Inter-bike charging

[afzal]

Then maybe for safety's sake you should delete your post rather than even begin to make the suggestion?

Just saying.

Okay, deleted

 

[Bikes4two]

The general principle I use when paralleling my bike batteries is this (and I've been running my battery packs in this way for a year now):

1. The battery packs are of the same nominal voltage (in my case 36v packs)
AND
2. Before connecting them together (without any diode isolating, current limiting or other electronic means) ensure they are at the same charge state and this is determined by accurately measuring the off load 'at rest' battery voltage.

If the battery voltages are within 0.1v (100mV) of each other then I am happy to connect them in parallel.

Now that's the way I do it for the relatively low AmpHour capacity batteries I use. There are other methods but I don't use them and have no experience of them so I will not speculate as to their relative merits.

 

[matthewslack]

Thanks for posting about this. Which diode do you use? You may have mentioned it before on one of your solar trailer adventure threads, but I can't recall.

While you're here, how many solar panels would I need to power 100 of these to make an atmospheric water harvesting system for my off-grid garden?

TEC1-12703 Heatsink Thermoelectric Cooler Cooling Peltier Plate Module | eBay

Enables reduced, low-noises operation of cooling fans, while providing greater cooling power. Can provide cooling below ambient temperature. Suitable for manufacture in small size. hope you could understand.

www.ebay.co.uk

(1) Mine is an MBR6045WT, chosen because I read about someone else using it, and it was easily available. Not as a result of deep research!

(2) Many!

They seem to want (QM) 28W each, so 2.8kW for 100 of them. My three Sunpower lightweight panels are 110W peak output each, i.e. full sun and pointing at the sun, so you would need about 30 for instantaneous midday sunny day success.

But energy questions are more nuanced than this. E.g. how long do they need to run for, per day? And so on, will allow energy per day to be calculated, and then a plan made for how to supply it: how many panels, how much battery etc..

Cheapest panels are the conventional heavy domestic glass surfaced, and often bargains available from solar farm upgrades. Try Bimble Solar.

 

[guerney]

They seem to want (QM) 28W each, so 2.8kW for 100 of them. My three Sunpower lightweight panels are 110W peak output each, i.e. full sun and pointing at the sun, so you would need about 30 for instantaneous midday sunny day success.

But energy questions are more nuanced than this. E.g. how long do they need to run for, per day? And so on, will allow energy per day to be calculated, and then a plan made for how to supply it: how many panels, how much battery etc..

Cheapest panels are he conventional heavy domestic glass surfaced, and often bargains available from solar farm upgrades. Try Bimble Solar.

Thanks for the solar panel information. Bar this year, it hasn't rained much for the past couple of years. I might try a small scale test - with an ice conductance detector for when it blocks an aluminium pipe with a few CPU heatsinked peltier plates externally attached, thermally isolated as much as possible from the pipe sides being cooled. When the pipe is blocked with ice, the cooling should stop until the ice melts. Might turn out to be an absurdly inviable proposition.

 

[Cisco-man]

My favourite diode for this job.

post edit - I see the last post says the 60A one - could well be a better choice, but I’ve not had a 30A fial.

 

[Nealh]

The general principle I use when paralleling my bike batteries is this (and I've been running my battery packs in this way for a year now):

1. The battery packs are of the same nominal voltage (in my case 36v packs)
AND
2. Before connecting them together (without any diode isolating, current limiting or other electronic means) ensure they are at the same charge state and this is determined by accurately measuring the off load 'at rest' battery voltage.

If the battery voltages are within 0.1v (100mV) of each other then I am happy to connect them in parallel.

Now that's the way I do it for the relatively low AmpHour capacity batteries I use. There are other methods but I don't use them and have no experience of them so I will not speculate as to their relative merits.

 

[Nealh]

The general principle I use when paralleling my bike batteries is this (and I've been running my battery packs in this way for a year now):

1. The battery packs are of the same nominal voltage (in my case 36v packs)
AND
2. Before connecting them together (without any diode isolating, current limiting or other electronic means) ensure they are at the same charge state and this is determined by accurately measuring the off load 'at rest' battery voltage.

If the battery voltages are within 0.1v (100mV) of each other then I am happy to connect them in parallel.

Now that's the way I do it for the relatively low AmpHour capacity batteries I use. There are other methods but I don't use them and have no experience of them so I will not speculate as to their relative merits.

Yep , simple process of equalising voltages before connecting , charge to near same voltage . I have had no issue with 0.25v difference .