simmering batteries for breakfast

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simmering batteries for breakfast

BFratto
So, my 26 T-125's were subjected to some torture the past few days.

The normally automatic Zivan which would red,yellow,green mode the
batteries has not been reaching yellow or green mode.

The past few days it won't leave red mode because it can't get the voltage
high enough 200-205. (reason? cold weather or bad batteries?)
resulting in torturing the batteries at 174 volts or 183 volts at around 12
Amps long past a full battery. depending on the temperature
This morning the batteries were quite damp on top and opening the covers
shows good gassing going on.
no dry plates yet though thankfully

History: Starting about a month ago, it had some difficulty in yellow mode.

I have had no voltage sag problem with driving 20-30 miles. The batteries
are behaving fairly normally.  I haven't tried to reach my max 50-60 miles.

as far as balancing between batteries, at 183 volts, the range seems to be
6 batteries at ~ 7 volts
10 batteres at ~ 7.1 volts
10 batteries at ~ 7.2 volts

Should I be blaming Zivan for not attaining the max voltage or be
considerring the 2.5 year old batteries to be the culprit?


any other diagnostics to determine what's going on?
i can try my 115 VAC Zivan to see if that can get higher, but I doubt it
will.

Near term solution is to get a 220 Volt AC timer and charge only as long as
needed.


Thanks, Ben

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Re: simmering batteries for breakfast

Roland Wiench
Hello Ben,

I have T-145's and if the battery temperature gets to 60 degrees, then I do
not attempt to charge them to 100% which is 6.37 volts at 1.277 SG after
they rest for about 12 hours.

The normal charge for these type of batteries is 7.4 volts or 192.4 volts at
a battery temperature of 80 degrees F for a pack of 26.

For every drop of 10 degrees below 80 F, then you add 0.028 volts per cell
to the charging volts.  So if the batteries are at 60 F, then that is a 20
degrees drop or 2 x 0.028 = 0.056 charging volts you add per cell or (0.056
x 3 cells) = 0.168 volts per battery.

7.4 + 0.168 = 7.568 per battery or 196.76 V for the pack.

The 202 to 205 volts that you have listed is the equalization charge for
this battery.  I only do this about every 6 months when the batteries are
cooler, so I do not boil them out.

The equalization charge for these batteries are 7.8 V at 80 degree F. So at
this temperature a pack of 26 will be 26 x 7.8 = 208.8 volts.

If the battery temperature is starting out at 60 F then you add the 0.056
volts per cell or 0.168 volts per battery for the 20 degrees drop.  The
charging volts now becomes 26 x (7.8 + 0.168) = 207.1 volts according to the
Trojan manual.

I find its best to only add 0.028 v to the 7.8 for 7.828 volt to each
battery for a equalization charge, because in with one hour of this
charging, the battery will be up to about 75 F.

So at 7.828 V this becomes 203.5 volts for the pack.

The 7.1 to 7.3 is not a bad spread if you are only going to discharge these
batteries only to 50% DOD which is recommended for these type of batteries.
The Trojan manual recommends a equalization charge when the batteries get to
5 percent difference or about 0.35 volts!

I have now been running my batteries now for 6 years and I just got done do
my equalization charge where I had only one battery at a 0.3 volt difference
from one high battery, one at 0.2 volts and all the other are in within 0.1
volts.

You can down load the Trojan Battery Maintenance Manual at:

http://www.trojanbattery.com/customercare_batterymaint9.html

Roland


----- Original Message -----
From: <[hidden email]>
To: <[hidden email]>
Sent: Wednesday, November 28, 2007 10:50 AM
Subject: [EVDL] simmering batteries for breakfast


> So, my 26 T-125's were subjected to some torture the past few days.
>
> The normally automatic Zivan which would red,yellow,green mode the
> batteries has not been reaching yellow or green mode.
>
> The past few days it won't leave red mode because it can't get the voltage
> high enough 200-205. (reason? cold weather or bad batteries?)
> resulting in torturing the batteries at 174 volts or 183 volts at around
> 12
> Amps long past a full battery. depending on the temperature
> This morning the batteries were quite damp on top and opening the covers
> shows good gassing going on.
> no dry plates yet though thankfully
>
> History: Starting about a month ago, it had some difficulty in yellow
> mode.
>
> I have had no voltage sag problem with driving 20-30 miles. The batteries
> are behaving fairly normally.  I haven't tried to reach my max 50-60
> miles.
>
> as far as balancing between batteries, at 183 volts, the range seems to be
> 6 batteries at ~ 7 volts
> 10 batteres at ~ 7.1 volts
> 10 batteries at ~ 7.2 volts
>
> Should I be blaming Zivan for not attaining the max voltage or be
> considerring the 2.5 year old batteries to be the culprit?
>
>
> any other diagnostics to determine what's going on?
> i can try my 115 VAC Zivan to see if that can get higher, but I doubt it
> will.
>
> Near term solution is to get a 220 Volt AC timer and charge only as long
> as
> needed.
>
>
> Thanks, Ben
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

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Re: simmering batteries for breakfast

Richard Acuti
In reply to this post by BFratto

Hi Ben,
 
I would say that it's miles, not years of use that will determine if your batteries are nearing "end of life". Roland is very conservative and manages to milk his batteries for 10 years or more.
 
2.5 years at 10,000 miles/year or more, driving at speeds of 55 mph or higher, and then factor in any hills that make you draw hard amps then yeah, I'd say that maybe your batteries are nearing end of life.
 
I have a Zivan too and I have not experienced the issue that you're having. Temps here have dropped into the mid to low 30F's here in Maryland. Perhaps the ambient temperature combined with the age and state of your batteries has caused this problem. Did the problem coincide with the temperature change?
 
If I were you, I'd consider dropping $45.00 on the Zivan temperature compensation probe. If that doesn't cause a change for the better, you might consider shipping it to a Zivan dealer for a health check. I'm looking at buying one myself.
 
I'm not saying Roland is wrong, he's a wealth of information but the Zivan basically does an equalization charge every single time. The reason it doesn't boil away your batteries is because the final phase is done with a pulsing method that I admittedly don't quite understand. I have 5,000 very hard miles on my batteries as of this month and I've only added water 3 times since the end of February.
I drive my EV like it was stolen. Before Roland, Lee and Dave educated me a little more on golf cart batteries, I was pulling 300 amps from them, generally pounding the crap out of them. They probably shared their information with me in time to prevent any serious damage. Now I only pull 180-200 amps for very short durations but I do routinely drive 55-65 mph. I haven't experienced any loss of performance yet.
 
I appreciate hearing about your experiences since I have the same charger. It'll help prepare me for what might come later.
 
Rich A.
--------------------------------------------------------------------------------------------------------------------------------
 
Message: 32Date: Wed, 28 Nov 2007 12:50:13 -0500From: [hidden email]: [EVDL] simmering batteries for breakfastTo: [hidden email]-ID:<[hidden email]>Content-Type: text/plain; charset=us-ascii So, my 26 T-125's were subjected to some torture the past few days. The normally automatic Zivan which would red,yellow,green mode thebatteries has not been reaching yellow or green mode. The past few days it won't leave red mode because it can't get the voltagehigh enough 200-205. (reason? cold weather or bad batteries?)resulting in torturing the batteries at 174 volts or 183 volts at around 12Amps long past a full battery. depending on the temperatureThis morning the batteries were quite damp on top and opening the coversshows good gassing going on.no dry plates yet though thankfully History: Starting about a month ago, it had some difficulty in yellow mode. I have had no voltage sag problem with driving 20-30 miles. The batteriesare behaving fairly normally. I haven't tried to reach my max 50-60 miles. as far as balancing between batteries, at 183 volts, the range seems to be6 batteries at ~ 7 volts10 batteres at ~ 7.1 volts10 batteries at ~ 7.2 volts Should I be blaming Zivan for not attaining the max voltage or beconsiderring the 2.5 year old batteries to be the culprit?  any other diagnostics to determine what's going on?i can try my 115 VAC Zivan to see if that can get higher, but I doubt itwill. Near term solution is to get a 220 Volt AC timer and charge only as long asneeded.  Thanks, Ben
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