Charge spare SMX750/1500 batteries externally?

[Anonymous user]

I happen to have some NIB spare batteries for my SMX750's and 1500's. It occured to me that probably I should be charging them at least occasionally. I obviously don't want to swap them in and out of the UPS's. So I need an external charger for them. Can I buy a unit to do that? Worst case I suppose if it is possible, I could build one if shown how. Thank you.

[BillP]

Hi Douglas,

We do not sell any external battery chargers like you have described and do not support the use of 3rd party batts or building of such a charger.

Regards,

[Anonymous user]

These are not 3rd party batteries, and it is none of your business if I buy a commercial charger for your batteries. But since you were so rude, I will buy 3rd party batteries for my ASPC UPS's in the future. FY.

[BillP]

Douglas,

NIB is a 3rd party battery vendor, unless you meant "New In Box".

If you were offended by shortness of my direct answer, I apologize but it remains that we do not sell external chargers.

Regards,

[MarkC_apc]

I'm familiar with the SMX1500 in that it operates at nominal 48 volt DC - not sure about the 750 model (blue Andersen connector?).  Granite makes a 48 volt charger that I have used in the past to stage charge small 48 volt AGM battery systems - as well as maintenance only charge on a large 48V FLA battery bank.  Seems to work well in both situations.  It also claims de-sulfating capabilities, which may be "voodo magic" - don't really know.

Warning - be very careful when handling high voltage DC.  Also, I would not continuously charge AGMs with any external charger - (except the APC UPS unit charger of course).  Most are not designed with enough "smarts".

[Anonymous user]

Oh. I never heard of the NIB company, and yes I meant New in the Box. The point was that I have a number of APC batteries as spares for my UPS's--that was a mistake because I was under the impression until recently that their life would not be shortened by waiting for use. If their lifespan is indeed shortening by sitting for a couple years without being charged, then I would like to charge them occasionally with an external charger. My alternative would be having an unused UPS solely for the purpose of swapping batteries in and out to keep them charged. I wonder if I have to have some load on that UPS. I think it would be useful for APC to publish an app note on this topic, describing what they recommend about having spare batteries or not, and if there are spare batteries, do their lives degrade by being out of use for as long as (say) a year or two until needed.

[BillP]

Douglas,

You may search for K-Base article FA156516 titled "Battery Discharge during Storage" in the below link for APC's recommended best practices:

http://www.apc.com/site/support/us/en/faq/

Regards,

[Terry_Kennedy_apc]

Technically what you have is NOS (New Old Stock) at this point. You can look at various battery manufacturer's web sites for their suggestions for storage and frequency of charge. For example, here is the sheet for the CSB1221W battery, which is commonly used in APC battery packs.

APC likely can't provide advice about chargers they aren't familiar with, possibly in conjunction with a brand of battery they don't use themselves. So I'd cut them a bit of slack for their answer.

If you search for "VRLA battery charger" you'll see a wide variety of styles and prices. Price is no indication of quality. Many of these units will end up boiling the batteries if you leave the charger connected full-time. For attended "topping up" operations, you can get away with just about anything. After Hurricane Sandy ran my UPS batteries down to nothing, I used a car battery charger to charge the batteries enough to get my UPSs to turn back on. Not recommended, but I knew the batteries all needed to be replaced anyway as they were run down to dead and left that way for 2 weeks while the power was out.

[Anonymous user]

Terry, thnak you for that very helpful message. I haven't searched much yet, the first place I went was Amazon, where I found this. Am I headed in the right direction?

[Anonymous user · Accepted solution]

If your have extra batteries you might be better off selling them on ebay so you don't have to play games with keeping them charged 

Or, use a battery tender like found in marine applications where the idea is to keep boat batteries charged for the occasional weekend use.