Battery Choice 10Ah Lithium vs 12Ah Gel/AGM

vagosofron

100 W
Joined
Dec 16, 2017
Messages
101
Sorry to hijack this thread, but which type of battery is better for a front hub 36v 500w motor?
A 36v 10Ah lithium battery pack, or 3x12v 12Ah gel/agm batteries?
This bike will be doing a 5 mile trip in total, almost 3 days per week.
 
vagosofron said:
Sorry to hijack this thread, but which type of battery is better for a front hub 36v 500w motor?
A 36v 10Ah lithium battery pack, or 3x12v 12Ah gel/agm batteries?
This bike will be doing a 5 mile trip in total, almost 3 days per week.

Lithium pack.
Lead acid battery is worth considering only if you can get it for free.
 
montieris said:
vagosofron said:
Sorry to hijack this thread, but which type of battery is better for a front hub 36v 500w motor?
A 36v 10Ah lithium battery pack, or 3x12v 12Ah gel/agm batteries?
This bike will be doing a 5 mile trip in total, almost 3 days per week.

Lithium pack.
Lead acid battery is worth considering only if you can get it for free.
Do you think 10Ah is enough for a 5 mile flat road?
 
10ah is fine for a five mile trip so long as you aren't expecting to be going 30 mph. If you are cruising in the 20 mph range and don't have severe hills, the 360 watt hours that pack holds should get you five miles up and back with about 1/3 of your power left. You can roughly figure about 25 watt hours per mile to be conservative. That 1/3 left over will offer some buffer as the pack ages, on days when have a strong headwind, or help you go a bit faster now and then. I'm a fan of having more battery than you "need." I'll tolerate the weight and to some extent, the cost.
 
Ah that's great, thank you! My trip is 10 miles in total, but on the way back, the road is slightly downhill, like 2% grade ( the same going uphill). So I will only need the motor half the way.
 
vagosofron said:
Ah that's great, thank you! My trip is 10 miles in total, but on the way back, the road is slightly downhill, like 2% grade ( the same going uphill). So I will only need the motor half the way.

If your pocket book can tolerate it and you don't mind the size and weight, you might consider something a bit larger so that you can have greater range on non-commuting "weekend" trips. Once you become addicted to riding your e-bike, you may find yourself wanting to use it more and to travel farther. :^)
 
I went with 36v of SLA's for 8 months. They were fine for about 1/2 of the amp usage. That is normal for lead batteries. So your 12 amp SLA battery pack is really only worth about 6 ah. A 10ah lithium battery can deliver about 8ah usable.

Around here we use the rule of thumb that goes like this. Ah x V = watt hours. 25 Wh per mile average.

So a 36v pack times 10 ah is 360 watt hours divided by 25 = 14.4 miles on average. 36v*10ah=360/25=14.4 miles.

Now I tend to use a bit more watt hours then others around here because in the city it is all about stop and go. Also, wind cold, dirt roads and any other efficiency dampening conditions will cost you miles. Your mileage will very.

A 12ah lead battery that can only deliver 6ah is really only a 8.6 mile battery, and, they will be warn out after a years time.

A lead battery charger will take 5 or 6 hours to charge. A lithium charger can go faster depending on your cells and bms and such. My 15ah LiFePO4 battery can be fully charged from lvc to full in 90 minutes if I want to use my fast charger. I am moving on to 12000 miles on my pack, they are showing signs of old age but still deliver 500+ watt hours even with the sag on the hills.

Still a good run though. Lead batteries would never be able to last like that.

Go with lithium. :wink:

:D
 
Ok, lead acid, or gel are a no go. I will build a lithium pack and when the project is ready I will post it. Thank you all for the tips!
 
The battery is the most important part of your bike. Buy more capacity than you think you'll need. Once you start riding, you'll want to ride more and more. You'll quickly start wanting more range, it's kinda contagious. Multistar Lipos, responsibly used and cared for are fantastic for the price. Catch them on sale at Hobby King and you'll feel like you're really getting a good deal.
 
I've read a lot about batteries and I keep reading. If I build my own, I will use vruzend caps, because I don't have a spot welder and I can't solder.
 
I haven't used the Vruzend system, however e-bike batteries are subjected to a lot of vibration. The Vruzend system has a lot of nuts to tighten. If you use that system be sure to learn how to use Loctite® Threadlocker or some similar product to make sure the nuts don't vibrate loose.

Also, be sure the Vruzend kit can handle your maximum amp draw. Or better yet make sure the kit can handle more then your intended amp draw.

This from their website:
We recommend that for best results, you limit the current draw of the battery pack you build with Vruzend battery caps to approximately 3.5 A continuous per cell. Current bursts of up to 7 A are acceptable, but for periods not exceeding 10-15 seconds. Higher current results in more waste heat being generated which can rob your pack of performance. That means that if you build a battery with six cells in parallel, you should try not to exceed about 20 A continuously with that pack, though bursts of higher current are ok. We’ve had some people do tests with higher current, but it usually isn’t worth the extra waste heat. Extremely high current can even be dangerous. Please be safe and don’t try to pull too much current from your battery cells – this is true with any battery building project, not just with Vruzend kits.
https://vruzend.com/product/vruzend_basic_kit/

Soldering isn't hard to learn but if you overheat your cells while building the pack you can degrade or ruin a cell in the process.

RC lipo batteries are mostly plug and play, but you need to know how to properly handle and charge them. Done right RC lipo is an inexpensive high drain battery that will perform well, but mis-handled it can burn your house down.....Literally.
 
Yeah I'm a little afraid of lipos. I'm willing to build a small banker for charging, if I finally choose them.
 
vagosofron said:
Yeah I'm a little afraid of lipos. I'm willing to build a small banker for charging, if I finally choose them.


The newset vruzend kit is almost ready to ship. I used Loctite green penetrating on my V1. All good.
 
tomjasz said:
vagosofron said:
Yeah I'm a little afraid of lipos. I'm willing to build a small banker for charging, if I finally choose them.


The newset vruzend kit is almost ready to ship. I used Loctite green penetrating on my V1. All good.
That's good news. Finally an alternative to welding/soldering.
 
Believe me, you will be using the motor on the way home. :mrgreen: You will come to enjoy riding faster.

Since its a 10 mile trip, that is a bit longer than I would recommend for using lead. If your ride was only 4 or 5 miles round trip, lead would be an option.

But a very heavy, cumbersome one. Lead is still ok enough for trikes that carry big weight better, and only go a few miles from home. otherwise, lithium is soooo much better.
 
dogman dan said:
Believe me, you will be using the motor on the way home. :mrgreen: You will come to enjoy riding faster.

Since its a 10 mile trip, that is a bit longer than I would recommend for using lead. If your ride was only 4 or 5 miles round trip, lead would be an option.

But a very heavy, cumbersome one. Lead is still ok enough for trikes that carry big weight better, and only go a few miles from home. otherwise, lithium is soooo much better.
The 5 miles on the way back are downhill, but i get what you're saying. I may try some lead acid at first ( i can find alot of those for free) and then invest on a lithium pack.
 
A home made Battery Bunker is always a good idea, no matter which type of Lithium battery you will be using.

It is easy to make a battery bunker using paving bricks and concrete retaining wall blocks.
https://www.homedepot.com/p/Valestone-Hardscapes-Domino-11-75-in-x-11-75-in-x-2-25-in-Victorian-Blend-Beige-Gray-Concrete-Paver-12050138/203659627

https://www.homedepot.com/p/RockWall-Large-6-in-x-17-5-in-x-7-in-Marine-Concrete-Retaining-Wall-Block-79890/204668216

Large Paving bricks on the bottom and top , and concrete blocks on the sides and if using hobby lipo's you can put each pack inside the two holes in each concrete block.
 
Question, is this type of battery efficient as the li-ion ones?
The battery is Li-Mn 36v 10Ah and comes in this casing. The weight is in kg.
Should i bother or pass?
 

Attachments

  • 12045720_2_b.jpg
    12045720_2_b.jpg
    66.4 KB · Views: 2,094
vagosofron said:
Question, is this type of battery efficient as the li-ion ones?
The battery is Li-Mn 36v 10Ah and comes in this casing. The weight is in kg.
Should i bother or pass?
Depends on the source! Has anyone else used them?
 
Ah, from a local shop here in Greece that closed and has 5 pieces left. They're chinece I'm sure, but in a really good price.
 
Nothing wrong with Li-Mn as a chemistry for the batteries. Maybe not the most energy dense, but certainly appropriate for an e-bike.
http://batteryuniversity.com/learn/article/types_of_lithium_ion

It probably comes down to the actual price and how much risk you want to take. I'd be inclined to take a volt meter to any battery I'd be buying and test it to make sure it has been stored properly. And if they are trying to get rid of five of these, Maybe they'll take a lowball offer just to get rid of one or two...
 
Back
Top