Battery Back for Boiler

hotblast1357 · Post by **hotblast1357** » Tue. Jun. 16, 2015 1:38 pm

I'm thinking of a 12v battery back up with a pure sine wave inverter too power my one grundfos pump .75 amps, and my dump zone modine which draws 1.3 amps. Who has them set up and what do you think? This is for when the power goes out in the middle of the night or when I'm away at work, just to keep it from over heating.

nepacoal · Post by **nepacoal** » Tue. Jun. 16, 2015 4:46 pm

I use an APS750 from tripplite for my sf260. I primarily put it in to control any overheating during a power outage but it with two deep cycle batteries from tractor supply in parallel it will power my hand fired boiler for more than 24 hours (based on 10 minutes per hour of runtime). The pumps do whine a little when using the non-sine wave inverter but I rarely lose power so it gives me peace of mind in case of high temps during the occasional outage. I will be looking into sine wave units when my stoker is installed.

lsayre · Post by **lsayre** » Tue. Jun. 16, 2015 5:03 pm

hotblast1357 wrote:I'm thinking of a 12v battery back up with a pure sine wave inverter too power my one grundfos pump .75 amps, and my dump zone modine which draws 1.3 amps. Who has them set up and what do you think? This is for when the power goes out in the middle of the night or when I'm away at work, just to keep it from over heating.

Sounds like a job for a relay that will kick in when the grid power drops and flip your dump zone over to the inverter (and then flip you back to the grid when power is restored). That would be effectively an automatic transfer switch, and the legality of such a do it yourself device may be somewhat questionable.

hotblast1357 · Post by **hotblast1357** » Tue. Jun. 16, 2015 5:24 pm

What is questionable?

lsayre · Post by **lsayre** » Tue. Jun. 16, 2015 5:32 pm

hotblast1357 wrote:What is questionable?

A do it yourself auto transfer switch.

hotblast1357 · Post by **hotblast1357** » Tue. Jun. 16, 2015 5:49 pm

Why would u need a auto transfer switch? Isn't the inverter automatically picking up were the battery charger is dropping?

McGiever · Post by **McGiever** » Tue. Jun. 16, 2015 5:57 pm

hotblast1357 wrote:Why would u need a auto transfer switch? Isn't the inverter automatically picking up were the battery charger is dropping?

A UPS, Yes...a inverter, No.

You want a UPS...(uninteruptable power supply) to have a built-in transfer.

Inverter has no battery or charger.

hotblast1357 · Post by **hotblast1357** » Tue. Jun. 16, 2015 6:09 pm

I know they don't mcgiever, thanks though, I will need a automatic trickle charger a battery or two, and a pure sine wave inverter, and maybe a relay, I was just wondering if people were doing it successfully. Thanks nepacoal for your info.

McGiever · Post by **McGiever** » Tue. Jun. 16, 2015 6:15 pm

Actually, there is such a item...sort of a DIY UPS.
And it will transfer battery and charger.

http://www.cdw.com/shop/products/Tripp-Lite-Power ... ApP38P8HAQ

Pure Sine wave do make the price go up...http://www.cdw.com/shop/products/Tripp-Lite-2000W ... re&pfm=srh

hotblast1357 · Post by **hotblast1357** » Tue. Jun. 16, 2015 6:37 pm

Thanks for those sites, I thought I HAD too use a pure sine wave for the circulator and fan motor?

nepacoal · Post by **nepacoal** » Tue. Jun. 16, 2015 6:44 pm

I called Taco before buying the APS750 and they stated the non sine wave would work but result in slightly higher operating temps and could cause shorter pump life if used 100% of the time but used as an emergency backup it would be fine... Pure sine wave is better but as mentioned above, the price sky rockets.

As I mentioned, my pump motors whine a bit when in backup but work just fine. Been in operation for 3 years now.

hotblast1357 · Post by **hotblast1357** » Tue. Jun. 16, 2015 7:00 pm

Thanks, I have found pure sine waves on Amazon for under 200

McGiever · Post by **McGiever** » Tue. Jun. 16, 2015 8:43 pm

It takes 27 amps of 12 volt DC to run just a 300 watt inverter...so big enough wire size from batteries is a important part of the install.

I found this wire size calculator, you may find it handy: http://www.gtsparkplugs.com/WireSizeCalc.html

hotblast1357 · Post by **hotblast1357** » Wed. Jun. 17, 2015 4:35 am

Thanks mcgiever, my only other option here is to setup a non electric dump zone with a radiator or something, but I just don't have the spot to put it to thermsyphon.

McGiever · Post by **McGiever** » Wed. Jun. 17, 2015 8:13 am

hotblast1357 wrote:Thanks mcgiever, my only other option here is to setup a non electric dump zone with a radiator or something, but I just don't have the spot to put it to thermsyphon.

Thinking outside the box...and this is exactly a non-electric solution.

How about thermosyphon to a nice long length of fin tube mounted overhead activated by a normally open 24 volt zone valve. (stays closed always till power loss...then opens)