Battery help

[SpaceBus]

I want to run some of my outdoor electric stuff off of a battery instead of my generator. I'm looking at 20-30 AH LiFePO4 batteries and trying to figure out what kind of inverter I'll need. Primarily I want to run my Tecomec Super Jolly chainsaw grinder, which uses a 300 watt electric motor. I have a 30 Ah battery and 500 watt inverter in my Ebay cart. Anything else I should be thinking of?

 

[NorMi]

60A circuit breaker, wire, terminals/ends, 15A lifepo charger. If you're charging outside in the cold it's nice to have it installed in an insulated box with a heating pad in it on a temp controller. Another nice upgrade is a battery monitor since it's virtually impossible to get a good state of charge on lifepo from voltage readings alone. On small/cheap projects I use a watt meter type thing like this: (broken link removed to https://www.ebay.com/itm/222129924444). Larger projects I like to use the Victron BMV meter/shunt.

 

[semipro]

A few random thoughts:

• How do you plan to recharge the batteries? Potential for future solar charging?
• Per this, the motor is rated at 3.0 amp at 120 VAC so the actual continuous load may be closer to 360 watts. Most AC motors demand more power when starting up so you'll need to add capacity for that. The inverter you're considering may be rated for 500 watts continuous with some some surge capacity so it may handle that. I'd assume you may be needing light while sharpening so maybe add in some more capacity for lighting. If it were me I would consider going larger on the inverter if the increase in cost is acceptable.
• Are there other potential uses for the power system: lighting, Wi-Fi, fan, security camera, power tool charging, etc.?
• Use a portable power system instead?
• Protection from critters?

 

[SpaceBus]

60A circuit breaker, wire, terminals/ends, 15A lifepo charger. If you're charging outside in the cold it's nice to have it installed in an insulated box with a heating pad in it on a temp controller. Another nice upgrade is a battery monitor since it's virtually impossible to get a good state of charge on lifepo from voltage readings alone. On small/cheap projects I use a watt meter type thing like this: (broken link removed to https://www.ebay.com/itm/222129924444). Larger projects I like to use the Victron BMV meter/shunt.

I have a slow charger in the house, and I am also thinking about setting up a portable solar charging station. This is meant to be portable to use with some other tools like a 300 watt HPA compressor.

A few random thoughts:

• How do you plan to recharge the batteries? Potential for future solar charging?
• Per this, the motor is rated at 3.0 amp at 120 VAC so the actual continuous load may be closer to 360 watts. Most AC motors demand more power when starting up so you'll need to add capacity for that. The inverter you're considering may be rated for 500 watts continuous with some some surge capacity so it may handle that. I'd assume you may be needing light while sharpening so maybe add in some more capacity for lighting. If it were me I would consider going larger on the inverter if the increase in cost is acceptable.
• Are there other potential uses for the power system: lighting, Wi-Fi, fan, security camera, power tool charging, etc.?
• Use a portable power system instead?
• Protection from critters?

I am trying to basically make my own version of the product you linked. Eventually I do want to set up a simple solar battery charging station. Partly this is to get my feet wet with solar/battery projects and to apply what I've learned to bigger projects. I'll post links to the products I am interested in buying.


The 30ah battery

Solar trickle charger

(broken link removed to https://www.ebay.com/itm/393754756595?hash=item5bad9cc5f3:g:ukUAAOSwf8lhqH0q)

The linked inverter is actually beefier than the previous inverter I found, which is now gone.

 

[semipro]

I have a slow charger in the house, and I am also thinking about setting up a portable solar charging station. This is meant to be portable to use with some other tools like a 300 watt HPA compressor.


I am trying to basically make my own version of the product you linked. Eventually I do want to set up a simple solar battery charging station. Partly this is to get my feet wet with solar/battery projects and to apply what I've learned to bigger projects. I'll post links to the products I am interested in buying.


The 30ah battery

Solar trickle charger

(broken link removed to https://www.ebay.com/itm/393754756595?hash=item5bad9cc5f3:g:ukUAAOSwf8lhqH0q)

The linked inverter is actually beefier than the previous inverter I found, which is now gone.

One thing that's nice about going with a 12vdc battery is that it might be used for jump-starting equipment or powering 12vdc accessories directly (no inverter inline).
I assume you've spent some time online, particularly YouTube, researching what others have DIYed?

 

[SpaceBus]

One thing that's nice about going with a 12vdc battery is that it might be used for jump-starting equipment or powering 12vdc accessories directly (no inverter inline).
I assume you've spent some time online, particularly YouTube, researching what others have DIYed?

Yes, I've seen some really complex stuff, and some really simple stuff. I'm leaning towards simple, just a pre-made battery and the inverter. My HPA compressor is natively 12v, but works on 110v, and yeah, I was also planning on jumping vehicles if needed. Additionally I can use it to charge my Dewalt batteries. I've seen some really cool 200ah power stations made with lifepo4 cells and custom enclosures, high end inverters, and really slick wiring. I may do something like that in the future, but want to start small. We are hoping to mill enough lumber this winter to build a shed in the spring, and I want that building to be solar powered long term, and probably grid connected as well.

 

[NorMi]

The BMS on those batteries most likely will not handle the current of a jump start application, but otherwise it sounds good. At best it'll shut down the output, at worst the BMS will be damaged. I prefer the DIY build like you are doing, and this one you have in mind will be cheap/simple. make sure your trickle charger gets up to 14.4-14.6V without going over, so the cells will balance properly. A float charger/ lead acid style will let them drift over time as they never hit the top balance. The BMS may or may not have thermal protection for low temperature, if it doesn't and you charge the batteries under 40F, they will be damaged long term, so check that out and make arrangements. Many ways to skin that cat.

Using the circuit breaker (instead of a fuse) gives you a quick and easy disconnect switch for storage so you can store optimally over long periods at ~40% state of charge while it's sitting on the shelf to optimize lifespan without worrying about slow discharges from capacitors/electronics. It also gives you handy switch to reset a cheap watt meters back to zero if you ever add one in.

Other upgrades are to use a larger panel, 100-150w, upgrade to a mppt or even better a buck/boost mppt solar charge controller like Genasun ($$$) or a chinese equivalent if you can find a good one in your voltage/current needs. The buck/boost mppt's are uncommon, but they will charge the battery any time the panel voltage is above about ~5V, which is good for if you plan to encounter shading in a portable setup. Don't forget to get a correct size fuse block or another circuit breaker for between the solar charge controller and battery.

 

[peakbagger]

FYI Lithium Chemistry batteries are wimps when it comes to temperatures. They want to be kept within a narrower operating range than Lead Acids.

 

[woodgeek]

Sounds like a fun project. I'd put the whole battery/BMS/inverter on wheels, and think about upgrading to a sine wave inverter... Then you could run lots of stuff with it portably. And then plug it back into the solar array (assumed to be fixed).

 

[Solarguy3500]

How about something like this?

Portable Power Stations, Solar Generators & Home Backup | Goal Zero

Experience the power of Goal Zero by improving your lifestyle with our portable power stations, solar generators, solar panels, power banks, and home energy storage solutions.

www.goalzero.com

 

[woodgeek]

How about something like this?

Portable Power Stations, Solar Generators & Home Backup | Goal Zero

Experience the power of Goal Zero by improving your lifestyle with our portable power stations, solar generators, solar panels, power banks, and home energy storage solutions.

www.goalzero.com

I've never been a fan of those Yeti things, bc of the price. I think you can usually put something together for a small fraction of the price.