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Discussion Starter #1
I have a Zivan NG1 on a 48V system with 6 Trojan T-875s. I also just
installed a PakTrakr and see that on charging the PakTrakr indicates
an overcharging condition on 4 of my 6 batteries. I recorded the
individual battery voltages right near the end of the charging cycle.
The voltages were 10.5, 10.4, 10.2, 10.8, 10.8, 10.6 with a pack
voltage of 63.4v. This is higher than what Trojan's website says. The
charger has a sticker saying that it is for a 48V system with T-875 or
equivalent batteries. Should I be concerned with this? Should I send
the charger back to Zivan for testing/reprograming?

Thank you,

--
David D. Nelson

http://www.austinev.org/evalbum/1328

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Discussion Starter #2
David Nelson wrote:

> I have a Zivan NG1 on a 48V system with 6 Trojan T-875s. I
> also just installed a PakTrakr and see that on charging the
> PakTrakr indicates an overcharging condition on 4 of my 6
> batteries. I recorded the individual battery voltages right
> near the end of the charging cycle.
> The voltages were 10.5, 10.4, 10.2, 10.8, 10.8, 10.6 with a
> pack voltage of 63.4v. This is higher than what Trojan's
> website says. The charger has a sticker saying that it is for
> a 48V system with T-875 or equivalent batteries. Should I be
> concerned with this? Should I send the charger back to Zivan
> for testing/reprograming?

The voltages are OK. 10.8V is 2.7V/cell, which is high, but not at all unbelievable near the end of a charge cycle.

If you haven't yet done so, doublecheck your PakTrakr readings against a good DMM. The PakTrakr only measures to 0.1V and I've found that the readings can vary by +/-0.1-0.2V from channel to channel and monitor to monitor (with the 6-battery monitors; the 8-battery model may be different).

Cheers,

Roger.

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Discussion Starter #3
David Nelson wrote:
> I have a Zivan NG1 on a 48V system with 6 Trojan T-875s. I also just
> installed a PakTrakr and see that on charging the PakTrakr indicates
> an overcharging condition on 4 of my 6 batteries. I recorded the
> individual battery voltages right near the end of the charging cycle.
> The voltages were 10.5, 10.4, 10.2, 10.8, 10.8, 10.6 with a pack
> voltage of 63.4v. This is higher than what Trojan's website says. The
> charger has a sticker saying that it is for a 48V system with T-875 or
> equivalent batteries. Should I be concerned with this? Should I send
> the charger back to Zivan for testing/reprograming?

63.4v on a 48v pack is 2.64v/cell, which is definitely high.

First, look for any obvious explanations. Is this the voltage while
charging a "full" pack at some high current? Is the quite cold? Did you
check your meter readings with another meter?

If none of these are the cause, then I would look into ways to reduce
that charge voltage. These high voltages are OK for a nice new pack when
you want to do a full equalizing charge -- but they will use a lot of
water and beat the pack to an early death from overcharging if done
every time.

--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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