sugestion for a nimh/16850 battery charger for the car

hammerjoe · Nov 28, 2015

I went out for a caching adventure today and grabbed a case with 8 pairs of batteries and when it came time to replace the pair in the GPS I dicovered that all of the ones in the case did not work...

I felt like I was caught with my pants down.
So I need suggestions for a battery charger that works good in the car and doesnt cook batteries. I think that a 2 slot charger is enough as I would only use for an emergency like this.

I am confused why the batteries would be discharged to this extent. They are LSD batteries (couple of black amazon, and some rayovacs).

They were charged on the Opus 3100 v2.1 a few weeks ago and were not used for a couple weeks.
I am recharging them right now in the Opus to see what kind of charge goes into them to understand the problem.

SilverFox · Nov 28, 2015

Hello Hammerjoe,

I carry an Energizer 15 minute charger. It runs off of 12 volts. In an "emergency" I don't mind the rapid charge rate. I just want to get my cells charged and get on with what I am doing.

When working with Li-Ion cells, I have a hobby charger that hooks up to the vehicles battery and can quickly revive those cells to get me through the activity.

Tom

Timothybil · Nov 28, 2015

The Nitecore i2, i4, D2, D4 chargers all have a 12 volt input, and will do both NiMH and Li-Ion. The Xtar VC4 has a USB input, and will work well with a car USB adapter as long as it puts out 2A. I use the MaxBoost. Very sturdy and reliable, two slots, 2.4A each slot.

NoNotAgain · Nov 29, 2015

I wouldn't waste my time attempting to recharge an 18650 battery in the field with any of the two or 4 slot chargers, even those that can operate off of a 12 volt source.

Running off of 120v AC, a spent 18650 is going to take close to 4 hours to charge.

The NiMH cells are your best chance at a fast rechargeable battery.

Gauss163 · Nov 29, 2015

Worth mention: a car's 12V cigarette/accessory outlet is unregulated (can be 9-16V or higher - see below), so it would be safer to regulate it to appropriate constant voltage, e.g. via a laptop car adapter (< $10 on eBay). Often chargers don't handle well large/quick input voltage fluctuations, e.g. iChargers were fried when users fed them 24V from two 12V server PSUs in series, and one PSU shutdown.

Below is what Wikipedia says on the accessory voltage range:

Wikipedia said:
A second problem is that nominally "Twelve-Volt" power in cars fluctuates widely. The actual voltage will be approximately 12.5 volts when dormant (less in cold conditions), approximately 14.5 volts when the engine and the alternator/generator are operating (more when cold), and may briefly drop as low as 5-6 volts during engine start.[7] When used, DC to DC converters will usually compensate for small fluctuations, but reliable power may not be available without an independent battery-powered uninterruptible power supply.

Rarely, more extreme cases of voltage fluctuation can occur when the car battery is disconnected while the engine is running, or when the car receives a jump start. When the battery is disconnected while the engine is running, a load dump transient can produce very high voltages as the built in voltage regulator will try to charge a discharged/non present battery (disconnecting the battery while the engine is running may also ruin the diodes in the alternator). A car receiving a jump start from a truck may be subject to a 24 V electrical system used in some vehicles.[8] Also, a "double battery jump-start" is performed by some tow truck drivers in cold climates.[9]

Equipment intended to be powered by the receptacle needs to account for intermittent contact, and voltages outside the nominal 12 V DC, such as maximum voltage 9-16 V continuously, or maximum voltage of 20 V lasting 1 hour, 24 V lasting 1 minute, and 40 V lasting 400 ms.[10] Protection component tolerance example ratings are +50 to -60 V DC.[11] Robust equipment must tolerate temperatures varying between −40 to +85 °C (−40 to 185 °F), plus possible high humidity and condensation of water.[10]

Timothybil · Nov 29, 2015

Gauss163 said:
Worth mention: a car's 12V cigarette/accessory outlet is unregulated (can be 9-16V or higher - see below), so it would be safer to regulate it to appropriate constant voltage, e.g. via a laptop car adapter (< $10 on eBay). Often chargers don't handle well large/quick input voltage fluctuations, e.g. iChargers were fried when users fed them 24V from two 12V server PSUs in series, and one PSU shutdown.

Below is what Wikipedia says on the accessory voltage range:

As Gauss163 noted, I originally posted this response inside the quote of his post. Thanks for drawing that to my attention.

This is where a charger with a USB input has the advantage. If one uses a quality USB adapter to provide power, the circuitry in the adapter should regulate the varying input voltage to a steady five volt output.

And yes, depending on a car charger to recharge your cells in a remote situation is not really feasible. If the situation requires it, a second set of cells should be included in the planning. That way one can go on with what one is doing while the first set is charging again. They may not be completely recharged when needed again, but they will have something in them to use.

Gauss163 · Nov 29, 2015

@Timothybil You mistakenly added your remarks in the middle of the quote from my post. Note that using a USB car adapter is a special case of what I recommended, i.e. employing a voltage regulator between the car's accessory output and the charger (in the special case that the chargers input votage is 5V instead of the OP's 12V).

NoNotAgain · Nov 29, 2015

IMO, using a 12 volt DC accessory plug for charging isn't a big deal.

If there were such high transient voltages present, the $1000 stereos and other electronics in most newer cars would be destroyed.

I just reread the Nitecore D2 manual, and the only thing they list about using DC voltage is that the charger requires 12volts DC and 1 amp of current.

A typical storage battery can have anywhere between 12.6 and 13.2ish volts after being charged while driven. The accessory port that stays alive with the key off draws directly from the battery. Transient voltage spikes are almost non-existent.

In this case, we're talking about a $20 charger, charging a couple of either NiMH or LiOn batteries.

If I were truly concerned, I'd use a true sine wave converter and an UPS to provide power.

hammerjoe · Nov 29, 2015

Are there any 2 slot chargers that can charge 2 batteries at 1A? I was looking at the VC2 but I see it can only do 500mA and the vc2plus can only do 1A in one slot.

The VC4 can do it but Its going to be a bit bulkier to carry around in the car.

Swamplite · Nov 29, 2015

I keep a 300w Triplite inverter in my truck at all times.Never used it for charging batteries but it does a good job charging my laptop so I am sure it would work with just about any charger you plug into a wall receptacle.

sugestion for a nimh/16850 battery charger for the car

hammerjoe

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