Author Topic: House Battery  (Read 45 times)

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Rbob

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House Battery
« on: February 22, 2021, 09:36:03 PM »
Just wondering what others have used or recommend.

My prior boat had one house battery, only electronics with hd pot puller, no windlass or diesel heater.

I was thinking about 2 6v agm batteries as house battery but that may be overkill and 150lbs +/- of batteries but capacity is 210Ah that is a lot.

Edited, running 6v in series capacity remains the same, thanks Json

Just dont want to kill a battery running the heater all night.



« Last Edit: February 23, 2021, 07:42:51 AM by Rbob »

json

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Re: House Battery
« Reply #1 on: February 22, 2021, 10:23:40 PM »
I think you would need to run those in series to get the voltage to 12v +- for the house system, so your Ah capacity would only be 210 total. I thought this was a good amount until I started doing the 'add up everything and make a day estimate of usage' exercise. My bait tank pump alone is 8 amps @ 12 volts dc, so if I run that thing continuous off house for 24 hours that's 192 amp hours... Something else to consider is the usable capacity, which from my understanding is about 30% of your lead acid bank if you want your batteries to last (using partial state of charge between 80% and 50%), so this brings your 210 amp hour bank down to around 65 amp hours.

I read an article today that got my inner mad scientist all riled up about building a lithium iron phosphate bank from chinese cells. It doesn't seem very difficult and for a fraction of the cost of buying a commercial lithium iron phosphate system you could have a pretty high capacity bank that you knew in and out. The downside of course is if you screw up the cost could be very high, up to and including a fire on board in a not so great situation... a couple years ago I built an electric skateboard that has a 60 18650 cell lithium ion battery in it, and while the battery works great (and the skateboard too) it is downright scary how much energy is in that thing and thinking about what would happen if it got into a thermal runaway.

https://www.svavocet.com/2021/02/22/powered-by-home-built-batteries/

Rbob

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Re: House Battery
« Reply #2 on: February 23, 2021, 08:07:41 AM »
Yes on the 6v in series = 12v, thanks for the info about capacity staying the same.

I need to do some more research.  Most fishing type boats I have been on / seen have one house battery so maybe it will have to be enough. 

Looking into Firefly AGM Foam Core:
https://www.pysystems.ca/resources/ask-pys/firefly-oasis-vs-agm-vs-flooded-increasing-effective-bank-capacity-david/
« Last Edit: February 23, 2021, 10:49:36 AM by Rbob »

json

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Re: House Battery
« Reply #3 on: February 23, 2021, 10:51:35 AM »
Not sure which heater you have, assuming a wallas, the spec for the 30DT says it uses 0.8-1.8 amps, so also assuming middle of that running non-stop you would use around 30 amps per day... You can always start small and scale up if/when the need arises and after you get a feel for how much NRG you will be using. You can also supplement with things like solar or wind, although solar panels would probably be kind of grumpy most of the time in the pacnw :P

Rbob

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Re: House Battery
« Reply #4 on: February 23, 2021, 04:07:29 PM »
I found a great video explaining battery types pros and cons.  Looking like Firefly Oasis might be a good choice:

https://www.youtube.com/watch?v=X6rwFN35oBY
« Last Edit: February 23, 2021, 04:12:54 PM by Rbob »

rhenryinoregon

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Re: House Battery
« Reply #5 on: February 23, 2021, 06:51:32 PM »
Iíve been watching the guys who buy off AliExpress and build their own packs. Itís very intriguing but I have trust issues. Iím a year out from that decision so maybe Iíll feel more comfortable by then. I am figuring on flexible solar panels on top though, and maybe a little egg beater generator as well. I just donít want my boat to look too much like a Christmas tree.
Randy Henry, SILVERTON Oregon
Randy_Henry@msn.com

ghelland

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Re: House Battery
« Reply #6 on: February 23, 2021, 11:19:07 PM »
I know the price sounds tarible ($1600) but the best option i have found so far is the Dakota lithium battery, 200Ah and you can use almost all of them.   Made in America and the company sounds solid.  I currently have 2 golf batteries in a camper and run a fan on the heater all night when it is cold.  The drain on the batteries is too high for me so my boat will have a larger bank.  There is a power usage calculator on the Ranger tug sight that might be a good place to start.