The Maplin Jump Start with 17Ah SLA

The Maplin Jump Start with 17Ah SLA which my wife bought me for Christmas (hints required - like price goes back up to £45 from £20 on the 24th) went back to the shop today. I wanted it for the cheap battery to provide power to an inverter running the boiler and central heating pump in the event of mains failure. It ran for precisely 10 minutes. No problem I'll just charge the battery. Nope, the 12v 500mA wart produced an unhealthy 3v (off load) and the charging LED remained black. So used the nice Lidl charger (Tronic T4X) which finished charging in 1.5 hours (now it charges at a max of 3.6A so that would be only about 5Ah into the "17Ah" battery). Anyway a simple car bulb load test showed 6A could be supplied for a full 15 minutes before the voltage dropped to below 10v (so about 1.5Ah). One final test using a power supply with voltage and current monitoring and charging to 14.8v produced similar results. Looking at some Chinese spec sheets a typical 17Ah battery (at the 20 hour rate) should supply 10 amps for an hour so this specimen was well duff. The shop said they sold 300 before Christmas and this was only the second returned (for a refund - stock was zero and would have to be ordered from head office).

Geo

Reply to
Geo
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I've bought a couple of these from CPC, some years apart. Mine has done excellent service, but that crappy wall wart charger is best disposed of and a proper SLA charger used. I ran my heating for an hour, but I've never run it flat, so I don't know what the real capacity is -- I've no reason to think it's any less than the 17Ahr advertised. A friend bought one at the same time and accidentally left it charging on that wall wart for days, which completely wrote off the battery. It's just an unregulated power supply which limits current with its internal resistance.

The second one was bought as a present for my brother. Due to it have being dropped and smashed to pieces, I got to see the innards, before returning it for a replacement. The battery was a respectable make (can't recall which), but the quality of some of the other components was much reduced over the one I bought earlier, such as the compressor hose and tyre valve adaptor, which didn't fit well on the tyre valves, and probably won't manage more than about 10 attachments to a tyre valve before breaking.

Reply to
Andrew Gabriel

Geo laid this down on his screen :

I bought one from a car boot sale three or four years ago and it is still going strong. It has a built in charge control - a relay makes as the charger is plugged in, LED comes on and it drops out at 14.4v exactly. I have it plugged in to a four way 13amp strip, which itself is fed from a cheap time clock set to power up once per day for one hour. The four way has several similar chargers plugged in and it keeps drill batteries etc. topped up, ready to use.

The only time I needed it to start my 3L car up, it just didn't have anywhere near the capacity to do it - but the amp/hours do seem close to its rating.

Reply to
Harry Bloomfield

I was given a Ring one a few years ago, it still seems good. It seems to have its own charge limiter as it has a led indicator that changes to green when charged (it also has 3 leds on the side to indicate satte of charge.

I use it to power a small laptop blower for a cookstove , so it sees a lot of use apart from bicycle tyres.

AJH

Reply to
andrew

I bought one from Halfords but it cost me £59 in November. The one day I wanted to start the car with it and it turned over once. It was flat! There is no way on earth this device can start a car. I got a refund immediately when I offered to demonstrate it fully charged to Halfords. They said, "we know, we've had most of them back". Even one of the shopping channels lied about starting a car with one. I phoned and asked them to show me it starting a car in the demo, so they left the original car battery hooked up!

Reply to
Frank

Mine bought from Lidl some years ago for 20 quid - when the identical item cost 45 at Halfords - does switch off after charging by the LED indicator. And is a constant voltage charger - correct for SLAs. I tried to start a neighbour's 3 litre car with it the other day and it wouldn't even turn over so I'd guess the battery is knackered - although the compressor still works fine. It certainly doesn't owe me anything.

Reply to
Dave Plowman (News)

Mine has started several cars - but not with totally flat batteries.

Reply to
Dave Plowman (News)

Mixed experiences then - I had a quick look inside before it went back. The battery was certainly marked 17Ah although I can't recall the manufacturer. The "charging" PCB contained just a largish size low value resistor, a series diode and a resistor for the LED. Oh - and the cheap (moving-iron?) voltmeter was undamped and jammed at the endstop when pressing the button to read when in the fully charged zone.

I am now looking at the price of maintenance-free car batteries instead. My pump and boiler take about .37 Amp at 240V so will need at least 7A+ to run the inverter.

Reply to
Geo

I was given one of these a few years ago as a Christmas present, the tire compressor gives up at around 84PSI (good enough for tires I know but I wanted it for toy aeroplane retracts) the lamp and the votmeter died within weeks, the battery would not turn over the 1.6l petrol engine in my car (even with the original battery in parallel) and then it s.o.'d its m.c. recently at around 3 years old despite being charged every couple of months.

The only thing I bothered to save out of it was the jump-leads, these have a connector that will take an M5 screw so I could use the 44Ah SLA I use to charge model planes at the field if I ever need to jump start the car again.

At =A320 they don't cost much more than just the jump leads but the quality of the rest of it is utter crap in my experience.

David

Reply to
mangled_us

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