# [EVDL] TS-LFP260 pack capacity test



## EVDL List (Jul 27, 2007)

> -----Original Message-----
> From: [email protected] 
> [mailto:[email protected]] On Behalf Of Willie McKemie
> Sent: May 11, 2009 3:43 PM
> To: Electric Vehicle Discussion List
> Subject: [EVDL] TS-LFP260 pack capacity test
> 
> Or, "Joy in Mudville"
> 
> I've been testing my pack of 45 TS LFP260s in an effort to 
> assure myself that they have the advertised capacity and that 
> I am not nearing the end when I draw down to the presumed 30% 
> or 20% SOC points.
> 
> I've been driving the car, near home, while I fairly closely 
> monitor individual cell voltages. Here are the results for 
> my chosen stopping
> point: 301.0 ah with the static voltage of the lowest cell 
> being 2.91 volts. 45 cell pack static voltage was 140.2. 
> That's actual capacity of 300 ah in 260 ah cells! I'm astonished!

I hate to say it, but if it seems too good to be true... ;^>

Have you verified that your Ah meter is accurate? If it is reading just a little high on the current value, then the Ah values will look larger than they really are. Likewise, if the timebase is a little fast, the meter record more Ah than really are deserved even if the current is accurate.

That said, the fuel guage you are using looks very interesting, especially since Xantrex has now officially discontinued the Link-10!

For the benefit of everyone else, Willie is using this fuel guage: <http://www.ev-power.com.au/-TBS-Electronics-Battery-Fuel-Gauge-.html>.

It looks very much like the Xantrex LinkPRO and LinkLite products: <http://www.xantrex.com/web/id/274/p/1/pt/7/product.asp>; one of these is clearly rebadging the other's product.

Unlike the E-Meter/Link-10, this device does not measure/report kWh, but in all other respects it appears more configurable. The Xantrex site doesn't mention or offer voltage prescalers, but the ev-power site offers both 5:1 and 10:1 prescalers (allowing use up to 350VDC).

Xantrex also only appears to offer an RS232 communications option, but the TBS version offered by ev-power offers a USB interface.

The current sense accuracy is stated to be +/-0.4%, however, there is no accuracy at all stated for the Ah counting.

I would check the configuration for the shunt full-scale current and the shunt full-scale voltage. If the stock shunt is used, the meter should be configured for 500A full-scale and 50mV. I doubt that you have 60mV selected instead of 50mV, but since the full-scale current can be set to arbitrary values, it is possible that an error ere is causing you to see inflated current and Ah values.

Cheers,

Roger.



> 
> Near the end of the test, voltage was obviously dropping, but 
> not alarmingly. A mile or two did not make much difference.
> 
> I think I should re-test every 6 or 12 months, but in the 
> interim, I think I'll declare them to be 300 ah cells and use 
> 210 ah and 260 ah as the 30% and 20% SOC points. That's up 
> from the 180 ah and 210 ah I've been using. That would make 
> my ranges 105+ and 130+ miles.
> 
> While trying to suck maximum amps, I tried the air 
> conditioner. We're getting 90-95 degree days now. I was 
> rather surprised that the AC worked VERY well. I'll probably 
> report later the cost of the AC in watt-hr/mile.
> 
> The car continues to be plagued with very brief power 
> dropouts (and now
> surges) that I've mentioned here before. I am attributing 
> that problem to the Curtis controller and intend to soon try 
> a Logisystem.
> 
> About 4300 miles now:
> http://www.evalbum.com/2314
> 
> --
> Willie, ONWARD! Through the fog!
> http://counter.li.org Linux registered user #228836 since 
> 1995 Debian3.1/GNU/Linux system uptime 513 days 11 hours 15 minutes
> 
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> 
> 

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## EVDL List (Jul 27, 2007)

> Roger Stockton wrote:
> > > I've been driving the car, near home, while I fairly closely
> > > monitor individual cell voltages. Here are the results for
> > > my chosen stopping
> ...


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## EVDL List (Jul 27, 2007)

> Roger Stockton wrote:
> > I hate to say it, but if it seems too good to be true... ;^> Have you
> > verified that your Ah meter is accurate?
> >
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> > Xantrex has the LinkLite and LinkPro made in China by some
> > contractor.
> ...


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## EVDL List (Jul 27, 2007)

> Roger Stockton wrote:
> > The LinkPRO/LinkLite seem to go for US$350/270 respectively; the E-Xpert pro/lite is $359/285 from EV Power, though it isn't clear if those prices are in US$ or A$, though I suspect they are US$.
> 
> I've made several purchases from EV-Power, including two TBS meters.
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> >> Xantrex has the LinkLite and LinkPro made in China by some
> >> contractor.
> 
> ...


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## EVDL List (Jul 27, 2007)

> Willie McKemie wrote:
> 
> > I remain convinced that the capacity is significantly greater
> > than advertised, but maybe "only" 290 or 295 ah.
> ...


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## EVDL List (Jul 27, 2007)

> Roger Stockton wrote:
> > Willie McKemie wrote:
> >
> > > I remain convinced that the capacity is significantly greater
> ...


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## EVDL List (Jul 27, 2007)

Hi Willie,
What BMS are you using with your TS batteries?
I just bought a set of TS-LFP40AHA for my motorcycle & they came with 2 of
these Chargery Power DB8 Digital Balancer units.
They work fine on my littles 40ah cells but I don't think they will work
with the larger TS cells.
Thanks,
Neal

Willie McKemie-3 wrote:
> 
>


> Roger Stockton wrote:
> >> Willie McKemie wrote:
> >>
> >> > I remain convinced that the capacity is significantly greater
> ...


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## EVDL List (Jul 27, 2007)

> shred wrote:
> >
> > Hi Willie,
> > What BMS are you using with your TS batteries?
> ...


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## EVDL List (Jul 27, 2007)

Yes they alarm if a cell is below 2.8 volts or if it is above 4.22.
And they balance each cell within 10 mv but they only have the ability to
drain 300ma per cell to achieve that balance.
They will work on up to 8 cells per balancer. The cost is $50.00 per unit.
I needed 2 for my motorcycle but would need 5 for my car.
He said they would work on the 100 ah cells but I think they are to low
power to work on anything much bigger. So far they are working great on my
40ah cells
Here is a link. 
http://www.chargery.com/DB8.asp
Neal


Willie McKemie-3 wrote:
> 
>


> shred wrote:
> >>
> >> Hi Willie,
> >> What BMS are you using with your TS batteries?
> ...


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## EVDL List (Jul 27, 2007)

I thought 2.8-4.25 was Lithium Cobalt cell voltages and that 3.65 was the upper charge limit for LiFePo4
I know ThunderSky had reccommended higher voltages than othere manufactures and we uese to speculate it was to overcome internal resistance or to bump up ah capacity at the expense of cycle life. 

Any one know for sure?
> Yes they alarm if a cell is below 2.8 volts or if it is above 4.22

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## EVDL List (Jul 27, 2007)

The Evpower BMS that I have (the older version) shunts around 700ma.
These have been effective in 200AH packs (biggest application ive seen
personally).

300ma should be fine for the bigger cells. If you really need more than
that, theres something wrong with your pack.

Matt 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of shred
Sent: Sunday, 17 May 2009 12:43 AM
To: [email protected]
Subject: Re: [EVDL] TS-LFP260 pack capacity test


Yes they alarm if a cell is below 2.8 volts or if it is above 4.22.
And they balance each cell within 10 mv but they only have the ability to
drain 300ma per cell to achieve that balance.
They will work on up to 8 cells per balancer. The cost is $50.00 per unit.
I needed 2 for my motorcycle but would need 5 for my car.
He said they would work on the 100 ah cells but I think they are to low
power to work on anything much bigger. So far they are working great on my
40ah cells
Here is a link. 
http://www.chargery.com/DB8.asp
Neal


Willie McKemie-3 wrote:
> 
>


> shred wrote:
> >>
> >> Hi Willie,
> >> What BMS are you using with your TS batteries?
> ...


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## EVDL List (Jul 27, 2007)

Your right Jeff.
I was reading the LiPo spec for the alarm on the high end.
It's alarm sounds when below 2.8 or above 3.75.
This blancer does both chemistries.
It has a switch on the front.
If you run your charger through it then it will also shut off charging if
high voltage it hit.
But you can only charge up to 8 cells at a time if you run your charger
through it.
So I don't, I just use it for cell balancing.
Neal




> Jeff Shanab wrote:
> >
> > I thought 2.8-4.25 was Lithium Cobalt cell voltages and that 3.65 was the
> > upper charge limit for LiFePo4
> ...


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