VSR's - surely they are pointless?

[ianj99]

Split charge diodes + smart regulator sensing the house battery works well for both boat and camper.

Simple ignition switched operated split charge relays will allow heavy current flow from the house to the starter battery during cranking.

So the simplest and best solution IMHO is to activate the relay via an oil pressure switch (normally open type, not the usual normally closed warning light/buzzer type).

(Its simple enough to fit an an additional small relay with changeover contacts to drive the main relay from the existing oil pressure warning light switch)

 

[ditchcrawler]

I tried a VSR from Victron(Cyrix) but it kept switching in and out.That was probably due to the difference in battery capacities as i have a Red Flash starter at 37a/h and a domestic bank at 220a/h.
Anyway after the starter battery is charged I only want to charge the domestic bank not both banks.I reverted back to my 1/2/both switch which does the job that I want.

 

[snooks]

I tried a VSR from Victron(Cyrix) but it kept switching in and out.That was probably due to the difference in battery capacities as i have a Red Flash starter at 37a/h and a domestic bank at 220a/h.
Anyway after the starter battery is charged I only want to charge the domestic bank not both banks.I reverted back to my 1/2/both switch which does the job that I want.

If you remember the to switch it back and forth all the time, of course.

My system is Snook proof, sadly yours isn't as I found out before I bought my VSR

 

[GrahamHR]

So what's this standard charge splitter I have on my D4 engine boat ? A VSR or something different again ? It looks solid state rather than a mechanical of electronically controlled relay. 3 terminals, central one to the alternator, the other 2 to engine and house battery banks. Its built into a pretty big anodized aluminium heatsink casing. It clearly keeps the engine and house batteries unconnected ( there is an override circuit that can be used if the engine battery becomes flat)

 

[JumbleDuck]

So what's this standard charge splitter I have on my D4 engine boat ? A VSR or something different again ? It looks solid state rather than a mechanical of electronically controlled relay. 3 terminals, central one to the alternator, the other 2 to engine and house battery banks. Its built into a pretty big anodized aluminium heatsink casing. It clearly keeps the engine and house batteries unconnected ( there is an override circuit that can be used if the engine battery becomes flat)

Two diodes with a common connection. Works well, but drops 0.65V or so, so unless you use a battery sensing alternator, an Adverc or something similar, you'd don;t fully charge either battery.

 

[William_H]

Two diodes with a common connection. Works well, but drops 0.65V or so, so unless you use a battery sensing alternator, an Adverc or something similar, you'd don;t fully charge either battery.

Except that it may be one of the more modern zero volt drop (or nearly) type splitters. It may use schotky diodes (low volt drop) or Field effect transsitors with low resistance and near zero volt drop. GrahamHR would do well to check actual charging voltage at the batteries and also volt drop across the centre terminal to each outer terminal when it is charging. Some people do have this volt drop without using battery sensing and have batteries at all times not being fully charged. good luck olewill

 

[JumbleDuck]

Two diodes with a common connection. Works well, but drops 0.65V or so, so unless you use a battery sensing alternator, an Adverc or something similar, you'd don;t fully charge either battery.

Except that it may be one of the more modern zero volt drop (or nearly) type splitters. It may use schotky diodes (low volt drop) or Field effect transsitors with low resistance and near zero volt drop.

Would it have a ruddy great heat sink in that case?

 

[ghostlymoron]

"Anyway after the starter battery is charged I only want to charge the domestic bank not both banks.I reverted back to my 1/2/both switch which does the job that I want."
If the starter battery is fully charged, it won't accept any further charge and it will all go to the domestic bank. The system is effectively self regulating. I wouldn't like to return to a manual system as my experience is that skippers DON'T always remember to switch over and occasionally come unstuck. I hope that you never forget. For a good explanation of charging multiple banks look on Tony Banks' site.

 

[ianj99]

Would it have a ruddy great heat sink in that case?

Yes and no. Mosfets behave like a very low resistance and the claim of 'zero volt drop' is false in my view. It varies with current and at high currents - say 50amps and above, it is significant - not that much different from some diodes.

If the drop really was zero or at least, below 0.1v then the heatsink requirement would be minimal so when I see a substantial heatsink on these products, I ask myself, why, shouldn't be needed if the volt drop is zero.

E.g. 100amps with a 0.1v drop is 10watts which means only minimal heatsink, in practice, 100amps with .5v drop = a 50watt heatsink, which is more like what is actually fitted to these products.

Its false advertising to sell a product that, whilst it may be better than diodes, is probably not that much better at full rated current.

 

[sailorman]

"Anyway after the starter battery is charged I only want to charge the domestic bank not both banks.I reverted back to my 1/2/both switch which does the job that I want."
If the starter battery is fully charged, it won't accept any further charge and it will all go to the domestic bank. The system is effectively self regulating. I wouldn't like to return to a manual system as my experience is that skippers DON'T always remember to switch over and occasionally come unstuck. I hope that you never forget. For a good explanation of charging multiple banks look on Tony Banks' site.

the engine battery will only accept what it can take, once full all amps go to the battery that can accept them. after that the charge level will drop

 

[pvb]

Would it have a ruddy great heat sink in that case?

No, it wouldn't. The low-loss splitters can be quite small and discreet. My boat was fitted as standard with a Quick ECS163 low-loss splitter which only has a voltage drop of 0.05V at 20A, and a max volt drop of <0.2V at 160A current. It doesn't seem to generate much heat.

 

[VicS]

"Anyway after the starter battery is charged............
.
.
For a good explanation of charging multiple banks look on Tony Banks' site.

Tony Banks the musician or Tony Banks ( Baron Stratford) the former Labour politician. ????

Perhaps you meant Tony Brooks and his TB training website http://www.tb-training.co.uk/

 

[ghostlymoron]

I thought that was what I said. Thanks for your confirmation.

the engine battery will only accept what it can take, once full all amps go to the battery that can accept them. after that the charge level will drop

 

[sailorman]

I thought that was what I said. Thanks for your confirmation.

even if left on both whilst charging

 

[ghostlymoron]

Vic, you are correct. Brooks not Banks.

Tony Banks the musician or Tony Banks ( Baron Stratford) the former Labour politician. ????

Perhaps you meant Tony Brooks and his TB training website http://www.tb-training.co.uk/

 

[VicS]

No, it wouldn't. The low-loss splitters can be quite small and discreet. My boat was fitted as standard with a Quick ECS163 low-loss splitter which only has a voltage drop of 0.05V at 20A, and a max volt drop of <0.2V at 160A current. It doesn't seem to generate much heat.

32 watts at its max rating.

The installation instructions call for it to be mounted in a dry place with sufficient ventilation to allow for optimal performance and go on to recommend vertical mounting to aid convection cooling and to stipulate that the surface to which the base is fastened must be able to withstand temperatures of 80C.

There is also warning that the external surfaces can become hot enough to cause burns!

 

[pvb]

32 watts at its max rating.

The installation instructions call for it to be mounted in a dry place with sufficient ventilation to allow for optimal performance and go on to recommend vertical mounting to aid convection cooling and to stipulate that the surface to which the base is fastened must be able to withstand temperatures of 80C.

There is also warning that the external surfaces can become hot enough to cause burns!

Yes, it's vertically mounted (I rotated the pic to make it easier to read the label). And it's on an insulated surface. And it's in the engine compartment, which has forced cooling by an electric fan whenever the engine's running. But it hasn't got noticeably hot yet - perhaps because I don't routinely let the batteries get very low so charge current isn't very high.

 

[prv]

The installation instructions call for it to be mounted in a dry place with sufficient ventilation to allow for optimal performance and go on to recommend vertical mounting to aid convection cooling and to stipulate that the surface to which the base is fastened must be able to withstand temperatures of 80C.

There is also warning that the external surfaces can become hot enough to cause burns!

Describing such an item as "low loss" is clearly rubbish, then!

Pete

 

[pvb]

Describing such an item as "low loss" is clearly rubbish, then!

Well, you might think so, but the voltage drop is much less than for conventional diode splitters, and it's probably a more convenient way of charging 3 separate batteries/banks than using VSRs. Anyway, I only posted the pic because of discussion of things with "a ruddy great heat sink"!

 

[JumbleDuck]

Well, you might think so, but the voltage drop is much less than for conventional diode splitters, and it's probably a more convenient way of charging 3 separate batteries/banks than using VSRs. Anyway, I only posted the pic because of discussion of things with "a ruddy great heat sink"!

That was me, and I stick to my belief that something described as

... 3 terminals, central one to the alternator, the other 2 to engine and house battery banks. Its built into a pretty big anodized aluminium heatsink casing....

is more likely to be a good old-fashioned 0.65V-per-junction diode splitter than more modern exotica.