do EHU's charge your battery ??

[Bigpeetee]

Yes it's not very efficient charging leisure batteries direct off the alternator. But electrically it shouldn't know the difference between the leisure batteries and the starter battery as they are connected by a 100A cable on mine when charging. I just find the alternator is blunderbuss approach as it charges at constant voltage whereas you need a box of tricks to give sequences of contact voltage and constant current charging to build up the leisure battery charge to optimum levels. The starter battery doesn't matter as 80-90% charge is fine for starting, but with a leisure battery you want to maximise the charge to use that extra 10-20% capacity.

Sadly most MH don't have a good cable to charge as we do, so they generally get only about a 4A charge.

I use the alternator for bulk charging and the solar for topping up, but I try to reduce the power consumption first and I've got 280AH leisure batts. The solar regulator has 4 stage charging.

Last time I used EHU was about 2.5 yrs a go!! Sorry about 12 months a go to check it still worked!!!

 

[Firefox]

Another thing I find strange is that they recommend something like a 30A cable and 15A fuse for the split charging circuit. In this past year I have seen two 15A fuses blow on different self build charging circuits. If the leisure battery is quite flat I reckon the alternator can give more than a 15A surge when started up

I'd go for at least an 80A cable and 30A fuse, more if possible. This gives protection against the above scenario and also lowers the voltage drop across the link as well as cutting heat loss in the link wire making charging more efficient.

 

[james pond]

cheers everyone for the info even though most of it goes right over my head; firefox, cheers for the tips, will get a meter thingy and have a go, see what i can figure out; did look at the scooter charger, no mention of wattage, seems to say 1A/2A i think the writing is small and very faint. can however figure out 24V ; methinks this will make things even harder, never heard of a 24V charger before. as for connecting an inverter direct to a battery like you, the thought of it makes me go weak at the knees; visions of sparks, smoke and flames; and when the missus calms down the battery will be bu****ed too. if i were to get someone to do it though would 3 or 4 hours pootling round country lanes every day be enough to charge the scooter you think.

 

[Firefox]

Big inverters come with their own thick cables you just bolt straight on the battery terminals. 1000w at 12V is over 80 Amps, that's why they need to be thick!

Multimeter is definitely worth investing in because you can tell what state of charge your battery is in. Try to keep it above 12v which around 50% charge. 12.8 to 12.9 v is fully charged, and charging should around 14 to 14.5v. These are the main voltages to remember.

Some control panels have LEDs which give you the charge state, good medium or poor, or even just good and poor. These can be inaccurate though and they don't give the intermediate positions. You can use the multimeter to find out what light corresponds to what voltage which will give you a better idea.

 

[james pond]

thanks to oldish hippy and mandrake for the instruction manual link. had a read thru it, least i found out what the orange switch was ; the on/off ; yes i know, did warn you i was electrically challenged.
when i read thru the exchanges between other guys out there i go green with envy; 4 stage solar chargers, sequential voltage watsit, various ampage wires and fuses tripping off the tongue as easily as me wifey gossipping over the garden fence !!