C-185

[8ntruck 6,358]

@Battaro - any update on this project?  It is an interesting one.

[DennisThornton 4,769]

On 1/19/2020 at 6:58 AM, Tractorhead said:

No Bad idea, but few Words about LiFePo Technic...

I don‘t know your Skills on LiFePo, but i see in the past a few Horrible Installations they be lucky nothing happens until now.

 

I‘m working since several years with light and stronger LiFePo and LiFePoY Batteries and Battery banks in RV‘s

and have more as 20 years own experiences with different Li Po and Li Ion and LiFePo Batteries in Modelling Aircraft and Dronez and different Powersystems.

I build from 90Ah single up to 3800Ah Battery Banks in serial or in parallel and both, this is my knowledge I can spent,

But there are several half truths in the knowledge of some.

 

first of all LiFePo‘s they had a potential for a so called „Thermal runout“ and cannot be extinguished.

They will allway’s burned down controlled, that shall be known, if you charging it in the House or in a Barn.

A few Safety rules therefore shall be urgently recommended.

 

 

If you like to use it in Winter for Snowplow Action i.eg.

You should know the LiFePo batteries needs to be prewarmed above -5degC if it should Charged.

A LiFePo Charger with Temp Sensors is urgently recommended.

First of all a Pole fuse on each battery plus Terminal that restricts to max. CCA

is not only a good idea, it‘s urgently required.

 

LiFePo‘s are fantastic Powerstorage no doubt about, but they need a bit more care taken otherwise selfignition of the Cells can be happen, even while Charging. A LiFePo needs urgently a BMS.

The new Generation has mostly a BMS (Battery Management System) internal in the Battery integrated, that protects the Battery for Safety use.

But liFePo‘s react a bit like a Diva to Overcharge and Overdrop of Current.

( means the Current shall never exceed the max. CCA the battery can deliver.)

When LiFePo‘s are Empty, the shutoff without any Warning handled by BMS. (A thing you should know)

 

 

There are some Battery manufacturer, they offered Charging below -10deg without any problems from their Salesmen,

but i ain‘t agreed after some Tests we did ourself. Even in the Leaflets it‘s mostly very small printed „no Charging below -5 deg.“

Some of the new Battery‘s has their own pre warming capability, so the recharge in colder Temps is possible but will need a bit longer Time. If LiFePo are in their Working condition, they consumpt all Current up to their Specification without troubles.

 

Also LiFePo‘s like the Running in between, means not permanent fully charged or discharged.

This is their best working condition. As more they used, as better will be their Performance.

a 110Ah LiFePo give you close about double use time instead of Gel or Lead Acid.

 

 

Therefore i assume you planing a complete change if you plan to use LiFePo‘s.

 

Main Advantage was

light weight, more Ah/weight, huge Ah in compare to Gel or Lead Acid,

quick Charging capability, no sulfatation, huge Discharge Capabilities,

depending on Battery manufacturer a external safety BMS is sometimes required.

few batteries have unusable different sizes. Can work in different Angles ( not all Batts)

 

Main Disadvantage was

special Charging Equipment is needed, can not be Charged below -5degC except few Manufacturer,

Cost, 

I just bought several Lithium Ion 18650s and I almost bought some big LiFePo cells but thought I should read up some more about them THEN I thought there's probably someone on this forum that works with them!  I was right!

[Tractorhead 8,576]

As long as you try to use them 18650 as single Battery , a good LifePo charger wiil be useful to recharge it.

 

If you plan it to bring them onto a Batterypack together - in series or in paraleel or even Both,

there must urgently a Balancer integrated to balancing the Cell‘s to each other.

 

The next requirement is a BMS. That protects from undervoltage ( deep discharge) to over Voltage (overcharge a cell)

and even on thermal protection.

Some maufacturer delivers Mainboards, where all this features are integrated, but if the also act as BMS they be mostly not cheap.

but prices on this kind of electronics drops fast.

 

A Lipo or LiFePo are very interesting Powersources, they can store a giant energy density.

But they don‘t like to be stressed too much.

LiFePo‘s are much safer than LiPo‘s about case of burning, but they don‘t be immortal.