I have now taken the batteries out of the chair the voltage barely detectable have connected them up to the charger to see if some life can be brought back to them but I do not expect I will get very far.
Checked charger output at about 0.75 amps and voltage from open circuit only fell from 25.3 to 24 volts. Trying to workout circuit diagram of chair charging system.
I have now taken the batteries out of the chair the voltage barely detectable have connected them up to the charger to see if some life can be brought back to them but I do not expect I will get very far.
Checked charger output at about 0.75 amps and voltage from open circuit only fell from 25.3 to 24 volts. Trying to workout circuit diagram of chair charging system.
Just checked eBay $10.99 shipped! Also looked at battle and see the series I mean to use are available in 3 sizes with just an increase in width. Don't know if more than the 7ah is needed but the option is there. Thanx for that tidbit! GJ
Just checked eBay $10.99 shipped! Also looked at battle and see the series I mean to use are available in 3 sizes with just an increase in width. Don't know if more than the 7ah is needed but the option is there. Thanx for that tidbit! GJ
My new 24 volt charger arrived to day from e bay, cost with delivery £ 10.69. This is with a very nicely made connector that I will remove. Output voltage unloaded 25.4 which would seem about right for two 12 volt batteries in series at indoor temperature.
Other for sale on e bay nominally for stair lifts ranged from £ 199 down ! which further confirms my belief that a lot of the infirm are being ripped off.
When I have time and the energy, next to get the old batteries out and see what state they are in.
My new 24 volt charger arrived to day from e bay, cost with delivery £ 10.69. This is with a very nicely made connector that I will remove. Output voltage unloaded 25.4 which would seem about right for two 12 volt batteries in series at indoor temperature.
Other for sale on e bay nominally for stair lifts ranged from £ 199 down ! which further confirms my belief that a lot of the infirm are being ripped off.
When I have time and the energy, next to get the old batteries out and see what state they are in.
Hi piers
You are a bit like me have been a member for a long time with big gaps in our building. I have two on the go very slowly at the present time, but have a lot of other things to do.
Best of luck with your re start and this site and its members are a great source of information.
nasraf
You are a bit like me have been a member for a long time with big gaps in our building. I have two on the go very slowly at the present time, but have a lot of other things to do.
Best of luck with your re start and this site and its members are a great source of information.
nasraf
Hi Griss
Thanks for the response I will have a look on Aliexpress I am already a convert.
Thanks for the response I will have a look on Aliexpress I am already a convert.
Great post Nas. I was a mechanic at the U of Minnesota for 34 yrs. Among my myriad of duties was maintaining battery powered 3 wheel carts for the miles of steam tunnels 100 feet below the campus. Every week I'd top up the cells of the size 27 car batts. There were a pair of 12v chargers for each cart. Battery attrition was high due to the heat-someplaces 140F. I'm a new oldie here and am moving forward on a ship whose hull was built 10 yrs back. Have no experience in RC so a new learning subject. As with any field you web folks are the goldmine of info for us nubes. Thankyou,GuzziJohn😉
Great post Nas. I was a mechanic at the U of Minnesota for 34 yrs. Among my myriad of duties was maintaining battery powered 3 wheel carts for the miles of steam tunnels 100 feet below the campus. Every week I'd top up the cells of the size 27 car batts. There were a pair of 12v chargers for each cart. Battery attrition was high due to the heat-someplaces 140F. I'm a new oldie here and am moving forward on a ship whose hull was built 10 yrs back. Have no experience in RC so a new learning subject. As with any field you web folks are the goldmine of info for us nubes. Thankyou,GuzziJohn😉
Hi Roycv
It is not possible to add a third terminal, as the connections are made with effectively a pair of brushes at the top and bottom of the rail. So I am afraid that they will have to be charged in series.
Thanks for the suggestion.
It is not possible to add a third terminal, as the connections are made with effectively a pair of brushes at the top and bottom of the rail. So I am afraid that they will have to be charged in series.
Thanks for the suggestion.
The chinks produce intelligent chargers at the right money how good they are is unknown i.e. possible fire hazard.Use of intelligent charger will cure your overcharge problems.
The chinks produce intelligent chargers at the right money how good they are is unknown i.e. possible fire hazard.Use of intelligent charger will cure your overcharge problems.
Hi they must come out for replacement? I would get to them and put an extra wire between them i.e. centre tapped. Bringing it out so it is near the other terminals. This way you can charge them as 12 volt batteries.
If one of them goes down you will never know otherwise!
I would not charge them as 24 volts as there must be chargers around but 12 volt ones are more plentiful.
Roy
Hi they must come out for replacement? I would get to them and put an extra wire between them i.e. centre tapped. Bringing it out so it is near the other terminals. This way you can charge them as 12 volt batteries.
If one of them goes down you will never know otherwise!
I would not charge them as 24 volts as there must be chargers around but 12 volt ones are more plentiful.
Thanks Roy
I should have explained the set up a bit more.
The batteries are 2 AH and are enclosed in the seat structure so it is only possible to get to the terminals of two batteries in series, actually you can only get to the wiring of the sliding contacts on the chair rail. The chair parks either at the top or bottom of its rail and then is on continuous charge.
From the info you supplied it would be probably be best to get a constant current charger with a nominal 24 volt output and run it at something like half an amp, I do not know if there are any relatively cheap chargers capable of doing this on the market ?
The batteries are 2 AH and are enclosed in the seat structure so it is only possible to get to the terminals of two batteries in series, actually you can only get to the wiring of the sliding contacts on the chair rail. The chair parks either at the top or bottom of its rail and then is on continuous charge.
From the info you supplied it would be probably be best to get a constant current charger with a nominal 24 volt output and run it at something like half an amp, I do not know if there are any relatively cheap chargers capable of doing this on the market ?
Hi do not worry about temperatures it does not vary enough to be a problem Trickle charging rate is one tenth the capacity of the battery, so 700 mA. You have to compensate for the inefficiency of the battery and so 10 hours times 140% comes out at 14 hours charging time.
Forgive me but I am not clear on whether you are charging a 7Ah or a 2Ah, battery.
As you know when charging SLA batteries they use taper charging so start with a 14/15 volt voltage from the charger with a max current limit of say 2 amps and as the battery voltage increases so the charge voltage decreases.
If you want to take the batteries out of the mechanism and charge them separately then Howes do a 12 volt SLA charger which you may want with crocodile clips on, to connect to the battery and just leave it until the green light shows.
They are very helpful on the phone just tell them you want an intelligent charger for a 12 volt 7 amp hour SLA battery. The intelligent bit is that it reverts to a trickle charge (sometimes called a float charge) when the charge is finished.
Good luck
Roy
Hi do not worry about temperatures it does not vary enough to be a problem Trickle charging rate is one tenth the capacity of the battery, so 700 mA. You have to compensate for the inefficiency of the battery and so 10 hours times 140% comes out at 14 hours charging time.
Forgive me but I am not clear on whether you are charging a 7Ah or a 2Ah, battery.
As you know when charging SLA batteries they use taper charging so start with a 14/15 volt voltage from the charger with a max current limit of say 2 amps and as the battery voltage increases so the charge voltage decreases.
If you want to take the batteries out of the mechanism and charge them separately then Howes do a 12 volt SLA charger which you may want with crocodile clips on, to connect to the battery and just leave it until the green light shows.
They are very helpful on the phone just tell them you want an intelligent charger for a 12 volt 7 amp hour SLA battery. The intelligent bit is that it reverts to a trickle charge (sometimes called a float charge) when the charge is finished.
Modern chargers will return to trickle charge when charged or you can purchase a12 volt trickle charger obviously idont know the physical size of your batteries but i recently purchased a 12v 7Ah battery in sale for about £11 from Howes Models.
Modern chargers will return to trickle charge when charged or you can purchase a12 volt trickle charger obviously idont know the physical size of your batteries but i recently purchased a 12v 7Ah battery in sale for about £11 from Howes Models.
This is not specifically a model boat problem but I expect those who use this site know more about charging small batteries than anyone else.
I have a battery powered chair lift that I had fitted to aid my wife through her illness before she died and as I am getting on a bit, I have kept it in case I need it and you getting nothing for them if you put them on the market.
Whilst she was still ill the chair failed to operate about six months after I purchased it and I looked into the problem and found that one of the two 12 volt 7Ah sealed L.A.batteries had failed. At the time a just bought a new one and got the chair going again. After she passed away I left the chair and when I checked a few months later it failed to operate again, but as I had other things to do I just left it, but now want to make it operational.
First thing I did was to see if I could get a circuit diagram of the device, but I think these are closely guarded secrets, so that the rip off companies who sell them to a very vulnerable public, can force them into taking out very expensive maintenance contracts.
I know a reasonable amount about electrical devices so decided to poke about and see what I could do without a full electrical circuit. I also had a look at E Bay to see what was available there in terms of spares. I was interested to find for mine there were two battery chargers available one with an output of 33 volts dc and another with an output of 24 volts dc.. I checked mine and it was one of the 33 volt sort, I think the latter version to be fitted initially to ensure, after a relatively short period you would need the assistance of their expensive maintenance man and a subsequent service contract. As when I worked for money, I was involved in the design of i.c. engined generator sets for guided weapon systems so I had had some experience of charging L.A. batteries over large temperature ranges from minus 30 to plus 52 centigrade. Due to this large range we produced a charger that varied its output potential dependent on the battery temperature.
Its a long time ago that I was involved in that and do not have access to the ideal charging potentials. However with access to a whole heap of experts, what do you think is the ideal continuous charging potential, at say 20 degrees centigrade, for a 12 volt 2 AH sealed lead acid battery. Then after I buy new batteries, as I am sure that what is wrong with the chair at present is that the batteries have died due to continuous over charging, make a charger that will give me a good battery life.
This is not specifically a model boat problem but I expect those who use this site know more about charging small batteries than anyone else.
I have a battery powered chair lift that I had fitted to aid my wife through her illness before she died and as I am getting on a bit, I have kept it in case I need it and you getting nothing for them if you put them on the market.
Whilst she was still ill the chair failed to operate about six months after I purchased it and I looked into the problem and found that one of the two 12 volt 7Ah sealed L.A.batteries had failed. At the time a just bought a new one and got the chair going again. After she passed away I left the chair and when I checked a few months later it failed to operate again, but as I had other things to do I just left it, but now want to make it operational.
First thing I did was to see if I could get a circuit diagram of the device, but I think these are closely guarded secrets, so that the rip off companies who sell them to a very vulnerable public, can force them into taking out very expensive maintenance contracts.
I know a reasonable amount about electrical devices so decided to poke about and see what I could do without a full electrical circuit. I also had a look at E Bay to see what was available there in terms of spares. I was interested to find for mine there were two battery chargers available one with an output of 33 volts dc and another with an output of 24 volts dc.. I checked mine and it was one of the 33 volt sort, I think the latter version to be fitted initially to ensure, after a relatively short period you would need the assistance of their expensive maintenance man and a subsequent service contract. As when I worked for money, I was involved in the design of i.c. engined generator sets for guided weapon systems so I had had some experience of charging L.A. batteries over large temperature ranges from minus 30 to plus 52 centigrade. Due to this large range we produced a charger that varied its output potential dependent on the battery temperature.
Its a long time ago that I was involved in that and do not have access to the ideal charging potentials. However with access to a whole heap of experts, what do you think is the ideal continuous charging potential, at say 20 degrees centigrade, for a 12 volt 2 AH sealed lead acid battery. Then after I buy new batteries, as I am sure that what is wrong with the chair at present is that the batteries have died due to continuous over charging, make a charger that will give me a good battery life.
