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Maplins Battery Project

jonathan

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jonathan

jonathan

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OK, after seemingly losing my Maplins 17Ah battery due to my own negligence (not recharging at every opportunity, which seems to be a requirement for lead-acid) I decided to do something about it.

Thanks to some great info provided by other members in a previous thread regarding the blinking light on an NEQ6 (I'm 95% certain now that it is the battery that has died in my case, not some problem with the mount) I have sourced a gel battery which should be a massive improvement over the bog-standard lead-acid one that came in the Maplins power tank (and probably in all those other power tanks too).

Here is my Maplins power tank with the cover open:

maplins_battery1.jpg?t=1318076113

In there is the 12v 17Ah battery, looks like a very cheaply made one from China, in the other half is the compressor (great bit of kit for astronomy! Use it to inflate that Radio 2 inflatable chair?), then there's the wiring and bit of electronics that does the two USB ports and LED torch (eight super-bright white LEDs, must be 1.5v each as the supply comes directly from the battery). All told, it's quite a tidy unit, no complaints about the quality of workmanship. The case is rugged enough for my purposes and comes with a big handle which I like.

I have sourced a 12v 17Ah Gel battery with almost identical dimensions, there is just one or two mm in it so it should fit - Haze HzY-EV12-18 Gel Mobility Batteries 12v 17ah.

A suitable charger should keep it right, I'm looking at this - Numax 120400 Single Battery Charger Chargers 12v 4ah. I would just connect up the clips to the jump leads on the Maplins power tank for charging, as they connect directly to the battery.

The place I found online that keeps cropping up in searches is Steve's Batteries, looks to be a mail-order place near Preston judging by the postcode. Anybody had any dealings with them?

These are the parts from their website:

Haze HzY-EV12-18 Gel Mobility Batteries 12v 17ah

Numax 120400 Single Battery Charger Chargers 12v 4ah

Comments and thoughts appreciated!

PS.. Presumably the same or similar battery and charger could be fitted to the Skywatcher / Celestron power tanks.

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Bizibilder

Bizibilder

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Looks to be OK - I would make one suggestion, why not go for something like the 75Ah Leisure battery (same website). A little more expensive but it will run all your kit for hours even if you add things like dew heaters/laptop/cameras etc. You may not have these at the moment but you may want to future proof yourself. These batteries and chargers are not cheap!

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jonathan

jonathan

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Looks to be OK - I would make one suggestion, why not go for something like the 75Ah Leisure battery (same website). A little more expensive but it will run all your kit for hours even if you add things like dew heaters/laptop/cameras etc. You may not have these at the moment but you may want to future proof yourself. These batteries and chargers are not cheap!

The Leisure battery range is Lead-acid, I am looking at Gel batteries which will not have the same charge / discharge characteristics (e.g. flaws) as my current battery. The 75Ah Gel battery costs £110, quite a step up from the 17Ah at £40 as well as being very large and heavy (definitely would need a big case, no chance it would fit in the Maplins power tank, and would do my back no good!)

If my mount plus 2x dew heater tapes draw 2A then I will be happy to get two night's viewing out of a 17Ah battery between charges, I should get the full 17Ah from it too without causing any damage because of a full discharge, being Gel instead of Lead-acid.

There is a 245Ah Gel battery which costs a cool £343, looks like an ammo crate and probably weighs as much. I think I would mount this on some form of skate board and just kick it around rather than try to lift it!

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jonathan

jonathan

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cant believe they are only 17ah.

That's the same Ah as the larger Skywatcher power tank, and from what I read you will only get half of that before you ruin the battery as Lead-acid is not good for deep cycles.

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  • 4 weeks later...
perfrej

perfrej

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Folks,

Gel lead/acid batteries are also severly damaged by discharge below 10.5 V but will recover slightly better than liquid lead/acid. The only lead/acid technology that has a good recovery from discharge is AGM (Advanced Glass Mat). About 50-100% more expensive than normal liquid lead/acid but well worth the extra dough.

The thread mentioned above is a good thread with lots of information.

So, bottom line:

Liquid L/A: no recovery, first shot below 10.5 causes damage

Gel L/A: better recovery, but damage still done, albeit not as bad

AGM L/A: may well recover from 0V discharge level!

In fact, on a side note, I have seen a manufacturer spec for retailers regarding AGMs that stated that battery should not be shotrcircuited on the shelf for more than 90 days! I have dual AGMs factory installed in my VW and they are just totally fantastic. Also, the boat has a pair of 90AH AGMs - perfect for the fridge!

All the best from a cloudy Stockholm

Per

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malc-c

malc-c

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I purchased a second hand Maplin power tank with a 17 a/h battery in it. Charged it up for two days with the supplied 500mA psu/charger, worked fine, but then a week or so later went to use it and it bombed out (DEC motor buzzing which is the normal sign of low voltage) - pressed the test button and hi hardly kicked above the min setting. Could it be that the battery has been damaged and now won't hold a charge ?

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BAZ Senior

BAZ Senior

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It sounds like it, the supplied chargers only trickle charge them and can take ages to charge up after use. If it hasn't been charged regularly by the previous owner it may be too flat to bring back.

Try connecting it to a car battery charger which will put in a bigger load, but keep an eye on it. Charge these at least once a month to keep them happy.

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Chris Rowland

Chris Rowland

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It's not a good idea to use a car battery charger with a sealed lead acid battery because the charging voltage and current is too high. When a car battery is fully charged it electrolyses the water in the battery, this bubbles off as hydrogen and oxygen. In a SLA the gasses vent but can't be replaced.

The charger should end up at about 13.8V and delivering only a few mA.

You will be better off with a charger designed for the sealed batteries.

Chris

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davebodger

davebodger

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As far as I know Gel cells come in different versions - some are suitable for deep discharge but some aren't. Best policy with lead-acid batteries is don't discharge below 50% unless you are very sure your battery is DD capable.

I just got one of these Maplins 5-in-1 jumpstarter units as jonathan pictures above, as they are on special offer (£10 off) but the box said "now contains spiral-wound battery for improved performance" so being inquisative I took it apart and found the new battery is only 9AH. It's a bit lighter than the 17AH battery and may well be enough for me so I'm not complaining. I took off the cover from the LED light and used it as a template to cut a piece of red filter gel. Stuffed it in the hole and screwed the cover back on - instant red light conversion. :-)

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