NiMH Chargers

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gregmcc

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#124634 14-Jul-2013 19:51

I'm looking for a some what good charger, Currently I've got a couple of those Energizer ones that plug into the wall that charge up to 4 batteries for 8hrs at a fixed current, but now I'm looking for something that will actually condition the batteries and tell me if there is a faulty battery. I would perfer to buy from somewhere in NZ but purchasing from overseas is also an option.

So who can point me in the direction of something better than what I am currently using.

I only charge AA, and AAA batteries and the batteries are all energizer NiMH's.

timmmay

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#855464 14-Jul-2013 20:07

Maha, C9000 or C801D. Can write more ona computer, geekzone bites on a phone

sbiddle

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#855471 14-Jul-2013 20:21

Jaycar have always had a good range of chargers.

rhy7s

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#855504 14-Jul-2013 21:20

I use a LaCrosse BC-700 with a few different brands of low self discharge AA/A cells, haven't had any issues. EDIT: Actually, occasionally I have to give a really dead cell a boot in a dumb charger before it will be recognised.

jtbthatsme

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#855599 15-Jul-2013 08:42

I'm using one from Jaycar PowerTech Plus it's a rapid charger and takes about 15 - 30 for a full charge will flash when the cell not working but this is not a true indication of it truly being dead. You can move it to one of the other charge slots and it will often pick up the battery. I use Duracell rechargeables that I got from NZGameshop for about $12 per 4 pack for my own equipment (keyboard, mouse, remotes and Xbox 360 controllers) and have some cheapies I got from Ebay a few years ago (I think I paid about $20 - $30 for 48 AA) that mostly work fine 99% of the time.

I use the rule of if it's not picked up on one of the slots I will check to make sure the contacts are clean then try all other slots (obviously only if not picked up will i move on) and normally find most of the cheapies will get picked up. If they don't by the 4th then in the bin it goes.

As for the Duracell and the few Energizers I have never any issues.

Think it was $25 - $30 and as far as battery chargers go it's been the best I've owned a few branded ones including the Energizer ones and they've all died within 12 - 18 months should have kept receipts I suppose as when getting my free replacements I could've gotten a few extra batteries each time lol.

Jaxson

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#855615 15-Jul-2013 09:15

timmmay: Maha, C9000

What he said. I researched the begebers out of this several years ago and found this to be the top of the crop. The La Cross version was similar but lacked some features of the Maha.

Basically the C9000 allows you to fully discharge your battery and a rate you specify, and then recharge it fully at a rate that you specify. And then once charged it will provide a tiny trickle charge to keep the battery at the optimum charge until you get around to taking them out of the charger.

The unit also monitors the temperature of the battery too. They simply are very good. They also have standard defaults, so you can just chuck the batteries in quickly if you want to too.

The screen light is bright as, and the very early models occasionally burst into flames, but I honestly wouldn't recommend anything else. The cost is significant too...

rhy7s

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#855652 15-Jul-2013 10:12

Jaxson: Basically the C9000 allows you to fully discharge your battery and a rate you specify, and then recharge it fully at a rate that you specify. And then once charged it will provide a tiny trickle charge to keep the battery at the optimum charge until you get around to taking them out of the charger.

The unit also monitors the temperature of the battery too.

The LaCrosse BC-700 does all that as well. Basically you lose a couple of charge modes, the backlit display and some granularity over the C9000. For half the price I felt it was the better deal (it used to be less than USD$30 a lot of the time). A good overview is available from this Amazon review.

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timmmay

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#855676 15-Jul-2013 10:58

Maha and La Crosse are the best quality. Have a read up on http://batteryuniversity.com/ for details of how cells should be charged.

NiMH should be charged from empty in 2 hours, faster will reduce the battery life. 15 or 30 minute chargers are fine if you don't mind replacing them regularly.

I use the C9000 to break in and condition my cells, and the C801D to refresh them occasionally. I have 5 year old PowerEx batteries (Maha's brand) that are still going great, very near to original capacity. I had one cell fail recently, my first, they've photographed many many weddings with me, working very hard in those flashes.

Nety

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#856061 15-Jul-2013 19:08

Have the C9000 too. Very good charger and has brought many a battery back from almost death.

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Niel

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#856170 15-Jul-2013 22:54

Catweazle Trading on TradeMe sells Camelion brand and genuine, not fake like some other sellers. We use 3x 1h chargers for our church cordless mics and LSD (low self discharge) cells. Actually not supposed to fast charge LSD cells, but it seems to be okay for the past few years of charging 3 or 4 times a week.

The only maintenance required to get a high cycle life from NiMH is to fully discharge them once every 3-6 months. This is to break up the crystalline structure that forms in the cell due to normal use. It has nothing to do with "memory effect" (which was solved in the early 80's), it is a different reversible phenomena.

I'm in the process of converting my DECT phones to LiFePO4 batteries, the ultimate in safety and very long life with no noticeable self discharge. Just waiting for AA-sized cells to arrive from China. My 3 phones have been running one set of Camelion LSD NiMH cells for about 6 years and only now showing loss of capacity. I would charge them once a week and never leave them on charge for more than a day as over charging is what causes capacity loss. This equates to about 6 year x 50 weeks = 300 cycles, which is what you can expect from NiMH. Now LiFePO4 is getting cheap enough to make it worth modifying the charging cradles for 3.45V constant voltage float charging and leaving the phones on charge (cycle charging is 3.65V, float is 3.45V).

To get back to your requirements, the only way to detect a faulty battery is to test it with a battery tester which does a full discharge and charge cycle. There are many available in the RC hobby circuit, we actually use a few at work as they perform well but expect to pay $150 and no convenient battery holder.

The Camelion 1h chargers we use at church have a refresh button that will slowly discharge the cells over about 20-30h (to break up the crystalline structure) and then do a full charge.

If you normally charge your NiMH cells in a product (e.g. a cordless phone), then when new you should give them a formatting charge which is a slow 0.1C charge rate for 24h using a dumb charger. This will slightly reduce the life of the cells, but it equalizes them so that when you use them (in series) they all reach discharge level at the same time and they all reach charged level at the same time. If not equalized then one cell will always get over discharged and another will always get over charged.

You can never have enough Volvos!

timmmay

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#856230 16-Jul-2013 08:04

Neil, interested to hear how your conversion goes. Is the charging technique for the old cell chemistry compatible with the Li... cells?

The C801D has a refresh (ie discharge/recharge) function. The C9000 also has a break in function, which charges the cells, discharges fully, then pumps in the capacity the cell is meant to have not just what it wants to take. It monitors the cell temperature to make sure it doesn't oveheat. I suspect it then does a refresh charge afterward so it can tell you the actual capacity. This helps initialise new batteries, and recover old ones. I do it on all new batteries, and every year or two on all my batteries. It takes 3 days per set of four cells.

I may have the details slightly out, jetlag.

richms

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#863223 21-Jul-2013 20:51

For all my low drain stuff I just buy a tray of 48 or 60 alkalines every couple of years for $15 or so.

Other than that, in stuff that doesnt last as long I use my LaCrosse 700 to charge. Never bothered with the conditioning, use the discharge to see capacity and if its low just move the cell into the probably stuffed pile.

Richard rich.ms

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timmmay

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#863239 21-Jul-2013 21:14

A refresh does help, and a conditioning cycle really can help recover dead cells. Cheaper, and better for the environment, these things are full of all sorts of stuff you don't want getting to the water table.

richms

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#863246 21-Jul-2013 21:23

Its a time taken, charger unavailable vs cost of more cells tradeoff. The half stuffed ones still work ok in flashlights etc, usually it seems they just start to have massive self discarge which the recovery on the charger never has sorted out.

Richard rich.ms