Model Boat Mayhem - Forum

Technical, Techniques, Hints, and Tips => Batteries & Chargers => Topic started by: TheLongBuild on May 13, 2019, 01:30:31 PM

Title: SLA battery not lasting for long.
Post by: TheLongBuild on May 13, 2019, 01:30:31 PM
Hi
If you have a SLA battery and you let it run flat would this reduce the amount of time it would then last once recharged. ?


Larry
Title: Re: SLA battery not lasting for long.
Post by: Jerry C on May 13, 2019, 02:00:59 PM
(https://www.modelboatmayhemimages.co.uk/images/2019/05/13/84CCC398-DE75-4AC6-A904-13D119C8E826.jpg) (https://www.modelboatmayhemimages.co.uk/image/JAzmv)


Yes it will seriously degrade the number of cycles available. Never discharge an SLA battery more than 50% capacity. That equates to 12.1 volts rested with no loads or charging over the last 20 mins.
For AGM Batteries itís 12.05 volts.
Jerry.
Title: Re: SLA battery not lasting for long.
Post by: john44 on May 13, 2019, 02:17:07 PM
Hi as Jerry says, pb ,or gell cells, whatever you want to call them do degenerate if not kept
At a reasonable rate of charge, shorting through the cells to give a reduced voltage.
If a low reading is found some chargers may not recognise the battery and refuse to charge it.
So then becomes ballast or scrap I'm afraid.


John
Title: Re: SLA battery not lasting for long.
Post by: malcolmfrary on May 13, 2019, 03:21:01 PM
Lead acid batteries work by depositing a chemical layer on the plates during charging, and changing it during discharge.  Back when I was doing that kind of thing for C&G in tech, I could have spouted formulas with fair acuracy, but not following the exam.  Because the powers of evil have so decided, the re-deposition does not always match and put stuff back where it was before, so it grows weak bits.  Putting them to heavy use causes the plates to either warp or try to, which doesn't help, either.
Letting a battery self discharge lets subtly different chemical reactions take place, and while careful recharging "might" put life back in there, the plating will not be the same.  A factory rebuild is needed.  The good bit about lead batteries is that they are almost totally recycleable, almost everythng in them can be re-used.
Title: Re: SLA battery not lasting for long.
Post by: CGAux26 on May 13, 2019, 03:58:45 PM
I have used SLA's for 10 years.  Seldom go below 70% charge.  I come back from the pond and immediately put the batteries on charge and let them charge a day or two (0.5 amp charger).  They seem to hold at least 95% charge over months of non-use.


Never get rid of SLA's.  Even DEAD they make great clamping weights.   :-))
Title: Re: SLA battery not lasting for long.
Post by: CGAux26 on May 13, 2019, 04:11:44 PM
   >>:-( <*< <*<
I have been trying for 15 minutes to finish my post to this topic.  Picture too big.  Won't save picture and complete response.  Here goes AGAIN posting the picture.
Title: Re: SLA battery not lasting for long.
Post by: TheLongBuild on May 13, 2019, 06:20:42 PM

Thanks all.
Battery not actually being used for a model but a Water Polo Shot clock, I believe the battery was allowed to fully run down and then left for some time, now only lasts 40 minutes..   %% %% 



Title: Re: SLA battery not lasting for long.
Post by: Jerry C on May 13, 2019, 07:04:57 PM
Itís defo Donald ducked then!
Jerry.
Title: Re: SLA battery not lasting for long.
Post by: justboatonic on May 27, 2019, 04:05:56 PM
If you have small SLA 12v batteries and do not want this to happen, consider buying a Ctek XS0.8 https://www.ctek.com/products/vehicle/xs-0-8or other similar battery conditioning charger.
This will keep your SLA battery including that in your car in top condition. It wont charge a car sized battery from flat but is ideal where the battery is left for long periods of time.
Title: Re: SLA battery not lasting for long.
Post by: SteamboatPhil on May 28, 2019, 07:21:50 PM
SLA's should always be left charged, and has been said yours is most probably well not very well / dead.
Have a look at "component shop" or  sales@batteryworldshop.com


Either will be able to help
Title: Re: SLA battery not lasting for long.
Post by: RST on May 28, 2019, 07:27:51 PM
Has the car charger world progressed. I always heeded the warnings about not mixing anything car charger like with small SLA's.  I've always used my old Robbe multilader charger. I'd agree though these days component shop for cheap dedicated chargers.
Title: Re: SLA battery not lasting for long.
Post by: grendel on May 29, 2019, 04:56:35 AM
I use a smart charger from lidl, it detects if it is a bike or car battery and if its 6v or 12 and charges accordingly.