Portable power
- Thread starter zoidberg
- Start date
Sea Change
Well-Known Member
It's not expensive to buy quality LiFePO4 cells. You can buy matched grade A cells and a quality BMS (with Bluetooth, obviously) and still come out ahead of some no name 'drop in' battery using unknown components.
I'm not entirely up to speed with current prices, but I know that the cheap off the shelf stuff has only recently become cheaper than the grade A cells I bought five years ago.
fredrussell
Well-Known Member
I saw a Will Prowse video recently where he was saying that there is now not a huge difference in price between buying and building a high spec battery and just buying a good quality (eg Fogstar) battery ‘off the shelf’.
A fogstar drift 230a/h is £590. The Bluetti has 180a/h plus a 2.5kw PSW inverter charger for £900. I wouldn’t buy the latter as it doesn’t suit my needs but it’s not that bad value really.
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Sea Change
Well-Known Member
£500 is actually a good deal if it includes a 2.5kw inverter charger.
Sea Change
Well-Known Member
That's very expensive.
In early 2021 I built my first battery using 271Ah matched grade A cells for just over £400.
I'll have to check what the current going rate is for similar cells but it's supposedly around half that price.
Sea Change
Well-Known Member
Just did a brief bit of googling and it looks entirely possible to build a high quality 280Ah battery for under £200.
A 180Ah power pack obviously has a role to play for temporary or light duty situations, but it's quite a pricey way to add a meaningful amount of capacity on a permanent basis.
A 180Ah power pack obviously has a role to play for temporary or light duty situations, but it's quite a pricey way to add a meaningful amount of capacity on a permanent basis.
PaulRainbow
Well-Known Member
Really, using what components ?
Trident
Well-Known Member
£70-75 a pop for EVE 315AH Grade A matched cells - around £100 for a JK BMS with active balance, add in some wire, some busbars and terminal ends etc and you get all the parts for just over £400 , then its time and electricity to build and charge all the cells in parallel to top balance and then wire up in series. I charge £500 normally to supply and build - so yes £590 for a 230a/h is a bit expensive but Fogstar are one of the good guys - quality stuff and not too expensive . They also do an eco range if you don't want active balance BMS and heat pads.
You wont get the best BMS or cells for under £200 - some vendors have cheap cells at about £45 each and the lowest cost BMS quite cheap too but you'd be pushing it to get to £200 ... I prefer to pay a little more for EVE cells and UK supplied parts but either way LFP is coming down and down in price and the BMS are getting better and better (provided you buy the right ones )
rotrax
Well-Known Member
A bluetti or similar is not meant as a permanent and meaningful amount of power.
As a 'Power Station' it works very well.
I am very satisfied with mine.
Sea Change
Well-Known Member
Even Fogstar only want £45 for 280Ah cells.
When I bought my cells from Alibaba five years ago, it was a fairly lengthy process of searching through forums and Facebook groups to ensure that the supplier had a good reputation. At that time almost nobody was selling cells in the UK.
I'm not sure how low Alibaba prices are at the moment, it's quite a bit of work to determine whether you trust a particular supplier.
PaulRainbow
Well-Known Member
How good are they for £45, when 314Ah Eve cells, from the same supplier are £70 Besides, they are out of stock. Fogstar were out of stock of Eve cells for several weeks, looks like they bought cheap cells in to fill the gap.
You said "entirely possible to build a high quality 280Ah battery for under £200." Even using cheap and nasty cells, you nearly spent your £200 and don't have a BMS.
Searching through forums, Facebook and Alibaba for the cheapest components possible is all well and good if you want the cheapest battery money can buy, but i doubt that equates to a "high quality battery" and you won't even be able to build a crap one for under £200
Trident
Well-Known Member
In fairness to Fogstar they say they are happy with the cheaper cells - its perfectly possible for other companies to make good cells - but when I build packs for my customers or my own boat I don't want to take any risks on quality and as Paul says, for a very small amount of extra cost - £100 for the cells and maybe £50 more for a top of the range BMS compared to a cheap one that has fewer functions and maybe older technology , I can't see any reason to do so.
Perhaps it's worth going cheaper for a shed in the back garden or something like that but around £500 for 300ah seems very reasonable and ensures the best quality. Like for like in AH its only about £150 more than cheap lead acid and probably cheaper than AGM ... in useable AH then its cheaper than even the cheapest LA leisure batteries (you'd need 6 x100Ah in LA) - not to mention 10% of the weight and 1/6th the volume.
Right now I'm putting together the parts for a twin 48v motor system and house bank (with twin Victron 8kw 48v charger inverters) that will allow running two electric motors for many hours and then at anchor it can run 220v for days and days on end with no sun. 3 years ago this would have cost tens of thousands - today the battery bank will be under £5k for 60kw ... 48v is so much cheaper as one JK BMS is needed for each 48v bank (£300 total BMS cost) and 48v inverter chargers are really inexpensive too .
Very off topic I know but it shows just how much these things have dropped in price with mass market adoption.
Perhaps it's worth going cheaper for a shed in the back garden or something like that but around £500 for 300ah seems very reasonable and ensures the best quality. Like for like in AH its only about £150 more than cheap lead acid and probably cheaper than AGM ... in useable AH then its cheaper than even the cheapest LA leisure batteries (you'd need 6 x100Ah in LA) - not to mention 10% of the weight and 1/6th the volume.
Right now I'm putting together the parts for a twin 48v motor system and house bank (with twin Victron 8kw 48v charger inverters) that will allow running two electric motors for many hours and then at anchor it can run 220v for days and days on end with no sun. 3 years ago this would have cost tens of thousands - today the battery bank will be under £5k for 60kw ... 48v is so much cheaper as one JK BMS is needed for each 48v bank (£300 total BMS cost) and 48v inverter chargers are really inexpensive too .
Very off topic I know but it shows just how much these things have dropped in price with mass market adoption.
dunedin
Well-Known Member
Two modest sized semi flexible solar panels will make a big difference, as operating every day.
Sea Change
Well-Known Member
That's not what I'm suggesting anybody looks for. It's about finding which direct from China suppliers are proven to be reliable and reputable.
Anibal
Well-Known Member
Thank you for your suggestion. I will do some research in terms of sizes and what not. The MF895-2 has two sun roof that slides backwards on 3 tracks and that takes 80% of the usable space. The last part of the roof has the anchor light, horn and VHF aerial and on top of that this section of the roof rises at an angle.
lustyd
Well-Known Member
I do think most folks would just pay the small additional cost though as time has value to anyone working or with a family. Spending hours or days sourcing trustworthy suppliers on AliExpress (who may still not be trustworthy) isn’t my idea of value.
Five years ago it was a different equation but now the difference is small enough that building just doesn’t seem worthwhile for most. Especially as insurance becomes part of that equation.
Even just the 10 year warranty seems worth the difference
Anibal
Well-Known Member
For me this was/still is the main driver. I am not savvy when it comes to electrics and stuff, hence my thoughts were to buy an all in one package that I can charge at home and via the portable solar panel whilst on the go and have it ready in case I need to tap on my power supply to keep the fridge or lights going if I have to moor overnight at a location that does not have a power outlet. Don’t get me wrong, I don’t want to splash a grand on a power supply solution if I don’t have to but seeing that we have some small power needs on the boat, I prefer not to use my house battery, which also doubles up as the port engine battery and instead, have a dedicated device to meet our needs. I know I can link the batteries should the port one goes flat but I don’t want to chance it.
Trident
Well-Known Member
I think building packs is still the best way frankly - you know what you are getting and it is lower cost . The big problem as highlighted by the recent BattlebornGate is that companies can do whatever the please inside a plastic case. BB were considered for years to be the best quality manufacturer , claiming to take the best cells from China and assemble in the USA to ensure the best quality blah blah blah - and it turns out that they made poor choices in design and actually produced a dangerous product. There is now a class action law suit underway to try and get the company (who have lost 70% of their market value since this broke) to honour their 10 year warranty - something they seem unlikely to do as it would bankrupt them to replace every battery they have ever sold.
I used to sell Renogy batteries and was very happy with them (their original Smart 100 was very well made with the best BMS at the time and nice thick wires inside etc) but last year when dealing with a Renogy battery from a customer that had failed (not installed by me and in fairness that had been quite wet after he left a hatch open for several weeks ) but when that was written off for a dead BMS and I opened it up to see if the cells could be salvaged I found water inside a "sealed" case that I had to cut open, some rust on screw heads and that was after having to cut it open with a multitool. A new BMS would fix it up but sadly the pouch cells were glued in to the case and that could never be repaired after cutting so a costly recycling project instead...
Building your own pack means no sealed case so access is possible, easy replacement of a cell or a BMS should anything ever go wrong, and most importantly, quality control. I've opened up several well known makes to find things like 200 amp BMS' with a 200 amp discharge rating on the battery and in one case 2X 6mm2 wires to the BMS and in another 1X 10mm2 wire. Neither sufficient to carry that much current and no one would ever know inside a sealed plastic case.
Trident
Well-Known Member
In your case your decision is perfectly sensible. There are other ways but more intrusive and possibly more costly. The house / starter for one engine make life harder ... on a Prestige 35 that has the same system I fitted a 1600w inverter last year for the owner to do coffee etc at anchor and then removed that from the main battery bank this year and added a dedicated LFP battery to the inverter/charger as he kept running things down when away overnight (an electric towel rail to dry things after swimming being the main culprit) . That works great and the charger has two outputs so on shore power still charges the engine batts but over all, its about £1000 which is more than a portable would cost you - it worked well for my customer who needed it all hidden away in the systems room and more power for his fancy pod coffee etc but if the portable has the capacity of inverter and battery that will cover what you want it's really hard to fault it being a couple of hundred quid more for the ease and convenience it offers. Just choose a good reputation brand like Jackery or Bluetti and you wont go wrong
fredrussell
Well-Known Member
Trouble is, do you know what you are getting?. I wouldn’t be at all surprised to find there are very realistic fake Eve cells being made, in the same way that there are plenty of very realistic copies of the quality 18650 cells.
As for cost, last time I priced up making a battery from quality components on the Fogstar site, it worked out only a tad cheaper. As I mentioned earlier, there’s a Will Prowse vid where he’s saying there’s little saving to be had now by self building. The main driver for me would be that if self building you can at least make a battery to fit a space well, and obviously your point about serviceability is a good one.
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