12V Lead Acid

[moveon]

i think there is something wrong with my SLA ..charged my 2nos. 8.4v lipo batteries then the alarm from the T15 says incorrect voltage input..for the past 2 nights I have been charging the SLA for 12hrs each night using the wall mount charger with variable voltage input (i set to 12v) brand is i think newstar..

the voltage is only 11.48v after charging for 12hrs last night..

do you guys think the battery is gone??

i don't have a PSU so been relying on this to charge all my batteries..without it...

please advise..

Awesome, this newstar, is it a charger or DC adaptor? Is it meant for SLA? You can get a 12V DC with 1A wall adaptor and use your tahmazo set to less then 1 amp to charge the SLA. And if this newstar you have is actually a wall DC adaptor, then check the current and power it to your T10. Can't your T10 charge SLA?

[F/S Eagle Freya]

Anatomy of SLA batteries

Most R/C chargers are now capable of charging Sealed Lead Acid batteries. Some of the brands I know are: Schulze, Tritron, Tamazo T10 or T15. The only thing you must know when charging SLA batteries is that this type of battery cannot be charged at more than 2Amps so when you set your chargers, be sure not to go beyond 2amps. The lower the charging current the better for the battery but of course charging time will be more.

As the name implies, “Sealed” lead acid, actually these batteries are not totally sealed. There are small openings on each cell. On top of each cell is valve regulator which composes of a rubber that regulates the pressure inside the battery. During charging, gasses emits form the positive and negative plates of the battery causing an increase in pressure inside each cell. The more current you pump in, the more gasses it will be produced and the more pressure it will accumulate in each cell. The valve on top of each cell will allow the escape of this excess pressure which is passed through a very little opening on the top cover of the battery. Should there be clogging to the lines of this tiny openings or the pressure produced inside is more than what this openings can pass through, then there is a possibility of explosion. This is basically what happens when one of the cell of your SLA battery poooofs. Please refer to the link below to have a better understanding about the anatomy of SLA batteries.

http://www.mycableshop.com/techarticles/technicaldetailsofSLA.htm

In short, in order to get rid of this problem, do not exceed 2amps when charging your battery. Actually 2amps is the maximum but a lower value is recommended. If you have the chargers mentioned above all you need is to get a good PSU and this should solve your problem. I am recommending my PSU for this purpose. Please refer to link below.

http://www.daddyhobby.com/forum/showthread.php?t=8699

[awesome]

Awesome, this newstar, is it a charger or DC adaptor? Is it meant for SLA? You can get a 12V DC with 1A wall adaptor and use your tahmazo set to less then 1 amp to charge the SLA. And if this newstar you have is actually a wall DC adaptor, then check the current and power it to your T10. Can't your T10 charge SLA?

hi chai..thanks for quick reply..correction: mine is T15

hope i don't confuse myself:

1. the newstar has a switch for charger and adaptor. i only use the charger mode to charge my SLA at 12V. There is an option for 6v, 9v, 12v and 15v output (i think). I use 12v cos the SLA is 12v. i had no problem charging my SLA this way earlier leh. At one time, it even read 15V...then now charge and charge but gives only 11.5v..

2. I tried using the adaptor mode to power the T15 for my lipo last time but switched to adaptor mode (but maintaining 12v output like for charger mode). The error message said incorrect inout voltage so i din go any further. I din try using this newstar to charge my SLA hence. Also, i heard that this kind of charger/adaptor with varying voltage output does not give contant current output hence the T15 cannot accept.

3. I was told you need an adaptor with at least 3A output to charge lipos so got this newstar but it din really work. I oso not very familiar with this T15 so not very sure how to set to less than 1 amp..

[moveon]

hi chai..thanks for quick reply..correction: mine is T15

hope i don't confuse myself:

1. the newstar has a switch for charger and adaptor. i only use the charger mode to charge my SLA at 12V. There is an option for 6v, 9v, 12v and 15v output (i think). I use 12v cos the SLA is 12v. i had no problem charging my SLA this way earlier leh. At one time, it even read 15V...then now charge and charge but gives only 11.5v..

2. I tried using the adaptor mode to power the T15 for my lipo last time but switched to adaptor mode (but maintaining 12v output like for charger mode). The error message said incorrect inout voltage so i din go any further. I din try using this newstar to charge my SLA hence. Also, i heard that this kind of charger/adaptor with varying voltage output does not give contant current output hence the T15 cannot accept.

3. I was told you need an adaptor with at least 3A output to charge lipos so got this newstar but it din really work. I oso not very familiar with this T15 so not very sure how to set to less than 1 amp..

OK, for input voltage error on T15 is because when you set the adaptor to 12V, the output from the adaptor is higher then expected by the T15. Reason is because this is unregulated power adaptor. The final voltage will depend very much on the load.......This charger mode does not charge SLA correctly. The isn't any floating charge at the end of the full charge cycle. It's better to get a regulated DC power supply for your T15 and make use of the full charging capabilties of the T15. Your SLA life has run out. For SLA, it must be stored with full charge........I hope this info helps...............

[awesome]

Most R/C chargers are now capable of charging Sealed Lead Acid batteries. Some of the brands I know are: Schulze, Tritron, Tamazo T10 or T15. The only thing you must know when charging SLA batteries is that this type of battery cannot be charged at more than 2Amps so when you set your chargers, be sure not to go beyond 2amps. The lower the charging current the better for the battery but of course charging time will be more.

huh? cannot charge at more than 2amps?? could this be the reason for the early demise?? i don't use my T15 to charge my SLA..only using the newstar, which gives 3A output..

If you have the chargers mentioned above all you need is to get a good PSU and this should solve your problem. I am recommending my PSU for this purpose.

thanks....how much are you charging?? Am contemplating of getting another SLA but scare kenna same problem again

[awesome]

OK, for input voltage error on T15 is because when you set the adaptor to 12V, the output from the adaptor is higher then expected by the T15. Reason is because this is unregulated power adaptor. The final voltage will depend very much on the load.......This charger mode does not charge SLA correctly. The isn't any floating charge at the end of the full charge cycle. It's better to get a regulated DC power supply for your T15 and make use of the full charging capabilties of the T15. Your SLA life has run out. For SLA, it must be stored with full charge........I hope this info helps...............

thanks again chai..need to spend money liao lor..kekeke

so if the load is 8.4v lipo..i should set lower..say 6v?

so wat is floating charge?

Also, for the SLA to stay full charge..do you mean to constantly keep the DC power on?? Will get overheated or not??

Your info certainly help for someone like me..so glad to have learn something today..

cheers to you and F/S Eagle Freya!!!!

[moveon]

thanks again chai..need to spend money liao lor..kekeke

so if the load is 8.4v lipo..i should set lower..say 6v?

so wat is floating charge?

Also, for the SLA to stay full charge..do you mean to constantly keep the DC power on?? Will get overheated or not??

Your info certainly help for someone like me..so glad to have learn something today..

cheers to you and F/S Eagle Freya!!!!

For 8.4 lipo, you need to set T15 to 2cell lipo(so T15 takes care of the chraging voltage) and charge current set to 0.7C or 1C (don't go above 1C)

SLA initial charge at bulk, and approaching full charge, a small current(float charge) is supplied to the SLA from the charger. The charger continue to charge the SLA with floating charge current, thus SLA will stay fully charge and will not over charge or overheating. But your charger must be capable of float charging. Not all wall charger is capable of float charging. All SLA rated charger has float charge. So, only use charger designed for charging SLA.....

[awesome]

moveon, just a feedback -

tried charging my 8.4v 1300mah GWS 2s lipo last night using the newstar in adaptor mode. I had to set the output to 6v in order to charge. Current is set to 800ma on the T15.

During charging, the current fluctuates, as shown in the T15, at +/- 10% during the initial stage and at final stage.

Before reaching peak, the voltage on the lipo is 8.398 or 8.401v with about 0.15ma to go. At peak, ie, full charge, the voltage drops to 8.23v

The adaptor gets a little warm during charging.

Think i am more confident liao ..much thanks to you....

[X34]

Our chargers require a constant power source, adaptors cannot deliver that kind of supply, therefore, a good PSU is very important. The cheapest stable PSU is a converted PC power supply. Lots of thread in this forum discussed about the conversion.

Wall adaptor SLA charger are battery killer. Avoid using them for maintaining battery. The charging of SLA was discussed on the earlier post of this thread. Secondly, if the adaptor is not diode protected, it may discharge the SLA if the voltage is lower than the SLA.

Any of our hobby charger like Triton, Orbit, Schulze, Tahmazo etc.. with lead acid charging program will be able to maintain the SLA better than any adaptor or non-program controlled chargers. And it doesn't heat up the battery.

My suggestion is to invest in a PC PSU and use your nice chargers to charge the SLA.

I find it difficult to accept the max charging amp of SLA to be 2 amps. Lots of cars uses SLA and are charge at 16 amps to 50 amps. I have been charging my 27 AH SLA at 5 amps and the batt is 5 years old and still going strong. The only reason for 5 amps is b'cos the charger max out.

[awesome]

Our chargers require a constant power source, adaptors cannot deliver that kind of supply, therefore, a good PSU is very important. The cheapest stable PSU is a converted PC power supply. Lots of thread in this forum discussed about the conversion.

Wall adaptor SLA charger are battery killer. Avoid using them for maintaining battery. The charging of SLA was discussed on the earlier post of this thread. Secondly, if the adaptor is not diode protected, it may discharge the SLA if the voltage is lower than the SLA.

Any of our hobby charger like Triton, Orbit, Schulze, Tahmazo etc.. with lead acid charging program will be able to maintain the SLA better than any adaptor or non-program controlled chargers. And it doesn't heat up the battery.

My suggestion is to invest in a PC PSU and use your nice chargers to charge the SLA.

I find it difficult to accept the max charging amp of SLA to be 2 amps. Lots of cars uses SLA and are charge at 16 amps to 50 amps. I have been charging my 27 AH SLA at 5 amps and the batt is 5 years old and still going strong. The only reason for 5 amps is b'cos the charger max out.

thanks X34, your words has given me some encouragement..will definitely consider getting a PSU...hee

I have been wondering...how do you measure the amp of the SLA? I used a multi-meter on a lipo before but the multi-meter wires get very hot..so dare not try further..i stick to using the voltmeter feature only..:P

also, how many different types of SLA are there and which is recommended for hobbies? dun want to go Sim Lim and end up buying the wrong one the one i'm currently using is from rotor and cost me $33 which i think its damn ex..

[X34]

I have been wondering...how do you measure the amp of the SLA? I used a multi-meter on a lipo before but the multi-meter wires get very hot..so dare not try further..i stick to using the voltmeter feature only..:P..

Better to use clamp amp meter.

also, how many different types of SLA are there and which is recommended for hobbies? dun want to go Sim Lim and end up buying the wrong one the one i'm currently using is from rotor and cost me $33 which i think its damn ex..

Depends on what u need it for, for starter 7 AH is plenty. To charge motor batt as big as u can transport. Buy from SLT, Hitachi, Yuasa $16 to $26 for 7 amp.

[awesome]

thanks X34..