Thread: Has my Traxide BMS let me down?

Tim from Traxide usually monitors these threads. If he doesn’t reply in a day or so maybe send Traxide an email

Originally Posted by Tin Lizzy

... I think I left the USI-160 BMS in ignition mode, but can’t be sure.

If that is the case I believe it should have isolated your cranking from your aux battery very much earlier than if you had left it in the recommended 'shared' mode.

Your aux battery was probably being propped up by your cranking battery (hence self discharged when isolated for such a long time) and your cranking battery is always running some systems even while parked up for 14 weeks. Result - 2 flat batteries, nothing to do with the BMS I think.

Hi Tim and sorry mate, but you can not leave any lead acid battery for 14 weeks without some sort of maintenance charging while you are away.

Even 4 weeks weeks would be the limit and that’s providing the batteries are fully charged in the first place.

If this type of situation occurs again, either fit a low current trickle charger or a small solar panel.

Or a day or so before you leave, fully charge both batteries and then remove the negative lead off both batteries. While this is not ideal, it will leave the batteries in a better state for when you get home.

Originally Posted by drivesafe

Hi Tim and sorry mate but you can not leave any lead acid battery for 14 weeks without some sort of maintenance charging while you are away.

Even 4 weeks weeks would be the limit and that’s providing the batteries are fully charged in the first place.

If this type of situation occurs again, either fit a low current trickle charger or a small solar panel.

Or a day or so before you leave, fully charge both batteries and then remove the negative lead off both batteries. While this is not idea, it will leave the batteries in a better state when you get home.

Only viable if vehicle is in a secure facility.
Otherwise you cannot lock the vehicle.


14 weeks would definitely have the car flatten the main battery - maximum I’ve seen before it won’t start is around 2.5 weeks.

I have a small solar panel on my roof to maintain the vehicle when parked up for this exact reason.

I have Anderson plugs at both front and rear of our l320. With the traxide system it is easy to connect battery charger to either and keep batteries fully charged. I use these to plug into my caravan as well to keep all fully charged when camping with caravan solar and charger.

Originally Posted by Tombie

Only viable if vehicle is in a secure facility.
Otherwise you cannot lock the vehicle.

Before leaving : Bonnet up, lock vehicle, disconnect battery, close bonnet.
On return : Key unlock passenger side door, bonnet up, reconnect battery, close bonnet.

Originally Posted by BradC

Before leaving : Bonnet up, lock vehicle, disconnect battery, close bonnet.
On return : Key unlock passenger side door, bonnet up, reconnect battery, close bonnet.

Don’t some bridge out bonnet switch,problem fixed for good?

IMHO not really needed anyway.

Originally Posted by scarry

Don’t some bridge out bonnet switch,problem fixed for good?

IMHO not really needed anyway.

Regardless, it's irrelevant in this scenario. All that happens is when you lock with the bonnet up the horn honks once. It still locks all the doors.
Disconnect the battery and close the bonnet. Job done.

Before you do that it'd be a good idea to check that your passenger side key lock actually works. Most seem to lie unused until they are needed by which time they're frozen solid.

Another option is to power the car up through the white 12S socket and unlock with the remote, but without a battery connected you'll need a solid power supply >= 10A to get the thing to boot. Last time I tried to charge a flat battery with a 5A power supply, the boot up current of all the ECUs was such it kept pulling the voltage down causing a boot loop. Had to disconnect the battery to get a float onto it.