# [EVDL] AGM battery health



## EVDL List (Jul 27, 2007)

> Todd [email protected] wrote:
> > What is the best method of checking an AGM battery's health?
> 
> The best method is a load test. Fully charge it, then connect a load
> ...


----------



## EVDL List (Jul 27, 2007)

Thanks for responding Lee.
The batteries are a 200 AH/ 6 volt, 216 volt string. 
Fully charged pack is 236 volts after resting overnight, which is 6.55
volts per battery.
I checked all the batteries voltages, the low was 6.33v and the high was
6.60v, most were around 6.5v.
When the pack was new, I would get 55 miles per charge.
I have put 2800 miles on them. Most trips about 35 miles.
Over a months time it went down to about 10-14 miles per charge.
I use a Zivan charger with CC-CV and a pulse finish ( AGM algorithm)
I am in Phoenix, the night time temps. are in the 40's. Day temps. in
the 70's.
Thanks, Todd.

-------- Original Message --------
Subject: Re: [EVDL] AGM battery health
From: Lee Hart <[email protected]>
Date: Sun, February 01, 2009 7:39 am
To: Electric Vehicle Discussion List <[email protected]>



> Todd [email protected] wrote:
> > What is the best method of checking an AGM battery's health?
> 
> The best method is a load test. Fully charge it, then connect a load
> ...


----------



## EVDL List (Jul 27, 2007)

200Ah x 216V = 43kWh nominal, at least 22 kWh usable
without murdering them.
55 miles range means over 400Wh per mile, which is on
the high side.

Either you have a lead foot and many traffic lights
or a very heavy vehicle or it is not tuned to its
optimal performance else you would get more range. 

If you can tell more about the finishing voltage
and duration of the Zivan as well as whether you
park inside or outside in the 40 deg weather, so
we can guesstimate the battery temp....

BTW, it only takes a few too deep discharges or
an unbalanced cell or two to really destroy your
range.

Do you have AGM 6V battery? That is not common...
Which ones are they - not all brands and types
are equal.
Most 6V are flooded (Golf Cart) batteries.

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of [email protected]
Sent: Monday, February 02, 2009 9:54 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] AGM battery health

Thanks for responding Lee.
The batteries are a 200 AH/ 6 volt, 216 volt string. 
Fully charged pack is 236 volts after resting overnight, which is 6.55
volts per battery.
I checked all the batteries voltages, the low was 6.33v and the high was
6.60v, most were around 6.5v.
When the pack was new, I would get 55 miles per charge.
I have put 2800 miles on them. Most trips about 35 miles.
Over a months time it went down to about 10-14 miles per charge.
I use a Zivan charger with CC-CV and a pulse finish ( AGM algorithm)
I am in Phoenix, the night time temps. are in the 40's. Day temps. in
the 70's.
Thanks, Todd.

-------- Original Message --------
Subject: Re: [EVDL] AGM battery health
From: Lee Hart <[email protected]>
Date: Sun, February 01, 2009 7:39 am
To: Electric Vehicle Discussion List <[email protected]>



> Todd [email protected] wrote:
> > What is the best method of checking an AGM battery's health?
> 
> The best method is a load test. Fully charge it, then connect a load
> ...


----------



## EVDL List (Jul 27, 2007)

> Cor van de Water wrote:
> >
> > Either you have a lead foot and many traffic lights
> > or a very heavy vehicle or it is not tuned to its
> ...


----------



## EVDL List (Jul 27, 2007)

It is a heavy vehicle, the Conceptor G-Van.

The charging characteristics are:
T1 (max 10hr)CC-until 257.4V
T2 (max 3hr)CA-until 7.8A
T3 (max 6hr)pulse current @7.8A
The van is parked in a unheated garage,probably 50-55 degrees.

They are 6 volt AGM's, Centennial CBM83CHP06V27.

Todd.

-------- Original Message --------
Subject: Re: [EVDL] AGM battery health
From: "Cor van de Water" <[email protected]>
Date: Mon, February 02, 2009 1:29 pm
To: "Electric Vehicle Discussion List" <[email protected]>

200Ah x 216V = 43kWh nominal, at least 22 kWh usable
without murdering them.
55 miles range means over 400Wh per mile, which is on
the high side.

Either you have a lead foot and many traffic lights
or a very heavy vehicle or it is not tuned to its
optimal performance else you would get more range. 

If you can tell more about the finishing voltage
and duration of the Zivan as well as whether you
park inside or outside in the 40 deg weather, so
we can guesstimate the battery temp....

BTW, it only takes a few too deep discharges or
an unbalanced cell or two to really destroy your
range.

Do you have AGM 6V battery? That is not common...
Which ones are they - not all brands and types
are equal.
Most 6V are flooded (Golf Cart) batteries.

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of [email protected]
Sent: Monday, February 02, 2009 9:54 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] AGM battery health

Thanks for responding Lee.
The batteries are a 200 AH/ 6 volt, 216 volt string. 
Fully charged pack is 236 volts after resting overnight, which is 6.55
volts per battery.
I checked all the batteries voltages, the low was 6.33v and the high was
6.60v, most were around 6.5v.
When the pack was new, I would get 55 miles per charge.
I have put 2800 miles on them. Most trips about 35 miles.
Over a months time it went down to about 10-14 miles per charge.
I use a Zivan charger with CC-CV and a pulse finish ( AGM algorithm)
I am in Phoenix, the night time temps. are in the 40's. Day temps. in
the 70's.
Thanks, Todd.

-------- Original Message --------
Subject: Re: [EVDL] AGM battery health
From: Lee Hart <[email protected]>
Date: Sun, February 01, 2009 7:39 am
To: Electric Vehicle Discussion List <[email protected]>



> Todd [email protected] wrote:
> > What is the best method of checking an AGM battery's health?
> 
> The best method is a load test. Fully charge it, then connect a load
> ...


----------



## EVDL List (Jul 27, 2007)

216V = 108 cells
257.4 /108 = 2.38V per cell, sounds like it is in the ballpark.
How much current during "CC" charging?

How do you balance the battery pack?
Having a few cells out of whack and
either you reverse them a few times
and they are toast (lay your hand on
each battery after a few miles drive.
You will *feel* the increased temp of
a weak cell that has been reversed and 
now acts as a large resistor instead
of a battery.

The other possibility is cells that are
higher in charge than others.
You hit them up with max charge current,
likely in the 20-30A range and you boil
them to death, drying them out.
They will have lower and lower capacity
the drier they get.
This type of problem is only found with
a load test. The battery is unusually
strong, almost no sag under load, but
it drops as a rock as soon as the dry
cell has spent its capacity.

If you do not balance, it is easy for 
one or a few cells to hit 2.7V while
you won't see it in the total 200+V
of the long string you have.
I had 312V in 26 x 12V AGMs and had no
clue that the cells in the batteries 
were so far apart until I started 
hurting them.

Regards,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of [email protected]
Sent: Tuesday, February 03, 2009 10:23 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] AGM battery health

It is a heavy vehicle, the Conceptor G-Van.

The charging characteristics are:
T1 (max 10hr)CC-until 257.4V
T2 (max 3hr)CA-until 7.8A
T3 (max 6hr)pulse current @7.8A
The van is parked in a unheated garage,probably 50-55 degrees.

They are 6 volt AGM's, Centennial CBM83CHP06V27.

Todd.

-------- Original Message --------
Subject: Re: [EVDL] AGM battery health
From: "Cor van de Water" <[email protected]>
Date: Mon, February 02, 2009 1:29 pm
To: "Electric Vehicle Discussion List" <[email protected]>

200Ah x 216V = 43kWh nominal, at least 22 kWh usable
without murdering them.
55 miles range means over 400Wh per mile, which is on
the high side.

Either you have a lead foot and many traffic lights
or a very heavy vehicle or it is not tuned to its
optimal performance else you would get more range. 

If you can tell more about the finishing voltage
and duration of the Zivan as well as whether you
park inside or outside in the 40 deg weather, so
we can guesstimate the battery temp....

BTW, it only takes a few too deep discharges or
an unbalanced cell or two to really destroy your
range.

Do you have AGM 6V battery? That is not common...
Which ones are they - not all brands and types
are equal.
Most 6V are flooded (Golf Cart) batteries.

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of [email protected]
Sent: Monday, February 02, 2009 9:54 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] AGM battery health

Thanks for responding Lee.
The batteries are a 200 AH/ 6 volt, 216 volt string. 
Fully charged pack is 236 volts after resting overnight, which is 6.55
volts per battery.
I checked all the batteries voltages, the low was 6.33v and the high was
6.60v, most were around 6.5v.
When the pack was new, I would get 55 miles per charge.
I have put 2800 miles on them. Most trips about 35 miles.
Over a months time it went down to about 10-14 miles per charge.
I use a Zivan charger with CC-CV and a pulse finish ( AGM algorithm)
I am in Phoenix, the night time temps. are in the 40's. Day temps. in
the 70's.
Thanks, Todd.

-------- Original Message --------
Subject: Re: [EVDL] AGM battery health
From: Lee Hart <[email protected]>
Date: Sun, February 01, 2009 7:39 am
To: Electric Vehicle Discussion List <[email protected]>



> Todd [email protected] wrote:
> > What is the best method of checking an AGM battery's health?
> 
> The best method is a load test. Fully charge it, then connect a load
> ...


----------



## EVDL List (Jul 27, 2007)

CC is 17.5A.
I have not balanced them. Through ignorance, I assumed that a good
charger and temp probe
would be all that is needed.
I am used to flooded cells, where they kind of take care of that
themselves.
What do you recommend?
It seems that load testing the best way to figure this out.

Todd.

-------- Original Message --------
Subject: Re: [EVDL] AGM battery health
From: "Cor van de Water" <[email protected]>
Date: Tue, February 03, 2009 10:26 am
To: "Electric Vehicle Discussion List" <[email protected]>

216V = 108 cells
257.4 /108 = 2.38V per cell, sounds like it is in the ballpark.
How much current during "CC" charging?

How do you balance the battery pack?
Having a few cells out of whack and
either you reverse them a few times
and they are toast (lay your hand on
each battery after a few miles drive.
You will *feel* the increased temp of
a weak cell that has been reversed and 
now acts as a large resistor instead
of a battery.

The other possibility is cells that are
higher in charge than others.
You hit them up with max charge current,
likely in the 20-30A range and you boil
them to death, drying them out.
They will have lower and lower capacity
the drier they get.
This type of problem is only found with
a load test. The battery is unusually
strong, almost no sag under load, but
it drops as a rock as soon as the dry
cell has spent its capacity.

If you do not balance, it is easy for 
one or a few cells to hit 2.7V while
you won't see it in the total 200+V
of the long string you have.
I had 312V in 26 x 12V AGMs and had no
clue that the cells in the batteries 
were so far apart until I started 
hurting them.

Regards,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of [email protected]
Sent: Tuesday, February 03, 2009 10:23 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] AGM battery health

It is a heavy vehicle, the Conceptor G-Van.

The charging characteristics are:
T1 (max 10hr)CC-until 257.4V
T2 (max 3hr)CA-until 7.8A
T3 (max 6hr)pulse current @7.8A
The van is parked in a unheated garage,probably 50-55 degrees.

They are 6 volt AGM's, Centennial CBM83CHP06V27.

Todd.

-------- Original Message --------
Subject: Re: [EVDL] AGM battery health
From: "Cor van de Water" <[email protected]>
Date: Mon, February 02, 2009 1:29 pm
To: "Electric Vehicle Discussion List" <[email protected]>

200Ah x 216V = 43kWh nominal, at least 22 kWh usable
without murdering them.
55 miles range means over 400Wh per mile, which is on
the high side.

Either you have a lead foot and many traffic lights
or a very heavy vehicle or it is not tuned to its
optimal performance else you would get more range. 

If you can tell more about the finishing voltage
and duration of the Zivan as well as whether you
park inside or outside in the 40 deg weather, so
we can guesstimate the battery temp....

BTW, it only takes a few too deep discharges or
an unbalanced cell or two to really destroy your
range.

Do you have AGM 6V battery? That is not common...
Which ones are they - not all brands and types
are equal.
Most 6V are flooded (Golf Cart) batteries.

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of [email protected]
Sent: Monday, February 02, 2009 9:54 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] AGM battery health

Thanks for responding Lee.
The batteries are a 200 AH/ 6 volt, 216 volt string. 
Fully charged pack is 236 volts after resting overnight, which is 6.55
volts per battery.
I checked all the batteries voltages, the low was 6.33v and the high was
6.60v, most were around 6.5v.
When the pack was new, I would get 55 miles per charge.
I have put 2800 miles on them. Most trips about 35 miles.
Over a months time it went down to about 10-14 miles per charge.
I use a Zivan charger with CC-CV and a pulse finish ( AGM algorithm)
I am in Phoenix, the night time temps. are in the 40's. Day temps. in
the 70's.
Thanks, Todd.

-------- Original Message --------
Subject: Re: [EVDL] AGM battery health
From: Lee Hart <[email protected]>
Date: Sun, February 01, 2009 7:39 am
To: Electric Vehicle Discussion List <[email protected]>



> Todd [email protected] wrote:
> > What is the best method of checking an AGM battery's health?
> 
> The best method is a load test. Fully charge it, then connect a load
> ...


----------



## EVDL List (Jul 27, 2007)

In future - at minimum zener regs on sealed batts.
For your pack (also to see which ones are good/bad,
you need to do a load test.

Success,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of [email protected]
Sent: Wednesday, February 04, 2009 12:50 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] AGM battery health

CC is 17.5A.
I have not balanced them. Through ignorance, I assumed that a good
charger and temp probe
would be all that is needed.
I am used to flooded cells, where they kind of take care of that
themselves.
What do you recommend?
It seems that load testing the best way to figure this out.

Todd.

-------- Original Message --------
Subject: Re: [EVDL] AGM battery health
From: "Cor van de Water" <[email protected]>
Date: Tue, February 03, 2009 10:26 am
To: "Electric Vehicle Discussion List" <[email protected]>

216V = 108 cells
257.4 /108 = 2.38V per cell, sounds like it is in the ballpark.
How much current during "CC" charging?

How do you balance the battery pack?
Having a few cells out of whack and
either you reverse them a few times
and they are toast (lay your hand on
each battery after a few miles drive.
You will *feel* the increased temp of
a weak cell that has been reversed and 
now acts as a large resistor instead
of a battery.

The other possibility is cells that are
higher in charge than others.
You hit them up with max charge current,
likely in the 20-30A range and you boil
them to death, drying them out.
They will have lower and lower capacity
the drier they get.
This type of problem is only found with
a load test. The battery is unusually
strong, almost no sag under load, but
it drops as a rock as soon as the dry
cell has spent its capacity.

If you do not balance, it is easy for 
one or a few cells to hit 2.7V while
you won't see it in the total 200+V
of the long string you have.
I had 312V in 26 x 12V AGMs and had no
clue that the cells in the batteries 
were so far apart until I started 
hurting them.

Regards,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of [email protected]
Sent: Tuesday, February 03, 2009 10:23 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] AGM battery health

It is a heavy vehicle, the Conceptor G-Van.

The charging characteristics are:
T1 (max 10hr)CC-until 257.4V
T2 (max 3hr)CA-until 7.8A
T3 (max 6hr)pulse current @7.8A
The van is parked in a unheated garage,probably 50-55 degrees.

They are 6 volt AGM's, Centennial CBM83CHP06V27.

Todd.

-------- Original Message --------
Subject: Re: [EVDL] AGM battery health
From: "Cor van de Water" <[email protected]>
Date: Mon, February 02, 2009 1:29 pm
To: "Electric Vehicle Discussion List" <[email protected]>

200Ah x 216V = 43kWh nominal, at least 22 kWh usable
without murdering them.
55 miles range means over 400Wh per mile, which is on
the high side.

Either you have a lead foot and many traffic lights
or a very heavy vehicle or it is not tuned to its
optimal performance else you would get more range. 

If you can tell more about the finishing voltage
and duration of the Zivan as well as whether you
park inside or outside in the 40 deg weather, so
we can guesstimate the battery temp....

BTW, it only takes a few too deep discharges or
an unbalanced cell or two to really destroy your
range.

Do you have AGM 6V battery? That is not common...
Which ones are they - not all brands and types
are equal.
Most 6V are flooded (Golf Cart) batteries.

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of [email protected]
Sent: Monday, February 02, 2009 9:54 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] AGM battery health

Thanks for responding Lee.
The batteries are a 200 AH/ 6 volt, 216 volt string. 
Fully charged pack is 236 volts after resting overnight, which is 6.55
volts per battery.
I checked all the batteries voltages, the low was 6.33v and the high was
6.60v, most were around 6.5v.
When the pack was new, I would get 55 miles per charge.
I have put 2800 miles on them. Most trips about 35 miles.
Over a months time it went down to about 10-14 miles per charge.
I use a Zivan charger with CC-CV and a pulse finish ( AGM algorithm)
I am in Phoenix, the night time temps. are in the 40's. Day temps. in
the 70's.
Thanks, Todd.

-------- Original Message --------
Subject: Re: [EVDL] AGM battery health
From: Lee Hart <[email protected]>
Date: Sun, February 01, 2009 7:39 am
To: Electric Vehicle Discussion List <[email protected]>



> Todd [email protected] wrote:
> > What is the best method of checking an AGM battery's health?
> 
> The best method is a load test. Fully charge it, then connect a load
> ...


----------

