Solo mining Monero without downloading blockchain

Question

Is there a way with mining Monero solo without downloading the blockchain?

I have about 20 Raspberry Pi’s, which I didn’t pay for also I don’t pay for electricity. Downloading and syncing a large file on a Raspberry Pi isn’t very efficient, so is there a way to set it up without a pool?

I am trying to keep away from a pool because I wouldn’t be able to withdraw my balance until it gets up to a certain amount.

But with 20 free Raspberry Pi’s (half model b+ and half model b) and free electricity, will it be efficient to mine on a pool?

Answer 1

Borrowing from What are the chances of discovering a block solo mining with my current hashrate?

H = Network Hashrate (619.7 MH/s on 1/13/18)
h = Your hashrate (20 x 1h/s on RPb)
t = Average time to find a block

t = 120 / (h / H) = 120 * (H / h) (seconds) = (H / h) / 720 (days)

You: (619700000 / 20) / 720 = ~ 43,000 days

Is there a way...?

Absolutely

... without a pool?

No

efficient ?

Not in any form. This isn't about efficiency in this exercise.
As said in other threads, it's a lottery.

Another calculator is available here:
https://www.monero.how/monero-mining-calculator

Their projection ... 97yrs
Projection from above ... 117yrs
The variance between estimations seems reasonable.

Answer 2

No, definetley not worth the time required to set them up for solo mining, if that's even possible. If it is possible, you'll probably never win a block.

As for pool mining, I guess it depends on the hashrate you can get out of one board but for comparison my i7 does about 90H/s, where a single 1070 will do about 500-600H/s using less juice. If there is software for an ARM board to do pool mining, and if you connect them all to the same address I'd say you'd probably be able to make a very small withdrawal every couple of days if you choose a pool with a low withdrawal limit.

Even so, considering the time spend setting it up you'd be better of mowing your next doors neighboor's lawn once a month for some pocket money and wouldn't surprise me if you'd be making a more money for a LOT less time.