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Forum Index : Electronics : Gen starter batt SLA problems

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domwild
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Joined: 16/12/2005
Location: Australia
Posts: 873
Posted: 12:51pm 04 Dec 2013
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Hi,

909 inverter gen 3300W with small 12V 4.5Ah SLA for starting. The manual warns you about trying to start the gen after purchase as the batt is most likely flat from storage. But I have now been running the gen for two hours and the starting relay is still rattling only.

909 is suggesting charging the batt, which is what I did with a 2.5Amp motor cycle batt charger. The voltage rises to 15.4V during charging, which I stopped as I do not like anything above 14.7 but I may be mistaken. After a very brief charging I read the at-rest voltage and it was 11.8V.

Not that I do mind hand-starting this gen but it might just be a good idea to get a new battery if this forum is suggesting this batt is stuffed and 909 comes to the party.

Help!
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill
 
Downwind

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Joined: 09/09/2009
Location: Australia
Posts: 2333
Posted: 01:20pm 04 Dec 2013
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For a 12v SLA battery the float charge is 13.8v and the bulk charge should not exceed 14.2v.

SLA batteries stuff up quickly if stored and not kept topped up regularly.
Sometimes it just works
 
domwild
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Joined: 16/12/2005
Location: Australia
Posts: 873
Posted: 12:18am 05 Dec 2013
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Thanks Downwind. This was a demo model and probably had been hanging around the store for too long.
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill
 
domwild
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Joined: 16/12/2005
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Posts: 873
Posted: 09:20pm 22 Dec 2013
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909 promised to send me a new SLA and I am praying for it. But for that price I do not mind hand starting it.
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill
 
Downwind

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Posted: 11:47pm 22 Dec 2013
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Perhaps you might get a late Xmas present if you are lucky, if not remind 909 that you are waiting !!!

Pete.
Sometimes it just works
 
domwild
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Location: Australia
Posts: 873
Posted: 12:52pm 23 Dec 2013
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Are you hinting that a shop like Masters would have to open all the boxes of generators and regularly recharge the SLAs to keep them in good nick? This would be very hard to do.

Thanks for wishing me a Chrissi pressi!
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill
 
M Del
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Joined: 09/04/2012
Location: Australia
Posts: 155
Posted: 04:27pm 23 Dec 2013
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I do not think any store based battery retailer would have staff that would even know how to check the charge state of a battery let alone be allowed to waste time maintaining them.

I was looking for a couple of 12v 7ah SLABs for a project. I took my multimeter and could not find one over 11v (lots around 10-10.5). Most of the batteries were still in cardboard boxes and it took a bit of effort to get a staff member to allow me to open and test them.
The boxes were factory sealed and date stamped, some were 2 years old by the stamps.
Figured if a battery has sat flat for two years it might only be worth scrap value and not worth the effort.

The stores included both the big box chains, several electronic/electrical stores and a couple of large hardware retail outlets.

Finally drove a bit of distance to a battery world and got a couple from them.

Don't know if this is the same in all areas but that is the situation in my area.

Mark
 
Downwind

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Posted: 11:56pm 23 Dec 2013
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You are not the only one who takes a MM and tests the SLA batteries before buying them.

I agree most SLA batteries on shelf for sale are past their prime.

SLA batteries dont last long when left to sit around and not maintained, new or old, if it was myself i would much rather a FLA battery as backup start than a SLA, at least a FLA you can check and will handle a little worst treatment than a SLA.

A small 12v motorcycle FLA battery would be my choice.

Pete.
Sometimes it just works
 
domwild
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Posts: 873
Posted: 12:51pm 07 Jan 2014
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Thanks, Pete for the advice re SLAs as I also have a UPS which uses three SLAs as it is a 36V (!) UPS and I would have blundered into losing lots of mulla buying them without being armed with a volt meter. Slight problem in sticking with FLAs instead of SLAs is that the charging voltages are slightly different for both types. From memory the UPS does not charge high enough for a FLA.
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill
 
Downwind

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Posted: 08:23pm 07 Jan 2014
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One thing i have noticed with UPS and SLA batteries, is often the batteries are neatly packed inside the UPS housing, making it a tidy compact unit.

This has a effect that shortens the battery life, due to the constant heat of the UPS, it simply dries the SLA cells out.

What i have done is solder heavy cables to the terminals inside the ups and placed the SLA cells outside the UPS, in many cases it dont matter with the cells external as once the Ups is in place we never move them anyway.

This method greatly extends the battery life and allows for perodic checking of the cells with a meter.

Pete.
Sometimes it just works
 
domwild
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Location: Australia
Posts: 873
Posted: 01:25pm 08 Jan 2014
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Pete,

Thanks for that. You are correct, for this UPS there was a separate metal box for the batteries.

I am just wondering if it is worthwhile to go to the expense of buying three SLAs and hoping that our power failures in the bush are only 30 minutes long and that one can run the "essentials", like TV and light for the 30 minutes or so of the failure before I have to drag the generator out if the failure persists.

A UPS in offices is only running PCs until the disk contents are safely backed up. Am dreaming up a use for this UPS I received.
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill
 
M Del
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Joined: 09/04/2012
Location: Australia
Posts: 155
Posted: 06:02pm 08 Jan 2014
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Hi Domwild, what is the type and specs on the UPS you have.

There are many different ones out there and some of them are designed to operate for the time required to save and shut down computers and some are designed to run for hours.

If you have a short use UPS there has been some success installing small fans(12v or computer) in them to increase reliable running time. Heat is normally the killer for a short use unit as the electronics/inverter have been known to burn out if external batteries are fitted and the unit runs for extended time.

I have a small brick unit for my wife's computer (SLA currently dead) and have used larger ones in the bush to smooth out erratic gen set operation to enable computers to be safely operated(plus kettle, phone charger, toaster etc).

Mark

Mark
 
domwild
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Joined: 16/12/2005
Location: Australia
Posts: 873
Posted: 09:51pm 09 Jan 2014
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Mark,

The unit is a Select 2000, 1500W, four 240VAC sockets, takes 12.2A 240VAC as its input, made in GB. 36VDC SLAs. From memory there is a fan inside anyway.

Does that help? I have no idea what sort of SLAs or FLAs in Amphrs I should connect, do you?

What sort of a gen did you have, inverter or modified sine? My generator tells me I should use a surge thingy. Stuck there because there are too many types around and some only open on lightning surges I believe. Also not sure if my UPS generates a modified or pure sine but I guess they normally use them in offices and therefore they should be pure sine to drive PCs. Then there is the question if UPSs smooth out what you call " ... erratic gen set operation ..." and how would they do it?

I have a Sola power conditioner with a huge transformer and an even huger capacitor and wonder if I should use it.

So many questions, so little time!
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill
 
Downwind

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Joined: 09/09/2009
Location: Australia
Posts: 2333
Posted: 10:15pm 09 Jan 2014
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  Quote  Also not sure if my UPS generates a modified or pure sine but I guess they normally use them in offices and therefore they should be pure sine to drive PCs.


Modified sine would be my guess, as computers and equipment with switchmode power supplies dont care much if its pure sine or not.

Ups are normally not very efficent inverters, and likely waste as much power as they supply, all they are designed to do is keep stuff online long enough so you can save and back up your files, not for a emergency backup power supply.

Really if your generator is so erratic to cause problems then your are better off getting rid of it and replacing it.

If your generator can maintain a steady 3000 RPM then there should be no problem, as 3000 / 60 = 50Hz.

Often with old and worn generators the motor struggles to maintain constant revs and gives problems, worn carbies, worn goveners, old fuel, excess load, or light loads where the motor hunts in rpm are a few problems.

Pete.
Sometimes it just works
 
M Del
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Joined: 09/04/2012
Location: Australia
Posts: 155
Posted: 12:49am 10 Jan 2014
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Hi Domwild

We used two sizes of gen set, 2.5 kva which was modified sine wave and 16kva which I believe was pure sine wave.
We used a UPS because occasionally some twit would plug an urn into a cable of the 2.5 and the resulting chaos killed a couple of battery chargers (AA & D cell) and lap top charges. Not an issue when we had the 16 up and running.
Also had the problem of clowns not turning the power off when restarting after running out of fuel which killed some of the control boards on the 2.5 gensets.

The UPS unit we used had 4 yellow top optimas connected to power it. It was not small or light weight.




Mark
 
domwild
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Joined: 16/12/2005
Location: Australia
Posts: 873
Posted: 08:59pm 10 Jan 2014
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Thanks for answers. The inverter runs OK during testing in the bush. It does not seem to have fixed RPMs, have noticed that in "Economy Mode" the RPMs are lower and in that mode the fridge causes an overload condition with the warning light "Overload" going on. Switching the inverter into "Normal Mode", the RPMs increase and it starts the fridge.
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill
 
M Del
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Joined: 09/04/2012
Location: Australia
Posts: 155
Posted: 09:29pm 10 Jan 2014
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From that I would say your generator/inverter when running on economy is not running fast enough to maintain proper voltage and Hz when a larger load kicks in. Economy mode is probably designed to power lights and other low power items not critical of Hz freqs.

We had some 5kva generators that ran slightly slow (governors gummed up from lack of servicing) that could have the governor overridden up to a point.
Hz of 48 could be reset by spring and lever manipulation to achieve 50Hz.
However Hz would then rise too high when the load and speed increased and that bought on a different set of problems.

Mark
 
Downwind

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Posts: 2333
Posted: 12:15am 11 Jan 2014
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Is it correct you have a Inverter generator.

Mine and M Del comments have been more to a standard generator and not an inverter type generator.

Where inverter generators are not so RPM/50hz dependent.
Sometimes it just works
 
M Del
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Location: Australia
Posts: 155
Posted: 03:15pm 11 Jan 2014
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Hi guys, as it was explained to me by the guy in the service centre of a large local tool wholesaler (actual tool shop not big box joint) and confirmed by our eleco as we were considering buying some for bush use. The little ones are real quiet and beat having a diesel running just for lights all night.

Most little inverter chargers have an economy mode but there is difference in cheap and expensive machines.
In a quality/high priced unit (eg genuine Honda) if running in economy and a large load is detected the inverter/genny will kick into normal mode and power up to handle the load. We trialled a 1kva Honda for a while and it worked as stated, but after running the large load you had to manually turn it back to economy.

But with a cheap unit you have to manually turn it over to normal or you will have the problem that Domwild is having.
Think of it as limp home mode in a car where you can do 30-40kph if lucky and don't even think about a hill or you will stop.

cheers





Mark
 
domwild
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Joined: 16/12/2005
Location: Australia
Posts: 873
Posted: 07:39pm 11 Jan 2014
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Yes, my 909 3300W is an inverter unit. Masters in Perth used to sell them for $650 but I bought the shop demo unit for much less. I suspect they may have had many problems with calling it a key-start model as the SLAs are giving problems as forum members have found out if the batts are too long in the box and they are not being recharged, how could they be?

Masters let it be known they are not going to buy any more?? Do not know if they just mean this model?? Masters is full of 909 gear.

If you want an equivalent Honda you pay $1,000 more so I shall not complain too loudly. Any idea what sort of a surge protector should be used as it says I should use one? I do not feel I should have to buy a $60 power board with surge protection if I can avoid it via friendly advice from someone with a black belt in electrickery!
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill
 
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