Equalising

[nicknorman]

 

 

Good call Nick, except that I'd need two of them in series and I'm not sure that pulse charge at the start would necessarily synchronise!

Oh yes I keep forgetting...

[MtB]

Probably your age...

 

[MtB]

 

Just downloaded the user manual, it does rather stress that this power supply should never be used for battery charging and that device damage might occur. Suppose I could connect via a big diode, but it would need to be on a heatsink.

 

..............Dave

 

 

Well they would say that wouldn't they?

 

Battery charger manuals usually say don't use them as a power supply too, don't they!

 

One point not raised so far regarding (mis)using power supplies for battery charging is the power factor. Sterling go to great lengths to get the PF approaching unity but PS manufacturers will feel no such need. A PF of 0.5 is quite likely I'd say with the consequent excessive consumption of petrol.

[nicknorman]

 

One point not raised so far regarding (mis)using power supplies for battery charging is the power factor. Sterling go to great lengths to get the PF approaching unity but PS manufacturers will feel no such need. A PF of 0.5 is quite likely I'd say with the consequent excessive consumption of petrol.

Obviously PF could be an issue for a big bench power supply, however I think it would be an unreasonable generalisation to think that all bench power supplies have a poor PF. I'd be surprised if they didn't all have some degree of PF correction these days. I just checked my own bench PSU (maplin switch mode) and it quotes a PF of 0.9. Thus in my survey of 1, 100% of BPSU's have a PF of 0.9!

 

I have a vague recollection that CE has some constraint on PF although I might have made that up!

 

Edit: no I haven't made it up EN61000-3-2 requires PFC for devices plugged into the mains that draw over 75w. Lots on the internet about it, e.g. http://electronics.stackexchange.com/questions/47026/is-pfc-compulsory-for-ac-dc-converters-75w-and-above

 

Or here https://www.epsma.org/PFC%20Guide_November%202010.pdf

Edited January 11, 2017 by nicknorman

[mross]

My Chineses BPSU claims an efficiency of 85%, no PF quoted.

[MtB]

Well that's encouraging, but I seem to remember that nice Mr Sterling makes quite a deal about the PF on his chargers being high. I think I can live with a PF of 0.9 for equalising.

 

Hypothetical though if my current pump thing turns out to be reliable!

[mross]

Yeah, my BPSU is 0-30V, 0-10A and will run from shore so the loss will be 16v x 10A 15% = 24W. I have not tried it yet. Cost only £45.

Edited January 12, 2017 by mross

[MtB]

Yeah, my BPSU is 0-30V, 0-10A and will run from shore so the loss will be 16v x 10A 15% = 24W. I have not tried it yet. Cost only £45.

 

 

I'm just wondering about buying two of those and connecting them in series so I can get 32V still for under £100!

 

Either that or equalise half my bank at a time...

[mross]

Mine was http://www.ebay.co.uk/itm/282164133756?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

Posted from UK, not China. Model number QW-MS3010D.

 

Suggest you only get one for now as they are cheapies. I asked the vendor if I could use it to charge a lead-acid and he said yes.

[nicknorman]

With bench PSUs I think the issue for charging batteries is when they are first connected with the supply off. There are normally large capacitors on the output that suddenly get a very low impedance source of current - a massive current surge to charge the caps. So I wonder if it would be better to turn the psu on first, set the voltage to roughly the current battery voltage, then connect the battery up, then set the required charge voltage. More normally one would of course connect the charger before turning it on.

[mross]

There is a youtube review here

[cereal tiller]

Mine was http://www.ebay.co.uk/itm/282164133756?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

Posted from UK, not China. Model number QW-MS3010D.

 

Suggest you only get one for now as they are cheapies. I asked the vendor if I could use it to charge a lead-acid and he said yes.

Thanks for the link,have just ordered one

 

My main battery bank is 6 105 a.h. 12 volt Trojan

 

The Bank can be split with a rotary switch,the Idle bank could be charged from my 30 AMP. charger first then Equalised with the Bench power supply

 

CT

Edited January 12, 2017 by cereal tiller

[mross]

Just remember to switch the PSU on before connecting load and to disconnect before switching off. Otherwise, you can destroy the unit. Also, it produces voltage spikes when you turn it on.

[cereal tiller]

Just remember to switch the PSU on before connecting load and to disconnect before switching off. Otherwise, you can destroy the unit. Also, it produces voltage spikes when you turn it on.

Will do,the Spikes should be okay as the bank being Equalised will be off line

 

When equalising is completer The banks can be swapped over

 

 

CT

Edited January 12, 2017 by cereal tiller

[cereal tiller]

Will do,the Spikes should be okay as the bank being Equalised will be off line

 

When equalising is completer The banks can be swapped over

 

 

CT

PSU arrived this morning,connected it to the Battery bank which was fully charged

 

Settings were 15.5 volt at 7 AMPS current,the Batteries were isolated from any Loads

 

After one hour it went pop and had the classic Fragrance of Kentucky Fried Shellac coming out of it

 

Will return it

 

CT

[mross]

bummer! let us know how you get on with the return. Will you try another or ask for refund? I hope to test mine next week.

[cereal tiller]

bummer! let us know how you get on with the return. Will you try another or ask for refund? I hope to test mine next week.

Will do,going for Refund

 

CT

[nicknorman]

I didn't comment at the time but I did think that PSU looked pretty old fashioned and there are lots of warnings and caveats about how to use it so it won't blow up - in other words it is not well protected, reminiscent of early SMPSUs.

[MtB]

Will do,going for Refund

 

CT

 

 

Will you have to send it back to China?

[cereal tiller]

 

 

Will you have to send it back to China?

No,it was flom urited king dom.

 

 

CT

[Col_T]

Mornin' all.

 

A quick question, or two:-

 

Do sulphate crystals start forming as soon as a fully charged battery is taken off charge, as a by-product of the lead acid battery self-discharge phenomenon? Or perhaps that should be does leaving a battery to self-discharge cause it to sulphate?

 

I've read on other posts that leaving a battery on float for an extended period of time makes it lazy, in that it discharges overly quickly for a couple of cycles before reverting to expected behaviour. Anyone got any idea why that might be?

[cuthound]

Mornin' all.

A quick question, or two:-

Do sulphate crystals start forming as soon as a fully charged battery is taken off charge, as a by-product of the lead acid battery self-discharge phenomenon? Or perhaps that should be does leaving a battery to self-discharge cause it to sulphate?

I've read on other posts that leaving a battery on float for an extended period of time makes it lazy, in that it discharges overly quickly for a couple of cycles before reverting to expected behaviour. Anyone got any idea why that might be?

The sulphate crystals begin to form as soon as the battery is taken off charge.

 

They are the result of the sulphuric acid becoming weaker as the battery discharges, (including self discharge) as the sulphur is transferred from electrolyte to the plates.

 

My understanding of why leaving a battery on float makes it lazy, is because tiny bubbles of hydrogen from the charging partially insulate the plate from the electrolyte. The bubbles disperse when the battery is used, making it appear as though it has regained capacity.

 

Edited to replace a missing letter.

Edited January 17, 2017 by cuthound

[Col_T]

Thanks for that, and apologies for 'borrowing' the thread!

[peterboat]

Good afternoon Mike,

When your whispergen is installed it may save your issues. Mine last night when I hit the start button was charging at 15 volts for about half an hour it then cut back to 14.2 then went into float. my boat has been empty for a week with just the fan on the composting toilet running so solar alone had the batteries at 12.6 volts. you will have to scale up for your 24 volt version but i am sure all will be well in your battery world soon

[dmr]

Mornin' all.

 

A quick question, or two:-

 

Do sulphate crystals start forming as soon as a fully charged battery is taken off charge, as a by-product of the lead acid battery self-discharge phenomenon? Or perhaps that should be does leaving a battery to self-discharge cause it to sulphate?

 

I've read on other posts that leaving a battery on float for an extended period of time makes it lazy, in that it discharges overly quickly for a couple of cycles before reverting to expected behaviour. Anyone got any idea why that might be?

 

Sulphate is a normal and intrinsic part of how a battery works, rather than a disorder. As the battery discharges the lead oxide is converted to lead sulphate by combining with the sulphuric acid, and this is why the acid gets weaker/specific gravity gets lower. On recharge the lead sulphate is converted back to lead oxide. However this lead sulphate slowly crystallises/hardens so all the time lead sulphate is present (less than full charge) it is getting harder, and so the longer the battery remains at less than full charge the harder it is to recharge it. After a few weeks it won't recharge unless we apply a higher voltage (equalisation) and after a long time the stuff is so hard we can't recharge at all and the battery is "sulphated".

 

..............Dave