User Tools

Site Tools


electrical:solar:slim_reserve

This is an old revision of the document!


Slim battery reserves

Note: this section is likely not appropriate for newbies; if the ideas are implemented incorrectly it could result in battery murder and disappointment.

Running slimmer-than-normal battery reserves saves space, money, and weight. Here we discuss some ideas about reducing calculated reserves. For purposes of illustration, we will assume the vandweller's daily power requirements are 100Ah, and that they are using lead chemistry batteries.

Days of reserve calculations usually assume poor solar harvest == zero solar harvest. In reality this is almost always incorrect; some solar power is harvested even under dark overcast or rainy conditions.

In light-colored full overcast I see yields 25% of usual. In dark full overcast, as when storming, I see yields 10% of usual. – secessus

techniques

Overpaneling (having extra panels) may be required, as well as the addition of alternator or other forms of additional charging.

Time-shifting loads to periods of excess power will help keep the bank fully charged until the sun goes down.

fractional reserves

A fractional reserve might be a half- or quarter day of battery reserve. This takes into account the (reduced) contributions from your solar, alternator, etc. It may also require going into voluntary power-rationing mode when solar output is very low.

Overpaneling 2:1 or more will help gather more solar energy when running slim reserves in poor insolation.

zero reserves

In areas with abundant and consistent insolation like the desert southwest, you may be able to run with no reserves at all.

electrical/solar/slim_reserve.1579481530.txt.gz · Last modified: 2020/10/11 19:48 (external edit)