Small battery options?

[oxford]

I am running a power dynamo ignition currently with no battery.  I am also using a electronic tach/speed which is apparently not happy with the voltage coming off the regulator(not a consistent 12v) so it seems like I will be needing to add a battery.

What are some good options for a small battery?  I have looked at the antigravity lithium battery's and they would probably fit the bill.  Any experience with them?

[sav0r]

I know nothing about that charging system.

That said, I run a 5k mah RC battery. I've got 5 years on it. With LEDs it's been more than fine. I have the HPI kit and plan to run the same batter with it.

I'm on mobile but can provide a link to battery if you are interested. The antigravity battery has no advantages, IMO. It's just way more expensive.

[oxford]

I'll take a link to what you are running when you get a chance.  What is your headlight draw?

[sav0r]

https://hobbyking.com/en_us/turnigy-5000mah-4s1p-14-8v-20c-hardcase-pack-1.html?queryID=6c9aa0174264e5fb15ebc80501db8f14&objectID=74826&indexName=hbk_live_magento_en_us_products

I've also run half that mah without issue, just don't leave the ignition on (with excited field). The charging system will blow the fuse if I run a 5 amp fuse. If I run total loss, a 5 amp fuse is fine. I run all LED's.

I can't remember what my headlight draw is exactly, I am guessing less than 2a (probably closer to 1a). I built it custom with an LED panel at the time (6 plus years back)... I do know that in modern terms my headlight is pathetic, though it's still better than stock...

The Turnigy is a really solid battery. I generally check it's balance twice a year. It's never out of range. Any reasonable modern charging system should be friendly. I've let it sit without use up 6 months and it never changes charge wise. My garage is only somewhat heated and I live in Pittsburgh.

I do recommend exercising caution with these setups. I worked up to it slowly...

[teazer]

Good choice.  I use a smaller 1,300 4S on our drag bike to run tacho and shift light.  The rest is a self energizing ignition and a bicycle rear lamp and that's it, but as you mentioned, it cannot be charged by the stock charging system.  Bench chargers are cheap and can also be used to balance the cells and charge regular lead batteries too.

BTW, if it goes completely flat, there's a good chance 2 or more of the cells will not come back from the dead, and you can guess how I discovered that.

I prefer the soft case options but they need enough volume because they expand more than one might expect.

And never hit the battery or throw it across the room.

[rodneya]

Im running a small sealed alarm battery, I think 3ah

[retaRD]

Im running a small sealed alarm battery, I think 3ah

I run these on every kickstart bike I own. 
They're a common, easy to find battery.
I use either 2.5 or 5ah size, and they're deep cycle so you can charge a phone or something off of them. 

[Dvsrd]

On my RD350 with Powerdynamo,  I use a Super B LiPoFe battery. Small and light, 450 g or 1 pound. Had it for nearly 10 years, no probs at all.
https://www.super-b.com/en/products/andrena-12v2-5ah

[m in sc]

Im running a small sealed alarm battery, I think 3ah

the last one i had in the white rd lasted 8 years.

[sav0r]

Here's the charger I use.

https://hobbyking.com/en_us/imax-b6-dc-charger-5a-50w-copy.html?queryID=&objectID=53604&indexName=hbk_live_magento_en_us_products_hbk_price_stock_2_group_0_asc

It's a great charger for the price. I know AntiGravity and some other places sell their balance chargers for like $100 or more.

There are some really nice batteries out there with onboard battery management boards, where they balance themselves. The alternative to that is to buy a battery management board from like Aliexpress and wire it up.

This is the 2.2mah pack I used very successfully. Keep in mind I run a wind mill rectifier and regulator (based on mark's F150 thread i think) of my own making, but it's all modern solid state equipment (and also very cheap).

https://hobbyking.com/en_us/turnigy-nano-tech-2200mah-2s-35-70c-lipo-pack.html?queryID=&objectID=30638&indexName=hbk_live_magento_en_us_products

[pidjones]

I used Turnigy batteries years ago in model helis. As with most from China, you are the quality control but theirs were as good or better than the high priced brands. Lots of othe good things on their site like high current gold plated disconnects.

I believe they have warehouses in Germany and USA.

[rodneya]

Im running a small sealed alarm battery, I think 3ah

the last one i had in the white rd lasted 8 years.

Only thing I dont like is the spade connectors

[retaRD]

Im running a small sealed alarm battery, I think 3ah

the last one i had in the white rd lasted 8 years.

Only thing I dont like is the spade connectors

That's actually one of the things I like about them.

[Dvsrd]

Im running a small sealed alarm battery, I think 3ah

the last one i had in the white rd lasted 8 years.

As for weight, even a 3Ah lead acid (agm, gel, etc) is pretty heavy IMHO.
If, say a 1 Ah LiPoFe battery was available, it would be more than enough to operate the relay for a Powerdynamo to work with stock ignition lock and kill switch, and it would weigh around 200 g or 6-7 ounces.

[rodneya]

I dont really think that the pound or so that my battery weighs really makes any difference. on my bike. Having a hunk of lithium under my nuts will bother me though. On a new bike with a modern charging system, maybe. Having to charge the battery when I get home with an external charger, way to inconvenient.
Somebody posted a while back  after a small lithium type battery went up in flames while he was riding. The damage was only minor as he pulled the burning hunk out and cooked his hand, but it could be a quick way to loose a bike.