Batteries and New Battery Technologies

BertKu, that link has an error or something I get "failed to connect" issues No way, I have spiral wound AGM's that supply 220Ah and weigh less than that - I said nothing of KWh I need to be able to supply high wattage for the drive motors - many batteries cannot handle that and keep a long life... or accept high charge rates... (8 x 20kg gives me 110 Ah and 48 volt nominal system which is paralleled to offer 220 Ah @ 48 volts from less than 320kg using lead-acid technology...

Google - Optima D34M for their specifications sheet...

 

Hi Masalai,

Sorry for that. Please go to www.altairnano.com , click on solutions and click on 50Ah battery.

I learned the hard way with the lead acid batteries I am using for the timers we are making. By exceeding the nomial current 1C at which the AmpereHour the battery is normally given, it reduces the Amperehour of the battery. i.e. in your case you draw 150 Ampere to give you 7000 watt, your 110 Amperhour battery may only be 80 Amperehour with maybe 400 deepcharging cycles. The manufacturer can supply more details to you.

This altairnano battery can at 25 degrees handle at 1C , 48 Volt , 12000 deepcharging cycles and at 500 Ampere (24000 watts) still basically 50 Amperehour per cell.

If you deepcharge every day your lead acid battery, it would be more economical to look at an altairnano type of battery, to avoid replacing the batteries every 2 years at great cost.

It is a matter of calculating the projected life time of the batteries used.

I fully agree with a previous comment , that it would be high time that governments should be pumping vast sums of money into new battery technologies.

BertKu

 

Hi Masalai, I am confused. The specs of the Optima D34M states 55Amperehour, while you state 110Amperehour. Do you use a different Optima model??

BertKu

 

I still get a failed to connect, and nothing else seems to help? is it ALTAIRNANO all in lower case? no underscore/hyphens/dots etc, - Most curious?

 

4 banks of 4 batteries in series/parallel connection - 16 batteries, 48v and 220 Ah... 20kg each, I can lift to replace / service etc best compromise at present... They will not be fully discharged, less than 50%, probably as little as 40% before genset charging, 2000 watt solar panels will provide trickle / daytime top-up / boost... I will also have a total of 220 Ah of 12V battery power for ships services / nav / engine start...

 

When comparing different styles of batteries you need to make certain the comparisons align.

Lead Acid batteries are given current-time rating at the 20 hour rate. The Altair batteries are quoted at the 1 hour rate.

So a 220Ah VRLA battery will give 220Ah if the drain is 11A. If it is discharged at 50A the available capacity will be around 160Ah. The energy density at the 50A rate is therefore 160Ah x 48V / 320kg = 24Wh/kg - likely a little less due to voltage droop.

If you had 20 Altair cells the energy density is 50Ah x 46V / 32kg = 72Wh/kg. Voltage droop is usually not as bad with the lithium batteries.

If you want to pull 50A for about 1 hour then you only need 32kg of Altair batteries. If you want to pull 50A for 3 hours, equivalent to the 220Ah VRLA, then you need 60 cells or 96kg. I expect these would be very expensive.

However if weight is the driving factor then the Altair batteries are 3 times better than the VRLA for energy density at what will be an expected current drain while powering.

If anyone can get a price for the Altair cells I will be interested to know.

Rick W

 

I am sure I had some other "discharge rates" down to C5, for the spiral wound... Here is one brochure, so I could be confused about the C5 rate... So what do the "Performance Data" and "Power" mean, the prime objective, is to run 2 Torqeedo 4.0R for less than 20 minutes without genset support to get under way and clear the overnight anchorage. Average burn about 2000W or less...

May be used whilst sailing to add a bit of "zest" at around 1000 to 2000 watts each engine, supported by solar-panels (when the batteries are full) - - When anchored up, batteries will supply galley / domestic services with genset to keep charge above say 50% - which I am told will extend use-able lifespan...

What is your assessment? I would rather not go much heavier than these batteries and their cost is at my upper limit... I see no point in only being able to charge at 50A (2400 watts) when genset will push briefly 6000+ watts and better than 4000 continuous...

 

The data sheet rates the battery at 55Ah at the 20 hour rate. If you only want to run the torqeedos at a combined 2000W for 15 to 30 minutes then 20 Altair cells would do the job as well as the 16 Optima batteries. The Altair would be 1/10th the weight.

You will probably find the 20 Altair cells are a similar cost to the 16 Optima if you can actually get them. The main advantage is the weight saving.

On the downside the actual storage capacity is less if you only get 20 cells.

I am not rushing into lithium batteries other than the little one I am playing with. AND it frightens me. I have already burnt up a set of charging leads in a split second when I accidently shorted them. For something that weighs less than 1kg it has huge power density.

The Optima batteries should give acceptable life under proposed use.

Rick

 

Thanks very much Rick... "You must spread some Reputation around before giving it to Rick Willoughby again"

 

Altairnano

Hi Masalai, If you e-mail your e-mail addres to gqrsoftware@isat.co.za I will attach the pdf file to an e-mail to you. This Altair battery can be charged even at a 300 Ampere rate. Thus your generator will be able to do the the job fast. All curves are attached to this pdf file. Rick has nicely given you all the other advise you need.

Hi Rick,

Nice to see you back again. I was playing with my little rubber duck on a local lake. Just to play around with different concepts. At one stage I was blown back by the wind instead of making progress. I still enjoy your video's and learn a lot from them. Next time I will try a screw like a corkscrew and see what that gives me for results.

BertKu

 

PDF file

Hi Masalia, For your convienence I have attched the pdf file hereby.

BertKu

 

Hi Masalai,

The only drawback if you do use the lithium batteries is, that you need some form of management electronics not to exceed the voltage levels per cell. In your case if you would use 20 cells is the maximum voltage per cell i.e. at 2.8 / 2.9 Volt during charging and the minimum voltage of 1,5 / 2 Volt depending on the ambient temperature and when your battery is "flat".

But Rick will have enough experience by now to help you out with some tips
(Rick, I hope not that you mind to pass the buck)

BertKu

 

BertKu, thanks for the info, I think I will wait for that technology to mature a bit first...

 

It is a pleasure. One is never to old to learn, but also on the other hand never to young to start experimenting. If I was you , I would investigate what is needed to charge those 20 Lithium batteries properly. As soon the Super Cap project is of my desk, I may start to make a 20 cell Lithium battery management. Make the PC board and program a Microchip. The answers on the questions I have, is to figure out is how to limit the voltage per cell, during charging . A possiblity could be to have 20 relays. If one of the 20 cells are reaching the 2.8 Volt level (at that ambient temperature) then to load this cell with a resistor. If the battery becomes empty, in that case, as soon a cell is below the 1,5 Volt, I just switch the alarm on and if the right action is not taken, than to disconnect the charger. But at present I have my hands full with other projects. Put an Australian call through to Rick. I have full confidence in him that he can help you. Sorry guys you lost with rugby here. Next time better.

BertKu

 

Anyone know what happens upon an individual cell reversal with Li systems? Does the whole pack shut down before that happens with the BMS? Do you get a dangerous fire or explosion if the BMS fails? In other battery chemistries, a reversed cell continues to conduct and is eventually ruined, but the battery continues to operate safely, at a reduced power level.

Porta