Lead Acid puzzle

On Thursday, 27 August 2020 12:51:35 UTC+1, 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.

Yup. Last time I looked for something suited to SLA AGM all the ones I saw used voltages suited to flooded cells.


NT

On 27/08/2020 01:30:42, 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?


Apply a modest load to the two batteries and then measure across them. 
0.5V is a modest difference for two matched batteries.


-- 
Mike Perkins
Video Solutions Ltd
www.videosolutions.ltd.uk

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.

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

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.

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

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

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.

1hp? Dunno but I doubt it. The onboard breaker is 30A.


NT

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

In article <d95655fb-7655-4156-a1b7-44ae2f89379co@googlegroups.com>,
Tabby  <tabbypurr@gmail.com> 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?

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.

>
>1hp? Dunno but I doubt it. The onboard breaker is 30A.
>
>
>NT

Groetjes Albert
-- 
This is the first day of the end of your life.
It may not kill you, but it does make your weaker.
If you can't beat them, too bad.
albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst