Yeoman_24
Well-Known Member
What size starter battery would you suggest for a 10 year old, start first time, reliable 28hp Beta Marine engine?
Thanks.
Thanks.
28hp Beta Marine - starter battery size
- Thread starter Yeoman_24
- Start date
pvb
Well-Known Member
Beta recommend a minimum 70Ah, 450CCA, battery. Why not go with their advice?
RichardS
N/A
You could just fit the largest starter battery that will fit in the battery space. Whether that is 80Ah or 120Ah doesn't matter as it's the biggest. 
Richard
Richard
doug748
Well-Known Member
I think a number of people have fitted much smaller than the recommended capacity, particularly those battery styles which deliver a lot of poke. It can be very handy to fit a small battery near the engine, to free up space elsewhere.
I recall that someone with a Sadler 34 did this, it might have been Vyv-Cox, if so he may chip in.
.
geem
Well-Known Member
The problem with fitting batteries close to the engine ( in the same compartment if thats what you meant) is that the battery get hot. 25degC is ideal battery temperature. At 35degC you half the life. At 45degC you half it again.
Stemar
Well-Known Member
Assuming you have plenty of domestic power and some way of keeping things topped up, I would think you could get away with a fair bit less than the recommended size as long as the CCA is adequate, but I'm with Richard - get the biggest you can fit in, unless weight is also a consideration. It certainly doesn't need to be anything fancy, just a bog standard car battery, as it should never get significantly discharged. OK, on an unlimited budget racer, you want the smallest Lifepo battery you can get away with, but not on a cruising yacht.
BabaYaga
Well-Known Member
As already said, if space is no problem, follow the manufacturer's advice.
For my 20 hp Beta I installed a small AGM (Red Flash 1100), because I wanted to make best possible use of the battery compartment. This has started the engine without problems for over ten years now. Although only around 40 Ah, it still meets the CCA recommendation.
For my 20 hp Beta I installed a small AGM (Red Flash 1100), because I wanted to make best possible use of the battery compartment. This has started the engine without problems for over ten years now. Although only around 40 Ah, it still meets the CCA recommendation.
lw395
Well-Known Member
I'd look at the CCA specs for different sizes and see what was a reasonable price from a brand I'd heard of.
Lots of common car batteries are standard sizes like '083' and '114'. Different makes can have different AH and CCa in the same 'format'.
Then look to see what deals are out there.
Last battery I bought, really good deal on ebay, couriered down from Edinburgh, which is bonkers.
If you can get more CCA and more Ah for no more money, it might still start the engine easily for more years.
OTOH an expensive battery will be killed by abuse or neglect just like a cheap one.
Having the terminals in the correct corners so you don't have to change the wiring is a big plus sometimes.
I think Geem's point is valid, getting your battery warm whenever you run the engine shortens its life and also means it really should have a different charging voltage to match the temperature.
Lots of common car batteries are standard sizes like '083' and '114'. Different makes can have different AH and CCa in the same 'format'.
Then look to see what deals are out there.
Last battery I bought, really good deal on ebay, couriered down from Edinburgh, which is bonkers.
If you can get more CCA and more Ah for no more money, it might still start the engine easily for more years.
OTOH an expensive battery will be killed by abuse or neglect just like a cheap one.
Having the terminals in the correct corners so you don't have to change the wiring is a big plus sometimes.
I think Geem's point is valid, getting your battery warm whenever you run the engine shortens its life and also means it really should have a different charging voltage to match the temperature.
LittleSister
Well-Known Member
As has been pointed out, Ah is largely irrelevant for engine start batteries`. You need lots of momentary oomph, but very little capacity. (The opposite to domestic batteries.)
Ensure the CCA is at least what the manufacturer recommends. Add a bit to the CCA requirement so the battery will continue to be serviceable as it becomes aged, so won't need replacing so soon. Don't worry about the Ah, you'll never use it all.
lw395
Well-Known Member
You're not wrong but to be a bit clearer....
Generally batteries have a longer life if they're used at small % of discharge. The voltage under discharge is related to the current divided by the capacity.
For comparable batteries, a bigger one doing the same job will probably last longer. If you're looking at a range of batteries like say Exide AGM car batteries, the next size up will generally have more capacity and CCA rating, the two tend to go together, as a function of plate area. You're quite right, I wouldn't buy a bigger start battery in Ah terms if it didn't have at least the same CCA rating.
When I bought a new battery for my car, I got the longer one which means using the other bolt holes in the battery tray. 15% more capacity, a bit more CCA, extra cost about a beer and a packet of peanuts.
But every year, Lithium becomes more of an option.....
LittleSister
Well-Known Member
But the discharge from running the starter for a few seconds is minimal, almost negligible. Batteries specifically designed for high short-term output don't need big plates nor, judging by mine and other posters' experience, do they suffer from short lives. You don't need much Ah, or physical size, at all for an engine start battery.
For cheap, just buy a normal 'car' battery that meets the spec. If space saving is a consideration for any reason, then the specialised high output, low capacity batteries are excellent for this purpose, though significantly dearer.
For cheap, just buy a normal 'car' battery that meets the spec. If space saving is a consideration for any reason, then the specialised high output, low capacity batteries are excellent for this purpose, though significantly dearer.
PetiteFleur
Well-Known Member
I bought a new engine battery for my 25hp Beta, spoke to Beta and I got what they recommended- can't remember the cca etc. but it was the same capacity as my VW Touran Sport which surprised me - and I fitted it in the engine space but I didn't know about shortened life if it gets warm.
Refueler
Well-Known Member
I use standard car batterys rated for diesels ... of over 80A/hr ..... and I buy 2nd hand ...
I have an 80 A/hr Exide Pro battery as starter in there now - cost me 20 Euros .... 1 year old ... came out of a crashed BMW.
All the batterys I have bought as used have all given sterling service with a couple going for over 5 years each.
I read all the tech that people write .. but at end of day - a bog standard starter battery for an average car is all you need.
Think about it ... our boat engines - many are based on utility / static engines marinised. A 20hp ... or even my 43hp are not exactly same as a 200hp car engine !! so if that battery spins over a car engine ... it can do our boat engines !! (I have to admit though - my Perkins is similar as the old London Taxi Cab engine !).
I have an 80 A/hr Exide Pro battery as starter in there now - cost me 20 Euros .... 1 year old ... came out of a crashed BMW.
All the batterys I have bought as used have all given sterling service with a couple going for over 5 years each.
I read all the tech that people write .. but at end of day - a bog standard starter battery for an average car is all you need.
Think about it ... our boat engines - many are based on utility / static engines marinised. A 20hp ... or even my 43hp are not exactly same as a 200hp car engine !! so if that battery spins over a car engine ... it can do our boat engines !! (I have to admit though - my Perkins is similar as the old London Taxi Cab engine !).
RichardS
N/A
I would suggest that this is not as complicated as it seems.
We're talking about starter batteries like those sold in Halfords as starter batteries for cars. All the average-sized car batteries on display will provide plenty of power for a small 30HP marine engine and these will all be 70 - 80Ah.
If you want more starting security by putting as little stress on the battery as possible, then you can fit a larger physical starter battery up to the size of your battery holder, assuming that is the limiting factor. The larger than average starter batteries will be have a greater Ah rating, around 100 - 120Ah, and probably also a higher CCA rating but it doesn't matter about that 'cos you already have plenty of amps.
My 30HP engines both have 100Ah starter batteries which is a bit oversized but they both lasted 11 years so it's a fair trade-off.
Richard
We're talking about starter batteries like those sold in Halfords as starter batteries for cars. All the average-sized car batteries on display will provide plenty of power for a small 30HP marine engine and these will all be 70 - 80Ah.
If you want more starting security by putting as little stress on the battery as possible, then you can fit a larger physical starter battery up to the size of your battery holder, assuming that is the limiting factor. The larger than average starter batteries will be have a greater Ah rating, around 100 - 120Ah, and probably also a higher CCA rating but it doesn't matter about that 'cos you already have plenty of amps.
My 30HP engines both have 100Ah starter batteries which is a bit oversized but they both lasted 11 years so it's a fair trade-off.
Richard
