Lithium or generator

[vas]

How much water are you heating, or, how frugal are the showers. Its not only how much power to heat the water - but also how much water do you carry. I think the OP was talking of a few days at anchor (then he would move, heating water on the way and making a few more watts, though his DC-DC charger was not large) but water is usually a finite resource - as scarce as watts

Jonathan

hence a watermaker is more important (in the summer!) than a calorifier

 

[Neeves]

hence a watermaker is more important (in the summer!) than a calorifier

They are both greedy users of amps - there is no escape!

J

 

[NBs]

If you are buying new batteries, the better chemistry for boat batteries is Lifepo4, which are much safer than lithium batteries. A DC-DC charger is the cheapest way to charge, the most efficient ones would be a charger regulator balmar/wakespeed which protect the main charger.

 

[BlueJasper]

Thanks for all the responses. No decisions have been made except that a Honda generator is not the answer.

The diesel water heater is an option, but I'll probably wait until current batteries are dead then go lithium, I mean Lifefo4.

I'd still need new batteries in a few years even with the diesel heater and I believe a couple of lithiums, a DC to DC charger and our slow cruise speed will give us enough power for the water.

 

[PaulRainbow]

Thanks for all the responses. No decisions have been made except that a Honda generator is not the answer.

The diesel water heater is an option, but I'll probably wait until current batteries are dead then go lithium, I mean Lifefo4.

I'd still need new batteries in a few years even with the diesel heater and I believe a couple of lithiums, a DC to DC charger and our slow cruise speed will give us enough power for the water.

I think you are mistaken. The batteries only store power. Unless you can generate sufficient power for you needs you'll have to adjust your needs, or increase power generation.

One of the main benefits of Lithium is the ability to fast charge, but you have no fast charge capabilities, so you don't get that benefit. Different story if you were to fit a decent amount of solar.

 

[BlueJasper]

Paul, I think I'll be OK. 1/2 hour heating hot water about 50ah. So first night heated on route, nights 2 and 3 batteries 100ah down. Day 4, move on and with a 30 amp dc to dc charger, about 3 hours later we are there or there abouts. I only cruise at 8 knots. Solar pulls in more than enough for the fridge.

 

[PaulRainbow]

Paul, I think I'll be OK. 1/2 hour heating hot water about 50ah. So first night heated on route, nights 2 and 3 batteries 100ah down. Day 4, move on and with a 30 amp dc to dc charger, about 3 hours later we are there or there abouts. I only cruise at 8 knots. Solar pulls in more than enough for the fridge.

What alternators do you have ?

 

[BlueJasper]

Just 1 alternator, a Deco Remy 130amp. Cruise at 1500rpm on the engine. Could it take 2 x 30 amp dc to dc chargers?

 

[Seastoke]

How do you boil kettle and cook etc

 

[BlueJasper]

Gas for cooking and kettle.

 

[Bouba]

In my humble opinion...running an electric boat is the best (and most expensive option) it allows you to expand into anything you want, microwave, electric blanket, toaster etc etc.....otherwise each upgrade you want to make becomes another hurdle with a unique solution....and possibly when accumulated becomes more expensive

 

[Greg2]

In my humble opinion...running an electric boat is the best (and most expensive option) it allows you to expand into anything you want, microwave, electric blanket, toaster etc etc.....otherwise each upgrade you want to make becomes another hurdle with a unique solution....and possibly when accumulated becomes more expensive

I take your point but in reality electric doesn’t cover all bases such as heating or air conditioning without a generator. To my mind there are better options for hot water in particular but each to their own
.

 

[PaulRainbow]

Just 1 alternator, a Deco Remy 130amp. Cruise at 1500rpm on the engine. Could it take 2 x 30 amp dc to dc chargers?

Yes, 2 x 30a DC-DC chargers should be fine. But, you're limiting your 130a alternator to 30a or 60a, i cannot see how that's giving you more power.

Can you add more solar, or another lead acid battery ?

 

[Bouba]

I take your point but in reality electric doesn’t cover all bases such as heating or air conditioning without a generator. To my mind there are better options for hot water in particular but each to their own
.

I meant diesel generator, sorry if I was a bit obscure....it is a major expense....but after that everything is cheap...because household electrical goods are cheap...and the boat becomes a little appartement rather than camping out

 

[Greg2]

I meant diesel generator, sorry if I was a bit obscure....it is a major expense....but after that everything is cheap...because household electrical goods are cheap...and the boat becomes a little appartement rather than camping out

Yes, I tend to agree but then you do add a noise issue that is very noticeable on the size of boat that we run.

We use gas for cooking and boiling a kettle and have just upgraded our hydronic heating, which also provides hot water, and added additional batteries and switched to AGM which I am hoping to combine with solar panels. With a bit of luck we will be reasonably self sufficient, or at least able to spend several nights away from shore power. We carry a suitcase generator to power the battery charger but I would really like to make it surplus to requirements and crate some space in the deck locker.

 

[BlueJasper]

Oh Greg, you've created another rabbit hole!

I've git an Eber, is adding hot water a new unit or a conversion to it. This sounds interesting!

 

[Greg2]

Oh Greg, you've created another rabbit hole!

I've git an Eber, is adding hot water a new unit or a conversion to it. This sounds interesting!

Unlike most Eber/Webasto/ Planar etc heaters that heat air for circulation, hydronic systems have a different heater that heats water for circulation instead. The water provides heat either via radiators (much like central heating in a house) or via heat matrix/fan units (much like a car). Our boat always had hydronic but we have had the system re-vamped with a new heater, a radiator in our cabin, a towel rail in our en-suite heads/shower and heater matrix’s in other spaces The bonus of such a system is that the hot water tank is also heated by the system. During the summer we turn the heating units off and the system heats the hot water fairly swiftly.

If you were to replace your current system it might be a bit pricey but you could add a water heater such as the Hcalory just to do the hot water. I understand that they are available in the U.K.
.

 

[BlueJasper]

That HCalory could be the answer!

 

[Greg2]

That HCalory could be the answer!

A lot less money than an Ebby or Webasto!