[RE-wrenches] Trojan L16RE-2V set-points

[Kevin Pegg]

Hi Mac,

So essentially this unfortunate battery bank was being close to Equalize charged daily for a couple years? Must have gone through a lot of water. I agree with your diagnosis they just cooked them, plates are dissolving = a seriously over-charged and ruined battery bank. Hopefully she doesn't shoot the messenger when you sell a new bank. Only times I would use settings like that is if using PV to recondition some batteries that suffered an opposite fate to this situation of chronic discharge. Even then would only be a couple weeks.

I like the saying ' batteries don't die, they are murdered ' .

Kevin

From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Mac Lewis
Sent: September-11-18 5:44 PM
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Subject: [RE-wrenches] Trojan L16RE-2V set-points

Hello wrenches,

I inspected a system that another company had installed.  It had single string of 12 x Trojan L16RE-2V batteries about 2 years old.  They had experienced a battery melt-down.  It looks as though the meltdown had occurred internally, not from a bad connection.

The system was dual stack Outback VFXR-3524A inverters (to be precise one was a sealed unit).  The set-points were as follows:
Absorb Voltage was 29.8V
Absorb Time was 6.0 hours
Float Voltage was 27.0V
Rebulk Voltage was 27.0V
End Amps was 0A

These settings extended similarly to 2 x FM80 charge controllers.

I was able to jumper the melted battery and get her power in 15 minutes.  Her installer had left her without power for 2 weeks.  My clients will kill me if that happened!

Anyway, I believe these set-points are way out of whack and too aggressive.  The voltage is OK (Trojan recommends ~29.6V for this) but the Absorb time seems way too long, Rebulk is too high and end amps isn't helping.  However, Im not finding a definitive article from Trojan that describes typical Absorb times or even how to adjust towards a good Absorb Time, based on specific gravity measurements or amperage absorption.

My diagnosis is that these batteries have been cooked over the past 2 years.  In the electrolyte, there is noticeable "floaties".  The client said that the original installer had accused her of not using distilled water, but I don't believe that would cause her symptoms.  I believe the floaties are plate material.

I'd be interested in wrenches opinions familiar with these batteries if these are appropriate settings for a low energy user.  I will attempt to get through to Trojan as well.

Thanks in advance



--



Mac Lewis

"Yo solo sé que no sé nada." -Sócrates
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