ghostlymoron
Well-Known Member
Charging for 9 hrs doesn't mean it's no good. It depends on the initial state of the battery and the output amps of the charger. For example a 100ahr battery at half charge will take up to 25hrs with a 4amp charger!
Correct battery?
- Thread starter single
- Start date
single
Well-Known Member
Its a 20A charger and i'm assuming the 85 on the battery is 85Ah. It almost started the engine before i brought it home to charge.
William_H
Well-Known Member
Firstly regardless of the amp rating of the charger it is what is actually goijng in to the battery that matters. So use an amp meter. Quite likely only around 4 amps or so which as said will take a long time to recharge a 100AH battery. To give you an idea 100AH battery will be pretty heavy to remove and carry. Not impossible though.
Regarding specialised engine start batteries. These are optimised for lowest cost and lightest weight (smallest) with max current supply capability.
Now if you have a big (weight and size) battery optimised for deep discharge (leisure or what ever it is called) it will still easily provide the start current and probably for a longer time. So no real problem in using a leisure battery to start a small engine. However if you need to buy a new battery you may choose to buy a specialised start battery usually much cheaper because of the mass market for cars. However you will not have the capacity for long use of lights etc that you will with a leisure or deep cycle battery. But then if you want large capacity for lights etc on a boat, then best to have 2 batteries, an engine start and a leisure battery so you can discharge the domestic battery while quarantining the engine start battery for engine start only. good luck olewill
Regarding specialised engine start batteries. These are optimised for lowest cost and lightest weight (smallest) with max current supply capability.
Now if you have a big (weight and size) battery optimised for deep discharge (leisure or what ever it is called) it will still easily provide the start current and probably for a longer time. So no real problem in using a leisure battery to start a small engine. However if you need to buy a new battery you may choose to buy a specialised start battery usually much cheaper because of the mass market for cars. However you will not have the capacity for long use of lights etc that you will with a leisure or deep cycle battery. But then if you want large capacity for lights etc on a boat, then best to have 2 batteries, an engine start and a leisure battery so you can discharge the domestic battery while quarantining the engine start battery for engine start only. good luck olewill
theoldsalt
Well-Known Member
I have always used "leisure" type batteries in my boats for engine starting (all 1.5 litre diesels - 35hp).
Providing they are looked after they will have enough CCA to start this size of engine. I've never found the need to pay extra for an "engine start" battery.
ghostlymoron
Well-Known Member
You won't pay a premium for a start battery, they're cheap as the proverbial due to the large number sold for cars. One suitable for a small diesel car will probably do and last for up to 10yrs or more because it is always kept fully charged by the engine.
theoldsalt
Well-Known Member
I agree if you have room for a dedicated engine start battery in addition to the domestic batteries. However with limited battery space, I use one or both of my domestic (110Ah) to start the engine. An engine start battery (ex car) will not last long if used for dometics and at 110Ah would be more expensive than a "leisure".
single
Well-Known Member
Before i fit this new battery, is there any reason why the original was good one day then completely wrecked the next? I don't really want to wreck the new one! The only odd thing was before it died i had left the leisure battery master switch on for a few days by accident.Surely that shouldn't matter as they are separate systems?
A battery is a battery in the sense you are using one, just what is a 'leisure' battery anyway, this article makes a lot of sense and I know it has been argued about previously: http://www.sterling-power.com/support-faq-2.htm
sarabande
Well-Known Member
There may be a unit, connected to the battery, which is upstream of the battery switch. e.g. an auto bilge pump or alarm. Are there any small cables clipped to the terminals and heading off somewhere ?
If you have a clamp ammeter, you can check to see if amps are still scudding around the elec system (when officially switched OFF). Even a small flow could bring an old battery below recoverable voltage.
sarabande
Well-Known Member
VicS
Well-Known Member
Sometimes they just die. I had had it happen with a car battery. Perfectly OK, then one morning absolutely dead and unchargeable. Must admit, though, not as young as two years.
The article is pretty factual, hardly hyperboli to point out the benefits of lead acid batteries, and that boaties are often ripped off when purchasing them, I found it highly illuminating, perhaps some forumites may indulge in hyperboli in pursiut of their personal opinions and beliefs, but thats what makes this site so interesting and always informative.
lpdsn
Well-Known Member
I find my dedicated engine start battery is dwarfed by the domestic batteries. However it is very good at what it does - starting engines - and it does nothing else. It was also cheap at the auto factors (which is in an industrial unit not on the high street). By cheap I mean a little less than 10% of the cost of my domestics.
Are you sure you can't re-arrange things?
William_H
Well-Known Member
+1, I have 2 different car batteries fail to start the car. just minutes after a medium length drive ie a decent charge. When they die they just curl up their toes. olewill
