When I start up my engine, my SmartBank connects, then disconnects a few times before settling down. What causes it and will it cause any problems ?

First let's explain what happens with the SmartBank.....

If either battery voltage reaches the "connect voltage", SmartBank will then parallel both batteries to enable both to be charged. This is not an instant decision. There is some severe filtering of the battery voltages and a short delay before this happens. Further, the delays are dynamic in that they vary depending upon the rate of change of battery voltage. This is to prevent SmartBank responding to false triggers such as load dumps and voltage spikes. Likewise when the battery voltage falls below the disconnect voltage the batteries will be separated. Again there is a delay and some filtering.

If you find that SmartBank connects then almost immediately disconnects you probably have one of the following problems......

Too small a charger for the battery bank. Assume you have a 100Ah battery with a 10 amp charger connected to it and the other battery bank is a deeply discharged 400Ah bank. The 10 amp charger will happily bring the 100Ah battery up to the "connect voltage". There then follows a short delay until SmartBank parallels in the other (400Ah) battery bank but when this happens the 10 amp charger is simply far too small to bring the deeply discharged battery up above the "disconnect voltage" before SmartBank senses the low voltage level and disconnects. A 10 amp charger on a total of 500Ahrs of batteries is akin to filling up a bath tub with a water pistol.

The solution in this case is obvious. Clearly the battery charger is nowhere near powerful enough to charge such a large battery bank. Increase the size of the charger !

A cure (technically a kludge!) may be found by connecting the charger to the largest of the battery banks.

Alternatively, as a temporary solution, you could adjust the "disconnect" voltage below the level at which the large battery bank is running to at least enable some charge to be put in before curing the real problem, ie that of the charger being insufficiently sized.

The "connect" and "disconnect" voltages are set too close. If you have recalibrated the unit from the factory settings then you may have adjusted the "disconnect" voltage too high. This results in the same cycling problem. The solution is simply to reset the voltage thresholds to those detailed in the owner's manual for your battery types.

Note that all SmartBanks shipped between 28th April 2003 and 30th November 2003 have a modified algorithm to help alleviate the problem caused by insufficiently sized chargers. If you own a unit shipped prior to this date then an update is available for which the SmartBank will need to be returned to SmartGauge Electronics. There is a small charge for this service.

Please note that this does not apply in the case of SmartBank Advanced used in conjunction with SmartGauge. No modification is required in this case because the problem cannot arise.

SmartBanks shipped after 1st December 2003 have yet another feature added to help with the problem of chargers being too small for the total battery bank size. This is a user adjustable time delay, immediately following "connect", whereby SmartBank simply will not and cannot disconnect the relay irrespective of what happens to the battery voltage. This delay is continuously adjustable from zero to 90 seconds. If the charge source cannot get the battery voltage above the disconnect voltage within 90 seconds then it quite simply will never, ever, charge that battery bank no matter how long it is left connected. It is simply FAR too small.

Again this does not apply in the case of SmartBank Advanced used in conjunction with SmartGauge. In this case the hold time is automatically adjusted by SmartGauge.

Of course the real solution is to ensure the charger is up to the job of recharging the whole battery bank !


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