Lead Acid Battery Care

[Dave Liquorice]

Power cut this afternoon about 1700, text from DNO saying High Voltage fault off until 2030. Drag out generator, battery utterly flat. Pull started the (diesel) generator and power came back about

1900. Even after that couple of hours the battery didn't have enough umph to engage with the starter ring. It sits at about 11.5 V, one end cell looks a bit low one electrolyte and the case at that end is slighly bulging. Battery is kept on genset in the unheated garage so may well have got frozen. Perhaps not last winter but in 9/10 or 10/11 it got below -10 C without much trouble.

Pretty sure the battery is a gonner and I'd not trust it anyway for a semi-critical system. It'll be replaced but how to keep the new one in good condition for years with it doing basically nothing. The genset might called into service in anger once a year and occasionally if it's "a while" since the last in anger run I'll fire it up for a couple hours powering a fan heater to make sure it still works.

So how do you molly codle a lead acid battery that doesn't get much use? Keep it somewhere a bit warmer? Would have to have an easy to use plug/socket capable of carrying the starter current. I don't want to be fiddling about reconnecting the battery in the middle of the night, by torch light, whilst being battered by a gale and driving snow...

Don't fancy the idea of having it on a charger all the time, even one of the clever ones that drop to a "float" charge. I suspect that rate will still be too high and dry the cells out over the months.

I have got a small PV panel that I had used with it before but wasn't convinced that the dark/low light leakage drained more from the battery than was put in by the PV. The PV panel was in a north facing window so not ideal. To get south facing wuld require a rather long cable run, proably not far short of 50m by the time you've gone round things.

Any other suggestions?

[Blano]

Surely there must be really smart chargers around for just that situation ?

[Mike Tomlinson]

En el artículo , Dave Liquorice escribió:

A diode in the leads from the PV panel to prevent reverse current flow?

Think you're on a loser with that one.

How about putting a smart charger on a timer, so that it runs for only a couple hours a day and doesn't dry the battery out by running all the time?

Re. preventing the battery from freezing, maybe put it in one of those polystyrene cool boxes, cut notch(es) in the lid for the cables? This sort of thing:

age/AUT1175_2.jpg

[Brian-Gaff]

Would not a simple silicon diode stop discharge though the cells? Admittedly ou would need .6v extra from the cells, but.... Brian

[Dave Liquorice]

The PV Panel already has a diode. Pretty sure I measured the leakage and decided it was significant, FSVO "significant". I can't say I can support that idea now, the specs for the 1N400? series of diodes give a leakage of 10uA max, or 0.08 AHr/year...

[Dave Liquorice]

Possibly not as the current is low (1.5 W @ 12 V = 125 mA max) so volt drop is also low (0.125 V per ohm)

That is an option if a suitable charger can be found. If buying a charger one may as well try and get something designed to do the job properly. I suspect that might not be easy.

Build something? Lead Acid are supposed to constant voltage charge with the volatge set to provide bulk or (frequent) cycle float rates. reducing the voltage to a level such that the current is very low (<

10 mA?) starts me thinking that slight battery changes or even just temperature change is going to affect the current drmatically. Would a limited constant curent supply be better and pure DC or pulsed?

Not easy to retro fit around the battery tray on the genset, there isn't much clearance from battery to frame/alternator etc. Also with the garage at -10 C for a week nad near freezing for a month or so either side I supect everything will get pretty cool insulated or not. How much warmer would the watt or two from a float charger keep the battery in such a box?

[Andrew Gabriel]

Schottkey diodes are normally used in this case - they can be down to

0.2V forward voltage drop.

[Harry Bloomfield]

Bringing it up to full charge once per month I find is the best compromise for a battery which isn't used or rarely used. That what I now do with the caravan battery. My last one, I left on 13.8v permanently and it only lasted a few years before it needed replacement, it had gassed itself dry.

I now just connect the battery every month to 3 months, to bring it back up. I also ensure I leave it on charge longer than normal following use of the mover, just before a trip, or on return from a trip.

If you can find one, a plug in timer which can be set to come on once per month for a couple of hours, would be ideal.

[damduck-egg]

Think out of the Box, Get an old Field Marshall tractor to drive a generator, makes sure it has winter Diesel in. Field Marshalls came with a cartridge start so no batteries to worry about, insert cartiridge and whack with hammer. As an added bonus everyone miles around will hear it running and know you are comfy.

G.Harman

[Mike Tomlinson]

En el artículo , Dave Liquorice escribió:

True, but last time I looked 50m of cable isn't free :)

store it on the floor next to the gen and run longer cables?

Using a trickle charger on the battery will warm it up slightly. If you used a charger on a timer, warming up the battery stored in a poly case may be enough to prevent it freezing.

It wouldn't, but the battery itself will warm slightly during charging, so if you could insulate it that may be all you need to prevent it freezing.

Just some ideas.

[Huge]

That bit I *can* answer; Anderson Connectors.

They're hermaphoditic (so the connnectors are all the same, you don't need to buy a 'male & female'), polarised (so you can't connect them the wrong way round) and can carry 50 Amps. Very widely used in motorsport (which is where I came across them). I have them on my race car for jump starting.

[tony sayer]

In article , Dave Liquorice scribeth thus

Time to change it. A good battery should be able to turn the engine over after a couple of hours of charge.

How do car batteries get on in cold countries being outside all the time;-?.

We have a genset thats almost under the same conditions, thats to say lives outside in a sort of outhouse. We float charge the battery with a

13.8 volt power supply that IIRC delivers around 5 amps at most made with a LT-1083 voltage regulator.

Works fine and has done so for around 4 to 5 years now since fitted. We now and again just fire the genset up to see if it works and it does, but it might be months between those events but the battery has never failed to deliver and that must be some 8 years old or thereabouts now....

FWIW..

We made up a very effective auto-start and changeover system using these modules which aren't that expensive and do work well having been used in anger around three times in as many months with a duff overhead supply!..

[Mike Tomlinson]

En el artículo , Huge escribió:

APC use them on their UPSes where the batteries have a cable loom to combine them in series and/or parallel. The Anderson connector is used to connect the battery pack(s) to the UPS.

Shown here:

02.jpg

[Huge]

Indeed, but they are the 'small' 24 amp ones and won't take starter motor current.

[Tim Lamb]

In message , [e-mail] writes

Point of order.. My tractor diesel supplier says there is no such thing as *winter grade* rebated fuel now. I used to avoid buying fuel after April and before October but he says this is no longer necessary.

They also had an arrangement where you screwed a piece of lit corrugated cardboard into the engine and then cranked a starting handle.

[Andy Burns]

The bigger UPSes (1400 and 2200 non-rack versions at least) use the larger SMH SY50 Series aka Anderson SB 50A connector, I don't know if SMH bought Anderson or vice-versa, but the names seem to be interchangeable now.

[Huge]

I have a SmartUPS 2200. It uses the smaller connectors.

Anyway, this is all irrelevant. Dave needs the 50A ones.

[Andy Burns]

Rackmounted version using the (8?) small batteries as shown in the newegg image?

Both my SU2200's and my SU1400 (all non-rack) use the big connectors, and NP18-12B batteries

[RayL12]

Actually, cycling is what me and a fiend decided to do with his system The details are lost now as this was the early 80's but, we designed a switching circuit based on low voltage and temperature and, a series of random cyclic charge and discharge.

We discharged into a heater blanket he made from fibred sheets which encased the batter sides. No great heat was produced but, it did reduced the bitter cold, some. I might add, this was occasional as, I am talking North West England. Nothing as dire as some places.

Similarly, you could get a mains plug with inbuilt timers. Find a circuit with a double poled relay switch which will either be charging or discharging such that the battery is always cycling?

...Ray.

[RayL12]

Time for me to change websites after reading the Ebay listing as 'Pam Anderson Connector' see ya'll in five minutes.

...Ray.