I'm about to implement some garden stuff involving a couple of
120HA leisure batterys - and I need to charge them (there will be solar, eventually, but for now they'll get wheeled up to the house to be charged)
Just one at a time though - So looking for something that'll do and preferably charge them overnight and not mind if I leave it on charge for a few days, so something with a bit of cleverness in..
I've looked - found loads online with wildly varying prices, but any recomendation to use or avoid would be appreciated.
Solar - 240 AHr - done the sums? To get that sort of energy from PV means they ain't going to be small or cheap. Wheel barrow to a mains charger in the garage may suddenly have a lot more appeal. B-)
To charge over night (10 hrs) it's going to be quite a chuncky mains charger as well, 12+ amps required... Can't help on a particular charger but there is a chip that does all the "clever" stuff, polarity, too flat, automatic "bulk" then "float" voltage switching, etc so you should be able to find something.
Both Lidl and Aldi do a small SMPS smart charger for about 13 quid. It will certainly charge a car battery overnight - a larger one may take longer. It is happy to be left on as it switches to a maintenance setting after charging. It's basically incredible value. (I have one built in to my old car - at that price it seemed the logical thing to do)
Lidl had them recently - and my local branch had a few left at the end of last week.
They charge at 3.8A max, if they're the same as the ones I bought a few years ago. (Also have a 0.8A reduced setting for small batteries.) At 3.8A, they'll take 36-48 hours to charge a 120Ah battery. The chargers automatically switch to trickle charging when charged, but do test what voltage that is and check with the battery's datasheet. Regularly overcharging will significantly shorten the battery life.
Yes - I've done the sums. The plan isn't to deplete the batteries completely through the day/night and not use the, every day either. This is just a worst case/winter scenario.
All part of a plan to provide some lighting and a bit of work "stuff" in the summer house for a couple of hours a day at max. and some garden cameras taking stills every now and then.
It's all controlled by some smarts I'm in the process of building myself, I'm just being lazy about making my own charger.
Thanks,
Gordon Ps. Garden is 60m from house and running mains down to it would involve a lot of armoured cable and wayleave over 2 other properties )-:
Indeed. You have to be seriously off grid before solar PV becomes at all cost effective. Most PV powered devices round here - mainly radar active please go round the bend roadsigns are invariably dead in the water on cold frosty winters mornings when they might do some good.
They are perky enough in mid summer though when not needed.
Wind power might be a more cost effective solution.
Batteries will mostly tolerate a some of abuse on a C/10 charge rate but moving them around will be a royal PITA.
Strangely enough I'm not that interested in it being cost effective. It's a combination of a "can I?" type of experiment and "wonder if it might work" type of thing. I don't care at this point if I never save money on it because that's not the aim. I'm considering it part of my hobby and who knows what I've spent in the past on my hobbys...
For me, if I have to wheel a battery up to the house every time I visit the garden, then it's a fail, but anything less than that is a bonus.
I've never seen CTek get anything but very good recommendations - we've got one (MXS5 - 5A) in our camper, and it does the job required just fine. Clever enough that it'll figure out if the battery needs a gentle recondition, as well as the usual trickle/maintenance mode. Varying sizes, depending on what sort of charge time you want.
Cleverness? Surely with lead acid if you get the voltage and current right the current reduces to practically nothing when they are fully charged. I used this technique for years on a lawnmower battery I used to run stuff from back in the 80s. Brian
And from having used armoured cable the cost brings tears to the eyes and even quite chunky stuff seems to lose a lot of volts as well if you use any kind of current. Brian
I had taken "leisure batteries" to mean SLA where I'd understood a different profile was needed for a full charge and long life: constant current > constant charge voltage > lower float charge. No?
Seriously you should consider wind power rather than solar PV then.
I considered solar PV for my greenhouse irrigation system which in the end uses a 7Ah battery recharged once a month in summer but it was way more cost effective than a solar PV array powerful enough to drive a pump. Most "solar fountains" are pathetic but the pumps in them are actually really rather good when on a decent power supply!
You will need a charge controller to allow the summer charging regime to avoid damaging the battery if it is meant to work at all in winter.
This isn't about being a greenie/off-grid warrior/saving money, or anything else. It's about a hobby project to add a bit of comfort to the garden and maybe make it a place I can do a couple of hours work in (I mostly work from home). Provide some LED lighting, a Wi-Fi link to the house and possibly charge a mobile phone. I have a river at the bottom of my garden and I've even considered that, but there isn't enough fall or depth in summer to make it worthwhile. I've even considered using mains water - unmetered, high pressure - 9 bar here, but that just doesn't feel right. The 2 x 200w panels I have planned for the shed roof will be sufficient for what I want, but in the mean-time, wheeling them to the house once every few days will be fine.
I have 2 batteries, the plan is to use one until done, then the electronics auto switches to the 2nd and goes "beep" to tell me one needs charging. Every device connected to the system has individual power control and will be powered down when not in-use. A bit like your mobile phone which turns off peripherals when you're not using it to extend the battery.
I leave the house, push the "Garden On" button, a signal is sent via a separate low-power radio link to the garden to turn on - which it starts to do, then by the time I arrive, enough is booted & running for me to do something.
A "Water Feature" is on the cards at some point - and it may well be a "Solar" one, but with the panel & batteries removed and plumbed into the shed supply. I've done that already for the fairly lights - some are stupidly cheap to buy with a solar panel & little internal NiCd and easy to remove and hook into the system.
I think I've found a suitable solar one designed for dual-batteries. Just looking for a decent mains one for now.
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