Engine start battery

webcraft

webcraft

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Current battery set-up is 1 x 110AH leisure battry for domestic and the same for dedicated engine start.

Am going to use the 2 110AHs as a domestic bank so need a new dedicated engine start battery. Engine is Beta 12.5HP.

What do people recommend?

- W
 
I use a 85Ah leisure battery which is fine. makes it simpler to charge as it is the same as the domestic batteries. A smaller one with more grunt will be fine as well.
 
webcraft said:
.
Current battery set-up is 1 x 110AH leisure battry for domestic and the same for dedicated engine start.

Am going to use the 2 110AHs as a domestic bank so need a new dedicated engine start battery. Engine is Beta 12.5HP.

What do people recommend?

- W
Click to expand...

Just find a good auto factors and buy a starter battery. Mine is 55Ah (can't remember the CCA off the top of my head although for a starter battery it is important) and it has no difficulty with a 4 cyl 48hp Yanmar. It cost IIRC under £60 from a back street auto factors that targets trade customers but doesn't actually eject members of the general public.

Absolutely no reason why the starter battery has to bear any relationship to the domestic batteries, they're for two separate purposes.
 
Or if space is short consider one of the specialist starter batteries with a CCA no less than the typical CCA of a small car battery .

Red Flash for example
But check the CCA of Red Flash batteries on the DMS Technologies website as there are some incorrect figures quoted on some suppliers websites
 
VicS said:
Or if space is short consider one of the specialist starter batteries with a CCA no less than the typical CCA of a small car battery .

Red Flash for example
But check the CCA of Red Flash batteries on the DMS Technologies website as there are some incorrect figures quoted on some suppliers websites
Click to expand...

Space IS short, so a small (physically) battery would be good.

- W
 
webcraft said:
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Engine is Beta 12.5HP.

What do people recommend?

- W
Click to expand...

Didn't know Beta did a 12.5hp. Presumably you mean 13.5hp (BZ482, also known as a Beta 14).

The Beta manual tells you the CCA (cold cranking amps) you need. The AH (amp-hours) rating is not very important for a starting battery, as starting a battery takes surprisingly few AH - it is the ability to put out a very high current for a short period of time that is important, which is what starting batteries like Red Flash are designed to do.

We have a Red Flash starting battery for our Beta 13.5hp. I can't remember which size it is but can check if it would help. The battery is quite amazingly small (unlike the price!) , but always easily starts the engine unless the temperature is around zero, when it struggles a bit if the engine hasn't run for a few weeks.

The Red Flash battery that was on the boat when we got it failed a while later when a cell shorted out. We managed with a leisure battery for a while, but the space we had for the engine battery was so small the leisure battery had to sit on top of a spare berth, rather than under it. In the end I decided that the wiring and other complications in putting a battery elsewhere just weren't worth it, so bit the bullet and bought another Red Flash, and it's been working fine since.

By the way, there will probably be people coming along in a minute telling you you mustn't mix battery types off the same alternator unless you have some fancy split charging system to give different charging voltages to the two batteries. We were told this by various people when we were trying to work out what had gone wrong with the old Red Flash engine battery (the domestic battery is a big AGM). I spoke to Merlin/Powerhouse (who had supplied the batteries and otrher electrical kit we inherited), who were extremely knowledgeable and helpful, and were adamant that the different battery types we had were not a problem and did not need different voltages - they said they would sell us a system to give different voltages if we insisted, but that we really didn't need one.

So it has proved with the replacement battery, and we've never had a problem since (seems we just had a random cell failure of the old battery). (In our system, the alternator charges engine battery first, and when voltage reaches 12.8v a voltage sensitive relay cuts in the domestic battery too.)
 
webcraft said:
.
Current battery set-up is 1 x 110AH leisure battry for domestic and the same for dedicated engine start.

Am going to use the 2 110AHs as a domestic bank so need a new dedicated engine start battery. Engine is Beta 12.5HP.

What do people recommend?

- W
Click to expand...

get a good tractor battery 900 crank 96 ah for the engine, acid or gel no difference, then a good leisure battery try buying a 240 ah for a bus if you have the space its cheap too and can be used as a start if power fails on the engine with no worries.
 
ukmctc said:
get a good tractor battery 900 crank 96 ah for the engine, acid or gel no difference, then a good leisure battery try buying a 240 ah for a bus if you have the space its cheap too and can be used as a start if power fails on the engine with no worries.
Click to expand...

Why on earth would you need a "tractor" battery of that size to start a little 600cc engine? That is smaller than the smallest car engine so a simple small car battery will do, or a Red Flash, which is even smaller both physically and capacity, but much more expensive.
 
The smallest Red Flash, the 900, will start my Yanmar 3GM30. There is not a great reserve of power but for a single cylinder engine it would probably be OK. Go up a size for greater peace of mind and lighter wallet. As has been said, it is a very small battery that will fit in a compact space, such as in the shaft tunnel.
 
If the engine spec calls for 350-400 CCA then the Red Flash 750 will be suitable. (CCA=380 @ -18C )

Next one up in the range is the RedFlash 1100 with a CCA of 500, not 1150


Like I said earlier check the specs on DMS Technologies own website!
 
VicS said:
Like I said earlier check the specs on DMS Technologies own website!
Click to expand...

You did indeed! :o

Seems Merlin Powerstore don't do Red Flash's any more (hence why I was looking at less reliable places elsewhere on the net), but now sell Odyssey brand starting batteries. From a quick look these seem a similar kettle of fish but significantly cheaper. http://www.power-store.com/?id=214 (No connection other than as a satisfied customer.)
 
LittleSister said:
Didn't know Beta did a 12.5hp. Presumably you mean 13.5hp (BZ482, also known as a Beta 14).
Click to expand...

Yes, sorry, BZ482 13.5HP

LittleSister said:
We have a Red Flash starting battery for our Beta 13.5hp. I can't remember which size it is but can check if it would help. The battery is quite amazingly small (unlike the price!) , but always easily starts the engine unless the temperature is around zero, when it struggles a bit if the engine hasn't run for a few weeks.
Click to expand...

Red Flash sounds like the way to go, but they are expensive.

Thanks again.

- W
 
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