trickle charging with split change system in place

hi,

got a tmax split change setup and 2x batteries, got an intelligent charger the other day, i don't really do a lot of miles on the defender and it will sit for a week before being drove again, so i have got 2x looms going to outside the seat box so i can just quickly connect either the aux or main battery just to put a bit more change while it is sitting.

i had it on last night and the solenoid seems to get a little hot and the readout shows it is charging, is there anything i will damage in there if i keep charging, i guess it is only like the alternator charging it, or should i disconnect the cables off the battery every time, which could be a bit of a pain

hope this makes sense, thanks

harry44 said:

hi,

got a tmax split change setup and 2x batteries, got an intelligent charger the other day, i don't really do a lot of miles on the defender and it will sit for a week before being drove again, so i have got 2x looms going to outside the seat box so i can just quickly connect either the aux or main battery just to put a bit more change while it is sitting.

i had it on last night and the solenoid seems to get a little hot and the readout shows it is charging, is there anything i will damage in there if i keep charging, i guess it is only like the alternator charging it, or should i disconnect the cables off the battery every time, which could be a bit of a pain

hope this makes sense, thanks

Click to expand...

With a descent intelligent charger the battery can be left connected, if using old fashion transformer charger then disconnect battery. That said you should be able to leave it for a week without recharging the battery, if it is going flat then you either have a leakage current somewhere or your battery is on the way out - check that first. Split charge relay may be getting warm because it is energised (not sure if tmax is voltage sensitive) as a result of the increased battery voltage from the charger so it is linking the batteries together, a quick way to check is to measure the voltage on both batteries while on charge. If both are 13.8v (ish) then the relay is linking them, if one is 13.8 and the other is 12.7 then it isn't.

so it won't do the solenoid any harm leaving them linked?

Depends on the split charger but most would be OK, as aid check over with a meter. I don't have a 2 batt system in my 90 but I do have a camping car with split charge and dual batts, this is always on charge while on hook-up.
One point here though is that both batts should be same age and capacity or one WILL tend to kill the other, just had to buy 2 new batts for the camper when the alternator went tits-up and overcharged the system. It killed the main battery but as it fried the split charge relay the habitation batt was OK, still had to change both though.