Bud Martin
Solar Wizard
- Joined
- Aug 27, 2020
- Messages
- 4,843
I see now. He can use high current battery selector switch instead. I myself use momentary switch for pre charge connected in parallel with the DC breaker.
Last edited:
Pre-charging with resistor.
- Thread starter B.T.
- Start date
Ampster
Renewable Energy Hobbyist
Wow you guys are awesome. Thank you for your guys’ help. I’ve updated my diagram and replaced the 3 way switch with a 200 amp circuit breaker reset fuse. Please correct me if I’m wrong but if I disconnect the circuit breaker and turn on the switch connected to the resistor line I can precharge my inverter? I also figured I might as well explain what I’m trying to do HAHA
i have a tennis ball machine that is 115v and 10 amps. I figured I’d need a continuous flow of 1200 watts, hence the inverter. I am probably wrong but I figured a 12V 20 Ah battery would get me about an hour of use, but I had hoped to use a 50 Ah battery in the future.
In any case I’ve included the updated schematic based on all of your guys’ input, the switch I purchased, and the inverter. I’m sorry for my lack of knowledge! Don’t want to waste anyone’s time, but am seriously so thankful for your guys wisdom!
i have a tennis ball machine that is 115v and 10 amps. I figured I’d need a continuous flow of 1200 watts, hence the inverter. I am probably wrong but I figured a 12V 20 Ah battery would get me about an hour of use, but I had hoped to use a 50 Ah battery in the future.
In any case I’ve included the updated schematic based on all of your guys’ input, the switch I purchased, and the inverter. I’m sorry for my lack of knowledge! Don’t want to waste anyone’s time, but am seriously so thankful for your guys wisdom!
Attachments
Bud Martin
Solar Wizard
- Joined
- Aug 27, 2020
- Messages
- 4,843
Stay away for that junk $11 200A breaker, get the real thing from Blue Sea (Eaton/Bussman).
HAHA I did watch it, but when I got 3/0 gauge and saw how huge it was I couldn’t believe it LOL
Haha okay got it ? thank you!
Yes, but proper wire size is what it would take to do the job without 6 AWG wires catching on fire.
That is part of why I mentioned 24 and 48v batteries.
If you need 200 amps at 12 volts you can deliver the same power with 100 amps at 24 volts or 50 amps at 48 volts.
Obviously smaller wire is able to safely carry the same power delivered at higher voltage.
Last edited:
And please don’t shoot the messenger but I have more bad news.
A 20 Ah battery cannot pump out 200 amps. If it could it would only last 1/10th of an hour. (20/200) which of course is only 6 minutes to work on your tennis game.
The good news is that you are making your mistakes on paper and figuring out things before you go buying the wrong stuff or setting things on fire.
I wish I had done more of that in the beginning ?.
Although in my defense it was usually more smoke than fire.
A 20 Ah battery cannot pump out 200 amps. If it could it would only last 1/10th of an hour. (20/200) which of course is only 6 minutes to work on your tennis game.
The good news is that you are making your mistakes on paper and figuring out things before you go buying the wrong stuff or setting things on fire.
I wish I had done more of that in the beginning ?.
Although in my defense it was usually more smoke than fire.
Last edited:
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 20,535
His schematic says 12V 50 Ah.
Load is 115V, 10A rated tennis ball launcher. But I hope it doesn't draw 1150W continuously, rather only when shooting a ball at him.
Time for a Kill-a-Watt meter?
12V x 50 Ah = 600 Wh. Is that AGM? If so, use maybe 50% to 80% of capacity. For personal use, a couple to a few hundred cycles should be enough. If commercial, need better. 600 Wh x 80% = 480 Wh usable.
Maybe it'll give an hour of practice, depending on average consumption.
An AGM battery can probably support 1C discharge rate, so 600W output. Due to Peukert effect, won't last an hour at 1C. It can give a high peak current, probably as much as a car starting battery for a few seconds. Not sure what current profile the tennis ball launcher has. I think it is a spinning motor with a wheel to throw the ball, so pretty much continuous no-load current draw I would guess.
Might be better to have a 12V motor. But inverter is an off-the-shelf product.
I just realized. Wouldn’t it just make more sense to skip the inverter and directly power the machine using a transformer or something? Is this feasible?
Bud Martin
Solar Wizard
- Joined
- Aug 27, 2020
- Messages
- 4,843
"Load is 115V, 10A rated tennis ball launcher" Your load requires AC to run, so if you want to run on DC then you need to change motor to run on 12VDC.
Last edited:
Well that's not happening haha 2/0 wire and 200 amp circuit breaker switch it is.
I saw online you're supposed to use a hydraulic press to crimp the lugs to 2/0 wire. Is this true? I was planning on just hammering away
Ampster
Renewable Energy Hobbyist
A hydraulic crimper makes a better crimp, especially on big wire. Years ago I did use one of those inexpensive hammer crimpers. It worked fine and was cost effective for one or two crimps. Later I had enough crimps that would be taking 400 Amps that I bought a hydraulic crimper.
D
Deleted member 23531
Guest
Hey, don't buy a crimper just for this project. Instead, buy pre-crimped cables from batterycablesusa.
I just did that this week and was very happy:
- they're inexpensive; cheaper than on Amazon despite being customizable
- they ship really fast
- it's high-end wire (105C insulation rating; apparently USA made)
- you can get custom diameter crimped ends on both ends
- you don't have to buy more crimp connectors than you need
- you don't have to buy a crimper
- they probably will do a better job than you will if this is your first time crimping
The downside is that if you need a crimped connector at both ends, you need to know your cable length in advance, so it requires a bit more planning. If you only need a crimped connector at one end (ex: because the other end goes into a breaker or other bare-wire terminal) then you can just order it a bit long and cut it to length as needed.
Edit: I got their "extreme" series since they're all super cheap. I figured out how to get 6 wires for my project by ordering 3 with custom ends and cutting them apart. Total cost was like $30. Shipping is only $4, which is great for a non-Amazon company.
I just did that this week and was very happy:
- they're inexpensive; cheaper than on Amazon despite being customizable
- they ship really fast
- it's high-end wire (105C insulation rating; apparently USA made)
- you can get custom diameter crimped ends on both ends
- you don't have to buy more crimp connectors than you need
- you don't have to buy a crimper
- they probably will do a better job than you will if this is your first time crimping
The downside is that if you need a crimped connector at both ends, you need to know your cable length in advance, so it requires a bit more planning. If you only need a crimped connector at one end (ex: because the other end goes into a breaker or other bare-wire terminal) then you can just order it a bit long and cut it to length as needed.
Edit: I got their "extreme" series since they're all super cheap. I figured out how to get 6 wires for my project by ordering 3 with custom ends and cutting them apart. Total cost was like $30. Shipping is only $4, which is great for a non-Amazon company.
Last edited by a moderator:
I can also recommend powerwerx, lots of hams use them. Shop around and get a good price.
powerwerx.com
Edit to add, this is probably not the cheapest place, like I said, shop around. If others recommend them and they are cheaper, go for it.
Custom DC Power Cables | Powerwerx
Design your own custom cable. We build & ship it to you. Specify your connectors, length, gauge and other options. Calculate the price in real time as you design, then add it to your cart.
powerwerx.com
Edit to add, this is probably not the cheapest place, like I said, shop around. If others recommend them and they are cheaper, go for it.
Last edited:
D
Deleted member 23531
Guest
Nice; yeah I'm not promoting BatteryCablesUSA in particular; just I had a good experience. Next time I would compare to what Powerwerx offers; I didn't know about them.
It looks like Powerwerx uses marine rated tinned copper lugs. BatteryCablesUSA says tinned copper, then gives more details of their ratings in the discrete lug purchase page: https://www.batterycablesusa.com/copper-lugs-terminals. I assume this is the same product as what they use for the premade cables. Not sure if it's marine rated, but I'm also not building anything near water. Actually they mention they're appropriate for marine cables, so I bet it's the same as Powerwerx.
Side note: I've noticed a lot of these very-specific internet companies popping up, which offer one specific domain of products and do it *really* well, much better than Amazon or other retailers that sell many different products. Another company I love with a similar business model is Bolt Depot.
It looks like Powerwerx uses marine rated tinned copper lugs. BatteryCablesUSA says tinned copper, then gives more details of their ratings in the discrete lug purchase page: https://www.batterycablesusa.com/copper-lugs-terminals. I assume this is the same product as what they use for the premade cables. Not sure if it's marine rated, but I'm also not building anything near water. Actually they mention they're appropriate for marine cables, so I bet it's the same as Powerwerx.
Side note: I've noticed a lot of these very-specific internet companies popping up, which offer one specific domain of products and do it *really* well, much better than Amazon or other retailers that sell many different products. Another company I love with a similar business model is Bolt Depot.
Last edited by a moderator:
Yes, I get nothing from it either, just had good experience. If you only need a limited number of cables, getting a quality cable pre-built will save time, money, and hassle (crimp tool, stripper, wire cutter, lugs, heat shrink, etc.)
If you have to do a lot of cables, then obviously you might want to invest in the proper tools.
