leisure battery advice

[Astroblagger]

Hello iv got a 50A/hour leisure battery, im just wandering if totally draining it and recharging it will be ok, reason being iv had power issues to my camera even when my charger says its fully charged,

Also how long do you think is normal for charging it after use my charger says its fully charged after 2-3 hours after iv used it for 5-6 hours after an imaging session. Just seems very quick to me?

[Scott]

I really don't know about the draining idea..I have a charger that will "restore" the battery (for lack of a better word). I do this about every 3rd charge. What makes me wonder if it's the battery or not is that you can run a mount etc for 5-6 hrs...surely they would be more demanding than the canon.

Sorry, just something else for you to ponder . maybe check the camera with the supplied battery?

[michael.h.f.wilkinson]

Totally draining lead acid batteries is not a good idea. On my power tank the charging indicator shows the "ready to use" or "fully charged" LED glowing green while the "charging" LED is still red. I always allow it to charge until the "charging" LED turns off.

[leelee970]

Don't "Fully" discharge a lead acid battery, you'll cause irreversible damage. You should put it on trickle charge overnight.

 

How old is the battery ???

Lee

[Astroblagger]

its only about 1 1/2 to 2 years old its always kept inside, i always charge it the next day after usage. maybe im just not charging it long enough

im getting 12V with a multimeter across it after charge i think its should read between 13.5 and 14 volts when fully charged.

[perfrej]

Correct. NEVER discharge a lead-acid battery. Standard "car" batteries can not tolerate discharge below about 11V, gel batteries are slightly more tolerant and AGM ones can be fully discharged without damage.

If you buy a battery, bring a voltmeter. If it shows below 12.5V for a battery on the shelf you don't buy that battery.

/per

[Astroblagger]

will try charge it longer, my maplin 12v 17A/h battery instructions say to charge it for 24 hours, surely a 2-3 hour charge wont fully charge my 50A/h battery? 

[michael.h.f.wilkinson]

In the case of AGM batteries, a full discharge might be tolerated, but cycling a battery deeply (50% discharge or more) seriously reduces its lifespan. Another point is storage: I used to store my battery in an (almost) unheated garage, which keeps the scope's OTA close to outside temperature, which is great. It is not great for the battery. One died on me, and I have recently replaced it. I now store it inside, and frequently trickle charge it.

[Davey-T]

If you haul it down to a friendly local garage they'll have a  high discharge tester that will give an idea if it's holding a full charge.

Dave

[michael.h.f.wilkinson]

If you haul it down to a friendly local garage they'll have a  high discharge tester that will give an idea if it's holding a full charge.

Dave

I am not sure if all batteries are equally suitable for a high-discharge test. Check beforehand.

[Velvet]

leisure batteries will tolerate a higher discharge than car batteries, but on the converse they should be regularly charged.  Mine is on charge most of the time i am not using it.  the intelligent charger  charges

and discharges the battery to keep it in good condition.  if the battery is 2 years old and not been charged very regularly if highly discharged it may be beyond recovery

velvet

[lensman57]

Hello iv got a 50A/hour leisure battery, im just wandering if totally draining it and recharging it will be ok, reason being iv had power issues to my camera even when my charger says its fully charged,

Also how long do you think is normal for charging it after use my charger says its fully charged after 2-3 hours after iv used it for 5-6 hours after an imaging session. Just seems very quick to me?

You can discharge a leisure battery rated as deep cycle to about 50% and no more, it will need a full charge afterwards. Never discharge a conventional or Gel battery fully, you may never be able to charge it again.

A.G

[perfrej]

Charge times... A lead-acid battery (liquid or gel) will absorb 25 per cent of its rating at most. For a 50Ah battery, that means that no matter how much current you make available to the battery, it will suck in 13A and no more. Assuming perfect harmony, at least 4 hours. AGM batteries can suck in about 50 per cent of the rating, so given available power, half the time.

/per

[jetstream]

Deep cycle batteries are a must if not maintaining a constant charge and even then too "deep" a drain is not good.We use them on boats here but they only live for 2-3 years.They are not cheap either,some use a "smart" charger with success.

[opticalpath]

In the case of AGM batteries, a full discharge might be tolerated, but cycling a battery deeply (50% discharge or more) seriously reduces its lifespan. Another point is storage: I used to store my battery in an (almost) unheated garage, which keeps the scope's OTA close to outside temperature, which is great. It is not great for the battery. One died on me, and I have recently replaced it. I now store it inside, and frequently trickle charge it.

Absolutely agree.  Gel batteries used in standby applications, where they are kept in a constant 100% charged state (and rarely if ever are called upon to supply power!), can last many years.  But even deep-cycle batteries with thicker plates to withstand deeper discharge will have a short life if regularly discharged to less than 50%.  For longer life, go for a larger capacity battery that never needs so much taken out of it. 

Adrian

[michael.h.f.wilkinson]

Absolutely agree.  Gel batteries used in standby applications, where they are kept in a constant 100% charged state (and rarely if ever are called upon to supply power!), can last many years.  But even deep-cycle batteries with thicker plates to withstand deeper discharge will have a short life if regularly discharged to less than 50%.  For longer life, go for a larger capacity battery that never needs so much taken out of it. 

Adrian

I think this effect accounts for the bad rep of the 17Ah and even worse 7Ah power tanks. People claim the batteries are poor quality because they do not last long. They then point out (rightly) that a 50Ah or bigger leisure battery will last much longer. Where they are wrong is that this has little to do with the quality of the battery, but everything with the depth of cycling. If you use the same kit, drawing just 2 A from the battery for a long session, you cycle a 17Ah pack more than 50% easily. The same load draws perhaps 15% of your bigger battery. The difference in the number of cycles between a 15% cycle and 50-60% cycle is huge. Nothing to do with quality, everything with capacity.

[lensman57]

were designed to power the

I think this effect accounts for the bad rep of the 17Ah and even worse 7Ah power tanks. People claim the batteries are poor quality because they do not last long. They then point out (rightly) that a 50Ah or bigger leisure battery will last much longer. Where they are wrong is that this has little to do with the quality of the battery, but everything with the depth of cycling. If you use the same kit, drawing just 2 A from the battery for a long session, you cycle a 17Ah pack more than 50% easily. The same load draws perhaps 15% of your bigger battery. The difference in the number of cycles between a 15% cycle and 50-60% cycle is huge. Nothing to do with quality, everything with capacity.

Having looked at the design and the provided outlets of these power tanks ( I have the 7 Ah model that now refuses to be fully charged up, only a year old ) I am sure that these were designed to power a small GoTo mount, EQ5 PRO or HEQ5 Pro for short observing sessions perhaps up to an hour, they could probably just cope with a anti dew strip getting into the act half way through observing. I now doubt very much if these were ever intended for a long session of imaging - observing with multiple instruments attached. I only do short imaging sessions, up to 3 hours or so including the alignment routines and even the 17 Ah unit would probably only last about a couple of hours if the CCD, Dew stips and the Mount were Attached. Perhaps it would have been  more " Honest " and helpful to the enduser if these Power Tanks were rated and advertised at their 50% capacity ( the real practical capacity )  rather than Max current draw  that would render the battery dead.  I have now ordered the 22 Ah Tracer Lithium iron unit from FLO in preference to an AGM powered leisure unit mainly due to the lack of weight and size. I have damged muscles that support my back and there is no way that I could haul a 30 Kg battery in and out of the garage to the garden, perhaps for younger and fitter people with a permanent set up a 110 Ah AGM would be a much better choice, that would be the roughly the same price as the little Tracer that will  power the CCD and the Mount for up to 5 hours  for me.

Regards,

A.G

[michael.h.f.wilkinson]

Having looked at the design and the provided outlets of these power tanks ( I have the 7 Ah model that now refuses to be fully charged up, only a year old ) I am sure that these were designed to power a small GoTo mount, EQ5 PRO or HEQ5 Pro for short observing sessions perhaps up to an hour, they could probably just cope with a anti dew strip getting into the act half way through observing. I now doubt very much if these were ever intended for a long session of imaging - observing with multiple instruments attached. I only do short imaging sessions, up to 3 hours or so including the alignment routines and even the 17 Ah unit would probably only last about a couple of hours if the CCD, Dew stips and the Mount were Attached. Perhaps it would have been more " Honest " and helpful to the enduser if these Power Tanks were rated and advertised at their 50% capacity ( the real practical capacity ) rather than Max current draw that would render the battery dead. I have now ordered the 22 Ah Tracer Lithium iron unit from FLO in preference to an AGM powered leisure unit mainly due to the lack of weight and size. I have damged muscles that support my back and there is no way that I could haul a 30 Kg battery in and out of the garage to the garden, perhaps for younger and fitter people with a permanent set up a 110 Ah AGM would be a much better choice, that would be the roughly the same price as the little Tracer that will power the CCD and the Mount for up to 5 hours for me.

Regards,

A.G

Totally agree. My revamped (now 22Ah) pack is fine to drive the RA motor for hours on end, and a dew strip on a controller (but only on very humid nights), but no more. Imaging will require a bigger battery

[Astroblagger]

I charged the battery most of the day, when checking the voltage across it only 12v, so I think it's definitely goosed. Will go for an 88a/h battery, as it will never be discharged too much.