2 200 amp vs 4 100 amp

[sleepy]

i am installing either 2 200 amp redodo or 4 100 amp redodo batteries, is having 2 batteries enough redundancy or am i better off with 4, was thinking the less connections the better??

[HuffinPuff]

More is always better... If you can do 3 200 amps, that would be the best of both worlds. Enough redundency and plenty of power.

[sleepy]

also am i better off with 2 dc dc 30 amp or 1 buck boost 50 amp 2 for redundancy?

[mvweebles]

I have six 100ah batteries. Cabling was a pain (bus bars with equal length cables in star config). I worry about them staying balanced. When time comes to replace, I'll go with fewer batteries of higher capacity to simplify. I sort of see your point about redundancy, but the chance of 4x100 lag running at peak performance is lower than 2x200ah.

BTW - hearing very good things about Epoch batteries. BMS will internally balance, and an option for Victron communications.

[wholybee]

Maybe instead of planning for failure, look at what makes a system reliable. If you think you will need more than one backup battery, something is not right. As a class, LFP batteries are extremely reliable, much more than AGM. If they fail, you probably killed it with something wrong, and you would quickly kill 4 as you would 2 or 1. Most people recommend the start battery as an emergency backup. You don't need more than that.
I would concern myself with what brands i bought over redundancy. Do not exclusively shop price on LFP. There are good brands that won't break the bank, and there is cheap crap. Same with DCDC. I would not concern myself with redundancy with Victron chargers. But cheaper brands you might have an event that kills both of them.
If you are planning a 400Ah bank, how are you charging it? If alternator is primary, ditch the dcdc and upgrade the alternator. If its not, do you really need more than 30A? 60A will burn up many stock alternators, so tread lightly.

[Eagle ITA]

"Cabling was a pain" well said!
Better 2x200
About redundancy, forget it; when a battery crash all the other batteries of the bank will crash in a very few time
If a 100Amp battery (in a bank of 4x100Amp) get failed, you will be about at zero Amp batteries bank, and not with a 3x100Amp bank.

For safety redundancy you have to have 2 banks of 2x100 separated...
...with all the complications of the case, It's not worth it (IMHO)

[thinwater]

Originally Posted by Eagle ITA

"Cabling was a pain" well said!
Better 2x200
About redundancy, forget it; when a battery crash all the other batteries of the bank will crash in a very few time
If a 100Amp battery (in a bank of 4x100Amp) get failed, you will be about at zero Amp batteries bank, and not with a 3x100Amp bank.

For safety redundancy you have to have 2 banks of 2x100 separated...
...with all the complications of the case, It's not worth it (IMHO)

It's Ah guys. The A is capitalized because amps are named for Andre Ampere.


This is distinct from CCA, which is not what you are discussing, I think.

[mvweebles]

Originally Posted by thinwater

It's Ah guys. The A is capitalized because amps are named for Andre Ampere.

Whew.....glad you cleared that up. I'm sure the entire CF universe was scratching their head trying to figure out what the heck "100ah" means.

[diverd]

I recently took out 4 x 110 ah batteries, monitored by a NADA BM1, with solar charging and all the usual cabels. One battery appeard to have failed and i had to disconnect them one by one to get the computer to check each one. It was a proper pest and in an emergency i could not have described to someone else how to put a jump starter on as an example.
I replaced them witrh 2 x 225 ah batteries, its now all super simple, i carry 2 jump starters as auxillary starting and power when out and about and its incredibly clean. If i had to start the engine and have someone else use tghe jumpstarter i could easily describe what to do. The Nasa is working way better, its monitoring properly as the batteries are now cleaner wired and its easier to see whats going on. Big though they are they are taking up less space than the 4 smaller ones and i would expect them to probably weigh less, niot that weight is overly important.
I thought more would be better with batteries, but with this new set up i am far happier, and a fault would be detected in moments rather than months, the solar was hiding it.

[HeinSdL]

Originally Posted by mvweebles

Whew.....glad you cleared that up. I'm sure the entire CF universe was scratching their head trying to figure out what the heck "100ah" means.

I think the reference was to the "100Amp battery"...

[sleepy]

i have 3- 200 watt renogy solar panels to charge lipo and a 100 amp agm starter battery i have a brand new beta 35 i believe it has a 70 amp alt. i am installing a 3000 victron invertor charger also have 3 100/30 mmpt victrons was going to charge starter battery with the beta dc to dc for house bank to keep from interrupting load. i will be solo sailing. i am a minimalist but will probably have an a/c / heat unit for the Caribbean, ecoflow maybe???

[wholybee]

Originally Posted by mvweebles

Whew.....glad you cleared that up. I'm sure the entire CF universe was scratching their head trying to figure out what the heck "100ah" means.

I always try to capitalize my units correctly. In some cases it actually makes a difference, though here it is simply proper because it refers to a person. I would be more concerned about the usage of "Amp" instead of "Ah" (or "ah") because that actually does create confusion in meaning at times. It also shows that the writer might not understand the electrical theory and the response should be treated as such.

I also note that English is most likely not Eagle ITA's first language, and as such I am ok reading around language mistakes.

[donradcliffe]

If you are going to power heavy loads with the bank, make sure if you go with two 200 ahr batteries that they each one has a 200 amp bms.

[sleepy]

wow just trying to exchange some ideas!! people SUCK thats way im solo sailing to get away from all the negativity

[wholybee]

Originally Posted by donradcliffe

If you are going to power heavy loads with the bank, make sure if you go with two 200 ahr batteries that they each one has a 200 amp bms.

I don't see anything on the redodo site that lists the size of the BMS. There is no reason to believe that the 200Ah battery has a 200A BMS. It very well might be the exact same BMS as the 100Ah battery. It might even be the same BMS as the 50Ah battery.

Personally, I would not even give the slightest bit of consideration to a battery that didn't list current handling capacity up front.