Replacing UPS Batteries with Marine/RV Batteries

[KD6ICZ]

Great thread!

I'm about to do this with my Minute Man PRO1000RT UPS. It's just over a year old but one of the two 9 Ah SLA's swelled up and are dead. I'm not surprised with the level of heat that was inside the steel box. So going external will let the batteries stay much cooler.

I have been eyeing the 35 Ah Duracell AGM's that Batteries Plus sell. However with coupons the 35 Ah's at Harbor Freight look appealing as well. For sure a fuse will be added. I will most likely go with a 40A fuse since any fuse will blow in a short circuit situation.

Another battery caught my eye a Batteries Plus. It's also a Duracell but it is speciffically made for UPS applications. Here is a link:

https://www.batteriesplus.com/battery/sla-sealed-lead-acid/duracell-ultra/12/durhr12=100

Here is what the description says:

• 92.8 Watts per cell
• Best suited for float or emergency backup applications
• 10 year design life - 36 month warranty
• Thinner & more plates than general purpose; plate structure delivers power quickly
• Flame retardant
• Duracell Ultra High Rate AGM battery 12V 92.8WPC

I was hoping some of you that are more in the know could tell me if thiss sounds like something that would be worth a few extra dollars and a bit less capacity?

 

[anorlunda]

They sure whack you on price for those sealed AGM models. Batteries plus price for the 27 AH AGM battery you linked is $99, their price for a $75 AH flooded deep discharge battery is $88. That is nearly 3:1 ratio in $/AH.

If you need the sealed battery for safety, go ahead. But if you can put a flooded battery in a battery box someplace with ventilation, it is a much better deal.

 

[KD6ICZ]

They sure whack you on price for those sealed AGM models. Batteries plus price for the 27 AH AGM battery you linked is $99, their price for a $75 AH flooded deep discharge battery is $88. That is nearly 3:1 ratio in $/AH.

If you need the sealed battery for safety, go ahead. But if you can put a flooded battery in a battery box someplace with ventilation, it is a much better deal.

Oh believe me! If I could I would! I'm in the telecom industry and would love to have flooded cells that I could maintain! The wireless company I work for has some flooded cells that are 33 years old and still going strong! Unfortunately, there is an open pilot light about 2 feet away. So AGM's are a must!

The link I provided says these are designed for the constant trickle charge and come with a 3 year warranty. If they are really better suited then it might be worth the extra money.

 

[dlgoff]

... But if you can put a flooded battery in a battery box someplace with ventilation, it is a much better deal.

Not only that, but with a good documented maintenance procedure, you can make them last longer and have proof of proper care; should one fail.

 

[dlgoff]

... would love to have flooded cells that I could maintain!

You posted too fast.

 

[rbelli1]

I usually get about 3 years of standby out of the cheap ones. I just bought good ones so in a few years I will know if they are better. The original ones lasted over 10 years.

BoB

 

[KD6ICZ]

I ended up going with the 35Ah batteries at Harbor Freight Tools. With the 20% off coupon they were $60 each. They look as good as any other Chinese made battery. At least I have a core to turn in next time I need to replace them.