Lifepo4 Cells

[Garry Hallam]

Has anybody had any experience with Tipsun lifepo4 Chinese cells. I ordered some screw terminal 32700 6000mah to experiment with ? I bought with the intention of being able to use them to build a leisure battery if they do not work out for bike batteries.

My main question is giving that they say Constant Voltage / Constant current charging. Is it possible to charge with a Lab power supply?

 

[saneagle]

Has anybody had any experience with Tipsun lifepo4 Chinese cells. I ordered some screw terminal 32700 6000mah to experiment with ? I bought with the intention of being able to use them to build a leisure battery if they do not work out for bike batteries.

My main question is giving that they say Constant Voltage / Constant current charging. Is it possible to charge with a Lab power supply?

You don't make it clear what you mean by "charge". Do you mean individually or as a pack with or without a BMS? Whatever it is, you can charge them with a lab power supply for experimental and setting up purposes, but if you want to use them for a house or ebike battery, you should fit a BMS and a proper charger. The lab power supply works more or less the same as a normal charger, but it's too easy to knock a knob to deviate from the setting. Normal chargers are very cheap anyway.

 

[Garry Hallam]

Yes I meant for setting up. I will of course use a dedicated lifepo4 bms as. In the case of a 36v pack It is possible to buy a 13s bms which brings the fully charged 3.65v cells to 43.8v but I have not seen a 43.8v charger for this?

 

[saneagle]

Yes I meant for setting up. I will of course use a dedicated lifepo4 bms as. In the case of a 36v pack It is possible to buy a 13s bms which brings the fully charged 3.65v cells to 43.8v but I have not seen a 43.8v charger for this?

Yes, I have a load of 36v LiFePO4 chargers. They're 43.8v for 12S, not 13S.

LiitoKala 12S-43.8V2A LiFePO4 battery Charger 36V2A LiFePO4 Charger Used for 12S 36V Electric bike battery LFP

Smarter Shopping, Better Living! Aliexpress.com

vi.aliexpress.com

It's cheaper to buy two to get the free shipping, but if you search Aliexpress, you should be able to find one for around £10 with free shipping.

 

[Garry Hallam]

Yes, I have a load of 36v LiFePO4 chargers. They're 43.8v for 12S, not 13S.

LiitoKala 12S-43.8V2A LiFePO4 battery Charger 36V2A LiFePO4 Charger Used for 12S 36V Electric bike battery LFP

Smarter Shopping, Better Living! Aliexpress.com

vi.aliexpress.com

It's cheaper to buy two to get the free shipping, but if you search Aliexpress, you should be able to find one for around £10 with free shipping.

Thanks. I found and ordered one for £8

 

[Ghost1951]

Thanks. I found and ordered one for £8

I hope you will keep us posted on your experiments Gary.

I have had a thought or two about this kind of LifePo4 e-bike battery experiment for when my current batteries turn their toes up. I think screw terminals and bus bars would be easy to put together, so it is certainly doable from the fabrication point of view. The question is - how will they perform, and who is selling good LifePo4 cells.

It will be interesting to see how you get on with the weight and capacity disadvantages vis a vis the more usual chemistry for bike batteries. Hope it does well for you, but either way, let us know.

Cheers.

 

[saneagle]

I hope you will keep us posted on your experiments Gary.

I have had a thought or two about this kind of LifePo4 e-bike battery experiment for when my current batteries turn their toes up. I think screw terminals and bus bars would be easy to put together, so it is certainly doable from the fabrication point of view. The question is - how will they perform, and who is selling good LifePo4 cells.

It will be interesting to see how you get on with the weight and capacity disadvantages vis a vis the more usual chemistry for bike batteries. Hope it does well for you, but either way, let us know.

Cheers.

You can get 18650 size LiFePO4 cells that you weld just like a normal battery. The only difference is that you need more cells to get the same capacity, which results in more weight. The big cells with screw tops require even more space than the 18650s, so you end up with a bigger and heavier battery that might last longer. Although LiFePO4 is supposed to last longer, you can still get problems with individual cells, especially the pouch and prismatic cells.t least with the big cyclindrical ones, you can just unscrew and replace any faulty ones.

Around 2012, I had a 10Ah 36v battery with the big screw top cyclindrical Headway cells. I think I was running with 22A, but it kept cutting out when I ran max power for too long. It was a rack battery sold by BMSBattery. I'm not sure if it was the BMS or cells causing the problem. I never opened it to check. I think I sold it on a working ebike that I built for someone.

 

[Ghost1951]

You can get 18650 size LiFePO4 cells that you weld just like a normal battery. The only difference is that you need more cells to get the same capacity, which results in more weight. The big cells with screw tops require even more space than the 18650s, so you end up with a bigger and heavier battery that might last longer. Although LiFePO4 is supposed to last longer, you can still get problems with individual cells, especially the pouch and prismatic cells.t least with the big cyclindrical ones, you can just unscrew and replace any faulty ones.

Around 2012, I had a 10Ah 36v battery with the big screw top cyclindrical Headway cells. I think I was running with 22A, but it kept cutting out when I ran max power for too long. It was a rack battery sold by BMSBattery. I'm not sure if it was the BMS or cells causing the problem. I never opened it to check. I think I sold it on a working ebike that I built for someone.

Thanks for the account of your experience.

Yes - you can get some pretty big LifePo4 cells with screw fixings. I kind of fancied the idea of being able to remove a bad cell. I have a weak cell group on the battery on one of my bikes - the one with the BBS01. I can easily top up the weak group when they go badly out of balance because I brought leads from the group out to fused insulated contacts on the outside, so when needed I can just put that group on a slow controlled charge and bring them back to balance, but if it had been possible, I would have removed the bad cell - it is likely to be just one in the group which drains down the rest.

I am not prepared to weld cells and mess about like that, but the meccano approach of screwing the bus bars on, is a good way for me. It wouldn't suit everybody - I know that - and neither would the lower energy density of LifePo4, but I'm happy with a bigger heavier battery and I don't need massive output. The BBS01 bike has a max draw of 15 or 16 amps and as you know the wee Argos one has a max of 8 amps - lol - if I can live with that, and I actually like riding it, I can live with LifePo4, I think.

The fire safety angle suits me too.

 

[Garry Hallam]

I just feel

Thanks for the account of your experience.

Yes - you can get some pretty big LifePo4 cells with screw fixings. I kind of fancied the idea of being able to remove a bad cell. I have a weak cell group on the battery on one of my bikes - the one with the BBS01. I can easily top up the weak group when they go badly out of balance because I brought leads from the group out to fused insulated contacts on the outside, so when needed I can just put that group on a slow controlled charge and bring them back to balance, but if it had been possible, I would have removed the bad cell - it is likely to be just one in the group which drains down the rest.

I am not prepared to weld cells and mess about like that, but the meccano approach of screwing the bus bars on, is a good way for me. It wouldn't suit everybody - I know that - and neither would the lower energy density of LifePo4, but I'm happy with a bigger heavier battery and I don't need massive output. The BBS01 bike has a max draw of 15 or 16 amps and as you know the wee Argos one has a max of 8 amps - lol - if I can live with that, and I actually like riding it, I can live with LifePo4, I think.

The fire safety angle suits me too.

It is the lesser of two evils for me, for all of the same reasons you mention!

 

[saneagle]

Thanks for the account of your experience.

Yes - you can get some pretty big LifePo4 cells with screw fixings. I kind of fancied the idea of being able to remove a bad cell. I have a weak cell group on the battery on one of my bikes - the one with the BBS01. I can easily top up the weak group when they go badly out of balance because I brought leads from the group out to fused insulated contacts on the outside, so when needed I can just put that group on a slow controlled charge and bring them back to balance, but if it had been possible, I would have removed the bad cell - it is likely to be just one in the group which drains down the rest.

I am not prepared to weld cells and mess about like that, but the meccano approach of screwing the bus bars on, is a good way for me. It wouldn't suit everybody - I know that - and neither would the lower energy density of LifePo4, but I'm happy with a bigger heavier battery and I don't need massive output. The BBS01 bike has a max draw of 15 or 16 amps and as you know the wee Argos one has a max of 8 amps - lol - if I can live with that, and I actually like riding it, I can live with LifePo4, I think.

The fire safety angle suits me too.

I think it's a false economy to replace cells on a well-used battery. I might try it on a new one, when you can reasonably expect the good cells to be good and stay good, but on an older battery, one cell-group will always fail first, then the others follow more likely sooner than later.