LiFeP04 Charging Question

[geem]

I also think that over the last year a lot of the initial stuff like which buss bars to use, compression or not, top and bottom balancing is getting clearer and many of these appear not as important as initially suggested.

8n summary, compression is now not a necessity but for all practical, purposes, you still need to do it to restrain the cells so they can be secured in a boat.
Top balancing is not an issue if you use grade A cells and a bms with an active balancer.
Busbars are easily made from copper bar. I just drilled mine and tapped to M8. There is no need to buy an expensive Victron Lynx system.
Cost of cells has dropped about 40% in 12 months.. NH00 fuses, one per battery, provide a good economic solution to fusing.

 

[Refueler]

I don't think cheap batteries will likely cause fires. They still have a bms that should shutdown the battery if it goes outside acceptable parameters. I think the battery failure rate is likely to increase as poorly matched cells cause more and more battery shutdowns.
Fires in lifepo4 chemistry batteries seem pretty impossible to start. It may be possible with a faulty charger running full amps and a BMS that has failed closed circuit but from those that know about bms electronics, I understand that that scenario is very unlikely.

Regardless of size of battery ... whether its a model pack of 1000mAh or a marine battery of 100A/hr .... the same applies ...

LiFe / LiFePo4 were developed as a safer alternative to the LiPo and a few other chemistry formats. For the small units - BMS is based usually in the charger itself ... but with larger packs where such as a bot / RV - then BMS is usually built into the battery case. The trade off though is the reduced output rates / greater weight per A/hr of LiFe vs LiPo. Example of LiPo output ... my Speed Record model 222kph was achieved with a 4500kv motor with a 1500mAhr 3S LiPo - the measured output was ~1KW .... I'll leave you to calculate the amps !! Needless to say - the batterys only survived 1 flight .... LiFe / LiFePo4 can never approach that figure in so small pack.

Lithium fires .... extremely rare with LiFe / LiCo etc. but not unknown with LiPo. The chemistries are sufficiently different to allow Thermal Runaway with LiPo - but not with LiFe unless subjected to extreme circumstances.

Most incidents with Lithium are connected to charge regimes or being overcharged. You could have incident if you were abale to discharge at a seriously high rate - but then cables etc would most likely fail before that.

I'll let y'all get back to marine based thread !!