Which battery to choose, Li-Ion or LifePo4?

[imorton]

Hi Guys, there's a wealth of info here, and maybe some of you can enlighten me? I am trying to decide between three BMSbattery batteries. The 48v battery pack with either 10Ah or 15Ah Li-Ion, or the 9Ah LifePo4.

I have a Gio scooter like in my profile/avatar, and it is 350w continuous and 500w peak at 48volts. The controller is 17amps, and I might modify it to go up to 25 amps eventually.

I ride in generally flat areas with slight hills, and my distance needs are anywhere between 10-20 km's and the scooter tops out at 32kmh

BMS Battery has a few interesting batteries that I'm try to decide between and I would love to know the PRO's and CON's of each.

BATTERY #A = 48v 10Ah Li-Ion with 3a charger for $218 plus shipping = $304 total http://www.bmsbattery.com/48v/166-48v-10ah-lithium-ion-electric-bicycle-battery-pack.html

BATTERY #B = 48v 9A LifePo4 38120 Headway cell, no charger, for $224 plus charger and shipping = $368 total http://www.bmsbattery.com/packs/559-48v-10ah-38120-lifepo4-battery-16-cells-ebike-battery-pack.html

BATTERY #C = 48v 15Ah Li-Ion with 4a charger for $299 plus shipping = $382 total http://www.bmsbattery.com/48v/248-48v-10ah-lithium-ion-electric-bicycle-battery-pack.html




The questions that I have are?

1) Cycle life of each versus Calendar life, and Performance longevity?

2) The realistic amperage or C rating of each style battery pack with a 17-25 amp controller. Is the Li-Ion good for me?

3) The max reasonable charging C rate for LifePo4 or Li-Ion (to keep good cycle life)

4) The battery repairability should a cell go bad. The Headway cells seems easy to repair/replace. What about the Li-Ion?

5) The "on the road" feasibility of being able to remove battery pack from scooter (put it in my discreet bag) and use the interior 120v AC plug of a restaurant or coffee shop 120v AC plug while I eat/have a coffee

6) The size and weight difference between Li-Ion and the LifePo4 Headway pack.

7) The 9Ah LifePo4 Headway pack is strange, I didn't know that Headway made 9Ah cells?


Thanks a million for sharing your thoughts and information… IAN.

 

[dogman dan]

Theoretically the lifepo4 pack would last longer in cycles. And it appears that the headway pack can supply more amps than the others. But it will be much more bulky than the others. Even so, it may still be plenty small enough to carry in and charge.

If you do go with the LiNiCoMn, they you must get the larger 15 ah one. Why? so the bike will strain the battery less, particularly if you increase amps. This example seems to be lower discharge rate than the headways, so 15 ah is a good size. Since this is smaller, you can fit the 15 ah easy.

I'd be inclined to go with the headways myself, since I'd be capable of fixing the pack if a cell went bad, and the discharge rate of the cells seems better. Expected cycles is at least double for lifepo4 too. But more range from the 15 ah linicomn has appeal.

 

[drebikes]

Here are a few answers

1) Cycle life of each versus Calendar life, and Performance longevity?

LiFePo4 are known to excel in those metrics

2) The realistic amperage or C rating of each style battery pack with a 17-25 amp controller. Is the Li-Ion good for me?

For 25A you'd need between 1.5 and 2.5C depending on the battery pack Ah; I would prefer the 15Ah if only to have lower C-rating discharge; if your necessary is 20km at say an average 20km/h than you'd need the battery to hold about an hour, which is 1C average. Then for 17Amps max, maybe 12Amps average, you'd practically need the 15Ah battery just to cover the distance.

3) The max reasonable charging C rate for LifePo4 or Li-Ion (to keep good cycle life)

The conservatives would say 0.5C, but many packs can take more like 2-3C. It depends if you want to do that max repeatedly or only from time to time and also if you want to charge every last % or just a boost from say 30 to 60%. As long as you trickle-charge from time to time (0.3C or thereabouts) it should be fine.

4) The battery repairability should a cell go bad. The Headway cells seems easy to repair/replace. What about the Li-Ion?

Don't know

5) The "on the road" feasibility of being able to remove battery pack from scooter (put it in my discreet bag) and use the interior 120v AC plug of a restaurant or coffee shop 120v AC plug while I eat/have a coffee

I think it depends more on the bag size/type. Of course LiMn being smaller and lighter than Lifepo4 @same Ah would be easier to handle

6) The size and weight difference between Li-Ion and the LifePo4 Headway pack.

7) The 9Ah LifePo4 Headway pack is strange, I didn't know that Headway made 9Ah cells?

It can be 6 parallel of 1.5mAh for example

 

[imorton]

Theoretically the lifepo4 pack would last longer in cycles. And it appears that the headway pack can supply more amps than the others. But it will be much more bulky than the others. Even so, it may still be plenty small enough to carry in and charge.

If you do go with the LiNiCoMn, they you must get the larger 15 ah one. Why? so the bike will strain the battery less, particularly if you increase amps. This example seems to be lower discharge rate than the headways, so 15 ah is a good size. Since this is smaller, you can fit the 15 ah easy.

I'd be inclined to go with the headways myself, since I'd be capable of fixing the pack if a cell went bad, and the discharge rate of the cells seems better. Expected cycles is at least double for lifepo4 too. But more range from the 15 ah linicomn has appeal.

Dogman, thanks a million for your info and thoughts. I see that there is decisions, decisions, decisions…

The 15Ah LiNiCoMn is appealing, but I can't really repair that pack. The range looks better than the Headway cells, but the Headways are easily repaired/replaced.

Question regarding "opportunity charging" inside a coffee shop etc…?

1) Can I use my 48v 2amp SLA charger to trickle charge the Headways overnight, and buy either the 400w or 600w BMSbattery Alloy charger for faster bulk "opportunity" charging?

2) Unfortunately the BMSbattery website don't put the dimensions on the 400w http://www.bmsbattery.com/alloy-she...po4li-ionlead-acid-battery-ebike-charger.html or 600w http://www.bmsbattery.com/alloy-she...po4li-ionlead-acid-battery-ebike-charger.html chargers. Any ideas as to their sizes, or the 120v input current specs?

3) My current scooters 48v 12Ah SLA batteries provide me with @ 7Ah due to Peukerts so I tend to be very gentle on amperage demand (ride slower). So the 48v 9Ah Headways would be very similar in range, especially considering that I would tend to ride wide-open throttle/full speed with the Headways. But with the Headways, it's likely easier to remove and opportunity bulk charge in a coffee shop when the need arises?

Thanks again for helping me with your insights.. IAN

 

[imorton]

DREBIKES, thanks very much for helping me with your answers.

You make some good points about the discharging C rate and even though the LiCoNiMn 10Ah pack pricing is appealing, I may very well be stressing that pack into a very short cycle life.

For a short cycle life, I may as well get inexpensive SLAs, so I guess the Headways are starting to look like a better longterm value. Especially since my long distance needs are sporadic and I now realize that taking the batteries out of the scooter to opportunity charge is much more feasible and easier than trying to find an exterior 120v plug.

It would be nice to buy a 30Ah pack and almost never have to think about running out of power, but that would cost more than the scooter actually cost

I guess we all have to analyze or Needs and Wants..

Thanks again, IAN

 

[Suspect]

One of two chargers I've purchased from BMS were garbage out of the box.
That could be a cost factor worth considering.

 

[999zip999]

Not the biggest fan of bmsbattery. I vote for the headway pack though 9ah is small with headway you could get 9ah more later for range and is easier on the pack. I would like my headway pack with an extra set of sense wires to plug a cellog in to check balance and to access if one cell is high or low.

 

[imorton]

One of two chargers I've purchased from BMS were garbage out of the box.
That could be a cost factor worth considering.

I guess we all have to factor this when we purchase from China

 

[imorton]

Not the biggest fan of bmsbattery. I vote for the headway pack though 9ah is small with headway you could get 9ah more later for range and is easier on the pack.

Good point about potentially adding a second pack. What I don't understand is that there is no specs on the 9Ah Headway cells, I see that they have 8Ah and 10Ah cells, so are the rejects or B grade cells?

IAN…

 

[dnmun]

One of two chargers I've purchased from BMS were garbage out of the box.
That could be a cost factor worth considering.

what was wrong with your charger? did you post up on the BMS battery charger thread? we have been able to get them to replace chargers after we showed them how they were dead from the start.

 

[alsmith]

One of two chargers I've purchased from BMS were garbage out of the box.
That could be a cost factor worth considering.

what was wrong with your charger? did you post up on the BMS battery charger thread? we have been able to get them to replace chargers after we showed them how they were dead from the start.

+1

I ordered two because the possibility of problems are well documented here. Good move because only one worked. That meant I could run while 'discussing' and getting a replacement, and repair the non-working one with the help of the info in the threads on es.