# Charging while under load?



## blackresin (Apr 19, 2012)

Hi am new to the forum and have thought about ev’s for a couple of weeks, I have done some research and had a few ideas but could do with some help from the vast array of knowledge here to help me with some questions so forgive me if I ask a relatively simple question as I am a mech of the aircraft variety so have a rudimentary understanding of the Lecky trades or white mans magic as we call it were I work  I have quite a few questions but one that’s been bugging me for a while that I can’t seem to find any info about at present is as follows. So to the question:


If I was able to produce a charging voltage while a battery pack was under load is it possible to apply said voltage to keep to battery pack toped up with charge?(That said it would not be enough to run the load as the battery would be doing).
I know there is regenerative charging / braking that can be applied when the load is removed i.e. when costing or braking but if there was a continuous charge there is it even possible to keep said battery pack charged while under load or is that not even possible would you need two separate packs one under load while the other is under charge then swapped around?
How detrimental to the battery is it to have a battery continually toped up?
I know that in a similar way a laptop battery that is continually toped up after a short space of time becomes for a better word useless due to the inherent memory effort .I know there are batteries out there with no memory effect as they state but would this change if under continual top up?
Thanks for your time and sorry about any spelling or grammar mistakes


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## DIYguy (Sep 18, 2008)

Its no problem to do what you suggest. If your charge is less than your draw, your battery will supply the net difference. 
If you're referring to Lithium, there is no memory effect. This is how your 12 volt charge system works in your ICE car.


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## blackresin (Apr 19, 2012)

Thanks for the reply


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## Zak650 (Sep 20, 2008)

Hi,

I'm doing some bench testing on my system before it goes in my car and a strange thing is occuring. The battery pack is just 4 60ah lead acid cells I have setup for emergency power during outages. The charger for this pack is a small Soneil, it's been fine for this job for years. The drive system is a pmac motor used in motorcycles driven by a Sevcon Gen4 controller. Everything works great as long as I slow the motor down gradually and not let it produce too much regen. If I slow down rapidly the charger which is connected the whole time stops charging probably due to something that happens when the voltage climbs during motor slowdown. I have to physically disconnect the charger to get it to start charging again. These are just observations I do not profess to know why. 

A question I have is can you put a diode or scr in line with the charger to protect it or in doing so would it make the charger stop functioning for lack of feedback?


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## blackresin (Apr 19, 2012)

I am not experienced in all this but if the voltage rises more than what can be accepted by the batteries will this not back up the system for use of a better explanation, then when the voltage reaches the charger itself which will most likely have a safety feature attached to isolate it when in danger of overheating or destruction depending on how sophisticated it is will isolate its self from system. To reset this you may have to disconnect it from the system? By putting a diode in the circuit you will stop any back voltage/current reaching the charger itself I think I could be totally wrong because I am a mech I am going on what would happen if the system was hydraulic lol. But remember if using a diode use one that is scaled for the job.
Sorry if my answer didn’t make sense or is wrong: - )


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