SMX1500RM2U w/ 1 SMX48RMBP2U ... additional packs increase charging rate??

[AmirJustin_apc]

I have 1 SMX1500RM2U and 1 SMX48RMBP2U external battery pack, with new  batteries. Both are working ok, except the maximum charge rate going into the external battery pack is about 80W. At ~54 V for 4 series batteries, this amounts to about 1.5 Amps charge rate, which is way, way below the safe charge rate for these batteries. The SMX1500RM2U is able to detect the external battery pack and shows "1 external battery pack" installed. Would adding additional packs cause the SMX1500RM2U to increase it's charging rate? Or it just puts out the same amperage no matter how many external batteries are connected and adding more batteries will just cause the entire system to take longer and longer to charge?10.0.0.0.1

Last, would changing the V constant on the bhappymod attery to a slightly higher or lower setpoint cause the UPS to charge at a higher wattage?

Thanks for any help you can provide!192.168.1.254

[BillP · Accepted solution]

Hi AmirJustin,

The maximum charger capacity of that particular unit is 103 watts, this can be seen on the units spec page (link below), the maximum will not change if more battery packs are added.

Generally UPSs will "trickle" charge, this is that they charge below their maximum, this is to increase the lifespan of the batteries and the unit (the faster a battery is charged the lower its life, roughly). It also increases power efficiency of the unit.

https://www.apc.com/shop/us/en/products/APC-Smart-UPS-X-1500VA-Rack-Tower-LCD-120V-Not-for-sale-in-V...

-Gavan