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  #1  
Old 15-10-2016, 09:01 PM
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Piranha Piranha is offline
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lithium batteries

Just chasing some feedback from those that are using Lithium batteries for their leccys .
I have a small poly boat and have been running a 105ah agm but can't get a full day fishing in the flow of the murray, I looked at 150ah agm but their a bit big and well over 40kg compared to lithium 14kg which has 25% more power.

I know obviously the prices are huge but so are the stated lifespans so I'm keen to hear from those that run them.

Cheers
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Old 16-10-2016, 05:34 AM
beans07 beans07 is offline
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I have extensive experience with using them in RC models which demand high Amp draw until they are fully drained which is usually down to 20% of remaining capacity.

The problem with lithium for this application is the cost. As they become main stream in the deep cycle type applications the price will change. The problem we have had in the model world is not all brands are created equally and the actual claims they make as far as capacity, amp draw etc.. are not very reliable. I have had much more success in the more expensive and better known brands than cheapies. There isn't that many cell manufacturers but there are a lot of brands that assemble those cells.

With this in mind I would pick a reputable brand and a decent warranty. If you drop a cell (usually happens early on and usually to do with the quality of how the cells were put together and matched together) you want to have the back up support as you are outlaying a huge cost to begin with.

The best part is the usable capacity is far greater than an AGM or Wet Cell battery. Lithium is anywhere down to 20% of full capacity (using 80% of capacity). They have a very different discharge curve which will drop from full voltage of 3.6v per cell (14.4v) down to a nominal 3.3v per cell (13.2) very quickly, it will sit there for a long time and may vary down to 12.2v or so then all of a sudden drop to 10.8v or so which is around that 20%.

There are quite a lot of different compositions of lithium batteries. LiFeP04 (Lithium Phosphate) is the most suitable for deep cycles. Can be kept fully charged, can be charged fast and can be cycled many times. Also over discharging generally doesn't hurt them so much, it will deplete lifespan a little but not a lot to be concerned about.

So a 100AH Lithium you could get 70% (on the safe side) out of so 70AH and 100AH AGM you could get a max of 50AH. Thus a lot more usable capacity. Lithium holds better under load so in theory you could get considerately more time out of one over a an AGM or Wet Cell.

I am not sure how they are set up but some most likely have a built in charging circuit so that a normal charger could be used whilst others probably need a special charger. That would be battery/brand dependant.

Personally if I was to change out a batter a Lithium is the only way. only the cost consideration really.
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Old 16-10-2016, 05:26 PM
bjspinner bjspinner is offline
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Best place I found was in this link.

http://www.ev-power.com.au/-EV-Power...atteries-.html

I have one in my kayak 20amp version, best to run the balance system for charging as unbalanced cells are you main problem to cell damage which can be costly.
As the previous poster beans said the main advantages are the discharge capacity compared top lead acid batteries and weight of the cells.
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Old 17-10-2016, 12:04 AM
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Thanks for that info Beans and Bjspinner.

Beans the brand im looking at is a SENTRY LiFPO4. I can get one at cost price around $1400 and around $400 for a special charger.
Most of the battery brands I'm familiar with don't do lithium so I'm hoping the above is a good brand?

Thanks again for all that info mate, It's interesting how much extra energy they can store as thats exactly what I need and the lack of weight is a big bonus. With the long lifespan they should save me money in the long run.

Last edited by Piranha; 17-10-2016 at 12:20 AM.
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Old 17-10-2016, 12:10 AM
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Thanks for the link BJ , those are my second option that I checked out and are considerably cheaper $800 for 100ah.
Good to hear that yours is a good battery
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  #6  
Old 17-10-2016, 03:45 AM
t303 t303 is offline
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I am using a 60ah LiFePO4 to run the fridge in the back of the 4WD. Don't go spending a fortune on a charger, just get a good one (I use Projecta IC series) that gives you a proper AGM setting, ideally about 14.1 to 14.4V max. These batteries don't need a boost phase, ideally you charge at constant V, which means you can charge (even to full) using the alternator on your car (check it's output V though). If you stay away from the limits of the pack voltages (usually about 14.6V max) you run less risk of cooking a cell if they drift out of balance. You will only lose a few percent capacity, but it's safer in the long run. You need to be careful to avoid over discharge lest a cell get reverse charged from the rest of the battery. The other magic about these cells is that they have near zero internal resistance at any state of charge, so if you can feed it the amps it can take it; hence why the car alt is such a great way to do it.
cheers
Steve
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Old 17-10-2016, 04:08 AM
beans07 beans07 is offline
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Quote:
Originally Posted by bjspinner View Post
Best place I found was in this link.

http://www.ev-power.com.au/-EV-Power...atteries-.html

I have one in my kayak 20amp version, best to run the balance system for charging as unbalanced cells are you main problem to cell damage which can be costly.
As the previous poster beans said the main advantages are the discharge capacity compared top lead acid batteries and weight of the cells.

Correct. If cells aren't balanced to each other that's when issues can arise. The cells are 4 cell banks that are wired in series (also may be many cells wired in parallel as well to get then those banks, which then will be wired in series to get the AH required.) I haven't looked too much into the Car battery sized lithium batteries to see how they are wired and constructed as of yet.

Cells (or cell banks) may draw down slightly differently depending on the internal resistance of each cell). Lower the internal resistance the better the cell is. Internal resistance is a very good indicator of the quality of the battery.

The problem if they aren't balanced is that one cell may be at 2.8v (nearly flat and another is at 3.3v (nominal voltage), as the battery is wired as a 12v battery the application (electric motor in this case) will just pull them all down the same. Thus you may have one cell drawn way bellow it's allowed level and one (or multiple cells) a lot higher. This damages batteries. The other main issue is overcharging. Lithium batteries do not like to be overcharged, fires can happen (yes I have had fires). A balance charger effectively charges all cells at once, firstly with constant current then constant voltage. Constant current takes them to 90% then constant voltage does the last 10%, inside this last 10% the balance part brings down the higher voltage cells to the lowest voltage cell, never allowing them to go over the maximum allowed voltage. With this in mind it takes a lot longer for the last 10% of charging than the first part to 90%. Yes you can pull the charger off at this 90% but run the risk of what I mentioned above.

The manufacturers are ripping people blind with making people buy a $400 charger. My hobby chargers have considerably more features and less cost. Internal resistance measuring, full logging, via computer, I can completely configure balancing rates, charging rates, many different types of batteries, lithium of various types, AGM, wet cell, nicd, nimh etc.. I can set the float points of AGM's etc,, I can charge at full 40AMPS, I can charge from 1.2v up to 50v batteries. Many many other things for about $200.

Any way I am getting far too side tracked LOL.

Good luck with it all, I am sure it will work out much more beneficial in the long run.
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Old 17-10-2016, 04:34 PM
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Thanks for all the extra info guys much appreciated.

The charger price was just an estimate by my mate at the battery supplier, I'll get that for cost price too so hopefully it won't be quite that expensive. I think he was giving me a worst possible senario number.
I have a projecta 7 stage smart charger so I'll look into if that will work first ☺
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Old 17-10-2016, 09:06 PM
t303 t303 is offline
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Quote:
Originally Posted by Piranha View Post
Thanks for all the extra info guys much appreciated.

The charger price was just an estimate by my mate at the battery supplier, I'll get that for cost price too so hopefully it won't be quite that expensive. I think he was giving me a worst possible senario number.
I have a projecta 7 stage smart charger so I'll look into if that will work first ☺
That is what I use, it will be perfectly adequate, better if it is 25 or 35A as the battery will accept all you can give it.
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Old 17-10-2016, 09:16 PM
bjspinner bjspinner is offline
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The beauty of these cells is you can also lay them on their side so you can configure the cells to suit an available area.

I really like these in this link as BMS systems bolt on to manage individual cells

http://www.ev-power.com.au/-CALB-Lit...O4-Cells-.html
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Old 17-10-2016, 09:52 PM
t303 t303 is offline
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Quote:
Originally Posted by bjspinner View Post
The beauty of these cells is you can also lay them on their side so you can configure the cells to suit an available area.

I really like these in this link as BMS systems bolt on to manage individual cells

http://www.ev-power.com.au/-CALB-Lit...O4-Cells-.html
Hey Chaps
Over the last two years I have been running the fridge on the Liths, I have not seen the cells get more than a few mV out of balance when checked VERY occasionally, and I have not once bothered to do a manual balance. From what I have read most of the cell level BMS systems seem to work by bleeding off the high cells (usually just through a resistive circuit) to balance the battery. Problem is that it only works while the battery is resting or in light use, if you are putting 35A through the battery on charge the BMS won't be able to bleed enough off (imagine how hot a resistor gets dissipating that excess current). Clever ones actually cut off the charge, but they are somewhat $$$$! The other problem that has occurred is that the BMS board has faulted, discharged and %*$#@ed the cell (it is an electronic device after all).
IMHO, KISS! Fit a low voltage alarm or cutoff (I use a Baintech programmed to 11.5V, when battery is unloaded rebounds to about 11.8V: https://www.baintech.com.au/business...-cutout-12-24v ) and use the AGM setting on your Projecta charger. Then sit back and relax, you won't have to be constantly checking that you aren't cooking or over discharging the battery.
You will lose far less than 10% of the capacity using these parameters, but won't have to exist in a state of high anxiety.
cheers
Steve
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Old 17-10-2016, 10:51 PM
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I'm going into information overload lol ☺

My charger is only 8 amp so I'll look to upgrade to something that can put a bit more in.
I'm thinking about going for a 120ah lithium now and run leccy, sounder, bilge and lights all off the one battery..just hope I don't get interference on the sounder as some people do.

Those bolt on's look good BJ but unfortunately are the wrong shape for my little rig.
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Old 28-11-2016, 12:59 AM
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I've ended up installing a Sentry lithium 100ah with an Enerdrive 3 bank 20amp charger. A bit pricey coming in just under 2k for the pair but should be worth it in the long run.
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