enough batteries

[chriswilliams29]

on my boat i have a 12 volt system twin batteries for each engine,
i am fitting a 12v telly. also an electric anchor windlass do you think i should put a seperate battery in or will the other batteries be sufficient.
i assume one battery on each engine is for starting and the other is for domestics,

 

[halcyon]

What boat ?

Not common, normally one bank engine/domestic the other engine only. Though I have seen cats with seperate systems for each hull,
Ref windless, depends on cable size and length of run, may be better if long run to fit a bow battery. Normal 12 volt television only pull a small current and should be ok, but there again it depends on tele.

Brian

 

[VMALLOWS]

A conventional 12v telly will take somewhere between 5Ah and 10Ah. That's quite a lot and will flatten a typical large boat battery in about 5 to 6 hours. Maybe you have a state-of-the-art LCD type which should be fine? You seem to be a motor boat, so maybe battery power is not a big problem, or you have a generator?

The windlass is not really a big problem because its only in use for such a short time, but you do need to pay attention to the wiring etc, because when operating it is drawing a huge current (similar to a starter motor).

 

[Chris_Stannard]

It depends on how you use your boat. If you use the engines to go from Marina to Marina, and are always on shore power in between all you need is engine start batteries. If on the other hand you want to anchor overnight with the TV, fridge, etc going you need a bank of dometic batteries, seperate from the engine start, which are semi traction batteries. These are capable of delivering fairly low currents over long periods.
You need to do a power budget, how much will you use, in amp hours between engine runs. Ypu then need to calculate on the basis that each of your domestic batteries has about 30% of its nominal capacity, in that it is likely to be charged to a maximum of 80% and you do not usually wish to discharge it below 50%.
This will show you if you have a problem or not.

If you are going to fit a TV try to get one. like the Grundig worldwide, which works off 12 volts, as inverters are a good way of chucking a lot of power away,

Chris Stannard