Engine charging (1 Viewer)

[Kannon Fodda]

Believe it or not we would prefer the industry to do it correctly in the first place

To this day the vast majority of people think that the alternator charges the engine battery and then, when charged concentrates on the leisure battery and that this is somehow efficient. As opposed to a crap relay (in a fancy box or not) and a bit of wire about the thickness of a boot lace !

I'll admit to being naive when I bought my van, didn't know to make enquiries on the electrics, just thought they would do given the vehicle seemed to have a lot of kit as standard. Then started to use it and found the achilles heel of the fancy box and boot lace wire. It isn't something covered in the average review of motorhomes either.

 

[andy63]

The smart alternator regeneration would still need some battery space. As I understand it the alternator load is reduced when the power is needed for driving. However when slowing down or braking the alternator load is increased to produce more current and adds to the braking effect.

You are missing the point im trying to make..not all smart alternators employ regenerative braking..
Some simply charge the battery ..and then reduce the voltage so they unload..reducing the load on the engine over the period of the journey..in such cases I cant see the need for batteries not to be fully charged up to the capability of the alternator..
My transit has a smart alternator..but it doesn't employ regenerative braking...ie applying a higher load on the engine under braking...as far as i know ..
Andy

 

[ctc]

Am in right in thinking this 80% capacity limit on the battery is only applicable if you have systems like regenerative braking running in conjunction with smart alternators..
That is not always the case as smart alternators can be fitted and still beneficial without the other these other systems..
Andy

I was told (and it seems to work) that the alternator switches off at 80% cab battery capacity ignoring the leisure batteries, I have a USB socket with a voltage display plugged into the fag socket, I get 14.4v for a while then off then 13.2v for a short time (5 mins) then off. With the lights on 14.4v until the cab battery is 80% (12.5v on my MH display) then 13.2v continuous. Leisure batteries always nicely charged. My 90ah cab battery failed in France they fitted a 110ah (250 euros!) when I asked why they said 80% of 90ah was not enough for short runs??? Mercedes recommends 110ah with smart alternators.

^{_{Subscribers  do not see these advertisements}}

 

[Pausim]

You are missing the point im trying to make..not all smart alternators employ regenerative braking..
Some simply charge the battery ..and then reduce the voltage so they unload..reducing the load on the engine over the period of the journey..in such cases I cant see the need for batteries not to be fully charged up to the capability of the alternator..
My transit has a smart alternator..but it doesn't employ regenerative braking...ie applying a higher load on the engine under braking...as far as i know ..
Andy

That suggests some alternators are smart and some are just a bit clever.