[AFMUG] Traco TSP+BCM Question
I have a site with a TSP+BCM 48V combo. Last night, something caused the AC breaker to trip, putting the site on battery. We didn't see the alert until about 12 hours later. At this point, the batteries were down to ~42V. When our guy arrived on site, he reset the AC breaker, and AC power was restored. Immediately, the battery breaker (breaker between positive side of the batteries and the BCM) tripped. Now, each time that we reset the battery breaker, it causes the AC breaker to immediately trip. At this point, the site is up on AC with no battery. Any ideas what would be causing this? Do you think the batteries are causing the BCM to draw too much current? Could one (or more) of the batteries be dead/bad? The site *did* run successfully on battery for nearly 12 hours. Josh
Re: [AFMUG] Traco TSP+BCM Question
Might be as simple as your AC circuit is too small for the whole load. The key questions are (1) What is the load of your equipment?, and (2) What is the bulk charge load on your controller? Add those two together to understand what the total load should be. bp On 5/28/2017 9:19 AM, Josh Baird wrote: I have a site with a TSP+BCM 48V combo. Last night, something caused the AC breaker to trip, putting the site on battery. We didn't see the alert until about 12 hours later. At this point, the batteries were down to ~42V. When our guy arrived on site, he reset the AC breaker, and AC power was restored. Immediately, the battery breaker (breaker between positive side of the batteries and the BCM) tripped. Now, each time that we reset the battery breaker, it causes the AC breaker to immediately trip. At this point, the site is up on AC with no battery. Any ideas what would be causing this? Do you think the batteries are causing the BCM to draw too much current? Could one (or more) of the batteries be dead/bad? The site *did* run successfully on battery for nearly 12 hours. Josh
Re: [AFMUG] Traco TSP+BCM Question
This site has about 180-200W of load. The TSP power supply is 360W. I know the BCM has about a ~55W overhead for charging, so that should still leave plenty of headroom, wouldn't you think? On Sun, May 28, 2017 at 1:19 PM, Bill Prince wrote: > Might be as simple as your AC circuit is too small for the whole load. The > key questions are (1) What is the load of your equipment?, and (2) What is > the bulk charge load on your controller? > > Add those two together to understand what the total load should be. > > > bp > > > > On 5/28/2017 9:19 AM, Josh Baird wrote: > >> I have a site with a TSP+BCM 48V combo. Last night, something caused the >> AC breaker to trip, putting the site on battery. We didn't see the alert >> until about 12 hours later. At this point, the batteries were down to >> ~42V. When our guy arrived on site, he reset the AC breaker, and AC power >> was restored. Immediately, the battery breaker (breaker between positive >> side of the batteries and the BCM) tripped. >> >> Now, each time that we reset the battery breaker, it causes the AC >> breaker to immediately trip. At this point, the site is up on AC with no >> battery. Any ideas what would be causing this? Do you think the batteries >> are causing the BCM to draw too much current? Could one (or more) of the >> batteries be dead/bad? The site *did* run successfully on battery for >> nearly 12 hours. >> >> Josh >> > >
Re: [AFMUG] Traco TSP+BCM Question
A 48 volt battery discharged down to 42 volts will be a very very heavy load for whatever is attempting to charge it. A TSP 600-148 will only make 12.5 amps max. Your battery could easily want 25 or 50 amps for the first 10 seconds. It will taper off to zero as it comes up to charge, but the more dead they are, the more they appear to be a dead short to the charger. You have probably never tried to start this system with stoned batts. What is the amp rating of the battery breaker? And the AC side will have a pretty high inrush current as well. Is your AC breaker greater than the power supply inrush current. TSP 600 recommends a 25 amp circuit breaker on 120 VAC. From: Josh Baird Sent: Sunday, May 28, 2017 10:19 AM To: af@afmug.com Subject: [AFMUG] Traco TSP+BCM Question I have a site with a TSP+BCM 48V combo. Last night, something caused the AC breaker to trip, putting the site on battery. We didn't see the alert until about 12 hours later. At this point, the batteries were down to ~42V. When our guy arrived on site, he reset the AC breaker, and AC power was restored. Immediately, the battery breaker (breaker between positive side of the batteries and the BCM) tripped. Now, each time that we reset the battery breaker, it causes the AC breaker to immediately trip. At this point, the site is up on AC with no battery. Any ideas what would be causing this? Do you think the batteries are causing the BCM to draw too much current? Could one (or more) of the batteries be dead/bad? The site *did* run successfully on battery for nearly 12 hours. Josh
Re: [AFMUG] Traco TSP+BCM Question
360 recommends a 16 amp or greater circuit for the AC. And it will only make 7.5 amps. Almost any batter discharged that much will take 100% of that 7.5 amps when starting to charge. I would set the battery circuit breaker to be higher than 7.5 amps to prevent this problem. From: Josh Baird Sent: Sunday, May 28, 2017 11:30 AM To: af@afmug.com Subject: Re: [AFMUG] Traco TSP+BCM Question This site has about 180-200W of load. The TSP power supply is 360W. I know the BCM has about a ~55W overhead for charging, so that should still leave plenty of headroom, wouldn't you think? On Sun, May 28, 2017 at 1:19 PM, Bill Prince wrote: Might be as simple as your AC circuit is too small for the whole load. The key questions are (1) What is the load of your equipment?, and (2) What is the bulk charge load on your controller? Add those two together to understand what the total load should be. bp On 5/28/2017 9:19 AM, Josh Baird wrote: I have a site with a TSP+BCM 48V combo. Last night, something caused the AC breaker to trip, putting the site on battery. We didn't see the alert until about 12 hours later. At this point, the batteries were down to ~42V. When our guy arrived on site, he reset the AC breaker, and AC power was restored. Immediately, the battery breaker (breaker between positive side of the batteries and the BCM) tripped. Now, each time that we reset the battery breaker, it causes the AC breaker to immediately trip. At this point, the site is up on AC with no battery. Any ideas what would be causing this? Do you think the batteries are causing the BCM to draw too much current? Could one (or more) of the batteries be dead/bad? The site *did* run successfully on battery for nearly 12 hours. Josh
Re: [AFMUG] Traco TSP+BCM Question
Ok - so this is what I was thinking. I thought my breakers were rated for much more current, but it looks like they are only rated for 5A (both AC [1] and BATT [2]). In short - I need a breaker that can handle more current, correct? I have these breakers at a ton of sites.. can't believe I just noticed they were only rated for 5A. :( In the meantime, I may need to use an external charger to get these batteries charged back up. [1] http://www.alliedelec.com/altech-corp-2c5um/70076204/ [2] http://www.alliedelec.com/altech-corp-1c5um/70076445/ On Sun, May 28, 2017 at 1:36 PM, Chuck McCown wrote: > 360 recommends a 16 amp or greater circuit for the AC. > And it will only make 7.5 amps. Almost any batter discharged that much > will take 100% of that 7.5 amps when starting to charge. I would set the > battery circuit breaker to be higher than 7.5 amps to prevent this > problem. > > *From:* Josh Baird > *Sent:* Sunday, May 28, 2017 11:30 AM > *To:* af@afmug.com > *Subject:* Re: [AFMUG] Traco TSP+BCM Question > > This site has about 180-200W of load. The TSP power supply is 360W. I > know the BCM has about a ~55W overhead for charging, so that should still > leave plenty of headroom, wouldn't you think? > > On Sun, May 28, 2017 at 1:19 PM, Bill Prince wrote: > >> Might be as simple as your AC circuit is too small for the whole load. >> The key questions are (1) What is the load of your equipment?, and (2) What >> is the bulk charge load on your controller? >> >> Add those two together to understand what the total load should be. >> >> >> bp >> >> >> >> On 5/28/2017 9:19 AM, Josh Baird wrote: >> >>> I have a site with a TSP+BCM 48V combo. Last night, something caused >>> the AC breaker to trip, putting the site on battery. We didn't see the >>> alert until about 12 hours later. At this point, the batteries were down >>> to ~42V. When our guy arrived on site, he reset the AC breaker, and AC >>> power was restored. Immediately, the battery breaker (breaker between >>> positive side of the batteries and the BCM) tripped. >>> >>> Now, each time that we reset the battery breaker, it causes the AC >>> breaker to immediately trip. At this point, the site is up on AC with no >>> battery. Any ideas what would be causing this? Do you think the batteries >>> are causing the BCM to draw too much current? Could one (or more) of the >>> batteries be dead/bad? The site *did* run successfully on battery for >>> nearly 12 hours. >>> >>> Josh >>> >> >> >
Re: [AFMUG] Traco TSP+BCM Question
Yes, minimum of 16 amps for the AC and 7.5 for the DC. And DC breakers are special, do not use an AC breaker on DC. You can short out both breakers with a jumper for for a short amount of time until the batts get a bit of a charge. Probably only take a few minutes. From: Josh Baird Sent: Sunday, May 28, 2017 11:44 AM To: af@afmug.com Subject: Re: [AFMUG] Traco TSP+BCM Question Ok - so this is what I was thinking. I thought my breakers were rated for much more current, but it looks like they are only rated for 5A (both AC [1] and BATT [2]). In short - I need a breaker that can handle more current, correct? I have these breakers at a ton of sites.. can't believe I just noticed they were only rated for 5A. :( In the meantime, I may need to use an external charger to get these batteries charged back up. [1] http://www.alliedelec.com/altech-corp-2c5um/70076204/ [2] http://www.alliedelec.com/altech-corp-1c5um/70076445/ On Sun, May 28, 2017 at 1:36 PM, Chuck McCown wrote: 360 recommends a 16 amp or greater circuit for the AC. And it will only make 7.5 amps. Almost any batter discharged that much will take 100% of that 7.5 amps when starting to charge. I would set the battery circuit breaker to be higher than 7.5 amps to prevent this problem. From: Josh Baird Sent: Sunday, May 28, 2017 11:30 AM To: af@afmug.com Subject: Re: [AFMUG] Traco TSP+BCM Question This site has about 180-200W of load. The TSP power supply is 360W. I know the BCM has about a ~55W overhead for charging, so that should still leave plenty of headroom, wouldn't you think? On Sun, May 28, 2017 at 1:19 PM, Bill Prince wrote: Might be as simple as your AC circuit is too small for the whole load. The key questions are (1) What is the load of your equipment?, and (2) What is the bulk charge load on your controller? Add those two together to understand what the total load should be. bp On 5/28/2017 9:19 AM, Josh Baird wrote: I have a site with a TSP+BCM 48V combo. Last night, something caused the AC breaker to trip, putting the site on battery. We didn't see the alert until about 12 hours later. At this point, the batteries were down to ~42V. When our guy arrived on site, he reset the AC breaker, and AC power was restored. Immediately, the battery breaker (breaker between positive side of the batteries and the BCM) tripped. Now, each time that we reset the battery breaker, it causes the AC breaker to immediately trip. At this point, the site is up on AC with no battery. Any ideas what would be causing this? Do you think the batteries are causing the BCM to draw too much current? Could one (or more) of the batteries be dead/bad? The site *did* run successfully on battery for nearly 12 hours. Josh
Re: [AFMUG] Traco TSP+BCM Question
On 5/28/17 10:44 AM, Josh Baird wrote: Ok - so this is what I was thinking. I thought my breakers were rated for much more current, but it looks like they are only rated for 5A (both AC [1] and BATT [2]). In short - I need a breaker that can handle more current, correct? I have these breakers at a ton of sites.. can't believe I just noticed they were only rated for 5A. :( In the meantime, I may need to use an external charger to get these batteries charged back up. [1] http://www.alliedelec.com/altech-corp-2c5um/70076204/ Other than making sure you have the right size breaker for running load, that's a C curve breaker. Ideally for things with high inrush like power supplies and transformers you should prefer a D curve, which have a higher 100ms trip point at 20xRC. The C curve is 10xRC at 100ms. See the table here: http://www.altechcorp.com/breakers/R-Series.html ~Seth
Re: [AFMUG] Traco TSP+BCM Question
Ok - thanks for the info! It looks like the R-Series breakers are only for AC, though? On the AC side, I'm thinking of this one: http://www.alliedelec.com/altech-corp-2du25r/70075748/ Do you have any suggestions for a single-pol 10A DC breaker that I can use for the BATT side? I'm not finding anything in Altech's lineup that matches these specs. On Sun, May 28, 2017 at 2:20 PM, Seth Mattinen wrote: > On 5/28/17 10:44 AM, Josh Baird wrote: > >> Ok - so this is what I was thinking. I thought my breakers were rated >> for much more current, but it looks like they are only rated for 5A (both >> AC [1] and BATT [2]). >> >> In short - I need a breaker that can handle more current, correct? I >> have these breakers at a ton of sites.. can't believe I just noticed they >> were only rated for 5A. :( In the meantime, I may need to use an external >> charger to get these batteries charged back up. >> >> [1] http://www.alliedelec.com/altech-corp-2c5um/70076204/ >> > > > Other than making sure you have the right size breaker for running load, > that's a C curve breaker. Ideally for things with high inrush like power > supplies and transformers you should prefer a D curve, which have a higher > 100ms trip point at 20xRC. The C curve is 10xRC at 100ms. > > See the table here: > http://www.altechcorp.com/breakers/R-Series.html > > ~Seth >
Re: [AFMUG] Traco TSP+BCM Question
On 5/28/17 11:24 AM, Josh Baird wrote: Ok - thanks for the info! It looks like the R-Series breakers are only for AC, though? On the AC side, I'm thinking of this one: http://www.alliedelec.com/altech-corp-2du25r/70075748/ I thought you were using R series. I glanced at the picture and the letter in the description. V-EA are UL508's for motor disconnect. The UR series is the DC version: http://www.altechcorp.com/breakers/UR-Series.html I also use L or DL series which are UL489. R and UR are UL1077. Difference: http://www.schneider-electric.us/en/faqs/FA145355/ ~Seth
Re: [AFMUG] Traco TSP+BCM Question
On 5/28/17 11:43 AM, Seth Mattinen wrote: The UR series is the DC version: http://www.altechcorp.com/breakers/UR-Series.html Scratch that, that's wrong. I was thinking DL series: http://www.altechcorp.com/breakers/UL-DL-Series.html
Re: [AFMUG] Traco TSP+BCM Question
I have used these for DC: https://www.solar-electric.com/mneac.html From: Josh Baird Sent: Sunday, May 28, 2017 12:24 PM To: af@afmug.com Subject: Re: [AFMUG] Traco TSP+BCM Question Ok - thanks for the info! It looks like the R-Series breakers are only for AC, though? On the AC side, I'm thinking of this one: http://www.alliedelec.com/altech-corp-2du25r/70075748/ Do you have any suggestions for a single-pol 10A DC breaker that I can use for the BATT side? I'm not finding anything in Altech's lineup that matches these specs. On Sun, May 28, 2017 at 2:20 PM, Seth Mattinen wrote: On 5/28/17 10:44 AM, Josh Baird wrote: Ok - so this is what I was thinking. I thought my breakers were rated for much more current, but it looks like they are only rated for 5A (both AC [1] and BATT [2]). In short - I need a breaker that can handle more current, correct? I have these breakers at a ton of sites.. can't believe I just noticed they were only rated for 5A. :( In the meantime, I may need to use an external charger to get these batteries charged back up. [1] http://www.alliedelec.com/altech-corp-2c5um/70076204/ Other than making sure you have the right size breaker for running load, that's a C curve breaker. Ideally for things with high inrush like power supplies and transformers you should prefer a D curve, which have a higher 100ms trip point at 20xRC. The C curve is 10xRC at 100ms. See the table here: http://www.altechcorp.com/breakers/R-Series.html ~Seth
Re: [AFMUG] Traco TSP+BCM Question
Sorry, that was wrong. This is what you want: https://www.solar-electric.com/midnite-solar-mnepv-10-amps-circuit-breaker.html $11.35 and you can buy just one. Din rail mount. Midnite-solar has a full range of these in many different amperage ratings. But until you get one, go to an auto parts store and buy an inline fuse holder with a 10 amp fuse to tide you over. From: Chuck McCown Sent: Sunday, May 28, 2017 1:27 PM To: af@afmug.com Subject: Re: [AFMUG] Traco TSP+BCM Question I have used these for DC: https://www.solar-electric.com/mneac.html From: Josh Baird Sent: Sunday, May 28, 2017 12:24 PM To: af@afmug.com Subject: Re: [AFMUG] Traco TSP+BCM Question Ok - thanks for the info! It looks like the R-Series breakers are only for AC, though? On the AC side, I'm thinking of this one: http://www.alliedelec.com/altech-corp-2du25r/70075748/ Do you have any suggestions for a single-pol 10A DC breaker that I can use for the BATT side? I'm not finding anything in Altech's lineup that matches these specs. On Sun, May 28, 2017 at 2:20 PM, Seth Mattinen wrote: On 5/28/17 10:44 AM, Josh Baird wrote: Ok - so this is what I was thinking. I thought my breakers were rated for much more current, but it looks like they are only rated for 5A (both AC [1] and BATT [2]). In short - I need a breaker that can handle more current, correct? I have these breakers at a ton of sites.. can't believe I just noticed they were only rated for 5A. :( In the meantime, I may need to use an external charger to get these batteries charged back up. [1] http://www.alliedelec.com/altech-corp-2c5um/70076204/ Other than making sure you have the right size breaker for running load, that's a C curve breaker. Ideally for things with high inrush like power supplies and transformers you should prefer a D curve, which have a higher 100ms trip point at 20xRC. The C curve is 10xRC at 100ms. See the table here: http://www.altechcorp.com/breakers/R-Series.html ~Seth
Re: [AFMUG] Traco TSP+BCM Question
A bit lower cost: https://www.invertersupply.com/index.php?main_page=product_info&products_id=5857&gclid=CMr2gOyuk9QCFQ6QaQodFyQDTA From: Chuck McCown Sent: Sunday, May 28, 2017 1:34 PM To: af@afmug.com Subject: Re: [AFMUG] Traco TSP+BCM Question Sorry, that was wrong. This is what you want: https://www.solar-electric.com/midnite-solar-mnepv-10-amps-circuit-breaker.html $11.35 and you can buy just one. Din rail mount. Midnite-solar has a full range of these in many different amperage ratings. But until you get one, go to an auto parts store and buy an inline fuse holder with a 10 amp fuse to tide you over. From: Chuck McCown Sent: Sunday, May 28, 2017 1:27 PM To: af@afmug.com Subject: Re: [AFMUG] Traco TSP+BCM Question I have used these for DC: https://www.solar-electric.com/mneac.html From: Josh Baird Sent: Sunday, May 28, 2017 12:24 PM To: af@afmug.com Subject: Re: [AFMUG] Traco TSP+BCM Question Ok - thanks for the info! It looks like the R-Series breakers are only for AC, though? On the AC side, I'm thinking of this one: http://www.alliedelec.com/altech-corp-2du25r/70075748/ Do you have any suggestions for a single-pol 10A DC breaker that I can use for the BATT side? I'm not finding anything in Altech's lineup that matches these specs. On Sun, May 28, 2017 at 2:20 PM, Seth Mattinen wrote: On 5/28/17 10:44 AM, Josh Baird wrote: Ok - so this is what I was thinking. I thought my breakers were rated for much more current, but it looks like they are only rated for 5A (both AC [1] and BATT [2]). In short - I need a breaker that can handle more current, correct? I have these breakers at a ton of sites.. can't believe I just noticed they were only rated for 5A. :( In the meantime, I may need to use an external charger to get these batteries charged back up. [1] http://www.alliedelec.com/altech-corp-2c5um/70076204/ Other than making sure you have the right size breaker for running load, that's a C curve breaker. Ideally for things with high inrush like power supplies and transformers you should prefer a D curve, which have a higher 100ms trip point at 20xRC. The C curve is 10xRC at 100ms. See the table here: http://www.altechcorp.com/breakers/R-Series.html ~Seth
Re: [AFMUG] Traco TSP+BCM Question
Thanks.. these are *much* cheaper than what I have been using. On Sun, May 28, 2017 at 3:54 PM, Chuck McCown wrote: > A bit lower cost: > https://www.invertersupply.com/index.php?main_page= > product_info&products_id=5857&gclid=CMr2gOyuk9QCFQ6QaQodFyQDTA > > *From:* Chuck McCown > *Sent:* Sunday, May 28, 2017 1:34 PM > *To:* af@afmug.com > *Subject:* Re: [AFMUG] Traco TSP+BCM Question > > Sorry, that was wrong. This is what you want: > https://www.solar-electric.com/midnite-solar-mnepv-10- > amps-circuit-breaker.html > $11.35 and you can buy just one. > Din rail mount. > > Midnite-solar has a full range of these in many different amperage > ratings. > But until you get one, go to an auto parts store and buy an inline fuse > holder with a 10 amp fuse to tide you over. > > *From:* Chuck McCown > *Sent:* Sunday, May 28, 2017 1:27 PM > *To:* af@afmug.com > *Subject:* Re: [AFMUG] Traco TSP+BCM Question > > I have used these for DC: > https://www.solar-electric.com/mneac.html > > *From:* Josh Baird > *Sent:* Sunday, May 28, 2017 12:24 PM > *To:* af@afmug.com > *Subject:* Re: [AFMUG] Traco TSP+BCM Question > > Ok - thanks for the info! It looks like the R-Series breakers are only > for AC, though? On the AC side, I'm thinking of this one: > > http://www.alliedelec.com/altech-corp-2du25r/70075748/ > > Do you have any suggestions for a single-pol 10A DC breaker that I can use > for the BATT side? I'm not finding anything in Altech's lineup that > matches these specs. > > On Sun, May 28, 2017 at 2:20 PM, Seth Mattinen wrote: > >> On 5/28/17 10:44 AM, Josh Baird wrote: >> >>> Ok - so this is what I was thinking. I thought my breakers were rated >>> for much more current, but it looks like they are only rated for 5A (both >>> AC [1] and BATT [2]). >>> >>> In short - I need a breaker that can handle more current, correct? I >>> have these breakers at a ton of sites.. can't believe I just noticed they >>> were only rated for 5A. :( In the meantime, I may need to use an external >>> charger to get these batteries charged back up. >>> >>> [1] http://www.alliedelec.com/altech-corp-2c5um/70076204/ >>> >> >> >> Other than making sure you have the right size breaker for running load, >> that's a C curve breaker. Ideally for things with high inrush like power >> supplies and transformers you should prefer a D curve, which have a higher >> 100ms trip point at 20xRC. The C curve is 10xRC at 100ms. >> >> See the table here: >> http://www.altechcorp.com/breakers/R-Series.html >> >> ~Seth >> > >
Re: [AFMUG] Traco TSP+BCM Question
R Series [1] should be fine for the AC side though, right? [1] http://www.alliedelec.com/altech-corp-2du25r/70075748/ On Sun, May 28, 2017 at 2:43 PM, Seth Mattinen wrote: > On 5/28/17 11:24 AM, Josh Baird wrote: > >> Ok - thanks for the info! It looks like the R-Series breakers are only >> for AC, though? On the AC side, I'm thinking of this one: >> >> http://www.alliedelec.com/altech-corp-2du25r/70075748/ >> > > > > I thought you were using R series. I glanced at the picture and the letter > in the description. V-EA are UL508's for motor disconnect. > > The UR series is the DC version: > http://www.altechcorp.com/breakers/UR-Series.html > > I also use L or DL series which are UL489. R and UR are UL1077. > > Difference: > http://www.schneider-electric.us/en/faqs/FA145355/ > > ~Seth >
Re: [AFMUG] Traco TSP+BCM Question
On 5/28/17 1:11 PM, Josh Baird wrote: R Series [1] should be fine for the AC side though, right? [1] http://www.alliedelec.com/altech-corp-2du25r/70075748/ Yes, fine for AC. You could probably use a smaller breaker in D curve since it's 100ms trip is 20 times rated current. That means a 25A breaker should take <100ms inrush of 500A without tripping. Of course, if you pick a breaker larger than whatever is upstream feeding it then it's just an expensive switch. ~Seth
Re: [AFMUG] Traco TSP+BCM Question
This is why I gave up on the BCM48 and just started using the BCMU360 instead. The regular BCMs seem to have NO charging current limit. Either that or something in them breaks and the results are the same. I cooked a TSP360-148. The one I mentioned a few months ago that screeches on startup. The thing was pushing over 10 amps on the output for 30-40 minutes trying to charge a string I had sitting for a while. I found out just after that one of the batteries was shot. So I'm not sure if that's what screwed up the BCM. This was just sitting on the bench plugged into a 20A recept in the wall. The breaker didn't trip. There's no way in hell I'm putting a regular BCM in the field. I've said this several times. The BCMU360 is rated for 240W continuous and I don't typically load it up with more than ~220W. I use a Mean Well SDR-240-48 instead of a TSP360. It's much cheaper, especially after nuking that first one. On 5/28/2017 12:33 PM, Chuck McCown wrote: A 48 volt battery discharged down to 42 volts will be a very very heavy load for whatever is attempting to charge it. A TSP 600-148 will only make 12.5 amps max. Your battery could easily want 25 or 50 amps for the first 10 seconds. It will taper off to zero as it comes up to charge, but the more dead they are, the more they appear to be a dead short to the charger. You have probably never tried to start this system with stoned batts. What is the amp rating of the battery breaker? And the AC side will have a pretty high inrush current as well. Is your AC breaker greater than the power supply inrush current. TSP 600 recommends a 25 amp circuit breaker on 120 VAC. *From:* Josh Baird *Sent:* Sunday, May 28, 2017 10:19 AM *To:* af@afmug.com *Subject:* [AFMUG] Traco TSP+BCM Question I have a site with a TSP+BCM 48V combo. Last night, something caused the AC breaker to trip, putting the site on battery. We didn't see the alert until about 12 hours later. At this point, the batteries were down to ~42V. When our guy arrived on site, he reset the AC breaker, and AC power was restored. Immediately, the battery breaker (breaker between positive side of the batteries and the BCM) tripped. Now, each time that we reset the battery breaker, it causes the AC breaker to immediately trip. At this point, the site is up on AC with no battery. Any ideas what would be causing this? Do you think the batteries are causing the BCM to draw too much current? Could one (or more) of the batteries be dead/bad? The site *did* run successfully on battery for nearly 12 hours. Josh