Installing a dedicated engine start battery - what size/type

I have been using a Red Flash 1100 for 8 seasons to start my VP2003 (28HP) engine with no problems using a 1/2/both switch on no1.
It is beginning to loose charge a bit so when I replace it there is what looks like the same battery from various suppliers under the name Odyssey PC1100 Extreme Racing 40
www.mdsbattery.co.uk have this at £160 including postage,the best price I could find.
 
ditchcrawler said:
I have been using a Red Flash 1100 for 8 seasons to start my VP2003 (28HP) engine with no problems using a 1/2/both switch on no1.
It is beginning to loose charge a bit so when I replace it there is what looks like the same battery from various suppliers under the name Odyssey PC1100 Extreme Racing 40
www.mdsbattery.co.uk have this at £160 including postage,the best price I could find.
Click to expand...

Brilliant - just what I needed, thanks :-)
 
skyflyer said:
The problem is that I want to use the start battery for house! I have a 190Ah battery that I effectively keep just for engine starting. Whenever the engine is off, we run off just the No2 battery not 'daring' to run No 1 down!

If the two batteries are connected by a VSR then they will drain equally until both reach the 'cut-off' voltage (12.8v?)and then the remaining battery will continue to drain until flat, if you let it!
At 12.8v the battery is nominally 100% charged - in other words the VSR will disconnect 190Ah battery almost immediately any significant power is drawn from it! Even allowing for variations and errors, I'll be lucky to get 10Ah out that battery before it is 'disconnected'!

Hence the desire to install a third battery, as per my original post, which needs to be powerful enough to turn the engine, bit ONLY has to turn the engine, but small enough o fit in the space available.

So far the Red Flash 1000 or 1000 looks like it will do the job nicely
Click to expand...

I think you have misunderstood the wiring of the proposed VSR.
The idea was, I think, to hardwire the two 190 Ah batteries into one house bank = 380 Ah. The new Red Flash or whatever will then become the starter battery. Then manage charge and discharge by way of the off,1,2,both-switch or possibly by a VSR.
 
BabaYaga said:
I think you have misunderstood the wiring of the proposed VSR.
The idea was, I think, to hardwire the two 190 Ah batteries into one house bank = 380 Ah. The new Red Flash or whatever will then become the starter battery. Then manage charge and discharge by way of the off,1,2,both-switch or possibly by a VSR.
Click to expand...

No I have not misunderstood my own question :-) You are correct that was what I was originally seeking to do

The nature of this forum is that well meaning people, with the best intentions, will start to answer questions that haven't been asked; I don't mind that as often it brings up something that hasn't yet been consider, but it does mean you end up spending quite a lot of time replying to people explaining why what they are suggesting won't suit you or how they have misunderstood the question :-)

In this case (that you quoted) I was responding to a suggestion in the post above mine that i did NOT need a starter battery at all but could simply split the two 190Ah batteries with a VSR!

To get back to the point - how one ends up arranging the charging regime, via VSR, Split Charge or a 1/2/both switch was never up for discussion - it is a separate issue. (although I am happy to receive any views and thoughts, of course)

The real issue was identifying the smallest sensible size for a dedicated starter battery

Thanks anyway and no offence intended to anyone who has 'drifted' from the original question!
 
I have a 1/2 both switch - manual switching, 1GM10. However - the service live is wired to no 2 post, not common.

When switched to 1 - engine starts from and charges 1 battery - but service is still drawing from battery 2.
When switched to 2 - engine will start from and charge bat 2.
I never use Both. The main rotary switch only isolates the engine battery - and seves to switch charging.

You need a separate service isolation switch - I use a car Hi fi 30amp circuit breaker ( cheap )
I can always start the engine off service if I need - but can never draw service from engine bat.
In an emergency I could jump lead it.

All sorts of ways - but this was simple. Just need to try to remember to switch to 2 if motoring any distance. I've been all the way to Ilfracombe on the engine charging the 'well charged' engine battery - duhh.

A sunware 27 watt panel keeps them sweet - through a Maplins 2 bank reguator.
 
nemodreams said:
I have a 1/2 both switch - manual switching, 1GM10. However - the service live is wired to no 2 post, not common.

When switched to 1 - engine starts from and charges 1 battery - but service is still drawing from battery 2.
When switched to 2 - engine will start from and charge bat 2.
I never use Both. The main rotary switch only isolates the engine battery - and seves to switch charging.

You need a separate service isolation switch - I use a car Hi fi 30amp circuit breaker ( cheap )
I can always start the engine off service if I need - but can never draw service from engine bat.
In an emergency I could jump lead it.

All sorts of ways - but this was simple. Just need to try to remember to switch to 2 if motoring any distance. I've been all the way to Ilfracombe on the engine charging the 'well charged' engine battery - duhh.

A sunware 27 watt panel keeps them sweet - through a Maplins 2 bank reguator.
Click to expand...

Seems to be unnecessarily complex. What is the advantage of using the 1-2-both switch as an on-off switch, which seems to be what you are doing? If you have a manual system you have to remember to do 'something' anyway. On your Ilfracombe trip presumably you arrived with battery 2 flat, which you would not have done with conventional wiring.
 
You have just highlighted the main drawback of the 1/2/B manual switch. Me, I go for automatic everything where possible. Remember when you had to pull the choke out on your car or change gear?
nemodreams said:
I have a 1/2 both switch - manual switching, 1GM10. However - the service live is wired to no 2 post, not common.

When switched to 1 - engine starts from and charges 1 battery - but service is still drawing from battery 2.
When switched to 2 - engine will start from and charge bat 2.
I never use Both. The main rotary switch only isolates the engine battery - and seves to switch charging.

You need a separate service isolation switch - I use a car Hi fi 30amp circuit breaker ( cheap )
I can always start the engine off service if I need - but can never draw service from engine bat.
In an emergency I could jump lead it.

All sorts of ways - but this was simple. Just need to try to remember to switch to 2 if motoring any distance. I've been all the way to Ilfracombe on the engine charging the 'well charged' engine battery - duhh.

A sunware 27 watt panel keeps them sweet - through a Maplins 2 bank reguator.
Click to expand...
 
skyflyer said:
No I have not misunderstood my own question :-) You are correct that was what I was originally seeking to do

The nature of this forum is that well meaning people, with the best intentions, will start to answer questions that haven't been asked; I don't mind that as often it brings up something that hasn't yet been consider, but it does mean you end up spending quite a lot of time replying to people explaining why what they are suggesting won't suit you or how they have misunderstood the question :-)

In this case (that you quoted) I was responding to a suggestion in the post above mine that i did NOT need a starter battery at all but could simply split the two 190Ah batteries with a VSR!

To get back to the point - how one ends up arranging the charging regime, via VSR, Split Charge or a 1/2/both switch was never up for discussion - it is a separate issue. (although I am happy to receive any views and thoughts, of course)

The real issue was identifying the smallest sensible size for a dedicated starter battery

Thanks anyway and no offence intended to anyone who has 'drifted' from the original question!
Click to expand...

Agree with everything you say about the nature of the forum and the charging regime being a separate issue and not what you asked about.
(Still think we interpret Tranonas suggestion in post #19 in two totally different ways, though;-)
 
On a cursory reading of the OP s and others posts I am a bit confused. However what I would advocate (said already I think) is to go for a VSR. Disconnect the engine supply and charging wires from the existing 1,2,both switch. Take these both to the new engine start battery. Via a simple high current switch if you want. Connect a VSR between the centre of the 1,2,both switch and the alternator output heavy wire. get a VSR that will also provide high current for emergency start from the house batteries or add in parallel another high current simple switch. Or carry a jumper lead. Obviously connect all negatives together.
So normal operation switch 1,2,both switch to both. Turn on engine battery (if you fit one) all house loads will run only from 2 big batteries. Engine start battery will be isolated except for charging. The 1 or 2 battery option will give flexibility especially if one starts to die. ie youv cna compare performance (capcity) of each battery individually.
A simple VSR (no hysteresis) is not so hard to build if you like tinkering. Start with a suitable relay for charging current then wire up a sensing a nd drive circuit. PM me for ideas.
As for a type of engine start battery. Assuming you have room I would go to a motor facto and buy the cheapest car battery. Due to volume of sales they will be cheapest and most suitable. if you are pressed for space for the new engine battery then go for a sealed tiny high performance one. good luck olewill
 
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