Mobility Scooter 24V Battery Charger annoyance...

ThisIsWeird

The good news is that I worked out why mil's 'kooter wouldn't hold a charge, and the power bars would drop like the flies in her 8mph wake - the 12V charger was wired across one of the two 12V batteries, and the batteries were in series. It was a 24V system.

So, we need a 24V charger. You'd think this would be simple...

The supplied 12V jobbie (this was with a good, second-hand scooter* from a relative) was a CTEK - MSX10 which, by all accounts, is a beaut, and costs around £150-odd. It has a series of LED lights to indicate charging stages, from 'testing', to 'desulphation', to 'bulk', to 'absorption', to gawdknowswhat. It seems to be good at reconditioning the battery and keeping it tip-top.

So, we need a 24V equivalent - or near as - that doesn't cost stupid-money.

Any ideas?

This is the battery (there are two). It's 75Ah, and seems to be happy with an initial charge current of 22.5A or less (that sounds high, but hey).

My Qs, please, are;

1) Does the 'power' of the battery charger actually matter? Some folk have said, "Ooh, you need an 8A charger for these batteries!", but won't a 4A charger do the job just as well, but take twice as long?

2) Is the 'desulphation' feature as effective and useful as it sounds? Do these types of batteries - AGM - need this, especially when new?

3) Any recommendations for a battery charger that does a good job, ideally with these best features, but isn't silly money?

Thanks :-)

*TGA Breeze S3

forgotmyname

The only reason I can think of a smaller charger not being sutable assuming the voltage is correct is that the charger has a duty
cycle where it was not designed to run for more than ## hours and charging a larger battery will go beyond its duty cycle.

I have stuck small batteries on larger engined cars in emergencies and everything was all good, the only issue is that if the
car did not start quickly the battery would not last long cranking a larger engine. On the plus side is that it will reach its full
charge a lot faster the same applies to chargers.

As you have a 12v charger I would use that on each battery and cycle them a couple of times before using.

Rodders53

Make and model of Scooter... Then Google for a replacement 24V charger...  They are all made in China for the scooter manufacturers.

Almost all scooter chargers have been smart type for the many years we have had mobility scooters.

Likely the scooter battery box may need rewiring to suit the correct 24V charger if it was modified to take the 12V charger?
Very likely at least one of the batteries is damaged irreversibly from the deep discharge... But the CTEK may revive it... As suggested charge each battery individually before reinstalling in scooter.

Be prepared to replace both as a pair!  Lucas and Yuasa are my favourite brands for longevity of repeated charging.

4A charger takes around 4 hours or so with 22Ah batteries when they have been used a fair bit/distance (but never more than 50% discharge) so you may see why 8A is recommended for the bigger ones you have.  Note the 4 or 8 Amp rate is only used during one stage of the multi rate smart charge process.

ThisIsWeird

Thank you.
That makes sense, forgotmyname - a smaller charger may need to run for too long, and struggle.
The 12V charging cables had been wired directly to one battery only - I suspect the previous owner thought they were in parallel, and did this if the original charger became faulty. Brand new batteries were fitted before sale. Yes, I moved the cables to the second battery, and gave that one a good charge too - batteries are spot on, and scooter is going well
Thanks, Rodders - yes, there's no shortage of chargers, but struggling to choose. I'd like it to have the important features, whilst not being as stupidly priced as £100+.
The scooter has a 24V charging socket built in, and a continuity test suggested it was connected to the batteries correctly, so I just need the charger.
As you say, they don't charge at max rate all the time in any case, and the charging duration isn't an issue - it would just be left on overnight. 
Any known model fit the bill?
Cheers.

ThisIsWeird

SLK Power sell their own battery chargers, so I might play safe and suggest that to mil.

One final Q, please - is the desulphation feature worthwhile?

Thanks.

Mildly_Miffed

ThisIsWeird said:

The good news is that I worked out why mil's 'kooter wouldn't hold a charge, and the power bars would drop like the flies in her 8mph wake - the 12V charger was wired across one of the two 12V batteries, and the batteries were in series. It was a 24V system.

So, we need a 24V charger. You'd think this would be simple...

The supplied 12V jobbie (this was with a good, second-hand scooter* from a relative) was a CTEK - MSX10 which, by all accounts, is a beaut, and costs around £150-odd. It has a series of LED lights to indicate charging stages, from 'testing', to 'desulphation', to 'bulk', to 'absorption', to gawdknowswhat. It seems to be good at reconditioning the battery and keeping it tip-top.

So, we need a 24V equivalent - or near as - that doesn't cost stupid-money.

Any ideas?

This is the battery (there are two). It's 75Ah, and seems to be happy with an initial charge current of 22.5A or less (that sounds high, but hey).

My Qs, please, are;

1) Does the 'power' of the battery charger actually matter? Some folk have said, "Ooh, you need an 8A charger for these batteries!", but won't a 4A charger do the job just as well, but take twice as long?

2) Is the 'desulphation' feature as effective and useful as it sounds? Do these types of batteries - AGM - need this, especially when new?

3) Any recommendations for a battery charger that does a good job, ideally with these best features, but isn't silly money?

Thanks :-)

*TGA Breeze S3

Yes, CTek are excellent chargers.

No, it's purely a question of charge time. 2 x 75Ah chargers, and you're not taking them below about 50% - hopefully the buggy manages that - so a 10A charger will easily recharge overnight.


AGM batteries are definitely prone to sulphation, so a charger that has a setting for that is a good plan.

CTek do a 24v charger, but it ain't cheap...
https://www.amazon.co.uk/CTEK-MXT-14-Battery-Charger/dp/B0050HMCIQ

How about something like...?
https://www.tayna.co.uk/battery-chargers/numax/?ordering=&A-17=24
Does the buggy have this type of charge connector?

Vitor

If MIL is receiving certain benefits charities such as Turn2us, Disability Rights UK, and The Mobility Trust may be able to help you access funds for a new charger.

Even if you buy privately, you should be able to get VAT relief  - 24V Victron Impulse II Mobility Charger (mobilitysmart.co.uk)

returnofghandi

Ideally 8amp charger for 75ah batteries:

https://discountscooters.co.uk/products/8-amp-battery-charger-with-reverse-polarity

or

https://www.sheffieldmobility.co.uk/product-page/8-amp-battery-charger-for-tga-breeze 

or

https://www.firstchoicemobility.com/parts/scooter-maintenance/battery-chargers/6-amp-chargers-to-8-amp-chargers/reverse-polarity-oem-tga-breeze-battery-charger.html

Heedtheadvice

I would also suggest Tayna as a good source but for check around!

Mildly_Miff ed said:

ThisIsWeird said:

The good news is that I worked out why mil's 'kooter wouldn't hold a charge, and the power bars would drop like the flies in her 8mph wake - the 12V charger was wired across one of the two 12V batteries, and the batteries were in series. It was a 24V system.

So, we need a 24V charger. You'd think this would be simple...

The supplied 12V jobbie (this was with a good, second-hand scooter* from a relative) was a CTEK - MSX10 which, by all accounts, is a beaut, and costs around £150-odd. It has a series of LED lights to indicate charging stages, from 'testing', to 'desulphation', to 'bulk', to 'absorption', to gawdknowswhat. It seems to be good at reconditioning the battery and keeping it tip-top.

So, we need a 24V equivalent - or near as - that doesn't cost stupid-money.

Any ideas?

This is the battery (there are two). It's 75Ah, and seems to be happy with an initial charge current of 22.5A or less (that sounds high, but hey).

My Qs, please, are;

1) Does the 'power' of the battery charger actually matter? Some folk have said, "Ooh, you need an 8A charger for these batteries!", but won't a 4A charger do the job just as well, but take twice as long?

2) Is the 'desulphation' feature as effective and useful as it sounds? Do these types of batteries - AGM - need this, especially when new?

3) Any recommendations for a battery charger that does a good job, ideally with these best features, but isn't silly money?

Thanks :-)

*TGA Breeze S3

Yes, CTek are excellent chargers.

No, it's purely a question of charge time. 2 x 75Ah chargers, and you're not taking them below about 50% - hopefully the buggy manages that - so a 10A charger will easily recharge overnight.


AGM batteries are definitely prone to sulphation, so a charger that has a setting for that is a good plan.

CTek do a 24v charger, but it ain't cheap...
https://www.amazon.co.uk/CTEK-MXT-14-Battery-Charger/dp/B0050HMCIQ

How about something like...?
https://www.tayna.co.uk/battery-chargers/numax/?ordering=&A-17=24
Does the buggy have this type of charge connector?

ThisIsWeird

Thank you everyone - that's brilliant stuff

Interesting about the seemingly low minimum discharge voltage, MildlyMiffed - I'd hope the Scooter's LCD display would flash it's remaining one bar level well before the damaging 40% stage is reached? What is the best recharging policy - to let it fall to, say, 2 pips, or to recharge regularly at, say, half? (bad for Lithiums, I belive, but no idea about AGM)?

Yes, it's the three-pin plug shown. And, yes, the 24V CTEK nearly caused apoplexy.

Tayna's (good co) Numax doesn't make it clear what display it has - the pdf suggests LCD, but I doubt it. Also, does it have desuplh, do you know? https://www.tayna.co.uk/battery-chargers/numax/mobility-24v-7a/

ThisIsWeird

Thanks for the Vitron suggestion, Vitor - do you know if that one has desulph? 

She doesn't receive any benefits, and affording this ain't an issue, but I'm still reluctant to recommend a silly-priced model, if a better value one does the same.

Cheers.