Batteries, inverters, power bank questions

[HenryFreeman]

Hey all,

 

Looking for some advice. So I've had the same set of lead acid batteries for about 7 years now and they've basically given up the ghost. And while my boat was in the boat yard getting painted, the inverter went arse up due to being filled with sandblasting sand. So between the two, it's got me thinking about my electrics. Honestly, I don't use a lot of electrical items on the boat outside the lights, fridge, pump for shower, pump for water, bilge pump. Anything like running a laptop, TV etc. I just run off the built in battery (laptop/phone) and the TV is rarely turned on. In fact, I'm pretty sure it's also full of sand and knackered. So I'm beginning to wonder if replacing all the 4 lead acid domestic batteries and getting another inverter would be a waste of money?

 

What I'm wondering is how few domestic batteries I can get away with installing to run the pumps, lights and fridge. 1 would be ideal but I suspect that might not be possible. Lights and pumps fine - fridge as well? Possibly not. I've also got 600w of solar on the roof. The fridge is one of those Inlander 12v conversions.

 

For the money I'd spend on 4 batteries and another inverter, I could get one or two domestic batteries and one of those big Bluetti power stations (https://bluettipower.co.uk/products/bluetti-ac200max) for running any 240v stuff on the rare occasion 240v stuff gets run.

 

Wondered if anyone has any advice/suggestions? What is a realistic minimum based on the above?

 

Just thinking, I'd probably need an inverter of some kind to charge up the Bluetti. But maybe just a cheap and cheerful one rather than a fancy Victron one.

 

Cheers!

Edited December 29, 2023 by HenryFreeman

[agg221]

8 minutes ago, HenryFreeman said:

Hey all,

 

Looking for some advice. So I've had the same set of lead acid batteries for about 7 years now and they've basically given up the ghost. And while my boat was in the boat yard getting painted, the inverter went arse up due to being filled with sandblasting sand. So between the two, it's got me thinking about my electrics. Honestly, I don't use a lot of electrical items on the boat outside the lights, fridge, pump for shower, pump for water, bilge pump. Anything like running a laptop, TV etc. I just run off the built in battery (laptop/phone) and the TV is rarely turned on. In fact, I'm pretty sure it's also full of sand and knackered. So I'm beginning to wonder if replacing all the 4 lead acid domestic batteries and getting another inverter would be a waste of money?

 

What I'm wondering is how few domestic batteries I can get away with installing to run the pumps, lights and fridge. 1 would be ideal but I suspect that might not be possible. Lights and pumps fine - fridge as well? Possibly not. I've also got 600w of solar on the roof. The fridge is one of those Inlander 12v conversions.

 

For the money I'd spend on 4 batteries and another inverter, I could get one or two domestic batteries and one of those big Bluetti things for running any 240v stuff on the rare occasion 240v stuff gets run.

 

Wondered if anyone has any advice/suggestions? What is a realistic minimum based on the above?

 

Cheers!

We have a similar level of appliances. We do charge phones but only whilst the engine is running and I tend to have the fridge turned off if the engine is not running and it is down to temperature - generally get things out of it before mooring up for the evening. We do not have any solar at present. I have switched all lights to LED and most of them are ultra-low energy ones where it is not a working area. They are also grouped so that I can switch off most of them - often there are only a couple of lights on.

 

We run off two small lead acid leisure batteries and have not seen them dip on the monitor below 12.3V. They are now around 3yrs old. There is also a monster starter battery and the bilge pump is connected to that, but apart from periodically testing it, it never runs.

 

I have threatened to go zero-electric. I have added the hand start back on to the engine and now pretty much only use that. When I am on the boat on my own I often use oil lamps and if I add a cool box under the galley floor that will deal with the fridge. I have threatened to add a 5l header tank and a semi-rotary pump to deal with water, but that has been vetoed and I would have full on mutiny from the crew if I removed the phone charger!

 

Alec

 

[booke23]

I guess the more relevant issue is how often do you charge your batteries in winter? Obviously your solar does it during the spring/summer/autumn but what do you do in the winter?

 

If you cruise or run your engine every day then I’d have thought 200Ah of lead acid would be sufficient, but if you want to last a few days between charging you’re going to need a much bigger battery bank. (Observing the 50% discharge rule to avoid knackering the batteries)   

[blackrose]

The advantage of a smaller battery bank of course is that it's much easier to maintain and keep charged - assuming the boat isn't connected to shore power with a battery charger on 24/7. So there's a very good argument for only having a battery bank that suits one's requirements and no larger. 

 

However, whatever size battery bank you buy you need to be able to monitor them and this is where many boaters fall down. They have no idea when their battery bank is fully charged or when it's down to 50% SoC and therefore they have no idea when to charge or stop charging.

 

As far as inverters go I don't know what a Bluetti is but there are loads of small cheap inverters on Amazon. The only issue is that none I have seen there are N-E bonded like a proper inverter to replicate mains power and make sure your breakers work in the event of a fault. I know lots of people use these cheap inverters and I'm sure they're fine, but on the other hand however small they're still producing AC power which can be deadly if your breakers don't work. 

Edited December 29, 2023 by blackrose

[David Mack]

Depends how long you want to go between charges. We had only one domestic battery on Belfast, which was fine when boating fairly long days, turning off the fridge when the engine was not running and being frugal with lighting. The one solar panel was enough to keep the batteries topped up all year when the boat was not in use, but having left the fridge running for 3 days while we were away from the boat in the height of summer, I came back to a flat battery, so the solar clearly wasn't enough to run the fridge!

[Tony Brooks]

4 hours ago, blackrose said:

The advantage of a smaller battery bank of course is that it's much easier to maintain and keep charged - assuming the boat isn't connected to shore power with a battery charger on 24/7. So there's a very good argument for only having a battery bank that suits one's requirements and no larger. 

 

I don't buy that. The ease of keeping batteries charged relates to putting back in what you have taken out and the battery capacity has no effect on that, save, possibly, the self discharge rate. Small LA batteries will suffer the same falling charge acceptance as large LA batteries and the small ones will, for any give discharge, be cycling to a greater depth of discharge. The only advantage I can see is initial cost.

[blackrose]

9 minutes ago, Tony Brooks said:

 

I don't buy that. The ease of keeping batteries charged relates to putting back in what you have taken out and the battery capacity has no effect on that, save, possibly, the self discharge rate. Small LA batteries will suffer the same falling charge acceptance as large LA batteries and the small ones will, for any give discharge, be cycling to a greater depth of discharge. The only advantage I can see is initial cost.

 

Yes it's all about putting back what you've taken out, but perhaps what you're forgetting is that much easier to discharge batteries from 100% than charge them back to 100%. Therefore there is a tendency for larger banks not to be recharged fully. It's obviously easier to recharge a smaller bank fully, hence my previous comment about smaller banks being easier to maintain [properly].

[Tony Brooks]

16 minutes ago, blackrose said:

 

Yes it's all about putting back what you've taken out, but perhaps what you're forgetting is that much easier to discharge batteries from 100% than charge them back to 100%. Therefore there is a tendency for larger banks not to be recharged fully. It's obviously easier to recharge a smaller bank fully, hence my previous comment about smaller banks being easier to maintain [properly].

 

I still don't accept that premise. Given the same current taken out, both banks should recharge in a similar time given the same charge source values.

[HenryFreeman]

Thanks all for your advice! Just to answer a few questions..

 

I've got a portable generator (Kipor 2600) and a Victron battery charger that I use to keep the batteries charged rather than using the engine. So am basically able to charge the battery bank whenever it needs charging.

 

I've also just remembered I've got a small 400w inverter that is used for powering my Morco water heater which might well suffice for charging the Bluetti.

 

The Bluetti is a LiFePO4 power station/battery with a built in 2000w inverter and can power 240v appliances, usb, 12v etc. It's a handy unit (not that I have one yet but have been doing a lot of reading up on them) and possibly a bit more flexible than a traditional lead acid battery bank. Plus you can add additional battery packs to extend it to 8000+ watt hours.

[magnetman]

Crikey those Bluetti things are expensive !!! 

 

3072Wh of battery with some electronics £2,800 !!

 

 

 

 

 

[blackrose]

33 minutes ago, Tony Brooks said:

 

I still don't accept that premise. Given the same current taken out, both banks should recharge in a similar time given the same charge source values.

 

Yes, given the same current taken out both banks should recharge in a similar time, however it's also about how the batteries are used. With a larger bank there's a tendency to use more current because one has more availability, meaning there's more current to put back in. So if you take a 500ah battery bank down to 50% SoC then you have 250ah to put back on to get it back to 100% but if you take a 300ah bank down to 50% SoC then you only have 150ah to put back in. From 50% it's easier to get a smaller battery bank back to 100% SoC than a larger bank. That's all I was saying.

 

With a smaller bank one is likely to be more frugal, charge more often and is more likely to get that bank back to 100% than with a bigger bank. That may result in a battery bank that is better maintained than a larger bank. 

[magnetman]

 

 

In this scenario I would just buy one branded LiFePO4 battery and put it in as a separate circuit to the engine circuit. I would put an AGM starter battery on the engine .

 

Lithium battery to be charged by the solar and the generator. 

 

 

I do this on my off grid Boat. The only power I have, including winter, is from solar. I do use very little power no laptop basically just phone and a light. 

 

Having two separate systems makes sense to me. Laptops don't need inverters one can get 12v DC DC boost converters to charge them with. 

 

 

[HenryFreeman]

2 minutes ago, magnetman said:

Crikey those Bluetti things are expensive !!! 

 

3072Wh of battery with some electronics £2,800 !!

 

 

 

 

 

 

 

Yeah, not getting that one! I'm going for the cheaper one, the AC200 (About £1200).

 

I suppose for the expensive one it's built to be expanded - you can add up to 4 additional battery packs to give you 12000 watt hours.

 

But yes, pricey.

[magnetman]

Not looked into it but with a generator that size perhaps there is a way to shove charge into a lithium battery very quickly somehow. 

 

 

[HenryFreeman]

5 minutes ago, magnetman said:

Not looked into it but with a generator that size perhaps there is a way to shove charge into a lithium battery very quickly somehow. 

 

 

Will do some reading! Might be a cheaper approach.

 

Cheers!

[magnetman]

There do seem to be some quite big chargers around for LiFePO4 batteries. Mostly US products though. 

 

If you could get a 100 amp charger ...  It would probably be quite large. 

 

100A @ 12v is 1200w lets say 75% efficient its still well inside the rating of the genny. 

 

 

Wouldn't it be nice to put in 50Ah in half an hour of genny running !! 

85 amp charger for 12v

 

 

shop.gwl.eu/Chargers/MEANWELL-Battery-Charger-LFP-1700W-12V-85A-Max-14-4V.html

 

 

 

 

 

www.meanwell.co.uk/power-supplies/chargers

 

 

Specifications https://www.meanwell.co.uk/power-supplies/chargers/npb-1700-series

[MtB]

9 hours ago, agg221 said:

I have threatened to go zero-electric.

 

I find "Zero-electric" a a much more appealing prospect than all electric. My first liveaboard was zero electric (other than the 6-cylinder inboard petrol engine), with gas lighting everywhere and a hand-operated Whale pump/tap on the kitchen sink. After a few months I introduced 12v domestic to the boat by fitting a shower with a Paloma, an electric water pump and electric drain pump. A bonus was now we could get a car radio, and later on when we could afford it, a small B&W telly! 

 

Ever since then, 12v has always seemed to me like a luxury on a boat, and 240vac completely unnecessary and overkill. 

 

 

[magnetman]

13 minutes ago, MtB said:

 

and a hand-operated Whale pump/tap on the kitchen sink. 

 

Wasn't this one was it? 

 

goes nicely on a 5L spring water bottle. 

[blackrose]

27 minutes ago, MtB said:

 

I find "Zero-electric" a a much more appealing prospect than all electric. My first liveaboard was zero electric (other than the 6-cylinder inboard petrol engine), with gas lighting everywhere and a hand-operated Whale pump/tap on the kitchen sink. After a few months I introduced 12v domestic to the boat by fitting a shower with a Paloma, an electric water pump and electric drain pump. A bonus was now we could get a car radio, and later on when we could afford it, a small B&W telly! 

 

Ever since then, 12v has always seemed to me like a luxury on a boat, and 240vac completely unnecessary and overkill. 

 

 

 

So in other words you bought a boat without a 12v system, you fitted a 12v system and now for some reason you think a 12v system on a boat is a luxury even though it seems you couldn't live without it? 🥴

[MtB]

19 minutes ago, magnetman said:

Wasn't this one was it? 

 

goes nicely on a 5L spring water bottle. 

 

No, not one of those. It was a later model with a lever on the side one worked back and forth, for which our neighbours coined term "winky-wanky tap", for very good reason.

 

Whale made some very interesting brassware back in the 60s and 70s. 

 

 

 

[magnetman]

One can have a whale of a time with some of their gear. 

 

 

 

I like the idea of charging the phone and illuminating a lamp from a thermoelectric generator running on the back of the fire. 

 

Would be great for times when there really is very little solar power. 

[GUMPY]

Personally I would go for something like this

https://www.fogstar.co.uk/products/fogstar-drift-280ah-leisure-battery

With a Victron Combi.

https://www.wiredcampers.co.uk/products/victron-multiplus-12-1600-70-1600va-1300w-230v-inverter-charger-ve-bus

 

Way more power available and less money spent than one of those pissy power packs.

 

[HenryFreeman]

7 minutes ago, GUMPY said:

Personally I would go for something like this

https://www.fogstar.co.uk/products/fogstar-drift-280ah-leisure-battery

With a Victron Combi.

https://www.wiredcampers.co.uk/products/victron-multiplus-12-1600-70-1600va-1300w-230v-inverter-charger-ve-bus

 

Way more power available and less money spent than one of those pissy power packs.

 

 

Cheers! There is an idea too.

[IanD]

15 minutes ago, GUMPY said:

Personally I would go for something like this

https://www.fogstar.co.uk/products/fogstar-drift-280ah-leisure-battery

With a Victron Combi.

https://www.wiredcampers.co.uk/products/victron-multiplus-12-1600-70-1600va-1300w-230v-inverter-charger-ve-bus

 

Way more power available and less money spent than one of those pissy power packs.

 

 

True, but just be careful with a system like this if you're also charging from an engine alternator -- the first reason is that it's easy to cook an alternator when charging LFP batteries, the second is that if the battery BMS does a high-voltage disconnect to protect itself at >100% SoC and the engine is running, the resulting load dump spike can destroy the alternator and anything connected to 12V.

Edited December 29, 2023 by IanD

[MtB]

17 minutes ago, magnetman said:

One can have a whale of a time with some of their gear. 

 

 

 

I like the idea of charging the phone and illuminating a lamp from a thermoelectric generator running on the back of the fire. 

 

Would be great for times when there really is very little solar power. 

 

What, like in the middle of the night you mean?

 

I've heard of people claiming their solar is so good it collects energy from the moon shining. Clearly complete borrocks though.