How Long Should it Take to Charge House Batteries?

[barnakiel]

I too can recommend NO mixing of new and old. If some old are gone, make the bank shorter and then when the remaining capacity is too low for your needs, replace the whole bank.

b.

[Cheechako]

Originally Posted by carstenb

you can't mix batteries of type or age (don't ask me how I know this). If you change batteries you have to change them all at one (assuming they are interconnected)

I just just have never held to this philosophy. Mixed them many times with no apparant ill effects. I suppose it's correct in theory, but in the real world maybe two "identical" batteries arent the same anyway...?
I've mixed gels with wet cells, 2 yr old 8D with new group 27's etc. The reality is most of these batteries are living their life undercharged...a basic reality for many cruisers... and theorhetically "wrong"....
Just sayin.... it aint the end of the world to mix them. However, if two of four have gone bad... I would change them all also.... if they were the same age batteries...

[goboatingnow]

Originally Posted by carstenb

You don't note how big your house bank is, but I'm guessing it is 4 x 96 AH. This is what I have on my 40 ft Jeanneau. I've never run the bank empty, despite being on the hook for 4 days, meaning no charging at all.

You need to put a meter on the batteries, but from your description, they're shot. Replace them. And do yourself a favor, buy as big batteries as can fit in the battery box.

You should never run your engine at idle for that long. Diesels need to run and get HOT. Idling for that long will burn out the engine.

By the way, you can't just install extra batteries, if the house banks are connected to each other the batteries need to all be replaced and new additions come on at the same time (don't ask how I know this ) If I were you and the space is available, I would drop in something like 4 X 180 AH AGMs. That will give you lots of power. While you are at it, add a couple of solar panels and you'll never need to worry about electricity again.

If you haven't already done so, change out all your light bulbs (including navigation, steaming and anchor) with LED. They are expensive, but after you have changed, you'll use virtually no power

Good advice except ignore AGMs , no use on an average boat and have drawbacks

Dave

[skipmac]

Originally Posted by goboatingnow

Good advice except ignore AGMs, no use on an average boat and have drawbacks

Dave

[hellosailor]

Go to the local chandlery or online and buy two of the books on twelve volt boat systems. They'll give you a more complete picture of the entire SYSTEM because looking at just any one or two pieces will pretty much ensure you miss some important parts of the bigger picture.

And take a look at the forum archives, here and elsewhere, with that bigger picture in mind. All the questions have been asked and answered many times before, the whole point of a forum is that the answers are already there, posted forever, for anyone who bothers to look for them.

All the rest is simple math, amps in and amps out.