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I was toying with running both 12v and 24v systems, but I've decided to stick with 12v throughout. Have just been offered a good deal on a B2B so that might be the way to go, rather than reconfiguring the MPPT.

Thanks both. 200w in to a 12v system, I know in theory that's about 17A, but I also know that a) the voltage will be higher, and b) the panels won't actually reach full output often if at all. So I guess 15A would be fine. In reality, if I went 10A, would I actually be losing any power? Boat...

I'm going to be running two systems on my boat- 200w at 12v feeding a lead-acid bank, and a 600w, 32v PV array feeding the LFP. The smaller system is primarily equipment that is only used when actually sailing, e.g. autopilot, instruments. Once I am anchored up I may want to tap in to that extra...

Thanks as ever Snooblers My 100w panel has 22.6VOC and 19.35VMP The 130w panels from the same supplier are 21.74VOC and 18.00VMP. Would you say these figures are close enough for me not to worry about it? I hear what you say about getting rid of the 100w panel I already have to simplify things-...

I've been reading up about mixing different sizes and specs of panels and getting fairly confused. I've already got a 100w 12v panel, but want to upgrade to a total of around 800w. I'd also add a new MPPT. If I buy more 12v panels and want to run everything through the same SCC, should I buy the...

Thanks- still very new to this and a lot of what I've learned has been from the Nordkyn articles. Clearly there's a lot more to it than I had interpreted. I will amend my previous post. EDIT: it seems I can't edit my previous post, maybe I should report myself and get a mod to do it...?

http://nordkyndesign.com/practical-characteristics-of-lithium-iron-phosphate-battery-cells/ "Memory effects in LiFePO4 cells were discovered and studied by Sasaki et al. [6] and the results published in Nature Materials in 2013. The authors illustrated that, under specific circumstances, the...

There is supposedly a type of memory effect with LFP, where the voltage rise usually associated with reaching full capacity starts to happen earlier and earlier, if the cells are not fully charged. Whilst the cells have not permanently lost capacity, this effect will fool chargers into thinking...

I haven't actually bought the Epever yet, but was planning on the Tracer 60A, partly based on Will's reviews. Just a thought about the BMS... I reckon I could couple an Overkill with a Tyco relay... total cost might not be much more than a Daly, but higher total current capacity (500 Vs 300A)...

I'm trying to put together a 12v 280Ah system without breaking the bank or over-complicating things. It's as a standalone house bank on a yacht, charged by 60A solar (and if necessary, 30A B2B from the engine/SLA). It will power the fridge, inverter for the galley, and a few smaller loads, but...

OK so I've stumbled across a 3kw inverter that is nicely in budget and has a LV alarm at 11.5v, and shutdown at "10-10.5v" which is a bit ambiguous but no worse, potentially, than the others in this price range. I think I may have found my cells supplier. Next up, BMS- Daly being the obvious...

Well that's nice! And did you get charged for 4, or 8?

Thanks. Even the really cheap units tend to have these, but the preset values are a bit wide, especially LVD which is usually just 10v. Mind you I'm finding the LVD for the Daly might be the same value so it would be a toss-up which one would kick in first. A Victron battery protect has a 12v...

I've looked in to the Daly units and some of the reviews/comments aren't entirely favourable, e.g. failing fans and inability to deliver the claimed current. I guess I could generously over-size and go for a 300A unit? Or accept that I'm cheaping out and taking a risk with my cells :o I'm...

@snoobler yes we're UK based (for now) so 230v. Plan to leave next year on an indefinite cruise. The budget can be somewhat flexible, but there is an entire boat to kit out and lots of priorities to balance. My default position is £700 for a bank of 4 Trojan deep cycle batteries, but I think I...

Thanks snooblers, I do appreciate your help. I ran the numbers on the energy audit and I don't think I'm too far off the mark. It suggested just over 1kw PV, which I can't quite fit on the boat. I'm planning 800w, I could squeeze in another 300w I suppose but it would be in shade a lot of the...

I'm planning on a 12v 280Ah system, and want to run some 240v equipment- the most demanding being a 1600w induction hob. So I'm planning on running a 2000w PSW inverter at least. Ideally I'd like to be able to run as much 240v as the batteries can safely take, but 1600w is the bare minimum. I'm...

Not my own first hand experience but this is what happened to somebody's batteries when overcharged, without a BMS: http://nordkyndesign.com/wp-content/uploads/2015/09/EV-Fire-February-2009.jpg

Is the van alternator her only source of electricity?

Thanks for spotting that. I don't particularly want to limit myself to a small cell that must discharge at such a high rate, but the cells that are available in the 50-100Ah region seem very close in price to the 200Ah+ cells and just seem like very poor value. Unless, of course, my ideas about...

Thanks, valid points. But a very large part of my thinking is that lugging a lead-acid on and off the dinghy regularly to is going to get pretty boring pretty quickly. My absolute ideal outcome for this project would be a tiny but powerful battery pack that be attached to the motor itself, and...

What do we think of this deal? https://www.aliexpress.com/item/1005001314797662.html?spm=2114.12010615.8148356.63.5bd5629at97wxk They're only 32A cells but supposedly rated for "3-5C" discharge so 53A on the trolling motor should be no sweat... if you believe the numbers. Seller seems pretty...

Yup I know that option 1 is a good way to ruin my cells, so that's off the table. It seems like with a really good system, you could remove the BMS and everything would still work, i.e. it's a completely separate backup protection system. To play devil's advocate, at what point will we consider...

Had a play around with my trolling motor today for the first time. It took a fair dent out of a brand new and fully charged 110Ah leisure SLA. Would really like to go lithium as soon as possible, as I think the voltage will hold up much better. So here's my latest idea- remember this will...

Thanks- that confirms what I had read about the BP, it's not really designed for this. I could upgrade to the Sterling Pro-Latch, a bit more costly but still within budget. I could also hack the inverter, but I don't know if the relatively cheap Renogy (or any others at that price point) would...

Trying to narrow down on my design. Here's what I'm thinking: 800w PV->60A MPPT Epever-> 4S 280Ah with Daly 100A BMS -> 220A Victron Battery Protect -> 2kw Renogy PSW inverter All at 12v. Smaller loads will run straight off the BMS, not through the BP. Loads will include a Sterling 30A B2B...

Thanks. Just to dlarify, do you mean option 3 above, or option 2?

Thanks. I didn't list no-BMS as one of the options, I was just thinking of using smart devices that can sense whole-pack voltage, and the BMS would be a second layer of protection, with the benefit of cell-level voltage data. I would like to run some higher power loads- the biggest single one...

OK to show just how new I am to this I have some *really* basic questions about battery protection, to see if I'm understanding this properly. 1- simplest option seems to be use the BMS itself as the cutoff device on both charge and load sides. 2- better is to use the BMS to trigger separate...

I'm planning on only having a couple of outlets for the inverter, so that it's impossible to run too many loads. There should be no problems with unexpectedly running out of power for nav stuff, because that's all staying exactly as it is on the lead-acid bank, and the two banks won't ever be...

Looking for any feedback and advice on my ideas on upgrading the electrical system on my yacht. Currently I have 2x110Ah FLA house bank and 1x110Ah SLA engine start bank. Connected through a 1-2-both isolator. Charging sources are the alternator, plus a Marlec PWM charge controller. Originally...

http://nordkyndesign.com/practical-characteristics-of-lithium-iron-phosphate-battery-cells/ Read the section on "memory effects".

I'm new as well but I'm pretty sure you want to get more than 75% in to those cells. I have read that repeatedly undercharging can lead to premature voltage rise which can trick charging sources in to thinking that the cells are full when they are not. It's a type of memory effect, but one that...

Still mulling over options for this project. One very easy route would be to buy a ready-to-go battery like this Hard to beat on price - 60Ah, some sort of BMS built in, charge indicator, and it comes in a waterproof enclosure and has a charger- all for £234. I'm sure the BMS will be pretty...

Thanks, I hadn't thought about idle consumption on the inverter, which might lower efficiency somewhat. I'm juggling with different ideas about where to connect up loads and chargers on what will almost certainly be a mixed FLA/LFP system. It seems that simply running them in parallel is a...