Leisure battery charger?

[Demonperformer]

Do the people who currently use leisure batteries think that http://www.maplin.co.uk/solar-powered-12v-1.5w-battery-trickle-charger-98358 would be suitable for keeping one charged up ready for those (all too infrequent) clear nights?

It does have couple of bigger brothers, http://www.maplin.co.uk/solar-powered-12v-2.4w-battery-trickle-charger-223251 & http://www.maplin.co.uk/solar-powered-12v-4.8w-battery-charger-115194 but they are considerably more expensive.

If I go down the leisure battery route, I would like to get it topped up by solar rather than mains if possible.  Maybe I would be able to use a dual system - mains when it drops below a certain level and then back to solar?

All thoughts appreciated.

Thanks.

[Charic]

Demonperformer..........Hi I purchased one last Friday and testing since Saturday, its charging  a 12v battery  @ 12.25 volts now reading 12.29, so not massive, but then its not designed to be massive, just a trickle. and for under a tenner, who cares! This one will be attached to a deep cell battery powering an electric fence, through the Winter Months, as last year during the cold, we needed to re-charge the battery weekly?? This newer battery has lasted nearly 4 Weeks in-situ already and still over 12. volts, so the Solar panel will help a little, if at all! One thing to note, Sunny skies are better, but it does charge when overcast.

[Demonperformer]

Thanks for the response.

I tend to agree with your comment "for under a tenner, who cares".  So I think I will make a trip down to the local Maplins when I get the chance (preferably before they sell out!).

It is just a little ironic that during the winter months, when nights are longer and dew is heavier and so the drain on the battery will be higher, the days are shorter and cloudier and so charging will be less efficient.

Just another one of those things that make the life of the stargazer "fun".

[Bizibilder]

For a leisure battery you really require a charger/conditioner like these: http://www.tayna.co.uk/Leisure-Battery-Chargers-S923-1.html   They will keep your leisure battery in good condition for years.  Expensive? yes but worth it when you look at what you pay for the battery in the first place.  My own 85Ah battery is still as good as new after nearly four years using one of these.  I don't use it much these days so it goes on the charger for a couple of days a month just to keep it going.

[Demonperformer]

Thanks for the response.

The battery I was looking at was 125Ah for £89 (with 4 year warranty), but this would require the bigger charger at £5 more than the battery itself!

Maybe time for a rethink ....

[StuW]

I've seen good reviews of these, plus it float charges so you can leave it on all the time.
http://www.amazon.co.uk/Ring-Automotive-RSC508-Smart-Charger/dp/B00499DTW4

[jonathan]

I have one of these which is the bigger brother of the one StuW mentioned.  I haven't really done enough charges or had my leisure battery for long enough to give much feedback on it, but it has managed to recondition one of my cheap Maplins 5-in-1 batteries to the point where I think it's as good as it's ever going to be.  Put it this way - I trust this more than I trust a typical car battery charger (one with wood-effect sides and an analogue ammeter, you know the kind), although in reality they probably do just the same routine when it comes to normal charging.

The thing about those trickle solar chargers is they are not designed to fill a heavily drained battery, they are meant for applications where there is a small discharge over a long period, such as a caravan battery that is sitting idle; if you calculate their typical output vs the amount of charge you are likely to need after one night's viewing, it might take several days of sunshine to charge it up to full capacity, and I don't know if the charging rate will be that good for the battery as traditional chargers usually tail off the amps as the battery charges up, do those solar chargers have that function?

Also, solar chargers only work with good batteries, they will stand no chance with a weak or failing battery whereas a smart charger might be able to recondition it at least partially.

If I was going to go solar, it would be a huge panel or two mounted in the garden, no messing around with little Maplins jobbies.  I'm sure the local busy bodies would complain that we didn't have planning permission for it though!  There is basically no chance of mounting panels on our roof, not even on the out-buildings.

Besides all of that, 125mAh?  That will be a BIG battery, I think you could probably get away with half that, unless you are planning a week-long trip away from any power source.  Kinda wish I'd bought a smaller one, it's just another heavy item I'd rather not have to lug in and out of the house (even though I have it in a wheeled tool box, it takes up a lot of space and the wheels make a lot of noise late at night).

Another thing to know about leisure batteries is that they usually require good ventilation during charging (I'm sure the retailer should tell you this) as they can produce a flammable gas, mine came with a little tube attachment for venting to outside, so long as you don't charge them in a confined space such as a sealed box (which would become a potential gas bomb) it's fine.

[Demonperformer]

Thanks for the replies, lots to think about.

Maybe it would help if I go back to my thinking about the battery itself.

My starting point was this website, which was recommended to me: http://www.alpha-batteries.co.uk/leisure-batteries/?ab_voltage=20&price=-100 and the battery I mentioned above is the 125AH Xplorer Deep Cycle Leisure Battery (4th one down on the first page).

Key points for me were:
(1) Capacity - I have seen posts on SGL saying you should go for 100Ah+. As I understand this, it is not only a case of using it all, but as the charge in a battery starts to go down, it starts to be unreliable when asked to deliver a heavy load (the example I was given was a discharged car battery may power the lights, wipers and fan, but can totally fail to deliver when asked to turn the starter motor) therefore go for a wide margin over what you think you will use in a session.
(2) Warranty - A battery that has a 4-year warranty should be better than a battery with a 3-year warranty (if a battery is going to fail after 3.5 years, they aren't going to stick a 4-year warranty on it and have the replacement costs, and if the 3-year warranty batteries were as good, they would put a 4-year warranty on them as well rather than making people think they were no good).
(3) Dual layout - not totally sure this is important - depends how I finally end up connecting everything to it - but it gives me choice. So for the same price I would go for dual layout (with choice) rather than single layout (no choice).

The other two batteries here that meet these three criteria are: 105 AH Lucas Deep Cycle Leisure Battery and 113 AH Lucas Deep Cycle Leisure Battery, which at £95 for either, they are both lower capacity/higher price.

The only way to go cheaper is to go for single layout (standard round) and a shorter warranty (3 years). I could now get 100Ah for £70 (£20 saving) or 110Ah for £75 (£15 saving). Ignoring the layout, I am still only getting 75% warranty for 77% price (with only 80% capacity) or 83% price (with 88% capacity).

Based on the above, I concluded that the 125AH was the best value for money.  Unless I am missing something.

Having checked, most of the smaller capacity batteries have shorter warranties (2/3 years) which makes me a little 'twitchy'. There is the 88Ah Xplorer Deep Cycle Leisure Battery with 88Ah (70% capacity) for £70 (77% price) which I guess is close to similar value. It is significantly shorter (length) and a little less high, similar width. Weight not quoted. Of course, if I go for a smaller capacity, I will be using a greater proportion of that capacity in any one session, which would make the use of one of these solar-chargers less effective and so a greater reliance on mains power.

Really, I am trying to think of ways I can reduce the 'running costs' in terms of mains power in the long run, with energy prices going the way they are. I was also wondering about some sort of 'switcher circuit' that would use the solar charger to keep it at full capacity while it is not being used, but would pull in mains power if the power was below a certain level.

So many things to consider.

[reader34]

Thanks for the replies, lots to think about.

Maybe it would help if I go back to my thinking about the battery itself.

My starting point was this website, which was recommended to me: http://www.alpha-batteries.co.uk/leisure-batteries/?ab_voltage=20&price=-100 and the battery I mentioned above is the 125AH Xplorer Deep Cycle Leisure Battery (4th one down on the first page).

Key points for me were:

(1) Capacity - I have seen posts on SGL saying you should go for 100Ah+. As I understand this, it is not only a case of using it all, but as the charge in a battery starts to go down, it starts to be unreliable when asked to deliver a heavy load (the example I was given was a discharged car battery may power the lights, wipers and fan, but can totally fail to deliver when asked to turn the starter motor) therefore go for a wide margin over what you think you will use in a session.

(2) Warranty - A battery that has a 4-year warranty should be better than a battery with a 3-year warranty (if a battery is going to fail after 3.5 years, they aren't going to stick a 4-year warranty on it and have the replacement costs, and if the 3-year warranty batteries were as good, they would put a 4-year warranty on them as well rather than making people think they were no good).

(3) Dual layout - not totally sure this is important - depends how I finally end up connecting everything to it - but it gives me choice. So for the same price I would go for dual layout (with choice) rather than single layout (no choice).

The other two batteries here that meet these three criteria are: 105 AH Lucas Deep Cycle Leisure Battery and 113 AH Lucas Deep Cycle Leisure Battery, which at £95 for either, they are both lower capacity/higher price.

The only way to go cheaper is to go for single layout (standard round) and a shorter warranty (3 years). I could now get 100Ah for £70 (£20 saving) or 110Ah for £75 (£15 saving). Ignoring the layout, I am still only getting 75% warranty for 77% price (with only 80% capacity) or 83% price (with 88% capacity).

Based on the above, I concluded that the 125AH was the best value for money.  Unless I am missing something.

Having checked, most of the smaller capacity batteries have shorter warranties (2/3 years) which makes me a little 'twitchy'. There is the 88Ah Xplorer Deep Cycle Leisure Battery with 88Ah (70% capacity) for £70 (77% price) which I guess is close to similar value. It is significantly shorter (length) and a little less high, similar width. Weight not quoted. Of course, if I go for a smaller capacity, I will be using a greater proportion of that capacity in any one session, which would make the use of one of these solar-chargers less effective and so a greater reliance on mains power.

Really, I am trying to think of ways I can reduce the 'running costs' in terms of mains power in the long run, with energy prices going the way they are. I was also wondering about some sort of 'switcher circuit' that would use the solar charger to keep it at full capacity while it is not being used, but would pull in mains power if the power was below a certain level.

So many things to consider.

Hey White Dwarf. 

Have you made a decision on your battery? I'm interested to know!

Reader.

[Demonperformer]

I haven't gone with a battery at the moment - thinking maybe the money would be better spent in putting in an external mains supply.

All my astro is done in the garden, so mobile power source not essential, and if I am going to have to keep the battery charged from the mains anyway, it is going to cost me more to run the battery (you can never get out as much as you put in).  Two months without any work has meant I have had to pull my belt in a little, so nothing actually done with this so far - still running an extension lead out of the back door, but that doesn't do anything for the temperature inside the house on these cold nights!

[lardy]

If all your Astro is done from your garden why such a large capacity battery?  If its just the mount & dew bands you could reduce the size of battery and save money … The CTEK charger/conditioner is an excellent bit of kit and IMO worth the outlay, it'll keep the battery charged and conditioned and cost pennies to use. Going down the solar charge route is adding complication and cost.

240 volts + moisture/dew or 12 volts + moisture/dew …. I know which one I prefer to use :-)

[LDUNN1]

I am not sure you are comparing apples with apples there.

That 125Ah battery that you link to (the 4h one down on the first page) is rated as 125Ah @100hr - the more standard measurement is @20hr (aka C20), & according to the specs, that 125Ah battery drops to 105Ah @20hr. That might still be okay for you, but I just wanted to point out the potential difference when comparing these batteries.

For info, I use a high quality 85Ah (c20) AGM battery & that gets me through the night (dusk till dawn) running an AP900 mount, two dew straps, CCD, electronic focuser, electronic camera rotator & my netbook once its onboard battery starts to become depleated.

 

The other thing you should consider if you have a mobile setup (& if you don't why do you want a battery?!) is the weight of the battery. I had intended to get the higher capacity version of my battery, but having lifted both in the shop, I decided to go with the 'lighter' lower capacity battery which was 25kg - I noticed the extra 5kg to the higher capacity battery.

Also remember that the larger capacity battery you have, the longer it will take to recharge with a given charger. For example, if I run all night on my battery it will be depleated, & I might put it back on charge at 6am, I might take it off charge at 4pm ready to go out the following night - that is 10hrs recharge time, so the recharge rate of your charger becomes critical. Mine (a CTEK MX5 which I would recommend) has a max charge of 5A/hr so I am not going to be able to put a full charge back in during the short winters day. The CTEK MX5 at 5A/Hr is a relatively high charge rate, so don't skimp on the charger, you could easily end up with one down at 2 or 3A/hr & then you would be waiting several days to recharge fully following a session.


If I were to do it all again, I think I would seriously look at the Tracer Lithium Ion batteries, despite the cost.


 

[jonathan]

You're currently using a 240v - 12v transformer which will 'lose' some power in the conversion too, depending on the quality of your step-down circuit.  While I don't doubt that using a battery will 'lose' more of that power, not least because the battery will drain over time if not used (the higher the quality, the less this should be a factor), I think the difference may not be a much as you think.  Perhaps the only way to tell is to use a power meter plug and test to see what you're actually paying per hour to run the scope off mains or battery.

My battery charger (the Ring one) goes up to 6A charging rate, but I only ever use it on the 2A rate.  It takes several hours to charge the battery (typically used for about two hours running NEQ6 and three dew heater tapes) but while I don't need to use the higher rate I won't.  The charger automatically reduces the rate as the battery fills up.

[Epicyclus Dave]

Hello , i use one of these smart chargers for my 90Ah AGM battery , http://www.ringautomotive.co.uk/uk/products/Cars/Battery+Care/SmartCharge-plus-/RSC512

I re-charge after a night out at a remote site with the scope and once a month if hampered by clouds

My current draw for my set up is (neq6 / laptop / dew heaters) about 4 Amps on the battery and it easily does an 11 hour constant run before reaching 50% discharge level.

Dave.

[fondofchips]

Trickle chargers are commonly used on motorcycles to keep batteries charged so the security alarms don't go off due to low battery voltage.

You may find they are cheaper than the ones generally found for other applications.

[Demonperformer]

(& if you don't why do you want a battery?!)

Well I need to organise some means of powering the setup without heating the garden (by having to keep the back door open with a power lead running out through it.  That means either installing an external power socket or using a battery of some sort.

[jonathan]

Well I need to organise some means of powering the setup without heating the garden (by having to keep the back door open with a power lead running out through it.  That means either installing an external power socket or using a battery of some sort.

I've got the answer - a polytunnel.  Extend it from your back door to your observing site and install a pair of gloves in the end so that you can operate the telescope mount, and have a small opening to look into the eyepiece.  Minimal heat loss!

[LDUNN1]

.......I have dropped in a small diameter (60mm?) drain pipe just under the surface & at the back of my wife's flower bed - for me this runs from the back door to my observing site when I observe from the garden. I plan to run an outdoor armoured mains cable & a cat5 cable down the pipe at some point & drill a hole through the wall into the house to pass the pipe & cables through. This will save time & effort running cables up & down the garden at the start & end of each session & means I can keep the back door closed! The pipe work was not expensive & being black & mostly buried just under the surface doesn't look 'bad' during daylight hours. 

[Captain Tweaky]

I've stumbled across this interesting and varied discussion   and thought I should just add my 2-haporth.

You would be hugely amused to know that if you install an outdoor mains socket you are obliged to inform your 'Local Building Regulations Control Department'. If the socket is not already certified by a competent electrician you must ask someone from this worthy department to come and assess and certify the installation at your expense!!     

Otherwise I should also highly recommend the CTEK MXS 5.0T Battery Charger as I use one for my golf trolley gel battery, another 17ah gel battery and a 75ah leisure battery - it is very good.

Yours aye - Cap'n

[Demonperformer]

Interesting to know.  Although a little academic in my case.  If I go for an external power supply, I'm going to have to get someone competent to fit it anyway.

BR_PDF_AD_P_2013.pdf

[Demonperformer]

That 125Ah battery that you link to (the 4h one down on the first page) is rated as 125Ah @100hr - the more standard measurement is @20hr (aka C20), & according to the specs, that 125Ah battery drops to 105Ah @20hr. That might still be okay for you, but I just wanted to point out the potential difference when comparing these batteries.

IGNORANCE ALERT!! (mine, not yours )

I have no idea of the implications of the @xxhr.

My initial thoughts on reading "125Ah battery drops to 105Ah @ 20hr" is that I would still have 105 left after using 20 of the 125 that I started with, which is more or less what I would have expected.  But that does not seem to gel with the comment that it is "125Ah@100hr" (which by the same logic would suggest means I still have 125 hours left after using 100, and even I know that cannot be right!)

Could you provide a little more explanation?

Thanks.

[Demonperformer]

You're currently using a 240v - 12v transformer which will 'lose' some power in the conversion too, depending on the quality of your step-down circuit.  While I don't doubt that using a battery will 'lose' more of that power, not least because the battery will drain over time if not used (the higher the quality, the less this should be a factor), I think the difference may not be a much as you think.  Perhaps the only way to tell is to use a power meter plug and test to see what you're actually paying per hour to run the scope off mains or battery.

I had not considered the transformer-loss part of the equation.

As you suggest, maybe the best thing to do is to get something like http://www.amazon.co.uk/Energenie-ENER007-Power-Meter/dp/B003ELLGDC/ref=pd_sim_diy_18 and find out exactly how much my setup is costing to run in practice.  Then I would have some genuine figures to work with rather than just fuzzy assumptions.

Thanks.