Batteries, what type?

[Guest]

I know there are many for many assorted uses but for a 30fter doing long distances that is both a low user of power but also a low charge of power, what we thinking?

 

Cost isn't the most important selling point, reliability will come 1st, ability to have a love hate relationship with things that charge batteries, physical size and if there is a big difference weight will be considered before price. Batteries are one thing knot worth being a squeaky arse over in my books.

 

The charging ability we'll have -

Off the outboard, 6 maybe 9 amps max

40W solar panel so 4 amps there if everything is perfect.

At sea a 1KW Inverter genny. Can do 8.3 amps DC and can plug a battery charger in to the 240V. This is the last resort option for when things get real low and need a good kick in the slats.

 

Power users aboard -

The usual suspects but all have been tuned to be a low in requirements as possible. The new lights a huge 30 milliamp each, Oh Yeah

At sea basic instruments. GPS/Plotter part time (they fecking annoy the crap out of me so get turned off a lot). Tiller pilots which have proven pretty economical as she's doesn't need any hard tiller wiggling. Satph charging. Sexy nav light that's LED and automatically turns on when it goes dark but more importantly turns off when the sun comes up**. Fridge maybe (verified to use only 1 amp average when running at temp). I think the rest falls into 'want' rather than the above which is more 'need' so wants can wait if power is running low.

 

Std lead, Glass mat, Lithium thing-a-me or ?????

 

One other thing. Instead of say 1 at 100Ahr would 2 at 50Ahr be better?

 

I am targeting around 125-160Ahr storage, played very carefully I can stretch that out to a few days worth of essentials with no input. Just trying to balance the mid ocean requirements with the mid Akl harbour ones.

 

** - better get the shameless plug in now IT is the new sites owner

The sexy LED light was supplied by Neptune's Chest, a photo of it pops up on the left occasionally. Purchased as the word 'Brazilian' came up a bit, IT was right, the light is 100% hair free

[tuffyluffy 76]

Cant speak for the fancy pants batteries, but bang for buck, the 4, 6volt lead acids on my boat just keep on giving. I think they sell as golf-cart batteries.

 

Nice big plates that love deep cycling. I think i get 440AH at 12v, so two of them should give you 220AH at 12v.

[Island Time 1,235]

For performance/weight you cannot beat the lifepo4 batts. The solar place in silverdale has them, and you must buy the matching charge controller. He sells them on trade me as well.

2nd choice is AGM hybrid gels. Way cheaper, but heavier. Not sure you are still allowed wet cells for cat 1, there was talk that gels would be required.

I can give more info when not writing this on my cell! Give me a call if you want to discuss.

[wheels 543]

It doesn't really matter if you have two at 50Ahr or one at 100Ahr. It is still 100Ahr. It really comes down to the physical size and how and where you want to sit them/it.

So type (as in FLA, GEL, AGM or Lithium) aside at the mo, the big issue you need to consider is getting that 160Ahr back into the Battery bank. Consider it this way. Lets go for your lower figure of 125Ahr of usable storage. To fill that back up, (leaving inefficiencies and charging curves out of the picture for just the mo) it will take 10hrs of charging at 12.5A or 25A for 5 hrs, or 50A for 2.5Hrs. So how long do you want to run the Charging equipment for???

Lets say you get really good Sun every day (and I am being very generous here) you might get 24Ahrs back in. In reality I doubt it. That means you still need to find 100Ahrs from somewhere. That's 10A for 10hrs or 20A for 5hrs or 40A for 2.5hrs. Get the picture

Next part of the problem. The 8A DC from the Outboard and from the Inverter will be regulated probably at 13.8V. That is fine for a wee battery to start those two units with, but no good for charging and they most likely will not combine to share the load each. One will do all the work and the other will skive off and laze about. At 230V, the 1Kw genny will run a Battery charger capable of delivering about 50A. You might squeeze more from it, but it's pushing the genset hard for several hrs.

OK so that's the good news. The problem part is, Lead Acid batteries won't take a full rate of charge all the charging time. Lets say you get a 50A charger. I said above that would get you 100A in 2hrs. But the problem is, as the charge comes up on the battery, the current it draws drops away. So the charging time will be much longer than 2hrs. It could be 3hrs or maybe slightly more to get the bank all the way up to a full charge. Or otherwise you won't get 100Ahrs from the battery on the next discharge cycle.

This is where Lithium Ion has an advantage. First off, they can weigh about 80% less than a Lead Acid battery. The other advantage is that it can take a full charge current all the way to fully charged. So the shortest charging time. But that will still be 2hrs of charging remember. But these batteries are really really expensive and they need their own dedicated (expensive) charger and I am not sure what happens about the Solar panel in that case. As in, if it needs a special Lithium charge controller, which I would expect it would. Putting it another way, it would probably be cheaper to take a heap of Lead Batteries, one for each day and when one is flat, you throw it overboard and use the next one and so on

The good news though, I don't think you are going to be using that much power. I would only be running the Sat ph when you need to make a call Home and when you down load your weather etc. You might find that it would last the entire trip on it's own charge. Same with GPS. The two biggies will be Fridge and AP. How badly do you want cold Beers??? I suggest that instead of deep cycling the batteries down low and then charge once every 3 or 4 days, you charge each day and thus keep the charging time as short as possible and charge the Sat ph at the same time as the battery charger is running.

[Island Time 1,235]

What wheels said!

My brother just priced 400ah of lithium at 24v. Between 6-7k with the charge controller.

I'd expect 2-3 k for 250-300 ah ( giving 125-150 ah useable) at 12v, and a lot of weight savings and charging speed increase over lead acid. That's a guess on the costs.

Good for a race boat, but pricey....

[wheels 543]

What about the Hamster in a Cage and plenty of Cheese....or whatever a Hamster eats.

[grant 40]

If you need more charging have a look at a alternator strapped to a motor. Similar to your genset and charger but much simpler. Out put is only 12v (13.8 probably) with a generator you are making 240 then reducing it to 12, this simplifies that. Talk to Herdy, he has a handy one, very light, that will pump out about 50 amps.

[wheels 543]

Yes that is a good idea Grant. You can also buy DC gensets. A small motor can power a substantial Alternator. One could also fit a charge controller and that would ramp the Charge current up for bulk charging and do three stage charging. Hmmm, KM, I could make something to suit your needs as an option to consider. Remember that Kipor petrol motor? It runs so sweet and has been very reliable.

[Guest]

Is it not the case with lithium whatevers they not only are lighter for the same amp hours but cycle harder? That is they can be discharged to 80% or so without damage. So less weight and less amp hours needed.

[wheels 543]

What you use you have to replace bbay. Doesn't matter if it is Lead, Lithium or Unobtanium. Ahrs is Ahrs. If you use 100, then you need to replace those 100 and if you keep on taking more that you can replace, eventually the Battery will be Flat. The advantage of Lithium is you can pack the Ahrs back into it much faster.

I am leaving the fact that a Battery not being fully recharged is bad for it, part out of the story for this instance, as KM is only interested in getting across the Big Ditch as fast as he can.

[grant 40]

Yes that is a good idea Grant. You can also buy DC gensets. A small motor can power a substantial Alternator. One could also fit a charge controller and that would ramp the Charge current up for bulk charging and do three stage charging. Hmmm, KM, I could make something to suit your needs as an option to consider. Remember that Kipor petrol motor? It runs so sweet and has been very reliable.

 

That's it, if you want to buy one ready to work it's from oz. comes with reg and ready to go,

[Guest]

no there's also the advantage that it can be discharged further without penalty which means you need less amp hours because with lead acid you need twice the amp hours you use and with lithium you only need a bit more capacity than what you normally use. That plus the less weight for a given amount of amp hours is a deal.

Here's one on trademe......http://www.trademe.co.nz/business-farmi ... 991935.htm

 

200 amp hours and 23.5kg.

[Island Time 1,235]

How deep to discharge has to be a considered point. Yes, a lifepo4 can be discharged, even down to 100%, but most recommend no more than 80%. Makes sense in a race boat, as bbay said, to enable a smaller, lighter batt bank. However;

Depth of discharge (DOD)

All battery manufacturers recommend to keep the Depth of Discharge (DOD) bellow the maximal limit of 100%. Ideally 80% DOD or less is recommended. The rule is quite simple: the smaller DOD the larger number of cycles. With 50% DOD the LiFePO4 cells may have well above 5000 cycles. However it is imporatnt to keep the DOD at the cetral part of the capacity range. If the DOD is not in the center of the capacity range, the cell performace may degrade faster.

As a matter of fact, since it is better to avoid deep cycle discharging, it seems to be better to charge as frequently as possible. It is better to “charge (to full) and use” rather than “use and charge (from null)”.

[Guest]

Sure the lithiums will probably last 6 times the lead acid life at 70% discharge against 50% in the lead.

[Island Time 1,235]

Agreed bbay, but a purchaser should still understand it before deciding how it best suits them to use the batts...

[too_tall 15]

KM, is it feasible to add more solar generation? Maybe the stitch on type if you have room for something like that. Simply put, its not how much storage you have, but what your able to put in per day vrs what you use. Its the most simple system with virtually no weight attached. It has its drawbacks, but if you could get 100ah per day on average, that should comfortably keep you charged during most situations, and the little generator into a smart charger would keep you going when its not such brilliant solar weather or as a booster if you just were not quite getting enough solar. You may have to run it a couple of times a week for an hour or so to push an additional 100 or so amp hours of charge into the battery.

 

Dont deep cycle batteries. None of them like it...

[Zozza 293]

no there's also the advantage that it can be discharged further without penalty which means you need less amp hours because with lead acid you need twice the amp hours you use and with lithium you only need a bit more capacity than what you normally use. That plus the less weight for a given amount of amp hours is a deal.

Here's one on trademe......http://www.trademe.co.nz/business-farmi ... 991935.htm

 

200 amp hours and 23.5kg.

 

Is there an 'Idiots Guide' to Lithium marine batteries?

 

I was going to start with two lead-acid Trojan T-105, 6v Golf Cart Batteries, have them installed in series, and with a two 40 Watt Solar panels each with their own Genasun regulator.

 

Is this enough for weekend and holiday cruising around NZ just to charge things like Ipads, Laptop, and LED lights. No fridge, freezer or any of that amp eating stuff. Real basic power requirements.

 

Now I read about these Lithiums, and while they are expensive (but not ridiculously so), geez they seem almost too good to be true with their light weight and other features.

It seems they might be worth a serious look when I go on more extensive cruising / voyaging in the future.

[Guest]

Hi Partisan, the lithiums are the battery the car mob like to use for electric vehicles and in that use they are cycled very hard. Seems they last well and are good value.

Glad you made that "SIMPLE" motorbike!!

[Guest]

All good stuff.

 

I like those lifepo things and the lithium. Not for the budget concious but if you look at the 'lifetime cost' it's yet another item where the more pricey to buy works out to be the cheapest over it's lifetime, something more need to look at as it'll save them coin.

 

I'm going to splurge and get a good one/two as it just makes sense knot to skimp in this area.

 

KM, is it feasible to add more solar generation?

Yeap easily but why, I don't need it. I know what you mean but I reckon if I was real tight on consumption I could cross the Tassie using no more than 100amps in total. The only concern about capacity I have is the autodriver, if it's working hard it can be a little hungry hence the little genny I'll take. If that autodriver is just cruising, as it usually is, I'm 99% good to go without it. I can live and be ColReg legal on less than 5 amps a day if all hell broke loose.

 

Another reason to take the genny is it gives me 240v if I'm in need of some mid ocean power tool action and/or a power burst for whatever reason. Yeah OK, I need it as I do enjoy a few tunes and the stereo is the the only thing that hasn't been tuned to minimums, in fact it's been tuned for maximums

[Steve Pope 243]

Partisan, We use 4 T105's house batteries and 1 x 12v lead acid starting battery, Charged by 50amp alternator via splitter diode and 75watt solar panel. We don't have refrigeration, electric windlass etc. do have SSB, VHF, Radar, GPS, lap top etc etc. did have incandesant nav lights, (now they have led bulbs) and fluorescent interior lights. We never ran the motor just to charge the batteries.

We went 4 months NZ,Tonga, Fiji, NZ keeping the batteries full was never an issue.