battery state. One dud cell is enough to condemn the battery.

 

[Malish]

As I understand a VSR is just an intelligent switch, putting power to your priority battery (start) until charged then switching to the domestic bank. Should the voltage of the start battery fall the VSR switches power back to it. So it is not a regulator as such, just a switch; I would certainly have a solar regulator between it and a solar panel.
Incidentally, when I fitted such a system I simply connected the solar panel regulator directly to the domestic batteries, reasoning that it was highly unlikely that the start battery would need topping up unless I was starting the engine, in which case charging was via the alternator (and in any case I can switch to the domestics for emergency starting).

 

[adelaidem]

Thank you for the help, I do hear the unit switch off and the red light goes out so I assume it does regulate the voltage of the battery but am unsure and this worry’s me.

 

[Malish]

Mine switches at about 12.8V (Pb wet cell battery).

 

[adelaidem]

So do i need to buy a solar panel regulator or is the VSR pritty much the same thing????

 

[Guest]

These particular VSRs enable a charge source to be sent to 2 batteries and separate them for discharge. So a connection is made when the voltage is high.

A dual sensing VSR is just a symmetrical version of a single sense VSR but still only enables the connection when either of the voltages are high.

A solar regulator is a device that stops the batteries overcharging. So a connection is only made when the voltages are low.

You need both types in your system.

On a system a regulator is needed on each of the charge sources. An alternator normally has one built in or a smart regulator can be added outside. All mains chargers have regulators in them. Solar panels should also be used with regulators (unless they are the tiny self regulating type).

How that charge is distributed to the batteries is the job of the "battery combiners", charging diodes or battery switches.

What happened was the industry used the term VSR to describe a product by its operation not its indented use. It would be like using the words "water boiler" for all kettles and all central heating boilers. It would be confusing. Since VSRs are used in many ways such as; regulators, battery combiners, undervoltage safety protection for fridges, over voltage safety devices on sensitive equipment the term should not be used to describe one particular item.

 

[Malish]

The VSR is designed to switch from one battery to another, not on/off. If you are only running one batter bank then I guess you can use the VSR as an on/off switch but the power from the solar cells has to be dissipated - not what a VSR is designed for - I would use a solar panel regulator. In addition, if using two battery banks the VSR will switch from the priority bank to the domestic bank when the priority bank attains say 12.8V but it will then stay with the domestic bank until the priority bank falls below 12.8V. The VSR will not regulate voltage to the domestic bank and hence there is a risk of overcharging the domestic bank if you do not use a regulator

 

[adelaidem]

So I better get back down the boat tomorrow and disconnect solar panel as its going to be sunny tomorrow and by the sounds of things my battery’s may get cooked!

 

[adelaidem]

I have one CCA lead acid battery (engine start and windlass) connected VSR switch 1 and two x100amp AGM batteries (house)connected to VSR switch 2. Charger and solar is connected to VSR switch 1 as per instructions.

 

[William_H]

A solar panel will only cook the batteries if it is large compared to the size of the batteries. So approximately 10 watts might be a max for 100amp hour battery/ies.(without a regulator) Possibly double this would be OK. Dpends on how much sun and this assumes no discharge of the batteries to compensate. The regulator in it's simplest form starts to pass current to ground from the solar when the voltage of the battery exceeds 14 volts.

A VSR as pointed out is no more than a swittch.
We have 2 isolated battery systems, one for engine start and one for services so that if we use lights frig etc a lot, we still have a fully charged battery to start the engine. Now if we want to recharge the services battery from the engine generator we have to connect to the engine battery. Which we can do by a simple switch or the both position of 1,2,both switch.
However we have to remember to connect the batteries together with the switch when running the engine or disconnect (isolate) the 2 batteries when we stop the engine. The VSR does just that automatic connection/disconnection based on the voltage of the (usually) engine battery. The voltage rises when on charge and falls when engine stops.
(Note the engine battery voltage may be low after cranking so the VSR does not operate until the voltage comes up which is when it has been recharged some)
The VSR can also be set to sense the voltage on the service battery as well or in stead of engine battery. This means that if you connect a battery charger to the service battery (or a solar or wind charger) then once the service battery voltage rises then the engine battery gets connected to it to also get a charge.
If you have more than one separate batteries then you can get a VSR to connect multipole batteries together or use additional VSRs.
good luck olewill

 

[halcyon]

That about covers the basic, but VSR's can go further, which is why we adopted powercentre back in the 1970's. They can include a regulator to limit charge voltage from solar panels / wind generators, and low voltage protectection to the service battery. Also link starting to allow engine to start from service battery, and interfacing to stop spikes on service battery from engine starting if the relay is engaged from solar panel charging.


Brian