Re: [RE-wrenches] Fwd: Refractometer reading has me stumped
Happy Winter Solstice! Speaking of this, here in Truckee at 6000’ we are seeing snow outside the window, batteries are dipping low, threatening to start the gen set. Even if you’re getting a solid 3 hours of sun a day on that 3.9 kW array say at 80% efficiency, let’s use 48 VDC nominal, that is a unimpressive 183 Ah/d kicking into the 800+ AH new battery. Just plain not enough oomph to bring them up so they’re sagging, especially with that miss matched 6 kW Briggs. The solar is trying but can’t do it. (assuming the loads in the home are above a measly 100 Ah/d or so) here we are seeing about 2 sunny days per week in all these storm cycles. That being said my IBE 2 volt cells still haven’t seen the genny yet. Time to get on the tractor! Chris Worcester Solar Wind Works NABCEP Certified PV Installer Office 530-582-4503 Cell 530-448-9692 Fax 530-582-4603 www.solarwindworks.com ch...@solarwindworks.com From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Allan Sindelar Sent: Monday, December 21, 2015 9:16 AM To: RE-wrenches Subject: [RE-wrenches] Fwd: Refractometer reading has me stumped Wrenches, For years I have carried and used a refractometer to accurately measure SG of FLA batteries. I currently have a decent one, a nearly new Bosch Robinair 75240 that has always performed as intended. A couple of days ago I was hired by another local company to investigate and troubleshoot an off grid system that they had recently installed that was not keeping up with the customer's needs and had crashed. I'll give more details below, but the short question is that on a very cold day, I began measuring the SG of the batteries and got readings of between 1.00 and 1.10 on all of the cells I tested, with no obvious cause. I have never seen this and am stumped as to the cause. I tested SG on about six cells in various locations and got readings nearly identical, and all off the scale on the low side. Note that I used the supplied pipette to sample electrolyte well below the surface of the full cells, and they were lightly gassing at the time, so I don't think that this is simply highly stratified electrolyte. The system: 12 x 327 Sunpower modules (3.9 kW) on fixed rack; Schneider XW6048 with Power Distribution Panel, XW600-80 charge controller, System Control Panel, unused AGS and Schneider's new Conext Battery Monitor. Batteries are two strings of 8 Surrette S550s, for about 32 kw-hours of C/20 storage to 80% DOD. The system has been in operation for only about 3 months. The installation quality is mediocre at best, was located in an unheated TuffShed and is powering a doublewide mobile home. The inverter, controller and SCP were connected by the Xanbus system, but the Conext battery monitor was not. The backup generator was a very basic manual-start 6kW Briggs & Stratton that had not been able to charge through the inverter as the inverter hadn't been properly programmed and would overload it. The site is at about 8,000' elevation, so we estimated about 4kW maximum output at 240V AC. I hadn't seen pictures or been given an accurate component list before arriving on site, so was not fully prepared for what I found. The day was sunny and especially cold - best guess a high in the mid-20s (F). After four hours on site my fingers were too stiff to write normally. The battery SOC monitor indicated 100%, and the SCP bar graph also estimated the batteries to be nearly full. Battery voltage under charge on each 6V battery ranged from a low of 7.38V to a high of 7.50V, with a charge rate low enough to suggest absorption. The batteries had not been equalized since new, but new was claimed to be three months ago, and this appeared accurate. The system owners are new to off grid, and while living frugally, claimed that the system worked well during sunny periods but had crashed on about the second day of cloudy weather. They had been using the forced air furnace, and when I arrived had a heat lamp (not labeled as to watts, but I assume 250W 130V) inside the leaky battery box, shining on some of the batteries. As an aside, the 600V Schneider controller has no built-in display/interface, so there was no easy way to determine the charge mode or anything else except through the System Control Panel. That seems pretty bogus to me. I had not seen one of these previously, nor had I seen Schneider's shunt-based SOC meter. When I have installed XWs and SW Conexts I have always used Midnite E-Panels, which have conventional 500A shunts, and TriMetrics to offer accurate SOC for the customer. The system settings all appeared to be set to default, other than "flooded" for battery type. Here are the changes I made in the setup. A couple of things I noticed: 1) with a default LBCO of 40.0V, on at least two occasions the batteries had been completely drained, and had been recharged only by the (substantial) array; but as the array i
Re: [RE-wrenches] Fwd: Refractometer reading has me stumped
Trust your tools. As you know, low SG means the acid is in the form of lead sulfate. Were these dry charged Surrettes? What environment and how long did the batteries set from the date of manufacturer to the date of commissioning the system? Even 120 day old batteries can begin to show problems from deficit charging which includes no or improper equalization. This can cause difficulty reaching the CV set point with unequal cell voltage while charging. Even though these are “new” batteries, perhaps a corrective equalization is needed to drive the SG back up: http://support.rollsbattery.com/support/solutions/articles/430-corrective-equalization-instructionsI recommend a long equalization process Larry Crutcher Starlight Solar Power Systems On Dec 21, 2015, at 10:16 AM, Allan Sindelar wrote: Wrenches, For years I have carried and used a refractometer to accurately measure SG of FLA batteries. I currently have a decent one, a nearly new Bosch Robinair 75240 that has always performed as intended. A couple of days ago I was hired by another local company to investigate and troubleshoot an off grid system that they had recently installed that was not keeping up with the customer's needs and had crashed. I'll give more details below, but the short question is that on a very cold day, I began measuring the SG of the batteries and got readings of between 1.00 and 1.10 on all of the cells I tested, with no obvious cause. I have never seen this and am stumped as to the cause. I tested SG on about six cells in various locations and got readings nearly identical, and all off the scale on the low side. Note that I used the supplied pipette to sample electrolyte well below the surface of the full cells, and they were lightly gassing at the time, so I don't think that this is simply highly stratified electrolyte. The system: 12 x 327 Sunpower modules (3.9 kW) on fixed rack; Schneider XW6048 with Power Distribution Panel, XW600-80 charge controller, System Control Panel, unused AGS and Schneider's new Conext Battery Monitor. Batteries are two strings of 8 Surrette S550s, for about 32 kw-hours of C/20 storage to 80% DOD. The system has been in operation for only about 3 months. The installation quality is mediocre at best, was located in an unheated TuffShed and is powering a doublewide mobile home. The inverter, controller and SCP were connected by the Xanbus system, but the Conext battery monitor was not. The backup generator was a very basic manual-start 6kW Briggs & Stratton that had not been able to charge through the inverter as the inverter hadn't been properly programmed and would overload it. The site is at about 8,000' elevation, so we estimated about 4kW maximum output at 240V AC. I hadn't seen pictures or been given an accurate component list before arriving on site, so was not fully prepared for what I found. The day was sunny and especially cold - best guess a high in the mid-20s (F). After four hours on site my fingers were too stiff to write normally. The battery SOC monitor indicated 100%, and the SCP bar graph also estimated the batteries to be nearly full. Battery voltage under charge on each 6V battery ranged from a low of 7.38V to a high of 7.50V, with a charge rate low enough to suggest absorption. The batteries had not been equalized since new, but new was claimed to be three months ago, and this appeared accurate. The system owners are new to off grid, and while living frugally, claimed that the system worked well during sunny periods but had crashed on about the second day of cloudy weather. They had been using the forced air furnace, and when I arrived had a heat lamp (not labeled as to watts, but I assume 250W 130V) inside the leaky battery box, shining on some of the batteries. As an aside, the 600V Schneider controller has no built-in display/interface, so there was no easy way to determine the charge mode or anything else except through the System Control Panel. That seems pretty bogus to me. I had not seen one of these previously, nor had I seen Schneider's shunt-based SOC meter. When I have installed XWs and SW Conexts I have always used Midnite E-Panels, which have conventional 500A shunts, and TriMetrics to offer accurate SOC for the customer. The system settings all appeared to be set to default, other than "flooded" for battery type. Here are the changes I made in the setup. A couple of things I noticed: 1) with a default LBCO of 40.0V, on at least two occasions the batteries had been completely drained, and had been recharged only by the (substantial) array; but as the array is in theory (3.9kW/58V = 65A in good sun, or a c/12 charge rate, this suggests that even empty batteries will be recharged to full in 2-3 days. 2) battery capacity was set at default of 440AH, when it was actually about 850AH,so the charge rate would have tapered prematurely. 3) The bulk voltage was the default for 'flooded' -
Re: [RE-wrenches] Fwd: Refractometer reading has me stumped
Hi Allan, Thanks for the complete data situation, amazing as always. As usual lots of basic problems that are so avoidable. I remember someone, on this list mentioned that refractometers are damaged by getting too cold and that they won't read correctly I can't find that info however. As the situation is unclear, I would check with a fluid hydrometer to double check your battery SG results. Jay > On Dec 21, 2015, at 9:16 AM, Allan Sindelar wrote: > > Wrenches, > For years I have carried and used a refractometer to accurately measure SG of > FLA batteries. I currently have a decent one, a nearly new Bosch Robinair > 75240 that has always performed as intended. > > A couple of days ago I was hired by another local company to investigate and > troubleshoot an off grid system that they had recently installed that was not > keeping up with the customer's needs and had crashed. I'll give more details > below, but the short question is that on a very cold day, I began measuring > the SG of the batteries and got readings of between 1.00 and 1.10 on all of > the cells I tested, with no obvious cause. I have never seen this and am > stumped as to the cause. I tested SG on about six cells in various locations > and got readings nearly identical, and all off the scale on the low side. > Note that I used the supplied pipette to sample electrolyte well below the > surface of the full cells, and they were lightly gassing at the time, so I > don't think that this is simply highly stratified electrolyte. > > The system: 12 x 327 Sunpower modules (3.9 kW) on fixed rack; Schneider > XW6048 with Power Distribution Panel, XW600-80 charge controller, System > Control Panel, unused AGS and Schneider's new Conext Battery Monitor. > Batteries are two strings of 8 Surrette S550s, for about 32 kw-hours of C/20 > storage to 80% DOD. The system has been in operation for only about 3 months. > The installation quality is mediocre at best, was located in an unheated > TuffShed and is powering a doublewide mobile home. The inverter, controller > and SCP were connected by the Xanbus system, but the Conext battery monitor > was not. > > The backup generator was a very basic manual-start 6kW Briggs & Stratton that > had not been able to charge through the inverter as the inverter hadn't been > properly programmed and would overload it. The site is at about 8,000' > elevation, so we estimated about 4kW maximum output at 240V AC. > > I hadn't seen pictures or been given an accurate component list before > arriving on site, so was not fully prepared for what I found. The day was > sunny and especially cold - best guess a high in the mid-20s (F). After four > hours on site my fingers were too stiff to write normally. The battery SOC > monitor indicated 100%, and the SCP bar graph also estimated the batteries to > be nearly full. Battery voltage under charge on each 6V battery ranged from a > low of 7.38V to a high of 7.50V, with a charge rate low enough to suggest > absorption. The batteries had not been equalized since new, but new was > claimed to be three months ago, and this appeared accurate. > > The system owners are new to off grid, and while living frugally, claimed > that the system worked well during sunny periods but had crashed on about the > second day of cloudy weather. They had been using the forced air furnace, and > when I arrived had a heat lamp (not labeled as to watts, but I assume 250W > 130V) inside the leaky battery box, shining on some of the batteries. > > As an aside, the 600V Schneider controller has no built-in display/interface, > so there was no easy way to determine the charge mode or anything else except > through the System Control Panel. That seems pretty bogus to me. I had not > seen one of these previously, nor had I seen Schneider's shunt-based SOC > meter. When I have installed XWs and SW Conexts I have always used Midnite > E-Panels, which have conventional 500A shunts, and TriMetrics to offer > accurate SOC for the customer. > > The system settings all appeared to be set to default, other than "flooded" > for battery type. Here are the changes I made in the setup. A couple of > things I noticed: > 1) with a default LBCO of 40.0V, on at least two occasions the batteries > had been completely drained, and had been recharged only by the (substantial) > array; but as the array is in theory (3.9kW/58V = 65A in good sun, or a c/12 > charge rate, this suggests that even empty batteries will be recharged to > full in 2-3 days. > 2) battery capacity was set at default of 440AH, when it was actually > about 850AH,so the charge rate would have tapered prematurely. > 3) The bulk voltage was the default for 'flooded' - I don't know the > default, as it isn't given in the XW manual and I changed it to 'custom'. I > assume about 58.4V. > > Setting name Previous > setting
Re: [RE-wrenches] Fwd: Refractometer reading has me stumped
1.000 SG is water & 1.100 SG is like mild vinegar. Dana Orzel Great Solar Works, Inc - NABCEP # 051112-136 E - d...@solarwork.com - Web - solarwork.com O - 970.626.5253 C - 208.721.7003 "Responsible Technologies for Responsible People since 1988" P Please consider the environment before printing this email. From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Allan Sindelar Sent: Monday, December 21, 2015 10:16 AM To: RE-wrenches Subject: [RE-wrenches] Fwd: Refractometer reading has me stumped Wrenches, For years I have carried and used a refractometer to accurately measure SG of FLA batteries. I currently have a decent one, a nearly new Bosch Robinair 75240 that has always performed as intended. A couple of days ago I was hired by another local company to investigate and troubleshoot an off grid system that they had recently installed that was not keeping up with the customer's needs and had crashed. I'll give more details below, but the short question is that on a very cold day, I began measuring the SG of the batteries and got readings of between 1.00 and 1.10 on all of the cells I tested, with no obvious cause. I have never seen this and am stumped as to the cause. I tested SG on about six cells in various locations and got readings nearly identical, and all off the scale on the low side. Note that I used the supplied pipette to sample electrolyte well below the surface of the full cells, and they were lightly gassing at the time, so I don't think that this is simply highly stratified electrolyte. The system: 12 x 327 Sunpower modules (3.9 kW) on fixed rack; Schneider XW6048 with Power Distribution Panel, XW600-80 charge controller, System Control Panel, unused AGS and Schneider's new Conext Battery Monitor. Batteries are two strings of 8 Surrette S550s, for about 32 kw-hours of C/20 storage to 80% DOD. The system has been in operation for only about 3 months. The installation quality is mediocre at best, was located in an unheated TuffShed and is powering a doublewide mobile home. The inverter, controller and SCP were connected by the Xanbus system, but the Conext battery monitor was not. The backup generator was a very basic manual-start 6kW Briggs & Stratton that had not been able to charge through the inverter as the inverter hadn't been properly programmed and would overload it. The site is at about 8,000' elevation, so we estimated about 4kW maximum output at 240V AC. I hadn't seen pictures or been given an accurate component list before arriving on site, so was not fully prepared for what I found. The day was sunny and especially cold - best guess a high in the mid-20s (F). After four hours on site my fingers were too stiff to write normally. The battery SOC monitor indicated 100%, and the SCP bar graph also estimated the batteries to be nearly full. Battery voltage under charge on each 6V battery ranged from a low of 7.38V to a high of 7.50V, with a charge rate low enough to suggest absorption. The batteries had not been equalized since new, but new was claimed to be three months ago, and this appeared accurate. The system owners are new to off grid, and while living frugally, claimed that the system worked well during sunny periods but had crashed on about the second day of cloudy weather. They had been using the forced air furnace, and when I arrived had a heat lamp (not labeled as to watts, but I assume 250W 130V) inside the leaky battery box, shining on some of the batteries. As an aside, the 600V Schneider controller has no built-in display/interface, so there was no easy way to determine the charge mode or anything else except through the System Control Panel. That seems pretty bogus to me. I had not seen one of these previously, nor had I seen Schneider's shunt-based SOC meter. When I have installed XWs and SW Conexts I have always used Midnite E-Panels, which have conventional 500A shunts, and TriMetrics to offer accurate SOC for the customer. The system settings all appeared to be set to default, other than "flooded" for battery type. Here are the changes I made in the setup. A couple of things I noticed: 1) with a default LBCO of 40.0V, on at least two occasions the batteries had been completely drained, and had been recharged only by the (substantial) array; but as the array is in theory (3.9kW/58V = 65A in good sun, or a c/12 charge rate, this suggests that even empty batteries will be recharged to full in 2-3 days. 2) battery capacity was set at default of 440AH, when it was actually about 850AH,so the charge rate would have tapered prematurely. 3) The bulk voltage was the default for 'flooded' - I don't know the default, as it isn't given in the XW manual and I changed it to 'custom'. I assume about 58.4V. Setting name Previou
Re: [RE-wrenches] Fwd: Refractometer reading has me stumped
Allan; Wow, that's a nightmare. All I can suggest for now is to X out some obvious things and CYA. Sounds like you are CY someone else's A now. I get these sort of calls too. Usually it's a townie PV installer who knows nothing about off grid and programmed some equipment wrong. ~ measurement error? did you calibrate the refractometer with distilled water before your tests? Do you have a float hydrometer for backup? ~ did you check SG on *every* cell? one bad one can ruin the whole bunch. ~ Did you view the battery bank on a thermal imager whilst charging or discharging? ~ Isolate and load test a battery. I have a nifty antique adjustable load tester that does this, but any DC load will do it. I'd shoot for a C/5 - C/10 rate. With SG that low, you should know in a couple hours if it has any capacity left at all. ~ Can you put a non-system-integrated coulomb counter SOC meter into the system? Remove it later, just use for diagnostics? My gut feeling is that for some reason, maybe programming of that mishmash of equipment, either the PV array or generator or both is not charging correctly, and these batteries have been starving. Or that there's one really bad cell that's milking them down. I think I'd hit my thermal imager first thing on this one. Good luck! Keep us posted! I love this list because i can learn from everyone else. Dan Fink Adjunct Professor, Ecotech Institute IREC Certified Instructor™ for: ~ PV Installation Professional ~ Small Wind Installer Executive Director, Buckville Energy NABCEP Accredited Continuing Education Providers™ 970.672.4342 On Mon, Dec 21, 2015 at 10:16 AM, Allan Sindelar wrote: > Wrenches, > For years I have carried and used a refractometer to accurately measure SG > of FLA batteries. I currently have a decent one, a nearly new Bosch > Robinair 75240 that has always performed as intended. > > A couple of days ago I was hired by another local company to investigate > and troubleshoot an off grid system that they had recently installed that > was not keeping up with the customer's needs and had crashed. I'll give > more details below, but the short question is that on a very cold day, I > began measuring the SG of the batteries and got readings of between 1.00 > and 1.10 on all of the cells I tested, with no obvious cause. I have never > seen this and am stumped as to the cause. I tested SG on about six cells in > various locations and got readings nearly identical, and all off the scale > on the low side. Note that I used the supplied pipette to sample > electrolyte well below the surface of the full cells, and they were lightly > gassing at the time, so I don't think that this is simply highly stratified > electrolyte. > > The system: 12 x 327 Sunpower modules (3.9 kW) on fixed rack; Schneider > XW6048 with Power Distribution Panel, XW600-80 charge controller, System > Control Panel, unused AGS and Schneider's new Conext Battery Monitor. > Batteries are two strings of 8 Surrette S550s, for about 32 kw-hours of > C/20 storage to 80% DOD. The system has been in operation for only about 3 > months. The installation quality is mediocre at best, was located in an > unheated TuffShed and is powering a doublewide mobile home. The inverter, > controller and SCP were connected by the Xanbus system, but the Conext > battery monitor was not. > > The backup generator was a very basic manual-start 6kW Briggs & Stratton > that had not been able to charge through the inverter as the inverter > hadn't been properly programmed and would overload it. The site is at about > 8,000' elevation, so we estimated about 4kW maximum output at 240V AC. > > I hadn't seen pictures or been given an accurate component list before > arriving on site, so was not fully prepared for what I found. The day was > sunny and especially cold - best guess a high in the mid-20s (F). After > four hours on site my fingers were too stiff to write normally. The battery > SOC monitor indicated 100%, and the SCP bar graph also estimated the > batteries to be nearly full. Battery voltage under charge on each 6V > battery ranged from a low of 7.38V to a high of 7.50V, with a charge rate > low enough to suggest absorption. The batteries had not been equalized > since new, but new was claimed to be three months ago, and this appeared > accurate. > > The system owners are new to off grid, and while living frugally, claimed > that the system worked well during sunny periods but had crashed on about > the second day of cloudy weather. They had been using the forced air > furnace, and when I arrived had a heat lamp (not labeled as to watts, but I > assume 250W 130V) inside the leaky battery box, shining on some of the > batteries. > > As an aside, the 600V Schneider controller has no built-in > display/interface, so there was no easy way to determine the charge mode or > anything else except through the System Control Panel. That seems pretty > bogus to me. I had not seen one of these previously, nor had I seen > Schneider
