(Part 3) Top products from r/batteries

They usually don't state that information so it's honestly a guessing game

It doesn't have to be those model of cells but you're definitely going to want something with the power output of those cells(25-35amps) don't confuse that with the capacity of the batteries which in this case are around 2500mAh. Chances are your drill battery pack uses 18650(18mm diameter by 65mm and 0 for cylindrical)battery cells which are pretty easy to find but becareful of fakes they're dangerous, I can help you identify if needed. Assuming you have the tools already the battery cells are going to cost $20-25 all together alone so I'm not quite sure if it's worth the time vs just buying an off brand (albeit good rating) battery pack.

For example this off brand battery pack uses very high quality 3,000mah LG HG2 battery cells.

Powerextra 18V 3Ah Lithium-ion Replacement Battery for Makita Cordless drill 194205-3 LXT-400 BL1830 BL1815 BL1835 https://www.amazon.com/dp/B00CXO5X9Y/ref=cm_sw_r_other_apa_PPAnxbMF091EJ

I can assure you there would be basically no advantage buying original makita packs over buying these battery packs(as far as the cells go) the actual quality of the pack might be a different issue. The cheapest you're going to find those cells for are around $5 and they have have 5 of them. So you're honestly better off just buying a brand new pack.

NI-MH batteries are around 1.2 volts per cell. A battery holder like the one I linked will wire them in series. So the 10 cells together will give you about 12 volts.

Here is a link to some battery holders that already have lead wires attached.. If you fill them with 10 NI-MH batteries, you can just wire to the leads for your 12 volt connection.

To make this work, of course you will need some good NI-MH cells. I've been really happy with Eneloops like these though I'm sure others in this sub know more than I do and could give you other good recommendations.

You will also need a charger, and preferably one that can handle at least 10 cells at a time. I've had good luck with this one from Tenergy, but again you might want to ask this sub for recommendations. There are lots of people on here that have more experience that I do. Good luck with your project!

After looking around some, I'm not sure there are primary 18650's. I also don't really see the motivation for a primary here. You haven't said if you want to save money, weight or what. Is the goal to throw them away when you're done? Like /u/cosmic_butter_cpu said, a solar charger with some rechargeables would be the best option. Here's a smart adapter which is commonly bought with solar cells (if you look at the "commonly bought with" section).

yes absolutely.

you may lose some life if you don't use matched cells but this is COMMON

RC Car battery packs (before lithium) worked this way.

you had 7 and 8 cell sub c cell packs. any of those chargers will charge your pack just fine.

charge at 1amp should be plenty safe a decent charger will auto detect full and stop.

do be sure to charge them separately the first time then discharge and charge "as a pack" only so the cells don't mismatch.

this will work just fine

http://www.amazon.com/gp/product/B003MXMJX8/ref=pd_lpo_sbs_dp_ss_2?pf_rd_p=1944687602&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B002PECWXC&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1SVXNCYT30XW7S7HEZA8

and it is cheap too. you should be able to get away with a 2amp charge if your using 2amp hour or better cells.

>with 75min reserve capacity... yet it only has 66min reserve capacity.

That smells like an advertising gimmick, if you test it after charging the battery to 15.0V or 14.5V down to 10.5V then obviously you get longer service, I wouldn't worry too much about that.

>Whats the best deepcycle 12v battery i can get.

You could look at the size of the battery tray under the hood (and available height) if a larger battery will fit, that should improve reserve capacity.

Another thing to look at is the number of charge/discharge cycles, ...and 300+ discharge/recharge cycles, cheap to buy could mean expensive to replace often.

Some batteries will show a C rating. That's the charging rate relative to the battery capacity.

For instance, I have a 7.2Ah battery that mentions a 0.3C charging rate. That means that I should charge it at 7.2Ah * 0.3 = 2,16 amps.

15 amps is probably too much for a 18 Ah. From what I see online, a certain battery mentions 5.4A max. Yours should be around that, too.

Plus, most modern deep discharge SLAs are AGM (Absorbent Glass Mat) and will need a bit more voltage than car batteries. Mine should be charged at 14.7V.

For that reason, I would suggest using a charger designed for AGMs. I have this one that can charger both my car and my AGMs and it works well.

Feel free to ask any question if you have some :)

Consider the Battery Tender Junior:

https://www.amazon.com/dp/B004Q820UK

>Battery Tender Solar Controller allows you to convert an existing solar panel into a solar charger using Battery Tender patented Super Smart Charging Algorithm. Usable input range between 5-45 Watts.

>I'm more concerned about matching the output of the original batteries.

Voltage depends on battery chemistry. NiMH will always be 1.2v nominal (i.e. 0.9~1.4v) per cell, so swapping them for modern rechargeable-NiMH's like Eneloops isn't a problem. Plus, even though the two cells in the pack are in series, 2.4v is very low for an audio/RF circuit, so its probably regulated by a dc-dc boost converter which usually come with a wide input-voltage range.

>If I put in 2500mAh batteries in a device expecting 2100 mAh, does it just sip what it needs and last longer

Yep. mAh is the indication for capacity, it doesn't actually say anything about the maximum current you can draw from a cell (that is indicated as its "C-rating"). Any non-trivial* electronics design will have a self-regulated current draw, so in the same way a computer won't suddenly pull 1000 Watt when you upgrade it's power-supply from a 300 Watt model, having batteries with higher C-rating or bigger capacity won't do any harm.

* With trivial I mean, for example, a red LED stuck on a 3.3v coin cell, which relies on the (high) internal resistance of the battery to limit its current to ~25mA. Using the same LED with 2 AA Alkalines in series (3v) would fry the LED, probably instantly.

Unfortunately the one I use is sold out at Amazon.

Titanium Smart Fast 16 Bay Ni-MH AA/AAA Battery Charger AC 100-240V + DC Adapters MD-1600L https://www.amazon.com/dp/B005UNPM3M/ref=cm_sw_r_awd_7KB9ub1TAAHJA

It's a great charger, shows each individual cell, has a discharge cycle. I haven't put it through a ton of use, but it has held up very well.

I recommend that you use 6 x AA NiMH cells, use them in the battery holder, as is.

Then buy a 7.2 V charger for NiMH batteries, add a connector and use it to charge your toy.

Here your go: only 1kwh https://www.amazon.com/dp/B004LPIYJ4/ or here is one with 3.2kwh https://www.amazon.com/dp/B01M61VLBZ/

He means to use these batteries and these converters.

Normally I'd make the case for rechargeable AA cells but those get very expensive for occasional use electric candles.

No, sorry. That wouldn't be enough to replace the energy used by a straightener unless you wanted to wait a week between uses. You want one of these: https://www.amazon.com/Conair-Cordless-ThermaCell-Inch-Straightener/dp/B007ZN5CC6

> 4x AA NiMH

Are these rated at 1.2V? Doesn't specify on the page. If that's the case, then I would need 7 of them to make it over 7.5V.

Just curious though, what's wrong with this one?