On Saturday, 29 August 2020 12:21:49 UTC+1, none albert wrote:> In article <d95655fb-7655-4156-a1b7-44ae2f89379co@googlegroups.com>, > Tabby <tabbypurr> wrote: > >On Friday, 28 August 2020 19:50:55 UTC+1, Chris wrote: > >> On 08/27/20 01:30, Tabby wrote: > > > >> > Cart with 2x 12v 33Ah progolf AGM lead acids. 1.5 years after > >fitting new batteries the available range is down to below 10%. I'm not > >clear what's gone wrong. > >> > > >> > The charger in use has been a cheap chinese one with 2x13.7v=27.4v > >output. Single stage charging only. It has always been promptly charged > >after use, and never run below 50% charge. > >> > > >> > I checked the battery voltages after charge, they were 13.6& 13.8v. > >Charged each battery independantly to 15.2v, which took maybe half an > >hour or so. No range improvement. > >> > > >> > When apparently flat the batteries read, offload, 12.3v& 12.8v. I > >expected to see lower. > >> > > >> > What's going on here? > >> > > >> > > >> > NT > >> > >> The data sheets for the better brands of the gel cell types have > >> a graph showing expected life vs number of charge / recharge > >> cycles. Typical design life for ups float applications can be as much > >> as 10 years, but under regular cycling, can be << 5 years. > >> The deeper the discharge, the more detrimental the effect. > >> Carts must hammer batteries pretty hard, especially if they skimp on > >> a/h capacity to keep costs down. 38ah doesn't sound like much for > >> what must be a 1/2 to 1hp motor, at 24 v, 1hp ~= 30 amp, then you > >> have the much higher startup current. You get what you pay for, but > >> Yuasa at least have different optimised types depending on type of > >> service. > >> > >> I would put in bigger batteries, say 100 ah might work a lot better... > >> > >> Chris > > > >2x 100Ah adds a ton of weight. Range is not a problem, depth of > >discharge is usually fine, just occasionally pushed. Looks like it > >mainly needs a reasonably decent charger. > > Where did I get the idea that car batteries, golf cart batteries > and marine boat batteries all have fundamentally different designs? > Where did I hear that golf cart batteries can be routinely discharged > to about 10.5 volt, which would kill a car battery?Battery mfrs & books on lead acids presumably. These ones are gone at 12.3v. Not entirely sure why.> At least you should not head any generic advice about handling > batteries, i.e. advise that doesnot address the specific battery you have. > > You may assume that golf cart batteries are okay for golf carts.I doubt car batteries would last long on it.> >1hp? Dunno but I doubt it. The onboard breaker is 30A. > > > > > >NT > > Groetjes Albert
Lead Acid puzzle
Started by ●August 26, 2020
Reply by ●August 29, 20202020-08-29
Reply by ●August 29, 20202020-08-29
On Friday, August 28, 2020 at 7:23:27 PM UTC-7, Tabby wrote:> On Friday, 28 August 2020 01:30:59 UTC+1, Flyguy wrote: > > On Thursday, August 27, 2020 at 4:51:35 AM UTC-7, Martin Brown wrote: > > > On 27/08/2020 01:30, Tabby wrote: > > > > > Cart with 2x 12v 33Ah progolf AGM lead acids. 1.5 years after fitting new batteries the available range is down to below 10%. I'm not clear what's gone wrong. > > > > > > > > The charger in use has been a cheap chinese one with 2x13.7v=27.4v output. Single stage charging only. It has always been promptly charged after use, and never run below 50% charge. > > > > > > > > I checked the battery voltages after charge, they were 13.6 & 13.8v. Charged each battery independantly to 15.2v, which took maybe half an hour or so. No range improvement. > > > > > > > > When apparently flat the batteries read, offload, 12.3v & 12.8v. I expected to see lower. > > > > > > > > What's going on here? > > > > Battery abuse. The cheap charger has knackered both of your batteries. > > > > > > Recharging lead acid cells for maximum longevity requires some form of > > > thermal compensation of the voltage per cell during charging. eg > > > > > > https://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures > > > > > > Too much over voltage and they gas. Incorrect treatment on top up and > > > they sulphate or corrode internally either way you do damage to them. > > > The weakest cell in a chain fails first and the others then wreck it. > > > > > > -- > > > Regards, > > > Martin Brown > > > > Temperature compensation during charging is vital to maintaining the health of a battery, and they are available: > > http://www.chargingchargers.com/chargers/golf-cart/48-volt-yamaha-18.html > > You must have a REALLY old cart, being 24V. > It's 48v, 115v and $459, no use on 3 counts. The ones nearer what I'm looking for lack temp compensation. > > > NTThat was exemplary of a temperature compensated charger - OF COURSE it won't work for you. There are plenty of 24V battery chargers out there: https://www.amazon.com/24-volt-battery-charger/s?k=24+volt+battery+charger
Reply by ●August 30, 20202020-08-30
On Saturday, 29 August 2020 18:30:03 UTC+1, Flyguy wrote:> On Friday, August 28, 2020 at 7:23:27 PM UTC-7, Tabby wrote: > > On Friday, 28 August 2020 01:30:59 UTC+1, Flyguy wrote: > > > On Thursday, August 27, 2020 at 4:51:35 AM UTC-7, Martin Brown wrote: > > > > On 27/08/2020 01:30, Tabby wrote: > > > > > > > Cart with 2x 12v 33Ah progolf AGM lead acids. 1.5 years after fitting new batteries the available range is down to below 10%. I'm not clear what's gone wrong. > > > > > > > > > > The charger in use has been a cheap chinese one with 2x13.7v=27.4v output. Single stage charging only. It has always been promptly charged after use, and never run below 50% charge. > > > > > > > > > > I checked the battery voltages after charge, they were 13.6 & 13.8v. Charged each battery independantly to 15.2v, which took maybe half an hour or so. No range improvement. > > > > > > > > > > When apparently flat the batteries read, offload, 12.3v & 12.8v. I expected to see lower. > > > > > > > > > > What's going on here? > > > > > > Battery abuse. The cheap charger has knackered both of your batteries. > > > > > > > > Recharging lead acid cells for maximum longevity requires some form of > > > > thermal compensation of the voltage per cell during charging. eg > > > > > > > > https://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures > > > > > > > > Too much over voltage and they gas. Incorrect treatment on top up and > > > > they sulphate or corrode internally either way you do damage to them. > > > > The weakest cell in a chain fails first and the others then wreck it. > > > > > > > > -- > > > > Regards, > > > > Martin Brown > > > > > > Temperature compensation during charging is vital to maintaining the health of a battery, and they are available: > > > http://www.chargingchargers.com/chargers/golf-cart/48-volt-yamaha-18.html > > > You must have a REALLY old cart, being 24V. > > It's 48v, 115v and $459, no use on 3 counts. The ones nearer what I'm looking for lack temp compensation. > > > > > > NT > > That was exemplary of a temperature compensated charger - OF COURSE it won't work for you. There are plenty of 24V battery chargers out there: > https://www.amazon.com/24-volt-battery-charger/s?k=24+volt+battery+chargerOf course there are. On that page: 1. no V_out data, no temp comp, 110v only 2. adpow: too high V_out for flooded cells 3. $668 4. noco: no 24v AGM mode, no temp comp 5. topac: no V_out data, no temp comp 6. V_out too high & not temp comp 7. noco: $229 8. beeleb: no V_out data, claims unsuited to <40Ah. 9. AIMS: $229 10. Genie $292 11. promariner: no V_out data, no temp comp 12. 6/12v only 13. same as 1 14. Promariner: all charge options too high V_out & well north of $200. 15. Promariner: no data 16. Beeleb again 17. LST: no V data, no temp comp 18. Adpow V_out too high, no temp comp, warns that it overcharges 19. V_out too high, no temp comp 20. Beeleb again 21. Renogy: DC input, no temp comp 22. schumacher: not a charger etc etc etc. NT
Reply by ●August 30, 20202020-08-30
On Saturday, August 29, 2020 at 10:39:31 PM UTC-7, Tabby wrote:> On Saturday, 29 August 2020 18:30:03 UTC+1, Flyguy wrote: > > On Friday, August 28, 2020 at 7:23:27 PM UTC-7, Tabby wrote: > > > On Friday, 28 August 2020 01:30:59 UTC+1, Flyguy wrote: > > > > On Thursday, August 27, 2020 at 4:51:35 AM UTC-7, Martin Brown wrote: > > > > > On 27/08/2020 01:30, Tabby wrote: > > > > > > > > > Cart with 2x 12v 33Ah progolf AGM lead acids. 1.5 years after fitting new batteries the available range is down to below 10%. I'm not clear what's gone wrong. > > > > > > > > > > > > The charger in use has been a cheap chinese one with 2x13.7v=27.4v output. Single stage charging only. It has always been promptly charged after use, and never run below 50% charge. > > > > > > > > > > > > I checked the battery voltages after charge, they were 13.6 & 13.8v. Charged each battery independantly to 15.2v, which took maybe half an hour or so. No range improvement. > > > > > > > > > > > > When apparently flat the batteries read, offload, 12.3v & 12.8v. I expected to see lower. > > > > > > > > > > > > What's going on here? > > > > > > > > Battery abuse. The cheap charger has knackered both of your batteries. > > > > > > > > > > Recharging lead acid cells for maximum longevity requires some form of > > > > > thermal compensation of the voltage per cell during charging. eg > > > > > > > > > > https://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures > > > > > > > > > > Too much over voltage and they gas. Incorrect treatment on top up and > > > > > they sulphate or corrode internally either way you do damage to them. > > > > > The weakest cell in a chain fails first and the others then wreck it. > > > > > > > > > > -- > > > > > Regards, > > > > > Martin Brown > > > > > > > > Temperature compensation during charging is vital to maintaining the health of a battery, and they are available: > > > > http://www.chargingchargers.com/chargers/golf-cart/48-volt-yamaha-18.html > > > > You must have a REALLY old cart, being 24V. > > > It's 48v, 115v and $459, no use on 3 counts. The ones nearer what I'm looking for lack temp compensation. > > > > > > > > > NT > > > > That was exemplary of a temperature compensated charger - OF COURSE it won't work for you. There are plenty of 24V battery chargers out there: > > https://www.amazon.com/24-volt-battery-charger/s?k=24+volt+battery+charger > Of course there are. On that page: > > 1. no V_out data, no temp comp, 110v only > 2. adpow: too high V_out for flooded cells > 3. $668 > 4. noco: no 24v AGM mode, no temp comp > 5. topac: no V_out data, no temp comp > 6. V_out too high & not temp comp > 7. noco: $229 > 8. beeleb: no V_out data, claims unsuited to <40Ah. > 9. AIMS: $229 > 10. Genie $292 > 11. promariner: no V_out data, no temp comp > 12. 6/12v only > 13. same as 1 > 14. Promariner: all charge options too high V_out & well north of $200. > 15. Promariner: no data > 16. Beeleb again > 17. LST: no V data, no temp comp > 18. Adpow V_out too high, no temp comp, warns that it overcharges > 19. V_out too high, no temp comp > 20. Beeleb again > 21. Renogy: DC input, no temp comp > 22. schumacher: not a charger > > etc etc etc. > > > NTNot sure what you mean by "no V_out data" Beeleb says it is suited for 2 to 200AH.
Reply by ●August 30, 20202020-08-30
On Sunday, 30 August 2020 06:54:02 UTC+1, Flyguy wrote:> On Saturday, August 29, 2020 at 10:39:31 PM UTC-7, Tabby wrote: > > On Saturday, 29 August 2020 18:30:03 UTC+1, Flyguy wrote: > > > On Friday, August 28, 2020 at 7:23:27 PM UTC-7, Tabby wrote: > > > > On Friday, 28 August 2020 01:30:59 UTC+1, Flyguy wrote: > > > > > On Thursday, August 27, 2020 at 4:51:35 AM UTC-7, Martin Brown wrote: > > > > > > On 27/08/2020 01:30, Tabby wrote: > > > > > > > > > > > Cart with 2x 12v 33Ah progolf AGM lead acids. 1.5 years after fitting new batteries the available range is down to below 10%. I'm not clear what's gone wrong. > > > > > > > > > > > > > > The charger in use has been a cheap chinese one with 2x13.7v=27.4v output. Single stage charging only. It has always been promptly charged after use, and never run below 50% charge. > > > > > > > > > > > > > > I checked the battery voltages after charge, they were 13.6 & 13.8v. Charged each battery independantly to 15.2v, which took maybe half an hour or so. No range improvement. > > > > > > > > > > > > > > When apparently flat the batteries read, offload, 12.3v & 12.8v. I expected to see lower. > > > > > > > > > > > > > > What's going on here? > > > > > > > > > > Battery abuse. The cheap charger has knackered both of your batteries. > > > > > > > > > > > > Recharging lead acid cells for maximum longevity requires some form of > > > > > > thermal compensation of the voltage per cell during charging. eg > > > > > > > > > > > > https://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures > > > > > > > > > > > > Too much over voltage and they gas. Incorrect treatment on top up and > > > > > > they sulphate or corrode internally either way you do damage to them. > > > > > > The weakest cell in a chain fails first and the others then wreck it. > > > > > > > > > > > > -- > > > > > > Regards, > > > > > > Martin Brown > > > > > > > > > > Temperature compensation during charging is vital to maintaining the health of a battery, and they are available: > > > > > http://www.chargingchargers.com/chargers/golf-cart/48-volt-yamaha-18.html > > > > > You must have a REALLY old cart, being 24V. > > > > It's 48v, 115v and $459, no use on 3 counts. The ones nearer what I'm looking for lack temp compensation. > > > > > > > > > > > > NT > > > > > > That was exemplary of a temperature compensated charger - OF COURSE it won't work for you. There are plenty of 24V battery chargers out there: > > > https://www.amazon.com/24-volt-battery-charger/s?k=24+volt+battery+charger > > Of course there are. On that page: > > > > 1. no V_out data, no temp comp, 110v only > > 2. adpow: too high V_out for flooded cells > > 3. $668 > > 4. noco: no 24v AGM mode, no temp comp > > 5. topac: no V_out data, no temp comp > > 6. V_out too high & not temp comp > > 7. noco: $229 > > 8. beeleb: no V_out data, claims unsuited to <40Ah. > > 9. AIMS: $229 > > 10. Genie $292 > > 11. promariner: no V_out data, no temp comp > > 12. 6/12v only > > 13. same as 1 > > 14. Promariner: all charge options too high V_out & well north of $200. > > 15. Promariner: no data > > 16. Beeleb again > > 17. LST: no V data, no temp comp > > 18. Adpow V_out too high, no temp comp, warns that it overcharges > > 19. V_out too high, no temp comp > > 20. Beeleb again > > 21. Renogy: DC input, no temp comp > > 22. schumacher: not a charger > > > > etc etc etc. > > > > > > NT > > Not sure what you mean by "no V_out data"no data on voltage output. Most chargers go too high for SLA. The present charger is causing problems by outputting 2x 13.7v, eveything I've seen on Amazon is worse. I suspect I'd need to either build one. I don't really want to spend the time though. Or use a bench supply, varying V_out manually between winter & summer.> Beeleb says it is suited for 2 to 200AH.They probably all are, despite the claims. But not SLA. NT
Reply by ●August 30, 20202020-08-30
On 08/29/20 03:34, Tabby wrote:> On Saturday, 29 August 2020 01:38:09 UTC+1, Chris wrote: >> On 08/28/20 23:21, Sjouke Burry wrote: >>> On 28.08.20 20:50, Chris wrote: >>>> On 08/27/20 01:30, Tabby wrote: >>>>> Cart with 2x 12v 33Ah progolf AGM lead acids. 1.5 years after fitting >>>>> new batteries the available range is down to below 10%. I'm not clear >>>>> what's gone wrong. >>>>> >>>>> The charger in use has been a cheap chinese one with 2x13.7v=27.4v >>>>> output. Single stage charging only. It has always been promptly >>>>> charged after use, and never run below 50% charge. >>>>> >>>>> I checked the battery voltages after charge, they were 13.6& 13.8v. >>>>> Charged each battery independantly to 15.2v, which took maybe half an >>>>> hour or so. No range improvement. >>>>> >>>>> When apparently flat the batteries read, offload, 12.3v& 12.8v. I >>>>> expected to see lower. >>>>> >>>>> What's going on here? >>>>> >>>>> >>>>> NT >>>> >>>> The data sheets for the better brands of the gel cell types have >>>> a graph showing expected life vs number of charge / recharge >>>> cycles. Typical design life for ups float applications can be as much >>>> as 10 years, but under regular cycling, can be<< 5 years. >>>> The deeper the discharge, the more detrimental the effect. >>>> Carts must hammer batteries pretty hard, especially if they skimp on >>>> a/h capacity to keep costs down. 38ah doesn't sound like much for >>>> what must be a 1/2 to 1hp motor, at 24 v, 1hp ~= 30 amp, then you >>>> have the much higher startup current. You get what you pay for, but >>>> Yuasa at least have different optimised types depending on type of >>>> service. >>>> >>>> I would put in bigger batteries, say 100 ah might work a lot better... >>>> >>>> Chris >>>> >>> And dont forget to buy a high quality computerized charger. >>> A cheap bad one wil sulfide the batteries in notime. >> >> >> Fully charged terminal voltage is critical as well, typically 2.3 >> volts per cell max, but the data sheets will have voltage vs >> temperature curves. Overcharging increases gassing which should >> normally be minimal. The UPS people have years of experience of >> that, as opposed to consumer electronics product, where the charger >> often looks like an afterthought... >> >> Chris > > AIUI gassing is not an option for AGM. That rules out most chargers on offer. UPSes have a terrible record of battery abuse. > > I might have to take the idea of making a charger seriously, I've never found one that does what's needed. Not that it's difficult, 240v 24v multistage AGM charging with temp comp. > > > NTFloat, or end of charge trickle is critical, as is the voltage. Normally, ups batteries are float charged at a low current continuously, but one manufacturer has patented the idea of disconnecting the float charge until the voltage reaches some lower level, then topping up, rather than a continuous float charge current. Apparently, it does improve cell lifetimes, but no direct experience here. Not too much trouble to build a charger using such ideas, perhaps with a micro to manage it all, so long as it's not commercial... Chris
Reply by ●August 30, 20202020-08-30
On 2020/08/30 3:57 p.m., Chris wrote:> On 08/29/20 03:34, Tabby wrote: >> On Saturday, 29 August 2020 01:38:09 UTC+1, Chris wrote: >>> On 08/28/20 23:21, Sjouke Burry wrote: >>>> On 28.08.20 20:50, Chris wrote: >>>>> On 08/27/20 01:30, Tabby wrote: >>>>>> Cart with 2x 12v 33Ah progolf AGM lead acids. 1.5 years after fitting >>>>>> new batteries the available range is down to below 10%. I'm not clear >>>>>> what's gone wrong. >>>>>> >>>>>> The charger in use has been a cheap chinese one with 2x13.7v=27.4v >>>>>> output. Single stage charging only. It has always been promptly >>>>>> charged after use, and never run below 50% charge. >>>>>> >>>>>> I checked the battery voltages after charge, they were 13.6& 13.8v. >>>>>> Charged each battery independantly to 15.2v, which took maybe half an >>>>>> hour or so. No range improvement. >>>>>> >>>>>> When apparently flat the batteries read, offload, 12.3v& 12.8v. I >>>>>> expected to see lower. >>>>>> >>>>>> What's going on here? >>>>>> >>>>>> >>>>>> NT >>>>> >>>>> The data sheets for the better brands of the gel cell types have >>>>> a graph showing expected life vs number of charge / recharge >>>>> cycles. Typical design life for ups float applications can be as much >>>>> as 10 years, but under regular cycling, can be<< 5 years. >>>>> The deeper the discharge, the more detrimental the effect. >>>>> Carts must hammer batteries pretty hard, especially if they skimp on >>>>> a/h capacity to keep costs down. 38ah doesn't sound like much for >>>>> what must be a 1/2 to 1hp motor, at 24 v, 1hp ~= 30 amp, then you >>>>> have the much higher startup current. You get what you pay for, but >>>>> Yuasa at least have different optimised types depending on type of >>>>> service. >>>>> >>>>> I would put in bigger batteries, say 100 ah might work a lot better... >>>>> >>>>> Chris >>>>> >>>> And dont forget to buy a high quality computerized charger. >>>> A cheap bad one wil sulfide the batteries in notime. >>> >>> >>> Fully charged terminal voltage is critical as well, typically 2.3 >>> volts per cell max, but the data sheets will have voltage vs >>> temperature curves. Overcharging increases gassing which should >>> normally be minimal. The UPS people have years of experience of >>> that, as opposed to consumer electronics product, where the charger >>> often looks like an afterthought... >>> >>> Chris >> >> AIUI gassing is not an option for AGM. That rules out most chargers on >> offer. UPSes have a terrible record of battery abuse. >> >> I might have to take the idea of making a charger seriously, I've >> never found one that does what's needed. Not that it's difficult, 240v >> 24v multistage AGM charging with temp comp. >> >> >> NT > > Float, or end of charge trickle is critical, as is the voltage. > Normally, ups batteries are float charged at a low current > continuously, but one manufacturer has patented the idea of > disconnecting the float charge until the voltage reaches some > lower level, then topping up, rather than a continuous float > charge current. Apparently, it does improve cell lifetimes, but > no direct experience here.How could that idea be patented? Seems obvious that many battery charging systems cut the power when they reach a preset voltage, then energize again when the voltage falls to a certain point. All I can see them patenting is the particular electronic process, but automobiles have been using this since alternators and generators first came out to charge the battery. I am sure the process predates that application too.> > Not too much trouble to build a charger using such ideas, > perhaps with a micro to manage it all, so long as it's not > commercial... > > ChrisJohn (I have never applied for a patent, and am unlikely ever to want to!)
Reply by ●August 30, 20202020-08-30
On 08/31/20 00:16, John Robertson wrote:> On 2020/08/30 3:57 p.m., Chris wrote: >> On 08/29/20 03:34, Tabby wrote: >>> On Saturday, 29 August 2020 01:38:09 UTC+1, Chris wrote: >>>> On 08/28/20 23:21, Sjouke Burry wrote: >>>>> On 28.08.20 20:50, Chris wrote: >>>>>> On 08/27/20 01:30, Tabby wrote: >>>>>>> Cart with 2x 12v 33Ah progolf AGM lead acids. 1.5 years after >>>>>>> fitting >>>>>>> new batteries the available range is down to below 10%. I'm not >>>>>>> clear >>>>>>> what's gone wrong. >>>>>>> >>>>>>> The charger in use has been a cheap chinese one with 2x13.7v=27.4v >>>>>>> output. Single stage charging only. It has always been promptly >>>>>>> charged after use, and never run below 50% charge. >>>>>>> >>>>>>> I checked the battery voltages after charge, they were 13.6& 13.8v. >>>>>>> Charged each battery independantly to 15.2v, which took maybe >>>>>>> half an >>>>>>> hour or so. No range improvement. >>>>>>> >>>>>>> When apparently flat the batteries read, offload, 12.3v& 12.8v. I >>>>>>> expected to see lower. >>>>>>> >>>>>>> What's going on here? >>>>>>> >>>>>>> >>>>>>> NT >>>>>> >>>>>> The data sheets for the better brands of the gel cell types have >>>>>> a graph showing expected life vs number of charge / recharge >>>>>> cycles. Typical design life for ups float applications can be as much >>>>>> as 10 years, but under regular cycling, can be<< 5 years. >>>>>> The deeper the discharge, the more detrimental the effect. >>>>>> Carts must hammer batteries pretty hard, especially if they skimp on >>>>>> a/h capacity to keep costs down. 38ah doesn't sound like much for >>>>>> what must be a 1/2 to 1hp motor, at 24 v, 1hp ~= 30 amp, then you >>>>>> have the much higher startup current. You get what you pay for, but >>>>>> Yuasa at least have different optimised types depending on type of >>>>>> service. >>>>>> >>>>>> I would put in bigger batteries, say 100 ah might work a lot >>>>>> better... >>>>>> >>>>>> Chris >>>>>> >>>>> And dont forget to buy a high quality computerized charger. >>>>> A cheap bad one wil sulfide the batteries in notime. >>>> >>>> >>>> Fully charged terminal voltage is critical as well, typically 2.3 >>>> volts per cell max, but the data sheets will have voltage vs >>>> temperature curves. Overcharging increases gassing which should >>>> normally be minimal. The UPS people have years of experience of >>>> that, as opposed to consumer electronics product, where the charger >>>> often looks like an afterthought... >>>> >>>> Chris >>> >>> AIUI gassing is not an option for AGM. That rules out most chargers >>> on offer. UPSes have a terrible record of battery abuse. >>> >>> I might have to take the idea of making a charger seriously, I've >>> never found one that does what's needed. Not that it's difficult, >>> 240v 24v multistage AGM charging with temp comp. >>> >>> >>> NT >> >> Float, or end of charge trickle is critical, as is the voltage. >> Normally, ups batteries are float charged at a low current >> continuously, but one manufacturer has patented the idea of >> disconnecting the float charge until the voltage reaches some >> lower level, then topping up, rather than a continuous float >> charge current. Apparently, it does improve cell lifetimes, but >> no direct experience here. > > How could that idea be patented? Seems obvious that many battery > charging systems cut the power when they reach a preset voltage, then > energize again when the voltage falls to a certain point. All I can see > them patenting is the particular electronic process, but automobiles > have been using this since alternators and generators first came out to > charge the battery. I am sure the process predates that application too. > >> >> Not too much trouble to build a charger using such ideas, >> perhaps with a micro to manage it all, so long as it's not >> commercial... >> >> Chris > > John (I have never applied for a patent, and am unlikely ever to want to!) >Chargers for ups systems don't cut the power, but keep a small current float, ma, to make up for losses, whereas the idea is to switch off the charge completely until the voltage has dropped to a defined lower level, then re charge to the original end of charge level. Apparently, this does improve cell life and helps to equalise the individual cell voltages, a serious problem as battery stacks age. No reference, sorry, but it may have been APC... Chris
Reply by ●August 31, 20202020-08-31
On Sunday, August 30, 2020 at 12:07:24 AM UTC-7, Tabby wrote:> On Sunday, 30 August 2020 06:54:02 UTC+1, Flyguy wrote: > > On Saturday, August 29, 2020 at 10:39:31 PM UTC-7, Tabby wrote: > > > On Saturday, 29 August 2020 18:30:03 UTC+1, Flyguy wrote: > > > > On Friday, August 28, 2020 at 7:23:27 PM UTC-7, Tabby wrote: > > > > > On Friday, 28 August 2020 01:30:59 UTC+1, Flyguy wrote: > > > > > > On Thursday, August 27, 2020 at 4:51:35 AM UTC-7, Martin Brown wrote: > > > > > > > On 27/08/2020 01:30, Tabby wrote: > > > > > > > > > > > > > Cart with 2x 12v 33Ah progolf AGM lead acids. 1.5 years after fitting new batteries the available range is down to below 10%. I'm not clear what's gone wrong. > > > > > > > > > > > > > > > > The charger in use has been a cheap chinese one with 2x13.7v=27.4v output. Single stage charging only. It has always been promptly charged after use, and never run below 50% charge. > > > > > > > > > > > > > > > > I checked the battery voltages after charge, they were 13.6 & 13.8v. Charged each battery independantly to 15.2v, which took maybe half an hour or so. No range improvement. > > > > > > > > > > > > > > > > When apparently flat the batteries read, offload, 12.3v & 12.8v. I expected to see lower. > > > > > > > > > > > > > > > > What's going on here? > > > > > > > > > > > > Battery abuse. The cheap charger has knackered both of your batteries. > > > > > > > > > > > > > > Recharging lead acid cells for maximum longevity requires some form of > > > > > > > thermal compensation of the voltage per cell during charging. eg > > > > > > > > > > > > > > https://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures > > > > > > > > > > > > > > Too much over voltage and they gas. Incorrect treatment on top up and > > > > > > > they sulphate or corrode internally either way you do damage to them. > > > > > > > The weakest cell in a chain fails first and the others then wreck it. > > > > > > > > > > > > > > -- > > > > > > > Regards, > > > > > > > Martin Brown > > > > > > > > > > > > Temperature compensation during charging is vital to maintaining the health of a battery, and they are available: > > > > > > http://www.chargingchargers.com/chargers/golf-cart/48-volt-yamaha-18.html > > > > > > You must have a REALLY old cart, being 24V. > > > > > It's 48v, 115v and $459, no use on 3 counts. The ones nearer what I'm looking for lack temp compensation. > > > > > > > > > > > > > > > NT > > > > > > > > That was exemplary of a temperature compensated charger - OF COURSE it won't work for you. There are plenty of 24V battery chargers out there: > > > > https://www.amazon.com/24-volt-battery-charger/s?k=24+volt+battery+charger > > > Of course there are. On that page: > > > > > > 1. no V_out data, no temp comp, 110v only > > > 2. adpow: too high V_out for flooded cells > > > 3. $668 > > > 4. noco: no 24v AGM mode, no temp comp > > > 5. topac: no V_out data, no temp comp > > > 6. V_out too high & not temp comp > > > 7. noco: $229 > > > 8. beeleb: no V_out data, claims unsuited to <40Ah. > > > 9. AIMS: $229 > > > 10. Genie $292 > > > 11. promariner: no V_out data, no temp comp > > > 12. 6/12v only > > > 13. same as 1 > > > 14. Promariner: all charge options too high V_out & well north of $200. > > > 15. Promariner: no data > > > 16. Beeleb again > > > 17. LST: no V data, no temp comp > > > 18. Adpow V_out too high, no temp comp, warns that it overcharges > > > 19. V_out too high, no temp comp > > > 20. Beeleb again > > > 21. Renogy: DC input, no temp comp > > > 22. schumacher: not a charger > > > > > > etc etc etc. > > > > > > > > > NT > > > > Not sure what you mean by "no V_out data" > no data on voltage output. Most chargers go too high for SLA. The present charger is causing problems by outputting 2x 13.7v, eveything I've seen on Amazon is worse. > > I suspect I'd need to either build one. I don't really want to spend the time though. Or use a bench supply, varying V_out manually between winter & summer. > > Beeleb says it is suited for 2 to 200AH. > They probably all are, despite the claims. But not SLA. > > > NTALL those chargers provided "data" on output - what DON'T they provide?
Reply by ●August 31, 20202020-08-31
On Mon, 31 Aug 2020 00:35:48 +0100, Chris <xxx.syseng.yyy@gfsys.co.uk> wrote:>On 08/31/20 00:16, John Robertson wrote: >> On 2020/08/30 3:57 p.m., Chris wrote: >>> On 08/29/20 03:34, Tabby wrote: >>>> On Saturday, 29 August 2020 01:38:09 UTC+1, Chris wrote: >>>>> On 08/28/20 23:21, Sjouke Burry wrote: >>>>>> On 28.08.20 20:50, Chris wrote: >>>>>>> On 08/27/20 01:30, Tabby wrote: >>>>>>>> Cart with 2x 12v 33Ah progolf AGM lead acids. 1.5 years after >>>>>>>> fitting >>>>>>>> new batteries the available range is down to below 10%. I'm not >>>>>>>> clear >>>>>>>> what's gone wrong. >>>>>>>> >>>>>>>> The charger in use has been a cheap chinese one with 2x13.7v=27.4v >>>>>>>> output. Single stage charging only. It has always been promptly >>>>>>>> charged after use, and never run below 50% charge. >>>>>>>> >>>>>>>> I checked the battery voltages after charge, they were 13.6& 13.8v. >>>>>>>> Charged each battery independantly to 15.2v, which took maybe >>>>>>>> half an >>>>>>>> hour or so. No range improvement. >>>>>>>> >>>>>>>> When apparently flat the batteries read, offload, 12.3v& 12.8v. I >>>>>>>> expected to see lower. >>>>>>>> >>>>>>>> What's going on here? >>>>>>>> >>>>>>>> >>>>>>>> NT >>>>>>> >>>>>>> The data sheets for the better brands of the gel cell types have >>>>>>> a graph showing expected life vs number of charge / recharge >>>>>>> cycles. Typical design life for ups float applications can be as much >>>>>>> as 10 years, but under regular cycling, can be<< 5 years. >>>>>>> The deeper the discharge, the more detrimental the effect. >>>>>>> Carts must hammer batteries pretty hard, especially if they skimp on >>>>>>> a/h capacity to keep costs down. 38ah doesn't sound like much for >>>>>>> what must be a 1/2 to 1hp motor, at 24 v, 1hp ~= 30 amp, then you >>>>>>> have the much higher startup current. You get what you pay for, but >>>>>>> Yuasa at least have different optimised types depending on type of >>>>>>> service. >>>>>>> >>>>>>> I would put in bigger batteries, say 100 ah might work a lot >>>>>>> better... >>>>>>> >>>>>>> Chris >>>>>>> >>>>>> And dont forget to buy a high quality computerized charger. >>>>>> A cheap bad one wil sulfide the batteries in notime. >>>>> >>>>> >>>>> Fully charged terminal voltage is critical as well, typically 2.3 >>>>> volts per cell max, but the data sheets will have voltage vs >>>>> temperature curves. Overcharging increases gassing which should >>>>> normally be minimal. The UPS people have years of experience of >>>>> that, as opposed to consumer electronics product, where the charger >>>>> often looks like an afterthought... >>>>> >>>>> Chris >>>> >>>> AIUI gassing is not an option for AGM. That rules out most chargers >>>> on offer. UPSes have a terrible record of battery abuse. >>>> >>>> I might have to take the idea of making a charger seriously, I've >>>> never found one that does what's needed. Not that it's difficult, >>>> 240v 24v multistage AGM charging with temp comp. >>>> >>>> >>>> NT >>> >>> Float, or end of charge trickle is critical, as is the voltage. >>> Normally, ups batteries are float charged at a low current >>> continuously, but one manufacturer has patented the idea of >>> disconnecting the float charge until the voltage reaches some >>> lower level, then topping up, rather than a continuous float >>> charge current. Apparently, it does improve cell lifetimes, but >>> no direct experience here. >> >> How could that idea be patented? Seems obvious that many battery >> charging systems cut the power when they reach a preset voltage, then >> energize again when the voltage falls to a certain point. All I can see >> them patenting is the particular electronic process, but automobiles >> have been using this since alternators and generators first came out to >> charge the battery. I am sure the process predates that application too. >> >>> >>> Not too much trouble to build a charger using such ideas, >>> perhaps with a micro to manage it all, so long as it's not >>> commercial... >>> >>> Chris >> >> John (I have never applied for a patent, and am unlikely ever to want to!) >> > >Chargers for ups systems don't cut the power, but keep a small current >float, ma, to make up for losses, whereas the idea is to switch off >the charge completely until the voltage has dropped to a defined lower >level, then re charge to the original end of charge level. Apparently, >this does improve cell life and helps to equalise the individual cell >voltages, a serious problem as battery stacks age. No reference, >sorry, but it may have been APC... > >ChrisWe were doing the Re-Float thing you just described in your last post at OutBack Power Systems in our inverter/charger almost 20 years ago. Yes, it supposedly does increase battery life if you don't need to Float all the time. It will draw as much current as necessary to hold the battery and loads, if any, at that voltage. I wonder how long ago this patent was ? I haven't heard of it being patented. But since patents are only good for 20 years now in the US, the prior art would be real close in this case. boB
