Batteries or small generator?

[Richard10002]

Here goes

The boats a rodman 800. With vp kamd 300. Yes charges batteries but for our running probably an hour or two at a time I doubt it will ever fully charge the batteries

2 not previously but will now. The engine compartment has a dedicated two battery box on a fixed shelf. To add to the bank I will extend the shelf and add a new or bigger box

3 will have to lo at the manual. Will pop to the boat tomorrow to check it out

4 ?

Cheers

Benn

Most boats would run their engine to charge the batteries whilst at anchor - if that's too expensive, or whatever, you need another source of power. I think a Honda Eu10i will power up to a 50A charger comfortably, and it will be fairly quiet, or you could look at a Kipor for less money, and a bit more volume.

If your battery drops below about 12.2V, you will be damaging it, perhaps irretrievably if you do it for too long and/or too often.

 

[CX54WEK]

If you have space I would upgrade your leisure battery bank.

Thats what we did and it has worked wonders. We upgraded to two leisure batteries and a starter which gives us ample power to stay somewhere for two days at a push three without running the engine or dropping below 12.2V.

We have also swapped all of our lighting to LED including the anchor light which has helped.

I think you will find that your cool box is your major killer of your power supply. Thankfully we have a reasonably efficient 12v compressor fridge.

 

[Trundlebug]

Another vote for "Install an extra battery - or two if you have room".

The major advantage is - silence.

The other benefits are -
Simplicity. No need to fetch out the genny, strap it down, wire it up, start it up. Then put it all away afterwards. Every time you stop anywhere.
Space (a genny takes up more space than one battery. Maybe the same as two)
No fuel to add, petrol to buy, extra engine to service / fix
Cost. Leisure battery £70. Genny £600. Difficult decision?
No complaints, sideways glances or nasty looks from your fellow boaters because of the noise. Fewer arguments, more friends!

I can't see how anyone could spend long deciding!

 

[Chris_Robb]

First you need to understand what your batteries are all about.
1. What voltage do they charge at - minimum should be 14.4v for lead acid.
2. You need to know what the voltage is at any time to know the state of your batteries
3. You need to know how many amps certain items use
4. You need to know what the charge rate is when charging.

To do this get a simple clever meter unit such as the NASA BM1 and connect it up to the main house battery.

Then to improve things -
1. Get additional battery amps - suggest you connect your 140 AH engine battery with the house battery, and get a 110 AH battery for the engine. Have the bow truster running off the house battery bank instead.
2. If you are only getting 14.0 V at the batteries when charging under engine, fit an alternator charge controller to boost output to the proper level - it will charge the batteries much much faster.
3. Charge regularly - dont let batteries ever go below 14.2V - it will finish them off very quickly.

If you get a generator, make sure you have a decent sized mains charger unit - a 30 amp one will be too small for a rapid charge, so that will determine the size of genset you need. However if you don't do weekends away from the marina often - just charge with your engine twice a day - 1 hour at a time and save your money. Big engine compared with us rag and stick merchants though!

 

[Trundlebug]

- dont let batteries ever go below 14.2V - it will finish them off very quickly.

EEK! I think you mean 12.4v, typo surely

 

[mjf]

A typical 30 amp charger will draw 30 x 12 x 1.1 = 400 watts. The charging rate will therefore depend upon your charger rather than the genny. Most dual output chargers are smaller than this. 30 AH will probably take around 3 hours to put 70AH back into your battery, as charging is not an efficient process.

Bang on the money. For extended stays away at anchor that's exactly what I seem to need for my 2x140ah jobs with fridge freezer and usual domestic loads. Charges at 50amps and falls to 10/20 amps at COB for the day

 

[Chris_Robb]

EEK! I think you mean 12.4v, typo surely

No - Just I seem to be getting dyslexic!!!!

 

[CX54WEK]

No - Just I seem to be getting dyslexic!!!!

Its usually my fingers that get dyslexic.

My brain knows what I should be typing but my fingers ignore my brain

 

[tommydortez]

i learned the hard way, like yourself (flat batts)... have a 3kw inverter gen now, does the trick even with a fridge on the go. plus it saves all those bloody calculations