John Frum
Tell me your problems
- Joined
- Nov 30, 2019
- Messages
- 15,233
The bundled cables are not even fit to hold your pants up.
I thought everyone just threw them out with the packing peanuts.
600ah bank vs 1500w toaster oven
- Thread starter solarstuff
- Start date
I thought everyone just threw them out with the packing peanuts.
solarstuff
New Member
Lol yip got that now.
And the precipitous drop under load that disappears without a load is not actually hurting my battery? Just reminding me to install a monitor?
And the precipitous drop under load that disappears without a load is not actually hurting my battery? Just reminding me to install a monitor?
Do you have access to a clamp meter, so that you can measure the actual amps to the inverter under the high load? Also it may be helpful to check amp draw at each battery, to see if they are each contributing roughly the same amount. (Those draws are likely going to be fine though.)
A 250a fuse is a little high for the 1/0 wire. If you replace the inverter wires with 4/0, you would be good. (Note that your inverter can only make use of a max sustained 215 amps [about 2200 max watts / 12v / 0.85 efficiency ~~ 215a].)
As far as harming the batteries, no worries as long as they are healthy, and your amps rate is less than the battery's discharge rating. E.g. if each battery is rated at 75a sustained discharge rate, and you are drawing 200a with your load, you're drawing approximately 50a per battery. But, if a battery fails, then the other 3 are going to approach 67a each. And if one of those remaining 3 is "aging" faster than the others, and/or there is a connection problem, then conceivably you could exceed 75a on 2 of the 3 remaining batteries.
It's a nuisance, but for peace of mind you can separate the batteries once in a while and do a simple voltage and load test on each one. That would verify that it is still contributing well for (at least short-duration) high loads.
A 250a fuse is a little high for the 1/0 wire. If you replace the inverter wires with 4/0, you would be good. (Note that your inverter can only make use of a max sustained 215 amps [about 2200 max watts / 12v / 0.85 efficiency ~~ 215a].)
As far as harming the batteries, no worries as long as they are healthy, and your amps rate is less than the battery's discharge rating. E.g. if each battery is rated at 75a sustained discharge rate, and you are drawing 200a with your load, you're drawing approximately 50a per battery. But, if a battery fails, then the other 3 are going to approach 67a each. And if one of those remaining 3 is "aging" faster than the others, and/or there is a connection problem, then conceivably you could exceed 75a on 2 of the 3 remaining batteries.
It's a nuisance, but for peace of mind you can separate the batteries once in a while and do a simple voltage and load test on each one. That would verify that it is still contributing well for (at least short-duration) high loads.
chrisski
Solar Boondocker
- Joined
- Aug 14, 2020
- Messages
- 5,229
I’m looking at the recommended cable sizes for the SAMLEX inverter I may purchase, and for the 2000 watt model, minimum recommended wire size for a 12 VDC 2000 watt inverter is 2/0. For a 24 VDC 2000 watt inverter, the minimum recommended cable size is 4 AWG. These are specs from the manual, not numbers off a DC calculator I used.
I’m not sure how different AGM are from my FLA 478 ah battery bank, but I looked at running a 1700 watt electric kettle through that, and saw I would be pulling power out at the C1 rate. My battery manufacturer only publishes down to the C10 rate, but found for planning purposes, to multiply the C20 rate by .3 and get 143 amps at the C1 rate, which coincidentally nearly matched the draw of the kettle I planned on using. I also can‘T find a max discharge rate for the batteries I have, so I’m not sure if that part is safe.
So, when I assemble this system, I will want to install 2/0 for a 12 VDC system for the couple of feet of run I have From the battery to the inverter.
I’m not sure how different AGM are from my FLA 478 ah battery bank, but I looked at running a 1700 watt electric kettle through that, and saw I would be pulling power out at the C1 rate. My battery manufacturer only publishes down to the C10 rate, but found for planning purposes, to multiply the C20 rate by .3 and get 143 amps at the C1 rate, which coincidentally nearly matched the draw of the kettle I planned on using. I also can‘T find a max discharge rate for the batteries I have, so I’m not sure if that part is safe.
So, when I assemble this system, I will want to install 2/0 for a 12 VDC system for the couple of feet of run I have From the battery to the inverter.