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Surrette Warranty Claim

Phase A:  On 8/20/21 we ordered 16 Surrette S6-460AGM batteries from Northern Arizona Wind and Sum for an off-grid client. The sales order number is S112463. NAWS did not have 16 in stock so the order was reduced to 8 batteries.  At the time the client’s existing batteries were beyond usable lifespan and we needed to keep their power on so the 8 batteries were ordered as a temporary measure.  We planned on ordering an additional 8 batteries as soon as they became available and installing them as soon as possible before the first set of batteries aged.

Wiring:  The original 8 batteries were wired in series, as indicated in the diagram below. (Click any thumbnail to enlarge.)

Phase A diagram and photograph

Programming:  The application is an off-grid system with 4 Outback XFR3048A inverters and 1 Outback Extreme Charge controller. The system was programmed as indicated in the images below.  Note that the bulk and float values comply with the specifications on the manufacturer’s data sheet:  The bulk voltage as specified on the data sheet as 2.45 VDC per cell:  2.45 * 24 = 58.8.  The float voltage on the data sheet is 2.3 VDC per cell: 2.3 * 24 = 55.2.  These batteries have never been equalized.

Inverter Programming Chart

Charge Controller Programming Chart

Manufacturer’s data sheet, highlighted

Ventilation:  There is a minimum of 5/8” between each battery.  The battery enclosure has four generous passive vents.

Temperature compensation:  An Outback Remote Temperature Sensor was placed on the back of a battery in the back row about midway between the top and bottom of the battery.

Phase B:  We checked back periodically with NAWS and on 2/3/22 we ordered an additional 8 S6-460AGM batteries, sales order number S121359.  There was some delay in shipping.  These were installed on 3/10/22. 

Wiring:  The new batteries and old batteries were split equally between the two strings. This was done to keep the characteristics of the two strings even.  See diagram below.  Batteries numbered 1 through 8 are the first set.

Phase B diagram and photograph

Problem:  In mid-July 2022 the client noticed some of the batteries were bulging on their tops.  I inspected them on 7/22/22 and verified that about half of the batteries are bulging noticeably.  I checked all settings and connections and found all as they should be.  See images below.

Battery Bulging

Battery Bulging

Open Circuit voltage readings:  I checked open circuit voltages and found the readings as depicted in the drawing below.

Open Circuit Voltage Readings

Request:  We request that the details of this installation be reviewed.  We suspect the charge settings as specified by the manufacturer may be too high.  These batteries bulk charge fully every day and we think they were overcharged.  We have since reduced the charge voltage to 57.6.  We suspect these batteries may not give full performance and should be replaced under warranty.